2- The anatomy and physiology of the kidney Flashcards
What is the renal capsule
Fibrous capsule around the kidney
What is the renal Cortex
The outer region of the kindey
What is the renal medulla
Inner region; composed of renal pyramids
What is the renal columns
Extension of cortex that dip into the medulla
What is the renal pelvis
Funnel-shaped sack; superior end of the ureter
What are minor and major calices
They are small and large tubes that merge to form the renal pelvis
What is the function of the renal artery
Branches off abdominal aorta, enters kidney through hilum
What is the function of segmental arteries
Branche off renal artery
What do interlobar arteries do
Branch off segmental arteries, flow between renal pyramids
What do arciform arteries do
Branch off interlobar arteries and arch around the renal pyramids
What do cortical radiate arteries do
Branch off arcuate arteries
What makes up the renal corpuscle
Glomerulus
Bowmans Capsules
What is the renal tubule and what is its function
It extends from the bowman’s capsule to the collecting duct, where distal tubules of several nephrons empty into a collecting duct.
The collecting duct continues through the medulla and drains through the renal papilla into a major calyx.
What are the two types of nephrons in the kidney.
Cortical nephron
Juxtamedullary nephron
What are structural features of cortical nephrons
Lie almost completely in renal cortex
Have short nephron loops
Renal corpuscles located near surface of kidney
What are the structural features of juxtamedullary nephrons
Have long nephron loops, that extend deep into the medulla
Renal corpuscles lie deep in renal cortex
Important in regulating water balance and urine excretion
What is the function of the afferent arteriole
Branches off the cortical radiate arteries, each enters a different nephronW
What is the function of the glomerulus
Cappilary cluster that branches from afferent arteriole (filters blood in each nephron )
What is the function of the efferent arteriole
Arises from merging of glomerular cappilaries (transports blood that was not filtered by glomerulus)
What is the fucntion of the peritubular cappilaries
Branches off the efferent arteriole; surrounds renal tubules.
What is the function of the vasa recta
Branches off the efferent arteriole
Runs parallel to the tubules descending into the medulla
Forms capillary medulla networks and then return to the cortex
What is the functions of the juxtaglomerular apparatus
A structure that regulates the secretion of the enzyme renin.
Monitors and adjusts blood pressure and NaCl content of filtrate.
What is the macula dense
Tall, closely packed cells of the ascending limb
Monitors NaCl content of filtrate
What do juxtaglomerlular cells do
Vascular smooth muscle cells of the ascending limb
Monitor blood pressure
What are the 3 processes of urine formation
Glomerular Filtration
Tubular Reabsorption
Tubular Secretion
What is the process of glomerular filtration in urine formation
Performed by specialised glomerular capillaries
Water and small molecules are filtered
Filtered fluid enters renal tubules and becomes tubular fluid
What is the process of tubular reabsorption
Transfer of filtered substances from renal tubules to peritubular capillaries
Only reclaims useful substances while wastes continue to become urine
What is the tubular secretion phase of urine formation
Transfer of certain substances from peritubular capillaries to renal tubules
Adds waste products and excess substances forming urine.
What is the composition of glomerular filtrate
Mainly water
Glucose, amino acids
Urea, Uric acid, creatine, creatine
Ions
How is the net filtration pressure calculated
NFP= Forces favouring filtration - forces opposing filtration
As long as the net flitration pressure in the glomerulus is positive, filtration will occur
What are forces favouring filtration
Glomerular capillary hydrostatic pressure
What are forces opposing filtration
Glomerular capillary colloid osmotic pressure
Capsular hydrostatic pessure
What is the average adult GFR
125ml/min or 180L/day
What are the factors affecting GFR
GFR is directly proportional to the net filtration pressure, so anything that changes NFP will change GFR
Changes in diameter of afferent or efferent arteriole
