Excretory System

Question 1

What is excretion?

Answer 1

The removal of metabolic
wastes, toxins and
substances in excess of
requirement.

Question 2

What is egestion?

Answer 2

Discharge or expulsion of undigested material (food) from a cell in the case of unicellular organisms and from the digestive tract via the anus in multicellular organisms

Question 3

What is the kidney?

Answer 3

A bean shaped organ which lies in the abdominal cavity below the diaphragm on each side of the vertebral column. Their function is to filter blood.

Question 4

What is the ureter?

Answer 4

A tube that carries urine from the kidneys to the urinary bladder.

Question 5

What is the bladder?

Answer 5

A muscular sac in the pelvis which stores urine until it is ready to be discharged.

Question 6

What is the urethra?

Answer 6

A tube that connects the urinary bladder to the genitalia. Urine is discharged from here.

Question 7

What is urination?

Answer 7

The process of disposing
urine from the urinary bladder through the urethra to the outside of the body is called urination. The process of urination is voluntary. It is called micturition

Question 8

What is urine?

Answer 8

Urine consists of excess water ,
nitrogenous wastes ( urea ) , some
inorganic salts , excess substances
such as small amounts of glucose
and vitamins .

Question 9

Name the parts of the kidney

Answer 9

Cortex - Outer part
Medulla- Inner part

Question 10

What are nephrons comprised of?

Answer 10

Glomerulus, Bowman’s capsule, Kidney tubules, Loop of Henle and collecting duct

Question 11

How is urine formed?

Answer 11

Through the renal vein, blood enters the kidney which breaks into the renal capillaries. The blood enters the renal capillaries at high pressure. This means that the blood can be filtered by the glomerulus of the nephrons.

The high pressure forces the small molecules such as glucose, water, urea and ions to pass into the bowman’s capsule forming the glomerular filtrate.

At each stage, useful substances such as water and glucose are re-absorbed in the nephrons. Glucose is re-absorbed in the Proximal Convoluted Tubule and water is re-absorbed in the Loop of Henle.

Substances which are not reabsorbed form urine. Urine travels through the ureter to the bladder where it is discharged from the urethra.

Question 12

Define osmosis

Answer 12

The movement of SOLVENT particles from a region of HIGHER concentration to a region of LOWER concentration through a PARTIALLY PERMEABLE MEMBRANE.

Question 13

Define Diffusion

Answer 13

The movement of PARTICLES from a region of HIGHER concentration to a region of LOWER concentration

Question 14

What does re-absorption depend on?

Answer 14

• Diffusion
• Osmosis
• Active transport based on the body’s needs

Question 15

What does the volume and concentration of urine depend on?

Answer 15

• Water and salt intake
• Temperature
• Exercise

Question 16

Define osmoregulation

Answer 16

The process that regulates the osmotic presence of fluids by maintaining a water and salt concentration is known as osmoregulation

Question 17

Fill in the blanks:
If the water content of the blood is low, the brain produces ————— (more/less) ADH. This means a —————— (lower/higher) volume of water —————- (re-absorbed/diffused) by the kidney. This results in ——————- (dilute/concentrated) urine.

Answer 17

If the water content of the blood is low, the brain produces more ADH. This means a higher volume of water -re-absorbed by the kidney. This results in concentrated urine.

Question 18

Fill in the blanks:
If the water content of the blood is high, the brain produces ————— (more/less) ADH. This means a —————— (lower/higher) volume of water —————- (re-absorbed/diffused) by the kidney. This results in ——————- (dilute/concentrated) urine.

Answer 18

f the water content of the blood is high, the brain produces less ADH. This means a lower volume of water re-absorbed by the kidney. This results in dilute urine.

Question 19

When does kidney failure occur?

Answer 19

Occurs when kidneys do not function properly or sufficiently resulting in the accumulation of waste products and toxic materials.

Question 20

What is dialysis?

Answer 20

Dialysis is the process of removing excess water, solutes, and toxins from the blood in people whose kidneys can no longer perform these functions naturally.

Question 21

What is kidney transplant?

Answer 21

Kidney transplant or renal
transplant is the organ transplant
of a kidney into a patient with
end-stage kidney disease. There has to be a close tissue match otherwise the body will reject the kidney and destroy it

Question 22

Explain dialysis

Answer 22

Blood is removed from a vein in the arm, and is kept moving through dialysis tubing in the dialysis machine using a pump. The tubing is very long to provide a large surface area.

The dialysis fluid in the dialysis machine contains the same concentration and components of healthy blood ie. glucose, water, ions such as magneisum, sodium and pottasium. Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration to a region of lower concentration.

This means that excess glucose, water, salts and urea and uric acid which move to the dialysis fluid which has a lower concentration hence filtering the blood.

The cleaned blood is then passed through a bubble trap to remove any air bubbles, before being returned to the patient’s vein.

Question 23

ADV of kidney transplant-

Answer 23

• Permanent Solution
• Less frequent visits to the hospital

Question 24

D-ADV of kidney transplant

Answer 24

• Fear of rejection
• Restriction of diet
• Dependance on immunosuppressant drugs
• Some relegions do not allow transplant

Question 25

ADV of dialysis

Answer 25

• No fear of rejection
• Lesser restriction of diet

Question 26

D-ADV of dialysis

Answer 26

• Frequent hospital visits required
• Expensive procedure

Question 27

Define peristalsis?

Answer 27

Rhythmic contraction of smooth muscles in the ureter

Question 28

Define Homeostasis

Answer 28

Keeping the internal environment constant