Urinary system and water balance Flashcards
The cleft in the kidney where nerves and blood vessels connect to the kidney is called the:
Hilus
The smallest of the branches off the renal artery, that send blood directly into the afferent arterioles of the glomeruli, are called ___________ arteries
Interlobular
The first part of the nephron tubule that collects the filtrate from the glomerulus (and is part of the renal corpuscle) is the:
Bowman’s capsule
In which of the major physiological processes of the kidney are the peritubular capillaries (and vasa recta) playing a major role?
reabsorption and secretion
Which type of nephrons are important in producing the most concentrated urine?
juxtamedullary
What hormone is produced by the kidneys in response to low blood pressure?
renin
What are examples of normal constituents of urine?
Na+ urea H+ water
Explain the factors that cause an increased outflow of filtrate from the glomeruli (as compared to other capillary beds elsewhere in the body)
- High hydrostatic BP present in glomeruli
- lots of surface area
- permeability - fenestrated capillaries
- regulation of GFR (glomerular filtration rate) by JGA
what conveys urine to the bladder
ureters
what are the smooth muscle contractions that propel urine called
peristalsis
what prevents back flow in the ureters
the bladder filling
“temporary urine storage”
bladder
anatomical features of the bladder
smooth, collapsible, muscular - retroperitoneal
very distensible - has rugae
what type of epithelium does the bladder have
transitional epithelium/ mucosa
thick muscular layer
How does the bladder fill
from bottom to top, ureters open into the bladder near the bottom
thin muscular tube that carries urine from the bladder to outside
urethra
What type of epithelium make up the urethra
transitional > columnar > stratified squamous
length of urethra in male vs female
20cm for males and 3-4 for females (UTI are more common)
surrounds urethra - skeletal muscle - voluntary
external urethra
micturition and voiding also mean
urination
inside the bladder/urethra involuntary
internal urethral sphincter
process of urination
distention of the bladder > stretch receptors > impulses to sacral spinal cord
where is the brain does the decision to void happen
cerebral cortex - micturition center in pons
volume of plasma cleared of a substance in 1 min
renal clearance
what does renal clearance determine
GFR
max renal clearance
~140 ml/min
maintenance of homeostatic balance of bodily fluids
fluid, electrolyte, acid-base balance
fluid compartments in the body and where they are
intracellular fluid compartment -in the cells
extracellular fluid compartment - surrounding each body cell
Percentage of intracellular fluid
67%
percentage of extracellular fluid (overall, interstitial fluid, and plasma)
Overall 33%
interstitial fluid 80%
plasma 20%
what separates body fluids into the fluid compartments
selectively permeable cell membranes
fluids are in constant motion between what three compartments
Plasma, interstitial fluid, and tissue cells
T or F all dissolved solutes contribute to osmotic activity
True
water moves DOWN its concentration gradient to an area of …
greater osmolality
electrolytes have greater
osmotic power (dissociation)
Na+ and Cl- are solutes in …
extracellular fluid
K+ and phosphate are solutes in …
intracellular fluid
net water flow is ..
the alteration of solute concentration between two compartments
Main function of the urinary system
filters blood to remove toxins, wastes, and excess ions
- regulate volume and composition of blood
- maintain water and electrolyte balance
Where are the kidneys in the body
retroperitoneal - in lumbar abdomen
Kidney cleft is called the …. and houses
renal hilus
ureters, blood supply, lymphatics, and nerves
internal regions of the kidneys
cortex, medulla, and pelvis
order of blood through the kidneys starting from the aorta (arcuate, interlobular, interlobar, renal, segmental)
renal > segmental > interlobar > arcuate > interlobular
Afferent arteriole is … and efferent arteriole is … (which sends blood to the glomerulus
Afferent - IN (sends blood to the glomerulus)
Efferent - OUT
capillary beds are leaky, if not imm - resorbed by blood and lymphatic fluid
exchange between plasma and interstitial fluid
- ions move selectively through plasma membranes
- most substances more unidirectionally but water moves freely
- plasma links the internal + external environments
exchange between interstitial and intracellular fluid
what links the external world to the internal world
blood plasma
what is the most important biological solvent and the main component of all body fluids
water
what triggers thirst and stimulates ADH release (kidneys produce concentrated urine)
