digestive system

Question 1

What is the primary function of the digestive system?

Answer 1

To bring essential nutrients into the internal environment for each cell of the body.

Question 2

List the three main processes of the digestive system.

Answer 2

• Ingestion
• Digestion
• Absorption
• Defecation

Question 3

What are the two main groups of organs in the digestive system?

Answer 3

• Alimentary canal / gastrointestinal (GI) tract
• Accessory digestive organs

Question 4

Name the organs of the GI tract.

Answer 4

• Mouth
• Pharynx
• Oesophagus
• Stomach
• Small intestine
• Large intestine
• Anus

Question 5

Identify the accessory digestive organs.

Answer 5

• Salivary glands
• Teeth
• Pancreas
• Liver
• Gall bladder

Question 6

What is mechanical digestion?

Answer 6

Mixing of food in the mouth by the tongue, churning of food in the stomach, and segmentation in the small intestine.

Question 7

What is chemical digestion?

Answer 7

Large molecules such as carbohydrates, lipids, and proteins are broken down into smaller absorbable molecules.

Question 8

Define defecation.

Answer 8

Elimination of indigestible substances, dead cells, and bacteria as faeces.

Question 9

What is the innermost layer of the GI tract called?

Answer 9

Mucosa.

Question 10

What does the lamina propria contain?

Answer 10

• Areolar connective tissue
• Blood and lymphatic vessels
• Immune cells
• Mucosa-associated lymphoid tissue (MALT)

Question 11

What type of epithelium is found in the oral cavity?

Answer 11

Stratified squamous epithelium, partially keratinized.

Question 12

What are gastric pits?

Answer 12

Depressions in gastric epithelium that lead into gastric glands.

Question 13

What is the function of parietal cells in the stomach?

Answer 13

Produce hydrochloric acid that activates pepsin and intrinsic factor needed for vitamin B12 absorption.

Question 14

What is the role of chief cells in the stomach?

Answer 14

Produce inactive protein-digesting enzymes called pepsinogens and gastric lipase.

Question 15

What are the functions of saliva?

Answer 15

• Lubricates and cleanses the mouth
• Moistens food to form a food bolus
• Begins breakdown of starch to maltose
• Buffers acidic foods
• Dissolves chemicals in food for taste

Question 16

What triggers increased salivation?

Answer 16

Entry of food into the mouth, as well as the sight and smell of food.

Question 17

What is the function of the pharynx?

Answer 17

Serves as a passageway for air and food.

Question 18

What is the oesophagus primarily composed of?

Answer 18

Striated muscle (first 2/3) and smooth muscle (last 1/3).

Question 19

What does peristalsis refer to?

Answer 19

The involuntary muscle contractions that move food through the digestive tract.

Question 20

What is the role of the enteric nervous system?

Answer 20

Regulates gastrointestinal motility and local conditions such as secretion and absorption.

Question 21

What are the two types of muscle in the muscularis of the GI tract?

Answer 21

• Inner circular layer
• Outer longitudinal layer

Question 22

What is the main function of the stomach?

Answer 22

Acts as a storage organ for food and secretes gastric juice.

Question 23

What is the significance of intrinsic factor produced by the stomach?

Answer 23

Necessary for the absorption of vitamin B12.

Question 24

What are the components of gastric juice?

Answer 24

• Hydrochloric acid
• Pepsin
• Intrinsic factor
• Gastric lipase

Question 25

Fill in the blank: The _______ is a muscular tube connecting the laryngopharynx and stomach.

Answer 25

oesophagus

Question 26

True or False: The stomach has a simple-columnar epithelium.

Answer 26

True

Question 27

What are the three major salivary glands?

Answer 27

* Parotid glands * Submandibular glands * Sublingual glands

Question 28

What do the muscularis mucosae in the mucosa layer consist of?

Answer 28

A thin layer of smooth muscle fibres.

Question 29

What is the main role of the submucosal plexus?

