Final Physiology Exam
4 Examples of chemical alteration by the liver
- Ammonia is converted to urea - Porphyrins turned into bilirubin - Purines are turned into uric acid - Steroids and xenobiotics are altered and then secreted into bile
Describe the role of ADH in response to changes in plasma osmolality
- Osmoreceptors in the hypothalamus, monitor the concentration of solute (osmolality) of blood. -When the blood becomes more concentrated (aka less dilute) such as during increased salt intake or dehydration, the higher osmolality stimulates the osmoreceptors - When osmoreceptors are stimulated, the hypothalamus signals the posterior pituitary gland - The Posterior Pit releases ADH into the bloodstream. - ADH makes the walls of the kidneys distal convoluted tubules more permeable to water. - The increased permeability causes more water to be reabsorbed from the filtrate as it passes through the renal tubules - The reabsorbed water returns to the bloodstream and reduces the concentration of solutes (AKA dilutes blood) which reduces osmolality - Negative feedback turns of this mechanism
Intestinal Contraction Types and motility - What are they - What do they do and how responsible are they for movement in the SI
- Peristalsis: Undulation of the lining to move chyme (Weaker here than in the esophagus and stomach) - Segmentation: Muscular constrictions of the lumen at different intestinal segment (squeezing chyme through) Segmentation is the major contractile mechanism of the small intestine.
Two compartments of the testes - Names and contents
- Seminiferous tubules: Sperm creation happens here. They have FSH receptors - Interstitial tissue: Contain leydig cells which have leutenizing hormone receptors. When they receive LH the secrete testosterone
Functions of the stomach 4
- Stores food - Initiates digestion of proteins - Kills bacteria in the food - Moves food into small intestine
Describe the role of the sympathetic nervous system in the regulation of the glomerular filtration rate.
- low blood pressure activates sympathetic activity - Sympathetic activity causes vasoconstriction of afferent arterioles - Afferent arteriole constriction lowers the glomerular filtration rate (GFR) - Decreased GFR lowers urine production - If less urine is created, more water is retained thus blood pressure and volume is increased
Layers of the uterus (4)
-Endometrium: inner layer, where the embryo implants and develops. This is shed during menstruation -Myometrium: middle muscle layer; contracts to expel baby at birth. -Perimetrium: outer connective tissue layer. -Cervix: narrow bottom region of the uterus.
structures that will eventually produce sperm What are they (3) When do they develop? (2)
-Germinal cells (become sperm) -Sertoli cells (supporting cells) differentiate 43−50 days after fertilization. The Leydig cells: begin making large amounts of testosterone about 8 weeks after ovum fertilization.
Kidneys regulate 4
-Volume of blood plasma (affects blood pressure) -Wastes -Electrolytes -pH
Digestion of starch occurs mainly in the ___ via _______
1. Duodenum 2. Pancreatic amylase
Meiosis 1 and 2 produce
2 spermatids 4 spermatids
How much bile does the liver make every day
250-1500 ml
Reabsorption % of urobilinogen
30-50% is reabsorbed by the intestines and returned to the liver
Secondary Oocytes
A primary oocyte becomes a secondary oocyte after it finishes Meiosis 1. •The secondary oocyte begins meiosis II, but stops at metaphase II. •Meiosis II will complete only if the ovum is fertilized.
Stomach defenses (Why doesn't the stomach digest itself?)
Adherent mucus on the stomach contains a bicarbonate Tight junctions in the epithelia prevent HCl from penetrating into the viscera of the stomach Stomach regenerates its epithelia every 3 days
Describe the relationship between the functions performed by aldosterone and ADH
Aldosterone is released in response to low salt intake. It helps reabsorb sodium into the blood increasing its osmolarity. It is downregulated when salt is prevalent ADH is triggered in response to high sodium levels (or low water). It increases the amount of water retained by the kidneys returning it to the blood, diluting the salt concentration and reducing urine production. It is downregulated when salt is low or water is high
How do the kidneys respond to respiratory acidosis and respiratory alkalosis?
Alkalosis: Less bicarbonate is reabsorbed, thus extra bicarbonate is secreted to compensate for alkalosis. Acidosis: Proximal tubule can make extra bicarbonate through the metabolism of the amino acid glutamine. Extra bicarbonate enters the blood to compensate for acidosis.
How much digestion takes place in the large intestine Does the Large Intestine produce anything?
Almost none. Yes, it produces vitamin K, and fatty acids from undigested polysaccharides, Also produces vitamin B via microbial organisms
Loop of Henle components
Ascending and descending limb
Compare and contrast the roles of the ascending and descending limbs of the loop of Henle in the countercurrent multiplier system.