Rise in plasma osmolality or drop in volume
what inhibits thirst and ADH
drop in plasma osmolality
Thirst mechanism (in the brain)
hypothalamus
Plasma proteins, blood cells, ions, nutrients, oxygen and waste products are all components of what
Arterial blood entering the kidney
amino acids and glucose are classified as
nutrients
Na+, K+, acids and bases are classified as
ions
Venous blood leaving the kidney contains what
nutrients and small amounts of oxygen
blood processing, urine forming, filtration units
nephrons
ball of capillaries - fenestrated to allow filtrate to pass
glomerulus
glomerular/bowman’s capsule - proximal tubule - loop of henle - distal tubule
renal tubule
filtrate is processed through the tubule before contents pass to the …
collecting duct
what is the correct order (papillary ducts, collecting ducts, calyces)
collecting ducts - papillary ducts - calyces
two capillary beds of the nephron
glomerulus and peritubular
produces filtrate and is very high in pressure
the glomerulus (fed and drained by arterioles)
reclaims filtrate
peritubular capillaries
what cells sense blood pressure and secrete renin
juxtaglomerular
what tubule cells sense concentration
macula densa
the glomerulus filtration membrane allows passage of what
water and small solutes
the glomerulus filtration membrane prevents passage of what
plasma proteins and cells
capillary pores are also called
fenestrations
what forces water and other molecules through the glomerular filtration membrane
hydrostatic pressure
the amount of water we lose a day just to carry away waste/urine/losses through skin and lungs
obligatory water loss 500mL+
how soon after hydration is ADH inhibited
~30 min
kidneys begin to eliminate excess water
filtrate (blood plasma minus proteins turns into what
urine
major processes in urine formation/blood balance
- glomerular filtration
- tubular reabsorption
- tubular secretion
ADH stands for what
antidiuretic hormone
what does ADH do
causes kidneys to release less water
normal glomerular filtration rate
~125 mL/min (180L/day)
regulation critical of the glomerulus means
too slow - waste remains
too fate - substances lost
renal autoregulation, neural controls, renin-angiotensin system control what
glomerular filtration rate
hypotonic hydration
over hydration
edema
swelling; interstitial fluid
caused by increased BP or inflammation
what controls water distribution in the body
salt; water follows salt
does salt exert strong osmotic pressure
yes
NaCl and NaHCO3 account for how much of all extracellular fluid
90-95%
essential minerals, exert a greater effect on osmosis, help maintain acid-base balance, carry electrical current are the four general functions of
electrolytes
internal kidney pressure adjustment
renal auto regulation
most Na+ in filtrate is reabsorbed to what
the blood 90% without influence
sodium balance is influenced by
aldosterone, ADH, neural controls, and ANP
adrenal cortex hormone
aldosterone
-causes remaining sodium to be reabsorbed
which tubule is more active (proximal or distal)
the proximal tubule
which tubular turns secretion from peritubular capillaries into filtrate, disposes of drugs and waste, and controls blood pH
the proximal tubule
regular pH of urine
4.5-8 if it is abnormally low there could be a kidney malfunction
what part of the brain controls ADH levels
hypothalamus (osmoreceptors)
ANP stands for what
atrial natriuretic peptide
what peptide reduces BP, blood volume and inhibits vasoconstriction, sodium retention, and water retention.
ANP
what do glucocorticoids do
raise BP and promote edema
salts, acids and bases dissociate in water into
electrolytes
what is the main intracellular cation
potassium
if the balance of potassium is off it causes
reduced excitability of neurons and muscle
it is also sensitive to pH levels
85% of potassium is reabsorbed from filtrate but what happens to the extra
it is secreted in urine
the balance of what is regulated by the parathyroid glands and calcitonin
calcium
how much calcium is resorbed to blood
98%
what element in ECF has to do with clotting, membrane transport, and muscle contraction
calcium
what electrolyte activates coenzymes in glucose and protein metabolism
magnesium
ICF pH
7.0
ECF pH
7.3-7.4
blood pH is above 7.45
alkalosis
blood pH is below 7.35
acidosis
chemical buffer systems, respiratory mechanisms, and renal mechanisms all regulate blood proton ()
H+
what do chemical acid-base buffers do to regulate H+
binds to H+ when pH drops and releases H+ when pH rises
what do respiratory buffers do to regulate H+
increases CO2 to activate chemoreceptors and increases respiratory rate
what do renal buffers do to regulate H+
reabsorbs or excretes bicarbonate ions
