Renal System Flashcards
Function of kidney
Excretion - urination, excrete end products of metabolism and excess, inorganic substances
Homeostasis regulation - electrolyte and water homeostasis, acid base balance
Endocrine function- synthesis of hormones, target site for hormone
Structure of kidney
Renal cortex - contains capillaries
Renal Medulla - pyramids contain calcyces to form calyx- form renal pelvis
- renal pelvis collects urine
- transports urine to ureters
Function of kidney
Responsible for processing blood and sifting waste product and excess water
What is nephrons ?
Nephrons are urine forming units of kidneys
What are the two types of nephrons ?
Cortical nephron
Juxtamedullary nephron
Cortical nephron function
Shorter in length
Located in cortex
Performs most of reabsorptive secretory functions of kidneys
Juxtamdeullary function
Concentrates urine
Longer in length runs through medulla
What is the glomerular capsule?
Known as bowman’s capsule
Located at beginning of nephrons in kidney
Glomerulus
Cluster of capillaries involved in initial filteration of blood to form urine
Glomerular capsule function
Located in cortex
Glomerular capillaries consist of endothelium with large diameter pores
Macula densa(cells) detect levels of chloride and sodium ions
Juxtaglomerular cells secrete renin
Proximal convoluted tubule function
Reabsorption and secretion
What are the substances reabsorobed in proximal convoluted tubule?
Organic nutrients
Ions
Water by osmosis
Descending limb of loop of Henle
Are thin with no microvilli and few mitchondria and and are permeable to water but not ions NA AND CL
Ascending limbs of loop of henle
They are thick and consist of microvilli and lots of mitchondria and are not permeable to water but permeable to ions
What makes the loops countercurrent multipliers ?
Thin descending and thick ascending limbs
Renal function ?
Work carried out by kidney
Glomerular filteration rate :
Measure of rate at which kidneys filter blood to remove waste products and excess substances from blood
If the GFR is too high …
Needed substances can not be reabsorbed quickly enough and lost in urine
If GFR is too low…
Everything is absorbed even waste products
What does glomerular filteration pressure depend on?
Glomerular blood hydrostatic pressure
Capsular hydrostatic pressure
Blood colloid osmotic pressure
How does countercurrent multiplier system work?
Pushing of sodium and chlorine ions from ascending limbs increase osmotic concentration of peritubular fluid making it easier for osmotic flow of water from descending limbs into periturblar fluid
What is counter current ?
Exchange between fluid moving in opposite directions
Fluid in descending limbs move to renal pelvis and ascending limbs move towards cortex
Explain the ion reabsorption in ascending limb.
NA, K AND CL ions are transported out of tubular fluid- active transport
K and CL are pumped into intestinal fluid
NA is pumped out in exchange for K.
K diffuses back into lumen of tubule through K leak channels
Na and k are lost into pertitubular fluid
Distal convoluted tubule function
Regulates electrolyte balance- Na k and Cl
Reabsorption of water, Na and Ca ions from tubular fluid- transported across DCT
Na reabsorbed in exchange for K by pump by aldosterone
Ca also reabsorbed in DCT- by parathyroid hormone
