Human Anatomy Final

mechanical digestion

the breakdown of ingested materials without changing the chemical structure

motility

general term for mixing and moving materials through the GI tract

digestion

breakdown of ingested food into small components

chemical digestion

the process of using enzymes to breakdown complex molecules into smaller molecules

secretion

process of producing and releasing substances that facilitate both digestion and the movement of materials within the GI tract

absorption

membrane transport of digested materials from the lumen of the GI tract into the blood or lymph

elimination

the expulsion of indigestible components through the anal canal

ingestion

introduction of solid and liquid nutrients into the oral cavity

what structures are a part of the GI track?

• pharynx

• esophagus

• large intestine

• anal cavity

• small intestine

• oral cavity

• stomach

what structures are accessory digestive organs?

• liver

• pancreas

• teeth

• tongue

• gallbladder

• salivary glands

peristalsis

sequential contraction of the muscularis within the GI tract that moves like a wave within different regions of the GI tract

mixing

backward and forward motion that blends secretions with ingested material within the GI tract but does not result in directional movement of lumen contents

sphincter

a thickened region of smooth muscle between region of the GI tract that controls the movement of materials into the next section of the GI tract and prevent its backflow

propulsion

the directional movement of materials through the GI tract

short reflex

a local reflex that only involves the enteric nervous system

baroreceptors

sensory receptors that detect stretch

long reflex

a reflex that uses the central nervous system as the integration system

chemoreceptors

sensory receptors that detect the chemical content of materials

secretin

inhibits stomach motility and gastric secretions; increase bicarbonate secretions

gastrin

stimulates stomach motility and increases gastric secretions

cholecystokinin

inhibits stomach motility and secretions; stimulates release of bile and pancreatic enzymes

somatostatin

inhibits the release of acidic secretions

What are the upper GI track organs?

• Pharynx

• Stomach

• Teeth

• Salivary Glands

• Oral Cavity

• Esophagus

• Duodendum

What are the lower GI Track organs?

• Ileum

• Cecum

• Jejunum

• Anal Canal

• Pancreas

• Rectum

• Liver

• Gallbladder

• Colon

liver

produces bile

oral cavity

mastication

large intestine

primarily absorbs water, electrolytes, and vitamins; eliminates undigested materials from the body

small intestine

receives chyme from the stomach; responsible for most of the chemical digestion of chyme; responsible for most of the nutrient absorption

salivary glands

begins the chemical digestion in the mouth

pharynx

carries ingested materials from oral cavity to the esophagus

pancreas

produces several digestive enzymes and the hormones insulin and glucagon

stomach

continued mechanical and chemical digestion of ingested materials; formation of chyme

esophagus

carries ingested materials from pharynx to the stomach

gallbladder

stores bile

parietal cell

secretes intrinsic factor and hydrochloric acid

mucous cell

secretes alkaline mucous

chief cell

secretes pepsinogen and gastric lipase

g-cell

secretes gastin

Order the stomach processes from first to last

• Cephalic Phase

• Gastric Phase

• Intestinal Phase

Order the steps of the cephalic phase from beginning to end.

• thought, smell, sight or taste of food

• nerve signals sent from the cerebral cortex to the hypothalamus and medulla oblongata

• medulla oblongata sends motor information along the vagus nerve

• stomach increases force of contractions and releases secretions

Order the steps of the gastric phase from beginning to end.

• baroreceptors and chemoreceptors in stomach wall are activated

• sensory information sent to the medulla oblongata

• medulla oblongata sends motor information to the stomach using the vagus nerve

• stomach increases force of contractions and release of secretions

Order the steps of the intestinal phase from beginning to end.

• chemoreceptors in the small intestine are activated

• decreased nerve signals to the medulla oblongata 

• the medulla oblongata decreases nerve signals to the stomach

• stomach decreases force of contractions and secretions 

macronutrients

biologic molecules that must be consumed in large quantities; used as fuel for cellular respiration

micronutrients

vitamins and minerals that are consumed in small quantities

nutrients

the biological macromolecules, vitamins, and minerals that the body needs for development, growth, maintenance of physiologic processes, and repair of damaged tissues

nutrition

the study of the means by which living organisms obtain and utilize the nutrients they need to grow and sustain life

nonessential nutrients

substances that can be created by biochemical processes

essential nutrients

substances that must be consumed via diet

Macronutrients include

• Carbohydrates

• Proteins

• Lipids

Micronutrients include

• Vitamins

• Minerals

essential amino acids

a building block of protein that must be obtained from diet

incomplete protein

a protein that does not contain all of the essential amino acids

complete protein

a protein that contains all of the essential amino acids

vitamin K

used in blood clotting

B vitamins

serve as coenzymes for chemical reactions

vitamin E

helps stabilize and prevent damage to cell membranes

nonessential vitamin

a vitamin that can be produced by the body

essential vitamin

a vitamin that must be obtained via diet

vitamin A

used in visual pigments

vitamin D

used in calcium absorption

vitamin C

required for collagen synthesis

zinc

required for protein synthesis and wound healing

iodine

required to produce thyroid hormone

iron

binds oxygen to the hemoglobin molecule of blood

sodium and potassium

maintain membrane potentials, required for action potential propagation

calcium

forms and maintains the skeletal system, required for muscle contractions, required for neurotransmitter release, required for blood clotting

lipids

necessary fro the absorption of vitamins A, D, E and K

carbohydrates

main fuel for ATP production

minerals

inorganic ions

vitamins

required for normal metabolism

proteins

used to make body structures