Unit 2.6 The Kidney

What is osmoregulation

The maintenance of constant water levels in the body fluids of an organism.

Why is osmoregulation important [2]

• Prevent cell bursting or shrinks when water enters or leaves by osmosis

• Cellular reaction occurs in aqueous solution therefore water levels affects concentration and the rate of reaction in cells

Describe the function of the kidney

• Remove toxic waste substances from the body

• Maintenance the water levels of body fluids

• Control the volume and concentration of urine

Label

What is the function of renal artery

Supplies blood to the kidney and filter the blood

What is the function of the renal vein

Drains blood from the kidney and bring oxygen for cells

What is the function of the ureter

Takes urine to the bladder from kidney

What is the function of the urethra

Release urine from the bladder, out of the body

What is a nephron

Functional unit of the kidney where filtration and selective re absorption takes place

Label

What are the 3 stage involved in the formation of urine

1. Filtration

2. Selective reabsorption

3. Osmoregulation

Describe filtration in the kidney

• Blood flows through the capillary knot under high pressure, small molecules (urea and glucose) water and salt are filtered out of the blood into the Bowman’s capsule

Why is there a build up of pressure in the capillary knot?

Arteriole leading into the capillary knot is wider than arteriole taking blood from the capillary knot

Why do large molecules such as proteins and rbc remain in the blood

They are too large to fit through the pores in capillary walls

Which substances are selective reabsorbed from the nephron tube

• Glucose

• Some water

• Some ions

What happens to the molecules not selectively reabsorbed in nephron tube

They travel down the kidney tubules as urine and are transported to the bladder via the ureter, here they are stored and eventually excreted

If blood water level become too high, the kidney produces more __ urine

Dilute

If blood water level become too low, the kidney produces more __ urine

Concentrated

How is the concentration and volume of urine controlled

Controlled by secretion of ADH

What produce ADH?

Pituitary gland

Describe how ADH affects the kidney

ADH cause the kidney to reabsorbed more water into the blood, so more concentrated urine is produced

What does the composition of blood contain

• Cells

• Proteins

• Water

• Glucose

• Salts

• Urea

what does the composition of filtrate contain

• water

• Glucose

• Salts

• Urea

What does the composition of urine contain

• water

• Salts

• Urea

What may blood or cells in the urine indicated

Kidney diseases

How can kidney failure be treated [2]

• Kidney dialysis

• Kidney transplant

What is kidney dialysis

A machine artificially filters a patient’s blood

What is the dialysis fluid called

Dialysate

How does kidney dialysis work

• The selective permeable barrier separates the patient’s blood from dialysate

• Materials exchanged across the barrier such as urea and water moves out of the blood into the dialysis fluid

• Large cells and proteins remain in the blood

Describe the composition of dialysate

• Fewer salts and water than patient’s own blood so excess salts and water diffuse out of the blood into the dialysate

• No urea

Advantage of kidney dialysis

• No surgery needed

• Can undergoes kidney dialysis while waiting for a donor kidney

What does a kidney transplant involves

Taking a kidney form a living donor or someone recently pass out and implanting it into the patient

What does a kidney transplant involves

Taking a kidney form a living donor or someone recently pass out and implanting it into the patient

What is meant by kidney rejection?

The immune system detects the foreign tissue and attacks it

What is meant by kidney rejection?

The immune system detects the foreign tissue and attacks it

What precaution are taken to minimise the risk of rejection

• Tissue typing ensures that the transplanted organ is compatible with the recipient

• Immunosuppressant drugs helps prevent the immune system from rejecting the organ

Advantage of kidney transplant

• More of a permanent solution than

Advantage of kidney transplant

• More of a permanent solution than kidney dialysis

• Improve patient’s quality of life

Disadvantage of kidney transplant

• Difficult to find a donor

• Requires surgery

• Have a limited life span

• Risk of organ rejection

• Immunosuppressants increase the risk of their infections

Describe the stimulus that will secreted ADH

The low content of water in blood

What waste product do excess broken down of amino acid produce, how is it removed and why is it harmful for human

Excess broken down of amino acid can produce large volume of ammonia. This is harmful for human body as ammonia is toxic, so it is converted to urea in the liver and then eventually excreted out

Where are nephrons positioned at

Across the cortex and the medulla