Form and function of the GIT Flashcards
what are some of the functions of the GIT
ingestion of food release of fluid and digestive enzymes removal of waste via faeces absorption of nutrients breakdown of food into smaller pieces
how long is the gut
9m
what are the layers of the GIT from outside in
serosa muscularis externae submucosa muscoa villus
what is the role of the serosa
protection from friction as lubrication on surface
what is the role of the muscularis externae
contains longitudinal and circular muscles and the myenteric plexus to shorten and narrow the lumen of the git
what is the submucosa made up of
glands
lymph nodes
nerve and blood supply
what is the mucosa made up of
3 layers
muscularis mucosa
lamina (same as submucosa)
epithelium (villa)
what is the height of villi
0.5 - 1.5 mm
what are the differences in type of cell between crypt and villi
villi have absorptive cells
crypts have secretory cells
what is the cell turnover in the git
3 days
what is the difference between an endocrine and a paracrine mechanism
endocrine - hormone into the blood to then target something else in another location
paracrine - messenger into extracellular space to target neighbouring cells
what are the characteristics of a hormone
have a target induce physiological change travel in the blood be exogenous have an effect even after neural input
what are the two main neural plexi in the git
myenteric and submucosa
how are the myenteric and submucosal plexus regulated
they can work independently of the autonomic nervous system due to pacemaker cells. they talk between each other and can be influenced by hormones and neural input
what innervates the myenteric plexus
parasympathetic system from the vagus and sacral spinal chord
