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130 Cards in this Set

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Type of epithelium of oral cavity, simple passages, digestive tract

oral and simple = Stratified squamous non-keratinised epithelium


Digestive - simple columnar epithelium

Tongue


- Epithelium


- Muscle type


- other contents

Stratified squamous epithelium, that mayt be para-keratinised with excessive wear and tear.




Skeletal muscle arranged in bundles at right angles to each other.




Contains numerous seromucous glands

What are the 4 papillae types and locations. Which are involved in taste.


For the ones involved in taste:


- innervation of all


- which contains Von Ebner glands

Filiform is only one not involved in taste. 


Innervation
Circumvallate - CN lX
Foliate - CN lX and CN Vll
Fungiform - CN lX and CN Vll


Von Ebners glands are located at the bottom of crypts of foliate and circumvallate papillae. Function to was...

Filiform is only one not involved in taste.




Innervation


Circumvallate - CN lX


Foliate - CN lX and CN Vll


Fungiform - CN lX and CN Vll




Von Ebners glands are located at the bottom of crypts of foliate and circumvallate papillae. Function to wash away taste molecules for new taste and secrete lingual lipase for saliva.

What separates the anterior 2/3 of the tongue from the posterior 1/3?

Sulcus terminalis

Taste of tongue, innervation of post 1/3, anterior 2/3, and posterior to pharynx

Post 1/3 - CN lX (glossopharyngeal n)


Ant 2/3 - CN Vll (facial n)


Posterior to pharynx - CN X (Vagus)

Location of


- Gingiva


- Enamal of tooth


- Dentine of tooth


- Pulp chamber of tooth


- periodontal membrane


- Cementum


- root canal of tooth


- Vermillion border


- Labial sulcus

Embriological layers that form:


Enamel


Dentin


Cementum


Pulp


Periodontal ligament




When does the dental lamina appear?


What do these dental lamina give rise to?


Once the enamel is forming, what condenses and what does it form.

Enamel from ectoderm.
Dentin, Cementum, Pulp and periodontal lig are from mesoderm. 


4 Dental laminae appear at wk 6. 


They eventually give rise to 4 enamel organs which develop into incisors, canines and 1st molars. Later the dental lamina gi...

Enamel from ectoderm.


Dentin, Cementum, Pulp and periodontal lig are from mesoderm.




4 Dental laminae appear at wk 6.




They eventually give rise to 4 enamel organs which develop into incisors, canines and 1st molars. Later the dental lamina give rise the the enamel organs for the other molars.




Mesenchyme then condenses to form dental papilla.

What are the names of the cells that produce enamel and dentine

Enamel is produced by ameloblasts. Once the tooth breaks through the gum, these cells are lost so no more enamel can be produced.


Dentin is produced by odontoblasts.

What is a dentine tubule?

Dentine tubules contain the apical processes of odontoblasts, these cells produce dentin.

What are the clinical correlations of an inability to produce ameloblasts?

Amelogenesis imperfecta - small, discoloured, pitter or grooved teeth seen that easily break due to no ability to make enamel.

Salavary glands names, types




Compsition of saliva (4)

Parotid - serous


Submandibular - mixed 80% seroud, 20% mucous, with striated ducts


Sublingual - 80% mucous, 20% serous, with striated ducts




Composition of saliva


- Mucins - lubricates, and immune role


- Amylase - starch digestion


- Lingual lipase - digests fats


- slightly alkaline electrolyte solution - moistens and neutralises oesophagus

what is this gland?

what is this gland?

Parotid salivary gland - just serous acini, also note the adipose tissue in the right image dont confuse this with mucin. striated ducts

What is this gland?

What is this gland?

Submandibular gland - mostly serous with some mucous acini displaying serous demilunes (SD),

What is this gland?

What is this gland?

Sublingual salivary gland - mucous acini with some serous acini only present as serous demilunes.

What ducts are there and which modify the secretions.




For each ducts describe its epithelium

Intralobular (intercalated and striated ducts) -> Interlobular -> Lobar ducts




Only the intralobular ducts modify secretions.




Intercalated ducts - simple squamous epithelium to Low cuboidal epithelium.


Striated ducts - Simple tall cuboidal to low columnar epithelium.


Interlobular - cuboidal or columnar epithelium.

Name the 4 layers of the GIT and their contents

1. Tunica mucosa


- epithelium


- lamina propria


- muscularis mucosa


2. Tunica Submucosa


- CT


3. Tunica Muscularis


- inner circular


- outer longitudinal


4. Tunica Serosa or Adventitia


- simple squamous epithelium and/or CT

As you travel down the GIT, what layer are most of the changes seen? What are these changes?

Tunica Mucosa. There are changes in the epithelium and associated glands

Tunica Mucosa. There are changes in the epithelium and associated glands

What Mucosa is seen in the oesophagus? And where is the lubrication obtained? What other

Stratified squamous non-keratinised epithelium. Lubrication is from the saliva from the oral cavity. There are also muscles for movement.

What is the histological structure of the oesophagus?

A collapsed lumen is lined by SS epithelium. The muscularis mucosa is disjointed superiorly and thickens inferiorly. The tunica muscularis is skeletal muscle superiorly and smooth muscle inferiorly. There also may be submucosal glands. Mostly the...

A collapsed lumen is lined by SS epithelium. The muscularis mucosa is disjointed superiorly and thickens inferiorly. The tunica muscularis is skeletal muscle superiorly and smooth muscle inferiorly. There also may be submucosal glands. Mostly there is tunica adventitia.

What epithelial change occurs going from oesophagus to stomach?

SS epithelium -> S cuboidal epithelium. Also the epithelium in the stomach arranges into gland crypts.

What can GER (gastroesophageal reflux) lead to? Also what are some suggested factors leading to GER?

Heartburn, mucosal ulceration, narrowing of oesophagus, Barret's metaplasia and eventually oesophageal cancer. Suggested factors include transient relaxation of the lower oesophageal sphincter (LES), hypotension of LES and poor oesophageal motility.

What lines the stomach. What are all the cells capable of secreting? What is the name for the arranged infoldings of the epithelium?

SS epithelium with NO goblet cells. All capable of secreting neutralising alkaline mucus. Infolding epithelium form gastric pits which have several gastric glands that open into each.

What are the three HISTOLOGICAL classifactions fo the stomach regions? And what differences in gastric pits are there (depth and number)?

1. Cardiac - pits are around 40% the depth of the mucosal layer and are few in number with lots of visible lamina propria.