Ascending limb - sets up an osmotic gradient by actively pumping salt (NaCl) OUT and into the interstitial fluid making the interstitial fluid hypertonic (have more solute concentration so that water moves towards it) Descending limb - is permeable to water and allows water to exit the filtrate
uterine cycle
Begins with menstruation at the end of the previous ovarian cycle. -Menstrual phase -Proliferative phase -Secretory phase
Wolfian and mullerian ducts - Found in
Both male and female embryos
Describe the pattern of circulation in the hepatic portal system
Capillaries in the intestines > veins in the hepatic portal > capillaries in the liver > hepatic vein A double system in which blood diffuses from capillary into a portal vein then from that vein back into a capillary and then back into a hepatic vein (Review this... Anatomy explained it better)
What are bile acids derived from
Cholesterol In fact, the livers production of bile acids from cholesterol is the major pathway of cholesterol breakdown in the body
Urobilinogen - What is it? - What's a notable effect it has
Conjugated bilirubin that has been transported to the small intestine It makes feces brown and urine amber
Pancreatic juice - What does it contain and what are their functions (4)
Contains bicarbonate and 20 digestive enzymes like: 1. Pancreatic Amylase: Digests starch 2. Trypsin: Digests protein 3. Lipase: Digests triglycerides
Spermatogenesis
Creation of sperm. Not maturation
Follicular Phase of Ovarian Cycle
Day 1-14 - The anterior pituitary secretes FSH - FSH stimulates the production of FSH receptors on granulosa cells surrounding oocyte and follicles encapsulating oocyte. This enhances their sensitivity to more FSH - The granulosa cells secrete more estrogen. These levels continue to rise -- peaking around day 12 of the ovarian cycle - The combo of high estrogen and FSH levels stimulate the production of FSH receptors on the Graafian follicle, preparing it for ovulation at which point it will burst expelling a secondary oocyte - The rapid rise in estrogen stimulates the hypothalamus to increase the frequency of FSH and LH (GnRH) pulses. - Increased FSH and LH pulses cause the pituitary to increase LH secretion. Forming a positive feedback loop, which leads to an LH surge -- triggering ovulation
Secretory Phase - Days - Coincides with - What happens
Day 15-28 The secretory phase occurs while the ovaries are in the luteal phase The endometrium becomes even thicker and more vascular in response to increased estrogen and progesterone and it is prepared to nourish a growing embryo if the oocyte is fertilized.
Proliferative Phase - Days - Coincides with - What happens
Day 5-14 The proliferative phase occurs while the ovary is in the follicular phase Stratum functionale of the endometrium grows The endometrium becomes more vascular and develops progesterone receptors.
Menstrual Phase - Days - Coincides with - What happens
Days 1-4 Coincides with the end of the luteal phase and the beginning of the follicular phase The menstrual phase occurs as a result of the fall in estrogen and progesterone when the corpus luteum degenerates at the end of the ovarian cycle Arteries in the endometrium constrict, cells in the stratum functionale die, and this layer is sloughed.
Functions of HCl 3
Denature proteins and aid digestion Activate pepsin to digest proteins Provide the optimal pH for pepsin activity
Functions of the liver (5)
Detox the blood Carb metabolism Lipid metabolism Protein synthesis Secretion of bile
Digestion of fats - Site - What happens - What's involved
Digestion begins in duodenum: bile emulsifies fat while lipase (from pancreas) breaks it down into fatty acids and monoglycerides Phospholipase A (from pancreas) digests phospholipids into fatty acids
2 Functions of the digestive system
Digestion: Breaks down polymers into monomers Absorption: Takes these monomers to the bloodstream
Pepsin - Function
Digests protein
What conditions are diuretics used for clinically?
Diuretics are medications that are used clinically to control blood pressure and relieve fluid accumulation
Pancreas functions Think of ducts
Endocrine: Secrete glucagon and insulin Exocrine: Acini cells secrete pancreatic juice which heads to the duodenum via the pancreatic duct
Describe the digestive tracts built in immune barrier
Epithelia with tight junctions prevents swallowed pathogens from entering body Connective tissue in tract promotes an immune response
Digestive Tract Secretions include? Hint: 2 types
Exocrine: Digestive enzymes, HCl, mucus, water, and bicarbonate Endocrine: Hormones to regulate digestion
What are the three potential filtration barriers in the glomerulus?
Filtration barriers: capillary fenestrae, glomerular basement membrane, slit diaphragm.
