GIT,Physiology Flashcards
Food ingestion depends on
Hunger and appetite
Difference between hunger and appetite
Hunger:No specific food desire,can eat anything
Appetite:Desire to eat specific food e.g chicken,omelette
Layers of GIT and name them
4:in to out
1)mucosa(epithelium +CT+some muscles)
2)submucosa(CT)
3)Muscularis Externa(inner circular smooth muscle,outer longitudinal smooth muscle)————>motor control
4)serosa/Serosa adventitia (CT)
Syncytium caused by
Gap junctions in muscle bundle
Smooth muscle bundle
A) dia of Fiber and length?
B)number of fiver in bundle
Dia:2 -10 micrometer
Length:200 to 5 micrometer
No:1000
Types of waves in git and caused by
A)Slow waves——>Na channels in Interstitial cells of cajal
B)Spike potential——->Na Ca Channels
Frequency of slow waves
3 [stomach)
12(duodenum)
9 (terminal ileum)
Threshold of spike potential
-40
Stimulus of depolarisation
Muscle stretch,Ach released by parasympathetic endings,hormones
Hyperpolarisation (no git motility,cells less excited) caused by
Epinephrine,norepinephrine released in stress condition,Sypatethic stimulation
Tone
Partial state of contraction
Tonic contraction caused by
Excessive spike potential due to stimulus or hormones
Nervous system of GIT
Enteric Nervous System
Inhibitory neurotransmitter of myenteric plexus
VIP(vasoactive intestinal peptide)
Components and functions of enteric nervous system
2:
Meißners:bwMuscles Control git movement and motility
Meisters:in submucosa control local hormone secretion,blood flow,absorption
Sensory ending of git stimulated by
Mucosa irritation,excessive distension,chemicals
Sympathetic parasympathetic function
S;release norepinephrine ,inhibit smooth muscle/neuron,motility decrease passage of food difficult and give versa
Gastro intestinal reflexes types
1)within gut wall——>peristalsis,secretion,mixing contents
2)between git and prevertebral sypatethic ganglia——->gastrocolic
>enterogastric
>colonoileal
3)between git and spinal cord/brain stem
>vagovagal
>pain
>defecation
Hormones of GIT
*Gastrin,Cholecystokinin,Secretin,GIP,Motilin
Hormones of GIT
*Gastrin,Cholecystokinin,Secretin,GIP,Motilin
Peristalsis
Involuntary rhythmic muscle contraction that pushes food forward in git
Peristalsis occurs when
Distension of wall,physical/chemical irritant,parasympathetic stimuli
My enteric plexus inhibited by
Atropine which inhibit cholinerguc endings thus no peristalsis
Movement of git types
Peristalsis and mixing