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404 Cards in this Set

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  • Back
What layers make up the mucosa of the GI tract?
Lamina Propria with reticular fibers.
Muscularis mucosa - unique smooth muscle made of 2 layers
Composition of submucosa?
Loose CT with lots of Type I collagen.
What comprises the muscularis externa?
Lips to upper 1/4 of esophagus (skeletal muscle)
From here to rectum is smooth muscle.
What are the pacemaker cells of the enteric nervous system?
The intestitial cells of Cajal.
What stimulates serotonin release in the GI tract and what does it do?
Released from APUD cells in response to increased intraluminal pressure, vagal stimulation, anaphylaxis, acid in duodenum, Nepi and Ach exposure.
It binds to neurons in the ENS plexi and increases motility.
How does peristalsis work (neurotransmitters)?
Neurons proximal to the food bolus release substance P and Ach to stimulate contraction of the inner circular smooth muscle.
Those distal to the bolus release VIP and NO to relax the muscle.
What is the lining of the oral cavity?
Soft spots are wet epithelium.
Hard palate and gingiva are stratified squamous parakeratinized (masticatory mucosa).
Tongue is wet epithelium with lingual papilla (projections of mucosa and lamina propria).
Why is the vermillion border of the lips pink?
Because the capillary loops are very close to the translucent epithelium. KNOW: Lots of nerve fibers.
What does the sulcus terminalis do in the tongue?
It separates the anterior 2/3rds (body) from the posterior 1/3rd.
What are few things to know about lingual papilla?
Parakeratinized epithelium
No taste buds
Tactile sensation through CN V.
What are few things to know about fungiform papilla?
Each has 5 taste buds innervated by CN VII.
Lined by wet epithelium.
Things to know about vallate papilla?
Stands for trench.
Forms the V-shaped sulcus terminalis.
Ducts of von Ebner's glands empty into trench (lingual lipase).
Lined by wet epithelium.
Innervated by CN IX.
What is the ultrastructure of the taste hair found in the taste cells?
Microvilli with taste receptors
What is the mechanism of the 4 different taste receptors?
Salty - Na channel
Sour - H channel
Sweet, Umami, Bitter - G protein linked.
What are the 3 germ layers of the tooth?
Enamel is ectoderm derived tooth cap.
Dentin is neural crest derived tooth center (mesenchyme).
Cementum is covering tooth root and is mesoderm derived (mesenchyme).
True/False Teeth are avascular?
True, all 3 layers are the same as bone but avascular. The pulp cavity provides blood supply and nerves.
What cell makes dentin?
Odontoblasts deposit dentin through appositional growth.
What is the periodontal ligament?
Dense fibrous CT btw cementum and bone. It anchors the tooth into the alveolus.
Name the type of joint in teeth?
What attaches the gingiva to the enamel?
What makes enamel and how is it interesting?
Ameloblasts make enamel before the tooth has erupted. Once it erupts, the cells die and you can never make more enamel.
Hardest substance in the body due to almost all being hydroxyapatite.
What makes cementum?
The cementocytes that sit in lacuna like bone osteocytes.
Lining of palate?
Superior surface: Resp. mucosa (Pseudostratified ciliated).
Inferior surface: Strat. squam. parakeratinized
Product and germ layer of origin of salivary glands?
Parotid - ectoderm, only serous.
Submandibular - endoderm, mixed serous/mucus with more serous.
Sublingual - endoderm, mixed but mostly mucus.
Difference btw intercalated and striated ducts?
Intercalated ducts are lined by simple cuboidal and connect acinus to striated.
Striated are lined by simple columnar and are main ducts. have basal infoldings for Na/K pumps and Aldosterone works here.
What duct does Aldosterone work on?
The striated duct.
Composition of saliva?
Amylase, lactoferrin, secretory IgA and lysozyme.
What is Waldeyer's ring?
The lingual, palatine and pharyngeal tonsils form a ring of lymphatic tissue around the oropharynx.
Lining of oro and laryngopharynx?
Wet epithelium
Lining of esophagus?
Wet epithelium with Langerhans cells
What are the differences in the esophageal wall compared to rest of GI tract?
Muscularis mucosa is only 1 longitudinal layer.
Submucosa has esophageal glands proper or cardiac glands closer to stomach.
Muscularis externa is sk. muscle in upper 1/3, both sk and sm muscle in middle 1/3 and bottom 1/3 is smooth muscle.
Stomach lining?
Simple columnar surface mucous cells (NOT GOBLET CELLS)
Where are gastric pits found? What are the regions and what is found in each region?
Found in the lamina propria of the stomach.
Gastric pit - lined by surface mucous cells.
Isthmus - Lined by parietal cells.
Neck - Mucous neck cells and basal stem cells.
Base - Chief cells and APUD cells
Where are the stem cells in the fundic glands, what do they replace and what stimulates them?
Found in the neck region and replace all cells of stomach lining.
Gastrin and EGF stimulates their proliferation
Where are the parietal cells? What special cell structures do they have?
Neck and base of fundic gland.
Intracellular secretory canaliculus during active secretion.
Tubulovesicular system which contains H/K ATPase
Sequence of HCL production?
1) CO2 enters basal side, forms HCO3 and H. 2) HCO3 exchanged on basal side for Cl. 3) Cl leaks out apical PM due to negative RMP. 4) Protons (from CO2) are pumped out apical PM in exchange for K. 5) K leaks out both basal (to regenerate negative RMP) and apical side (to run H/K ATPase).
Stimuli for HCL production?
1) ACh and gastrin (through Ca 2nd messenger)
2) Histamine from APUD/mast cells (works paracrine through H2 receptor - cAMP 2nd messenger)
Inhibitors of HCl production?
1) Tagamet and Zantac - H2 receptor blockers
2) Prilosec - H pump inhibitor
3) Somatostatin (produced by stomach APUD cells)
Why are aspirin and ibuprofen bad for your stomach?
They block COX1 and COX2 required to make PGE2 which is protective lining for the stomach. Lower PGE2 causes stomach ulcers and cancer.
Why does Vioxx not cause stomach problems like aspirin?
It only blocks COXII. Blocking COXI causes stomach problems because it prevents formation of PGE2 which is a protective lining for the stomach.
What 2 things do parietal cells make?
HCl and GIF
Where are the chief cells found and what do they do? What are the stimuli for their function?
In base of fundic glands.
Produce pepsinogen for breakdown of protein.
Also produce gastric lipase.
Histamine, gastrin and Ach stimulate release of pepsinogen.
What are the 5 hormones made by the DNES system of the gut?
CCK, secretin, gastrin, GIP and motilin.
What is different about the stomach muscularis externa?
3 layers instead of 2 (additional layer is inner oblique)
What forms the common mucosal barrier?
Tight junctions of stomach surface mucous cells and mucous lining.
Is the mucous produced by the mucous neck cells and surface mucous cells neutral or basic?
Neutral but HCO3 produced by parietal cells enters the mucous from the fenestrated capillary loops that run into villus.
What is Ghrelin?
Hormone released by stomach. Is increased by fasting and decreased by feeding.
What are the 3 phases of digestion?
Cephalic phase - see, smell or think of food. CNS increase PS to increase HCl, pepsinogen, mucous and gastrin.
Gastric phase - increased stretch or decreased pH causes increased secretion through gastrin and histamine and increased motility.
Intestinal phase - Increase fatty acids and glucose in SI inhibit gastric emptying and motility through CCK and secretin. Secretin decreases HCl and CCK inhibits gastric emptying.
