Chapter 1: Nutrition (1) Flashcards by isabelle

plays an important role in the utilization of ingested nutrients and water

digestive system

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digestive system: organs of the alimentary and accessory digestive system organs

also called the gastrointestinal tract (GI) or gut

alimentary canal

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digestive system: organs of the alimentary and accessory digestive system organs

is the continuous muscular tube from the mouth to the anus

alimentary canal

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digestive system: organs of the alimentary and accessory digestive system organs

it digests food and absorbs the digested fragments through its lining into the blood

alimentary canal

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organs of the alimentary canal (6)

-mouth
-pharynx
-esophagus
-stomach
-small intestine
-large intestine

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accessory digestive organs (6)

-teeth
-tongue
-gall bladder

large digestive organs
-salivary glands
-liver
-pancreas

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digestive system: organs of the alimentary and accessory digestive system organs

location of teeth and tongue in the accessory digestive organs

mouth or oral cavity

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digestive system: organs of the alimentary and accessory digestive system organs

location of digestive glands and gall bladder in the accessory digestive organs lie outside the

gi tract

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digestive system: organs of the alimentary and accessory digestive system organs

produce a variety of secretions that help break down food

accessory digestive organs

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digestive system

process by which food is broken down into absorbable units

digestion

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digestive system

it is the body’s ingenious way of breaking down foods into nutrients in preparation for absorption

digestion

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digestive tract - anatomy

where digestion begins

mouth

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digestive tract - anatomy (mouth)

act of taking food into the body and swallowing it

ingestion

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digestive tract - anatomy (mouth)

the process of biting and chewing with teeth and jaw

breaks food into small particles that are then exposed to enzymes

fine particles ease swallowing and passage through the git

mastication

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digestive tract - anatomy (mouth)

soft mass of chewed food swallowed at one time

bolus

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food in the mouth stimulates the secretion of salivary glands

the mucus-like saliva performs 3 functions:
1. it mixes with food, _____ dry foods and _____ thicker foods

lubricating; diluting

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food in the mouth stimulates the secretion of salivary glands

the mucus-like saliva performs 3 functions:
2. it provides _____ (a polysaccharide digestive enzyme)

alpha amylase

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food in the mouth stimulates the secretion of salivary glands

the mucus-like saliva performs 3 functions:
2. it provides _____ (a lipid-digestive enzyme)

lipid-digesting enzyme

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food in the mouth stimulates the secretion of salivary glands

the mucus-like saliva performs 3 functions:
3. it dissolves some molecules in food, allowing them to interact with chemoreceptors in the mouth, giving rise to _____

taste sensation

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digestive tract - anatomy (mouth)

mechanically divides food into smaller particles

this action enables the enzymes to readily act on food because of the resulting larger surface area

chewing or mastication

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digestive tract - anatomy

measures about 10 inches long, connects the mouth to the stomach

esophagus

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digestive tract - anatomy (esophagus)

food, lubricated with saliva, is rolled into a small ball (_____) by the tongue to the top of the esophagus

bolus

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digestive tract - anatomy (esophagus)

food is prevented from entering the respiratory tract and lungs by the _____. a small flap at the top of the trachea

epiglottis

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digestive tract - anatomy (esophagus)

the bolus in the esophagus is then propelled to the stomach by _____ (rhythmic contraction and relaxation of the esophageal muscles) and gravity

peristalsis

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digestive tract - anatomy (esophagus) _____ reduces further the size of food particles and mixes them throughly with digestive secretions

peristalsis

digestive tract - anatomy (stomach) gastric secretions that mix with the bolus to form chyme include (1) _____ (secreted from parietal cells)

hydrochloric acid

digestive tract - anatomy (stomach) gastric secretions that mix with the bolus to form chyme include (2) _____ (a hormone secreted by G cells)

gastrin

digestive tract - anatomy (stomach) gastric secretions that mix with the bolus to form chyme include (3) _____ (secreted by the parietal cells), a protein maintained at pH 1.5-1.7

intrinsic factor

3 gastric secretions

hydrochloric acid gastrin intrinsic factor

digestive tract - anatomy (stomach) food in the stomach cause the release of the hormone _____, which in turn stimulates the stomach wall to secrete hydrochloric acid (HCl) and pepsinogen

gastrin

digestive tract - anatomy (stomach) food in the stomach cause the release of the hormone gastrin, which in turn stimulates the stomach wall to secrete _____ and _____

hydrochloric acid (HCl) and pepsinogen

digestive tract - anatomy (stomach) is responsible for the strong acidic condition of the stomach with such an acidic environment, ingested proteins are denatured thus, facilitating their digestion

hydrochloric acid

digestive tract - anatomy (stomach) the inactive pepsinogen is converted to the active enzyme called _____

pepsin

digestive tract - anatomy (stomach) breaks down protein into peptides and amino acids

pepsin

digestive tract - anatomy (stomach) there is only a partial digestion of proteins in the stomach, whereas no digestion of _____ and _____ takes place in the stomach

cho and lipids

digestive tract - anatomy (stomach) the very acidic conditions in the stomach inactivate the polysaccharide-digesting enzyme _____

