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PNB 2265 Exam #4

Terms in this set (265)

What does the LH surge do?
1. Ovulation of secondary oocyte
2. Causes first meiosis division to happen (primary oocyte to secondary ooctye)
3. Formation of corpus luteu
What do extra cells from the follicle after ovulation go?
Corpus luteum
What does the corpus luteum release?
Estrogen and progesterone
What kind of feedback does estrogen have at high levels?
Positive feedback
How many days does the corpus luteum stay in a nonpregnant individual?
10 days
What day does ovulation occur in a 28 day cycle?
Day 14
What follicle goes through all the way to ovulation?
Vesicular follicle
What are the primary reproductive organs in male and female?
Ovaries (female) and testes (male)
What are the functions of the primary reproductive organs?
Gametogenesis and secretion of sex steroids
What are the accessory reproductive organs?
Ducts systems and glands opening into ducts
What is a primordial gonad?
Gonad in developing fetus that has the ability to develop into either an ovary or teste
What part of the gonad develops into an ovary or teste depending on what it supposed to happen for that fetus?
Medulla of gonad can develop into testis
Cortex of gonad can develop into ovary
What is the function of seminiferous tubules, where are they located, and what two cell types do they have?
Located within the testes and work to develop sperm
Two types of cells (1) Sertoli cells: support cells and (2) Dividing germ cells that produce sperm
What are interstitial leydig cells, what is their function and where are they located?
Located outside the seminferous tubules within the testis in the interstitial space. They make androgens (testosterone)
Function of the testes
Produce sperm and male hormones (testosterone)
What happens as cells migrate towards the lumen of seminiferous tubules?
Mature into spermatozoa (not quite fully mature)
Where do sperm finish maturing?
Epididymis
Function of epidymis
Give sperm final motility to finish maturing
Function of vas deferens
Transports sperm from epididymis to ejaculatory duct
What are the two erectile muscles on penis and what is their structure?
Corpora cavernosum and corporus spongiosum

Network of venous spaces surrounded by central artery
What are the accessory glands?
Seminal vesicles
Prostate
Bulbourethral

Make semen
What do seminal vesicles do?
Produce alkaline viscous fluid that contains nutrients such as fructose to nourish sperm and prostaglandins
What does the prostate gland do?
Secretes fluid with enzymes that are used to activate sperm. Contains fibrinolysin and acid phosphatase.

Acid phophatase is unique to prostate and levels can be tested during prostate cancer treatment
What does the bulbourethral gland do?
Secretes a clear mucous that is used to lubricate during ejaculation and neutralize any acidic urine left in the urethra (pre)
Where are ovarian follicles?
Contained in the ovaries ONLY
What is ovulated?
Secondary oocyte (NOT mature ovum!!!)
Explain the flow of sperm through the male reproductive tract
Seminiferous tubules
Rete Testis
Efferent ductules
Epididymis
Vas deference
Ejaculatory duct
Urethra
Are the ovaries connected to the fallopian tubes?
NO! At the ends of the fallopian tubes are fimbriae which have cilia that move to create currents to pull ovulated secondary oocyte into the tubule. So the flow of an oocyte is ovary, abdominal cavity and then fallopian tube
Where are ovarian follicles located?
Ovaries
What is a follicle in general?
Oocyte surrounded by cells
Primordial follicle
Oocyte surrounded by a single layer of falt squamous like granulosa cells
Primary follicle
Oocyte surrounded by TWO layers of cells which have begun to differentiate and the zona pellucida (membrane)
1) cuboidal granulosa cells
2) thecal cells
Secondary follicle
Oocyte surrounded by multiple layers of granulosa cells
Antrum
Enlarging fluid filled space in a follicle that characterizes the tertiary stage
Tertiary Follicle
Antrum appears and grows
Graffian (mature) follicle
Large antrum, oocyte surrounded by stalk of granulosa cells
What happens on days 1-14 of typical 28 day cycle?
