Outcome 12 - Genitourinary System Flashcards
describe the location of the kidneys.
- retroperitoneal and around T12-L3
- right kidney typically lower than left
what are the 3 outer layers that surround the kidneys?
- renal fascia (anchors)
- perirenal fat capsule (protection)
- fibrous capsule (protection and shape)
what is the medial indentation on the kidney called? What can be found entering/exiting here?
renal hilum
- contains ureter, blood and lymph vessels and nerves
what is the outer region of the kidney?
renal cortex
what is the inner region of the kidney?
renal medulla
are the renal columns considered cortex or medulla?
cortex
what is each cone shaped region of the medulla called?
renal pyramid
where is the renal papilla found?
at the apex of each renal pyramid
where are the nephrons found?
within the renal parenchyma (cortex and medulla)
list the structures that urine flows through, after leaving the nephrons.
collecting duct –> papillary duct –> minor calyx –> renal pelvis –> ureter
what are some of the functions of the kidney?
- regulation of ions, pH, blood volume, BP, blood glucose
- maintain osmolarity
- hormone production
- excretes waste
How do the kidneys regulate pH?
by excretion of H+ and conserving HCO3-
how do kidneys regulate bp?
bp drops = secretion of renin
what are some hormones that the kidneys produce?
calcitriol and erythropoietin
what is gluconeogenesis?
use of amino acids to create glucose
what is osmolarity?
the number of dissolved particles (molecules, ions) per litre of solution
what is blood osmolarity?
~300 mOSm/L
each hilum expands into a cavity in the kidney and is called ____ ____.
renal sinus
describe the renal artery.
abdominal aorta –> renal artery
- renal artery is an end artery (if it’s block, there will be no flow in)
what view is the best to image the kidneys?
posterior view
people with horseshoe kidneys will need both _____ and _____ imaging.
posterior and anterior
what layer of the kidney connects it to the peritoneum?
renal fascia connects superficially
what does the renal lobe consists of?
a pyramid, region of cortex and 1/2 of the adjacent column
what is the renal parenchyma? what does it consist of?
the function portion of the kidney
- has the renal cortex and renal pyramids
why are kidneys very vascular?
- they get rid of wastes from blood
- control blood volume and bp
- control ionic composition of blood
what is the renal blood flow?
~1200 mL/min
what is the glomerulus?
a ball of capillaries that is sandwiched between two sets of arterioles
*unique to kidneys
afferent arteriole ______ (in/out) of kidney
efferent arteriole ______ (in/out) of kidney
afferent - in kidney
efferent - out kidney
what is the path of blow flow in the kidneys?
renal artery –> segmental arteries –> interlobar arteries –> arcuate arteries –> cortical radiate arteries –> afferent glomerular arterioles –> glomerular capillaries –> efferent glomerular arterioles –> peritubular capillaries –> per tubular venues –> cortical radiate veins –> arcuate veins –> interlobar veins –> renal vein
nephrons regenerate. t/f
they don’t.
we only have a set number of nephrons (1M/kidney)
what are the two major parts of the nephron? and what are their functions?
- renal corpuscle - filters plasma
- renal tubule - where the filtered fluid goes
what are the two parts that make up the renal corpuscle?
- glomerulus
- glomerular capsule (bowman’s capsule)
what’s the function of the glomerular capsule?
it filters plasma
what are podocytes?
simple modified squamous epithelial cells that make up the visceral layer of the capsule
what are the 3 parts of the renal tubule?
