Urinary System

what do kidneys regulate?

total water volume and solute concentration in blood, pH, blood pressure

what do kidneys remove?

metabolic wastes, toxins, drugs

what are the endocrine functions of the kidneys?

erythropoietin, renin

what is the importance of renin?

regulates blood pressure

what does erythropoietin function in?

regulation of red blood cell production

what do kidneys activate?

Vitamin D

what are the three external layers of connective tissue that each kidney is held in place and protected by?

renal facia, adipose, renal capsule

what is the outer region of the kidney?

renal cortex

what makes up the renal medulla?

renal pyramids, columns

what is the tip of the pyramid that releases urine into minor calyx?

papilla

what drains the renal pyramids at the papllae?

minor calyces

what collects urine from the minor calyces and empties the urine into the renal pelvis?

major calyces

what is the funnel-shaped tube continuous with the ureter?

renal pelvis

what conveys urine from the kidneys to the bladder?

ureters

what happens to ureters as bladder pressure increases?

distal ends close preventing backflow of urine

what mucosa is found in the ureters?

transitional epithelium

what is renal calculi?

kidney stones in the renal pelvis

what makes up kidney stones?

crystalized calcium, magnesium, or uric acid salts

what do kidney stones block and cause?

ureter, pressure and pain

what can cause kidney stones?

bacterial infection, urine retention, increased calcium in blood, increased pH of urine, diet

what is the treatment for kidney stones?

shock wave lithotripsy

what is the muscular sac for temporary storage of urine?

urinary bladder

what is the mucosa of the urinary bladder?

transitional epithelial mucosa

what is the muscularis of the urinary bladder?

detrusor

what do the openings for ureters and urethra form?

trigone

what tends to persist in the trigone region?

infections

what is the muscular tube draining urinary bladder?

urethra

what is the involuntary smooth muscle at bladder-urethra junction?

internal urethral sphincter

what is the voluntary (skeletal) muscle surrounding urethra as it passes through pelvic floor / urogenital diaphragm?

external urethral sphincter

what does the male urethra carry?

semen and urine

what are the three regions of the male urethra?

prostatic urethra, membranous urethra, spongy urethra

the spongey urethra opens via what?

external urethral orifice

what is the structural and functional units of the kidney that form urine?

nephron

what are the two parts of the nephron?

renal corpuscle, renal tubule

what is the tuft of fenestrated capillaries and is highly porous and allows for filtrate formation?

glomerulus

what is the cup-shaped hollow structure surrounding the glomerulus?

glomerular (bowman’s) capsule

what receives filtrate from many nephrons?

collecting ducts

what do the collecting dugs run through?

medullary pyramids

what gives the medullary pyramids a striated appearance?

collecting ducts

what cells of the collecting ducts maintain water and Na+ balance?

principal cells

what cells of the collecting ducts help maintain acid-base balance of blood?

intercalated cells

how are principal cells and intercalated cells regulated?

hormones

what are the classes of nephrons?

cortical nephrons, juxtamedullar nephrons

what are 85% of nephrons that are almost entirely in the cortex?

cortical nephrons

what are the nephrons that have a long nephron loop deeply inside the medulla?

juxtamedullary nephrons

what are juxtamedullary nephrons important in?

production of concentrated urine

what are the capillaries specialized for filtration?

glomerulus

why is blood pressure in the glomerulus high?

afferent arterioles larger in diameter than efferent arterioles

what do peritubular capillaries surround?

cortical nephrons and cortical structures of juxtamedullary nephrons

what is the additional structure that surrounds juxtamedullary nephrons?

vasa recta

what does the vasa recta surround?

loop of henle

where does the renal vein return blood to?

inferior vena cava

what are the 3 processes of urine formation?

glomerular filtration, tubular reabsorption, tubular secretion

what is tubular reabsorption?

movement from kidney to tubule back to blood

what is reabsorption important for?

reclaiming everything the body needs to keep

what is tubular secretion?

movement from the blood (peritubular capillaries) or cells lining the tubule into the tubule lumen

what forces fluids and solutes through the filtration membrane during glomerular filtration?