What factors increase gastric emptying?
Stomach distention and gastrin
What factors decrease gastric emptying?
Duodenum distention.
Fats, carbs and aa's in duodenum.
Increased chyme osmolarity.
Increased chyme acidity.
Where would you find plicae circularis?
Permanent folds of the mucosa and submucosa of the SI.
What 4 cells do you find in the intestinal villus?
Surface absorptive cells
Goblet cells
APUD cells
M cells
What do the crypts of Lieberkuhn do?
They are mucosal glands in the SI that secrete cells. The stem cells of the crypts replace the surface absorptive cells, goblet cells, APUD cells and Paneth cells.
What do Paneth cells secrete?
Lysozyme, TNF-a and defensins
Where do you find Brunner's glands? Function?
In the submucosa of the duodenum with a duct emptying into the crypts. They make alkaline mucus to line the SI, they inhibit HCl production and make EGF for crypt stem cell stimulus.
Where is EGF made and what does it do?
Made in the Brunner's glands, it stimulates stem cells in both crypts of Lieberkuhn and in the neck portion of the gastric gland to divide.
What 2 locations of the GI tract have submucosal glands?
The esophagus has esophageal glands proper. The duodenum has Brunner's glands.
What is different between Ileum and Duodenum?
The villi are shorter as you move distal and the goblet cells are highest in ileum. Ileum also has Peyer's patches (lymph tissue).
Where would you find plicae semilunaris?
Difference btw LI and SI?
In LI - No villi, no paneth cells but still have crypts.
What are the taenia coli?
Bunched outer longitudinal muscularis externa
What are the 3 epithelial linings of the anal canal?
Rectum - pectinate line - external anal orifice
Simple columnar to strat. squam. non-keratinized to strat. squam. keratinized.
Germ layer of pancreas acinar cells and method of secretion?
Endoderm derived and the zymogens are released into intercellular secretory canaliculi.
What enzymes does the pancreas release?
Trypsinogen, chymotrypsinogen, procarboxypeptidase, proelastase, p. amylase, p. lipase, deoxyribonuclease and ribonuclease
Why can't you see the lumen of the pancreatic acinus?
Because the intercalated duct cells are pulled into lumen to form centroacinar cells.
What is the target of secretin in the pancreas?
Intercalated ducts cells (make HCO3-)
Pancreatic cancer is mainly a _______ problem, whereas pancreatitis is a ________ problem?
Duct cell
Acinar cell
Histologically, the quadrate and caudate lobes of the liver belong to ______?
The left lobe
Primary fibers of liver parenchyma?
Reticular fibers
What are the 5 structures of the porta hepatis?
HPV, HA, Autonomics, Lymphatics and L/R hepatic ducts
What does the portal area in the liver consist of?
Limiting plate surrounds the terminal portal venule, terminal hepatic arteriole, bile ductule, lymphatic capillary and nerve branches.
Difference btw portal triad and portal area?
Portal triad is TPV, THA and BD.
Add the CT, nerves, periportal space of Mall and the limiting plate to form portal area.
What blood does the sinusoid of the liver carry?
Hepatic portal vein and hepatic artery blood mix in the sinusoid and drain into the central vein.
What connects the THV to sinusoids through limiting plate? What about bile?
Inlet venule
Canal of Hering (first true bile duct)
Lining of hepatic sinusoids?
Endothelial cells with pores but no diaphragms. Kupffer cells sit inside lumen (macrophages).
What is found in the space of Disse?
Tissue fluid, nerve fibers, fibroblasts, reticular fibers and hepatic stellate cells.
What do the hepatic stellate cells do? What stimulates them during pathological conditions?
Store Vitamin A and lipid.
In pathological conditions, they make type I collagen, laminins and fibronectin which leads to fibrotic condition of cirrhosis.
Kupffer cells release cytokines which stimulate the collagen production. The stellate cells are called myofibroblasts at this point.
Similarity btw pancreas exocrine secretion and liver exocrine secretion?
Both hepatocytes and acinar cells release the product into intercellular secretory canaliculi.
Can liver hepatocytes divide?
Yes, but usually don't
What 3 cell junctions do hepatocytes have?
Gap junctions and desmosomes where they connect to one another. Tight junctions at the intercellular secretory canaliculi
Where does lymph in the liver begin?
Begins in the space of Disse from left over filtered plasma. Drains into the periportal space of Mall.
Where does secretory IgA in bile come from?
Plasma cells in SI lamina propria make IgA which goes to liver and hepatocytes take it up and make secretory IgA which is secreted into bile.
Discuss zones of liver acinus?
Based on diamond shape of blood flow.
Zone 1: Most 02, most metabolically active, active glycogen and plasma protein synthesis.
Zone 2
Zone 3: Lowest O2, closest to central vein, site of drug and alcohol detox and very vulnerable to ischemia.
What changes can occur in Zone 3 of the liver acinus?
Too much alcohol - fatty
Person on barbiturates - SER increases.
Malnutrition, ischemia, drug or chemical toxicity - centrilobular necrosis.
What lines the gallbladder?
Simple columnar epithelium
What forms the blood bile barrier?
Tight junctions of the gallbladder epithelium so that cells can reabsorb H20 and ions.
Discuss the salivary gland secretion?
Acinar cells use electrogenic Cl secretion to secrete water, amylase and mucous.
The duct cells use electrogenic Na absorption but instead of Cl through paracellular flow, it uses a Cl/HCO3 exchanger. K is also secreted (probably to account for Na positive charge).
How does saliva differ btw times of meals and rest times?
During meal times, saliva flow is fast through the duct. HCO3 exchanger can keep up but Na/K can't so pH is high but osmolarity is similar to ISF.
During rest times, saliva flow is slower so HCO3 can be heavily secreted and Na reabsorbed leaving a very hypotonic solution with high pH.
Why do you want a hypotonic alkaline saliva?
Hypotonicity kills bacteria. pH prevents acid erosion of teeth and also kills bacteria.
What do prevacid, prilosec and nexium do?
They are proton/K pump inhibitors in the stomach
Discuss pancreatic acinar cell secretion?
Uses normal electrogenic Cl secretion but also releases vesicles of zymogens in the process.
Discuss pancreatic duct secretion?
HCO3 is secreted in a similar way to salivary duct secretion. There is a HCO3/Cl exchanger but also a HCO3/Cl cotransporter. IMPORTANT: H20 moves into the lumen through paracellular flow.
To rid the cell of excess protons generated during HCO3 production, there is a Na/H exchanger in the basolateral membrane.
How are fructose, glucose and galactose absorbed in the GI tract?
Fructose has it's own GLUT5 transporter in the apical surface.
Glucose/galactose are moved through apical surface via secondary active transport with 2 Na (SGLT1) and then through basolateral side through GLUT2 transporter.
How does the LI absorb water?
1) Na is absorbed with almost all nutrients which creates an osmotic gradient.
2) There is a Cl/HCO3 exchanger and a Na/H exchanger in the apical membrane which also creates an osmotic gradient by absorbing NaCl.
3) The LI uses electrogenic Na reabsorption as well.
What is considered upper respiratory system vs. lower respiratory system?
Upper: Nasopharynx, nasal cavity and oropharynx.
Lower: Larynx, trachea, bronchi and lungs
What is considered conducting system of respiratory pathway? Lining epithelium?