alpha amylase

digestive tract - anatomy (stomach) to protect the stomach wall from a very acidic content, _____ is secreted forming a protective covering

mucus

digestive tract - anatomy (small intestine) the major digestive and absorptive organ

small intestine

digestive tract - anatomy (small intestine) measuring about 20 ft in length, it is the body's longest organ its 1.5-inch diameter is much smaller than of the large intestine

small intestine

digestive tract - anatomy (small intestine) small intestine extends from the _____ to the ileocecal valve

pyloric sphincter

digestive tract - anatomy (small intestine) small intestine has 3 sections, which connects into the large intestine or colon

duodenum, jejunum, ileum

digestive tract - anatomy (small intestine) circular folds, vili, and microvilli increase the surface area for _____ and ______

digestion and absorption

digestive tract - anatomy (small intestine) the chyme leaving the stomach bypasses the opening from the _____ that receives secretions from the gall bladder and the pancreas

common bile duct

digestive tract - anatomy (small intestine) the liquefied chyme travels the 3 sections of the small intestine

digestive tract - anatomy (small intestine) bile, which is made in the _____ and stored in the gallbladder, is emptied into the small intestine to aid lipid digestion it breaks fat into smaller particles

liver

digestive tract - anatomy (small intestine) bile, which is made in the liver and stored in the _____, is emptied into the small intestine to aid lipid digestion it breaks fat into smaller particles

gallbladder

digestive tract - anatomy (small intestine) bile contains electrolytes, a variety of fatty substances, bile salts, and bile pigments in an aqueous medium

digestive tract - anatomy (small intestine) are emulsifying agents; they disperse fats and form water-soluble micelles, which solubilize the products of fat digestion

bile sats

digestive tract - anatomy (small intestine) released by the small intestine stimulates the gallbladder to contract and the hepatopancreatic sphincter to relax, allowing bile (and pancreatic juice) to enter the duodenum

cholecystokinin

digestive tract - anatomy (small intestine) cholecystokinin released by the small intestine stimulates the _____ to contract and the hepatopancreatic sphincter to relax, allowing bile (and pancreatic juice) to enter the duodenum

gallbladder

digestive tract - anatomy (small intestine) cholecystokinin released by the small intestine stimulates the gallbladder to contract and the _____ to relax, allowing bile (and pancreatic juice) to enter the duodenum

hepatopancreatic sphincter

the presence of chyme in the small intestine stimulates the release of 2 gastrointestinal hormones

secretin and cholecystokinin

these 2 hormones stimulate the pancreas to release its digestive enzymes and sodium bicarbonate, an alkali with neutralizes the acidic chyme the neutralization of the hydrochloric acid in chyme raises the pH levels (pH 5-8) activates the digestive enzymes in the lumen of the small intestine

secretin and cholecystokinin

these 2 hormones stimulate the gallbladder to contract to release the stored bile

secretin and cholecystokinin

large intestine from the small intestine, chyme passes through another sphincter, _____, at the start of the large intestine or colon

ileocecal valve

the subdivisions of the large intestine are (4)

cecum (and appendix), colon, rectum, and anal canal

major functions of the large intestine are

-absorption of water, some electrolytes, vitamins made by enteric bacteria, and defecation

when is the defecation reflex triggered

when feces enter the rectum

digestion - muscular action wavelike muscular contractions of the GIT that push its contents along

peristalsis

digestion - muscular action has the thickest walls and strongest muscles of all the gi tract organs

small intestine

digestion - muscular action composed of circular, longitudinal, and diagonal muscles these 3 sets of muscles work to force the chyme downward, but the pyloric sphincter usually remains tightly closed, preventing the chyme from passing into the duodenum of the small intestine result: chyme is churned and forced down, this the pyloric sphincter, and remains in the stomach

small intestine

digestion - muscular action contraction of circular muscles in small intestine, which mixes the chyme, promoting close contact with the digestive juices and the absorbing cells of the intestinal walls before letting the contents move slowly along

segmentation

digestion - muscular action sphincter muscles periodically open and close, allowing the contents of the GI tract to move along at a controlled pace these are the upper and lower esophageal sphincters, pyloric sphincter, ileocecal valve, tightness of the rectal muscle, and sphincters of the anus

sphincter contractions

the presence of _____ and _____ structures (finger-like projections) increases the absorptive capacity of the small intestine

villi and microvilli

the process by which digested food material passes through the epithelial cells of the GI tract (mainly the small intestine) into the blood or lymph

absorption

absorption - mechanisms some nutrients (water and small lipids) are absorbed by simple diffusion they cross into intestinal cells freely

simple diffusion

absorption - mechanisms some nutrients (water-soluble vitamins) are absorbed by facilitated diffusion they need a specific carrier to transport them from one side of the cell membrane to the other *facilitated diffusion may occur when the carrier changes the cell membrane in such a way that the nutrients can pass thru

facilitated diffusion

absorption - mechanisms some nutrients (glucose and amino acids) must be absorbed actively these nutrients move against a concentration gradient, which requires energy