hydrostatic pressure

what makes glomerular capillaries unique?

they are supplied and drained by arterioles

is glomerular filtration a passive or active process?

passive, no metabolic energy required

what makes up the filtration membrane?

endothelium, basement membrane, podocytes

what makes up the endothelium of the filtration membrane?

fenestrated capillaries

what is between the foot processes of the podocytes?

filtration slits

what are the pressures that affect filtration?

hydrostatic pressure, pulling pressure

which pressure that affects filtration is known as the “pushing pressure?”

hydrostatic pressure

what pressure that affects filtration is known as the “pulling pressure?”

osmotic pressure

what makes up the net filtration pressure?

outward pressures - inward pressures

what is the net filtration pressure responsible for?

filtrate formation

what is the net filtration pressure the main controllable factor for?

determining glomerular filtration rate

what is the glomerular filtration rate directly proportional to?

net filtration pressure

what are the intrinsic controls of glomerular filtration responsible for?

renal autoregulation

what are the intrinsic controls to regulate glomerular filtration rate?

myogenic mechanism, tubuloglomerular feedback via juxtaglomerular complex

what are the hormonal extrinsic controls to regulate glomerular filtration rate?

renin angiotensin systen, ANP

what is the neural extrinsic control to regulate glomerular filtration rate?

sympathetic nervous system

what happens during the myogenic mechanism?

smooth muscle in afferent arteriole is stretched → wants to contract to counteract the stretch

what is the stimulus for myogenic mechanism?

increased blood pressure and glomerular filtration rate

what is the effect of the myogenic mechanism?

decreased glomerular filtration rate and blood pressure

what is located in the ascending limp of nephron loop and lies against the afferent arteriole?

juxtaglomerular complex

where are macula dense located?

distal convoluted tubule of juxtaglomerular complex

what are the chemoreceptors that sense concentration of Nacl in filtrate?

macula densa

what are the specialized smooth muscle cells in afferent arterioles that act as mechanoreceptors?

juxtaglomerular (granular) cells

what do juxtaglomerular (granular) cells respond to?

changes in blood pressure in afferent arteriole

what do juxtaglomerular (granular) cells release?

renin

what happens during the renin - angiotensin system?

renin is released from juxtaglomerular cells of afferent arteriole

what causes the release of renin in the renin-angiotensin system?

low blood pressure

what does the renin-angiotensin system stimulate the release of?

aldosterone from adrenal cortex, ADH from posterior pituitary

what is aldosterone release also stimulated by?

decrease in Na+ and increase in K+

what results from the vasoconstriction in efferent arterioles?

increase bp in glomerulus

what arterioles are constricted during the renin-angiotensin system?

efferent arterioles, systemic arterioles

what is the hormone released by heart cells in the atria in response to increasing fluid volume?

atrial natriuretic peptide (ANP)

how does the atria natiuretic peptide increase glomerular filtration rate?

dilating afferent arterioles and constricting efferent arterioles

what causes extrinsic neural controls?

systemic baroreceptors sense changes in blood pressure

what is the stimulus for extrinsic neural controls?

baroreceptors understreteched, low bp, low GFR

what is the effect of the extrinsic neural controls?

baroreceptors appropriately stretched, increase bp, increase GFR

where is angiotensin I converted into angiotensin ii?

lungs

if GFR decreases and kidneys are unable to carry out their vital functions what is it called?

renal failure

what is the condition that can develop when GFR is less than 50% of normal?

uremia

what can uremia lead to?

buildup of waste products, fluid, electrolytes, and acid base imbalances

what are the three classes of drugs that act on RAAS to reduce blood pressure?

ACE inhibitors, angiotensin-receptor blockers, aldosterone antagonistss

what is developed from snake venom, block ACE therefore inhibiting the conversion of angiotensin I to II?

ACE inhibitors

what blocks receptors on blood vessels and proximal tubule cells, prevents vasoconstriction and reabsorption of water and sodium?

angiotensin-receptor blockers