Physiol Exam 4: Chps. 17-18, & 20 Flashcards
Name the 2 organs that remove drugs from the blood
Kidney and liver
Identify the structures that form the nephron vs. renal corpuscle vs. renal tubule
Nephron:
- Renal corpuscle
- Renal tubule
Renal corpuscle:
- Glomerulus
- Glomerular capsule
Renal tubule:
- PCT
- (ascending & descending limb of the) nephron loop
- DCT
- CD
Describe the following terms: filtration, reabsorption, secretion
- Filtration: Process where components of blood (water and dissolved solutes) are removed and enter the nephron (glomerular capsule) → becomes filtrate
- Reabsorption: molecules from filtrate going back to the blood
- Secretion: fluids from the blood goes to the filtrate
Name the blood vessel that sends blood to the glomerulus vs. takes it away
Afferent arteriole - sends blood to the glomerulus
Efferent arteriole - takes blood away from the glomerulus
Name the 2 capillaries that efferent arterioles can send blood to (and percentage) & name the type of nephron each capillary is associated with
(85%) Cortical nephron = Peritubular capillaries
(15%) Juxtamedullary nephron = Vasa recta
Describe the location of the podocytes relative to the glomerulus
Makes contact with the glomerulus
Memorize the substances normally filtered vs. not filtered at the renal corpuscle
Normally filtered:
- Na+
- K+
- Cl-
- H+
- NH4+
- HCO3-
- H2O
- Glucose
- AA
- Urea
- BUT small amounts of albumin is filtered
Not filtered:
- Proteins mostly excluded (large size and net negative charges)
Name the 3 barriers/filters that permit filtration at the glomerulus
- Capillary fenestrae: contains charges; repels proteins from getting across
- Basement membrane: restricts rate of fluid flow the most
- blocks larger proteins - Filtration slits: spaces between foot processes of podocyte; covered by slit diaphragm
Describe how filtrate is formed
Formed by blood hydrostatic pressure
- 20% of blood gets filtered
- Remaining 80% of blood leaves
Memorize the value & unit for net filtration pressure
Net filtration pressure (pressure from both sides of the BV) ~10 mmHg
Define GFR
Glomerular filtration rate (GFR) = Volume of filtrate formed by both kidneys each minute
Name the 3 methods used to control GFR
- Sympathetic control
- Renal autoregulation
- Hormonal control (RAA system)
Describe the sympathetic control of GFR
Sympathetic control of GFR; Negative feedback
1. Stimuli - ↓BP (→ Baroreceptor reflex) OR Exercise
2. = ↑ Sympathetic nerve activity
3. Effects:
a. ↑ Cardiac output (↑HR, ↑contractility)
b. Vasoconstriction of afferent arterioles in kidneys → ↑TPR
OR
→↓GFR →↓ Urine production → ↑ Blood volume and blood pressure
c. Vasoconstriction in skin and GI tract →↑TPR
Name the substances reabsorbed at the PCT
- Na
- K
- Cl-
- H+
- NH4+
- HCO3-
- H2O
- glucose
- AA
- albumin
Memorize the percentage of filtered glucose & amino acids normally reabsorbed at the PCT & describe how it is reabsorbed
Glucose & AA’s filtered (at glomerulus) but 100% reabsorbed @ PCT
* Reabsorbed through secondary active transport (cotransport) with Na+ (Na+ diffuse in along w/ sneaking in glucose)
Memorize the percentage of the filtrate salt & water normally reabsorbed at the PCT
~65% filtrate Na+, Cl- & H2O reabsorbed (at PCT) & returns to blood
Describe the purpose of the countercurrent multiplier & name the part of the nephron where it occurs
Purpose: concentrate ECF (surrounding the nephron), to assist in reabsorbing water by CD (so less water ends up in urine)
- Occurs at nephron loop (renal medulla) of the renal tubule
Name the particles that ascending limb of the nephron loop is permeable vs. impermeable to
*Opposite to what occurs in the descending limb
Permeable to:
- NaCl (active transport/ATP; from lumen into interstitial fluid)
- MAYBE K+ (via secondary active transport - symport); Na+ -K+ -2 Cl cotransporter
NOT permeable to:
- H2O
Name the particles that descending limb of the nephron loop is permeable vs. Impermeable to
