Digestion and Excretion in depth Flashcards
(64 cards)
What is the order of organs and sphincters of the digestive tract from ingestion to egestion
oral cavity, pharynx, epiglottis, esophagus, cardiac sphincter, stomach, pyloric sphincter, small intestine, ileocecal sphincter, large intestine, rectum, anal sphincter
Describe the role of sphincters and peristalsis in controlling the movement of material through the digestive system
spincters- close and open to increase or decrease flow
peristalsis- rhythmic movement of smooth muscle organs from contraction ( mechanical digestion)
How is the stomach protected from digestive acid
mucous layer- prevents HCL from irratating stomach wall and creating ulcers.
enzyme is stored in stomach in inactive form (pepsinogen). Only becomes active when Ph drops to around 2 (pepsin). prevents enzyme from digesting stomach wall.
Describe the changes in Ph as food passes through the digestive system
-stomach- Ph drops to 2, turns pepsinogen into pepsin to allow protein digestion
-cyme leaves stomach and is acidic. causes duodenum Ph to drop
-pancreas secrete bicarbonate (basic) into duodenum to raise Ph to around 9
-increase Ph activates trypsinogen into trypsin to allow more protein digestion
Compare and contrast chemical digestion, physical digestion, and absorption
Chemical- breakdown of molecules at the chemical level. The breaking of chemical bonds due to enzymes (stomach acid).
Physical- the breakdown of food into small chunks. The chemical level does not change, but the physical size of the food (chewing).
Absorption- the movement of digested food (monomers such as glucose) into the blood stream. Nutrient absorption happens in the small intestine. Water absorption in the large intestine.
Describe how nutrients are absorbed through villi in the small intestines. How does absorption of lipids differ from the absorption of other nutrients.
villi and microvilli create increased surface area to allow more efficient absorption of nutrients. Nutrients (other than lipids) absorb into capillaries and are carried to the liver to be processed for the body. Lipids are absorbed by lacteals, which transport the absorbed lipids into the lymph system
What is the function of the large intestine
absorption of water and fecal formation
What does bile do, where is it produced stored and released
Bile emulsifies (breaks apart) fat into smaller droplets. it is PHYSICAL DIGESTION. produces in the liver and stored in the gall bladder to secrete bile into the duodenum
What is the duodenum
the first part (of 3) of the small intestine. It is the primary location of chemical digestion in the small intestine. The pancreas and liver excrete enzymes and bile into the duodenum.
Where does absorption take place
in the small intestine
why is it important for the large intestine to absorb water
so the body can maintain homeostasis
most chemical digestion occurs in how many phases
2
What is a thick slippery substance that lines the esophagus
mucus
What does hydrochloric acid do
breakdown food and destroy bacteria in food
What are the two parts of the digestive system
digestive tract and accessory organs
What is the process of food moving in the stomach by peristalsis muscles
mechanical digestion
What are the four stages of food being processed called
ingestion, digestion, absorption, and elimination
What is Digestion
the process that breaks down food into small molecules so they can move through the cell
What process’ are digestion
chemical and mechanical
Mechanical digestion takes place when..
food is chewed churned and mixed
When saliva breaks down the food this kind of digestion is occurring
chemical
What makes chemical digestion occur
enzymes
What is the enzyme in the mouth called
amylase
What is the enzyme in the stomach called
pepsin