Sertoli cells - Found in - Secrete
Found in men secrete Mullerian-inhibiting factor (MIF) which causes regression of the Mullerian ducts. As a result mullerian ducts do not develop into female sex organs
Seminal fluid contains
Fructose for nourishment
G cells secrete
Gastrin
2 Things that stimulate HCl secretion - Mechanisms of action
Gastrin: Stimulates parietal cells directly. But more commonly stimulates ECL cells to make histamine, which stimulate parietal cells to secrete HCl via H2 histamine receptors Parasympathetic neurons: deliver AcH which stimulates parietal and ECL cells
Growth of secondary follicles - What causes it - What does it become
Happens in response to FSH and estrogen, Vesicles fuse to form a single antrum at which point it becomes a graafian
GI submucosa - Function - Characteristic
High vascular Picks up nutrients
Why are diuretics banned by the Olympic committee?
Increase urine output. Hides the presence of performance enhancing drugs.
Gi mucosa - Def
Inner secretory and absoptive layer
Functional amenorrhea
Intense physical exercise, stress, and/or very low body fat (low leptin) limit GnRH secretion which limits the release of LH and FSH As a result menstruation does not occur
Regulation of the GI Tract - Types
Intrinsic and extrinsic Intrinsic regulation comes from the stomach's internal nervous system the enteric nervous system External is the ANS
How can the liver make bilirubin water soluble
It conjugates it with glucuronic acid
Is bilirubin polar or non polar
It is non polar. It requires a carrier protein (normally albumin)
Renal autoregulation - Def - How it works
Kidneys regulate their own GFR even when blood pressure fluctuates Dilate for low blood pres Constrict for high
Describe the mechanism of action of diuretics.
Loop diuretics: most powerful; inhibit salt transport out of ascending loop of Henle -Can inhibit up to 25% of water reabsorption. Thiazide diuretics: inhibit salt transport in the distal tubule. -Can inhibit up to 8% of water reabsorption Carbonic anhydrase inhibitors: much weaker; inhibit water reabsorption in the proximal tubule that normally occurs when bicarbonate is reabsorbed Osmotic diuretics: reduce reabsorption of water by adding extra solutes to the filtrate Potassium-sparing diuretics: block reabsorption of Na+ and secretion of K+ in the collecting duct
What are bile salts derived from? What is their function
Made from bile acids that are conjugated to glycine or taurine They are responsible for fat emulsification
Secretion of gonadotropins in males is regulated by
Maintained by Negative feedback effects of testosterone and inhibin
Menopause - What happens - Age - Explanation of effects - Symptoms
Menstruation stops usually occurs after age 50. Ovaries stop secreting estrogen. Not because of low LH and FSH, rather ovaries just grow insensitive to it. FSH and LH levels are actually elevated Symptoms: -Hot flashes -vaginal glands no longer produce lubrication. -risk for atherosclerosis increases (estrogen helps control cholesterol) - Risk of osteoporosis increases (estrogen inhibits osteoclasts)
Digestive Tract Motility - Def - Includes (5)
Movement of food through the tract Ingestion Mastication Deglutition: Swallowing Peristalsis Segmentation: Churning and mixing while moving forward
primary spermatocyte
One of the two daughter cells
Lower esophageal sphincter
Opens to allow food to pass into stomach and prevent backflow of stomach acid
Serosa of GI tract -function
Outer binding and protective layer
Extrinsic regulation of the GI Tract - Describe the different mechanisms
Parasympathetic: Nerves stimulate motility and secretions of the GI Tract Sympathetic: Nerves reduce peristalsis (inhibit rest and digest)
secondary spermatocytes.
Produced after meiosis 1. Creates 2 haploid cells
Zona pellucida
Protective protein layer that forms around oocyte to protect it from more sperm
Function of microflora in large intestine What does it help maintain?
Regulate final absorption and excretion Disruption can lead to Inflammatory bowel disease Maintains: - Healthy epithelial barrier - limits inflammation - Promotes repair of damaged epithelium
Function of the liver 2
Regulates the chemical composition of the blood produces/secretes bile used for digestion
gonadotropin-releasing hormone (GnRH) - Released from - Function
Released by hypothalamus controls the release of FSH and LH
Chief cells
Secrete pepsinogen, a zymogen of pepsin
inhibin - Secreted by - Function
Secreted by the the Sertoli cells of the seminiferous tubules or the granular cells surrounding the oocyte It inhibits secretion of FSH.