Nose to terminal bronchioles
Respiratory epithelium (pseudostratified ciliated).
5 cells of the respiratory conduction system? Function
Goblet cells: mucous
Ciliated columnar cells: Mucociliary escalator.
Basal cells: Stem cells replacing ciliated, brush and goblet cells.
Brush cells: Columnar cells with microvilli, no known function.
DNES cells: Release paracrine substances
Lining of nasal cavity?
Nostrils and vestibule - thin skin (strat. squam. keratinized).
Rest of nasal cavity is respiratory epithelium.
Explain blood flow of nasal cavity?
Blood flows posterior to anterior and air flows opposite so it is a countercurrent heat exchanger.
Swell bodies are venous plexi in erectile tissue of nose. Increase blood flow into these every 1/2 hour or so which increases blood flow here and cavity swells shut to allow for rehydration.
What are glands in lamina propria of nasal cavity called?
Seromucous glands which moisten the air and blend with the periosteum of bone to form mucoperiosteum.
What are the 3 cell types of the olfactory epithelium? Structure and function?
1) Olfactory receptors - bipolar neurons with bulbous projection on 1 of the axons. This bulbous projection has non-motile cilia which have receptors for smell. The nuclei are in the middle of the pseudostratified epithelium and the axons projecting to the CNS are unmyelinated.
2) Supporting cells - nuclei located in apical portion of pseudostratified epithelium.
3) Basal cells - stem cells of epithelium
Where are the glands of Bowman and what do they do?
In the lamina propria of the olfactory mucosa. They secrete lysozyme, secretory IgA and OBP (odorant-binding protein)
How do the olfactory receptors work?
Found on the non-motile cilia, they are G-protein linked. Odorant binds and increases cAMP which opens Na channels.
Lining of paranasal sinuses?
Mucoperiosteum with seromucous glands and respiratory epithelium.
Difference btw true vocal cords and false?
True: Inferior, sk. muscle, wet epithelium (below is respiratory epithelium).
False: Superior, loose CT with seromucous glands lined by wet epithelium.
What does the trachealis do?
Connects the tracheal C-shaped rings to each other and narrows the lumen for fast airflow. This allows for coughing.
What are the 3 layers of the trachea?
Pseudostratified ciliated epithelium, fibroelastic CT with seromucous glands and adventitia (comprised of C-shaped rings).
5 changes that occur as we move down bronchial tree?
Diameter decreases
Cartilage decreases and smooth muscle increases
Elastic fibers increase
Cilia # and height decreases
# of glands decreases
Characteristics of 1, 2 and 3 bronchi?
Primary: Cartilage is circular, right trifurcates and left bifurcates.
Secondary: Branches to each lobe.
Tertiary: Branches to 10 bronchopulmonary segments.
Characteristics of intrapulmonary bronchi?
Cartilage is plates of hyaline.
Sm. muscle is btw lamina propria and submucosa like muscularis mucosa. It is a spiral muscle though.
What do conducting bronchioles supply? What lines them? Other characteristics?
Supply a primary lobule. Lined by simple columnar epithelium.
Prominent smooth muscle layer is here.
Which tube of respiratory tree has prominent smooth muscle?
The conducting bronchioles.
Where do histamines, leukotrienes and prostaglandins work on the respiratory system?
In the conducting bronchioles causing bronchiolar constriction.
At what level does the respiratory system lose goblet cells?
The terminal bronchioles (still has cilia)
Characteristics of terminal bronchioles?
Lose goblet cells.
Lined by simple cuboidal ciliated epithelium.
Clara cells are found here.
Where are Clara cells first found and what do they do?
First found in terminal bronchioles.
Produce surfactant like substance, lysozyme, protease inhibitors and proteolytic enzymes.
Are also the stem cells for the epithelium.
What are the stem cells for the terminal bronchioles called?
Clara cells.
What is the last tube of the conducting portion of the respiratory system?
Terminal bronchiole.
Characteristics of respiratory bronchioles?
Lined by simple cuboidal with few cilia.
Some clara cells.
Alveoli found on 1 side, pulmonary artery found on the other side.
What are the primary fibers in the alveoli?
Elastic fibers (some reticular fibers)
What is the purpose of the pores in the interalveolar septa?
To allow pressure equalization
Why is the primary pathology in emphysema?
Elastase destroys the CT of the lung because liver production of a-1 antitrypsin is decreased.
Can type I pneumocytes divide? What cell-cell junctions do they have?
Tight junctions to prevent fluid seepage
What cell do the type II pneumocytes replace? Can they divide? What do they do?
The Clara cells
Make surfactant
Where is surfactant stored and what is it made of?
Composed of dipalmitoyl phosphatidylcholine (DPPC) and stored in lamellar bodies of type II pneumocytes.
What do dust cells do?
Macrophages in the lungs that phagocytose dust and bacteria. Also make elastase to breakdown elastic fibers. When they are full, they crawl to mucociliary escalator where they are taken away.
What are the 4 layers that gas must pass through in order to get into blood?
Type I pneumocyte
Fused basal lamina
The capillaries found in the lung are __________?
Where do the blood vessels in the lung run?
Pulmonary artery branches run with bronchiolar arteries next to bronchioles.
Pulmonary veins run in CT septa.
Germ layer of origin of neuro and adenohypophysis?
Neuro (posterior pituitary) - NEURAL ECTODERM
Adeno (anterior pituitary) - ECTODERM
What covers the pars distalis?
Dura mater as an outer capsule with reticular fibers.
The capillaries found in the pars distalis are?
Sinusoidal capillaries
What is a chromophobe vs a chromophil?
Both are found in the pars distalis.
Chromophobe is an inactive chromophil away from capillaries.
Chromophils lie next to the capillaries and are either acidophils or basophils.
Which hormones come from basophils vs. acidophils?
Acidophils - GH and prolactin
Basophils - Fsh, Lh, Tsh and Acth.
Where are the 2 sets of sinusoidal capillaries?
In the hypothalamus and anterior pituitary
Where are the cell bodies of the pars nervosa neurons located? Myelinated or unmyelinated?
Multipolar neurons in the supraoptic and paraventricular nucleus.
What are Hering bodies?
Swellings along the axons of pars nervosa neurons. They contain ADH, oxytocin, ATP, neurophysin I (oxytocin) and neurophysin II (ADH)
What are neurophysins in the posterior pituitary?
Carriers of ADH and oxytocin in the preprohormone form.
Origin of oxytocin and ADH?
Oxytocin comes from paraventricular nucleus.
ADH comes from supraoptic nucleus.
Why are there nuclei in the neurohypophysis?
Because of the pituicytes (astrocytes)
What kind of capillaries are found in the posterior pituitary?
What is the other name for ADH?
Arginine vasopressin (AVP)
Germ layer of origin of thyroid gland?
Discuss the 4 steps of thyroid hormone production?
1) Tyrosine enters follicle from blood side, converted into thyroglobulin.
2) TSH stimulates iodide uptake and oxidation by thyroidal peroxidase (TPO).
3) Iodine and thyroglobulin exocytosed into lumen. Microvilli enzymes iodinate tyrosine residues on thyroglobulin.
4) MIT and DIT formed, then added to form T3 and T4.
Discuss 3 steps of thyroxine release?
1) TSH binds receptors on basal surface of cell causing endocytosis of lumenal thyroglobulin with MIT, DIT, T3 and T4 attached.
