The Kidney - F214 OCR

The basic information about the kidney, hope it is helpful:)

HideShow resource information
Preview of The Kidney - F214 OCR

First 79 words of the document:

The Kidney
The role of the kidney is to remove waste products from the blood and produce urine.
Each kidney is supplied with blood from the renal artery and is drained from the renal
vein. Urine passes down the kidney through the ureter to be bladder were it is stored
before release. It then travels down the urethra.
The nephron
Kidneys are made up of millions of tiny tubules called Nephrons.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Each nephron starts in the cortex. In the cortex, capillaries form a knot called the
Glomerulus. This is surrounded by the Bowman 's capsule. This leads on to the
proximal convoluted tubule, then the loop of henle. This carries on to the distal
convoluted tubule and then to the collecting duct
Blood flows into the glomerulus through the afferent arteriole; it is wider than
the efferent arteriole which takes blood away. This increases the pressure of
the blood moving away.…read more

Page 3

Preview of page 3

Here's a taster:

Basement membrane ­ is made of collagen fibres and gylcoprotiens which act
as a filter and stop larger molecules getting through, such as proteins, red
blood cells and glucose.
Endothillium ­ has narrow gaps between so that the plasma can get through.
Podocytes ­ have finger like projections called major processors these ensure
that there are gaps between cells. Fluid from the blood can pass through these
into the Bowman's capsule.…read more

Page 4

Preview of page 4

Here's a taster:

Inorganic ions
That means that what is left is red blood cells and proteins.
Selective Reabsorption
As blood moves along the nephron substances are removed and reabsorbed back into
the blood. Most reabsorption (around 85%) occurs in the proximal convoluted tubule.
All glucose, amino acids, some salts and some water is reabsorbed.
1. The sodium- potassium pumps remove sodium ions from inside the cells lining
the proximal convoluted tubule. This reduces the amount of sodium ions in the
cell cytoplasm.
2.…read more

Page 5

Preview of page 5

Here's a taster:

As the Glucose and amino acid concentration rises within the cell it raises the
concentration this allows them to diffuse back into the tissue fluid, these then
diffuse back into the blood and are carried away.
4. Reabsorption of salts makes the surrounding cells water potential higher than
inside of the cell so water moves in down a water potential gradient into the
tubule. This means that the water potential in the tubule fluid increases.…read more

Page 6

Preview of page 6

Here's a taster:

Water Reabsorption
The role of the loop of henle is to create really low water potential in the tissue of the
medulla. This ensures that even more water can be reabsorbed from the fluid in the
collecting duct.
The loop of henle consists of a descending limb that descends into the medulla and an
ascending limb that ascends back into the cortex. This arrangement allows salts to be
transferred from the ascending limb to the descending limb.…read more

Page 7

Preview of page 7

Here's a taster:

How does this happen?
As the fluid in the tubule travels down the descending limb into the medulla the water
potential becomes lower, more negative. This is because of diffusion of sodium and
chloride ions from surrounding tissues and loss of water through osmosis.
Then as the tubule fluid travels up the ascending limb the water potential becomes
more positive.…read more

Page 8

Preview of page 8

Here's a taster:

This arrangement is known as hairpin countercurrent multiplier. This is to increase the
efficiency of salt transfer from the ascending limb to the descending limb, this cause a
build-up of salt in surrounding tissue fluid.…read more

Page 9

Preview of page 9

Page 10

Preview of page 10

Here's a taster:

Osmoregulation is the control of water and salt levels in the body. Water is gained
from food, drink and metabolism but some is lost in urine, faeces and sweat.
The permeability of the walls of the collecting duct can be changed according to the
needs of the body, they respond to a hormone called antidiuretic hormone (ADH) in
the blood.
Cells in the cell membrane have receptors for this hormone, ADH binds to this
receptor and a series of enzyme reactions take place.…read more


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »