GI Physiology

Question 1

prehension?

Answer 1

the act of moving food into the mouth

Question 2

what is prehension controlled by?

Answer 2

the CNS - primarily the facial nerve, the glossopharyngeal nerve and the motor branch of the trigeminal nerve

Question 3

mastication?

Answer 3

chewing - the first act of digestion

Question 4

chewing?

Answer 4

the breakdown of food particles to increase SA for digestion

Question 5

saliva secretions?

Answer 5

moistens and lubricates food

Question 6

type of epithelium in mouth lining?

Answer 6

stratified squamous epithelium

Question 7

which neurones does the mouth contain?

Answer 7

terminal branches of sensory neurone - prepares stomach for type of food it is about to encounter

Question 8

4 types of salivary glands?

Answer 8

zygomatic, parotid, sublingual and mandibular

Question 9

describe mucous saliva?

Answer 9

thicker/more viscous
important for binding food into bolus

Question 10

which glands secrete mucous saliva?

Answer 10

zygomatic and sublingual

Question 11

describe serous saliva

Answer 11

watery and contains amylase (starches into simple sugars)

Question 12

which glands secrete serous saliva?

Answer 12

parotid

Question 13

mostly what type of saliva for birds?

Answer 13

mostly mucous type

Question 14

dog species specific saliva?

Answer 14

no amylase

Question 15

salivary gland control?

Answer 15

purely by neurones, no hormonal control

Question 16

what are salivary glands regulated by?

Answer 16

by the parasympathetic nervous system

Question 17

describe salivary gland control:

Answer 17

nerve fibres end on the acini
stimulation results in increased saliva production
salivary secretory cells also contain B-adrenergic receptors

Question 18

What activates the B-adrenergic receptors?

Answer 18

the sympathetic nerve stimulation (fight or flight)

Question 19

component of saliva that enables the lubrication function?

Answer 19

mucin (glycoproteins) - mix with water to form mucous

Question 20

component of saliva that enables the pH regulation function?

Answer 20

HCO3-
neutralisation

Question 21

component of saliva that enables the antibacterial function?

Answer 21

lysozymes and antibodies
keep the amount of bacteria in check

Question 22

slide 11

Question 23

what is the pH of the saliva in a ruminant?

Answer 23

alkaline (bicarbonate phosphate)

Question 24

considering its pH, what is the importance of saliva in ruminants?

Answer 24

necessary for neutralisation of fermentation products

Question 25

how many litres of saliva can an adult cow excrete?

Answer 25

100-200 litres of saliva a day

Question 26

slide 12

Question 27

6 steps of the involuntary phase of deglutition:

Answer 27

Breathing stops momentarily Soft palate is elevated The tongue is pressed against the hard palate The glottis is pulled under the epiglottis When all openings into the pharynx are closed a wave of muscualr contrxaction passes over the walls of the pharynx the upper oesophageal sphincter releases

Question 28

invoiluntary phase of deglutiion controlled by?

Answer 28

by motor neurones in vsrtious centres of the brainstem

Question 29

drooling lotsd and panting and difficulty swallowing?

Answer 29

facial nerve is impacted - neurological

Question 30

striated muscle AKA?

Answer 30

skeletal muscle

Question 31

oesophageal muscle types?

Answer 31

striated and smooth muscle

Question 32

skeletal muscle in dogs, cattle and sheep?

Answer 32

the entire length of the oesophagus is striated

Question 33

skeletal muscle in horses primates and cats?

Answer 33

a portion of the oesophagus is smooth muscle

Question 34

muscle control of striated muscle?

Answer 34

vagus nerve

Question 35

muscle control for smooth muscle?

Answer 35

ENS (gut specific nervous system)

Question 36

in many species, what is the action of the lower sphincter aided by?

Answer 36

by the anatomical attachment to the stomach

Question 37

peristalsis?

Answer 37

exists in all levels of gut, movement of substances throughout the gut all the time, a moving ring of constriction pushing food through consists of primary and secondary waves

Question 38

longitudinal muscles contract

Answer 38

food moves forward

Question 39

circular muscle contract - longitudinal relax?

Answer 39

food moves forward

Question 40

when does the sympathetic nerve stimulation of the B-adrenergic receptors occur, why and what is produced?

Answer 40

this stimulation has little to do with digestive activity occurs in carnivores about to attack produces a smaller quantity of viscous saliva

Question 41

saliva used for starch digestion in which species and how?

Answer 41

omnivores, single-stomached herbivore and some avian USING amylase

Question 42

saliva used for fat digestion in which species and how?

Answer 42

in young calves and USING lingual lipase

Question 43

saliva used for thermoregulation in which species and how?

Answer 43

in canine and rodent USING panting and spreading saliva (over body - evaporative cooling)

Question 44

saliva used for binding tannins in which species and how?

Answer 44

in leaf-eaters USING binding proteins

Question 45

saliva used for providing urea in which species and how?

Answer 45

in animals with fore-stomachs Urea diffuses from blood into saliva

Question 46

problems in ruminants (cows) with being able to excrete lots of saliva in one day?

Answer 46

H2O and electrolyres secreted in saliva must be reabsorbed rapidly cow could become dehydrated in abnormal circumstances cows become acidotic

Question 47

two phases of deglutition?

Answer 47

voluntary and involuntary

Question 48

voluntary stage of deglutition:

Answer 48

chewed food is moulded into a bolus and moved to the pharynx

Question 49

involuntary stage of deglutition:

Answer 49

initiated by the voluntary

Question 50

describe the control of deglutition:

Answer 50

efferent nerve fibres travel in the facial, vagus and hypoglossal and glossopharyngeal nerves

Question 51

clinically, what do problems with prehension, mastication and deglutition frequenctly relate to?

Answer 51

relate from neurological lesions e.g. laryngeal paralysis - panting and swallowing issues

Question 52

what does wall of oesophagus consist of?

Answer 52

mucosa, submucosa muscularis and serosa

Question 53

what does muscularis layer consist of?

Answer 53

circular longitudinal

Question 54

what does mucosa layer consist of?

Answer 54

epithelium lamina propria muscularis mucosae

Question 55

what is happening when deglutition is not taking place?

Answer 55

the body of the oesophagus is relaxed but both sphincters are tightly constricted

Question 56

what two waves are there in peristalsis?

Answer 56

primary (stronger) and secondary (weaker) waves