Multiple pre- and early antral follicles develop and one oocyte is ovulated on day 14
What happens on day 14 of a 28 day cycle?
One secondary oocyte ovulates
What are the three layers of the uterine wall?
1) Perimetrium
2) Myometrium
3) Endometrium
What is the perimetrium?
Outermost serous layer of the uterine wall
What is the myometrium?
Middle thick layer of smooth muscle in the uterine wall
What is the endometrium?
Inner mucosal layer of the uterine wall consisting of two layers
1) Stratum basalis
2) Stratum functionalis
What is the stratum basalis?
Outer layer of the endometrium that is referred to as the regenerative layer. Does NOT shed with the mentrual flow and cells from the stratum basalis proliferative each month to replensih the functional layer
What is the stratum functionalis?
Outer layer of the endometrium that is referred to as the functional layer. This layer responds to overian hormones and Is shed each month with the mentral flow. Cells in the functional layer are replenished with cells from stratum basalis
Explain the flow of vascular supply in the uterus
Uterine arteries
Arcuate arteries
Radial branches
Straight arteries (supply stratum basalis)
Spiral arteries (degenerate with the menstral flow each month and regenerate with stratum functionalis)
What do the straight arteries supply?
Stratum basalis
What do the spiral arteries supply?
Stratum functionalis. These arteries are unique because they degenerate and regenerate each month with the menstrual cycle
What arteries degenerate and regenerate each menstrual cycle?
Spiral arteries
What happens in general during the ovarian cycle?
Development of ovarian follicle
What happens in general during the epithelial cycle?
Changes in the epithelial lining of the uterus
What does GnRH do and where is it located?
Located in the hypothalamus and signals for the secretion of anterior gonadotropins (FSH and LH)
What signals for the release of FSH?
GnRH
What signals for the release of LH?
GnRH
What does FSH do and where is it located?
Follicle stimulating hormone, stimulates gametogenesis in both males and females. Located in the anterior pituitary and is released by GnRH
What does Lh do and where is it located?
Leutinizing hormone stimulates the formation of corpus luteum after ovulation
When does oogenesis begin?
Begins before birth, baby girl is born with all the primary oocytes they will have for life. Oogenesis is arrested before the first meiosis division until that oocyte is ovulated as a secondary oocyte
What undergos the primary meiosis division each month?
One primary oocyte goes through meiosis 1 to become a secondary oocyte which is ovulated
When does the second meiosis division occur for oogenesis?
Only when a secondary oocyte is fertilized
What happens on day one of the ovarian cycle?
First day of mentrual bleeding
What happens on days 1-7 of the ovarian cycle?
Days 1-5 bleeding
Days 1-7 several follicles develop
What happens on days 7-14 of the ovarian cycle?
Increase in LH and one follicle becomes dominant and tertiary and proceeds to be ovulated
What happens on day 14 of the ovarian cycle?
Ovulation
What happens on days 14-28 of the ovarian cycle
The luteal phase in which the corpus luteum functions to secrete estrogen and progesteron to build up the stratum functionalis and then it degenerates
What happens on days 1-14 of the ovarian cycle?
Follicular phase in which bleeding occurs, follicular development, and the domination of one follicle
What happens on days 14-25 of the ovarian cycle?
Corpus luteum functions and secretes estrogen and progesteron
What happens on days 25-28 of the ovarian cycle?
Corpus luteum degenerates in the OVARY!! (it never goes to the uterus)
What prompts the primary oocyte to complete the first meiotic division?
LH
What does the corpus luteum develop from?
Left behind granulosa cells from the secondary oocyte
What kind of oocyte do primary follicles have?
Primary oocyte
What kind of oocyte do secondary follicles have?
Primary oocyte
What is estrogen?
Anabolic steroid hormone
What cell produces estrogen?
Granulosa cells
How is estrogen produced?
Granulosa and thecal cells together produce estrogen during the follicular phase and by the corpus luteum during the luteal phase.

