L83- Renal Physiology Flashcards
what organs does the urinary system contain?
- kidney
- bladder
what is the function of the kidney?
- excrete metabolic products and xenobiotics
- regulate body fluids osmolality and volumes
- electrolytes balance
- acid-base balance
- endocrine function
what is xenobiotics?
anything in the body that shouldn’t be there egg, poisons and drugs
what does efforent mean?
narrower and out
what does afferent mean?
thicker and in
what % of blood is flitered out?
10-20% the rest goes on this occurs in the proximal tubular
wjhat side is the glomerulus?
proximal end
what are the 8 segments of the nephron?
-Proximal convoluted tuble
-Proximal straight -Descending Loop of Henle (thin)
-Ascending L of H (thin)
-Ascending L of H (thick)
-Distal convoluted
-Cortical collecting duct
• Medullary collecting duct
what % of cariac output goes to the kidney?
25%
how much is filterd from the kidney in a day?
1.5L
what 3 processes account for renal excretion?
- Glomerular Filtration
- Tubular Secretion
- Reabsorption from tubule
urinary excretion rate=
filtration rate + secretion rate - re-absorption rate
how do things leave capillaries?
becasue capillaries are leaky components and allow the passage of plasma com
what is glomerular filtration?
occurs the glomerulus where 10-20% is filtered the rest passes into the efferent arteriole.
what type of substance can be filtered during glomerular filtration?
- small molecules lie glucose amino acids.
- unbound drugs can also be filtered
what type of substance can’t be filtered during glomerular filtration?
- protein bound drugs
- proteins
what is the glomerular filtration rate?
- is a measure to assess kidney function
- normal GFR is approx 120ml/min
what is the kinky tubule lined with?
epithelium they have tight junctions some are leaky some aren’t
what is the basolateral surface
on the blood side
what is the proximal tubule causing tubular secretion?
where 80-90% passes to peritubular capillaries in primal tubule
what are the active transporters called in the proximal tubule?
OAT (Organic acid transporter) and OCT (organic cation transporter)
what occurs in the proximal tubule according to water movement?
Water movement via the paracellular pathway takes solutes with it (Na+, Cl-)
what happens in the Loop of Henle?
reabsorption of water
explain what are the different water permeabilities of the Loop of Henle?
- descending limb is permeable to water
- ascending lomb is impermeable to water
what is occurring in the medulla?
osmotic gradient and water is moving out of the descending limb
what occurs in the ascending limb?
Na+ and Cl- move out and is reabsorbed without the movement of water
what are some facts about the distal tubule?
- very permeable to water
- Na+ and Cl- is reabsorbed further dilutes the tubular fluid
how does water enter the collecting ducts/tubule?
through aquaporins
what are some facts about the collecting ducts/tubule?
passes through the medulla where there is high osmolarity
where does dilute or concentrated urine occur?
in the collecting duct/tubule and is controlled by hormones.
what are the 2 hormones that are responsible for dilute or concentrate urine?
- aldosterone
- anti-diuretcis hormone (ADH)
what are some facts about aldosterone?
- secreted from the adrenal cortex
- increased the number of active epithelial Na+ channels in the collecting duct and promotes Na+ and water reabsorption
- increases blood volume
what are some facts about anti-diuretics hormone ADH??
- SECRETED FROM THE POSTERIOR PITUITARY GLAND
- INCREASES NUMBER OF AQUAPORINS INCREASES WATER REABSORPTION
- LEADS TO MORE CONCENTRATED URINE
- ALCOHOL INHIBITS SECRETION OF ADH
what are some facts about DIURETICS?
- act to increase production of urine
- they work blocking the reabsorption of ions, less water is also reabsorbed