- proximal convoluted tubule
- nephron loop (loop of Henle)
- distal convoluted tubule
what type of nephron is found more superficially in the cortex and has a short loop of henle?
cortical nephrons
what type of nephron is found deeper into the cortex layer and has a long loop of henle?
juxtamedullary nephrons
what is the flow of fluid through a cortical nephron?
bowman’s capsule –> proximal convoluted tubule –> descending limb of the nephron loop –> ascending limb of the nephron loop –> distal convoluted tubule –> collecting duct
what is the flow of fluid through a juxtamedullary nephron?
bowman’s capsule –> proximal convoluted tubule –> descending limb of the nephron loop –> thin ascending limb of the nephron loop –> thick ascending limb of the nephron loop –> distal convoluted tubule –> collecting duct
what percentage of nephrons are cortical? juxtamedullary?
cortical - 80-85%
juxta - 15-20%
looking at the different cell types within the tubules, where does most of the reabsorption occur?
proximal convoluted tubule (65%)
which cells have receptors for aldosterone and ADH? where are they located?
principal cells found in the last part of the DCT and throughout the collecting duct
what are intercalated cells important for?
pH balance and secretion of calcium
what is macula densa?
a bundle of columnar tubule cells at the final part of the ascending limb + afferent arterioles
what are the walls of the afferent arteriole made of?
modified smooth muscle fibers - juxtaglomerular cells (renin)
what are the 3 steps to urine formation?
- glomerular filtration
- tubular reabsorption
- Tubular secretion
during glomerular filtration, where does water and solute go from and into?
BLOOD from glomerular capillaries through the filtration membrane and into the glomerular capsule
water and solute from:
BLOOD to GLOMERULAR CAPSULE (in the renal corpuscle)
what is the fluid called when it enters the capsular space?
glomerular filtrate
what happens during tubular reabsorption?
glomerular filtrate moves into the renal tubules where 99% of the filtered water and solute will go back into the blood
water and solute from:
renal tubules to blood by peritubular capillaries
what happens during tubular secretion?
transfer of waste, drugs and excess ions from blood into tubule cells + lumen of renal tubule
waste, drugs and excess ions from:
BLOOD to tubule cells + lumen of renal tubule
what are the two layers of filtration membrane?
- glomerular capillary vessel wall
- podocytes (visceral capsule)
what does the filtration membrane let pass? and what doesn’t go through?
pass - water and solutes
no pass - blood cells and plasma proteins
what are the three reasons filtration is much higher in the glomerulus?
- higher surface area in the glomerular capillaries
- thin and porous filtration membrane
- glomerular capillary blood pressure is high
what is the equation of the net filtration pressure (NFP)?
NFP = GBHP - CHP - BCOP
NFP = 10 mmHg
what is GBHP?
glomerular blood hydrostatic pressure
55 mmHg
what is CHP?
capsular hydrostatic pressure
15 mmHg
what is BCOP?
blood colloid osmotic pressure
30 mmHg
what is the glomerular filtration rate? what is the normal GFR in a male? female?
gfr = amount of filtrate formed in the renal corpuscles of both kidneys/minute
male - 125 mL/min
female - 105 mL/min
what are the two mechanisms that are used to regulate GFR?
- adjustment in blood flow in and out of glomerulus
- altering the glomerular capillary SA to compensate and maintain GFR
_____ (dilated/contracted) afferent arteriole + ______ (dilated/contracted) efferent arteriole = INCREASE GFR
dilated afferent + contracted efferent = increase GFR
_____ (dilated/contracted) afferent arteriole + ______ (dilated/contracted) efferent arteriole = DECREASED GFR
contracted afferent + dilated efferent = DECREASED GFR
________ (increase/decrease) capillary SA = INCREASE GFR
increase cap SA = increase GFR
________ (increase/decrease) capillary SA = DECREASE GFR
decrease cap SA = decrease GFR
what are three mechanisms to maintain constant GFR?
- autoregulation
- neural regulation
- endocrine regulation
what are the two mechanisms for autoregulation?
- myogenic mechanism
- tubuloglomerular feedback
what happens if the GFR is too high? too low?
too high = needed substances may not be reabsorbed
too low = waste products may not be excreted
what is myogenic mechanism?
vasoconstriction of afferent arterioles as a response to overstretching
what is tubuloglomerular feedback?
inhibiting nitric oxide (NO) release from juxtaglomerular apparatus which results in the vasoconstriction of afferent arterioles
blood vessels of the kidneys are influenced by _____ (ANS) fibers which releases ______.