Thecal cells produce androgens which seep into nearby granulosa cells. Granulosa cells contain an enzyme that converts androgens to estrogen
What signals thecal cells to produce androgens?
LH
What signals granulosa cells to convert androgens to estrogen?
FSH
What does progesterone do?
Known as the pre-pregnancy hormone because it transforms endometrium into something that can support pregnancy
Where is progesterone produced?
SOME is produced in granulosa cells but MOST is made by the corpus luteum
What is the dominant steroid during the luteal phase?
Progesterone
Why do estrogen levels rise during the follicular phase?
Developing follicles have granulosa and thecal cells so they are able to produce estrogen
What happens to estrogen levels after dominant follicle has been established?
Rapidly rise, occurs on day 7
What happens after the estrogen rise on day 7?
LH surge
What does the LH surge cuase?
Ovulation of the secondary oocyte and formation of corpus luteum
What are hormone levels during the luteal phase?
Corpus luteum pumps out a lot of progesterone (dominant hormone during this time) and some estrogen. Combination of estrogen and progesterone shuts off LH and FSH
Why do estrogen and progesterone levels fall at the end of the luteal phase?
Corpus luteum degenerates
What do estrogen and progesterone inhibit?
LH and FSH. So when estrogen and progesterone levels are low on day one of the cycle, LH and FSH can be higher
What are the target cells for FSH?
Granulosa cells of ovary
What is the target cell for LH?
Thecal cells of the ovary
What does estrogen feedback mostly inhibit?
LH
What does inhibin do?
Produced by the granulosa cells it inhibits FSH
What inihibits LH?
Estrogen
What inhibits FSH?
Inhibin
What kind of feedback does low levels of estrogen cause?
Negative feedback on LH
What kind of feedback does high levels of estrogen cause and why is it significant?
Positive feedback on GnRH and LH to cause the LH surge
What are the three results of the LH surge?
(1) completion of meiosis 1 to produce secondary oocyte (2) rupture of ovarian follicle for ovulation (3) conversion of left behind cells of ovarian follicle into corpus luteum to produce estrogen and progesterone for 10 days
What kind of feedback do high levels of progesterone and estrogen have?
Negative feedback to inhibit GnRH and LH (in this stage, inhibin from follicles inhibit FSH)
What do the menstrual phase and proliferial phase of the uterine cycle match up with in the ovarian cycle?
Follicular phase
What are the phases of the uterine (endometrial) cycle?
1) Menstrual phase: shedding of stratum functionalis
2) Proliferal phase: stratum functionalis is rebuilt under the influence of estrogen
3) Secretory: progesterone causes uterine wall to thicken and convert to secretoary to be capable of supporting an embryo
What phase of the ovarian cycle corresponds with the secretory phase of the uterine cycle?
Luteal phase
What are the 4 functions of granulosa cells?
1) Nourish oocyte
2) Chemical messangers influene oocyte and thecal cells
3) Produce estrogen
4) Product inhibin
What hormone proliferates endometrium
Estrogen
What hormone allows endometrium to become secretory?
Progesterone
What does SRY do?
Allows for the conversion of the medulla of primordial gonad to develop into testes
Waht does SOX9 do?
Converts SRY to testes
What does SF1 do?
Keeps SRY on to continue with testes
What do serotoli cells do in gender differentiation?
Product AMH which causes the regression of mullerian ducts
What do Leydig cells do?
Product testosterone
What does testosterone do in gender differentiation?
Activates Wolffian ducts and DHT (in the presence of %-alpha-reductase)
What do Wolffian ducts do?
Create male duct system including epididymis, vas deferens, and seminal vesicles
What does 5 alpha reductase do?
Convert testosterone to DHT which is required for urogenital sinus external male genitalia
What happens when there is a lack of SRY?
Cortex of primordial gonad develops into ovary
Waht does DAX1 do?
Help to shut off SOX9
What does WNP4 do?
Help to shut off SOX9
What does FOXL2 do?
