Pharmacology Flashcards
What is the movement called of organs running to the anus?
Aboral
What is the movement of organs called running to the mouth?
Oral
What are the organs separated by?
sphincters
What is the role of the mouth and oropharynx?
Chops and lubricates food.
What is the role of the oesophagus?
Propels food to stomach.
What is the role of the stomach?
Stores and churns food
Continues carbohydrate and initiates protein digestion
Regulates delivery of chyme to duodenum
What is the role of the small intestine?
Principle site of digestion and absorption of nutrients
What is the role of the Large intestine?
Reabsorb fluid and electrolytes, stores faecal matter before delivery to rectum.
What is the role of the rectum and anus?
Regulate expulsion of faeces.
What are the accessory structures?
i Salivary glands
ii Pancreas
iii. Liver and gall bladder
What is the overall length of the digestive tract wall?
7-10m
What are the three layers of the tract wall from deep to superficial?
Mucosa
Submucosa
Muscularis externa
Serosa
What makes up the mucosa layer?
Mucous membrane
Lamina propria
Muscularis mucosae
What makes up the submucosa layer?
Connective tissue
larger blood and lymph vessels
glands
submucous plexus
What makes up the muscularis externa?
Circular muscle layer
Myenteric plexus
Longitudinal muscle layer.
What makes up the serosa?
Connective tissue
What are the four main functions of the alimentary canal?
Motility mainly due to smooth muscle
Secretion
Digestion via enzymatic hydrolysis
Absorption- mediated by numerous transport mechanisms
What are the three types of muscle contractions occur for GI motility?
Circular muscle contraction – lumen becomes narrower and longer
Longitudinal muscle contraction – intestine becomes shorter and fatter
Muscularis mucosae contraction – change in absorptive and secretory area of mucosa (folding), mixing activity
How are adjacent smooth muscle cells connected?
gap junctions
How does contraction of smooth muscle cells occur?
As a synchronous wave in a functional unit
What causes and controls electrical activity in the smooth muscle cells?
Caused by:
pacemaker cells
Controlled by:
Intrinsic and extrinsic nerves
Numerous hormones
How does electrical activity spread In the stomach, small, and large intestine ?
In the stomach, small, and large intestine spontaneous electrical activity occurs as slow waves
What is the name of the pacemaker cells?
ii Where are they mainly located?
Interstitial cells of cajal
ii Between circular and longitudinal muscle layers
Depolarizing slow waves do not necessarily result in smooth muscle contraction
true or false?
true