What does this NT do?
sympathetic ANS fibers - releases NE
NE - causes vasoconstriction of afferent arterioles
which hormone reduces gfr?
angiotensin II
which hormone increases gfr?
atrial natriuretic peptide (ANP)
how does the hormone that reduces gfr work?
it causes vasoconstriction of both afferent and efferent arterioles = reducing blood flow
how does the hormone that increases gfr work?
stimulated by the stretching of the atria (increased blood volume) = secretion of ANP = relaxation of mesangial cells = increase capillary SA for filtration
where in the nephron do we find reabsorption and secretion happening?
collecting ducts
what is paracellular reabsorption?
when fluid leaks between cells in the proximal convoluted tubules in a passive process
- tight junctions in these epithelial cells of PCT are leaky
what is transcellular reabsorption?
when substances pass from the lumen from apical cell membrane
- movement across cytosol and then through the basal membrane and into interstitial fluid
*form of active transport (Na+/K+ ATPase pump)
what are 2 types of PASSIVE transportation that occurs during tubular reabsorption/secretion?
- simple diffusion
- facilitated diffusion
what are 2 types of ACTIVE transportation that occurs during tubular reabsorption/secretion?
primary and secondary active transport
what are 2 types of OSMOTIC transportation that occurs during tubular reabsorption/secretion?
- obligatory water reabsorption
- facultative water reabsorption
what is simple diffusion?
movement down concentration or electrochemical gradient
what is facilitated diffusion?
movement down the concentration or electrochemical with assistance from a carrier molecule (i.e. ion channel gate)
what is primary active transport?
use of energy produced by hydrolysis of A’‘\TP and transporters to pump substance across the membrane (Na+/K+ ATPase pump)
what is secondary active transport?
coupling the movement of ions and electrochemical gradients
what do you call membrane proteins that moves two or more ions in the SAME direction?
symporters
what do you call membrane proteins that moves substances in OPPOSITE directions?
antiporter
what is the difference between diffusion and osmosis?
osmosis is in relation to H2O
H2O following the concentration gradient
what is obligatory water reabsorption?
about 80% of H2O moving is following sodium, chloride and glucose
what is facultative water reabsorption?
about 20% of H2O is regulated by ADH (which means the adaptation based on need)
*in DCT and collecting duct
what does angiotension II do? what stimulates it?
it increases the reabsorption of Na+ and water
which increases blood volume and pressure
stimulated by low blood vol./pressure –> release of renin
what does aldosterone do? what stimulates it?
- increase secretion of K+ and reabsorption of Na+ and water = increase blood volume and pressure
stimulated by the increase of angiotensin II and plasma K+
what does ADH do? what stimulates it?
- increase reabsorption of water = increase blood volume + decrease blood osmotic pressure
stimulated by decrease in blood vol. or increase in blood osmotic pressure
what does ANP do? what stimulates it?
- inhibits reabsorption of Na+ and water
- suppresses secretion of aldosterone and ADH
= increases urine output and decrease blood vol./pressure
stimulated by the increase of blood volume due to stretching of atria
what does PTH do? what stimulates it?
- increases the reabsorption of Ca2+
- increase excretion of HPO42-
= increase Ca2+ and decrease HPO42- in plasma
stimulated by the decreased level of Ca+ in plasma
what is the anastomosis that occurs during kidney transplantation?
- between the internal iliac artery and external iliac vein
- ureter anastomosis or direct implantation into bladder
what substances are mostly reabsorbed?
water, proteins, Na+, Cl-, HCO3-, glucose (*zero in urine), K+
what is not reabsorbed?
creatinine + urea (some but not a lot)
what gives urine its color?
urochrome from the breakdown of bile and urobilin from breakdown of hemoglobin
what does BUN (blood urea nitrogen) test for?