Help to shut off SOX
What happens when DAX1, WNP4, and FOXL2 shut off SOX9
No AMH or testosterone is produced
What is AMHR2?
Anti Mullerian hormone receptor, allows mullerian ducts to form
What happens when mullerian ducts form?
Fallopian tubes, uterus, and upper vagina form
What is the female counterpart to the male prostate?
Urethra
What is the female counterpart of the male cowpers?
Posterior vagina
What is the female counterpart to the male glans penis?
Clitoris
What is the female counterpart to the male penis?
Labia minora
What is the female counterpart of the male scrotum?
Labia majora
What does the renal system do?
Filters blood and removes metabolic waste, specifically nitrogenous waste
5 Functions of the renal system?
1) Excrete metabolic end products (drugs, organic molecules, xenobiotics)
2) Regulate ion balances (Na+, K+, Ca2+, HCO3-)
3) Regulate osmolarity and pH
4) Endocrine organ
5) Long-term regulation of blood pressure
What does the kidney do?
Filtration, absorption and secreton
What does the ureter do?
Transports urine from the kidney to the bladder
What does the urinary bladder do?
Temporarily stores urine before excretion
What does the urethra do?
Excretes urine to the external environment
What is the cortex of the kidney?
Outer area, and inner juxtamedullary region
What is the medulla or the kidney
Inner area, renal pyramids
What are the calyces of teh kidney?
Minor: papillae extend
Major: converge to form renal pelvis
What is a nephron?
Functional unit of the kidney
What are the two types of nephrons?
1) Juxtamedullary: Loop of Henle dips deep into the medualla. Important for creating osmotic gradient of concentrated urine
2) Cortical: Loop of Henle is short and most of the nephron is in the cortex of the kidney. Used for most renal processes
What is filtration?
Non-selective process of filtering solutes, water, and small molecules out of the blood and into the nephron
Location: Bowman's Capsule
Where does filtration occur?
Bowman's capsule
What is reabsorbtion?
Selective movement of water and solutes from the lumen of the nephron into the blood vessels (peritubular capillaries)
-use of transporters
Peritubular capillaries
Blood vessels around the nephron
- vasa recta in a juxtamedullary nephron
Vasa Recta
Peritubular capillaries around a juxtamedullary nephron
Where does reabsorption take place?
(1) Proximal convoluted tubule, (2) loop of henle, (3) distal convoluted tubule, and (4) collecting duct
What arteriole bring blood to the nephron?
Afferent arteriole
What arteriole brings blood away from nephron?
Efferent arteriole
What arteriole (afferent or efferent) has a larger radius at rest?
Afferent
What is secretion?
Use of active transporters to bring water and solutes into nephron from excretion
Where does secretion take place?
(1) Proximal convoluted tubule, (2) distal convoluted tubule, and (3) collecting duct
Whaat is beneficial about having a filtration system?
Large filtration system allows for speed in removing harmful things from the blood. Then we can selectively put things back that we still need
Fenestrated capillaries
Few tight junctions so things can filter through. Can be found on the glomerules for paracellular transport
Podocytes
Cells that warap around glomerulus to create pores and filtration slits that allow for the filtration of water, solutes, and small molecules but NOT RBC, WBC, and proteins
What governs bulk flow?
Pressure! Specifically hydrostatic pressure
What makes up the filtration barrier in the glomerulus?
Fenestrated epithelium, basement membrane (negatively charged to repel proteins), and podocytes
Explain size exlusion in filtration?
Podocytes create filtration slits that exclude large cells such as RBC and proteins
What are the filtration forces?
1) Hydrostatic pressure inside glomerulus (GBHP) pro-filtration force
2) Hydrostatic pressure inside capsule (CHP) anti-filtration force
3) Colloid Osmotic FOrce (BCOP) anti-filtration force
What is GBHP?
Force from the glomerulus pushing things through into the nephron. Driving force for filtration.