2. Body + fundic - shallow 10% depth of mucosa with a vast number of tightly packed pits.


3. Pyloric - deep 70% depth of mucosa with a moderate number of pits with lots of lamina propria visible

What cell types are present in the glands of each layer? function, appearance.

Body/fundic


1. mucous neck cells


2. parietal cells - round central nuclei, abundant cytoplasm (fried egg), secrete HCL and intrinsic factor. When at rest with a smooth membrane they are described as a tubulovascular system, when actively secreting canaliculi are visible. Found in the neck region of gland.


3. chief/Zymogenic cells - Secrete pepsinogen which is converted into pepsin by HCL. Stain basophilic and are found in base of gland. They are stimulated by PSNS and gastrin,histamine from enteroendocrine cells (ENS)


4. enteroendocrine cells - they are found throughout the GIT but esp. stomach and SI. In an Electro Micrograph microvilli are visible which gather luminal contents which may stimulate the cell to release secretory vesicles (visible under EM) into the blood.

What are the ways the SI increase SA? (4)

1. Plicae circlares - which are permanent folds of mucosa and submucosa in the duodenum and jejunum. Similar folds are found in the colon (but are non-permanent) and in the stomach (called rugae)




2. Villi - finger like, core of lamina propria covered by epithelium. Between the villi are gland openings which extend into the lamina propria as far as the muscularis mucosa. There are either intestinal glands or crypts of lieberkuhn. They are simple coiled glands




3. Crypts of Lieberkuhn




4. Microvilli - finger like, core of cytoplasm containing many actin filaments, some ervidence of glycocalyx can be seen on the surface.

What is glycocalyx

Glycoproteins and intramembranous enzymes. It is covers microvilli of the SI. It adds to the digestion brought about by the gastric and pancreatic enzymes (peptidase, glycosidase, oligosaccharidase). This glycocalyx + the actin filaments of the microvilli make them acidophilic.

What are the 5 cells of the SI

1. Columnar absorptive cells (enterocytes) with microvilli
2. Goblet cells - 1-2 cycles every 2-4 days. use compound exocytosis with random fusion of the secretory vesicles before exocytosis. 
3. Enteroendocrine cells - secrete CCK (cholecystoki...

1. Columnar absorptive cells (enterocytes) with microvilli


2. Goblet cells - 1-2 cycles every 2-4 days. use compound exocytosis with random fusion of the secretory vesicles before exocytosis.


3. Enteroendocrine cells - secrete CCK (cholecystokinin), secretin and GIP (gastric inhibitory polypeptide). They have basal dark staining granules.


4. Paneth cells - secrete lysozyme (digests bacteria walls), defensins and phospholipase A2, these secretions mean P cells are acidophilic


5. Stem cells - replace the other cells which have a rapid turnover of ~ 7 days, these cells show dark basophylic mitotic figures during their mitosis.

Intestinal absorptive cells - enterocytes

These cells with a life span of 5-6 days, are replaced by stem cells in the base of the crypts of lieberkuhn.




Fat broken down by pancreatic lipase mix with bile salts to form micelles which are then absorbed then reconstituted into triglycerides, which then bind with proteins to form chylomicrons. These then pass into lacteals of the lamina propria and re-enter the blood stream.

Crypts of lieberkuhn

Mucosal glands that do not go into the submucosa. Simple coiled tubular glands. open into the lumen of the SI between villi. Between the glands is LCT of the lamina propria. Enzymes on the surface of the cells within the glands complement secretions of the pancreas and liver and are important in the digestion of proteins, carbs and lipids.

Brunner's glands

Only found in the duodenum. They are compound tubular glands that secrete alkaline mucous that neutralises the acidic chym from the stomach. There are Submucosal glands that open via ducts at the base of the villi. The glands are seperated from t...

Only found in the duodenum. They are compound tubular glands that secrete alkaline mucous that neutralises the acidic chym from the stomach. There are Submucosal glands that open via ducts at the base of the villi. The glands are seperated from the mucosa by the musculars mucosa.

The pyloro duodenal junction, what is on either side and how to tell histologically.

the pyloric sphincter can be identified by the thick muscularis mucosa. The duodenum epithelium shows microvilli and goblet cells which are not present in the stomach. Also in the duodenum will be the presence of the submucosa brunner's glands.

How is the Ileum identified apart from the rest of the SI.

There is the presence of the payer's patches. Which are mini LNs with a unidirection lymph outflow. Basophilic MALT can be seen within the patch with M cells at the luminal edge that constantly sample chyme for nastiness. Goblet cells are most abundant in the ileum.

The LI

1. 3 bands of longitudinal muscle - taenia coli


2. large numbers of goblet cells


3. No villi


4. crypts are straight tubular glands, an extend only to the Muscularis mucosa.


5. major function is water resorption and provision of sufficient mucous to lubricate the dry faeces.



Anal sphincters

simple squamous non-keratinised epithelium. Muscularis mucosa is thickened of the internal anal sphincter.

this is contrasted to the rectum where  there is a thinner muscularis mucosa and a mucosal gland area.

simple squamous non-keratinised epithelium. Muscularis mucosa is thickened of the internal anal sphincter.




this is contrasted to the rectum where there is a thinner muscularis mucosa and a mucosal gland area.

appendix

It is difficult to see due to the MALT but there are colonic mucosa present with glands.

Summary of layers across the oesophagus -> colon

Liver blood supply

Liver has dual blood supply. 1 supply - Hepatic portal vein brings nutrient rich but oxygen depleted blood from GIT. 2 supply - Hepatic portal artery brings oxygen rich blood from the aorta to supply the liver. The 2 blood mix in the portal regions, then go through sinusoidal capillaries (discontinuous simple squamous endothelium with macrophage kupffer cells) to hepatocytes. This blood then collects in central veins -> IVC





Liver architecture

Liver is arranged in hexagonal lobules each around a central veins. The hepatocytes in sheets lie around the central vein. These sheets are separated by sinusoidal capillaries. At the periphery of each lobule is an area (called the portal area) w...

Liver is arranged in hexagonal lobules each around a central veins. The hepatocytes in sheets lie around the central vein. These sheets are separated by sinusoidal capillaries. At the periphery of each lobule is an area (called the portal area) where the hepatic portal vein, hepatic artery, lymphatic vessel and bile duct are found.

