Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

An Sc 311 Midterm 1 > Lecture 5 - Motility > Flashcards

Lecture 5 - Motility Flashcards

(61 cards)

Start Studying
1
Q

Structures involved in prehension and chewing

A

Lips, tongue, incisors = procure the feed
Molars = grind the feed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do molars vary in carnivores, omnivores and herbivores

A

Carnivores + omnivores = vertical movement
Herbivores = lateral movement (side to side)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Indications that a horse should be floated

A

Dropping feed
Losing weight
Head tossing
Balls of chewed hay coughed out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Two phases of swallowing

A

Oropharyngeal phase
Oesophageal phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the oropharyngeal phase of swallowing

A

Food pushed back by tongue, tongue prevents return to mouth
Uvula blocks nose
Glottis/epiglottis block access to lungs
Swallowing center in medulla coordinates and inhibits respiratory center
Pharyngoesophageal sphincter opens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the oesophageal phase of swallowing

A

Peristaltic wave every 5-9s
Skeletal muscle
Oesophagogastric/cardiac sphincter opens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is peristalsis

A

Waves of contraction
Rapid propulsion
Relaxation and contraction of longitudinal and circular muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the peristaltic reflex programmed by

A

The enteric nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the three parts of the stomach

A

Fundus
Corpus
Antrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the job of the fundus

A

Receptive relaxation (makes room when food enters)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What molecules are involved in relaxation of the fundus? What induces them?

A

Nitric oxide and vasoactive intestinal polypeptide
Induced by ACh

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of the corpus

A

Mixing vat for saliva, food and gastric secretions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the role of the antrum

A

Propulsion of food through the pyloric sphincter to the duodenum
Size discrimination (small pieces only)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the antrum controlled by

A

Distention
Parasympathetic NS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where/how does mixing occur in the stomach

A

In the corpus
Peristalsis acts against closed pyloric sphincter
HCl and pepsin stirred in
Protein digestion begins and lipid droplets form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does gastric emptying occur

A

Peristalsis
Pyloric shincter opens
Chyme (digesta) enters duodenum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What regulates gastric emptying

A

Force of contraction
Signals from duodenum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is gastric emptying

A

Empty the stomach into the SI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What factors increase gastric emptying

A

Neural control (distension of stomach wall, increased parasympathetic)
Endocrine control (gastrin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What factors decrease gastric emptying

A

Neural control (chemoreceptors, osmoreceptors, mechanoreceptors at duodenum, sympathetic NS)
Endocrine control (CCK, secretin, gastric inhibitory peptide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why does increased sympathetic NS activity decrease gastric emptying

A

In fight or flight mode, do not want to waste energy on digestion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is segmentation

A

Most common form of motility (contraction of circular muscle)
Alternating contractions = mixing (not directional)
Freq decreases distally duodenum -> colon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Motility in the colon

A

Haustration (segmentation) = mixing and movement
Clearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Stimulus, sensor, signal, effector, response and effect of motility regulation in the duodenum

A

Stimulus = chyme distend walls
Sensor = stretch receptors in wall
Signal = nervous
Effector = smooth muscle
Response = vigorous segmentation
Effect = removal of stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Stimulus of motility in the ileum/colon
Protein/digestion in stomach Gastrin released from stomach
26
Two responses to stimulus in ileum/colon
1. Gastro-ileal reflex (stimulates segmentation in ileum, inhibits (opens) ilea-caecal sphincter) 2. Gastro-colic reflex (mass movement in colon)
27
What are tonic contractions? Examples?
Sustained (long-term) contraction of muscle Divide GIT into functional segments e.g. esophageal sphincter, pyloric sphincter, ileocecal sphincter
28
What do the interstitial cells of cajal do
set a constant pulse in smooth muscle cells and are considered the pacemakers of the GIT
29
What smooth muscle layers make up the GIT
Circular and longitudinal muscle layers
30
Smooth muscle cells have an intrinsic rhythm of ________________________________________
depolarization and repolarization
31
When do contractions occur in smooth muscle
When depolarization is high enough (reaches the threshold) to cause action potential
32
Which hormones regulate depolarization for contraction
Acetylcholine (parasym) increase resting basal membrane potential = stimulates AP and contraction Norepinephrine (sym) decrease resting basal membrane potential = prevent AP and contraction
33
Small intestine motility in the fed state
Segmentation reflex (mixes contents, regulated by ENS)
34
Small intestine motility in fasted state (post meal)
Migrating myoelectric complex - peristaltic activity - uninterrupted in herbivores
35
Three phases of migrating myoelectric complex
1. Quiescent period (nothing) 2. Intermittent contraction (cross threshold periodically) 3. Powerful propulsion sweeps intestinal contents out (contract every time)
36
Functions of large intestine motility
Microbial digestion Reabsorption of water/electrolytes
37
What kind of motility is there in the large intestine
Stationary haustral contractions (mixing) Peristaltic contractions Antiperistaltic movement (fill the cecum) Aboral mass movement (evacuate entire length of colon = defecation)
38
Aboral vs oral
Aboral = away from mouth Oral = towards mouth
39
What can alter GIT motility
Stomach worms = increase gastric emptying -> MMC reduced and replaced with migrating action potential complex (faster)
40
Where is the vomiting centre
Medulla
41
What is the vomiting centre activated by
Visceral afferents anywhere in GIT (nerves to brain) due to blockage, mucosal irritation Vestibular stimulation (motion sickness) Efferent nerves activate upper GIT and diaphragm and abdominal muscles
42
Slide 27**
vomiting
43
What does the vomiting centre do pre-vomit
Close soft palate, close glottis Respiration stops Abdominal pressure (diaphragm contracts)
44
Major concerns surrounding vomiting
Significant fluid and electrolyte loss (dehydration) Acid-base imbalance
45
Plexuses of the enteric nervous system
Myenteric (Auerbach) plexus Submucosal (Meissner) plexus
46
Characteristics of the myenteric plexus
Between circular and long smooth muscle Extensive, long interneurons Sympathetic and parasympathetic
47
Characteristics of the submucosal plexus
In submucosa Interneurons minor Only parasympathetic
48
Afferent neurons aka? Efferent neurons aka?
Sensory, motor
49
Slide 32, 33
Afferent and efferent neurons
50
What nervous system do efferent and afferent neurons fall under
Peripheral NS
51
What nervous system do the sympathetic and parasympathetic pathways fall under
Peripheral NS Autonomic neurons
52
Two types of efferent neurons
Autonomic Somatic
53
What kind of activity do the autonomic effector tissues have
Intrinsic (spontaneous or tonic) activity
54
What is the sympathetic NS
Inhibit digestion Fear, fight or flight responses Postganglionic neurons release norepineephrine (stop enteric NS)
55
What is the sympathetic NS
Inhibit digestion Fear, fight or flight responses Postganglionic neurons release norepinephrine
56
What does the sympathetic NS decrease
GI tract smooth muscle motility Exocrine secretion (into gut) Exocrine secretion
57
What is the parasympathetic NS
Promotes digestion Postganglionic neurons release acetylcholine
58
What does the parasympathetic NS increase
GI tract smooth muscle motility Exocrine secretion Endocrine secretion
59
Slide 36
Symp and parasymp
60
What is an ileus
Caused by inhibition of motor activity Increased activity upstream, decreased downstream Blocked long time = distention, sympathetic reflex enters CNS = pain Common after surgery
61
Slide 38**
Summary of ENS

An Sc 311 Midterm 1 (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions