Digestive system

What is bilirubin?

is produced during degradation of hemoglobin. It is the major excretory product in the feces.

Where is chyme converted to feces?

large intestines

List the layers of the alimentary canal from lumen to the outside.

lumen, mucosa, submucosa, muscularis, serosa

Mucosa function

luminal surface of the digestive tract

Muscularis

major smooth muscle coat of the digestive tract

Distinguish between chemical and mechanical digestion.

Mechanical digestion begins in the mouth as the food is chewed. Chemical digestion involves breaking down the food into simpler nutrients that can be used by the cells.

What is the benefit of the bacteria in the large intestine?

absorption of vitamins

What is the purpose of saliva?

amylase begins digestion of carbohydrates moistens and lubricates food for swallowing antibacterial action dissolves molecules that stimulate taste keeps lips and tongue moist during speech

what are vitamins?

an organic compound and a vital nutrient that an organism requires in limited amounts

Why is cellulose considered to be fiber?

because it can't be broken down,

What is bile made up of? What is its function?

bile salts, cholesterol, lecithin and bilirubin; increases the absorption of fat and fat-soluble substances

What is the difference between bolus and chyme?

bolus is a ball of food that was chewed and swallowed, chyme is the bolus with secretions mixed in it

List the functions of the stomach.

break down and digest food in order to extract necessary nutrients from what you have eaten

What are the parts of the large intestine?

cecum, colon, rectum

What is another term for: swallowing?

deglutition

Provide two structures for each and how they act to contribute to this function Secretion

esophagus (esophageal secretion mucus is protective) and pancreas (secretes enzymes and aqueous alkaline solution)

What is the main energy source of the body?

glucose

What happens during the swallowing reflex?

initiated by touch receptors in the pharynx as a bolus of food is pushed to the back of the mouth by the tongue, or by stimulation of the palate

What is the job of the stomach besides storage of food and mechanical break down of food?

initiates protein digestion and denatures proteins

What is peristalsis?

involuntary constriction and relaxation of the muscles

Distinguish between villi and microvilli. Where are they?

Microvilli can be found in many cell membranes while the villi can only be found in the intestinal wall. The villi are larger than microvilli. The villi act to increase the absorption rate of the intestines while the microvilli have more functions besides absorption of cell nutrients

What are the three sections of the small intestine?

duodenum, jejunum, ileum

another term for vomiting

emesis

another terms for chewing

mastication

Provide two structures for each and how they act to contribute to this function Motility

mouth (food enters the digestive system through the mouth where it is chewed and mixed with saliva) and tongue (propels the bolus to the rear of the throat, to initiate swallowing reflex)

define absorption

movement of a substance, such as a liquid or solute, across a cell membrane by means of diffusion or osmosis

What does the esophagus secrete?

mucus

What cells of the stomach secrete HCl?

parietal cells

What determines the rate of gastric emptying?

pressure generated by the antrum against pylorus resistance

What does bile do? What does it do with bilirubin?

provide emulsification to aid fat digestion form water-soluble micelles to aid fat absorption

Describe the function of mucus

provides as a protective coating

parietal cells

secrete HCL which sterilizes the food in the stomach, prevents harmful bacteria from entering the stomach, and triggers the release of enzymes

chief cells

secrete pepsinogen which is a proteolytic enzyme responsible for the digestion of proteins

mucous cells

secretes an alkaline mucus that protects against shear stress and acid

function of pepsin

starts protein digestion in the stomach

What is hydrolysis?

the chemical breakdown of a compound due to reaction with water

Where does digestion actually begin?

the mouth

Define digestion

the process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body

What are the functions of the large intestine?

to absorb water from the remaining indigestible food matter and transmit the useless waste material from the body

How many teeth does an adult human have?

32 teeth

function of hydrochloric acid

Activates pepsinogen to active enzyme pepsin. Provides acid medium for optimal pepsin activity. Aids in breakdown of connective tissue and muscle fibers. Denatures protein. Kills most of microorganisms ingested with food.

What are the factors in control of food intake?

Adult animals (including humans) tend to maintain a relatively constant weight known as their "set weight"; starvation or force feeding

What are the functions of the pancreas?

Produces important enzymes and hormones that help break down foods.

What are nutrients?

a substance that provides nourishment essential for growth and the maintenance of life

what are minerals?

a solid inorganic substance of natural occurrence

four layers of the wall of the digestive system

mucosa, submucosa, muscular, and serosa

List the structures of the digestive tract as food passes through it.

oral cavity, pharynx, esophagus, stomach, small intestine, liver, gall bladder, pancreas, large intestine, cecum, colon, rectum, anus

Serosa

outer connective tissue covering

What controls the secretion of saliva?

salivary center

G cells

secretes hormone gastrin which stimulates the release of gastric gas

What type of motility is done by the small intestine?

segmentation

Provide two structures for each and how they act to contribute to this function Absorption

small intestine (end products of carbohydrates and proteins are absorbed into the bloodstream) and large intestine (remaining salt and water converts the contents into feces)

Where is chyme created?

stomach

What are rugae?

stomach folds

Submucosa function

thick layer of connective tissue that provides distensibility and elastic