digestive system

Question 1

layers of GI tract

Answer 1

oesophagus to anal canal
1) serosa/adventitia
2) muscularis
3) submucosa
4) mucosa

Question 2

the oral cavity’s accessory organs

Answer 2

teeth
tongue
salivary glands

Question 3

salivary glands’s pairs

Answer 3

1) parotid
2) submandibular
3) sublingual

Question 4

function of salivary glands

Answer 4

produces saliva –>
digestion
lubrication
protection of oral cavity

Question 5

parotid

Answer 5

one of the pairs of the salivary glands
- largest, right in front the ears
- makes a watery saliva
–> containing salivary amylase (breaks down starchy stuff)

Question 6

submandibular

Answer 6

one of the pairs of the salivary glands
-located under the jaw, under the lower teeth
—> produces a serous (watery) saliva and mucous saliva
–> makes up most of the saliva

Question 7

sublingual glands

Answer 7

one of the pairs of the salivary glands
the smallest one
- found directly under the jaw, under the tongue
–> produces mucous saliva
lubricate the oral cavity and faciliates the swallowing

Question 8

pharynx struc and func

Answer 8

struc : skeletal muscle
func : moves bolus to oesphogaus

Question 9

oesophagus struc and func

Answer 9

struc : muscular tube
func : bolus to stomach
–> upper = sketeal
middle = mixed
lower = smooth

Question 10

anatomy of the stomach

Answer 10

J shaped chamber,
4 main regions, cardia, fundus, body, pylorus
Rugae
Muscular vales (sphincter)

Question 11

function of the stomach

Answer 11

holding reservoir
Mixing chamber = turns bolus into chyme
secretion of gastrin
secretion of gastric juice (HCl)

Question 12

rugae

Answer 12

when stomach is empty, the rugae are folds that can stretch to increase volume of stomach
When the stomach is full, the rugae are flattened out - increase SA
(also acts a protective barrier from the underlying tissue to prevent harming the stomach)

Question 13

Cardia

Answer 13

contains a cardiac sphincter to regulate the entry of food in the stomach

–> prevents food, stomach acid and digestive enzymes to go back up the oesophagus

Question 14

Fundus

Answer 14

collects digestive gases, stores the food and releases it back slowly

–> Stores the food to regulate the rate of digestion and prevents the small intestine from having to digest a lot of food at a time

Question 15

Body

Answer 15

releases pepsinogen and HCl, gastric juices == forms chyme

Pelsinogen is the inactive form of pepsin and is present in gastric juice: reacts with HCl to convert to pepsin
It’s made inactive and activated only in digestion so it doesn’t harm the cells that produce it

Question 16

Pylorus

Answer 16

contains the pyloric sphincter and regulates the exit of chyme, connects to small intestine

Question 17

mechanism of gastrin

Answer 17

gastrin(hormone) is released, binds to receptors on the parietal cells on the stomach

Triggers a series of signalling events involving enzumes and messengers on the stomach
stimulates H+/K+ ATPase which causes H+ to leave the cells, and be pumped into the stomach lumen, and H+ combines with Cl- to form HCL = gastric acid

Question 18

small intestine anatomy

Answer 18

duodenum, jejunum and ileum
joins with the large intestine at the ileocecal sphincter
lined with villi + microvilli

Question 19

small intestine function

Answer 19

receives pancreatic juice (via pancreatic duct) and bile (via common bile duct)
secretes intestinal juice
major site of digestion and absorption

Question 20

lumen of small intestine

Answer 20

covered with villi with microvilli to increase SA of absorption back into the blood

Question 21

duodenum

Answer 21

connects after the phylorus and recieves the digestive enzymes from the pancreas and bile from the liver = common bile duct
–> bile aid in the digestion/absorption of fats

Question 22

Jejunum

Answer 22

complete digestion and absoprtion of nutrients, vitamins, BIG 3 (carbs, fats, proteins)
= broken down into smaller pieces, absorbed into blood stream through the jejunum wall

Question 23

Ileum

Answer 23

complete absorption of nutrients, especially vitamin B12 and bile salts PLUS transport undigested materials and waste product from small –> large intestine for excretion

Question 24

intestinal juice

Answer 24

lowers pH of the acidic chyme!

Question 25

large intestine structure

Answer 25

caecum, colon, rectum and anal canal (anus)
internal (involuntary)/external anal sphincter (voluntary)

Question 26

colon 4 regions

Answer 26

ascending, transverse, descending, sigmoid

Question 27

large intestine function

Answer 27

absorption (water + electrolytes)
formation of faeces/excretion
some nutrients formed oooooo

Question 28

nutrients in the gut

Answer 28

bacteria can ferment and breakdown undigested food to produce nutrients that can be absorbed by the body