Structure of a hepatocyte

Cuboidal cells with micro villi on the sinusoidal sides of the cells. that extend into the space of Disse. There are gaps between the sinusoidal  cells to allow leakage into the hepatocyte. There are organelles within that show is it has secreto...

Cuboidal cells with micro villi on the sinusoidal sides of the cells. that extend into the space of Disse. There are gaps between the sinusoidal cells to allow leakage into the hepatocyte. There are organelles within that show is it has secretory functions (golgi, rER, sER, Mitocondria and glycogen granules). The lateral walls contain bile canaliculi which are unlined channels that carry bile produced by hepatocytes.




Within the space of disse are Ito cells (hepatic stellate cells, HSC) which are thoughts to produce Vit A.

The gallbladder

An outgrowth of the duodenum. Lined by simple columnar epithelium with evidence of a brush border. Intercellular spaces are seen in the basal regions of the epithelium.

Which cell is non-absorbing and which is concentrating bile?

Which cell is non-absorbing and which is concentrating bile?

A = non-absorbing


B = concentrating vile (absorbing)




Note the extensive intercellular spaces created by resorbed material which cannot be carried away fast enough by the blood in the laminal propria.

the pancreas

it has exocrine and endocrine (islets of langerhans, which is the only thin that means you can differentiate pancreas from parotid gland ) components.




under high power it can been seen that each acinus has a basophilic (from rER in the cells) basal region and an eosinophilic (from zymogen granules) apical region.




The acinus has an intercalated duct made of centroacinar cells that extends into the lumen of the acinus. The zymogenic cells secretive digestive enzymes and the centroacinar cells make HCO3-. These secretions are under the control of CCK and secretin which are both secreted by enteroendocrine cells of the duodenum.

Adrenal gland cortex

Cortex - mesoderm origin, produce steroid hormones, regulated by ACTH from
the adenohypophysis.

					
				
			
		
	


Zones 
Zona glomerulosa

						aldosterone (mineralocorticoid)
renin-angiotensin control

						from the kidney 
...

Cortex - mesoderm origin, produce steroid hormones, regulated by ACTH fromthe adenohypophysis.




Zones


Zona glomerulosa aldosterone (mineralocorticoid)renin-angiotensin control from the kidney




Zona fasciculata cortisol (glucocorticoid)ACTH control




Zona reticularis androgens (steroid)ACTH control

Adrenal gland medulla

Medulla - neural crest origin, secretes catecholamines (epinephrine, norepinephrine), part of the sympathetic nervous system. 

Histo
- cells are modified neurons (sympathetic ganglion) - no post ganglionic fibres* 
- basophilic cytoplasm 
- ...

Medulla - neural crest origin, secretes catecholamines (epinephrine, norepinephrine), part of the sympathetic nervous system.




Histo


- cells are modified neurons (sympathetic ganglion) - no post ganglionic fibres*


- basophilic cytoplasm


- numerous fenestrated capillaries and large venous channels present




The secretory cells of themedulla (neurons) are innervatedby preganglionic fibres fromneurons located in the centralnervous system.Acetylcholine (Ach) releasedfrom these axon terminals causesthe release of hormones from theadrenal medulla.

Functions and Anatomy of the Kidney

Functions


• Elimination of excess waterand electrolytes as urine


• Excretion of toxic metabolicwaste


• Acid-base balance


• Secretion of hormonesrenin and erythropoietin




Anatomy


Outer cortex -


Renal capsule – denseirregular connectivetissue


• Outer cortex consists oftwo distinct regions: (1) Cortical labyrinths, and


(2) Medullary rays and




inner medulla


• Medulla consists of renal(medullary) pyramid


• Renal columns betweenlobes


• Lobes are furthersubdivided into lobules


• A cortical lobule is afunctional division, not ananatomical division
Lobes
: 8 to 12- consist of renal (medullary)pyramid + adjoining cap of cortex.




Renal columns between lobes




Hilum: (opening to kidney)


• renal artery


• renal vein


• ureter




Renal sinus contains:


• renal pelvis


• major and minor calyces


• arteries, veins and nerves


• loose connective tissue and fat

Histological Structureof the Kidneys: Development

The human kidney is multi-lobed (likethe ox kidney) but after birth itsmoothes out the surface to acquire thetypical adult smooth kidney shape.




This is a section of a human fetal kidneystill showing evidence of the multilobedarrangement.




Your sections of the rat kidney in thepractical class have only one lobe perkidney.

Blood supply of the kidney (the sequence is in the exam)

Blood supply – renal artery, segmental a., interlobar a., arcuate a., interlobulara., afferent arterioles, glomerulus, efferent arteriole, peritubular capillaries andvasa recta. Then the venous return.




Note:


Arcuate arteries at the junction between the medulla and cortex.


Interlobular arteries usually within the cortical labyrinths.


Afferent and efferent arterioles are usually difficult to visualise.


Peritubular capillaries are found between PCT and DCT in cortical labyrinths.


Vasa recta are the capillaries found in the medulla.

Kidney Histology

The kidney is arranged into functional unitscalled nephrons.




A nephron consists of a renal corpuscle +renal tubule (white, blue, red and orange inthe diagram).




The yellow tube is the collecting duct andis not embryologically part of the nephron.Together, the nephron and the collectingduct forms a structure called the uriniferoustubule.



Further subdivisions of the nephron.




Renal corpuscle consists of a glomerulus(blood capillary tuft) and a Bowmanscapsule.




The tubular part of the nephron consists of:


1. proximal convoluted tubule,


2. loop of Henle (descending and ascendingportions) and


3. distal convoluted tubule.




There are thick and thin portions of the loopof Henle.





Types of nephrons

There are two types of nephrons - depending on their position within the lobe.




Cortical nephrons with short loops of Henle that may not even penetrate into the medulla. Involved in the production of bulk urine volume.




Juxtamedullary nephrons that have long loops of Henle that extend deep into the medulla and that are responsible for maintaining the correct osmolarity of the urine.




Note the locations of the different parts of the loops of Henle.

Renal corpuscle appearance

Renal corpuscle = glomerulus + Bowman’s capsule 


						These are all in the cortex and are surrounded by the proximal and distal
convoluted tubules. Each kidney has between 200K – 2 million glomeruli.

Renal corpuscle = glomerulus + Bowman’s capsule




These are all in the cortex and are surrounded by the proximal and distalconvoluted tubules. Each kidney has between 200K – 2 million glomeruli.

How does the renal corpuscle form?