*Opposite to what occurs in the ascending limb
Permeable to:
- H2O
Impermeable to:
- Passive diffusion (high→low; no ATP) of salt
Name the 3 ions & 1 molecule that contribute the concentrated ECF surrounding the nephron
Ions:
- Na+
- K+
- Cl-
Molecules:
- Urea
Describe the purposes of the countercurrent exchange & name the blood vessel where it occurs
- Purposes:
1. Maintains hypertonicity of renal medulla by trapping solutes (NaCl & urea)
2. Remove H2O from interstitial fluid; prevent dilution of renal medulla - Occurs at vasa recta
Name the hormone that targets the collecting duct & describe the hormone’s effect at the collecting duct when there is an increase vs. decrease in that hormone’s levels
ADH/vasopressin
1. ↑ ADH
- → kidneys (specifically the CD)
- ↑ Water reabsoprtion (by osmosis; high to low [H2O])
- → Less water excreted in urine = more H2O return to blood to dilute that high plasma osmolality
- ↓ ADH
- → kidneys (specifically the CD)
- ↓ Water reabsoprtion
- → More water excreted in urine = water is being removed from blood
Name the structure that synthesizes vs. secretes ADH/vasopressin
Synthesized by - hypothalamus
Secreted by - posterior pituitary
Describe how ADH leads to aquaporins being inserted into the cell membrane
- ADH leaves the blood and binds to the ADH receptor on the cell membrane (polar)
- Once it binds to receptor → cAMP (2nd messenger system) goes into cytoplasm and bind to vesicles containing aquaporins (water channels) → will then insert it into the apical surface (faces lumen of CD/filtrate)
- More H2O can move via osmosis (high to low [H2O]) from CD lumen → CD cell → (medullary) interstitial fluid → blood = Blood reabsorbs H2O, so less ends up in urine
Name the 2 substances used to estimate GFR, describe the source(s) of each substance
- Inulin (fructose polymer from plants; like garlic and onion)
- Creatinine (from skeletal m.)
Name the substance used to estimate renal blood flow
Para-aminohippuric acid (PAH)
Memorize the details of the negative feedback loop involving the RAA system
Drop in BP (stimulus) is sensed by the granular cells of kidneys (sensor), causing it to secrete renin and converting angiotensin, from the liver, to angiotensin I. At the lungs, Angiotensin-converting enzyme (ACE) converts angiotensin I to Angiotensin II, causing many things…
1. Target cells of the hypothalamus to stimulate thirst → drinking
2. Target cells of the cardiovascular system causing vasoconstriction
3. Target the adrenal cortex to stimulate secretion of aldosterone → sodium and water retention/reabsorption of kidneys
— This all ultimately leads to elevated levels of BP
Distinguish hyponatremia vs. hypernatremia. Distinguish its normal range.
Hyponatremia: abnormally low plasma Na+
Hypernatremia: abnormally high plasma Na+
Normal blood Na+: 135-145 mEq/L
Name the 2 parts of the nephron targeted by aldosterone
- DCT
- Mainly CD
Distinguish hypokalemia vs. hyperkalemia. Distinguish its normal range
Hypokalemia: abnormally low plasma K+
Hyperkalemia: abnormally high plasma K+
Normal blood K+: 3.5-5 mEq/L
Name the 2 locations of the nephron where K+ is secreted
- DCT
- CD
Name the hormone involved in K+ secretion
Aldosterone: @ apical membrane - Na+ reabsorption leads to K+ secretion (into filtrate)
Name the 2 particles that Na+ can be exchanged for when Na+ is reabsorbed at the DCT & CD and distinguish when would these particles be secreted
H+ and K+
* Plasma H+ indirectly affects plasma K+ @ DCT or CD, K+ or H+ secreted when Na+ reabsorbed
— Depends on the blood level:
~ Alkalosis or hyperkalemia means more K+ will be secreted
~ Acidosis means more H+ will be secreted
* Also, H+/K+ pump on apical membrane pumps H+ into filtrate in exchange for K+ (out of filtrate)
Describe the purpose of diuretics
Goal: ↑ urine volume excreted; ULTIMATELY get rid of excess fluid and Na+ from blood
(OPTIONAL) What are the 4 types of diuretics? Describe them.