2) In cytoplasm, T3 and T4 are liberated from thyroglobulin. 90% of product is T4 but T3 is active hormone.
3) T3/T4 increases BMR, HR, growth, temperature and enhances cell function.
What is difference btw T3 and T4?
90% of thyroxine is T4 but T3 is the active hormone.
What is endocrine product of thyroid? What is exocrine?
Endocrine is T3,T4.
Exocrine is thyroglobulin and iodine.
What type of capillaries are found in the thyroid gland?
Where are the parathyroid glands derived from?
3rd and 4th pharyngeal pouches - ENDODERM
2 types of cells in parathyroid gland? Functions?
Chief cells - Secrete parathyroid hormone
Oxyphil cells - Function unknown, stain acidophillic due to mitochondria
Types of capillaries located in the parathyroid glands? Primary fibers in stroma?
Reticular fibers
What is the sequence of Vit. D activation?
Cholecalciferol from skin goes to liver where it is hydroxylated to form 25-Hydroxy cholecalciferol. This goes to the kidney where PTH stimulates 1-a hydroxylase to form 1,25-Dihydroxy cholecalciferol. 1,25-Dihydroxy cholecalciferol goes to the intestines and stimulates the formation calbindin to increase Ca uptake.
How does parathyroid hormone affect Vit. D activity?
PTH stimulates 1-a hydroxylase to hydroxylate 25-hydroxy cholecalciferol to 1,25-Dihydroxycholecalciferol in the kidney.
Germ layer of origin of the adrenal cortex and medulla?
Cortex - Mesoderm
Medulla - Neural crest
What type of capillaries are found in adrenal cortex?
Sinusoidal capillaries (5 places total)
What is a spongiocyte and where is it found?
Spongiocytes are adipocytes found in the adrenal cortex. Their function is to store cholesterol.
What 2 cells are found in adrenal medulla?
Chromaffin cells
Ganglion cells
Pathway for formation of Epi?
Tyrosine -- DOPA (Tyrosine hydroxylase).
DOPA -- Dopamine (Dopa decarboxylase)
Dopamine -- Nepi (Dopamine hydroxylase)
Nepi -- Epi (Phenylethanolamine N-methyl transferase)
What enzyme is required to form Epi?
PNMT - Phenylethanolamine N-methyl transferase
How does the adrenal medulla distinguish between making Epi vs. Nepi?
Amount of corticosteroids reaching the chromaffin cells controls PNMT.
If blood reaches the cells through the medullary arteriole then it doesn't pick up any corticosteroids and Nepi is formed.
If blood goes through sinusoidal capillaries it picks up lots of cortisol which stimulates PNMT to make Epi.
Why is the fetal adrenal cortex important?
Because it produces the precursors for estrogen formation by the placenta. If the baby dies then levels of estrogen in the mom's urine drops.
Germ layer of origin of pancreatic islets of Langerhans? What type of capillaries does it contain?
What are the 4 types of cells in the pancreas and what do they release?
B cells - Center of islet and release insulin.
a cells - At periphery and produce glucagon.
D cells - At periphery and produce somatostatin.
What do pancreatic polypeptide cells do?
Release pancreatic polypeptide to inhibit the exocrine secretion of the pancreas.
What are the 5 hormones increasing BGL?
The pineal gland capsule is actually ______ and the primary stromal fibers are?
The pia mater
Reticular fibers
What is corpora arenacea and where is it found?
Brain sand (CaCO3 crystals) found in the interstitium of the pineal gland.
What are the cells in the pineal gland called and what do they secrete?
Serotonin by day, Melatonin by night.
What is the stimulus for melatonin production?
Absence of light on retina sends the following pathway -
Retina to hypothalamic suprachiasmatic nucleus to thoracic spinal cord to superior cervical ganglion to post sympathetics to B adrenergic receptors on pinealocytes.
What enzyme is required for melatonin production?
HIOMT - Hydroxyindole-O-methyltransferase
Difference btw prohormone and preprohormone?
Preprohormone has a signal peptide that gets it to the ER. Prohormone occurs after the signal peptide is removed.
What is the prohormone for oxytocin, AVP and insulin?
Neurophysin I
Neurophysin II
What are the 2 alterations that prohormones undergo during processing?
Prohormones are cut at basic residues by carboxypeptidase E.
Peptidylglycine-a-amidating monooxygenase (PAM) amidates the C-terminus of the prohormone.
What is pro-opiomelanocortin (POMC)?
A prohormone for a number of different hormones like ACTH and MSH.
What do the enzymes PC1 and PC2 cut POMC into?
PC1 cuts ACTH out of POMC.
PC2 cuts numerous places to yield MSH, LPH (lipotropin), ACTH or CLIP (corticotropin like intermediate peptide).
What is the prohormone for B endorphins?
What test would you run to differentiate between Cushing syndrome and disease?
Administer dexamethasone, monitor ACTH levels. If they are unchanged then Cushing Disease. If cortisol levels remain high then Cushing's syndrome.
What are the 4 types of Diabetes Insipidus?
Nephrogenic: Non-responsive ADH receptors.
Gestational diabetes: Develops during pregnancy.
Dipsogenic: You drink too much water.
Neurogenic: NO AVP from posterior pituitary.
Treatment for neurogenic or gestational diabetes insipidus?
Cause of neurogenic diabetes insipidus?
X-linked/AD familial neurohypophyseal diabetes insipidus.
When does neurogenic diabetes insipidus first present?
At 9 months when mom is no longer supplying AVP in milk.
Steps of thyroid hormone synthesis?
1) Thyroglobulin made from tyrosine and extruded into lumen. 2) Iodine/Na pump moves iodine into cell from blood. 3) Iodine is oxidized by thyroidal peroxidase on apical microvilli and added to thyroglobulin. 4) MIT and DIT are coupled to form T3 or T4 and stored in lumen.
What enzyme oxidizes Iodine for thyroxine production?
TPO (Thyroidal peroxidase)
Steps of thyroid hormone release?
1) TSH binds on basal side and increases cAMP. This induces thyroglobulin uptake from colloid. 2) T3 and T4 are stripped off of thyroglobulin and extruded into blood. 3) MIT and DIT are deiodinated and the cycle repeats.
How are T3 and T4 broken down?
T4 is broken down equally into T3 and reverseT3. These are deiodinated to diiodothyronine which is conjugated with glucuronides and excreted in bile. Most of the diiodothyronine is recycled and excreted by the kidney.
Steps of catecholamine synthesis?
1) Tyrosine transported into neuron through tyrosine/Na channel. 2) Tyrosine is converted into DOPA through tyrosine hydroxylase (rate-limiting). 3) DOPA is converted into dopamine through DOPA decarboxylase. 4) Dopamine is packaged into vesicles (reserpine). 5) Nepi is formed in vesicles by dopamine hydroxylase.
What do metyrosine and reserpine do?
Metyrosine is an inhibitor of tyrosine hydroxylase blocking catecholamine synthesis and Reserpine blocks dopamine vesicle channels.
What do you use Bretylium and Guanethidine for?
Bretylium is used to reduce VTACH/VFIB. Guanethidine is an antihypertensive. Both prevent the release of Nepi.
What cofactor is needed for tyrosine hydroxylase?
Where does SAM fit into catecholamine synthesis?
SAM is needed to methylate NEpi while PNMT catalyzes the reaction.
Name 2 activators of tyrosine hydroxylase and 3 inhibitors?
cAMP and Ca activate it.
Dopamine and Nepi inhibit through negative feedback.
