Digestive System

Question 1

The Four Layers of GIT Tact

Answer 1

• Mucosa (inner most layer)
• Submucosa
• Muscularis Externa/Propria
• Adventia/Serosa (outermost layer)

Question 2

Muscosa:

Answer 2

• Mucus secretion to lubricate food we have eaten
• Nutrient absorption
• Pathogen defense
• Muscularis mucosa: thin muscle layer. Has villi to increase SA to helps movement and helps likeliness of absorption to occur
• Gastric pits: secrete several things such as mucus, enzymes, acids etc.

Question 3

Submucosa:

Answer 3

• Loose connective tissue
• Larger blood vessels
• Lymphatic vessels
• Nerves that enter and exit the submucosa

Question 4

Muscularis Externa/Propria

Answer 4

• Segmentation & peristalsis
• Two muscular layers: aid with segmentation & peristalsis
  
  • circular muscle
  • longitudinal muscle

Question 5

Adventia/Serosa (outermost layer)

Answer 5

visceral peritoneum

Question 6

List digestive Processes:

Answer 6

Cephalic Phase
Ingestion
Propulsion
   Swallowing
   Peristalsis
   Segmentation
Mechanical/Physical digestion
Chemical digestion
Absorption
Defecation

Question 7

Cephalic Phase:

Answer 7

digestion begins in brain, preps the body to begin the process of digesting food

Question 8

Peristalsis:

Answer 8

rhythmic contraction & relaxation of different parts of the digestive tract which allows for the movement of food throughout the digestive tract.

Question 9

Segmentation:

Answer 9

food moves backwards and forwards to increase rate of nutrient absorption

Question 10

Mechanical/Physical Digetsion

Answer 10

there is no change to the chemistry of the food. It breaks up the food into smaller bits which then facilitates enzymes to act further -> more surface area available o enzymes to act on food

Question 11

Chemical Digestion

Answer 11

enzymes chemically breakdown food

Question 12

Absorption

Answer 12

nutrients are available to be absorbed. Absorption beings in the small intestine where most absorption occurs

Question 13

Defecation:

Answer 13

removal of waste. Large intestine.

Question 14

What enzymes break down Carbohydrates?

Answer 14

Salivary Amylase
Pancreatic Amylase
Maltase

Question 15

What emzyme breaks down protein?

Answer 15

Pepsin, Trypsin & Peptidases

Question 16

What enzymes breakdown Nuclei acids

Answer 16

nuclease & nucleosidase

Question 17

what enzyme breaks down fats

Answer 17

lipase

Question 18

Major Functions of Colon:

Answer 18

• Absorption of water
• Absorption of electrolytes
• Absorption of metabolites/vitamins produced by bacteria
• Store and eliminate indigestible food residues – defecation

Question 19

Accessory Organs:

Answer 19

Liver
Pancreas
Gallbladder

Question 20

The Liver - Accessory Organ

Answer 20

structural unit: lobules
brick life pattern of hepocytes
radiate from central nerve

Question 21

Kupffer Cells (in the liver)

Answer 21

a phagocytic cell which forms the lining of the sinusoids of the liver and is involved in the breakdown of red blood cells & phagocytose bacteria & debris

Question 22

Bile (from liver)

Answer 22

• alkaline solution

- aids in digestion (phospholipids & bile salts)

Question 23

Gallbladder - Accessory Organ

Answer 23

• storage organ for bile & concentration of bile

Question 24

Functions of the Liver and Gallbladder:

Answer 24

• Carbohydrate, lipid, and protein metabolism
• Processing of drugs and hormones
• Bilirubin excretion
• Bile salt synthesis
• Storage
• Phagocytosis
• Vitamin D activation

Question 25

Pancreas – accessory organ:

Answer 25

- Is a gland that lies posterior to the stomach - Produces enzymes that digest carbohydrates, proteins, fats, and nucleic acids - Produces sodium bicarbonate which buffers stomach acid - Empties its contents into the duodenum

Question 26

phases of digestion

Answer 26

Cephalic phase: stimulates gastric secretion & motility Gastric phase: neural & hormonal mechanisms Intestinal phase: neural & hormonal mechanisms

Question 27

Mouth - functions:

Answer 27

``` Ingestion of food Mechanical digestion Chemical digestion Moistens and lubricates food Some antimicrobial activity ```

Question 28

Pharynx - functions:

Answer 28

Propulsion of food Oral cavity -> esophagus Lubrication

Question 29

Esophagus - function:

Answer 29

Propulsion of food esophagus -> stomach Lubrication

Question 30

Stomach - function:

Answer 30

Mechanical digestion Chemical digestion Antimicrobial function

Question 31

Small Intestine - function:

Answer 31

Absorbs breakdown products of carbohydrates, proteins, lipids, and nucleic acids, along with vitamins, minerals, and water Performs mechanical digestion via segmentation

Question 32

Large Intestine - function:

Answer 32

Absorbs most residual water, electrolytes, and vitamins, produces by enteric bacteria Propulsion and elimination of faeces Rectum -> external environment. Faecal matter concentration & temporarily storage Mucus secretion for ease of faecal matter passage