Exchange of Nutrients and Wastes

Question 1

Oral cavity

Answer 1

Amylase breaks down the food. Teeth grind food down to increase surface area for digestion

Question 2

Oesophagus

Answer 2

Muscles contract, peristalis pushes food down into the stomach

Question 3

Stomach

Answer 3

Mixed with gastric acid. Muscles churn the food to mix it with digestive enzymes.

Question 4

Small intestine

Answer 4

Main site for absorption of food. Has three regions- duodenum, jejunum, and ileum.

Question 5

Large intestine

Answer 5

Removes water from undigested food. Has four main regions- ascending colon, transverse colon, descending colon and bowel. They work together to complete digestion.

Question 6

Rectal cavity

Answer 6

Acts as a temporary storage site for waste.

Question 7

Mechanical digestion

Answer 7

food is physically broken down into smaller pieces.

Question 8

Villi

Answer 8

The inner surface of the ileum has folds called villi they help slow down the passage of food and increase SA for digestion

Question 9

Chemical digestion

Answer 9

is when the complex molecules in food are broken into simpler molecules. This is done using enzymes or acid.
Amylase: breaks down carbohydrates
Protease: break down of proteins
Lipase: breakdown of lipids.

Question 10

Different nitregenous wastes produced by breakdown of proteins.

Answer 10

Ammonia- the direct waste produced as a byproduct of protein metabolism.
Urea- formed in the liver from the conversion of ammonia.
Uric acid- in reptiles and birds this is formed in the liver from the conversion of ammonia.

Question 11

Excretory system

Answer 11

includes a pair of kidneys that removes excretory products from the blood plasma.

Question 12

Kidney

Answer 12

Kidney is bean shaped. Enclosed by a capsule of connective tissue and composed of two layers of tissue.

Question 13

Nephron

Answer 13

the functional unit of the kidney. Each kidney contains between one and two million nephrons embedded in loose connective tissue and richly supplied with blood. Each nephron has an elongated tubule associated at one end with a group of blood capillaries via a cup- shaped Bowman’s capsule and opening at the other end into a collecting duct.

Question 14

glomerulus

Answer 14

filter plasma to produce a glomerular filtrate.

Question 15

Bowmans capsule

Answer 15

generates urine in the process of removing waste and excess substances from the blood

Question 16

Proximal tubules

Answer 16

reabsorption of filtrate in accordance with the needs of homeostasis

Question 17

loop of henle

Answer 17

the recovery of water and sodium chloride from urine

Question 18

collecting tubule

Answer 18

regulation of water, electrolyte and hydrogen ion balance

Question 19

distal tubules

Answer 19

regulation of water, electrolyte, and hydrogen ion balance

Question 20

excretory system

Answer 20

gets rid of wastes. defecation is passing faeces from the digestive tract to the GI tract. Seperate to excretion. Organs involved are skin, lungs, liver and kidney.

Question 21

How does the body produce waste?

Answer 21

cellular metabolism.

Question 22

cellular respiration produces..

Answer 22

carbon dioxide which isnt needed so is excreted by the lungs.

Question 23

kidney

Answer 23

main excretory organ

Question 24

liver

Answer 24

converts things into forms we can excrete

Question 25

skin

Answer 25

organ for excess heat, salts and some urea. excretes waste through sweating

Question 26

glomerular filtration

Answer 26

Blood enters the glomerulus under high pressure. Water, ions and small molecules such as glucose, amino acids and urea are forced through the capillary wall and lining of the Bowman’s capsule into the capsular space by ultrafiltration. The filtrate has a composition similar to plasma, but without the larger protein molecules. Blood cells normally do not leave the blood vessel.

Question 27

reabsorption

Answer 27

As the filtrate leaves Bowman’s capsule it passes into the proximal convoluted tubule where many of the useful constituents are reabsorbed into the surrounding capillary network. The cells lining the proximal convoluted tubule actively absorb glucose and amino acids.