Spermiogenesis and Sertoli Cells
Sertoli cells create a blood-testis barrier to prevent the immune system from attacking sperm secrete FAS ligand, which binds to the FAS receptor on T cells and kills them so they can't attack sperm secrete androgen-binding protein (ABP) into the seminiferous tubule. Concentrates testosterone which stimulates spermatogenesis and spermiogenesis
Which is the major barrier in the glomerulus for the filtration of plasma proteins? What happens if it's defective?
Slit diaphragm pores are the major barrier for the filtration of plasma proteins A defect in the slit diaphragm causes proteinuria = proteins in urine
Muscularis of GI Tract
Smooth muscle Does segmentation and peristalsis
Enterohepatic circulation
Some molecules released into bile are reabsorbed in the small intestine and returned to the liver
spermatogonia
Spermatogenic stem cells in the testes
Locations of absorption in the small intestine
Sugars, lipids, amino acids, calcium, and iron are absorbed in the duodenum and jejunum Bile salts, vitamin B12, water, and electrolytes are absorbed in the ileum
Deglutition - Def - Parts
Swallowing Parts: - Oral: Voluntary. Bolus is formed - Pharyngeal: Involuntary. Uvula covers nasopharanyx and epiglottis covers larynx - Esophageal: Automatic. Controlled by the swallowing center of the brain stem
In males, LH Secretion is controlled by
Testosterone via a negative feedback loop. High testosterone turns off LH. Low Test turns on LH
Loop of Henle permeability
The descending limb is permeable to water but not to ions like sodium and chloride. The ascending limb is impermeable to water but actively transports ions, particularly sodium and chloride, out of the tubule into the surrounding interstitium.
How does the liver detoxify the blood? 3
The liver can remove hormones, drugs, and other substances in 3 ways: 1. Excretion into bile 2. Phagocytosis by Kupffer cells 3. Chemical alteration by hepatocytes
Ovarian Luteal Phase
The luteal phase is the second half of the ovarian cycle (days 14-28). After ovulation, LH stimulates the ruptured follicle to become a corpus luteum. The corpus luteum secretes estradiol and progesterone. High levels of estradiol and progesterone exert a negative feedback on FSH and LH secretion.
renal plasma threshold - Def
The minimum blood concentration of a substance that results in the excretion of that substance in the urine. Like too much sugar = sugar in urine
Obligatory water loss - Def - How much is it?
The minimum volume of urine per day that needs to be excreted to rid the body of wastes. 400 ml
macula densa - Def - Function
The part of the distal tubule that contacts the granular cells of the afferent arteriole for help regulating GFR When there's excess Na+ and H2O a signal is sent to inhibit renin. Renin inhibition means more salt is excreted and less is absorbed.
corpus luteum
The remaining follicle after ovulation Secretes estradiol and progesterone Becomes a nonfunctional corpus albicans at the end of a nonfertile menstrual cycle
Endocrine Functions of the Testes
The two compartments of the testes interact with each other in a paracrine fashion. -The tubules secrete paracrine regulators that may influence Leydig cell function. -Testosterone from the Leydig cells is required for spermatogenesis.
Leydig cells - What do they release - Whats the effect
Their testosterone production stimulates the development of the Wolffian ducts to develop into rest of the male reproductive organs (epididymis, ductus deferens, seminal vesicles, and ejaculatory duct).
primary oocytes. - Contained where? - How many at birth?
They are contained within primary follicles There are 2 million primary oocytes in a newborn
Fatty acids in the Large intestine - Function - Produced from what (repeated)
They are produced from undigested polysaccharides And once they are produced they can be used for energy by large intestine epithelia Fatty acids can also help stimulate absorption of electrolytes like sodium and chloride and water
How do diuretics work
They trick the kidneys into excreting more sodium and water than usual This helps decrease blood volume and pressure
LDL cholesterol - What is it - What does it do
Transport cholesterol to organs ("Bad")
HDL cholesterol - What is it - What does it do
Transports cholesterol away from organs to liver ("Good") HDL particles bind to receptors in the blood and capture phospholipids and free cholesterol, which reduces blood cholesterol. Once the surface area on the HDL is taken up, it travels to the liver and unloads the cholesterol.
Musculature of the esophagus
Upper esophagus lined with skeletal muscle innervated by somatic motor neurons Lower esophagus lined with smooth muscle controlled by ANS
Hepatic portal vein includes what veins? Where does blood go when leaving the liver?