- Carbonic anhydrase inhibitors: Weak diuretic; inhibits carbonic anhydrase (production of H2O and CO2 from H+ and HCO3-), interfering with H2O reabsorption = H2O stay in filtrate → urine
- Loop diuretics: Most powerful; @ ascending limb of nephron loop interfering with NaK2Cl- transporter and keep these ions + water within filtrate = ↑ urine volume
- Thiazide diuretics: interferes with NaCl reabsorption at DCT = stay in filtrate and so will H2O
- Potassium-sparing diuretics: targeting/blocking reabsorption of Na+ and secretion of K+ (Aldosterone) → stays in filtrate as well as H2O = ↑ urine volume
Define motility
Motility: Movement of food
Distinguish deglutition vs. mastication vs. peristalsis vs. segmentation
Deglutition: Swallowing
Mastication: Chewing; mixing food w/ saliva = blous
Peristalsis: “move”; moving bolus down esophogus by contracting and stretching
Segmentation: “mix”; chyme (food + stomach acid and gastric juices) will go back and forth within the small intestine, mixing with its enzyme on the cell membrane, “brush border enzymes”
Memorize the 4 layers of the GI tract & how the layers are arranged (from superficial to deep & vice-versa)
Deep → Superficial
1. Mucosa
2. Submucosa
3. Muscularis externa
4. Serosa
Name the layer of the GI tract that contains the submucosal plexus vs. myenteric plexus
Submucosal plexus: nerve supply to muscularis mucosae and gland secretion
— Found within submucosa layer of GI tract
Myenteric plexus: found between muscle layers; controls their contraction
— Found within muscularis externa
Distinguish the effect the parasympathetic vs. sympathetic innervation has on motility & secretion
- Parasympathetic (“rest and digest”): stimulates motility & secretions
* Preganglionic parasympathetic fibers synapse on submucosa and myenteric plexuses - Sympathetic (“fight or flight”): inhibit parasympathetic’s functions and stimulate sphincter contraction (so it won’t continue the process of motility)
Identify the type of muscle tissue found in each 1/3 of the esophagus & describe the type of control each muscle would be under (voluntary vs. involuntary)
- Upper 1/3: Skeletal m. = Voluntary
- Middle 1/3: Skeletal - Smooth m. mix
- Lower 1/3: Smooth m. = Involuntary → Peristalsis (movement from one end of a tube to another) into stomach
Memorize the function of the following gastric gland cells: parietal cell, chief cell, G cell, ECL cell
Parietal cell: secretes HCl and intrinsic factor (for absorption of vitamin B12)
Chief cells: Secrete pepsinogen and gastric lipase (digest lipids)
G cell: Secrete gastrin
Enterochromaffin-like (ECL) cells: Secrete Histamine
Memorize the details of how HCl is secreted into the stomach lumen
- Parietal cells are responsible for secreting HCl
1. Within parietal cell, CO2 and H2O (+ carbonic anhydrase) forms H2CO3 (carbonic acid) → dissociates into H+ and HCO3-
2. HCO3- goes to the blood capillaries, serving as a buffer, and gets exchanged for Cl-, entering parietal cell
3. H+ goes to stomach lumen and gets exchanged for K+, entering parietal cell
— via primary active transport w/ ATP
— K+ may leak out since [high] inside vs [low] outside
4. Cl- also goes to stomach lumen via facilitated diffusion - HCl makes gastric juice very acidic, pH < 2
Name the precursor of pepsin
Pepsinogen (secreted by chief cells)
Describe the 3 ways the stomach protects itself from HCl & pepsin
- Adherent layer of mucus containing HCO3- (helps neutralize the H+ from HCl-)
* Stuck on epithelial cells surface = “barrier” - Tight junctions = preventing substances from going between the cells
- Rapid mitosis; of epithelial cells (3 days)
Name the substances absorbed by the entire small intestine (Combine the duodenum, jejunum & ileum as the small intestine)
- Carbs/carbohydrates
- Amino acids
- Lipids
- Ca2+
- Fe2+
- Bile salts
- Vitamin B12 (if intrinsic factor present)
- Electrolytes
Describe the function of intrinsic factor
Intrinsic factor: for intestinal absorption of vitamin B12
Distinguish the function of the capillaries vs. lacteal at the small intestine
At the small intestine
Capillaries: absorption of carbohydrates and amino acids
Lacteals: absorption of lipids and fat-soluble vitamins (A,D,E,K)
