Excretory

Question 1

What is excretion

Answer 1

It is the removal of metabolic and nitrogeous waste from the body to maintain homeostasis in the body.

Question 2

What is excretory system?

Answer 2

The organs that are involved in the formation, storage and elimination of urine constitute the Excretory system.

Question 3

Give reason

Excretion is an important metabolic process

Answer 3

It is important as it removes urea (nitrogenous waste) which if allowed to accumulate in the blood, can be fatal.

Question 4

State 5 harmful wastes which are removed from the body

Answer 4

1. Carbon dioxide and water vapour
2. Nitrogenous metabolic waste
3. Excess salts and vitamins
4. Excess water
5. Bile pigments

Question 5

How is carbon dioxide and water formed in our body? How is it removed

Answer 5

The cells in our body liberate energy by oxidising glucose which produces CO₂ and water.
CO₂ is expelled by lungs while excess water is expelled by sweat

Question 6

State the nitrogenous wastes which are expelled from the body

Answer 6

Urea, Creatinine, Uric acid, Ammonia.

Question 7

How is Urea formed?

Answer 7

After digestion, extra amino acids in the body cannot be stored. Hence the liver breaks the amino acid into usable glucose and urea which needs to be excreted out

Question 8

What type of salts and vitamins are excreted

Answer 8

Excess common salt (NaCl) and water-soluble vitamins like B&C are eliminated

Question 9

How does water help in excretion process

Answer 9

Water is useful in dissolving the harmful substances to carry them out

Question 10

which bile pigment is removed from the body and how?

Answer 10

yellow bilirubin is excreted with faeces and in urine
these pigments are modified in the intestine to give faeces their brown-ish yellow colour

Question 11

Write the 4 organs which help in excretion of substances from body

Answer 11

• Kidneys: they are the primary excretory organs which remove nitrogenous wastes like urea from the blood
• Skin: Sweat excretes water, NaCl and small amounts of urea
• Lungs: They excrete CO2 from our body through the expired air
• Liver: detoxifies ammonia by converting it to urea

Question 12

Define Homeostasis and Osmoregulation

Answer 12

• Homeostasis refers to the processes which maintain a healthy internal state
• Osmoregulation is the process of maintaining salt-water balance in the body by the kidney

Question 13

What is the location of kidneys?

Answer 13

Kidneys are 2 bean-shaped organs located on either side of the backbone and are protected by the last 2 ribs

Question 14

Give reason

The right kidney is at a slightly lower level than the left

Answer 14

To accomodate the liver

Question 15

State location and function of Ureter

Answer 15

• Ureter arises from the Hilum of each kidney and joins the urinary bladder
• Carries urine from the kidney to the urinary bladder

Expanded part of ureter into the kidney is called renal pelvis

Question 16

State location of Hilum

Answer 16

Hilum is present in the median surface of each kidney

Question 17

State location and function of Urinary bladder

Answer 17

• It is located in the lower abdomen
• It stores urine temporarily

Question 18

State location and function of urethra

Answer 18

• It arises from the urinary bladder to the outside of the body
• carries urine from urinary bladder to the outside of the body

Question 19

State the function and location of Sphincter

Answer 19

• Gaurds the opening of urinary bladder into the urethra
• it relaxes to allow micturition

Question 20

What is micturition

Answer 20

Micturition is the process of removal of urine from the urinary bladder to the outside of the body through the urethra under the impulse of the nervous system

Question 21

What are uriniferous tubules

Answer 21

structural functional unit of kidneys

Question 22

What is malpighian capsule?

Answer 22

the glomerulus and bowman’s capsule is together known as malpighian/renal capsule

Question 23

why does cortex have dotted appearance?

Answer 23

because of the bowman’s capsule and pct which makes it dotted

Question 24

what and where is Glomerulus

Answer 24

it is a knot like mass of blood capillaries fitted closely inside bowman’s capsule

Question 25

Where is loop of henle

Answer 25

It is part of the nephron before the pct in the medulla of kidney

Question 26

Where is pct and dct

Answer 26

both lie in the cortex
pct connects bowman’s capsule to loop of henle
dct connects loop of henle to collecting duct

Question 27

Why does medulla have stripped appearance

Answer 27

it has stripped appearance due to loop of henle ad collecting duct

Question 28

What is vasa recta

Answer 28

it is the secondary capillary network which arises from the efferent arteriole

Question 29

What is ultrafiltration

Answer 29

It is the process of filtration of water, salt, urea, amino acids, glucose from the blood in the glomerulus to the bowman’s capsule due to high hydrostatic pressure caused due to difference in diameter of the afferent and efferent arteriole.