Digestion and Absorption Flashcards
what are the major organs of digestion?
- mouth
- esophagus
- stomach
- small intestine
- large intestine
- rectum
what are the different sections of the small intestine?
- duodenum
- jujunum
- illium
what are the different sections of the large intestine?
- secum
- ascending colon
- transverse colon
- descending colon
what are the accessory organs in the GI tract?
- salivary glands
- liver
- gallbladder
- pancreas
what is mechanical digestion?
the physical breakdown of food into smaller pieces
what is chemical digestion?
the molecular breakdown of food via enzymes and chemical reactions
what are the functions of the GI tract?
- digestions and absorption of nutrients and fluid
- immune and endocrine functions
- gut-brain axis: large part of nervous system
what is hydrolysis?
chemical reaction breaking down molecules using water
in terms of digestion, what occurs in the mouth?
- food is chewed into a bolus
- epiglottis shuffles food into esophagus
what is a bolus?
a mixture of food and saliva
what is the epiglottis?
an organ that shuttles food from the mouth to the esophagus
in terms of digestion, what occurs in the esophagus?
the bolus travels down the esophagus into the stomach through the lower esophageal sphincter
what is the function of the lower esophageal sphincter?
allows passage of bolus from esophagus to stomach and prevents stomach acid from splashing back into espophagus
in terms of digestion what occurs in the stomach?
- stomach mixes bolus with gastric juice through peristalsis and segmentation
- as the bolus gets mixed it becomes chyme
what is peristalsis?
smooth muscle contraction that move the food through the digestive system
what is segmentation?
muscle contraction that divides the food into smaller sections
in terms of digestion, what occurs in the small intestine?
- chyme enters the intestine through the duodenum, ilium and the jejunum
- site of most absorption of food and fluid
what are the different structures in the small intestine?
- circular folds
- villi
- microvilli
what is the function of the different structures in the small intestine?
to increase surface area
what is an enterocyte?
name of the cell of the small intestine that is the site of absorption
in terms of digestion, what occurs in the large intestine?
chyme enters the large intestine through the secum and travels through the ascending colon, transverse colon, and descending colon
what is the last step of digestion?
exceretion
what is the function of the secum?
serves as the connection between the small and large intestine
what is passive diffusion?
diffusion without the use of ATP; travels down the concentration gradient
what is facilitated diffusion?
diffusion that requires a carrier protein but does not require ATP; travels down the concentration gradient
what is active transport?
diffusion that requires a carrier protein and ATP; travels against concentration gradient
what is endocytosis?
molecules are engulfed by the cell membrane creating a pocket for transport, requires ATP