active transport

absorption - mechanisms process in which the cell membrane engulfs the molecule, forming a sac that separates from the membrane and moves into the cell

endocytosis

absorption - mechanisms nutrients leaving the digestive system via the blood are routed directly to the _____ before being transported to the body's cells

liver

absorption - mechanisms nutrients leaving via the lymphatic system (large fats and fat-soluble vitamins) will enter the _____ but bypass the liver at first

vascular system

supplies oxygen and absorbed nutrients to the lungc

pulmonary circulation

pertains to the sum of reactions and processes involving building up (anabolic) or breaking down (catabolic) of compounds to yield energy and other functional substances

metabolism

is the separation and elimination of waste matter and water from the blood, tissues, or organs these wastes include urine, feces, and perspiration

excretion

organs of excretion (4)

lungs, skin, kidney, intestines

organs of excretion excrete carbon dioxide and water

lungs

organs of excretion secretes mainly water with some salts

skin

organs of excretion excrete water, salts, and nitrogenous substances like urea

kidneys

organs of excretion excrete mineral sats, waste productions in bile, food residues, and some water

intestines

excretion - process a) excretion through the _____ surplus co2 that is continually formed by oxidation of the energy-yielding nutrients in the tissues

lungs

excretion - process b) excretion through the skin water lost through perspiration includes 1. small amounts of _____ products like urea, etc

nitrogenous waste

excretion - process b) excretion through the skin water lost through perspiration includes 2. small amounts of _____ like sodium chloride, etc.

mineral salts

excretion - process c) excretion by the kidneys 2 glandular organs situated at the back of the abdominal cavity on either side of the spinal column these are directly connected by means of a large artery and vein, respectively, with the main arterial and venous trunks of the body these are perfused by a large amount of blood

kidneys

excretion - process c) excretion by the kidneys functional unit of the kidneys

nephron

excretion - process nephrons are made of: -network of capillaries

glomerulus

excretion - process nephrons are made of: double-walled, funnel-like in shape, surrounds the glomerulus

bowman's capsule

excretion - process nephrons are made of: proximal convoluted tubule, henle's loop, and distal convoluted tubule

excretion - process mechanism of excretion by the kidney the semipermeable membrane of the glomerulus allows cleaning of _____ reaching the glomeruli

blood

excretion - process mechanism of excretion by the kidney filtrate includes salts, glucose, amino acids, vitamins, and limited amounts of simple proteins as the filtrate passes thru tubular cells (proximal tubule, distal tubule, and henle's loop), the useful substances such as glucose, amino acids and most of the water are reabsorbed

excretion - process mechanism of excretion by the kidney the ureter collects from the urinary bladder 96% water, waste products made up of urea (about half of the total solids), uric acid, creatinine, and ammonium salts

urine

factors affecting excretion though the kidneys hormones like _____ (ADH) and _____

antidiuretic hormone and aldosterone

factors affecting excretion though the kidneys _____ (substances that stimulate urine flow)

diuretics

factors affecting excretion though the kidneys amount of blood supply to the kidneys

factors affecting excretion though the kidneys - dietary factors _____ and _____ intake requires dilution that increases the sensation of thirst and dehydration of the cells

sodium and sugar

factors affecting excretion though the kidneys - dietary factors excretion of large amounts of urea resulting from a high _____ intake also requires extra water

protein

kidney - functions filtration

kidney - functions balance of

electrolyte and water

kidney - functions acid-base balance

kidney - functions secretes erythropoietin, rennin, prostaglandins, and bradykinins

excretion thru the large intestine the undigested and unabsorbed material expelled thru the anus is known as _____

feces

kidney - functions hormonal breakdown

excretion thru the large intestine feces - composition indigestible, undigested, and unabsorbed _____ residues

food residues

excretion thru the large intestine feces - composition residues from digestive secretions, mucus, and cell debris from the lining of the ______

alimentary tract

excretion thru the large intestine feces - composition bacteria and the products of their action, composes about 1/10 of the feces consisting bacteria (both living and dead)

excretion thru the large intestine feces - composition water that composes 60-70% of ordinary feces

excretion thru the large intestine amount of water ingested

excretion thru the large intestine indigestible substances, chiefly _____ and other complex cho

cellulose

excretion thru the large intestine growth of intestinal bacteria

excretion thru the large intestine laxatives

excretion thru the large intestine types and amount of food taken

excretion thru the large intestine psychological influences such as hurry and nervous stress

excretion process - intestine the large intestine composed of the ascending, descending, and transverse colon allows the undigested/digested food items to: 1. enter the _____ and allows reabsorption of water and electrolytes until feces are formed

ileocecal valve

excretion process - intestine the large intestine composed of the ascending, descending, and transverse colon allows the undigested/digested food items to: 2. defecate thru the _____ and gastrocolic reflex

peristaltic waves

excretion process - intestine the large intestine composed of the ascending, descending, and transverse colon allows the undigested/digested food items to: 3. ferment thru _____ e.g. fibers yiled short chain fatty acids

bacterial action

excretion process - intestine the large intestine composed of the ascending, descending, and transverse colon allows the undigested/digested food items to: other waste products are secreted thru

hair and nails