Digestive system

Question 1

Digestion

Answer 1

Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the blood stream

Question 2

Mechanical digestion

Answer 2

the physical breakdown of food particles into smaller pieces to increase the surface area.

Question 3

Chemical digestion

Answer 3

Chemical digestion uses enzymes to break down large, complex molecules into smaller, simpler molecules. These smaller molecules are then small enough to be absorbed into the bloodstream.

Question 4

4 Functions of digestion

Answer 4

Ingestion of food and water, Movement of food along Alimentary Canal (GI Tract), Absorption of digested food and water into blood and lymph, Elimination of material that’s not absorbed

Question 5

Alimentary canal

Answer 5

the continuous tube that runs from the mouth to the anus. the lining of the canal is the surface through which nutrients are absorbed.

Question 6

Mouth cavity

Answer 6

mechanical digestion by teeth, chemical digestion of starch by saliva

Question 7

Salivary glands

Answer 7

three pairs of glands produce saliva, which dissolves food so it can be tasted. saliva contains mucus that lubricates the mouth and food and holds food in a bolus for swallowing. it also contains the enzyme salivary amylase, which begins starch digestion.

Question 8

Liver

Answer 8

produces bile, which is stored and concentrated in the gall bladder

Question 9

Gall bladder

Answer 9

stores bile and releases it into the small intestine, where the Bile salts act as emulsifying agents, breaking fat down into smaller droplets.

Question 10

Duodenum

Answer 10

first part of small intestine, The absorption of vitamins, minerals, and other nutrients

Question 11

large intestine

Answer 11

transverse, ascending, descending colon - Glandular cells in L intestine secrete mucus, the slow movement of materials allows water to be absorbed and contents to harden, Bacteria breaks down the remaining organic materials, which are then absorbed through the walls into the blood.

Question 12

Caecum

Answer 12

pouch where the small intestine joins the large intestine

Question 13

Appendix

Answer 13

plays a role in immunity and stores useful bacteria

Question 14

Rectum

Answer 14

final part of large intestine in which feces are formed

Question 15

Pharynx

Answer 15

back of mouth cavity, by moving upwards and backwards, the tongue pushes food into the pharynx for swallowing

Question 16

Oesophagus

Answer 16

carries food from the mouth stomach, it passes through the diaphragm into the abdominal canal

Question 17

Pyloric sphincter

Answer 17

band of circular muscle that regulates flow of material from the stomach to duodenum

Question 18

Pancreas

Answer 18

produces pancreatic juice containing enzymes for digesting proteins, lipids and nucleic acids

Question 19

Small intestines

Answer 19

its lining secretes intestinal juices contains enzymes, internal surface is lined with villi for the absorption of digested food.

Made up of:
1. Duodenum
2. Jejunum
2. Ileum

Question 20

Anus and rectum

Answer 20

a muscle that can be voluntarily controlled, Peristalsis pushes left over material in L Intestine into Rectum, Walls of rectum stretch + trigger defecation, Controlled by anal sphincters.

Question 21

Human Dentition

Answer 21

Mechanical Mastication (Chewing action of teeth)-
4 incisors: chisel shaped teeth for biting, cutting
2 canines: 1 on each side for tearing
4 premolars: 2 on each side
6 molars: 3 on each side, crushing + grinding food

Question 22

Saliva (chemical)

Answer 22

Saliva secreted by salivary glands –mucus, digestive, enzymes, salivary amylase

Functions- Mucus lubricates mouth and food, Dissolves food so taste receptors are stimulated, Stickiness of mucus helps food hold together – bolus, Salivary amylase breaks down starch into glucose

Question 23

Bolus Formation + Swallowing

Answer 23

Bolus is the term for food after it has been ingested, chewed and mixed with saliva in one’s mouth. The function of bolus is toprovide a more compact package of food that can be better swallowed.

Question 24

Swallowing

Answer 24

Tongue pushes bolus down pharynx into oesophagus.
Epiglottis closes off trachea when swallowing.

Question 25

Peristalsis

Answer 25

the involuntary constriction and relaxation of the muscle, creating wave-like movements that push the contents of the canal forward.

Question 26

stomach (Mechanical Digestion)

Answer 26

Muscular contractions churn food and mixes with gastric Juice, converted to thick soupy liquid called Chyme, produces pepsin and rennin.

J shaped bag with mucosa folds in stomach called Rugae, Lined with a mucosa layer- Gastric Pit

Question 27

Cardiac Sphincter

Answer 27

separates the oesophagus and stomach

Question 28

Pepsin

Answer 28

type of protease, a stomach enzyme that serves to digest proteins found in ingested food, only works in acidic condition. eg amino acids and hydrophobic

Question 29

Gastric Pit

Answer 29

contains cells, which secretes HCl (which kills bacteria
and help with food breakdown), mucus and gastric juices- moves from almost natural acidic organ to a high acidic organ.

Question 30

Pyloric Sphincter

Answer 30

regulates the chyme entering into the Small intestine.

Question 31

Segmentation

Answer 31

is to slosh the contents of the small intestine back and forth mixing its contents with the digestive juices.

Question 32

Feaces

Answer 32

Feces contains water, undigested food material + remains of cells that have broken away from alimentary canal.

Elimination – Removal of indigestible material, bacteria and bile pigments from the body.

Question 33

Constipation

Answer 33

If large Intestine movement slows and contents stay there for a while, leads to constipation. if too much water is absorbed, feces becomes harder drier, defecation becomes difficult + painful.

Question 34

Diarrhea

Answer 34

Frequent watery feces due to irritation of S or L Intestine. Which increases peristalsis + material moves through too quick + water not absorbed - Bacterial/Viral infection. Ie food poisoning; Cholera can lead to severe diarrhea, dehydration then death.

Question 35

Soluble fiber in the diet

Answer 35

Soluble fiber attracts water in the gut, slow digestion, prevent blood glucose surges after eating and reduce hunger. uncontrol of blood glucose = risk factors for diabetes, doubles the risk of developing heart disease.

Question 36

Bowel cancer

Answer 36

Uncontrolled growth of cells in the wall of the large intestine. Research suggests L intestine cancer due to diet, high alcohol intake and smoking, Overweight and physical inactivity

Question 37

Coeliac disease

Answer 37

Unable to tolerate a protein called gluten – If eat gluten, immune system destroys villi in small Intestine. villi absorption doesn’t happen therefore become malnourished no matter how much food is eaten.

Muscle cramps, joint pain, can be difficult to diagnose, Treatment: Gluten Free Diet.

Question 38

Protease

Answer 38

an enzyme that spits or severs proteins, acts under any condition.

Question 39

Mouth

Answer 39

salivary gland, neutral-slightly acidic, produces salivary amalyse, acts upon glycogen and starch, produces maltose.