urinary system Flashcards
what is the function of the kidneys
they excrete waste products, regulate blood volume pH and electrolytes, do hormone synthesis, and gluconeogenesis
what is the function of the ureters
they deliver urine to the urinary bladder
what is the function of the urinary bladder
it stores urine until excretion
what is the function of the urethra
is a duct that expels urine
what is the pathway of urine formation/drainage from the nephron to the urethra
collecting ducts, renal papillae, renal calyces, renal pelvis, ureter, urinary bladder, urethra
what is the structural and functional differences of the cortical and juxtamedullary nephrons
Structural:
cortical nephrons have short loops of henle while juxta have long loops of henle
Functional:
cortical nephrons can only concentrate urine with the same strength as blood (300) while juxta can create more concentrated urine (1200)
what is the role of the renal corpuscle (glomerulus) in the formation of urine
it creates the ultrafiltration of the blood
what is the role of the proximal tubule in the formation of urine
it uses cuboidal cells with microvilli to reabsorb water, glucose, and other solutes
what is the role of the descending loop of henle in the formation of urine
it reabsorbs water and creates the corticomedullary gradient
what is the role of the ascending loop of henle in the formation of urine
it undergoes the active transport of sodium and other ions using the corticomedullary gradient
what is the role of the distal tubule in the formation of urine
uses cuboidal cells to secrete and absorb water and ions
what is the role of the collecting duct in the formation of urine
receives fluids from distal tubules
what is the role of the vasa recta in the formation of urine
it is a capillary that maintains the corticomedullary gradient
which pressures promote glomerulus filtration and which oppose it
glomer hydrostatic pressure and bowman’s colloid osmotic pressure promote filtration while bowman’s hydrostatic pressure and plasma colloid osmotic pressure oppose it
how does increased or decreased glomerulus hydrostatic pressure effect filtration rate
increases or decreases will alter the overall net filtration pressure and GFR, it will increase when the GHP is increased and decrease when the GHP is decreased
what are the 3 mechanisms that regulate glomerular filtration rates (include stimuli, response, and impact on GFR)
renal auto reg:
myogenic is stimulated by high blood pressure, responds by contracting and constricting afferent arterioles, this decreases the GFR
Tubuloglo is stimulated by high blood pressure and high sodium/chlorine levels, responds by decreasing the levels of nitric oxide constricting afferent arterioles, this decreases the GFR
neural reg: this is stimulated by high levels of norepi and epi secretions, responds by constriction of systemic vessels and afferent arterioles, this decreased the GFR
hormonal reg:
angiotensin 2 is stimulated by low blood volume/pressure, responds by constricting afferent and efferent arterioles, this decreases the GFR
ANP is stimulated by high blood volume, responds by increased capillary surface area, this increases the GFR
what are the locations in the nephron that reabsorb each component of filtrate
The proximal tubule, loop of henle, distal tubule, and the collecting duct (principal and intercalated cells) are locations for reabsorption
what are the locations in the nephron that secrete hydrogen, potassium, bicarbonate, urea, creatinine, and ammonia
hydrogen: proximal tubule
potassium: distal tubule and collecting ducts
bicarbonate: collecting duct
urea: ascending limb of henle
creatinine: proximal tubule
ammonia: proximal tubule
what are the changes in fluid composition and osmolarity/tonicity throughout the nephron
the movement of water balances the osmotic within and across the tubules
which transport mechanisms (diffusion, osmosis, primary active transport) are used to move water, the major ions, and glucose across the cells of the proximal convoluted tubule.
water: diffuses through aquaporins through paracellular pathways
sodium: sodium potassium atpase pump (active transport)
major ions: diffuse through ion channels such as paracellular pathways
glucose: active transport
what is the difference between countercurrent multiplication and countercurrent exchange
counter current multiplication is where the interstitium is becoming more concentrated from the counter current flow it is building a gradient
while counter current exchange is where the vasa recta maintains the corticomedullary gradient
what is the difference between the functions of intercalated cells and principal cells in the late distal tubule
intercalated cells regulate blood ph and reabsorb potassium, bicarbonate, and secrete hydrogen
principal cells reabsorb sodium and secrete postassium
what is the mechanism to regulate water resorption by the hormone ADH and the cells that are involved.
when there is low blood volume/pressure ADH will be released and bind to receptors on principal cells to turn on g proteins which will result in aquaporins that will allow water to go where there is more concentrated urine to produce less concentrated urine
what is the stimuli, the hormones, and effects (of each hormone) in the renin-angiotensin-aldosterone system.
stimuli: blood pressure/volume decrease
hormones: renin and aldosterone are released
effects: glomerular filtration is decreased through vasoconstriction and reabsorbs sodium and water
what is the difference between the effects of the renin-angiotensin-aldosterone system and atrial natriuretic peptide on the reabsorption of H20.
ANP is different as it is triggered by high blood volume/pressure and inhibits the reabsorption of sodium and water
it is also a vasodilator while the other system is a vasoconstrictor
what are the normal physical and chemical characteristics of urine.
Physical: color, turbidity, odor, pH, specific gravity
Chemical: it is made up of 95% water and 5% solutes
urine will contain creatinine, uric acid, urea as wastes in the urine
what are the underlying physiological causes of various urine abnormalities.
volume varies based on fluid intake, diet, BP, and blood osmolarity
color varies on hydration state, infections, and renal damage
foaminess varies with protein diets and renal disease
smell can vary based on diet, hydration state, infections, and diseases.
high levels of white blood cells indicate urinary tract infection
high levels of glucose indicate diabetes
high levels of proteins indicate kidney disease
what are the functions of the detrusor muscle, internal urethral sphincter, and external urethral sphincter.
detrusor muscle is used to store urine and contract when urine needs to be released
both internal and external sphincters are used to prevent the release of urine when not needed
internal is for involuntary urine flow while external is for voluntary urine flow
what are the three major events that occur during the process of micturition, including the role of smooth muscle and skeletal muscle in this process.
- contraction of detrusor muscle (made of smooth)
- Opening of the internal urethral sphincter.
3.Opening of the external urethral sphincter. (made of skeletal)
role of smooth muscle: allows the bladder to stretch for filling and contract to release urine
role of skeletal muscle: they provide extra support to keep the urethra closed so urine doesn’t leak when urination isn’t happening
