Renal Flashcards
What are the components of the urinary system (4)
- paired kidneys
- paired ureters
- urinary bladder
- urethra
What are the 5 functions of the kidney?
- filter blood plasma
- regulates osmolarity of body fluids, BV, BP
- secretes renin and erthyropoietin
- detoxifies
- gluconeogenesis
The kidney filters the blood plasma by?
eliminating waste
What are the nitrogenous wastes removed by the kidney? (3)
- urea
- uric acid
- creatinine
How is urea produced?
proteins->amino acids-> NH2 removed->to form ammonia
liver converts to urea
uric acid is a ____ catabolism while creatinine is a ______ catabolism
nucleic acid; creatinine phosphate
when fluids leave the cardiovascular system, they go to?
kidneys
creatinine phosphate is an energy source stored in the?
muscle
uremia
toxic effects as wastes accumulate
What are the 4 systems used to excrete waste from body fluids?
- respiratory
- integumentary
- digestive
- urinary
kidneys are positioned ______; which means?
retroperitoneal; behind the lining of the abdominal wall
covering of the kidneys:renal fascia? adipose capsule?renal capsule?
renal: binds to the abdominal wall
adipose: cushions the kidney
renal: encloses kidney like cellophane wrap
what are the parts of the renal nephron? (3)
- corpuscle
- tubule
- collecting system
the functional unit of the kidney?
nephron
the renal corpuscle contains?
- glomerulus
- bowman’s capsule
the portal system in the renal corpuscle contains?
vasa recta and peritubular capillaries
What are the supporting cells of the renal corpuscle?
mesangila cells
Which arteriole is biggest?
afferent
What are the layers of bowman’s capsule? (3)
visceral
parietal
capsular
the renal tubule contains? (3)
- proximal convoluted tubule (PCT)
- loop of henle
- distal convoluted tubule (DCT)
which convoluted tubule passes through the afferent and efferent arterioles?
DCT
The PCT and DCT is the site of? (2)
reabsorption
secretion
PCT reabsorbs (4)
- nutrients
- ions
- volume
- escaped plasma proteins
what is the purpose of the loop of henle?
to concentrate urine
DCT secretes? (2) reabsorbs? (2)
acid, drugs, toxins
K (selectively)
Na and Ca
water
what is the purpose of the papillary duct, calyx, and pelvis?
to direct urine towards the bladder
juxtaglomerular apparatus contains? (2)
distal tubule
afferent and efferent arterioles
what type of cells are in the juxtaglomerulus apparatus? (2)
juxtaglomerulus cells in the afferent arterioles
macula densa in the DCT
what is the function of the juxtaglomerulus cells?
to release renin and erythopoietin
what is the function of the macula densa cells of DCT?
chemoreceptors that are sensitive to changing sodium levels of the filtrate
macula densa:
a _____ in the osmolarity (sodium) triggers a release in renin, which then releases ___
decrease; aldosterone
what are the 2 types of the nephrons?
cortical
juxtamedullary
cortical nephrons represent ____ percent of nephrons and have ____ loop of henle
85%; short
juxtamedullary nephrons have ____ loop of henle and the corpuscle is located at ______ junction
long; cortex-medulla
what processes are required for urine formations? (3)
- glomerular filtration
- tubular reabsorption
- secretion
the kidneys are ___ percent of body weight, but use about ____ percent of oxygen at rest
1% and 20-25%
why is urine produced?
to maintain blood volume and composition
In glomerular filtration, there are filtration slits between ______. What type of basement membrane does it have?
podocytes (cells that wrap around the capillaries of the glomerulus); lamina densa
the filtration membrane determines what stays and what can go. the basement membrane has the smallest _____. what determines the cutoff?
cutoff. plasma minus protein
glomerular filtration rate? how much is it?
total amount of filtrate formed per minute by the kidney; 125mL per minute
what 2 factors result in high GFR?
- glomerulus is fenestrated capillaries (PERMEABLE)
- blood pressure is 60mmHg (afferent arteriole)
GFR is controlled by the same forces that control filtration and reabsorption at the capillary bed? what are they?
hydrostatic pressure
osmotic pressure
If GFR is elevated?Below?
