Control of UGF Flashcards

1
Q

Sympathetic neurotransmitter

A

Noradrenaline

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2
Q

Sympathetic receptors

A

Adrenoceptors (alpha + beta)

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3
Q

Parasympathetic neurotransmitter

A

Acetylcholine

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4
Q

Parasympathetic receptors

A

Muscarinic

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5
Q

In the sympathetic nervous system, what does Acetylcholine act on?

A

Nicotinic receptor

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6
Q

Sympathetic agonist

A

Noradrenaline @ alpha + beta-adrenoceptors

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7
Q

Sympathetic antagonist

A

Atenolol @ Beta-adrenoceptors

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8
Q

Parasympathetic agonist

A

Acetylcholine @ muscarinic receptors

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9
Q

Parasympathetic antagonist

A

Atropine @ muscarinic receptors

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10
Q

Salivation + benefits

A

Glandular production of saliva

  • aids speech
  • promotes dental hygiene
  • allows mastication (chewing)
  • adds fluid
  • starts digestion of starches (amylase)
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11
Q

Production of saliva is under _________ control

A

Autonomic control - parasympathetic (acetylcholine at muscarinic receptors)

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12
Q

Stomach secretes __ litres per day

A

2

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13
Q

What pH is the Stomach + benefit

A

Low = 1 - 1.5 = acidic

  • acidity sterilises food to prevent food poisoning
  • optimal pH for enzyme
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14
Q

Chief cells of gastric mucosa secrete

A

Pepsinogens

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15
Q

What does the acid environment activate

A

pepsinogens to form pepsins

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16
Q

What is pepsins

A

Endopeptidase - proteolysis of (breaks down) proteins to polypeptides

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17
Q

Cephalic phase

A

prepares stomach for food arrival - begins prior to food entry

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18
Q

What nervous system is stimulated by cephalic phase

A

Parasympathetic

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19
Q

Cephalic phase is stimulated by…

A

Sight, smell, taste

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20
Q

(Cephalic phase) What does parasympathetic system stimulate

A

Acid release

Gastrin release into blood

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21
Q

What releases gastrin

A

G cells

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22
Q

Gastric phase

A

Occurs while food is in the stomach

  • Stretch receptors detect distension of stomach
  • Release of ACh, histamine + gastrin
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23
Q

What is secreted in gastric phase

A

Acid, pepsinogen, mucus

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24
Q

What releases histamine

A

Mast cells

25
Q

(Gastric phase) What stimulates g cells to secrete gastrin)

A

Prescence of peptides (food)

26
Q

Intestinal phase

A

occurs when chyme enters small intestine

- presence of chyme in duodenum opens pyloric sphincter

27
Q

(Intestinal phase) What inhibits secretion

A

CCK inhibits acid

28
Q

What do acinar cells secrete

A

amylase + electrolytes with similar tonicity to plasma

29
Q

What modifies secretion of saliva

A

Striated + excitatory ducts

30
Q

What reduces saliva production + flow

A
Muscarinic antagonist (antimuscarinic, parasympathetic)
e.g. old tricylic antidepressants
31
Q

Effect of old tricylic antidepressants

A

Dry mouth, urinary retention, constipation + blurred vision

32
Q

What will enhance/cause salivation

A

Muscarinic agonist (inhibitors of acetylcholinesterase)

33
Q

What increases acid secretion

A

Histamine (H2 receptors)
Gastrin
Acetylcholine (M-receptors = M3 on parietal cells)

34
Q

Decreases acid secretion

A

Prostaglandins (E2 + I2)

cytoprotective via bicarbonate + mucus release (from superficial epithelial cells)

35
Q

What is histamine + what is it responsible for

A

Endogenous mediator

Responsible for skin rashes + gastric acid secretion

36
Q

What are Histamine H1 receptors responsible for

A

Allergies

- antihistamines bind e.g. loratadine

37
Q

What are H2 receptors ressponsible for

A

Gastric acid secretion

- H2RA e.g.ranitidine to treat dyspepsia

38
Q

What is gastrin

A

Peptide hormone

Agonist at CCK

39
Q

What releases gastrin

A

Antral cells to mediate gastric phase

40
Q

where is arachidonic acid

A

Cell membranes

41
Q

What releases arachidonic acid

A

Phospholipase A2

42
Q

2 pathways for arachidonic acid metabolism

A
  • Cyclooxygenase (COX): prostanoids

- Lipoxygenase: leukotrienes

43
Q

Examples of NSAIDs

A

Ibuprofen, aspirin, diclofenac

44
Q

What do NSAIDs inhibit

A

NSAIDs

45
Q

Mastication

A

chewing and addition of saliva

46
Q

Salivary amylase

A

(stimulated by parasympathetic) Enzyme to start hydrolysis of starch

47
Q

pH of duodenum

A

5-6

48
Q

Duodenum secretes…

A

Pancreatic enzymes

  • lipase
  • amylases
  • proteolytic enzyme

Bile (secreted by gallbladder) into duodenum to emulsify fats

49
Q

Function of Intrinsic factor

A

Secreted by parietal cells to help absorb Vit B12

50
Q

Stomach cancer

A
Poor prognosis (18% - 5 year survival)
Present with dyspepsia
- bleeding
- weight loss
- > 55 years 
- abdominal masses
51
Q

Prostanoids/prostaglandins

A

Family of AA metabolites

  • PGs = inhibit acid secretion
  • PGI2 = inhibits platelet aggregation (vasodialtion)
  • TXA2 = stimulate platelet aggregation (vasoconstriction)

Also cause:

  • pain
  • inflammation
  • temperature
  • asthma
  • uterine contractions
  • miscarriage
52
Q

Production of cyclic AMP

A
Hormone (1st messenger) binds to receptor
receptor activates G protein
G protein activates adenylate cyclase
Adenylate cyclase converts
ATP to cAMP (2nd messenger)
53
Q

Function of cAMP

A

Stimulate acid secretion

54
Q

PGE2 PGI2

A

Inhibit increase in cAMP suppress proton pump activity

Cytoprotection: release mucus + bicarbonate

55
Q

Proton pump activated

A

Activated by phosphorylation + calcium

Dynamic: produced in cell + cycles to membrane

56
Q

Gastrin cause Ca-dep or cAMP

A

Ca-dep

57
Q

ACh cause Ca-dep or cAMP

A

Ca-dep

58
Q

Histamine cause Ca-dep or cAMP

A

cAMP