Metyrosine inhibits it.
How are catecholamines broken down?
COMT methylates an OH group on the benzene ring and then MAO deaminates the product for excretion.
Causes of Parkinson's disease?
Encephalitis infection
Toxins: MPTP, methanol, CN
Drugs: Reserpine, phenothiazines, butyrophenone.
Treatment for Parkinson's
LDOPA with DOPA decarboxylase inhibitor such as Carbidopa.
Pergolide or Bromocriptine which are dopamine agonists.
What would you use Pergolide or Bromocriptine for?
Dopamine agonists for treatment of Parkinsons.
Rate limiting step for serotonin and melatonin synthesis?
Trp hydroxylase
What is Hartnup's disease? Symptoms and Treatments?
AR defect in trp transporter in kidney and SI.
Symptoms: Photosensitive dermatitis, neuro symptoms, blue diaper syndrome (due to indole ring in feces).
Treatment: Trp-trp dipeptide which is taken up by a different transporter.
What are organophosphates and how would you treat their effects?
Organophosphates are irreversible ACHE inhibitors (insecticides and sarin gas). They phosphorylate ACHE.
Prophylactic pyridostigmine can be used.
Atropine, Diazepam and Pralidoxime can be used post-exposure.
How does pralidoxime work?
It is used to dephosphorylate ACHE which was phosphorylated by organophosphates
What are the functions of the 4 histamine receptors?
H1 - Sm muscle, endothelium and CNS tissue. Causes vasodilation, bronchoconstriction and allergic rxn symptoms.
H2 - Stimulates/regulates HCL secretion in the stomach.
H3 - Decreases nt release (Ach, Nepi and serotonin)
H4 - Function unknown.
What enzymes are required for histamine synthesis and break down?
Aromatic L-amino acid decarboxylase.
Histamine-N-methyltransferase and diamine oxidase.
What is the mechanism for the H1 receptor of allergic reaction?
Gq receptor (HAV 1 M&M) which increases IP3 and DAG causing Ca release. This activates smooth muscle, causes vasodilation and bronchoconstriction.
What do Diphenhydramine, Fexofenadine and Loratidine have in common?
Diphenhydramine (Benadryl), Fexofenadine (Allegra) and Loratidine (Claritin) are all H1 receptor blockers - Antihistamines.
Benadryl causes drowsiness because it crosses the BBB and binds H1 receptors in the sleep center.
How is nitric oxide synthesized?
Nitric oxide synthase converts Arginine into NO and Citrulline
Name 3 activators of NO formation and 1 inhibitor?
ACH, Bradykinin and Cytokines.
How do Sildenafil and Tadalafil work?
Sildenafil (Viagra) and Tadalafil (Cialis) block cGMP phosphodiesterase causing prolonged cGMP. DO NOT CREATE cGMP so can't start an erection, just prolong it.
What are iloprost and cisoprost used for?
Synthetic PGI2 drugs which treat Raynaud's phenomenon.
What are the 7 layers that air must move through in order to get into blood?
Type I pneumocyte
Fused basal lamina
Endothelial cell
RBC membrane
RBC intracellular fluid
What are average numbers for TV, IRV, ERV, RV?
TV = 500ml
IRV = 2500ml
ERV = 1500ml
RV = 1500ml
Which volumes and capacities cannot be measured by spirometry?
What is FEF?
Forced midexpiratory flow.
Rate of airflow over middle half of FVC.
What changes are seen with obstructive lung disease?
FEV1/FVC < 70
FEF slope decreased
Increased TLC (hyperinflated lungs)
Decreased blood flow
Decreased static recoil of lung
Decreased pulmonary diffusion
Examples of parenchymal and extraparenchymal lung diseases?
Parenchymal - changes in alveolar walls or septa such as inflammation, fibrosis and alveoli destruction. Subcategory is interstitial lung disease which is caused by fibrosis, sarcoidosis and decreased surfactant.
Extraparenchymal - problems with chest wall, respiratory muscles and CNS drive. Examples: Polio, ALS or MG. Pneumothorax.
Signs of parenchymal lung disease?
Decreased lung volumes
Decreased TLC, VC, RV, DLCO2, PaO2
PCO2 is normal
Signs of extraparenchymal lung disease?
Decreased TLC, VC, FRC
RV increased because muscles can't compress chest
Normal DLCO2
PaO2 decreased and PaCO2 increased.
Main differences btw parenchymal and extraparenchymal lung disease?
Parenchymal: RV decreased, PaO2 decreased, PaCO2 normal and DLCO2 decreased.
Extraparenchymal: RV increased, PaO2 decreased, PaCO2 increased, lung compliance and DLCO2 fine
How does prednisone treat asthma?
It increases the production of lipocortins which block phospholipase A2. PLA2 is required to form arachidonic acid which is used to form leukotrienes which exacerbate asthma.
Similar precursors to Cortisol, Aldosterone and DHEA formation?
Cholesterol to Pregnenolone.
Cortisol and DHEA then go Pregnenolone to 17-OH Pregnenolone.
DHEA is formed from 17-OH Pregnenolone.
Cortisol goes from 17-OH Pregnenolone to 17-OH Progesterone to 11-Deoxycortisol.
Aldosterone is the least like the others. From Pregnenolone it goes to Progesterone and then to 11-Deoxycorticosterone, Corticosterone and then to Aldosterone.
What is the main difference in structure btw Cortisol, Aldosterone, Corticosterone and DHEA?
Cortis(ol) has another OH
Corticosterone has 1 additional ketone
Aldosterone has 2 additional ketones
DHEA has OH right off the Imidazole ring.
What is found in the renal sinus?
Renal artery and vein
Renal pelvis, minor and major calyces
What makes up the renal pyramids?
Collecting ducts, Loops of Henle and Vasa recta
What is the renal lobule composed of?
A central medullary ray with cortical labyrinth on either side.
Interlobular arteries separate lobules on either side.
What is the renal cortex made up of?
Renal corpuscles (labyrinth), PCT and DCT, medullary rays, peritubular capillaries and renal columns.
Difference btw cortical and juxtamedullary nephrons?
Cortical: Renal corpuscle in middle/outer portion of cortex. Very short loop of Henle.
JM : Corpuscle at junction of cortex and medulla. Loop of Henle is ridiculously long.
What is the sequence of blood vessels from renal artery?
RA - Anterior/posterior segmentals - interlobar arteries - arcuate arteries (corticomedullary jxn) - interlobular arteries - afferent/efferent arterioles.
Where is Epo released from?
Peritubular capillary endothelium.
Why is the GBM really not a basement membrane and what is it's ultrastructure?
It is really 2 fused basal lamina with 2 lamina rara and 1 lamina densa. The densa contains type IV collagen and the rara contain heparan sulfate.
What makes up the blood urine barrier?
Fenestrated capillary endothelium, fused basal lamina and podocyte pedicels.
Which part of GBM acts as a size filter vs. a charge filter?
Size filter is lamina densa with type IV collagen.
Charge filter is lamina rara with heparan sulfate.
What do mesangial cells do and what receptors do they have to do this?
Control blood flow through glomerulus with actin and Angiotensin II receptors.
Phagocytose macromolecules stuck in the GBM.
Make growth factors and inflammatory mediators like IL-1 and prostaglandins.
Are mesangial cells able to divide?
Lining of PCT? Function?
Low columnar/cuboidal with tight junctions and brush border microvilli.