- can’t absorb sufficient solutes and water
- blood levels of waste increase
GFR abnormalities
high GFR->
low GFR->
high: urine output rises->dehydration, electrolyte depletion
low: wastes reaborbed
regulation of GFR is achieved by adjusting___ _____.How is this achieved? (3)
blood pressure
- autoregulation
- hormonal regulation
- sympathetic regulation
autoregulation
the ability of the kidney to maintain a relatively stable GFR in spite of changes in MAP by changing arteriole diameter
if glomerular blood pressure increase, _____
afferent arteriole walls stretch and trigger smooth muscle to contract (relax efferent arteriole)
if glomerular blood pressure decrease, _______
drop the stretch in the afferent arteriole and it relaxes (constrict efferent arteriole)
Renin/Angiotensin II system
works to increase systemic blood volume and pressure to restore back to normal GFR
Renin is released when (3)
- drop in glomerular blood pressure
- low osmolarity of filtrate of DCT
- sympathetic activity to the JG apparatus
effects of renin at the peripheral capillary bed? (2)
- triggers vasocontriction and increase BP
- release of aldosterone (Na and water reaborption->increase BV and BP)
effects of renin at nephron?
constricts the efferent arterioles
effects at CNS?
-triggers release of ADH (antiduretic hormone; increase water reaborption)
atrial natriuretic peptide hormone is released to
lower blood volume and thus pressure
what are the effects of atrial natriuretic peptide hormone? (3)
- triggers dilation of afferent arteriole
- blocks affects of ADH
- elevated GFR->increase urine flow and lower BV and BP
Which type of regulation overrides all other forms of GFR regulation?
sympathetic
during low sympathetic activity?
release renin to increase GFR
during moderate sympathetic activity? (3)
- drop in urine production due to vasocontriction
- offset by autoregulation and hormonal regulation
- GFR is maintained
during high sympathetic activity? (3)
- NOT offset by autoregulation or hormonal regulation
- urine production approaches zero
- large drop in GFR
tubular reabsorption
removes useful solutes from the filtrate, and returns it back to the blood
tubular secretion
removes additional wastes from the blood, adds them to the filtrate
what gets reabsorbed back into the blood 100% during tubular reaborption?
glucose and amino acids
how is material returned to the peritubular capillaries?
diffusion and osmosis
why is movement into the peritubular capillaries easy? (3)
- high colloid osmotic pressure
- low blood pressure (narrow efferent arterioles)
- slow flow rate
PCT (2)
- reabsorbs a greater variety of chemical than other parts of the nephron
- reabsorbs 65-70% of filtrate to peritubular capillaries
transcellular route
through epithelial cells of PCT
paracellular route
between epithelial cells of PCT
during tubular reabsorption, the PCT reabsorbs what? (7)
- sodium (65%)
- glucose (100%)
- amino acid (100%)
- water (65-70%)
- cations
- anions
- nitrogenous wastes
tubular reabsorption of sodium?
active transport
tubular reabsorption of glucose and amino acid?
Na dependent translocator
what is the primary function of the loop of henle?
to enable the collecting duct to concentrate the urine an conserve water
Loop of Henle: recaptures ____ and returns it to the renal _____
NaCl; medulla
The descending limb of the loop of henle? (2)
- reabsorbs water but not salt
- tubular fluid is hypertonic
The ascending limb of the loop of henle? (3)
- reabsorbs Na+, K+, and Cl-
- impermeable to water
- tubular fluid is hypotonic
As you ____ from the cortex->medulla, the kidney becomes more….
saltier
role of the vasa recta?
- countercurrent exchange (descending picks up salts and ascending picks up water)
- opposite of loop of henle
what percentage of original volume is left after tubular reabsoption and secretion at the DCT?
10-15%
effects of aldosterone at the DCT?
-trigger the production and insertion of a sodium channel at basal membrane-> stimulate NaK ATPase
effects of calcium at the DCT?
-regulated by the parathyroid hormone and calcitriol-> stimulate production of Ca ATPase (1 Ca for 2 acids)
reabsorption at the collection system:
- Na?
- Water?
- Urea?
Na: aldosterone sensitive areas
water: antidiuretic sensitive area of the nephron
urea: collects at the bottom of the loop
tubular secretion from the peritubular capillaries into the tubule:
potassium?
hydrogen ion?
K: aldosterone sensitive
hydrogen ion:H+ goes into filtrate and exchange for Na
- aldosterone sensitive
normal volume of urine
1 to 2L per day of urine
polyuria
> 2L per day of urine
anuria
0 to 100 mL per day of urine
composition and properties of urine? (3)
- almost colorless
- acidic (4.5-8.2)
- odor (urea->ammonia)
diabetes mellitus I
can’t produce insulin
diabetes mellitus II
- have lots of insulin, but body doesn’t recognize it
- adult onset
diuretics
effects?
uses?
- urine output is increased, blood volume is decreased
- hypertension and congestive heart failure