Describe the brush border
Microvilli (extension of enterocytes/columnar epithelium of villi) AKA Brush Border
* Contain brush border enzymes
Describe the location & function of brush border enzymes
Located at: Cell membrane of microvilli/ brush border of SI
Function: hydrolyze substrates
Describe the function of the brush border enzyme enterokinase
Enterokinase: activates trypsin by activating it’s precursor, trypsinogen at the pancreas
Name the 2 duodenal hormones
Secretin and Cholecystokinin (CCK)
Secretin: Name the stimulus for its secretion, name the target cells & their secretions, & describe the function of the secretions
- Stimulated by duodenal pH < 4.5
Target cells:
1. Cells of pancreatic duct - secrete H2O and HCO3-
— helps neutralize the acidic H+ that are in the chyme
2. Bile duct cells of liver - secrete H2O and HCO3- INTO bile
— the bile will enter the duodenum and mix with chyme = neutralize H+ and increase pH
CCK: Name the stimuli for its secretion & name the target structures & their secretions
- Stimulated by fat and protein content of chyme
Target cells:
1. Pancreatic acini - secrete/release pancreatic juice enzymes
— needed to fully digest what we consume
2. Gallbladder - contracts, releasing/secreting bile, IF fat is present
Distinguish the 2 major types of motility in the small intestine
- Peristalsis: rhythmic wave-like contractions ; pushing of one end to another end
- Slow and weaker than in esophagus & stomach = give enough time for contents of chyme to digest and absorb in SI - Segmentation: mixing contractions in different segments ; to make chyme more exposed to brush border enzymes
- Major SI contractile activity
Name the substances absorbed by the entire large intestine
- H2O
- Electrolytes
- Vitamin K and B vitamins
Name the 3 substances produced by the microflora (gut bacteria-probiotics w/n large intestine)
- Vitamin K
- (Variety) B vitamins
- Short-chain fatty acids
Describe the function of Kupffer cells
Detoxifies blood (remove hormones, drugs & other biologically active molecules from body) via phagocytosis
Name the organ that synthesizes bile
Liver (hepatocytes)
Name the 3 macromolecules that the liver is responsible for the metabolism of
- Carbs
- Proteins
- Lipids
Name the organ that stores & concentrates bile
Gallbladder
Name the cells in the pancreas that synthesize digestive enzymes vs. bicarbonate in pancreatic juice
Pancreatic acini - synthesize digestive enzymes; targeted by CCK
Pancreatic duct - synthesize bicarbonate ; targeted by secretin
Describe the general contents of pancreatic juice, name the location in the pancreas that pancreatic juice gets secreted into & name the region of the small intestine that the pancreatic juice eventually gets secreted into
Contents of pancreatic juice:
- Water
- Sodium bicarbonate
- ~ 20 different digestive enzymes and zymogens (inactive enzymes; will become activated at the duodenum w/ brush border enzymes)
* Secreted into pancreatic duct → duodenum
Describe the function of trypsin & name its zymogen that is found in pancreatic juice
Trypsin - can activate other zymogen/pancreatic juice enzymes once activated by trypsinogen (activated by enterokinase)
* Enterokinase → trypsinogen (zymogen) → trypsin → other zymogens/pancreatic juice enzymes
Name the organ that synthesizes & secretes many of the enzymes (ex.trypsinogen, etc.) involved in the digestion of carbohydrates, protein & lipids
Pancreas
Sugars & starches: name the locations where they are digested in the body & name the enzymes involved in their digestion in the small intestine
Digestion for starch occurs at:
1. Mouth - uses salivary amylase as enzyme
EX: Starch → maltose
2. SI (duodenum) - uses pancreatic juice enzymes and brush border enzyme
Describe the source & function of salivary amylase
Source: Saliva
Function: Enzyme for starch, converting it to maltose
Proteins: name the locations where they are digested in the body & name the enzymes involved in that location
Digestion for protein occurs at:
1. Stomach - uses pepsin
2. SI (duodenum and jejunum) - uses pancreatic juice enzyme and brush border enzyme