The invagination of the glomerulus into the end of the tubule creates a double layer
to Bowmans capsule - an outer parietal layer of simple squamous epithelium
and an inner visceral layer where the cells have become highly modified and are
call...

The invagination of the glomerulus into the end of the tubule creates a double layerto Bowmans capsule - an outer parietal layer of simple squamous epitheliumand an inner visceral layer where the cells have become highly modified and arecalled podocytes.


Each renal corpuscle has a vascular pole and a urinary pole.




Mesangium is found between the capillaries and consists of a basement membrane-like material and cells described as mesangial cells. These cells are thought to have phagocytic activity and also contractile functions, as well as hold things together.



Efferent and afferatn arterioles of glomeruli

The efferent arteriole is much smaller because due to the loss water, the Radius must decrease to maintain blood pressure.

Components of glomerular filtration barrier (membrane):

• fenestrated capillary endothelium (endothelial fenestrae without diaphragms) 
•  glomerular basement membrane – fused basal lamina contributed by both
endothelial cells and podocytes 
• secondary foot processes of podocytes, filtratio...

• fenestrated capillary endothelium (endothelial fenestrae without diaphragms)


• glomerular basement membrane – fused basal lamina contributed by bothendothelial cells and podocytes


• secondary foot processes of podocytes, filtrations slits, filtration slit diaphragms

How does the glomerular filtration barrier (membrane) work?

The negative charge in the BM, the fenestrae diaphragm, the

Proximal Convoluted Tubule

• lined by a simple cuboidal
epithelium 
• prominent brush border (tall
microvilli)
 • numerous mitochondria 
• highly folded lateral and basal
cell membranes to increase
surface area. 

 Function – reabsorbs 65% of
glomerular ...

• lined by a simple cuboidalepithelium


• prominent brush border (tallmicrovilli)


• numerous mitochondria


• highly folded lateral and basalcell membranes to increasesurface area.




Function – reabsorbs 65% ofglomerular filtrate• sodium ions, glucose, water• small amounts of excretionand secretion.




Filtration.


- lots of apical lysosome and vesicles for endocytosis


- lots of mitochondria helping with active transport.


- infoldings at the base increase SA for the many ion channels.




Note: The DCT has a pale staining lumen. The cells are pale staining due to less mitochondria, and lack of microvilli.



Loop of Henle

Thick descending – continuation
of PCT (simple cuboidal) 

 Thin descending – simple
squamous 

 Thin ascending – same as thin
descending 

 Thick ascending – same as DCT
(simple cuboidal)



Most of the elements of the loop of H...

Thick descending – continuationof PCT (simple cuboidal)




Thin descending – simplesquamous




Thin ascending – same as thindescending




Thick ascending – same as DCT(simple cuboidal)








Most of the elements of the loop of Henle are found in the medulla (or the medullaryrays). As a consequence when you look at the medulla you find profiles of a number ofdifferent structures. How do you tell them apart? (Note do not memorise)


Thin limb of the loop of Henle (T) - simple squamous epithelium


Thick descending and ascending limbs (A) - low cuboidal epithelium


Collecting tubule or ductule (CT) - low cuboidal epithelium


Vasa recta (V) - simple squamous epithelium, often with rbc’s.


Collecting duct (CD) - pale stained simple columnar epithelium

Distal convoluted tubule

• shorter, less convoluted than PCT 
• no brush border, few short microvilli 
• connects with collecting ducts which
begin in the medullary rays. 

 Function: Increased reabsorption of Na+
ions (and as a consequence the passive flow
o...

• shorter, less convoluted than PCT


• no brush border, few short microvilli


• connects with collecting ducts whichbegin in the medullary rays.




Function: Increased reabsorption of Na+ions (and as a consequence the passive flowof chloride ions) is controlled byaldosterone. Water movement out of thetubule only occurs in the presence of ADH.




Every distal convoluted tubule returns andmakes contact with the vascular pole of itsrenal corpuscle. This creates a structurecalled the macula densa which is part ofthe juxtaglomerular apparatus (helps to reg blood volume and blood pressure).




The juxtaglomerular apparatus is an association of different cell types and structuresfound close to the glomerulus (hence its name) and which is involved in regulating bloodpressure by activating the renin-angiotensin-aldosterone system.




The juxtaglomerular apparatus includes:


macula densa in the distal convoluted tubule (detect low Na conc, and stim release fo renin)


juxtaglomerular cells of the afferent arteriole wall


Lacis cells (extraglomerular mesangial cells) ofthe mesangium.




Juxtaglomerular cells are modified smooth musclecells in the wall of theafferent arteriole that secretethe hormone renin inresponse to decreased bloodpressure.

What is the role ofLacis cells in the renin-angiotensinogen system?

They probably act as a conduit


1. between the macula densa and thejuxtaglomerular cells and


2. between the macula densa and themesangial cells of the glomerulus.




The intraglomerular mesangial cells arethought to change the size of the lumen ofthe glomerular capillaries by contraction andrelaxation.

The collecting ducts and tubules

The collecting ducts and tubules are lined by a simple columnar orcuboidal epithelium. Clearly visible cell boundaries. There are 2 distict cell types presentin the epithelium:


1. Principal cells (or light cells or CD cells) which contain many ADH regulated waterchannels. These are the true functional cells. They have a pale cytoplasm and a singlecilium.


2. Dark cells (or Intercalated cells). These play a role in acid-base balance.

From collecting duct to urinary epithelium

 The collecting tubules and ducts
travel towards the tip of the
medulla. The larger end ducts are
often referred to as Ducts of
Bellini. They release urine into the
cavity of the minor calayx. This is
the beginning of the ureter lined
by u...

The collecting tubules and ductstravel towards the tip of themedulla. The larger end ducts areoften referred to as Ducts ofBellini. They release urine into thecavity of the minor calayx. This isthe beginning of the ureter linedby urinary or transitionalepithelium.

Flow of urine after the kidney.


The ureter



minor calyx - major calyx - renalpelvis - ureter - bladder - urethra.




Ureter


- folded mucosa (becomes more sodistally)


- transitional epithelium


- fibroelastic lamina propria (LP)


- muscularis of smooth muscle


inner longitudinal (L)


middle circular (C)


outer longitudinal (in the distal part of ureter)




In regards to ureter: Transitional epithelium appearance.

Transitional epithelium looks stratified and has a surface layer ofdome shaped cuboidal cells.


Outer longitundinal muscle is only present in the lower third ofureter.


Peristalsis moves urine towards the bladder.

