More Revision Questions Flashcards
List 2 functions of storage in reference to the alimentary tract
Helps to store the food for enzymatic action
Helps to store indigestible material in the large intestine
Which part of the stomach is endowed with thick muscles and principally responsible for the grinding of the food?
Antrum
Name a paracrine secretion of the alimentary tract that inhibits gastrin-mediated acid secretion and name the cell type that secretes it
Somatostatin
Name 2 endocrine secretions of the alimentary tract and the organs that secrete them
Secretin (small intestine)
Gastrin (stomach)
The alimentary system is described as having its own nervous system. What is the name of this nervous system?
Enteric nervous system
Name an example of a nerve that sends impulses from the gut muscle and mucosa to the spinal cord and signals back to the gut via the enteric nervous system
Splanchnic nerve
Name 2 neurotransmitters that reciprocally the vago-vagal reflex which mediates the motility/secretion and relaxation of the gastric contents
Acetylcholine/SP and VIP
Name the 2 nerve fibres that are intrinsic to the gut and their functions
Auerbach’s (myenteric) plexus: mediate contractions (motor function – innervated by both sympathetic and parasympathetic systems
Meissner’s (submucosal) plexus: intestinal secretions – innervated; receives only parasympathetic input
Name 2 mediators that modulate the reciprocal control of gastric motility
Ach and VIP
The relaxation of the stomach to accommodate food can be mediated by reflexes and 3 types of relaxation can be identified. Name 2 of these
Receptive relaxation– stimulation of pharynx
Adaptive relaxation – presence of food in the stomach (tension; vagal inhibitory fibres: presynaptic release of ACh, followed by VIP/NO, etc. release which help to relax the muscle
Feedback relaxation – CCK (nutrients)
Name one food type that inhibits gastric motor activity
Fats
Name the exocrine secretions of the gut which help in the digestion of:
Starch (carbohydrates)
Fats (dietary lipids)
Starch (carbohydrates): salivary amylase
Fats (dietary lipids): pancreatic lipase
What are the effects of these secretions?
Starch: salivary amylase converts starch to maltose; maltase converts maltose to glucose; sucrase converts to sucrose to fructose and glucose
Lipase converts triglycerides to monoglycerides (glycerol) and fatty acids
Name the secretion and the organ it is secreted from that helps in the emulsification of fats
Bile, gallbladder
Define steatorrhoea
excretion of high amounts of fatty stool, due to lack of fat absorption in small intestine; usually as a consequence of lack of or insufficient release of pancreatic lipase; it is smelly with fat globules in it.