Lipids: name the locations where they are digested in the body, name the enzymes involved in their digestion in each location
Digestion for lipids occurs at:
1. Mouth - uses lingual lipase
2. Stomach - gastric lipase
3. SI (duodenum) - pancreatic lipase (with colipase)
Describe the function of pancreatic lipase (with colipase)
Function: Only occurs AFTER emulsification; convert triglycerides/emulsification droplets into fatty acids and monoglycerides
- Colipase aids by coating the emulsification droplets and “anchors” the lipase enzyme to them
Describe emulsification with bile
Occurs FIRST, then digestion
1. Fat globule causes the release of cholecystokinin (CCK) → Causes the release of bile to the SI
2. Bile converts fat globule into emulsification droplets
— NOT DIGESTION; emulsify SEPERATES fatty globules into smaller fatty droplets
Describe how free fatty acids & monoglycerides enter the enterocytes, name the particle they form after entering & name the structure that particle gets exocytosed into
- Free fatty acids and monoglycerides come together to transport in H2O (micelles) and pass through the brush border of SI and enter into the enterocyte
- Then breaks apart from the micelles back to fatty acids and monoglycerides inside the enterocyte
- Fatty acids and monglycerides get rebuilt into chylomircon to get exocytosed into lacteals → veins in neck
Distinguish the purpose of VLDLs vs. LDLs vs. HDLs
VLDLs: Produced by liver (consists of cholesterol and triglycerides), deliver and store the leftover triglycerides at adipocytes
LDLs: Made from VLDLs, containing mainly cholesterol; cells absorbs LDLs by receptor mediated endocytosis
HDLs: Empty HDLs shells produced by liver → HDLs shells pick up cholesterol and phospholipids from tissues → Filled HDLs return to liver → Liver excretes excess cholesterol and bile acids (Remove and degrade cholesterol)
Name the hormone that increases at the onset of puberty
Luteinizing hormone
Name the testicular cell that responds to FSH vs. LH
Sustentocytes (of seminiferous tubules) - affected by FSH
Interstitial cells (of interstitial tissues) - affected by LH
Describe the function of the interstitial cell
Function: secrete testosterone
Memorize the hypothalamus-pituitary-testes axis
Hypothalamus - Pituitary - Testes Axis
Hypothalamus
↓ GnRH
Anterior Pituitary
↓FSH AND LH
Testes
1. FSH → Seminiferous tubules → Inhibin
- Negative feedback: some inhibin goes to ant. pit. to stop secretion of ONLY FSH
2. LH → Interstitial cells → Testosterone → target cells
- Negative feedback: some testosterone goes to hypothalamus to stop secreting GnRH
- Negative feedback: some goes to anterior pituitary to stop responding to GnRH
Name the initial precursor molecule used to synthesize testosterone
Cholesterol
Summarize the purpose of spermatogenesis
Spermatogenesis: Production of sperm cells through stages of cell division
Name the cells formed during each step of spermatogenesis
Spermatogonia (2N) → undergoes mitosis
- Primary spermatocytes (2N) → undergoes meiosis I to produce…
- 2 Secondary spermatocytes (N) → undergoes meiosis II at the start of puberty to produce…
- 4 Spermatids (N) → undergoes spermiogenisis to produce…
- 4 Spermatozoa (N)
Describe spermiogenesis & the changes that are happening to the gamete at the sustentocyte
Spermiogenisis: Spermatids become spermatozoa; at sustentocyte in semineferous tubule
- Phagocytosis of spermatid cytoplasm…
- Result: Spermatozoon consists of head (with nucleus) + acrosome (cap of digestive enzymes) + flagellum tail
List the 4 functions of sustentocytes & describe the purpose of each function
- Form blood-testis barrier
- Forces substances that needed to enter or leave will have to go through the sustentocyte
- Sets testis up as an immunologically privileged site; immune cells can’t have access to this region so it won’t go after the spermatazoa due to DNA not being recognizable from meiosis - Produce FSA ligand, binds to to T- lymphocyte’s FAS receptors = apoptosis
- Secrete ihibin: inhibit secretion of FSH
- Spermatogenesis
Identify the autonomic nervous division responsible for the following: erection, emission, ejaculation
— Erection: (Parasympathetic)
* Vasodilate (due to NO to blood vessel smooth m.)
