Digestion in Humans Flashcards
Why do we need food?
It fulfills our daily nutrients, to energize ourselves, increase physical growth, for survival, to repair worn out tissues, grow cells, and produce heat to maintain our body temperature.
What are the 3 main types of nutrients?
Carbohydrates, proteins and fats
What does fat break down into?
fatty acids and glycerol
What is digestion?
process of breaking down large complex molecules into simple, smaller molecules
What are the types of digestion?
mechanical and chemical
What are enzymes?
complex proteins that speed up the rate of chemical reactions.
What suffix do the scientific names for enzymes have?
-ase
What is the optimal temperature for enzymes to react?
45ºC
What are the 2 parts to the digestive system?
True and Accessory
What is the true digestive system?
the tract where food goes through — from the mouth to the anus
What is the accessory digestive system?
the accessory organs to the true digestive system
What organs are in the true digestive system?
mouth, gullet, stomach, small intestine, large intestine, rectum, anus
What organs are in the accessory digestive system?
liver, pancreas, gallbladder
What does the mouth do?
It turns food into mush through mechanical digestion. The salivary glands within it also release salivary amylase.
What does salivary amylase do?
breaks down carbohydrates
What does the tongue do?
it turns food into a ball of mush — called a bolus — then sends it through the gullet (or swallowing)
What are the parts of the teeth?
incisors, canines, bicuspids, molars
What do incisors do?
they cut food
What do canines do?
they stab and rip food
What do bicuspids do?
they crush food
What do molars do?
they grind food
What does the gullet do?
it rolls food with peristaltic movement
What is peristaltic movement?
movement described by the contraction of the gullet to push food into the stomach
What do esophageal sphincters do?
prevent food from going back into the gullet
What is heartburn?
when the lower esophageal sphincter (LES) malfunctions and involuntarily releases stomach acid into the gullet
What does the stomach do?
It mechanically digests the food by contracting. It also produces pepsin and hydrochloric acid to chemically digest food.
What is pepsin?
an enzyme that breaks down proteins
What does hydrochloric acid do?
it contains enzymes that split proteins and also kills bacteria with acid
Where does the body indefinitely store hydrochloric acid?
Nowhere. Hydrochloric acid cannot be stored inside the body (except the stomach for a limited period of time). Hence, HCl is only produced when there is food to digest.
What does the pyloric sphincter do?
prevents food from going back into the stomach from the small intestine
What does the small intestine do?
it digests fats and allows nutrients to diffuse into the bloodstream via diffusion
What are the three main parts of the small intestine?
duodenum, jejunum, ileum
What does villi do?
villi increases surface area for nutrient diffusion and adds digestive secretions
What does the large intestine do?
it stores feces, absorbs vitamins produced by mutually symbiotic bacteria, and reabsorbs water
What do the rectum and anus do?
excrete dried fibers as feces
What does the pancreas do?
makes enzymes and releases them through pancreatic juices into the stomach to assist in digestion
What does the liver do?
produces bile
What does the gallbladder do?
stores and releases bile into the duodenum
What is bile?
a substance that controls the pH of food and emulsifies fats
