Lesson 12: Nutrition Flashcards
How do we obtain energy via nutrition?
From ingested food that has been mechanically and chemically processed by the body so it can pass through the gastrointestinal tract and enter the bloodstream.
Where does the vascular system carry food molecules through and to before distributing them around the body?
Through the hepatic portal vein and to the liver.
What are food molecules broken down in to after entering the cells?
Carbohydrates, fats and proteins or further used for energy production during exercise.
What is the simplified journey of food through the body? (6)
- First enters via ingestion of food in to the mouth
- Food is then moved along the digestive tract
- Molecules are mechanically prepped for digestion
- It is then chemically digested
- Now ready for absorption into the lymphatic and circulatory systems
- Indigestible/waste products are eliminated via defecation
What does the lymphatic system generally do?
Returns interstitial fluid (excess fluid between cells) back to the bloodstream as to prevent swelling of interstellar spaces.
what is the lymphatic system composed of? (4)
capillaries
collecting vessels
lymph nodes
lymphoid organs
how is lymph fluid different from blood?
it does not carry red blood cells or platelets as these cannot escape via blood-vessel walls
after entering the blood via lymphatic capillaries, where does lymph then circulate?
through the arteries, blood capillaries and veins
what are the 4 functions of the lymphatic system?
- to destroy bacteria and foreign substances
- aid in creation antibodies to destroy bacteria and foreign substances as a specific immune response
- return interstitial fluid to the bloodstream
- prevent excessive accumulation of tissue fluid and filtered proteins by draining them in to highly permeable lymphatic capillaries in the connective tissue
For food to be absorbed by the body, what must it do?
cross cells that line the walls of the gastrointestinal tract as opposed to just passing through
What is the gastrointestinal tract composed of?
mouth pharynx esophagus stomach small intestine large intestine
After entering the mouth, what mechanical process next helps break down the food in to smaller pieces?
chewing
How does saliva ease swallowing?
by blending in to the food and dissolving some of it during chewing.
What does saliva initiate?
carbohydrate digestion
where does swallowed food pass to and via from the mouth?
To the stomach via the pharynx and then esophagus
What is swallowed food first called?
bolus
what is bolus?
ball-like mix of food and saliva
what helps bolus reach the stomach from the esophagus?
waves of peristalses
what are peristalses?
rhythmic contractions of the longitudinal muscles in GI tract that help bolus reach the stomach
after the esophagus, where does bolus go at the top of the stomach?
cardiac sphincter
what does the stomach do to prepare food for entry in to the small intestine?
mechanically grinds the food into chyme and chemically uses specialized stomach cells that produce secretions to break down food particles.
why does the stomach wait for optimal absorption and digestion time before allowing chyme to enter the small intestine?
because the small intestine is the primary site for digestion and absorption, the body has to be careful as to not overwhelm it so that it can do its job well
what energy providing nutrients are absorbed and digested in the small intestine? (6)
carbohydrates fats proteins vitamins minerals water
what is the small intestine further divided in to?
duodenum
jejunum
ileum