Answer 29

Regulating local conditions such as secretion, absorption, and blood flow within the gut.

Question 30

What is Pepsinogen converted into in the presence of HCl?

Answer 30

Pepsin ## Footnote Pepsinogen is an inactive precursor of pepsin, activated by hydrochloric acid.

Question 31

What enzyme cleaves triacylglycerols found in the fat of milk?

Answer 31

Gastric Lipase ## Footnote Gastric lipase's action is limited in adults and has an optimum pH of 5-6.

Question 32

What is the function of Rennin in infants?

Answer 32

Turns casein in milk into curd ## Footnote This action slows the progression of milk into the intestine.

Question 33

What stimulates the production of Pepsinogen?

Answer 33

Gastrin ## Footnote Gastrin is produced by G cells in response to various stimuli.

Question 34

What do Peptic (Chief) Cells secrete?

Answer 34

HCl and intrinsic factor ## Footnote Intrinsic factor is necessary for the absorption of vitamin B12.

Question 35

What enhances the effects of gastrin and acetylcholine in driving HCl secretion?

Answer 35

Histamine

Question 36

What hormone is released by G cells?

Answer 36

Gastrin ## Footnote G cells are enteroendocrine cells that respond to stomach distension and other factors.

Question 37

Which phase of gastric digestion is triggered by the sight, smell, or taste of food?

Answer 37

Cephalic Phase

Question 38

What reflex occurs when food reaches the duodenum?

Answer 38

Enterogastric reflex ## Footnote This reflex inhibits gastric motility and decreases gastric emptying.

Question 39

What does cholecystokinin (CCK) stimulate?

Answer 39

Production of pancreatic juice and release of bile ## Footnote CCK is secreted by I cells in the small intestine.

Question 40

What is the primary digestive organ of the body?

Answer 40

Small intestine

Question 41

What are the three subdivisions of the small intestine?

Answer 41

Duodenum, Jejunum, Ileum

Question 42

What is the role of enterocytes in the small intestine?

Answer 42

Production of digestive enzymes and absorption of nutrients

Question 43

Which enzymes are responsible for carbohydrate digestion in the small intestine?

Answer 43

Pancreatic amylase and brush border carbohydrases ## Footnote Brush border enzymes include glucoamylase and lactase.

Question 44

What are the products of protein digestion?

Answer 44

Free amino acids, dipeptides, and tripeptides ## Footnote Approximately 40% are free amino acids and 60% are dipeptides and tripeptides.

Question 45

What is the primary enzyme for lipid digestion produced by the pancreas?

Answer 45

Pancreatic Lipase

Question 46

What is the function of bile salts?

Answer 46

Emulsification and absorption of lipids ## Footnote Bile acids are synthesized from cholesterol.

Question 47

What is the absorption mechanism for glucose and galactose in the intestine?

Answer 47

Secondary active transport via SGLT-1 ## Footnote This mechanism utilizes the sodium gradient created by the Na+/K+ ATPase pump.

Question 48

What type of movement primarily propels food through the GI tract?

Answer 48

Peristalsis

Question 49

What is the primary function of the large intestine?

Answer 49

Fluid balance and production of feces

Question 50

What triggers the defecation reflex?

Answer 50

Distension of the rectum

Question 51

What is the role of hepatocytes?

Answer 51

Secretion of bile ## Footnote Hepatocytes synthesize bile acids and other components of bile.

Question 52

What is the composition of bile?

Answer 52

Bilirubin, bile salts, lecithin, cholesterol ## Footnote Bile plays a crucial role in digestion and excretion.

Question 53

What is the purpose of segmentation in the intestine?

Answer 53

Mixing and breaking apart food ## Footnote Segmentation involves back-and-forth action in the GI tract.

Question 54

What type of enzymes are produced by the pancreas for protein digestion?

Answer 54

Proteases ## Footnote Includes trypsinogen, chymotrypsinogen, and procarboxypeptidase.

Question 55

What is the order of the GI tract?