Digestive System Flashcards
Where does digestion begin?
Mouth
What is the function of the digestive system?
break down food for absorption and distribution of nutrients to the rest of the body
Recite how food is digested
- food is ingested through the mouth where mechanical digestion begins
- Mechanical digestion is any physical breakdown of food–by chewing and grinding food in mouth: Food breaks down into smaller pieces → increases the surface area. Mucus in saliva lubricates the food. Provides the enzymes amylase and lipase. Initiate chemical digestion of starch and lipids
- Chemical digestion is the process where enzymes break down food particles into simple chemicals that can be used by the body
- Next, food is packaged into small parcels called a “bolus” and swallowed (deglutition)
- As the bolus passes through the pharynx, the epiglottis closes the tracheal opening so that food does not enter the respiratory system, and the food passes into the esophagus
- Peristalsis, which is the contractions of muscle, moves the bolus through the gastric sphincter to the stomach.
- Once in the stomach, digestion continues. The stomach is a sac made up of smooth muscles. Stomach muscle contractions mechanically break down food even further and mix with secretions to form a substance called “chyme.”
8.Next, the chyme is pushed into the small intestine - Duodenum: chyme is neutralized by bicarbonate from pancreatic secretions
- The digested material then passes into the cecum and into the large intestine or colon
- The waste from the small intestine is exposed to bacterial fermentation in the colon
What are the three secretions of the stomach?
mucus (lines the stomach), hydrochloric acid (creates the acidic environment), Pepsinogen (converted into pepsin)
What is pepsin?
an enzyme that helps chemically digest proteins in this acidic environment
What hormones are involved in digestion?
Ghrelin, Insulin, Leptin, Glucagon
What does Ghrelin do
Induces hunger
What does leptin do?
Feeling full
What does Insulin do?
Promotes glucose intake by cells
What does glucagon do?
Breaks down stored glycogen
What are the Enzymes involved in digestion?
Protease, lactase
What does bile do in digestion?
Helps neutralize acidic chyme
Where does bile come from?
In the liver
What is the purpose of the gallbladder in digestions?
To emulsify fat
Organs in the digestive system
Salivary glands, mouth, epiglottis, trachea, esophagus, liver, stomach, gallbladder, pancreas, large intestine, small intestine, cecum, appendix, stomach, spleen, duodenum, rectum, anus
Mouth
The oral cavity at the entry to the alimentary canal
Anus
The opening of the rectum from which solid waste is expelled
Gland
an organ that secretes a substance
Chemical (enzymatic) digestion
The breakdown of food by enzymes for absorption
Smooth muscle
Muscle that can be found int he walls of hollow organs, such as the stomach and intestines
Nervous system
A complex system that controls and affects every part of the body in the constant drive to maintain homeostasis
Stomach
The organ between the esophagus and small intestine in which the major portion of digestion occurs
Large Intestine
Compromised of the cecum, colon, rectum and anal canal, it is where vitamins and water are absorbed before feces is stored prior to elimination
Rectum
The last section of the large intestine, ending with the anus
Enzyme
A substance produced by a living thing that acts as a catalyst. A catalyst that speeds up a chemical reaction by lowering the activation energy
Saliva
The clear liquid found in the mouth, also known as spit
Lipase
Pancreatic enzyme that breaks down fat
Lipids
Fatty acids and their derivatives that are insoluble in water
Bolus
A mass of food that has been chewed and swallowed
Peristalsis
A series of muscle contractions that move food through the digestive tract
Chyme
The semifluid mass of partly digested food that moves from the stomach to the small intestine
Pepsin
A stomach enzyme that breaks down proteins
Small intestine
The part of the GI tract between the stomach and large intestine that includes the duodenum, jejunum, and ileum, where digestion and absorption of food occurs
Liver
Organ that produces bile, regulates glycogen storage, and performs other bodily functions
Amino acid
Monomers that make up proteins
Salt
Am chemical compound formed from the reaction of an acid with a base, with at least part of the hydrogen of the acid replaced by a cation
Bacteria
Unicellular organisms that are capable of causing disease
Insulin
A hormone that triggers the influx of glucose into cells, lowering glucose into the blood
Glucagon
A hormone secreted by the pancreas that stimulates its target cells in the liver to convert hepatic glycogen stores into glucose and release glucose into the blood
Nerve
A long bundle of neuronal axons that transmits signals to and from the central nervous system
