Urinary System Flashcards
what are the structures of the urinary system?
kidney
ureters
bladder
urethra
wht is the function of the kidney (renal pelvis)?
where urine is drained into
what is the function of ureters?
carry urine to urinary bladder
what is the function of bladder?
stores urine
what is the function of the urethra?
tube between bladder and external environment
what is the function of kidneys?
filtration (blood)
reabsorption
secretion
HOMEOSTASIS
what percentage of the bodys cardiac output is for the kidneys?
25%
whta is the functional unit of the kidney?
the nephron
how much plasma does the kidney process every day?
180L
what are the substances that are filtered and reabsorbed in the kidney?
water
sodium chloride
glucose
hydrogen ions
urea
toxic substances
what are the substances present in urine?
urea
ureic acid
creatinine
k+
toxic substances
what is the structure of the kidney (outside-in)?
renal cortex
renal medulla
renal pyramid
renal pelvis
ureter
what is the path of blood through the kidney?
renal artery
segmental artery
interlobar arteries
arcuate arteries
interlobular arteries
afferent arterioles
nephron
efferent arterioles
arcuate veins
interlobar veins
renal vein
what are the two functional units of the nephron?
vascular (blood)
tubular (filtered out)
what parts of the nephron are in the renal cortex?
bowmans capsule
proximal convoluted tubule
distal convulated tubule
what parts of the nephron are in the medulla?
loop of henle
collecting ducts
what are some characteristics about the renal cortex?
outer region of kidney
granular
what are some of the characteristucs of the renal medulla?
inner region of kidney
made up of triangles (renal pyramids)
what is the glomerulus?
a ball of capillaries
responsible for filtration
what is the bowmans capsule?
encloses glomerulus
in cortex
where filtration occurs
what is the proximal convulated tubule?
in cortex
responsible for most reabsorption and secretion
what is the loop of henle?
responsible for osotic gradient in medulla
what is the distal convoluted tubule?
in cortex
fine tuning of solute/water reabsorption
what is the collecting tubules/ducts?
in cortex/medulla
fine tuning of urine concentration
where are podocytes found?
in epithelium of bowmans capsule and surrounding capillaries
what are juxtaglomerular cells responsible for?
releasing hormones (renin) that control how much water is reabsorbed (fine tuning)
what are the characteristics of the barrier separating the blood and the interstitial fluid?
capillary wall
thin
vaiable barrier to h2o movement
little barrier to solute movement (except protein)
what are the characteristics of the barrier seperating the intracellular fluid and the extracellular fluid (plasma and interstitial fluid)?
cell membrae
very thin
little barrier to h2o movement
barrier to solute movement
what is the link between h2o and solutes in the body?
water is regulated through solute regulation
most important solute is Na+
(which is moved via a Na-pump, molecular mechanism, energy consuming, ‘up’ concentration gradient)
there is no equivalent molecular h2o pump
(h2o only ever moves via osmotic and hydrostatic forces, ie pumping of heart or osmotic effects)
what is the name of the ball of capillaries?
glomerulus
what is the name of the tubular structure that surrounds the glomerulus?
bowmans capsule
what is the name of the arteriole that takes blood to the glomerulus?
afferent arteriole
what is the name of the arteriole that takes blood away from the glomerulus?
efferent arteriole
what is hypertonic urine?
greater conc of solutes than another
what is hypotonic urine?
lower conc of solutes than another
what are the three implications of renal function?
need to maintain solute/ h2o balance in body
filtration into nephrons
reabsorption back into peritubular capillaries
what are the function that lead to excretion in the renal process (equation)?
excreted= filtered+secreted-reabsorbed
how is urine formed?
filtration
active transport
osmosis
where does filtration happen?
passive ultrafiltration at bowmans capsule
where does active transport happen?
energy driven retrival of valuble substances along nephron
where does osmosis happen?
mainly in loop PCT+ collecting duct
what is filtration in the renal process?
mass movement of water and solutes from plasma to the renal tubule
depends on glomerular capillary pressure
what is reabsorption in the renal process?
movement of water and solutes from the tubule back into the plasma
what is secretion in the renal process?
secretion of additional substances into the tubular fluid
what is contained within the renal corpuscle?
combination of glomerulus and bowman capsule
what are the filtration barriers in the renal corpuscle?
glomerular capillary basement membrane
basal lamina/membrane
bowmans capsule epithelia (podocytes)
what is hematuria?
red blood cells in urine
sign of damge to barrier
maybe from outside or inside kidney
what could damage the barrier of the outside of the kidney?
kidney stones
tumors
UTI
what could damage the barriers of the inside of the kidney?
inflammation og glomeruli
infarct-necrosis of kidney
what is proteinuria?
protein in urine
why is the protein, albumin, found in the urine of healthy people?