- measures the blood nitrogen levels from waste product urea
which tests indicate a decrease in renal function?
too high BUN and/or too high creatinine
what does creatinine test for?
- measures the level of creatinine in the blood
– creatinine = product of creatine phosphate breakdown in skeletal muscles
what is renal plasma clearance?
the volume of blood that is cleared of a substance per unit of time (mL/min)
what does high renal plasma clearance indicate? low renal plasma clearance?
high = efficient excretion
low = inefficient excretion
what is the ideal substance used to test for renal plasma clearance? why?
inulin
- bc it is filtered by glomerulus but not reabsorbed or secreted
- clearance of inulin should = gfr
what is renal plasma flow?
- the amount of blood plasma that passes through the kidneys in one minute
how is renal plasma flow measured? what is the typical renal plasma flow?
substance used needs to be cleared from the blood in a single pass
typical - 650 mL/min, about 55% of renal blood flow
what are diuretics? how does it work?
- used to increase urine formation
- slows down reabsorption in tubules which causes diuresis (increased urine flow rate) + decreases blood volume
what diuretic inhibits Na+ reabsorption?
caffeine
what diuretic inhibits secretion of ADH?
alcohol
how does urine move in the ureters to bladder?
peristalsis of smooth muscle walls + hydrostatic pressure and gravity
what is the trigone?
the small triangular area in the inferior wall of the bladder
- consists of the two ureteral openings and the internal urethral orifice
the internal urethral sphincter is ______, while the external urethral sphincter is _______.
internal - involuntary
external - voluntary
what is the discharge of urine (urinating/voiding) called?
micturition
what is the last portion of the urinary tract?
urethra
what is the flow of urine formation?
afferent arteriole –> glomerular capillaries –> bowman’s capsule –> proximal convoluted tubule –> loop of henle (descending and ascending) –> distal convoluted tubule –> collecting duct –> papillary duct –> minor calyx –> major calyx –> renal pelvis –> ureter –> bladder –> urethra
how long does a typical female cycle range from?
24-36 days
what are the 4 phases of the female reproductive cycle?
- menstrual phase
- preovulatory phase
- ovulatory phase
- postovulatory phase
what is the menstrual phase?
about the first 5 days of the cycle
- shedding of the endometrium (inner most layer of uterus)
- in the ovaries, follicles are starting to develop which may take months to complete
what is the preovulatory phase? what is occurring?
time between end of menstruation and ovulation (about days 6-13)
- repair of the endometrium is occurring and it doubles in thickness
- in the ovaries, a single secondary follicle becomes dominant, tertiary follicle, and maturation is continuing
which part of the cycle makes up for most of the difference in women’s cycle lengths?
preovulatory phase
what is happening during the ovulation phase?
about day 14.
the secondary oocyte is released from the ruptured tertiary follicle and is swept into the fallopian (uterine) tubes
what is mittelscmerz?
the pain caused by the rupturing of the tertiary follicle during the ovulation phase
what is the post ovulatory phase?
between ovulation and next menstruation (about 14 days long or days 15-28 (during a 28 day cycle))
what is occurring in the ovaries during the post ovulatory phase?
- in the ovaries, the follicle collapses and is now the corpus luteum
- corpus luteum secretes hormones that stimulate the preparation of the endometrium for possible fertilized ovum (lasts for about 2 weeks if no fertilization occurs)
what is occurring in the fallopian tubes during the post ovulatory phase?
fertilization needs to occur within 24 hours of the oocyte release or the oocyte will continue towards uterus and disintegrate
at minimum, first 5 days = _______, next 5 days = _______
first 5 days = menstruation
next 5 days = preovulatory
when does the production of human chorionic gonadotropin (hCG) start?
about 8 days after fertilization from the embryo
what does the hCG do?
it stimulates the secretion of hormones from the corpus luteum which promotes the endometrial development
