lecture 1- overview of digestion

Question 1

Most common viral or food-borne bacteria

Answer 1

Gastroenteritis (Gastro)

Question 2

Gastroenteritis symptoms

Answer 2

Diarrhoea, abdominal pain, vomiting and fever

Question 3

Digestive systems primary function

Answer 3

Transfer nutrients, water & electrolytes from food into bodes internal environment

Question 4

Digestive system=

Answer 4

Digestive tract + accessory digestive organs

Question 5

Basic digestive function- 1. Motility

Answer 5

Muscular contractions that propel and mix the food (smooth muscle contractions)

Question 6

Basic digestive function- 2. Secretion

Answer 6

Exocrine glands secrete digestive juices. Endocrine glands secrete hormones

Question 7

Basic digestive function- 3. Digestion

Answer 7

Food is both mechanically and biochemically broken down into small units

Question 8

Basic digestive function- 4. Absorption

Answer 8

The small units (with water and electrolytes) are transferred into the blood and lymph

Question 9

Mouth

Answer 9

Mastication (breaking food into smaller pieces and a little carb digestion) (saliva, mucus, amylase, lysozyme)

Question 10

Pharynx and Oesophagus

Answer 10

Swallowing and transporting food from the mouth to stomach (mucus)

Question 11

Stomach

Answer 11

Mixing, churning and digestion (no absorption of foodstuffs) making of chyme, gastric juices, HCI, pepsin

Question 12

Small Intestine

Answer 12

Digestion and most absorption (with help from secretions from liver and pancreas)

Question 13

Large Intestine

Answer 13

Completes absorption of water and electrolytes (faeces remain)

Question 14

Accessory Organs- Salivary glands

Answer 14

Secretions help in lubrication, antibacterial and begin digestion

Question 15

Accessory Organs- Pancreas

Answer 15

Vital for digestion, enzymes for all food categories and alkaline sol.

Question 16

Accessory Organs- Liver

Answer 16

Secretes bile continuously, biliary system, bile salts storage and concentration

Question 17

Accessory Organs- Gallbladder

Answer 17

Secretes bile continuously, biliary system, bile storage and concentration

Question 18

Mucosa

Answer 18

highly folded, lining the luminal surface of the digestive tract (3 layers)

Question 19

Mucous membrane

Answer 19

protective surface barrier, epithelial tissue with exocrine, endocrine and ‘absorptive’ cells

Question 20

Lamina propria

Answer 20

thin middle layer of connective tissue containing the gut-associated lymphoid tissue

Question 21

Muscularis mucosa

Answer 21

sparse layer of smooth muscle which upon contraction can expose different areas of surface folding

Question 22

Submucosa

Answer 22

connective tissue containing larger blood and lymph vessels and a nerve network- the submucosal plexus

Question 23

Muscularis externa

Answer 23

major smooth muscle coat, contains the myenteric plexus

Question 24

Serosa

Answer 24

outer connective tissue secretes a serous fluid and is continuous with the mesentery

Question 25

Propulsive movements (peristalsis)

Answer 25

forward movement

Question 26

Mixing movements (segmentation)

Answer 26

mix in with digestive juices, expose to absorptive surfaces

Question 27

Digestion- Hydrolysis

Answer 27

is used in the digestion of proteins, fats and carbs

Question 28

Regulation 4 factors

Answer 28

1 Autonomous smooth muscle function, 2 Intrinsic nerve plexuses, 3 extrinsic nerves, 4 gastrointestinal hormones

Question 29

Extrinsic nerves

Answer 29

sympathetic and parasympathetic systems act on intrinsic nerves, hormone secretion

Question 30

Gastrointestinal hormones

Answer 30

Enteroendocrine cells in the mucosa of the GIT release hormones into the blood where they exert excitatory or inhibitory effects on smooth muscle and exocrine cells

Question 31

Swallowing 3 stages

Answer 31

Oral (voluntary phase), Pharyngeal (involuntary phase), Oesophageal stage (involuntary phase)

Question 32

Pharyngo-oesophageal (upper sphincter)

Answer 32

prevents excess air from entering GIT

Question 33

Gastro-oesophageal (lower sphincter)

Answer 33

keeps out stomach contents, otherwise ‘heart burn’

Question 34

Primary peristalsis

Answer 34

preceded by pharyngeal phase, controlled by swelling centre

Question 35

Secondary peristalsis

Answer 35

can occur without pharyngeal phase if oesophagus distended e.g. if food is stuck, pressure receptors trigger intrinsic nerve plexus leading to stronger force

Question 36

Swalling disorder

Answer 36

Dysphagia (disordered eating- leads to aspiration, pneumonia, malnutrition, dehydration, airway obstruction)

Question 37

Gastrointestinal tract major functions

Answer 37

ingestion, digestion, absorption, and defaecation