It is important that this force is greater than the combined CHP and BCOP for filtration to occur
- 55 mmHg
What is filtrate?
What comes out of the glomerular space into capsular space
Filtrate = Plasma - Protein - Cells
What influences GFR?
1) Arterial pressure
2) Afferent arteriole resistance
3) Efferent arteriole resistance
How does the afferent arteriole affect GFR?
Dilating afferent arteriole increases GFR
Constricting afferent arteriole decreases GFR
How does the efferent arteriole affect GFR?
Dilating efferent arteriole decreases GFR (less pressure)
Constricting efferent arteriole increases GFR (raises pressure)
What is the juxtaglomerular apparatus (JGA)?
Collection of mascula dense and granular cells where the DCT meets the afferent arteriole to help regulate GFR
Flow Autoregulation
Maintains constant GFR even with fluctuations in blood pressure so that filtration doesn't change a lot due to environmental factors
Macula Densa Cells
In the JGA and contain osmoreceptors that detect a change in osmolarity in the distal convoluted tubule and then make adjustments to the GFR accordingly
Granular cells
In the JGA and release renin
Mesangial Cells
Smooth muscle that can contract or dilate the radius of the afferent arteriole in response to stretching as a result of changing blood pressure
3 ways GFR is regulated
1) Myogenic Response: mesangial cells respond to stretching of vessels as a result of changing blood pressure
2) Tubuloglomerular Feedback: communucation between distal convoluted tubule and afferent arteriole based on osmolarity (Macula Densa Cells)
3) Hormone and Autonomic Neurons: RAAS, changes in arteriole resistance, renin
Explain the negative feedback loop in tubuloglomerular feedback
GFR increases and macula densa osmoreceptors recognize the increase osmolarity. Paracrine from macula dense to afferent arteriole to cause the arteriole to contract to increase resistance. This causes the hydrostatic pressure in the glomerulus to decrease to decrease GFR
What does adenosine from the macula densa do?
Vasoconstriction
What does nitric oxide from the macula densa do?
Vasodilation
What do alpha-adrenergic receptors do when activated?
Vasoconstriction
-short term blood pressure regulation
- decrease GHP and GFR
Explain RAAS
Renin converts angiotensinogen to angiotensin 1. The ACE converts aniotensin 1 to angiotensin 2 which increases blood pressure
What does angiotensin 2 do?
-vasoconstriction
-increase filtration
-ADH (vasopressin)
-acitvates aldosterone secretion

-causes vasoconstriction which increases peripheral resistance to increase BP
- also increases ADH released from posterior pituitary to increase H2O reabsorbtion to increase blood volume to increase blood pressure
- increases aldosterone release from adrenal cortex to increase sodium reabsorption in kidnets to increase H2O reabsorbtion to increase blood volume to increase blood pressure
-increases thirst to increase H2O intake to increase blood volume to increase blood pressure
Simply put, what does RAAS do?
Increase blood pressure
What stimulates granular cells to release renin?
Reduced blood flow
Sympathetic stimulation
Low tubular osmolarity
What do ACE inhibitors do?
Inhibit the conversion of angiotensin 1 to angiotensin 2 to block the affect for RAS
- used to lower blood pressure in patients with HIGH blood pressure
What cells release ANP?
Atrial cells in the myocardium
What are the effects of ANP?
-dilation fo afferent arteriole to inhibit renin
-constriction of effect arteriole
-inhibits Na+ reabsorption

decrease blood pressure, released in response to high blood pressure
What is renal clearance and why is it useful?
The volume of plasma from which something is completely removes over a period of time, and it is useful for estimating GFR
What are criteria for a substance to be used for renal clearance?
Needs to be a substance that is filtered through the glomerulus, but NOT absorbed or secreted
What are two substances discussed in the lecture that can be used for renal clearance?
Inulin: synthetic substance that is NOT produced by the body, but is filtered and not reabsorbed or secreted. Need to be injected

Creatine: produced by the body and is filtered, but not reabsorbed. It IS secreted though, so when calculating clearance you need to account for what has been secreted (about 10%)
How is renal blod flow (RBF) measured?