* ↑ blood flow to corpora cavernosa; P compress veins (so blood doesn’t leave right away)
— Emission: (Sympathetic)
* Movement of semen INTO urethra
— Ejaculation: (Sympathetic)
* Forcible expulsion of semen from urethra OUT the penis
Name the initial precursor molecule used to synthesize progesterone & estrogen
Cholesterol
Summarize the purpose of oogenesis
Oogenisis: Production of an ovum
Name the cells formed during each step of oogenesis
Oogonium (2N) → undergoes mitosis
- Primary oocyte (2N) →undergoes meiosis I; stops at Prophase I until puberty
- First polar body (N) AND Secondary oocyte (N) →undergoes meiosis II; stops at metaphase II (due to LH increasing during puberty = LH reduces inhibition caused by granulosa cells) until fertilization and ovulation
- Second polar body (N) AND Ovum (N)
Name the specific stage in meiosis (phase & number) the primary oocyte is arrested at birth
Primary oocyte at birth/towards end of gestation (pregnancy)
- ARRESTED AT: Prophase I (of meiosis I)
Name the specific stage in meiosis (phase & number) the secondary oocyte is arrested at when ovulation occurs
Secondary oocyte when ovulation occurs/starting from puberty
- ARRESTED AT: Metaphase II (of meiosis II)
Name the events necessary to convert the secondary oocyte into the ovum
Ovulation (Day 14 of ovarian cycle) AND fertilization
Summarize the purpose of folliculogenesis
Folliculogenesis: Development of the follicle
Name the follicles formed during each step of folliculogenesis
- Primordial follicle
- Primary follicle
- Secondary follicle
- Mature follicle
Describe the follicular cells found in each follicle of folliculogenesis
- Primordial follicle - With ogonia (stem cell), then primary oocyte
- Primary follicle - Primary oocyte
- Secondary follicle - Primary oocyte
- Mature follicle - Secondary oocyte
Identify the features associated with each follicle of folliculogenesis
- Primordial follicle
- Flat follicle cells (surrounding oogonia or primary oocyte) - Primary follicle
- Follicle cells become cuboidal
- FSH causes it to grow
- Goes from 1 to several layers of cells/stratified (called granulosa cells) - Secondary follicle
- Lots of vesicles (fluid-filled cavity) develop - Mature follicle
- Contains zona pellucida, corona radiata, cumulus oophorus, and antrum (vesicles fused together)
Name the hormone synthesized by the cells of theca interna & describe how it relates to the granulosa cells
Theca cells produces: Testosterone (due to LH)
— Testosterone is received by the granulosa cells and will convert it to estrogen via aromatase
— FSH also increases the amount of aromatase in granulosa cells = more estrogen
Identify the hormone synthesized by the granulosa cells
Estrogen
Identify the 3 hormones secreted by the corpus luteum
- Progesterone
- Estradiol
- Inhibin
Match the ovarian cycle phases with the uterine cycle phases based on the days of the menstrual cycle
- Follicular phase (ovarian cycle) ↔ 1. Menstrual cycle and 2. Proliferative cycle (uterine cycle)
- Ovulation on Day 14: Ovaries release secondary oocyte and uterus receives it if ovulation occurs - Luteal phase (ovarian cycle) ↔ 3. Secretory phase (uterine cycle)
Follicular phase (Days 1-13):
i. Describe the effect FSH has on the ovarian follicles
ii. Memorize the positive feedback loop that occurs during this phase
FSH ↑ at beginning of phase
i. FSH causes:
- Some primary follicles grow→ secondary follicles (1 secondary follicle will become mature follicle)
- Granulosa cells make increasing amounts of estradiol
ii. Rapid rise of this hormone (estradiol) acts on hypothalamus
