Gastrointestinal Physiology Flashcards
What’s the length of the gastrointestinal tract?
10m long
The gastrointestinal tract extends from the _______________ to _________________
Mouth
Rectum
Mouth - Oral cavity - ___________________ - Esophagus - Stomach - __________________ - Large intestine
Fill in the gaps for the functional organisation of the gastrointestinal tract
Pharynx (Oropharynx)
Small intestine
The innermost layer of the GIT wall is _________________
Mucosa
What three layers make up the mucosa of the GIT?
Epithelium
Lamina propria
Muscularis mucosae
The submucosa is the ________________ layer of the GIT wall (moving outwards)
Second
The bundle of nerve fibres found in the submucosa of the gastro-intestinal wall is called ____________________
Meissner’s plexus
The submucosal plexus is otherwise referred to as__________________
Meissner’s plexus
The muscular layer of the gastro-intestinal wall consists of two sub layers called _______________ and _______________
Longitudinal
Circular
The myenteric plexus is otherwise known as __________________
Auerbach’s plexus
The myenteric plexus is located where _________________
In-between the longitudinal and circular sublayers of the GIT wall’s muscular layer
The GIT receives innervation from the ________________ nervous system
Enteric
The ________________ nervous system is often referred to as the “Second brain”
Enteric
Smooth muscles are located throughout the body.
True/False
True
Smooth muscle cells are said to be ____________ in shape
Fusiform
Smooth muscles are surrounded and separated by a connective tissue layer called _________________
Endomysium
How many smooth muscle layers are there?
2
Longitudinal
Circular
Smooth muscles are non-striated because ________________
They have no sarcomeres or myofibrils
Goblet cells in the GIT secrete _______________
Mucus
G-cells in the GIT secrete _____________
Gastrin
Parietal cells in the GIT secrete _____________ and ______________
HCL and Intrinsic factor
Chief cells in the GIT secrete ___________
Pepsinogen
Oxyntic cells are another name for ______________
Parietal cells
Peptic cells are another name for ____________
Chief cells
G-cells secrete _________ in response to _________________
Gastrin
Stretch from food entering the stomach
Parietal cells produce secretion in response to __________________
Stimulation from Gastrin
______________ is converted to pepsin in the presence of _______________
Pepsinogen
HCL
____________________, _______________ and ______________ are the phases of gastric acid secretion
Cephalic
Gastric
Intestinal
Secretion of acid in response to sight, smell or thoughts of food occurs in what phase of gastric acid secretion?
Cephalic phase
Secretion of acid in response to entry of food into the stomach occurs in what phase of gastric acid secretion?
Gastric phase
Secretion of acid in response to food entering the duodenum occurs in what phase of gastric acid secretion?
Intestinal phase
Gastric secretion and motility are maintained in what phase of gastric acid secretion?
Gastric phase
Gastric secretion and motility are inhibited in what phase of gastric acid secretion?
Intestinal phase
______________ is a hormone secreted in the small intestine to inhibit gastrin release
Cholecystokinin [CCK]
The process whereby food eaten doesn’t get to the stomach is called _____________
Sham feeding
During HCL production, CO² and H2O combine to form Carbonic acid (H2CO³) in the presence of __________________
Carbonic anhydrase
During HCL production, Carbonic acid formed from CO² and H2O splits into _________ and _____________
H+ and Bicarbonate (HCO³)
Smooth muscle fibers in the GIT are ____________ micrometers in length
200-500
Smooth muscle fibers in the GIT are ____________ micrometers in diameter
2-10
Action potentials generated anywhere within the muscle mass of a smooth muscle travels in all directions.
The smooth muscle fiber is said to function as a ___________________ in this case
Syncytium
Electrical waves in the GIT are either _____________ waves or _____________
Slow waves or Spikes
Slow, undulating changes in the resting membrane potential of the GIT muscle fibers are called __________________
Slow waves
Sinoatrial nodes serve as pacemakers of the heart, _________________ are the pacemakers of smooth muscles cells
Interstitial cells of Cajal
_________ is the normal resting membrane potential of the smooth muscle cells of the gut
a) -40 to -50 millivolts
b) -40 to -60 millivolts
c) -50 to -60 millivolts
d) -50 to -70 millivolts
C
-50 to -60 millivolts
Generation of action potential in the gastrointestinal tract is the same as generation of action potential in nerve fibers.
True/False
False
Action potential in the GIT is generated through Calcium-Sodium channels
The PH of bile is ________
7.8
The total daily volume of juices in the GI tract is about ____________ml
6700
____________________, ___________________ and _________________ are the major glands of salivation
Parotid
Sublingual
Submandibular
The average value for daily secretion of saliva is ___________ml
1000
The serous secretion of saliva contains ______________ as the mucus secretion of saliva contains _____________
Ptyalin (a-amylase)
Mucin
The submandibular (submaxillary) glands of salivation secrete what type of secretion?
Both serous and mucus secretions
A physiological phenomenon that occurs after a meal, characterised by a temporary increase in the pH (alkalinity) of the blood in response to the digestive processes that take place after eating, is called?
Post- Prandial alkaline tide
Mention the lengths of the different parts of the small intestine
Duodenum: 1ft
Jejenum: 8ft
Ilium: 12ft
The PH of saliva is ___________
6.0-7.0
The PH of small intestine secretions is _____________
7.5-8.0
The PH of HCL is ______________
0.8
The PH of pancreatic secretion is ______________
8.0-8.5
The daily volume of pancreatic secretion is _______________
1000ml
About ________ml of saliva is secreted every minute while you are awake
0.5
3 functions of saliva
Lubricate food for swallowing
Wash away bacteria and food particles
Contains ptyalin for digestion
Aids in speech
Contains proteins that erase oral bacteria
People salivate more when faced with favourite foods.
True/False
True
___________ determines the type of food a person preferentially seeks
Appetite
Ingestion is determined by
a. Rate of deglutition
b. Hunger
c. Mastication process
d. Appetite
Hunger
Deglutition occurs in 3 stages; ___________, ______________, and _______________
Voluntary stage
Pharyngeal stage
Esophageal stage
Incompetence of the lower esophageal sphincter leading to reflux of food into the esophagus is called ________________
Chalasia
The movement of the smooth muscles of the GIT in an attempt to propel food through is called _____________
Peristalsis
Peristalitic movement is of two types namely; _________________ and _____________
Primary
Secondary
Primary peristalsis propels food from the pharynx to the stomach in how many seconds?
8-10 seconds
The stomach is divided anatomically into __________ and ___________
Body
Antrum
The storage limit of the stomach is _____________
0.8-1.5L
The stomach has two types of tubular glands names ,______________ and _______________
Pyloric glands
Oxyntic glands
Pyloric glands mainly secrete ,___________ and ______________
Mucus
Gastrin
Oxyntic glands are also called __________
Gastric glands
Oxyntic glands are composed of _______________, _____________ and ______________ cells
Chief
Parietal
Mucous Neck cells
Failure of maturation of RBCs due to absence of Vitamin B12 is called ________________
Pernicious anemia
Intrinsic factor is necessary for the digestion of what Vitamin in the ileum?
Vitamin B12 (Cyanocobalamin)
Lack of stomach acid secretion is a condition called _____________
Achlorhydria
The molecular weight of pepsinogen is ____________
42,500
The molecular weight of pepsin is ____________
35000
The Optimum PH of pepsin is _____________
1.8-3.5
Gastrin is secreted in 2 forms
___________ and __________
G34
G17
The gall bladder can hold up to ___________ml of bile
30-60
The liver cells secrete about ______grams of bile salt per day
6
