Functional Anatomy and General Principles Flashcards
(55 cards)
What does the GI tract consist of?
Alimentary tract and associated glandular organs
What is the overall function of the GI tract?
absorb nutrients and water into circulation
excrete waste
What are the 4 major physiological processes?
motility secretion digestion absorption excretion of waste
What is motility required for?
Reduce size of food particles -> increase surface area for chemical digestion by enzymes
Mix food particles with enzymes
Propel food from mouth towards rectum
What causes motility?
contraction of layers of smooth muscle cells in GI tract
What happens in secretion in GI system?
release of enzymes, biological detergents, mucus, ions, and water in GI lumen to aid in digestion and absorption
What is digestion?
process in which ingested macromolecules are converted to smaller, absorb-able molecules (carbs, amino acids, lipids)
What are absorbed through the GI system?
nutrients, water, electrolytes
What are the absorbed particles used for?
energy source
components of biological structures
metabolic pathways
physiologic activities
What are some products from the liver that the GI system excretes?
cholesterol
steroids
drug metabolites
The GI tract is an open/closed environment?
Open to external environment
Does the GI system have an immune function?
Yes. It is the largest immune organ in the body and has immune cells and other non-specific defense mechanisms
What are the major functional segments of the GI system?
Mouth/Pharynx - Esophagus-Stomach-Sm Intestine (DJI)-Lg Intestine- Rectum-Anus
What are the associated glandular organs of the GI system?
Salivary Pancreas Liver Gall Bladder Endocrine Glands/Cells
What are sphincters?
specialized circular muscle structures (smooth or skeletal) that mediate control over the flow of the GI contents between structures
Where is the upper esophageal sphincter?
between pharynx and esophagus
Where is the lower esophageal sphincter?
between esophagus and stomach
Where is the pyloric sphincter?
between the stomach and duodenum
where is the ileocecal sphincter?
between the sm intestine and cecum
Where is the internal and external anal sphincters?
anus
What are the 3 features of the splanchnic circulation?
large blood flow
large reservoir of blood
diverse organs perfused
What are the blood vessels that supply the GI system?
Splanchnic circulation
What are the 3 major arteries supplying the abdominal organs?
Celiac Artery: liver, spleen, stomach
Superior Mesenteric Artery: pancreas, small intestine, proximal colon
Inferior Mesenteric Artery: distal colon
Where does the venous drainage of the GI tract go to?
To the liver via portal vein into the portal circulation