Using para aminohippurate (PAH) because it is freely filtered and anything that is not filtered is secreted. This is useful for measuring vasculature around kidneys (specifically peritubular capilliaries and vasa recta) because any PAH that goes through kidney is excreted
What is clearance PAH useful for measuring?
Renal flow
Explain how reabsorbtion and secretion are paired processes
Usually, when one molecule is reabsorbed, another is secreted
What is saturability?
When a carrier reaches it maximum rate of transport because all the binding sites are filled. This means that the excess solutes will be excreted in the urine
Renal Threshold
Plasma concentration of any solute that will cause solute to end up in urine
What solutes have a high renal threshold and why?
Glucose because it is important to save all the glucose possible for energy
-untreated diabetic patients will have high glucose concentrations in urine
What solutes have low renal threshold
Water and soluable vitamins (explains why vitamin supplements are not super effective)
Where does ADH come from?
Posterior pituitary
When is ADH released?
In response to low blood pressure to raise blood pressure
What transporters are on the apical and basolateral sides in the proximal tubule?
Apical: (1) AQP-1 to bring water into cell, (2) Na+/solute co-transporter to bring solute into cell, (3) OAT to exchange anions
Basolateral: (1) AQP-1 to reabsorb water and (2) Sodium potassium pump to maintain concentration gradient of Na+ for co-transporter to work
Function of proximal tubule?
Primary site of reabsorption and secretion
What does OAT do and where is it located?
Organic anion transporter located on the apical membrane of proximal tubule that allows for the exchange of anions such as bicarbonate and some drug
What is the difference between AQP-1 and AQP-2?
AQP-2 is hormonally regulated by ADH or vasopressin
Function of descending loop of henle
Permeable to water, extremely low permeability to most solutes, except it is permeable to urea
What transporters are located on the apical and basolateral membranes of the descending loop of henle?
Apical: (1) AQP-1 to bring water into cell and (2) UTA-2 to allow for secretion of urea
Basolateral: (2) AQP-1 to allow for reabsorption of water into peritubular capillaries
How does water move in the descending loop of henle?
Water moves through aquaporins on the apical and basolateral membranes according to a solute gradient
What is the function of the thin ascending limb in the loop of henle?
Impermeable to water and low solute permeability
What transporters are located on the apical and basolateral sides of the thin ascending limb?
Apical: AQP-1 NOT EXPRESSED
Basolateral: Leaky sodium pump
Function of thick ascending limb?
Impermeable to water, promotes ACTIVE transport of solutes
What transporters are expressed on the apical and basolateral sides of the thick ascending loop?
Apical: (1) NKCC2: to bring Na+, K+, and 2Cl- into cell, (2) ROMK to move potassium out of cell to maintain potassium homeostatis
Basolateral: (1) CLC: calcium activated chloride channel to allow for reabsorption of chloride. (2) Na/K ATPase to give sodium gradient for NKCC2 to bring sodium in and allow for reabsorption of sodium
What is NKCC2 and where is it located?
Pump on the apical side of the thick ascending limb that helps to being in Na+, K+ 2Cl- so Cl and Na+ can be reabsorbed
What is ROMK and where is it located?
Transporter located on the apical side of the thick ascending limb that moves K+ out of the cell to maintain K+ homeostasis
What is CLC and where is it located?
Calcium driven chloride channel located on the basolateral side of the thick ascending limb to allow for chloride reabsorption
What is the function of the sodium potassium pump in the thick ascending limb?
Allow for reabsorption of Na+ as well as drive active transport of solutes in thick ascending limb
What is the function of the distal tubule?
Solute reabsorption and water permeability which is hormonally regulated
What transporters are on the apical and basolateral side of the distal tubule?
