Kidney Function Flashcards
What are the functions of the kidneys ?
- maintain homeostasis
- excretion
- hormonal
- metabolic
What does the kidneys excrete ?
- nitrogenous urea
- creatine
What are the hormonal functions of the kidney ?
- synthesises renin
- controlls BP
- synthesises erythropoietin
What does the synthesis of erythropoietin stimulate ?
Stimulates erythrocytes production in bone marrow
Regulates 02 carrying capacity of blood
What does the kidneys metabolise ?
Vitamin D
What do the kidneys filter
Small molecules from blood plasma
What do the kidneys selectivly reabsorb ?
- water
- some molecules from ultrafiltrate
What do the kidneys ?
Renin
Erythropoietin
H+ ions
Describe the kidneys structure :
- has outer cortex
- inner medulla
What are the medullary pyramids ?
Cone shaped masses of medullary substance
Project into subdivisions of the renal pelvis
What is the hilum ?
- site of entry and exit of the renal blood vessels and ureter
What is the renal corpsucle ?
Made up of Bowmans capsule
Glomerulus
What is the renal tubule ? What does it consist of ?
- proximal convoluted tubule
- loop of henle
- distal convoluted tubule
- collecting tubule
What are the 3 layers the plasma filtrate passes through before entering the renal tubule ?
- capillary endothelium
- glomerular basement membrane
- podocytes
What is the juxtaglomerular apparatus ?
Specialisation of the afferent arteriole and distal convoluted tubule
Regulates blood pressue via renin-angiotensin-aldosterone system
What is the macula densa ?
An area of large closely packed tall epithelial lining cells adjacent to the juxtaglomerular apparatus
What are juxtaglomerular cells ?
Specialised smooth muscle cells of the afferent arteriole wall that contain and secrete renin
What are lacis cells ?
- derived from mesangial cells
- responsible for erythropoietin synthesis and secretion
What do principal cells do ?
- actively reabsorp Na
- secrete K
What do intercalated cells do ?
- important for acid-base homestasis
- secrete H+
- reabsorb HCO3 and K+
What is the ureter ?
- muscular tube that conducts urine from the kidney to the bladder
What moves the urine down the ureter ?
Moves via peristaltic action of ureteric wall
What 2 layers make up the ureter ?
- longitudinal
- circular
Describe the longitudinal layer of smooth muscle :
- inner layer and elongated spiral
Describe the circular layer of smooth muscle :
- outer layer
- tight sprial
What lines the ureter ?
- transitional epithelium
- deep lamina propria rich in collagen
Describe the structure of the bladder :
- has 3 smooth muscle layers :
Inner longitudinal
Outer circular
Outermost longitudinal - lots of elastic fibre
