Large intestine

Question 1

Purpose of the digestive system

Answer 1

supply us with the nutrients we need

Question 2

Roles of the digestive system

Answer 2

Digestion (large particles broken down), Absorption (molecules move from lumen of digestive system to blood vessels), Elimination (substances that aren’t absorbed are removed)

Question 3

Parts of the colon

Answer 3

Ascending, transverse, descending

Question 4

Functions of the large intestine

Answer 4

Further absorption of water and some salts and vitamins made by gut bacteria, Bacterial activity- digests cellulose (in plants) and synthesises vitamins

Question 5

Large intestine (4)

Answer 5

1.5 meters long, doesn’t contain villi, secretes mucous, water absorption occurs making the contents more solid

Question 6

Faeces

Answer 6

Semi-solid material in the large intestine after water absorption and bacterial action are complete

Question 7

What is faeces made up of?

Answer 7

Undigested food material (usually cellulose- source of fibre), bacteria, bile pigments, discarded lining cells, water

Question 8

Defecation

Answer 8

Not excretion, elimination of undigested wastes from the large intestine

Question 9

Excretion

Answer 9

Removal of wastes PRODUCED by the body’s cells

Question 10

Cellulose

Answer 10

fibre, insoluble polysaccharide (carbohydrate), humans lack the enzyme to break it down, ingested cellulose eliminated,

Question 11

When cellulose moves through the digestive tract

Answer 11

it stretches the smooth muscle walls, smooth muscles reflexively contract and move material along the intestine meaning cellulose stimulates regular peristalsis

Question 12

Diets low in cellulose

Answer 12

cause intestinal content to move slower through the digestive tract, longer time in the large intestine means the contents become drier meaning it is more difficult to move through the intestinal tract

Question 13

Constipation

Answer 13

irregular defecation, contributed to by lack of fibre and water in the diet, increased fibre and water in the diet prevents/cures constipation

Question 14

What can constipation lead to?

Answer 14

Haemorrhoids

Question 15

How do haemorrhoids form?

Answer 15

Straining which causes the protrusion or rupture of blood vessels in the rectum of anus, the damaged vessels are called haemorrhoids

Question 16

Diarrhoea

Answer 16

Frequent elimination of watery faeces

Question 17

What is diarrhoea caused by?

Answer 17

Foods, bacteria or viruses, rate of peristalsis increases meaning there is inadequate time for water reabsorption

Question 18

Bowel cancer

Answer 18

More common in countries where diets contain less fruit and vegetables, if a large section of bowel is removed a colostomy provides an alternate elimination route

Question 19

Cardio-vascular disease

Answer 19

Predisposed by obesity, the heart has to work harder in an obese body straining it and causing damage, obesity can also cause high blood pressure (hypertension)

Question 20

Atherosclerosis

Answer 20

Can result from a high-fat diet, results in heart attacks or strokes

Question 21

Type 2 diabetes

Answer 21

Predisposed by obesity, pancreas secretes insulin but the body does not respond to it resulting in high blood glucose levels, Long term diabetes can lead to kidney failure and blindness

Question 22

Osteo-arthritis

Answer 22

Obesity places more pressure on all of the body’s joints meaning the become damaged and worn

Question 23

Cancers

Answer 23

Around 15 types predisposed by obesity including bowel and breast cancers