Urinary bladder

Urinary bladder

						Intercellular tight junctions between the
epithelial cells.
The epithelium changes appearance
depending on the volume of urine present in
the bladder.

					
				
			
		
	


The cell membranes of the
surface ce...

Urinary bladder Intercellular tight junctions between theepithelial cells.The epithelium changes appearancedepending on the volume of urine present inthe bladder.




The cell membranes of thesurface cells of the bladderepithelium are furtherspecialised by the presence ofrigid, hinged plates or plaques.These in the empty bladder arefolded inside the cell cytoplasm(like a music accordion) butthey can unfold and increase thesurface area as the bladderdistends.

Urethra: male and female

Male: 
- Preprostatic urethra is found between
the urinary bladder (internal urethral
sphincter) and the prostatic urethra 
- Prostatic urethra is embedded in the
prostate gland 
- Membranous urethra connects the
prostatic and penile urethr...

Male:


- Preprostatic urethra is found betweenthe urinary bladder (internal urethralsphincter) and the prostatic urethra


- Prostatic urethra is embedded in theprostate gland


- Membranous urethra connects theprostatic and penile urethra and passesthrough the urogenital diaphragm


- Penile (spongy) urethra is surroundedby erectile tissue - the corpusspongiosum.




Female:


Urethra is surrounded by fibrousconnective tissue




Towards the exterior


Epithelium of the urethra changes as you approach the exterior- transitional, stratified columnar, stratified squamous.

functions and components of male repro system

Functions


• production of spermatozoa


• production of male sex hormones




Components


- testes (seminiferous tubules (production) , straight tubules (transport), rete testis (transport))


- extratesticular ducts (efferent ductules (trasnport), epididymis (maturation, storage and trasnport), ductus deferens aka vas deferens (storage, transport, and forceful expulsion), ejaculatory duct (transport and forceful expulsion, urethra (transport and forceful expulsion))


- glands (seminal vesicles (sperm maintenance), prostate glands (sperm maintenance), bulbourethral glands (lubrication))


- penis

Scrotum temp regulation

Temperature regulation of testes. Normal spermatogenesis
requires 2-3°C lower temperature than core body temperature.
This is achieved in 3 ways: 

1.   dartos muscle of the scrotal skin 

2.   cremaster muscle in spermatic cord 
 •   ...

Temperature regulation of testes. Normal spermatogenesisrequires 2-3°C lower temperature than core body temperature.This is achieved in 3 ways:




1. dartos muscle of the scrotal skin




2. cremaster muscle in spermatic cord


• elevates testes on exposure to cold & during arousal


• warmth reverses the process




3. pampiniform plexus of the spermatic cord


• returning venous blood cools the incoming arterialblood. This is a heat exchange unit.

Components of male repro

1. Testis - seminiferous tubules (sperm production) straight tubules (transport) rete testis (transport)




2. Ducts - efferent ductules (transport) epididymis (maturation, storage and transport) ductus deferens (storage, transport and forceful expulsion) ejaculatory duct (transport and forceful expulsion) urethra (transport and forceful expulsion)




3. Glands - seminal vesicles (sperm maintenance) prostate gland (sperm maintenance) bulbourethral glands (lubrication)




4. Semen - a mixture of sperm and glandular secretions




5. Penis

cross section through spermatic cord

 A low power transverse section of the spermatic cord. The outer cremaster muscle can be
seen enclosing the inner mass of adipose tissue which contains section of the ductus
deferens (lower left) and the pampiniform plexus.

					
				
			
...

A low power transverse section of the spermatic cord. The outer cremaster muscle can beseen enclosing the inner mass of adipose tissue which contains section of the ductusdeferens (lower left) and the pampiniform plexus.

testes componetns

• Paired oval glands measuring ~5cm by2.5cm. Around each wraps the head,body and tail of the epididymis.




• Surrounded by dense white connectivetissue capsule called the tunicaalbuginea. The TA forms a thickening called the mediastinum.


– connective tissue septa form 200 -300 compartments called lobules.




• Each lobule is filled with 1 to 4 seminiferous tubules in which sperm are formed.




• All the seminiferous tubules drain via straight tubules to the rete testis which is located in an area of thecapsule called the mediastinum.


seminiferous tubules

• coiled, non-branching closed loop


• both ends open into rete testis (system of channels) via straight tubules in mediastinum


• about 50 cm long


• seminiferous tubules comprise 70-80% of testicular mass -> testicular volume can bean index of spermatogenesis (measured through ultrasonography)

Histological structure of adult testis

Spermatogenesis

• Spermatogonium (stem cells) give rise to 2daughter cells by mitosis




• One daughter cell kept in reserve -- otherbecomes primary spermatocyte.




• Primary spermatocyte goes throughmeiosis I (this is heat sensitive)


– DNA replication


– tetrad formation


– crossing over (significance?) - unique cells that are not recognised by self, so the blood-testis barrier stops contact with the immune system.


– primary spermatocytes are present inthe tubule for long periods


– These cells have a 2n chromosomenumber but they have double theamount of DNA (duplex chromatidchromosomes)




• Secondary spermatocytes are formed


– 23 chromosomes (n) of which each is 2chromatids joined by centromere. Theytherefore have double the requiredamount of DNA.


– goes through meiosis II


secondary spermatocytes are only present in seiniferour tubules for a brief period, therefore wont see the on microscope.




• 4 spermatids are formed


– each is haploid (n) & unique


– all 4 remain in contact withcytoplasmic bridge


– accounts for synchronized release ofsperm that are 50% X chromosome &50% Y chromosome

Pre puberty section of testes (dont remember)

Compartments of seminiferour tubule

Spermatogenic cells migrate from the peripheral (basal compartment)
to the central part (adluminal and eventually luminal compartment) of

					
				
				
					
						seminiferous tubule.

Spermatogenic cells migrate from the peripheral (basal compartment)to the central part (adluminal and eventually luminal compartment) of seminiferous tubule.

Identify cells fo spermtogenesis on H&E

timing of spermatigenesis

74 days for spermatogonium -> spermatozoon




12 days fro spermatozoon to pass though ductus epididymis and ductus deferens.




