Gastro Pharmacology Flashcards
What does the skeletal muscle help with?
Chewing, swallowing and defecation
What does smooth muscle do within the digestive system?
Contractions that mx and move forward contents of the gut
What is phasic smooth muscle?
Action potential induced bursts of contractions, propulsive movements and mixing movements
What is tonic smooth muscle?
Constant low level contraction, tone maintains a steady pressure on contents of gut and prevents the wall from being permanently stretched, this maintains a steady pressure to move food.
What digestive juices are secreted by exocrine glands?
Water, electrolytes, mucus, enzymes and bile salts
Does secretion require energy?
Yes to actively transport raw materials into the cell
Secretion is normally reabsorbed into the blood, True or False?
True
What are the stages in protein digestion?
1) Stomach; pepsinogen is converted to pepsin
2) Pepsin breaks down proteins to peptides,
3) Small intestine, trypsinogen in pancreatic juice is converted to trypsin at basic pH
4) Trypsin breaks down proteins to peptides
5) Peptidases are produced by the small intestine
Peptides broken down to amino acids
6) Active transport of amino acids into epithelial cells in villi,
–> to the blood and liver
What happens to fat absorbed from our diet?
Triglycerides combine with bile salts in the duodenum, fat droplets are formed and large globules are broken, lipids are broken down and absorbed.
What does lipase from the pancreas digest?
Triglycerides which are converted to monoglycerides and fatty acids
What do monoglycerides and fatty acids do?
Diffuse into epithelial cells, recombine and join proteins forming lipoproteins called chylomicrons, they then enter lacteal, and travel to the liver and other areas.
What is starch broken down to?
Pancreatic amylase to maltose
What is glycogen broken down to?
Glucose
What is cellulose broken down to in the gut?
It is NOT broken down by gut enzymes
What is the intrinsic nerve plexuses?
Enteric nervous system, which primarily coordinates local activity in the GI tract.
What types of neurons are associated with the intrinsic nerve plexuses?
*Input neurons (sensory)
*Excitatory and inhibitory output neurons, which modulate motility or secretion of hormones or enzymes
Such as
*Acetylcholine which promotes smooth muscle contraction
*NO and vasoactive intestinal peptide which act together to relax smooth muscle.
What are the extrinsic nerves?
Sympathetic and parasympathetic nerves which influence motility and secretion by modifying activity of intrinsic nerve plexus.
*Sympathetic system slows digestion
*Coordinates activity between different regions of GI tract
How do extrinsic nerves modify activity of the intrinsic nerve plexus?
*Altering secretion of GI hormones
*Directly acting on smooth muscle and glands
What does the Vagus nerve do in the parasympathetic nervous system? *Extrinsic nerves
*Increases smooth muscle motility
*Promotes GI hormone and enzyme secretion
What receptors are their in the GI tract?
*Chemoreceptors
*Mechanoreceptors
*Osmoreceptors
What are the functions of Saliva?
*Digestion - amylase
*Swallowing - moistens food
*Lubrication -mucus
*Antibacterial -lysozymes
*Solvent - stimulate taste buds
*Aids speech - lips and tongue
*Cleanliness of mouth
*Rich in bicarbonate buffers
What pushes food down the oesophagus?
Peristaltic wave