Reabsorb 80% NaCl, 65% H2O, 100% glucose and aa's.
Lining of Loop of Henle? Function?
Thin parts: simple squamous
Thick parts: cuboidal
Descending limb permeable to Na and H2O, makes interstitium hypertonic.
Ascending limb impermeable to H2O so tubule becomes hypotonic.
Lining of distal tubule? Function?
Low cuboidal with microvilli but not brush border.
Forms macula densa for NaCl regulation.
Regulates Na/K, NH4 and H levels.
What are the 2 cell types of the DCT? What hormones do they respond to?
Principle cells - Do Na/K exchange, respond to Aldosterone and ANP.
Intercalated cells - Secrete H and control urine pH.
Lining of the collecting ducts? Function?
Cuboidal early on, columnar down at papillary ducts.
Under control of ADH, reabsorb last amounts of H2O and control pH.
Where are most of the intercalated cells in the kidney located?
In the collecting duct.
What proteins are expressed in the collecting ducts in response to ADH?
AQP2, AQP3 and AQP4
Lining of renal papilla?
Transitional epithelium
What accounts for half of the renal medullary interstitium osmolarity?
50% Urea
How does the juxtaglomerular apparatus work?
Macula densa cells detect [NaCl] in the distal tubule and if it is high, stop releasing NO to cause vasoconstriction of afferent arteriole.
JG cells are in afferent arteriole wall and release renin in response to low BP.
Lacis cells coordinate the actions between macula densa and afferent arterioles.
5 functions of Ang II?
Stimulate ADH from hypothalamus
Stimulate thirst center
Stimulate zona glomerulosa for aldosterone
Stimulate PCT Na reabsorption.
Interesting about ureter walls?
Muscularis layers are opposite: outer circular, inner longitudinal.
Lined by transitional epithelium
What forms the blood urine barrier in the bladder?
Tight junctions and desmosomes of the transitional epithelium
Interesting thing about bladder muscularis?
3 layers and called the detrusor muscle.
Lining of male urethra? Female?
Prostatic portion: transitional.
Membranous portion: Stratified columnar.
Penile portion: Stratified columnar.
Female: Stratified squamous.
Pressures that Halm uses for GFR?
Pgc = 60mmHg
Pbc = 20mmHg
Tc = 31mmHg
How are most substances reabsorbed in the PCT?
Using secondary active transport coupled to Na reabsorption. The basal Na/K pumps create a gradient for apical Na absorption.
How is glucose absorbed in the PCT?
Early PCT is SGLT2 glucose:1Na transporter. Late PCT is SGLT1 which is same as SI glucose:2Na transporter. This is so that very low [glucose] can occur in PCT.
What are the main transporters in the thick ascending limb?
Apical surface has NKCC2 channel and outward directed K leak channel. Basal surface has Cl/K outward directed cotransporter and Cl leak channel.
Difference btw transluminal potential of thick ascending limb versus PCT?
In PCT, the blood becomes positive whereas in the ascending limb, lumen is positive.
How does furosemide work?
It is a loop diuretic and blocks the NKCC2 pump in the ascending limb.
How does ouabain work?
Na/K pump inhibitor. In the kidney, it blocks the basolateral Na/K pump inhibiting reabsorption.
Absorption method of the early DCT?
Apical Na/Cl cotransporter allows for electroneutral NaCl absorption.
Where do thiazide diuretics block?
Block Na/Cl cotransporter in the apical PM of the distal tubule.
What channels do the principle cells of the DCT have?
Basically channels required for electrogenic Na reabsorption except additional K leak channel in apical membrane.
How do aldosterone and amiloride affect the DCT?
Amiloride blocks the Na/K exchange.
Aldosterone increases the number of Na channels in the apical membrane for electrogenic Na absorption.
What channels do the intercalated cells of the DCT have?
H ATPase to secrete H on the apical side.
Cl/HCO3 exchanger on the basal side as well as Cl leak channel.
What makes closed and open buffers better?
Closed buffers are best when pH = pKa and there is a lot of buffer.
Open buffers are better as the pH of the solution gets higher or lower depending on acid or base.
What layers cover the ovary?
Germinal epithelium (low cuboidal) is from mesothelium. Mesovarium is peritoneum covering this and tunica albuginea is below germinal epithelium.
Most ovarian cancer is of ______ origin?
Germinal epithelium
Germ layer of origin for ovaries?
Everything is mesoderm except germ cells (oocytes) which are endoderm. Even the follicular cells are mesoderm.
When does oogenesis start in a female?
Begins during fetal life. THERE ARE NO OOGONIA AT BIRTH.
At what stage do oocytes arrest?
The dictyotene stage of Meiosis I.
Describe a primordial follicle?
Single layer of squamous follicular cells around primary oocyte (46 4n). Oocyte suspended at dictyotene stage of meiosis 1.
Describe a unilaminar primary follicle?
Surrounding follicular cells are cuboidal and only 1 layer of cells. Oocyte still 46 4n
Describe a multilaminar primary follicle?
Stratified layer of follicular cells now called granulosa cells. Oocyte still 46 4n.
Is stratum granulosum vascular or avascular?
When are the cortical granules and zona pellucida first visible in the oocyte PM?
At the multilaminar primary follicle stage.
What are the important compositions of the zona pellucida?
ZP3 receptor with O-linked sugars.
Microvilli of oocyte with gap junctions to filopodia of granulosa cells
Is the theca interna vascular or avascular and why is it like this?
Theca interna cells make an angiogenesis factor.
What is the ultrastructure of the theca interna cells?
Have LH receptors
Look like steroid producing cells with lots of SER, tubular mitochondria and lipid droplets.
What is the product of the theca interna cells?
What do the granulosa cells make and what enzyme does this require?
Estrogen from Androstenedione (supplied by theca interna cells). Cytochrome P450 aromatase is required.
When do you call the follicle a secondary follicle?
When follicular fluid spaces begin to develop in the granulosa layer.
Describe an early antral follicle?
LH receptors on theca interna cells inducing androstenedione production. FSH receptors on granulosa cells stimulating their proliferation and production of estrogen through aromatase enzyme.
Fluid filled follicular spaces developing.
Primary oocyte (46 4n).
Describe a late antral follicle?
Only difference btw early and late is now LH receptors are found on granulosa cells as well.
What causes LH receptors to be expressed on granulosa cells?
Estrogen produced by the granulosa cells and FSH stimulation of granulosa cells indirectly.
What are the 2 important hormones of the follicular fluid?
Activin - stimulates FSH release.
Inhibin - inhibits FSH release.
Describe a mature Graafian follicle?
Large fluid filled antrum.
Granulosa cells covering oocyte called cumulus oophorus.
Single layer of granulosa cells called corona radiata.
Gap junctions still intact btw corona and oocyte.
Stigma of ovary develops ready for ovulation.
Still primary oocyte (46 4n)
What converts the primary oocyte into the secondary?
LH surge causes release of meiosis inducing substance.
7 steps of ovulation?
Cumulus mass breaks up
Gap jxns are lost
1st meiotic division completed
Hyaluronic acid and proteoglycans build up in antrum attracting H20 and loosening up stratum granulosum.
LH surge increases blood flow to theca externa leading to edema. Histamine, prostaglandins and collagenase are released.
Ischemia causes blanching and stigma formation.
Stigma ruptures and 2 oocyte released.
Cells of the corpus luteum? Function?