The Seminiferous tubules have different stages of spermatogenesis occuring at once -> allows fro a constant production of sperm.

functions of sertoli cells

• secretory factors regulate spermatogenesis and activity of Leydig cells


• secrete tubular fluid, androgen binding protein (ABP), activin, inhibin


• ABP-androgen complex maintains high level of androgens arounddeveloping spermatogenic cells (~200x circulating level)


• phagocytose spermatid excess cytoplasm (residual body)


• assist in spermatogenic movement of sperm and in spermiation




Sertoli cells are


• somatic cells (2n) (called the chromosomal compliment) (important for exam)


• post-mitotic after puberty


• extend from the BM to lumen

blood-testis barrier

 •  tight junctions between Sertoli cells; membranous adhesions; divides
seminiferous tubules into: 
      •  basal compartment – spermatogonia and early primary spermatocytes 
      •  adluminal compartment – differentiating s...

• tight junctions between Sertoli cells; membranous adhesions; dividesseminiferous tubules into:


basal compartment – spermatogonia and early primary spermatocytes


adluminal compartment – differentiating spermatocytes and spermatids

spermiogenesis and spermiation

• Transformation of around spermatid to anelongated spermatid to amature spermatozoon




• Includes developmentand formation of:


• Acrosome


• Flagellum


• Mid-piece with helicalmitochondria


• Highly condensedchromatin


• Species-specific nuclearshape


• Shedding of excesscytoplasm as residualbody

strucuture of mature sperm

 • Head – highly condensed chromatin (protamines
instead of histones) and acrosome (enzymes) 

• Tail
    - Neck = connecting piece powering the flagellum
    - Middle piece (Midpiece)

						outer dense fibres, mitochondria 
   ...

• Head – highly condensed chromatin (protaminesinstead of histones) and acrosome (enzymes)




• Tail


- Neck = connecting piece powering the flagellum


- Middle piece (Midpiece) outer dense fibres, mitochondria


- Principal piece concentric ribs of fibrous sheath , in a 9 + 2 arrangement of microtubules


- End piece

Leydig cells (Intertitial cells of leydig)

 In intertubular (interstitial space)
space, close to blood and lymphatic
vessels 

 • secrete testosterone which diffuses into
seminiferous tubules and systemic
circulation 

• activity controlled by: 
- luteinising hormone (LH) [or
...

In intertubular (interstitial space)space, close to blood and lymphaticvessels




• secrete testosterone which diffuses intoseminiferous tubules and systemiccirculation




• activity controlled by:


- luteinising hormone (LH) [orinterstitial cell-stimulating hormone(ICSH)] which stimulates testosteroneproduction


- prolactin which induces expression ofLH receptor




Histology


Ultrastructure (EM appearance)


• Typical features of steroid-producingcells


• Lipid droplets


• Large amounts of sER


• Mitochondria with tubular cristae




Structure (LM appearance)


• Generally round acidophilic cells(sometimes appear to have foamycytoplasm – lipid droplets that are washedaway)


• Acidophilic due to lots of sERmembranes and mitochondria


• Close to blood vessels

Hormone regulatino of repro system

Inhibin from Sertoli cells– negativefeedback on FSH secretion




Activin from Leydig and Sertoli cells– positive feedback on FSH secretion




Testosterone required for


• development and maintenance ofmale sexual characteristics (bothprenatally and pre-, peri- and post-puberty)


• normal functioning of prostate glandand seminal vesicles (seminal fluid)


• normal functioning of Sertoli cells


• libido

Straight tubules aka tubuli recti (TR

• short terminal segment of seminiferous tubule 
• simple cuboidal epithelium 
• Sertoli cells only, apical tight junctions

					
				
			
		
	


 At this stage, spermatozoa show some
vibratory movement, no forward motility    ...

• short terminal segment of seminiferous tubule


• simple cuboidal epithelium


• Sertoli cells only, apical tight junctions




At this stage, spermatozoa show somevibratory movement, no forward motility

Rete testis

• located in highly vascular mediastinum 
• simple cuboidal epithelium, microvilli, single
cilium 
• reabsorption of protein from testicular fluid 
•  myoid cells – aid movement of sperm

• located in highly vascular mediastinum


• simple cuboidal epithelium, microvilli, singlecilium


• reabsorption of protein from testicular fluid


• myoid cells – aid movement of sperm

Efferent Ductules

12-20 efferent ductules 
Most of the testicular fluid secreted in seminiferous tubules
is reabsorbed in efferent ductules.

					
				
			
		
	


Characteristics
• highly coiled 
• irregularly shaped lumen due to different
heights o...

12-20 efferent ductules


Most of the testicular fluid secreted in seminiferous tubulesis reabsorbed in efferent ductules.




Characteristics


• highly coiled


• irregularly shaped lumen due to differentheights of epithelial cells


• tall columnar ciliated cells


• short cells bearing microvilli - reabsorbfluid


• basal cells – stem cells


• smooth muscle


• ciliary action and muscular contractiontransport sperm along ductules

Ductus epididymis

Efferent ductules join together to form asingle epididymal duct




Epididymal duct


• extremely convoluted, 5m in length


• transit time – 1 week → 12 days


• epididymis (crescent-shaped structure):head (caput epididymis), body (corpusepididymis) and tail (cauda epididymis)






Function


• maturation of spermatozoa –acquisition of new surface proteins,ability to fertilise oocyte


• development of motility


• temporary storage in tail region of duct




Epithelium


- pseudostratified columnar epithelium with stereocilia (microfilaments)


- has secretory and absorptive functions




Types of cells in the epididymalepithelium


• Principal cells bearing immotile stereocilia


- absorb excess fluid


- phagocytosis of degenerate spermatozoa


- secretion of glycoproteins – maturation of sperm


• Basal cells


• Intraepithelial lymphocytes




Smooth muscle


• 1 (proximal) to 3 layers (distal)


• spontaneous, intrinsic contraction in headand body regions


• sympathetic innervation in distal end –intense contraction during ejaculation

Caput epididymis vs Cauda epididymis

Ductus deferens

Ductus (vas) deferens enters abdomenas a component of spermatic cord






Contents of spermatic cord


• ductus deferens (vas deferens)


• spermatic artery


• pampiniform venous plexus


• lymphatic plexus


• nerve fibres


• cremaster muscle




Arterial blood is cooled bycountercurrent heat exchange withvenous blood.




