Digestive system

Question 1

Roles of the digestion system

Answer 1

digestion: large molecules broken into smaller pieces
absorption: required molecules enter the blood stream
elimination: removal of unabsorbed materials

Question 2

saliva

Answer 2

lubricates, dissolves, creates bolus, washes teeth, neutralises acid, antibodies destroy bacteria, chemically digests carbs

Question 3

types of teeth

Answer 3

incisors - biting, cutting
canines - tearing, piercing, shearing
premolars - crushing, grinding
molars - crushing and grinding
dental formula: 2123

Question 4

alimentary canal structure

Answer 4

mucosa, sub mucosa, muscle layer, serosa

Question 5

oesophagus

Answer 5

has a double layer of circular muscle in the walls and longitudinal muscle along the length of the canal - causes peristalsis

Question 6

peristalsis

Answer 6

wave-like contractions that moves the bolus into the stomach

Question 7

stomach

Answer 7

chemically digests proteins (pepsin from gastric juice), mechanically digests (churning, amalgamation from bile)
drugs, alcohol and water are absorbed
turns to chyme after 4-6 hours

Question 8

Protein digestion within the stomach

Answer 8

inactive pepsinogen contained in gastric juice, activated by hydrochloric acid so as to prevent glands being destroyed - pepsin (active) breaks down protein into polypeptides

Question 9

small intestine structure

Answer 9

duodenum - connects to stomach
jejunum - middle section
Ileum - attaches to the colon

Question 10

Villi

Answer 10

increase the surface area so the rate of absorption is rapid

Question 11

Villi structure

Answer 11

consists of a single capillary and lacteal
glycerol and fatty acids enter the lacteal
amino acids and sugars enter the capillary

Question 12

pancreas

Answer 12

connected to the small intestine via the pancreatic and common bile duct
secretes pancreatic juice (slightly basic); contains protease, lipase and amylase

Question 13

bile

Answer 13

secreted by liver ad stored in gall bladder

contains no digestive enzymes, but amalgamates fats

Question 14

large intestine

Answer 14

secretes mucous and absorbs water

Question 15

faeces

Answer 15

semi solid material in the large intestine after water absorption; made up cellulose, bacteria, bile pigments,

Question 16

types of digestion

Answer 16

mechanical digestion: stomach (churning, bile), mouth (chewing)
chemical digestion: enzymes in mouth, stomach, and small intestion