Apical: (1) Na+ cotransporters (2) CFTR chloride channel for chloride reabsorption
Basolateral: (1) NCX: sodium calcium pump drive reabsorption of calcium (2) Sodium potassium pump (3) CFTR allows for chloride reabsorption
What does NCX do and where is it located?
Calcium sodium exchanger on the basolateral side of the distal tubule that allows for reabsorption of calcium
What is CFTR and where is it located?
Chloride channel located on apical and basolateral sides of distal tubule that allows for reabsorption of chloride
How is water permeability hormonally regulated and where?
Water permeability is hormonally regulated in the distal tubule and collecting duct and it is regulated by ADH or vasopressin (released from posterior pituitary) which releases vesicles contraining AQP-2 to move to apical membrane to allow for reabsorption of water
Function of collecting duct
Lower collecting duct is permeable to urea, which is regulated by ADH or vasopressin, and permeable to water (hormonally regulated)
How does urea reabsorption work in the lower collecting duct?
UTA-3 is a urea transporter that is ALWAYS present on the basolateral side. When vasopressin or ADH are released they bind to receptors on basolateral side which cause UTA-1 to be placed on the apical membrane to allow urea to be reabsorbed
How does water reabsorption work in the collecting duct?
It is hormonally regulated. When ADH or vasopressin binds to a receptor on the basolateral side it signals a signal cascade that releases vesicles containing AQP-2 to move to apical side to allow for reabsorption of water
How does ADH affect water reabsorption?
Drastically increases water reabsorption by allowing AQP-2 containing vesicles to move to apical membrane in distal tubule and collecting duct
What causes osmotic gradient in kidney?
Sodium chloride and urea
What is the concentration of urine during normal hydration?
Urine is isotonic to plasma
What is the concentration of urine during overhydration?
Urine is hypotonic to plasma (diuresis)
What is the concentration of urine during dehydration?
UJrine is hypertonic to plasma (antidiuresis)
How is osmoconcentration achieved?
Using vertical osmotic gradient in interstitial fluid of kidney
What happens to the concentration of urine in the loop of henle?
As filtrate moves down the descending limb and into the medulla, water is reabsorbed and the filtrate becomes more concentation. As the filtrate moves up the ascending limb, NaCl moves into the space between the descending and ascending limbs to dilute urine. The NaCl moving into the interstitual space pulls water from the descending limb

This process repeats to create a countercurrent multiplier
What is the Osm solute gradient capacity at each membrane segment from NaCl being reabsorbed?
200 mOsm
What is functional coupling?
Close proximity of descending and ascending limb allows for functional coupling when NaCl reabsorption from the ascending limb affects water reabsorption from the descending limb
Explain the countercurrent multiplier situation that occurs with urea
In the presence of ADH, urea is reabsorbed in the lower collecting duct by passive diffusion to further increase solute concentration at the loop of henle
What is the countercurrent exchange that occurs in nephrons and why is it important?
Filtrate in the nephron flows the opposite direction as the blood in the vasa recta. This countercurrent flow allows an osmotic gradient to be maintained
How is water and urea affected by the countercurrent exchange between the filtrate in the nephron and blood in the vasa recta?
Water reabsorbed in the descending limb or collecting duct is quickly taken away by the vasa recta. Urea reabsorbed in the collecting duct passes the descending limb where it is secreted back into the filtrate (recycled)
What is the relationship between osmoconcentration and loop of henle length
Multiplier is proportional to loop length (deeper loop of henle has stronger osmoconcentration)
What side is the chloride bicarbonate transporter on in Type A intercalated cells?
Basolateral
What side is the chloride bicarbonate transporter on in Type B intercalated cells?
Apical
What do Type A intercalated cells do?
Secrete H+ when you are in a state of acidosis (get rid of H+)
What do Type B intercalated cells do?
Absorb H+ when you are in a state of alkalosis (keep H+)
What do intercalated cells do and what are the types?
Cells that regulate pH in the distal convoluted tubule and collecting duct and there are two types (1) Type A and (2) Type B
Where are intercalated cells located?
