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130 Cards in this Set
- Front
- Back
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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 |
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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 |
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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 wash away taste molecules for new taste and secrete lingual lipase for saliva. |
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What separates the anterior 2/3 of the tongue from the posterior 1/3? |
Sulcus terminalis |
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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) |
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Location of - Gingiva - Enamal of tooth - Dentine of tooth - Pulp chamber of tooth - periodontal membrane - Cementum - root canal of tooth - Vermillion border - Labial sulcus |
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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 give rise the the enamel organs for the other molars. Mesenchyme then condenses to form dental papilla. |
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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. |
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What is a dentine tubule? |
Dentine tubules contain the apical processes of odontoblasts, these cells produce dentin. |
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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. |
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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 |
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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 |
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What is this gland? |
Submandibular gland - mostly serous with some mucous acini displaying serous demilunes (SD), |
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What is this gland? |
Sublingual salivary gland - mucous acini with some serous acini only present as serous demilunes. |
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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. |
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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 |
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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 |
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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. |
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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 there is tunica adventitia. |
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What epithelial change occurs going from oesophagus to stomach? |
SS epithelium -> S cuboidal epithelium. Also the epithelium in the stomach arranges into gland crypts. |
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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. |
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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. |
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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 |
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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. |
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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. |
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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. |
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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 (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. |
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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. |
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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. |
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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 the mucosa by the musculars mucosa. |
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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. |
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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. |
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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. |
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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. |
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appendix |
It is difficult to see due to the MALT but there are colonic mucosa present with glands. |
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Summary of layers across the oesophagus -> colon |
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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 |
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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) where the hepatic portal vein, hepatic artery, lymphatic vessel and bile duct are found. |
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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 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. |
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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. |
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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. |
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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. |
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Adrenal gland cortex |
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 |
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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 - 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. |
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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 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 |
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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. |
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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. |
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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. |
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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. |
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Renal corpuscle appearance |
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. |
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How does the renal corpuscle form? |
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. |
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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. |
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Components of glomerular filtration barrier (membrane): |
• 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 |
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How does the glomerular filtration barrier (membrane) work? |
The negative charge in the BM, the fenestrae diaphragm, the |
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Proximal Convoluted Tubule |
• 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. |
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Loop of Henle |
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 |
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Distal convoluted tubule |
• 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. |
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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. |
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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. |
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From collecting duct to urinary epithelium |
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. |
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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)
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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. |
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Urinary bladder |
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. |
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Urethra: male and female |
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. |
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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 |
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Scrotum temp regulation |
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. |
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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 |
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cross section through spermatic cord |
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. |
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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. |
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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) |
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Histological structure of adult testis |
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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 |
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Pre puberty section of testes (dont remember) |
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Compartments of seminiferour tubule |
Spermatogenic cells migrate from the peripheral (basal compartment)to the central part (adluminal and eventually luminal compartment) of seminiferous tubule. |
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Identify cells fo spermtogenesis on H&E |
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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. |
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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 |
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blood-testis barrier |
• tight junctions between Sertoli cells; membranous adhesions; dividesseminiferous tubules into: • basal compartment – spermatogonia and early primary spermatocytes • adluminal compartment – differentiating spermatocytes and spermatids |
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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 |
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strucuture of mature sperm |
• 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 |
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Leydig cells (Intertitial cells of leydig) |
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 |
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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 |
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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 somevibratory movement, no forward motility |
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Rete testis |
• located in highly vascular mediastinum • simple cuboidal epithelium, microvilli, singlecilium • reabsorption of protein from testicular fluid • myoid cells – aid movement of sperm |
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Efferent Ductules |
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 |
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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 |
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Caput epididymis vs Cauda epididymis |
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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 |
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Ampulla |
Ampulla – distal, dilated portion of ductus deferens (2)Connects with duct from seminal vesicle (5), forms ejaculatory duct (3) |
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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 |
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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 • 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 |
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Ejaculatory Ducts |
• 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 |
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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 |
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Cross section of penis |
• Corpus cavernosum • Corpus spongiosum = corpus cavernosum urethrae • Tunica albuginea = dense fibroelastic tissue; surrounds each erectile body |
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Erectile tissue |
• vascular lacunae – lined by endothelium • fibroelastic tissue containing smooth muscle • Corpus spongiosum – more connective tissue,less turgid |
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Penile urethra |
• variable epithelium – transitional/pseudostratified columnar/stratifiedsquamous • paraurethral glands - lubrication |
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What are helicine arteries |
Helicine arteries supply blood to the sinuses /lacunaein erectile tissue |
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What is in semen |
• spermatozoa, seminal fluid• includes desquamated cells and other cellular debris• each ejaculate - 40 to 150 million spermatozoa/ml |
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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. |
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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 |
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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. |
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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 |
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Regions of uterine tube |
Infundibulum -> ampulla (identify exreemely folded nature, fertilisation occurs here) -> isthmus (reducting in complexity of mucosa epithelium) -> intramural portion |
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Uterine tube cell types |
ciliated columnar cells - aid movement secretory or peg cells - nourish and protect oocyte. |
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What maintains the activity of the uterine epithelium? |
oestrogen, it stimulates ciliogenesis. |
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Uterus layers |
Endometrium (epithelium, glands, stroma wit not much CT fibres) -> Myometrium (smooth muscle) -> Perimetrium (serosa inf or adventitia superiorly) |
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Endometrium |
divided into: 1. functional layer (outer) - stratum functionalis 2. Basal layer - stratum basale |
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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. |
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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 |
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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. |
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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 |
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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) |
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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. |
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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. |
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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 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 |
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Mammary glands |
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. |
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Inactive breast |
• lobules present but not obvious • more ducts than secretoryportions • interlobular connective tissue • adipose tissue obvious |
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Active mammary gland |
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 |
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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 |
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Secretions of mammary gland |
• Protein – merocrine secretion • Milk lipids – apocrine secretion |
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Lactating mammary gland |
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