Veins from the pancreas, gallbladder, stomach, omentum, and spleen all join with the hepatic portal vein Blood leaves the liver via the hepatic vein and rejoins the regular venous circulation
Villi and microvilli - What is their function - What are they part of
Vili are further folds in the plicae circularis and microvilli are further folds of the villi. All of which are mechanisms to increase surface area and absorption
Urea
Waste product of protein metabolism that also contributes to hypertonicity of interstitial fluid in the medulla
What can the large intestine absorb
Water, electrolytes, vitamin K, and some B vitamins
Ovulation Phase of Ovarian cycle
When one follicle becomes a mature Graafian follicle, it forms a bulge on the surface of the ovary. LH surge stimulates graafian follicle to rupture at day 14, and it releases the secondary oocyte
acrosome
a cap of digestive enzymes, forms during spermiogenesis
The glomerulus is
a capillary network that filters blood solutes into urinary system.
Mullerian ducts - Who has them - What do they become
become female accessory organs.
Small intestine parts (3)
duodenum, jejunum, ileum
Plicae circulares
folds of the mucosa and submucosa in the small intestine wall
Whats a nephron
functional unit of the kidney responsible for the formation of urine.
Inulin - Use
great marker of glomerular filtration rate because it is filtered but not reabsorbed or secreted. Creatine is used more commonly
Intrinsic factor
helps small intestine absorb vitamin B12
In males, FSH secretion is limited by
high levels testosterone (somewhat) but mostly by high inhibin levels.
Gherlin
hormone produced by your stomach that stimulates hunger and decreases satiety
amenorrhea - Def - Possible cause
lack of menstruation Can be caused by low body fat
Digestive Tract Functions (6)
motility secretion digestion: Breaking down food absorption: passing broken down food to blood or lymph storage/elimination immune barrier
Gi tract layers 4
mucosa, submucosa, muscularis, serosa
Gastric pits - Def - Lined with - Contain (6)
openings to folds in the gastric mucosa Lined with gastric glands that contain secretory cells: - Mucus neck cells: secrete mucus - Parietal cells: secrete HCl and intrinsic factor - Chief cells - Enterochromaffin cells (ECL) - G cells - D cells
What is bile made of 5
phospholipids, inorganic ions, bilirubin, cholesterol, bile salts
Things that affect testosterone
physical inactivity, obesity, and drugs
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) - Where producted - Functions
produced in the anterior pituitary glands of both males and females -Stimulation of spermatogenesis or oogenesis. -Stimulation of gonadal hormone secretion. -Maintenance of the structures of the gonads.
Kidney Function
regulation of the extracellular fluid in the body
Enterochromaffin-like (ECL) cells
secrete histamine and serotonin
SRY Gene - What is it
sex determining region of the Y chromosome
testis-determining factor (TDF) - Def/Function
signal that promotes embryonic gonads conversion to testes
seminiferous tubules - What are they - When do they form
site of sperm production Form after the production of the testes determining factor
D cells secrete
somatostatin
Vasa Recta - What are they - Function
specialized blood vessels around loop of Henle They help create the countercurrent system by maintaining high salt concentrations. Salt and other solutes diffuse into the descending vasa recta, and then passively diffuse out of the ascending vasa recta.
Where is bilirubin produced
spleen, liver, and bone marrow
Pulsatile secretion - Def -Function -Examples
the episodic secretion of hormones in periodic bursts or spurts to prevent desensitization GnRH, Lh, and FSH
Describe the role of the renin-angiotensin-aldosterone system in the regulation of plasma Na+ concentrations
the renin-angiotensin-aldosterone system is activated in response to factors such as low blood pressure or sodium levels. It leads to the production of angiotensin II, Angiotensin II helps narrows blood vessels, to increase blood pressure. It also stimulates the release of aldosterone. Aldosterone promotes the reabsorption of sodium. Water follows sodium. This helps increase blood volume, maintain plasma sodium concentrations, and regulate blood pressure
Cryptorchidism - Def
undescended testes. Infertile
Glomerular filtration rate (GFR): - Def - How much filtrate per day - How often is total blood volume filtered
volume of filtrate produced by kidneys -180 L/day (~45 gal) -Total blood volume is filtered every 40 minutes
Tonicity of the collecting duct and surrounding medulla - Effect
•The fluid entering the collecting duct is hypotonic (low solute so water wants to leave) the fluid in the surrounding medulla is hypertonic (high solute so water wants to go towards it) Water osmoses into intersitital where it enters capillaries (This rate is what ADH modifies)
Countercurrent multiplication - Def
•the positive feedback mechanism which multiplies the concentration of interstitial fluid and descending limb fluid.
