Setting The Scene- Physiology

Question 1

How is the gut controlled?

Answer 1

Autonomic nervous system
Enteric nervous system
Hormones

Question 2

What nerves do the sympathetic system form in the gut?

Answer 2

Presynaptic splanchnic nerves

Question 3

What region is the greater splanchnic?

Answer 3

T5-9

Question 4

What region is the lesser splanchnic nerve?

Answer 4

T10-11

Question 5

What region is the least splanchnic nerve?

Answer 5

T12

Question 6

What does the sympathetic nervous system do to the gut?

Answer 6

Shut down the gut

Question 7

What is the main parasympathetic nerve in the gut?

Answer 7

Vagus nerve

Question 8

As the gut turns what happens to the left vagus nerve?

Answer 8

Becomes anterior

Question 9

What do parasympathetic post ganglionic fibres release?

Answer 9

Ach

Peptides- gastrin releasing peptide and Vaso inhibitory peptide

Question 10

Where does the enteric nervous system operate?

Answer 10

Oesophagus to anus

Question 11

What are the two plexuses of the enteric nervous system?

Answer 11

Submucosal and myenteric

Question 12

What does the submucosal plexus do?

Answer 12

Controls epithelium

Secretion and blood flow

Question 13

What is the myenteric plexus?

Answer 13

Between circular and longitudinal muscle and controls muscle
Motility

Question 14

What cells produce hormones that help control the gut?

Answer 14

Enteroendocrine

Question 15

What do enterochromafin produce?

Answer 15

Produce paracrine hormones e.g. Histamine

Question 16

What does somatostatin do?

Answer 16

Inhibits G cells and histamine release

Question 17

What is neurocrine?

Answer 17

Peptides released by neurones in the GI tract after action potential

Question 18

What does gastrin releasing peptide do?

Answer 18

Increases release of gastrin from G cells

Question 19

What does gastrin do?

Answer 19

Increases gastric acid secretion

Question 20

What does cholecystokinin do?

Answer 20

Increase pancreatic and gall bladder secretion

Relaxes oddi sphincter

Question 21

What does Secretin and gastric acid inhibitor do?

Answer 21

Decreases gastric acid secretion

Question 22

If you have appendicitis why would you feel unlocalised pain over the stomach?

Answer 22

Stretching force of the visceral peritoneum does not have its own blood supply so if inflammed with go through the splanchnic nerves of the small intestine and larger intestine- lesser splanchnic nerve so T10 dermatome will be in pain

Question 23

With appendicitis when will pain be localised?

Answer 23

When the appendix enlarges it will come in contact with the parietal peritoneum which has a more localised blood supply

Question 24

Where would gallstones have pain?

Answer 24

Right upper quadrant and right shoulder tip

Question 25

Where would pancreatitis hurt?

Answer 25

Back pain

Question 26

Where would the oesophagus hurt?

Answer 26

Retrosternal pain

Question 27

What is motility of the GI tract used for?

Answer 27

Moving things along Mix content Grind content

Question 28

Everywhere is smooth muscle except for?

Answer 28

Pharynx Upper oesophagus External anal sphincter Simple columnar

Question 29

What is periodic contraction?

Answer 29

Propulsion and mixing

Question 30

What is tonic contraction?

Answer 30

Constant contraction

Question 31

What is peristalsis?

Answer 31

Propel contents in one direction contraction proximal Relaxation distal

Question 32

What is segmentation?

Answer 32

Contraction splits content then relaxes so the to and fro movement mixes

Question 33

What is mass movement?

Answer 33

Distal colon, rapid movement of contents into rectum causing gastrocolic reflex

Question 34

Does the sympathetic nervous system reduce motility?

Answer 34

Yes

Question 35

What is paralytic ileus?

Answer 35

Loss of GI contractility

Question 36

What is achalasia?

Answer 36

Failure of LOS to relax | Dysphagia

Question 37

What is hirchspriung disease?

Answer 37

Lack of enteric plexuses | Functional obstruction

Question 38

What is stomach acid used for?

Answer 38

Innate barrier to infection Prepares protein for digestion Activates enzymes

Question 39

What does HCO3 used for?

Answer 39

Neutralise the acid in GI tract

Question 40

Where are waste products secreted?

Answer 40

Mainly in the liver

Question 41

What are emulsifiers?

Answer 41

Bile salts Increases surface area of lipids Aids digestion and lipases Allows lipid break down products to be transported in the gut

Question 42

What does mucus do?

Answer 42

Protects against acidic environments e.g. Stomach Protects against bacteria in small intestine Harbours bacteria in large intestine Lubricates

Question 43

What do enzymes do?

Answer 43

Break down protein (protease) fat (lipases) carbohydrates (amylases)

Question 44

Where do secretions come from?

Answer 44

``` Acini of salivary glands Gastric glands Brunners glands Intestine glands Acini of exocrine pancreas Hepatocytes Goblet cells ```

Question 45

How are substances made small enough to absorb?

Answer 45

Mechanical breakdown | Chemical digestion

Question 46

What are active absorption cells?

Answer 46

Simple columnar

Question 47

What creates a large surface area in the GI?

Answer 47

Permanent folds Villi Microvilli

Question 48

What occurs if absorption is disturbed?

Answer 48

Diarrhoea Malnutrition Anaemia

Question 49

How is water absorbed?

Answer 49

Passively | Follows electrolytes and nutrients

Question 50

How is water absorbed after a meal?

Answer 50

Driven by nutrient coupled Na

Question 51

How is water absorbed between meals?

Answer 51

Na and Cl are absorbed

Question 52

Why and how is water harder to absorb in the colon?

Answer 52

Final bit so additional mechanism | Epithelial Na channel