Digestion+absorption Flashcards
What is mastication
Mastication aka chewing is a series of complex neuromuscular events involving several muscle groups which mixes saliva and forms a bolus
In digestion, what are skeletal muscles innervated by?
Motor neurons
What is a reflex
A reflex is an automatic involuntary response to a stimulus
What is the PH of saliva
It is alkaline with a ph lower than 7
What is the function of saliva?
Saliva releases into the mouth and lubricates the food which helps to form a smooth bolus
Where is swallowing controlled?
Medulla/pons area of the brain stem
What type of reflex is vomiting
Protective reflex
What controls vomitting?
Controlled by the vomitting centre in the medulla
Describe the mechanism of vomitting
Increased intra-abdominal pressure
Stomach relaxes to receive intestinal contents
The increase in pressure alongside the relaxation of LOS forces contents into oesophagus
Followed by relaxation of UOS, contents enter into the mouth
What is the myenteric plexus made of
Nerve cells and fibres
What cranial nerves are used in chewing and swallowing?
Nerves V, IX and XII
What is peristalsis
Waves of contraction of smooth muscle to move food along the digestive tract
What is segmentation?
The mixing and churning of food with various enzyme rich intestinal secretions
What does gastrin do?
Increases acid production and motility
When is GIP released?
Released with chyme in duodenum