*Site for male surgical “permanent” Ductus deferenscontraception (vasectomy)




Pseudostratified columnar epithelium – resembles epithelium lining tail of epididymisSmooth muscle


• inner and outer longitudinal, middle circular


• sympathetic innervation – strong peristaltic contraction during ejaculation

Ampulla

Ampulla – distal, dilated portion of ductus deferens (2)
Connects with duct from seminal vesicle (5), forms ejaculatory duct (3)

Ampulla – distal, dilated portion of ductus deferens (2)Connects with duct from seminal vesicle (5), forms ejaculatory duct (3)

Seminal Vesicle

• highly folded mucosa


• secretes up to 85% of seminalfluid


• alkaline fluid containing fructose, prostaglandin, fibrinogen


- • Fructose – major source of energyfor ejaculated sperm)


- • Prostaglandin – promotes spermmotility (+other effects)


- • Fibrinogen – clots the semen in theupper reaches of the vagina (fornices)


• normal function dependent ontestosterone






Glandular epithelium


• simple columnar / pseudostratifed columnar epithelium – highly folded


• lipid droplets – foamy appearance under LM


• sperm may be present within lumen – identification




Muscularis


• indistinct smooth muscle layers - inner circular, outer longitudinal


• sympathetic innervation

Prostate Gland

• mucosal glands empty directly into urethra 
•  submucosal and main prostatic glands empty into urethral
(prostatic) sinus, lateral to urethral crest

					
				
			
		
	


         30-50 branched tubuloalveolar glands 
  •...

• mucosal glands empty directly into urethra


• submucosal and main prostatic glands empty into urethral(prostatic) sinus, lateral to urethral crest




30-50 branched tubuloalveolar glands


• Simple columnar / pseudostratified columnar epithelium


• Tall columnar secretory cells and keratin-expressing basal cells






Secretory product


• acidic watery fluid


• contains citric acid, hydrolytic enzymes(e.g. fibrinolysin), Prostate SpecificAntigen (PSA), prostatic acid phosphatase


• normal function dependent ontestosterone




Prostatic concretions


• lamellated glycoprotein masses


• may become calcified


• increases with age




Stroma


• dense collagen fibres


• smooth muscle fibres - sympatheticnervous system

Ejaculatory Ducts

•   Formed by the junction of the ampulla of the ductus deferens and
the duct from the seminal vesicles 
 •   2 ejaculatory ducts empty into the prostatic urethra 
 •   Quite rare to find them in a section

• Formed by the junction of the ampulla of the ductus deferens andthe duct from the seminal vesicles


• 2 ejaculatory ducts empty into the prostatic urethra


• Quite rare to find them in a section

Segments of urethra in male

• pre-prostatic – associated with internal urethral sphincter (retrograde ejaculation)


• prostatic – transitional epithelium; receives sperm and glandular secretions


• membranous – shortest, surrounded by inner smooth and outer skeletal muscle


• penile – longest, surrounded by corpus spongiosum (erectile tissue)-> glans penis

Cross section of penis

• Corpus cavernosum 
• Corpus spongiosum = corpus cavernosum urethrae 
• Tunica albuginea = dense fibroelastic tissue; surrounds each erectile body

• Corpus cavernosum


• Corpus spongiosum = corpus cavernosum urethrae


• Tunica albuginea = dense fibroelastic tissue; surrounds each erectile body

Erectile tissue

 • vascular lacunae – lined by endothelium 
• fibroelastic tissue containing smooth muscle 
• Corpus spongiosum – more connective tissue,
less turgid

• vascular lacunae – lined by endothelium


• fibroelastic tissue containing smooth muscle


• Corpus spongiosum – more connective tissue,less turgid

Penile urethra

 • variable epithelium – transitional/
pseudostratified columnar/stratified
squamous 
• paraurethral glands - lubrication

• variable epithelium – transitional/pseudostratified columnar/stratifiedsquamous


• paraurethral glands - lubrication

What are helicine arteries



	
		
		Helicine arteries supply blood to the sinuses /lacunae
in erectile tissue

Helicine arteries supply blood to the sinuses /lacunaein erectile tissue

What is in semen

• spermatozoa, seminal fluid• includes desquamated cells and other cellular debris• each ejaculate - 40 to 150 million spermatozoa/ml

Ovarian cycle

1. follicular phase (days 1-13)


2. Ovulation (day 14)


3. Luteal phase (day 15-28)




**In reality the cycle is much longer.


from primordial -> multilaminarprimary follicle takes 290 days -> Graafian follicle takes >60 days -> then the dominant follicle is selected from these prepared antral follicles.

Ovary overview

Germinal epithelium called Mesothelium = simple cuboidal epithelium.




Tunica albuginea of dense CT




At the hilum ovarian arteries enter and


at medullar helecine arteries enter




The cortex has primordial and developming ovarin follicles.




There is a stroma containing smooth muscle that surrounds these follicles.




primary oocytes arrested at prophase of meiosis 1 before puberty. At puberty cell cycle continued until arrested again at metaphase of meiosis 2. Waits to be ovulated

Foliculogenesis

primordial


-> primary: single layer of granulosa cells, also stoma organised now into theca interna and externa seperated by a BM. This can become a multilamina 1˚ follicale and the granulosa layer turns into zona pellucida made of glycprotein secreted from oocyte and/or granulosa cells. Begin making theca int and ext








-> secondary (antral F): still has a 1˚ oocyte, it has a F Antrum contain fluid secreted from granulosa cells (that have now formed zona granulosa). Theca int and ext develop more:




Theca internas- cuboidal - progesterone and oestrogen precursors- well vascularised. - have LH receptors.




Theca externa- spindle shape strome cells. - help anchor the follicle to the stroma.




-> graafian (still antral follicle): now has corona radiata a circle of cell directly surroundinf the ZP. Also the cumulus oophorus develops (connects the CR to Z glomerulosa), the FA increases in size, now meisosis continued to metaphase of meiosis 2, LH surge causes ovulation.


-> ovulation: surge of lutenising Hormone from the pituitary gland in response to increasing levels of oestrogen. This causes Ovulation. The surge also stimulates oocytes to continue dev into 2˚ oocytes stopped at metaphase of meiosis 2. During each ovulation 20 follicles mature but only 1 ovulated the rest are lost to atresia. This is why there are <2 million oocytes at birth and only ~300k remaining by puberty with only ~500 oocytes ovulated over lifetime. So atretic follicles are a normal sight.




primordial + primary = preantral (gonadotropin independent)


Secondary and graafian = antral (gonadotropin dependent)




one vulated corpus leteum laft behind. This secretes hormones -> if not fertalised -> this degenerates to corpus albicans.



Corpus Luteum

Angiogenesis around remaining graafian follicel after ovulation turns it into a corpus haemorrhagicum -> then Z granulosa and theca interna cells multiply and form granulosa lutein and theca luteins cells, the resulting structure is the corpus luteum.