Distal convoluted tubule and collecting duct
What muscle makes up the bladder?
Smooth muscle
Explain the process of urination?
Stretch receptors on the bladder signal parasympathetic neurons to contract which pushes open the interal sphincter to let you know you have to pee. The stretch receptors also inhibit the contraction of the external sphincter to allow it to relax
What is micturition?
Urination
What is ECF volume sensed by?
Baroreceptors in the vascular system
What happens in response to low blood pressure?
Increase concentration of solutes in the urine to increase plasma volume and increase blood presure
- use ADH
What happens in response to high blood pressure?
Dilute urine to decrease plasma volume to decrease blood pressure
What stimulates renin secretion?
Decreased blood pressure
What is ECF composition sensed by?
Chemoreceptors in the hypothalamus to control electrolyte homeostasis
What is released in response to increased K+?
Aldosterone because it increase the secretion of K+
What promotes salt and water excretion?
Natriuretic peptides
What regulates long term pH homeostasis?
Intercalated cells and bicarbonate reabsorbtion and excretion in PCT
How does the PCT regulate pH?
In response to acidosis it reabsorbs and produces bicarbonate to be reabsorbed. In response to alkalosis it excretes bicarbonate
What is the damming effect?
The AA is bigger than the EA to create a higher GBHP for better filtration
What is CHP?
Colloid hydrostatic pressure opposing filtration (15 mmHg)
What is BCOP?
Blood colloid osmotic pressure pulling water into capillaries (30 mmHg)
What is the NFP?
NFP = GBHP - CHP - BCOP
10 = 55 - 15 - 30
What does the macula densa do?
Senses osmolarity
How does the macula densa respond to >100 osmolarity in DCT?
Releases ATP to contrict ATP
How does macula densa respond to <100 osmolarity in DCT?
Releases NO to dilate ATP
Intrinsic autoregulation mechanisms?
(1) Myogenic: stretch from blood pressure causes contraction or dilation of AA
(2) Tubuloglomerulus Feedback: osmolarity sensed by the macula dense releases ATP or NO to either constrict or dilate AA
If fluid entering the distal tubule is too concentrated what is the response?
Macula densa senses high osmolarity and releases ATP to constrict AA to decrease GFR
If fluid entering the distal tubule is too dilute what is the response?
Macula densa sense low osmolarity and releases NO to dilate the AA to increase GFR
If renal blood pressure is high, what is the intrinsic response?
Stretch receptors constrict the AA to decrease GFR
If renal blood pressure is too low, what is the intrinsic response?
Stretch receptors dilate the AA to increase GFR
What is the osmolarity in the glomerulus?
300
What is the osmolarity in Bowman's Capsule?
300
What is the osmolarity in the Loop of Henle descending limb?
400-1200 (in medulla)
What is the osmolarity in the ascending limb of the loop of henle?
1200 in medulla and then goes does 200 at every NaCL absorbtion
What is the osmolarity in the distal tubule when no ADH is present?
100
What is the osmolarity of the most dilute urine you can make?
100
What is the osmolarity in the DCT when ADH is present?
300
What is the osmolarity as you move down the collecting duct when ADH is present?
400-1200
What is the osmolarity as you move down the collecting duct when ADH is not present?
100
What does furosemide do?
Lasix, blocks NCKK2 channel in ascending limp (loop diuretic) to lower blood pressure
What does thiazide do?
Blocks NCC in DCT to lower BP
What is the osmolarity in the cortex of the kidney?
300
What does aldosterone do?
Increases reabsorption of NA in the DCT to increase plasma volume in response to low plasma volume (low blood pressure) by creating more NCC channels
What does ADH do?
Increases H2O reabsorption in the late distal tubule adn collecting duct by adding aquaporin 2 channels to increase plasma volume in response to low blood pressure
What is Lisinopril?
ACE inhibitor (lowers BP) by preventing angiotensin 2 from forming and prevents AA constriction
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