nutrition and digestion

78 terms by karepare 

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BMI

Body Mass Index is used to assess healthy body weight. A person's weight in kilograms divided by the square of height in meters.

macronutrients

A chemical substance that an organism must obtain in relatively large amounts. For example carbohydrates, fats & proteins.

micronutrients

Nutrients required in small or trace amounts. Some examples are vitamins and minerals.

carbohydrates

molecules made of C, H, and O in a 1:2:1 ratio; a source of energy for the body.

monosaccharide

single sugar (ex. glucose)

disaccharide

double sugar (ex. sucrose)

polysaccharide

a complex molecule composed of three or more monosaccharides (ex. starch)

dehydration synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

hydrolysis

a chemical reaction in which water reacts with a compound to produce other compounds

glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals.

cellulose

polysaccharide consisting of glucose monomers that reinforces plant-cell walls; indigestable by humans

fat

molecules made of C, H, and O in no set ratio; a source of energy for the body;building materials for cell membranes & hormones, insulate from cold, protect vital organs from injury

saturated fats

solid at room temperature; all bonding sites on the carbon atom are occupied by hydrogen ("bad" fat)

unsaturated fats

have double bonds; "good" fats; poly unsaturated fats (many double bonds); mono unsaturated fats (1 double bond)

cholesterol

A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids. Too much can lead to life threatening problems.

proteins

contains carbon, hydrogen, oxygen, and nitrogen; are a source of energy; needed by tissue for repair and growth; can be enzymes, antibodies, hormones

amino acid

organic compounds containing an amino group and a carboxylic acid group; are the basic building block of proteins; twenty different types, eight of which the body cannot make and we must get from the diet

peptides

chain of amino acids held together by peptide bonds

minerals

inorganic cpds. needed in small amounts for some chemical reactions, building of bones, hemoglobin, hormines, enzymes & vitamins

vitamins

compounds that help regulate many vital body processes, including the digestion, absorption, and metabolism of other nutrients. Required in small amounts. Some are fat soluble and some are water soluble.

anorexia nervosa

an eating disorder in which a normal-weight person diets and becomes significantly underweight, yet, still feeling fat, continues to starve

bulimia

eating disorder characterized by excessive eating followed by purging

mechanical digestion

The process through which your food is physical broken down into smaller, more manageable pieces. The result is a physical change.

papillae

small rough elevations on tongue containing taste buds

uvula

structure hanging from the middle of the back edge of the soft palate prevents food from entering the pharynx when we swallow.

salivary glands

three pairs of exocrine glands in the mouth that secrete saliva; involved in chemical digestion and lubricates food

parotid gland

largest salivary gland, found below & in front of each ear

sublingual gland

smallest salivary gland, found beneath the floor of the mouth, behind the incisor

submaxillary gland

found below & behind the sublinguals

bolus

ball of food formed by the tongue, for ease of movement through the esophagus

pharynx

throat; passageway for food to the esophagus and air to the larynx

epiglottis

flap of tissue that covers the trachea when you swallow to prevent food from entering the lungs

esophagus

a muscular tube that connects the mouth to the stomach

peristalsis

wave-like muscle contractions of the alimentary tract that moves food along

serosa

the delicate outer layer of tissue of most organs, that holds esophagus in place

stomach

large, J-shaped, muscular sac that continues the mechanical and chemical digestion of food

gastric glands

found in the stomach and secrete gastric juices

gastric juice

digestive secretions of the stomach glands consisting chiefly of hydrochloric acid and mucin and the enzymes pepsin and rennin and lipase

cardiac sphincter

the ring-like muscle between the esophagus and stomach that controls food flow; will prevent flow of food and acids back into the esophagus

pyloric sphincter

ring of muscle that controls the opening between the stomach and the duodenum;

rugae

folds in the lining of the stomach that expands surface area

pepsin

enzyme that breaks down proteins in the stomach

pepsinogen

released in stomach, reacts with HCl to create pepsin

rennin

chemical found in baby's stomach and is used to slow down the movement of milk through the digestive system to give time for absorption of nutrients

ulcers

open sores in the lining of the stomach or the small intestine generally associated with some kind of irritant or bacterial infection which results in the loss of the mucus laryer. Allows HCl to create a hole in the stomach.