Granulosa lutein cells - take on steroid producing characteristics and produce Progesterone (some estrogen)
Theca lutein cells - Produce mainly estrogen (some progesterone).
What normally maintains the corpus luteum and w/o it, what is it's lifespan?
14 days
What forms corpus albicans?
Fibroblasts invade and deposit CT.
What is the last thing to degenerate of an atretic follicle?
The zona pellucida
What is found in the ovarian medulla?
Epitheloid interstitial cells which make estrogen.
What is the cell in the ovary equivalent to the interstitial cell of Leydig?
The hilus cell because it makes androgens. Tumors can occur here leading to masculinization
Lining of oviduct? Differences btw infundibular end and uterine end?
Simple columnar ciliated epithelium and peg cells
More peg cells at the uterine end and ciliated cells at the infundibular end.
What is the product of a peg cell and what stimulates it's release?
Estrogen stimulates the release of nutrients from the peg cell and factors to capacitate the sperm.
What stimulates the formation of cilia on the oviduct epithelium?
What stimulates peristalsis of the muscularis layer of the oviduct?
What is the serosa of the oviduct called?
What receptors does the uterine myometrium have and what is the effect?
Estrogen receptors which causes hypertrophy and hyperplasia
Difference between myometrium of uterus and cervix?
Uterine myometrium is 3 muscle layers (inner and outer longitudinal and middle circular).
The myometrium of the cervix is DICT with elastic fibers.
Lining of uterus? Predominant fiber type in LP?
Endometrium is simple columnar epithelium (some secretory, some ciliated).
Few fibers in LP but mostly reticular.
2 subdivisions of uterine endometrium and supplying blood vessels?
Stratum functionalis shows changes during cycle and supplied by the spiral arteries.
Stratum basalis does not show changes and is supplied by straight arteries.
Composition of cervical LP vs. uterine LP?
Dense CT with loads of elastic fibers
DICT with few fibers mostly reticular fibers.
Lining of cervix?
On canal side, mucus secreting simple columnar.
On fornix side, wet epithelium
Function of relaxin?
Causes lysis of collagen fibers in cervix and pubic symphysis during parturition.
What do the cervical glands produce?
Mucus and lysozyme
What does cervical mucus look like during proliferative and secretory phases?
Proliferative - watery
Secretory - thick
What region of the cervix does the pap smear involve?
Fornix wet epithelium
What is the most variable phase of menstrual cycle?
The proliferative phase of the uterus (follicular phase of ovary)
What hormone is highest during the proliferative phase vs. the secretory phase?
What do the glands of the uterus look like during the proliferative phase?
Straight, smooth and glycogen is in the basal cytoplasm of the cells.
Days of the proliferative, secretory and menses phases?
Proliferative 5-14
Early secretory 15-24
Late secretory 25-28
Menses 1-4
Happenings in the early secretory phase?
Edema causes thickening of functionalis.
Glycogen moves from basal cytoplasm to apical.
Glands begin to spiral, become tortuous and sacculated.
Happenings of late secretory phase?
Referred to as ischemic phase.
Spiral arteries undergo intermittent vasospasms and after 2 days or so become constricted.
What day do estrogen levels peak? What about LH?
Estrogen peaks on day 12.5
LH peaks on day 13.5
What day of cycle does implantation usually occur on?
What is the main function of the cytotrophoblasts?
To proliferate and replace the syncytiotrophoblasts
What is the region of the placenta called where most of the villi are located?
The chorion frondosum and decidua basalis.
What forms the blood-placental barrier?
Basal lamina of trophoblast
CT of villus
Basal lamina of endothelial cell
Endothelial cell
What type of capillaries are located in the villi of the placenta?
Sinusoidal capillaries.
Where do all placental hormones come from?
What hormones does the syncytiotrophoblast secrete?
hCG, progesterone, estrogen, hCS, hCT, relaxin and leptin.
What does the placenta need to make estrogen?
DHEA from the fetal adrenals
Lining of vagina?
Wet epithelium
Effect of estrogen on the vagina?
Stimulates epithelial cells to release glycogen which bacteria use to make lactic acid thereby lowering the pH of the vagina.
What is special about vagina lamina propria?
Has papilla projecting into surface mucosa
Where does the lubricant for the vagina come from?
Vagina does not have glands. Transudate released combines with mucus from cervix resulting in lubrication.
Which cells in males and females make inhibin
Sertoli cells and granulosa cells.
What is the layer of peritoneum covering the testes called?
Tunica vaginalis
Composition of inner and outer capsule of testis?
Tunica albuginea is DICT
Tunica vasculosa is Loose CT.
What type of capillaries are found in the lobules of the testis?
2 cell types of seminiferous epithelium? Which of these replicate and what is their germ layer of origin?
Sertoli cells which are columnar are unable to replicate after puberty - MESODERM
Spermatogenic cells are able to migrate and replicate - ENDODERM.
What receptors are found on sertoli cells?
Name 3 junctions found in the seminiferous epithelium? What stimulates the formation of these junctions?
Sertoli-germ cell junctions - DESMOSOME LIKE JUNCTIONS.
Sertoli-basal lamina junctions - HEMIDESMOSOMES.
Sertoli-Sertoli junctions - GAP JUNCTIONS AND TIGHT JUNCTIONS.
FSH stimulates formation of the tight junctions.
Function of the tight junctions in the seminiferous epithelium and why are they odd?
Establish a basal and adluminal compartment.
Create blood-testis barrier allowing immunologic barrier and ABP/testosterone to be highly concentrated in adluminal compartment.
What are found in the basal and adluminal compartments of the seminiferous epithelium?
Spermatogonia are found in the basal compartment.(MITOSIS).
Spermatocytes and tids are found in the adluminal compartment (MEIOSIS).
4 functions of sertoli cells?
Form blood-testis barrier
Nutritive cells for gametes
Phagocytic cells for residual cytoplasm.
Secretory cells
Name the substances that sertoli cells secrete? Which is most prevalent as an adult vs. fetus?
Testicular fluid, testicular transferrin, ABP, inhibin and AMH.
Adult: Inhibin
Fetus: AMH
What is main difference between germ cells of ovaries vs. testis at birth?
There are no oogonia at birth, all primary oocytes.
Testes however, have all spermatogonia until puberty. Only at puberty do the primary spermatocytes arise.
3 types of cells of spermatocytogenesis?
Type A dark (gonia) - RARELY divide and are reserve cells.
Type A pale (gonia) - Euchromatic nucleus because they divide like crazy.
Both Type A light and dark are self renewing.
Type B (gonia) - NOT SELF RENEWING, differentiate into primary spermatocytes.
Chromosome and DNA content of different sperm cells?
Type B spermatogonia 46 2n
1 spermatocyte 46 4n
2 spermatocyte 23 2n
spermatid 23 1n
(oocytes are the same)
What is spermiogenesis?
Early spermatids into later spermatids. 4 phases: Golgi phase, cap phase, acrosomal phase and maturation phase.
4 phases of spermiogenesis and what happens in each?
Golgi phase: hydrolytic enzymes formed in RER, modified in Golgi, packaged into proacrosomal granules which coalesce to form acrosomal vesicle. Acrosomal vesicle moves to anterior pole while centrioles move to posterior pole to form axoneme of flagellum.
Cap phase: Acrosomal vesicle forms acrosomal cap.
Acrosomal phase: Head points towards BL, nucleus condenses and flattens, mitochondria move to neck region of flagellum.
