Digestive System

Question 1

Type of nutrients

Answer 1

1. Carbohydrates
2. Lipid
3. Protein
4. Vitamin
5. Minerals
6. Water

Question 2

Carbohydrates

Answer 2

1g = 4kcal energy

Can add into
protein (glycoproteins)
Lipid (glycolipids)

Question 3

Types of carbohydrates

Answer 3

Monosaccharides ( glucose, fructose)
Simplest structure

Disaccharide (maltose, lactose)
Two monosaccharide linked together

Polysaccharide（starch/ glycogen)
More than 2 monosaccharide connect

Question 4

Non-digestible polysaccharide from plants = cellulose

Soluble vs insoluble

Answer 4

Soluble:
1. Bind intestinal fat to prevent over absorption
2, reduce body cholesterol
3. Stabilise blood glucose

Insoluble:
1. Add bulk to feces
2. Stimulate faeces movement

Question 5

Four types of lipid

Answer 5

1. Triglyceride ( fats)
   2nd choice of energy
   Keep warm
2. Phospholipid
   Structural component of cell membrane
3. Steroids
   Cholesterol in animal & plant
   Structural component of cell membrane
4. Saturated fat
   Carbon-carbon single bond
   Animal fat
   increased risk of cardiovascular diseases

Question 6

Lipid in blood

Density of lipoprotein

Answer 6

Is not soluble -) triglyceride circulate as lipoprotein

LDL-) transport cholesterol from liver to cell

HDL-) removing extra cholesterol, transporting cholesterol from lining to glands for hormone synthesis or bile excretion

Question 7

Proteins functions

Answer 7

Build block of body tissue
Enzyme
Receptor
Transport agent
Hormone
pH buffer
Energy source

Question 8

Vitamins- essentials vs non-essentials
Water soluble vs fat soluble

Answer 8

Essentials
A
B
C
E

Non-essentials
D
K

Water soluble: B & C
Cannot store in body, excrete by urine, quick deficiency

Fat soluble: A D E K

Question 9

Minerals sources, 7 major & minor

Answer 9

Source: beef, liver

Major minerals: calcium, potassium, magnesium, sodium, chloride

Trace mineral: copper, zinc, iron

Question 10

Water functions

Answer 10

As a transport medium
• As a solvent
• As a lubricant
• Regulate body temperature
• Help in digestion, absorption and excretion
• Help in maintaining the homeostasis of ion

Question 11

Metabolism-) anabolism & catabolism

Answer 11

Anabolism-) system to build up molecules

Catabolism-) system to break down molecules
-) slowly releasing energy

Question 12

Stage of digestion

Answer 12

1. Ingestion
2. Secretion
3. Mobility
4. Digestion
5. Absorption
6. Defaecation

Question 13

Parts of GI tract & Accessory digestive organs

Answer 13

Mouth
Pharynx
Oesophagus
Stomach
Small intestine
Large intestine

Teth
Tongue
Salivary glands
Liver
Galbladder
Pancrease

Question 14

Peritoneum & mesentery

Answer 14

Parietal wall-) outside, connect to abdominal wall
Visceral peritoneum-) cover organ

Mesentery-) double layer of visceral pitoneum

Question 15

Four layers of tissue in GI tract

Answer 15

1. Epithelial
   Most inner
   Goblet cell-) secrete mucus for protection and lubricate
2. Submucosa
   Connective tissue
3. Muscularis extrema
   Skeletal / smooth muscle
   Outer circular, inner longitudinal muscle
4. Serosa
   Outer: visceral pertoneum

Question 16

2 actions of gi tract

Peristalsis向前推

Segmentation前後前後撈
Small intestine ✅

Question 17

Mouth

Answer 17

For chewing food

Convert food into bolis

Carbohydrate digestion

Question 18

Teeth

Answer 18

Hild 20
Grown 32

Incision
Tear
Tear & crush
Grinning

Question 19

Salivary glands

Answer 19

Secrete saliva
1. Water to dissolve food
2. IgA antibody & lysozyme for bacteria killing

Question 20

Oesophagus

Answer 20

25cm

Skeletal muscle-) mix -) smooth muscle

Push food with peristalsis down to stomach

Question 21

Stomach

Answer 21

2L, mix & churn food
Mainly protein digestion, no absorption.