villi

Small fingerlike projections on the walls of the small intestines that increase surface area

microvilli

Tiny hair-like projections of the cytoplasmic membrane located only in the small intestine to facilitate absorption by increasing surface area.

lacteal

a small vessel in the center of the villi that transports the products of fat digestion to the circulatory system

duodenum

first part of the sm. intestine; .5 m long; involved in chemical digestion

jejunem

second part of the sm. intestine; 2.5 m long; continues some chemical digestion but mostly involved in absorption of nutrients

ileum

third part of the sm. intestine; 3 m long; contains fewer & smaller villi for the continuation of absorption of nutrients

large intestine

1.5 m long & greater diameter than the sm. intestine; involved in water (& some mineral) reabsorption; forms and stores feces for elimination; vit. B-12 & K are produced here

ileocaecal valve

A sphincter muscle situated at the junction of the small intestine (ileum) and the large intestine

caecum

sac located near the junction of the ileum and lg. intestine

appendix

a vestigial process that extends from the lower end of the cecum and that resembles a small pouch; no role in digestion but might help to fight infections

rectum

A short tube at the end of the large intestine where waste material is compressed into a solid form before being eliminated

anus

opening of the rectum to the outside of the body control the timing of elimination (to some extent) by anal sphincters

ulcerative colitis

inflammation of the lining of the rectum & large intestine

Crohn's disease

inflammation can be any where in the G. I. tract, but is mostly in the small intestine

constipation

irregular and infrequent or difficult evacuation of the bowels; can have many causes, but often not enough fiber in the diet.

liver

divided into 2 large lobes; produces bile, breaks down old red bl. cells and a.a., stores excess chemicals, detoxifies various poisons

bile

A substance produced by the liver that breaks up fat particles and is stored in the gallbladder.

cirrhosis

chronic disease characterized by scarring of liver tissue, most often caused by alcoholism or a nutritional deficiency.

alcoholic hepatitis

inflammations of the liver leading to decreased ability to break down toxins. Some symptoms are nausea, vomiting, abdominal pain, jaundice.

gallbladder

a muscular sac attached to the liver that secretes bile and stores it until needed for digestion

cholecystokinin

hormone the small intestine secretes to stimulate release of pancreatic juice from pancreas and bile from gallbladder

gallstones

small hard particles made of cholesterol which form and collect in the gall bladder --may block the bile duct causing pain and discomfort, may treated by surgical removal of the gall bladder

pancreas

located partially behind the stomach in the abdomen, and it functions as both an endocrine and exocrine gland. It produces digestive enzymes as well as insulin and glucagon.

secretin

A hormone secreted by the small intestine in response to low pH (e.g., from stomach acid). It promotes the release of bicarbonate from the pancreas to act as a buffer.

cellulase

made by microbes in intestine to break down cellulose in GI tract

ruminants

An animal, such as a cow or sheep, with an elaborate, multicompartmentalized stomach specialized for an herbivorous diet.

crop

a pouch in many birds and some lower animals that resembles a stomach for storage and preliminary maceration of food

gizzard

thick-walled muscular pouch below the crop in many birds and other organisms, containing gravel to mechanically grind food

prostomium

liplike covering over mouth; pushes soil into mouth

intracellular digestion

process in which food is digested inside cells

extracellular digestion

digestion occurs outside the cells; eg. in alimentary canals

xylem

the vascular tissue through which water and nutrients move upward in some plants

phloem

vascular tissue responsible for the transport of nutrients and the carbohydrates produced by photosynthesis

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