Maturation phase: Cytoplasmic bridges are lost and residual cytoplasm is phagocytosed by Sertoli cells.
3 enzymes of acrosome?
Acid phosphatase
Where do sperm develop motility?
In the epididymal duct
What moves sperm through the rete testis and efferent ductules?
96% of fluid reabsorbed in efferent ductules creates a fluid flow gradient which along with peristalsis moves sperm
Which salivary gland is composed of completely serous elements?
Where are von Ebner's glands found?
Vallate papillae
What are the peripheral landmarks of the 3 lobules of the liver?
Classic lobule - Portal areas
Portal lobule - Central veins
Liver acinus - Central veins
What are the central landmarks of the 3 lobules of the liver?
Classic lobule - Central vein
Portal lobule - portal areas
Liver acinus - 2 portal areas
First part of the respiratory tract w/o cilia?
Alveolar ducts
First part of the respiratory tract w/o goblet cells?
Terminal bronchioles
Part of respiratory tract where bronchiolar and pulmonary arteries coalesce?
Respiratory bronchioles in order to take part in gas exchange.
Lining of respiratory bronchioles?
Simple cuboidal on one side like terminal bronchioles.
First part of respiratory epithelium w/o seromucous glands?
Conducting bronchioles
Primary fibers of alveoli?
Primarily elastic fibers with some reticular fibers.
Which is more numerous type I or Type II pneumocyte?
Type II more numerous, type I covers more area.
What is the glomerular filtration coefficient?
The term used to substitute hydraulic conductivity and area of glomerular filter. Has to do with Fick's diffusion law.
Which is tight and which is loose (PCT or DCT)?
PCT is loose and leaky
DCT/thick ascending limb are tight.
Why is the lumen positive in the ascending limb?
Due to apical K leak channels
Germ layer of origin of the interstitial cells of Leydig?
What receptors are found on the interstital cells of Leydig? Function?
LH receptors cause the cells to make testosterone.
Which are considered intratesticular genital ducts?
Straight tubules, rete testis, proximal efferent ductules.
Lining of straight tubules of testis?
Proximal - only by sertoli cells. Simple cuboidal lines second half with apical tight junctions.
When do the tight junctions of the seminiferous epithelium revert from basal to apical?
In the second half of the straight tubule when lining goes from Sertoli cells to simple cuboidal.
Lining of rete testis?
Simple cuboidal
Lining of efferent ductules? Function?
2 cells
Tall ciliated columnar and short cells with microvilli (festooned appearance).
96% of testicular fluid is reabsorbed here.
Which are considered extratesticular ducts?
Efferent ductules, epididymal ducts, vas deferens, ejaculatory ducts, urethra.
Lining of epididymal duct?
Lined by pseudostratified epithelium with tall columnar cells and basal cells. Tall columnar cells have stereocilia and basal cells are stem cells.
What do the principle cells of the epididymal duct do?
Have stereocilia to reabsorb fluid. Release glycoprotein and sialic acid which is added to the sperm head.
Also release organic acids to lower the pH which keeps sperm non-motile and quiescent.
Make glycerophosphocoline which inhibits sperm capacitation.
Phagocytose dead sperm and residual cytoplasm.
What happens to epididymal duct throughout it's length?
Epithelial and stereocilia height decreases. Three layers of smooth muscle increase.
Is the smooth muscle of the epididymis head innervated by ANS? What about tail?
Head is not
Tail is innervated by multiunit ANS.
Lining of vas deferens?
What is special about the vas deferens?
It has probably the thickest smooth muscle coat of all vessels (per size)
Lining of ejaculatory duct?
Simple columnar/pseudostratified.
Germ layer of origin of seminal vesicles? Lining?
What controls seminal vesicle development?
What is secretory product of seminal vesicles?
Alkaline fluid containing nutrients and fructose.
Germ layer of origin of prostate gland?
Lining of prostate gland?
Simple columnar
What does DHT do to the prostate gland?
5-a reductase is located in the prostate gland and DHT increases the production and release of prostatic fluid.
Side effects of DHT? Treatments?
Produces benign prostatic hypertrophy and alopecia
Avodart (Finasteride) blocks 5-a reductase
What does the prostate secrete?
Zinc (bactericidal)
Citrate (ATP for sperm)
Acid phosphatase
Prostate specific antigen
Where are the corpora amylacea located?
Concretions in the prostate.
What do bulbourethral glands secrete?
Pre-seminal fluid.
Blood flow to and from penis?
Deep and dorsal arteries break up into helicine and capillary plexi to supply penis.
Drained by deep dorsal vein.
Discuss erection?
PS stimulates release of NO which causes vasodilation of the helicine arteries through cGMP.
AV shunt is constricted during erection diverting blood into penis.
In flaccid state, AV shunt is open.
How does Sildenafil work?
Blocks cGMP phosphodiesterase preventing NO generated effects from ending.
Order of release of ejaculate?
Bulbourethral glands, prostate enzymes, tail of epididymis releases sperm and seminal vesicles add nutrients.
3 events of fertilization?
1) Acrosomal reaction and release of hyaluronidase which dissolves cellular contacts btw corona radiata.
2) Sperm binds ZP3 causing release of acrosin to penetrate ZP.
3) Sperm fuses with oocyte PM inducing Ca influx mediated cortical reaction.
2 components to cortical reaction?
Fast component - RMP of oocyte changes preventing polyspermy
Slow component - Cortical granules released which hydrolyze ZP3 receptors.
5 stages of prophase I?
Leptotene - Telomeres attach to nuclear envelope.
Zygotene - Synaptonemal complex forms which is where chromosomes are joined.
Pachytene - Crossing over occurs
Diplotene - Synaptonemal complex separates but chromosomes still attached by chiasmata
Diakinesis - nuclear envelope disappears
What stage do primary oocytes get stuck at?
Diplotene stage (Dictyotene)
What stage of meiosis is reduction division?
Anaphase I when chiasmata release and homologous chromosomes separate (46 4n to 23 2n).
What stage of meiosis is equational division?
Anaphase II when chromatids move apart. Technically, cell was haploid after meiosis I in which case you are separating 2 copies of 1 gene.
What is the rate limiting step for steroid formation?
Cholesterol to Pregnenolone. Controlled by LH from AP.
Which estrogen form has protective effect?
E3 (estriol) blocks the binding of estrone and estradiol reducing the risk of breast cancer.
Which estrogen form is most abundant and which is strongest?
E3 is most abundant
Strength wise E2>E1>E3
Which region of the ovary accounts for most of the tumors?
Germinal epithelium
What hormone accounts for progesterone receptors on the endometrium?
Do Leydig cells mitose after puberty?
What is the tunica propria?
A fibrous CT sheath surrounding each seminiferous tubule.
What capillaries are found in the posterior pituitary?
What are ketoconazole and metyrapone used for?
Treating Cushing's SYNDROME
What type of G-protein is ACTH and FSH?
Same as betas (Gs)
What type of G-protein is the angiotensin receptor?
Which are PAS positive? Acidophils of Basophils?
Interestingly: Basophils because of glycoproteins.
Where does the processing of prohormones occur? Explain?
In immature secretory granules where carboxypeptidase E cuts at the basic residues and PAM (Peptidylglycine-a-amidating monooxygenase) amidates the C terminus
Lining of lips
Outer - strat. squam keratinized (thin skin)
Vermillion border - parakeratinized
Inner lip - non-keratinized (wet epithelium).