Now an endocrine organ, Granulosa lutein cells release progesterone and oestrogen, theca lutein cells release progesterone and androstenedione. This organ continues producing for 10-14 days, if no fertilisation -> degenerates into corpus albicans

Regions of uterine tube

Infundibulum -> ampulla (identify exreemely folded nature, fertilisation occurs here) -> isthmus (reducting in complexity of mucosa epithelium) -> intramural portion

Uterine tube cell types

ciliated columnar cells - aid movement


secretory or peg cells - nourish and protect oocyte.

What maintains the activity of the uterine epithelium?

oestrogen, it stimulates ciliogenesis.

Uterus layers

Endometrium (epithelium, glands, stroma wit not much CT fibres) -> Myometrium (smooth muscle) -> Perimetrium (serosa inf or adventitia superiorly)





Endometrium

divided into:




1. functional layer (outer) - stratum functionalis


2. Basal layer - stratum basale

What causes changes in the endometrium?

Hormones control




1. proliferative phase (d 1-5) - oestrogen from ovarian follicles


2. secretory phase (d 6-15) - progesterone from corpus luteum


3. Menstruation (d 15-d28)




If fertilsation occurs the CL is maintained.





Proliferative phase

The endometrium regrows (due to oestrogen from granulosa cells of growth follicles in ovary) from stratum basal which remains after menstruation.


- epi grows out from gland remnants


- cells have microvilli and cilia


- some straight tubular glands with cellular stroma between


- this endometrium that thickens




During later prolif phase


- increased lvls of oestrogen -> increased # of glands, mitosis of the cells in epi


- epithelial cells becomes columnar


- thickening.




At end of prolif phase


- small amount of oedema


- some glands begin coiling


- thickened depth

Secretory phase

• mostly controlled by the secretionof progesterone from the corpusluteum.




• In summary, the endometriumglands develop further (becomecoiled) and begin to secrete so as toprovide a ‘lush’ and nutrient richenvironment for the possibleimplantation of a zygote.




• Remember ovulation occurs onday 14, fertilisation within 1 to 2days and implantation some 4 to 6days later.

menstruation

schemia – constriction of blood vessels(spiral arteries)Tissue break downBlood vessels rupture Menses (menstrual discharge)• stroma• blood• contains anti-coagulant• 50-100 ml Menarche - first menstruationAmenorrhea - noneMenorrhagia - excessive bleedingDysmenorrhea - painful

Myometrium

• 3 indistinct layers:


• transverse, oblique, longitudinal


• connective tissue (collagen produced by smoothmuscle cells)


• pregnancy causes hypertrophy and hyperplasiaof the smooth muscle


• responsive to oxytocin during parturition (birth)

Cervix

Constricted opening between the uterusand vagina. Has an external and internalos.




Cervical canal (endocervix) tends to havea simple columnar epithelium whichchanges to a stratified squamous(ectocervix) as we approach the vagina.




The viscosity of the glandular secretions ofthe cervix change with the cycle. Thesecan be tested with the Spinnbarkeit test.






The size, consistency and shape of the cervix changes over the female lifespan. Thiscan be caused by menarche, pregnancy and menopause.




Junction from endocervix and ectocervix to squamocolumnar epi of endocervix. ake biosy from heree.

Cervical glands

• deep branching furrows• mucus secreting• consistency of mucus changes with menstrual cycle. Why?• no sloughing of endocervical mucosa during menstruation• fewer smooth muscle cells, more dense connective tissue.• the structure of the collagen changes during childbirth.

Vagina

  A muscular tube lined by an epithelium of stratified squamous epithelium. 
 •  after puberty -> high glycogen content in epithelium 
• metabolised by native flora of Lactobacillus-> lactic acid 
• this creates an acid environment. to...

A muscular tube lined by an epithelium of stratified squamous epithelium.


• after puberty -> high glycogen content in epithelium


• metabolised by native flora of Lactobacillus-> lactic acid


• this creates an acid environment. to prevent abnormal growth of things (BAC, etc)


• many lymphocytes in lamina propria




• No muscularis mucosa or glands• Lamina propria - fibroelastic CT• Indistinct inner circular, outerlongitudinal muscle layers • Adventitia

Mammary glands

 Areola
Nipple 

Mammary glands are modified apocrine sweat glands 
- Lobe – lactiferous duct and its secretory units 
- Connective tissue 
 - Adipose tissue 
 - Suspensory ligaments (cooper's ligaments)

 Initial development at pubert...

AreolaNipple




Mammary glands are modified apocrine sweat glands


- Lobe – lactiferous duct and its secretory units


- Connective tissue


- Adipose tissue


- Suspensory ligaments (cooper's ligaments)




Initial development at puberty under the influence of prolactin, oestrogens and progesteronefrom the developing ovaries (GnRH, FSH and LH)




Changes seen in breast tissue froma nonpregnent to pregnant woman.


The changes are initiated byprolactin, placental lactogen (hCS


- equivalent to growth hormone),oestrogens and progesterone fromthe corpus luteum and theplacenta.


Oestrogen causes development ofthe duct system.


Progesterone cause developmentof the alveolar secretory portion.

Inactive breast

• lobules present but not obvious 
• more ducts than secretory
portions
 • interlobular connective tissue 
• adipose tissue obvious

• lobules present but not obvious


• more ducts than secretoryportions


• interlobular connective tissue


• adipose tissue obvious

Active mammary gland

  Pregnancy 
 •  Interlobular septae obvious, with little fibroelastic CT between lobules 
•  Secretion is stimulated by prolactin, inhibited by high levels of progesterone and
oestrogen. 
•  Milk ejection is stimulated by oxytocin (m...

Pregnancy


• Interlobular septae obvious, with little fibroelastic CT between lobules


• Secretion is stimulated by prolactin, inhibited by high levels of progesterone andoestrogen.


• Milk ejection is stimulated by oxytocin (myoepithelial cells) - suckling.


• Colostrum – low fat content, high protein, maternal antibodies


• Nursing continues the release of prolactin


• Lactational amenorrhea

Cells in the mammary glands

• Secretory cells – cuboidal or columnar


• Myoepithelial cells


• Plasma cells – lactating mammary glandsecrete the secreted form of immunoglobulinIgA into breast milk

Secretions of mammary gland

• Protein – merocrine secretion


• Milk lipids – apocrine secretion

Lactating mammary gland