Question 22

Swallowing steps

Answer 22

1. Food bolus push by tongue from oral cavity to orolarynx
2. Initial reflex contraction of pharyngeal muscle to propel food into laryngopharynx
3. Soft platelet rise to block food from entering nasopharynx
4. Epiglottis prevent food entering airway
5. Relax upper oesopharyngeal sphincter
6. Food pass thru by peristalsis
7. Relax of lower oesophageal sphincter to allow food entering stomach

Question 23

Stomach 4 parts

Answer 23

Cardia ( near oesophagus)

Fundus

Body

Pylorus ( funnel shape, connect to dudenum

Question 24

4 layers of stomach

Answer 24

Mucosa

Submucosa

Muscularis externa

Gastric pit
1. Surface cell: form mucus layer muon top
2. Neck cell: secrete mucus to protect stomacch

Question 25

Small intestine

Answer 25

Duodenum( chemical digestion Jejunum (nutrient asorption Illeum (absorp nutrient & bile salt)

Question 26

Villi 絨毛 2 deviations

Answer 26

With capillaries-) absorb non-lipid substance With lacteal- )absorb lipid substance

Question 27

Type of digestive juice in intestine

Answer 27

1 Intestinal juice 2. Pancreatic juice 3. Bile

Question 28

Pancreas- location, component Pancreatic juice

Answer 28

Location: at epigastric & umbilical region posterior to stomach & liver Pancreatic acini Release pancreatic enzyme to duodenum to digest sugar, peptide, lipid Pancreatic islet Secrete Insulin & glucagon Component of pancreatic jucie 1 water with bicarbonate-) alkaline, neutralise acidic chyme 2. Pancreatic amylase 4. Protease 3. Pancreatic lipase

Question 29

Liver location, function

Answer 29

At hypochondriac & epigastric region Function 1. Production of cholesterol (vit D 2. Storage of micro nutrient (copper, zinc 3. Blood sugar balance 4. Produce of bile 5. Protein synthesis( globulin 6. Immune system 7. Metabolism 8. Detoxification

Question 30

Liver function ( shorter)

Answer 30

1. Site for metabolism 2. Bile synthesis 3. Storage of nutrient 4. Activate vit D to calcitriol

Question 31

Gallbladdar 膽囊

Answer 31

Store up to 50 mL bile

Question 32

Bile & related

Answer 32

Bile contain water, bile salt & bilirubin Bile salt: emulsify fat into droplet Bilirubin: form after rbc breakdown

Question 33

Mechanical digestion in small intestine

Answer 33

Step 1. Initiate with chyme entering 2. Regular contraction / relaxation of circular muscle 3. Mix chyme with digestive juivce 4. Slow down chyme movement to facilitate nutrition absorption

Question 34

Large intestine 1234, characteristics

Answer 34

1. Caecum 盲腸 2. Ascending colon 3. Transverse colon 4. Descending colon Lack of villi Lot of goblet cell for faeces easy passing Motility stimulated by 1. Arrival of food in stomach 2. Filling of large intestine

Question 35

Colonial bacteria

Answer 35

Immune defence, prevent pathogen growing Produce gases Breakdown indigestible fibre & protein by fermentation (發酵） Metabolize bilirubin colour to form shit colour

Question 36

Defaecation muscle, flow

Answer 36

Internal involuntary smooth muscle External spincter Flow 1. Faeces arrive rectum 2. Increase pressure of rectum 3. Trigger relax of internal sphincter muscle 4. Contraction of rectal wall to propel faeces to external anal sphincter 5. Voluntary control contract the abdominal muscle & relaxation of external anal sphincter to daefecate

Question 38

Cephalic phase digestion response

Answer 38

Purpose: prepare digestion 1. Transmit through facial nerve to secrete salivary secretion 2. Thru vagus nerve to 2.1 stimulate muscle of stomach 2.2 stimulate secretion of parietal cells & pepsinogen in the stomach 2.3 stimulate to secrete gastrin

Question 39

Gastric phase digestion response

Answer 39

Purpose: increase efficiency of stomach digestion 1. induce gastrin secreted by g cell 1.1 intensify contraction of g cell 1.2 increase secretion of hydrochloric acid by parietal cell 1.3 increase secretion of mucous by mucous neck cell

Question 40

Intestinal phase digestion response

Answer 40

Purpose: 1. Enhance efficiency 2. Prevent further uptake of food 3. Provide time for digestion Response Stimulate chlocytokinin, secretin, gastric inhibitory peptide CCK: stimulate gallbladder contraction Secretin: reduce secrete if gastric acid GIP: stimulate insulin release