salivary, gastric + pancreatic secretion

Question 1

what do the salivary glands secrete ?

Answer 1

• electrolytes

- proteins

Question 2

what are the names of the salivary glands ?

Answer 2

sublingual gland
submandibular gland
parotid gland
buccal glands

Question 3

what is the maximum rate of saliva flow ?

Answer 3

1ml/min.g

Question 4

describe the acinar cells

Answer 4

arranged as end pieces

surround small central lumen

Question 5

describe the organisation of the salivary glandular epithelium :

Answer 5

acinar cells - intercalated duct- large ducts- excretory ducts - mouth

Question 6

how is parasympathetic stimulation of the salivary gland mediated ?

Answer 6

chorda lingual nerve

Question 7

what does parasympathetic stimulation cause ?

Answer 7

• evoke fluid secretion
• increase blood flow
• increase 02 consumption

Question 8

how does sympathetic secretion effect the salivary gland ?

Answer 8

causes vasoconstriction

scanty viscous secretion in rich proteins

Question 9

what stimulates the salivary reflex ?

Answer 9

• taste
• touch
• smell

Question 10

how is salvia formed ?

Answer 10

2 stage process
isotonic primary fluid formed by acinar cells
fluid is modified in the striated duct by reabsorption of Na + Cl
and secretion of K + HCO3

Question 11

what is the effect of neurotransmitters + hormones on the basolateral membrane of the acinar cells ?

Answer 11

increase intracellular Ca = activation of K channels in basolateral membrane
possible increase of Cl channels in luminal membrane

Question 12

what are the 3 operating basolateral transport proteins in a steady state ?

Answer 12

K+ channel
Na/K pump
N/K/2Cl co transporter

Question 13

how does Na cross the apical membrane ?

Answer 13

follows through paracellular space drawing water through + between cells

Question 14

what happens to the Cl + K conductance ?

Answer 14

increases when stimulation stops

Na/K pump + co transporter restore intracellular KCL concentrations

Question 15

how is the voluntary phase of swallowing initiated ?

Answer 15

separation of bolus of food in mouth
bolus is moved upwards + backwards by tongue
this forces bolus into esophagus + activates tactile receptors that initiate swallowing

Question 16

what does the pharyngeal phase of swallowing involve ?

Answer 16

pulling of soft palate upwards
inward movement of palatopharyngeal fold towards one another
prevents reflux into the nasopharynx

Question 17

how is the entry of food into the trachea prevented ?

Answer 17

vocal cords are pulled together

epiglottis covers the opening to larynx

Question 18

how is food forced through ?

Answer 18

upper esophageal sphincter relaxes
pharynx contracts forces bolus into pharynx
persistatic waves force food bolus through relaxed esophageal sphincter

Question 19

how is the gastirc surface protected and what by ?

Answer 19

thin film of mucous

produced by epitheilal cells

Question 20

what are the 3 glands in the gastric mucosa ?

Answer 20

• cardiac glands
• pyloric glands
• oxyntic glands

Question 21

where is the cardiac glands found ?

what is there role ?

Answer 21

found in the esophageal end is highly branched
is coiled with few/no peptic or oxyntic cells
secretes mucous + some electrolytes

Question 22

where are the pyloric glands found ?

what is there role ?

Answer 22

found in deep gastric pits , duodenum of stomach, pyloric sphincter and antrum of stomach
secrete alkaline mucous juice + some electrolytes

Question 23

where are the oxyntic glands found?

what is there role ?

Answer 23

occupy fundus + body of stomach

key site of gastric HCl secretion

Question 24

what are surface mucus cells made up of ?

what do they secrete ?

Answer 24

columnar epithelium

neutral carbohydrates

Question 25

what are mucous neck cells ? | what do they secrete ?

Answer 25

they are stem cells for epithelial replacement | acidic glycoproteins

Question 26

describe the cell structure of parietal/ oxyntic cells :

Answer 26

lots of mitochondria specialised intracellular canaliculi microvilli on lumen

Question 27

what is a benefit of canaliculi ?

Answer 27

increase SA

Question 28

where does HCL secretion occur ? | how does HCL secretion occur ?

Answer 28

on parietal cells | basolateral receptors become activated by Ach, histamine and gastrin

Question 29

what are chief cells ?

Answer 29

cells that secrete pepsinogen

Question 30

where is gastrin released from ?

Answer 30

G cells of antral mucosa

Question 31

where does gastrin bind to ?

Answer 31

bind to CCK-2 receptor on enterochromaffin like cells

Question 32

how does gastrin release cause HCL production ?

Answer 32

binds to enterochromaffin like cells which causes the release of histamine histamine binds to H2 receptors on parietal cells

Question 33

what is released to inhibit further gastrin release ? | where is it released from ?

Answer 33

somatostatin | D-cells

Question 34

what is gastric juice made from ?

Answer 34

HCl from parietal cells | alkaline component containing peptic cells + electrolytes

Question 35

what are the 5 phases of gastric acid secretion ?

Answer 35

- basal (fasting) - post-prandial (stimulated) - cephalic - gastric - intestinal

Question 36

what activated the cephalic phase ? | what is it mediated by ?

Answer 36

activated by sight , smell, taste + chewing of food | mediated by efferent impulses through vagus fibres to stomach

Question 37

what activates gastric secretion ?

Answer 37

distension + chemical composition of food factors

Question 38

what activates intestinal secretion ? | when does it occur ?

Answer 38

stimulated by liver extract, peptone, amino acid mixtures | occurs after all extrinsic nerves between intestines + stomach are severed

Question 39

what is zollinger- ellison syndrome ?

Answer 39

condition where one or more tumours form in your pancreas or the duodenum

Question 40

what causes zollinger-ellison syndrome ?

Answer 40

large amounts of gastrin is secreted which stimulate ECL , which release histamine which binds to parietal cells = more HCL produced excess HCL leads to peptic ulcers + diarrhea

Question 41

how is the head, body + tail of the pancreas drained ?

Answer 41

drained by main pancreatic duct | enters the duodenum through ampulla of Vater

Question 42

describe the bloody supply + lymphatics of the pancreas :

Answer 42

accompany duct system to finest termini in pancreatic acini

Question 43

what nerves innervate the pancreas ?

Answer 43

vagus + sympathetic

Question 44

where is secretin released from ? | how does this act on the small intestine ?

Answer 44

small intestine | enters pancreas via circulation + causes the release of bicarbonate

Question 45

where is cholecystokinin released from ? | what effect does it have on the pancreas ?

Answer 45

released from small intestine | acts on acinal cell receptors + release proenzyme secretion