<7nm
can pass through the barriers
what is the process of reabsorption in the PCT?
- Reabsorption of most solutes is linked to the diffusion of Na +
- Carrier molecules for other molecules that co-transported
- Each of these carrier molecules binds specifically to that substances to be transported and to Na+
- Move with Na + into tubule cell
- As solutes are transported out of the lumen, through the proximal convoluted tubule cells, and into the interstitial fluid, water follows by osmosis.
- volume has been reduced by approximately 65%.
where are juxtamedullary nephrons in the kidney?
hypertonic medulla
what is the vasa recta?
counter current
long peritubular capillaries that dip into the medulla
blood flow in the vasa recta moves in the opposite direction from filtrate in the loops of henle
what are the characteristics of the loop of henle?
further reabsorption of NaCl and h2o by countercurrent multiplier
descending loop
asceding loop
what does the descending loop do?
permeable to water
filtrate becomes more concentrated as it loses water
what does the ascending loop do?
impermeable to water
actively transports Na+ into interstitial space followed by Cl
multiply the concentrations of Na+ eep in the medulla
what removes the water leaving the loop of henle?
blood in the vasa recta
what are the relations of the bladder in the male?
Anterior:
* pubic symphysis
Posterior:
* rectum
* ductus deferens
* seminal vesicles
Superior:
* peritoneum
* intestines
Inferior:
* prostate gland
what are the realtions of the bladder in the female?
Anterior:
* pubic symphysis
Posterior:
* vagina
Superior:
* uterus
Inferior & lateral:
* muscles of the pelvic floor & sidewall
what are the characteristics of the ureters?
- Tubes carry urine from
each kidney to bladder - 25–30 cm long & ~3-4 mm
in diameter - Pass urine by peristaltic
waves (smooth muscle) - Enter the back of bladder
- Urine backflow - prevented
by ureterovesical valves
what is the structure of the bladder?
hollow smooth muscle organ
bladder can be divided into two parts:
1) body (lying above ureteral orifices)
2) base (consisting of trigone and bladder neck)
what are the characteristics of the urinary baldder?
- The only involuntary organ in the body under voluntary control
- All humans are incontinent at birth
- Activation of numerous neurologic reflexes are learned in
early life to control the bladder - 35+ reflexes coordinate activities of bladder smooth muscle,
plus striated & smooth muscle of the urethra
what are the two phases that the bladder switches between for the micturition reflex?
storage phase (as the bladder fills pressure stays low)
voiding phase (voluntary signals relax external sphincter, autonomic contraction of detrusor muscle)
what are the steps in the micturition reflex?
bladder fills
sensory nerve endings detect detrusor muscle stretch
neuronal input to dorsal spinal cord
periaqueductal grey matter
cortex frontal lobe (social appropriateness)
switch
medial pontine micturition centre
motor nerves
ventral spinal cord
detrusor muscle contracts
external sphincter relaxes
what is the pudendal nerve?
voluntary constriction of external sphincter to prevent micturition
what does the sympathetic NS do to the bladder?
relaxes destrusor muscle and constricts internal sphincter
what does the parasympathetic NS do to the bladder?
contracts detrusor muscle and relaxes internal sphincter
what does the somatic NS do to the bladder?
voluntary constriction of external sphincter to prevent micturition
what is the process of filtration in the bowmans capsule?
1) glomerular capillary pressure, the blood pressure within the glomerulus, moves fluid from the blood into the capsule
2) capsular pressure, the pressure inside the bowmans capsule, moves fluid from the capsule into the blood
3)colloid osmotic pressure, produced by the concentration of blood proteins, moves fluid from the bowmans capsule into the blood by osmosis
4)filtration pressure is equal to the glomerular capillary pressure minus the capsular and colloid osmotic pressures
what is the vasa recta?
capillaries that dip into the medulla helping to remove water leavig the loop of henle