- → ↑ frequency of GnRH pulses/secretion + augments(increase) pituitary’s response ↑LH secretion (LH surge) = positive feedback due to estradiol
Ovulation:
i. Describe the event that happens during ovulation
ii. Identify the hormone responsible for ovulation
i. As high levels of FSH causes the development of follicles, estrogen levels also rise, further increasing FSH and LH
- LH is responsible for the ovulation of the secondary oocyte (w/ zona pellucida and corona radiata)
ii. LH
Luteal phase:
i. Describe the effect LH has on the empty ovarian follicle
ii. Memorize the negative feedback loop that occurs during this phase
iii. Identify the hormone that increases the most after ovulation
↑ of LH at this point
i. LH causes empty follicle to become corpus luteum
- Secretes progesterone, estrogen, and inhibin
ii. Neg. feedback on pituitary (LH and FSH fall) ; Progesterone and estrogen targets hypothalamus causing negative feedback = LH and FSH levels drop and progesterone and estrogen levels rise
iii. After ovulation, progesterone appears and ↑ most
Summarize the main events that occur during each of the phases of the uterine cycle
- Menstrual Phase (Days 1-4); menstruation occurs
— Old endometrium shedded - Proliferative Phase (Days 5-14); new endometrium enters and ovulation
— Estradiol (from granulosa cells) stimulates proliferation/growth of functional layer (endometrium)
— Development of spiral a. - Secretory Phase (Days 15-28)
— Progesterone & estradiol (from corpus luteum)→ Uterine glands develop + thicker, vascular & spongy endometrium (uterus is ready for implantation)
Identify the organ where fertilization normally occurs
Uterine tubes
Define the following: cleavage, implantation
Cleavage: mitosis (of zygote) in 1st 3 days after fertilization
Implantation: trophoblast cells of blastocyst attaches and penetrates into the endometrium on the 6th day following fertilization
Identify the organ where implantation normally occurs
Endometrium of uterus
Identify the function of trophoblast cells
Trophoblast cells make enzymes to burrow into endometrium and secrete human chorionic gonadotropin (hCG)
- Will become the placenta
Identify the function of hCG
Secreted by trophoblasts
- Function: Identical to effects of LH
Describe the purpose of the corpus luteum during early pregnancy
Early pregnancy, corpus luteum needed to release estrogen & progesterone, preventing menstruation (maintaining endometrium)
- Corpus luteum is around until the placenta is formed
Describe the purpose of the placenta
Allows substances to be exchanged between mom and fetus
Describe the roles that the placenta & fetus have on the production of progesterone & estrogen
Mom has to rely on placenta and fetus to make progesterone and estrogen due to corpus luteum being gone
1. (Maternal blood) Cholesterol → (Placenta) Cholesterol convert to Progesterone → Progesterone back to mom
2. … Progesterone also goes to fetus and converts to androgen → (Placenta) androgen convert to estrogen → estrogen goes back to mom
Define parturition
Parturition: process of giving birth
Identify the 2 substances that cause uterine contractions
Oxytocin and prostaglandin
Identify the type of feedback parturition entails
Positive feedback
Describe the function of PIH
Inhibits the release of prolactin/milk-production
Memorize the reflex involved in milk production
Suckling (stimulus) → sensory input → hypothalamus → anterior pituitary → prolactin → milk production (response)
Memorize the milk-ejection reflex
Suckling (stimulus) → sensory input → hypothalamus → posterior pituitary → oxytocin → milk ejection (response)
