nephrons a level biology

osmoregulation

what is the definition of osmoregulation

homeostatic control of the water potential in the blood

what is the fibrous capsule

outer membrane that protects the kidneys

what is the cortex

lighter coloured outer region, made of the renal capsule, convoluted tubules and blood vessels

what is the medulla

darker coloured inner region, made up of the loop of Henle, collecting duct and blood vessels.

what is the renal pelvis

its a funnel shaped cavity, collects urine into the ureter

what is the ureter

tube that transports urine to the bladder

what is the renal artery

supplies the kidneys with blood via the aorta

what is the renal vein

takes blood away from the kidney via the vena cava

what is a nephron

its a functional unit of the kidney

• its a narrow tube, up to 14mm long

what is the Bowmans capsule

it is a cup shaped structure, surrounds a bundle of blood capillary called the glomerulus.

• the inner layer of the Bowmans capsule is made up of specialised cells called PODOCYTES.

what is the proximal convoluted tubule

series of loops that are surrounded by blood capillaries.

• walls are made of epithelial cells which have microvilli.

what is the loop of Henle

hair pin shaped, extends from the cortex to the medulla then back to the cortex.

• surrounded by blood capillaries

what is the distal convoluted tubule

series of loops surrounded by less blood capillaries than the proximal convoluted tubules.

• walls made of epithelial cells.

what is the collecting duct

its a tube where many distal convoluted tubules join from many nephrons and empty their urine.

• walls made from epithelial cells

• it becomes wide from the bottom as it connects to the renal pelvis of the kidney

what is the afferent arteriole

tiny blood vessel which arrises from the renal artery and it supplies the nephron with blood. the afferent arteriole enters the Bowmans capsule to form the glomerulus.

what is the glomerulus

many branched knots of capillaries which force fluid out of the blood.

• glomerulus capillaries recombine to form the efferent arterioles.

what is the efferent arteriole

tiny blood vessels that leave the Bowmans capsule.

-have a smaller diameter than the afferent arteriole

this is to increase the blood pressure within the glomerulus

• the blood leaves the Bowmans capsule.

• branches into the blood capillaries.

what is the blood capillaries

surrounds the proximal convoluted tubule, loop of Henle, distal convoluted tubule.

• reabsorbs mineral ions, glucose and water

• blood capillaries merge into venules which then branch off into the renal vein.