Homeostasis and Human Body Systems Overview

Homeostasis

Dynamic constancy of the internal environment.

Dynamic

Conditions fluctuate within limits in organisms.

Set Point

Preferred level for internal conditions.

Control Center

Processes information from sensors, often in the brain.

Stimulus

Value determined by the control center.

Effector

Muscles or glands that enact responses.

Response

Action taken by effectors to restore balance.

Negative Feedback Loop

Mechanism correcting deviations from set point.

Sensor

Detects changes disrupting homeostasis.

Water Composition

Body consists of 60% water.

Inorganic Matter

Non-living components like ions and molecules.

Organic Molecules

Contain carbon bonded to hydrogen and others.

Macromolecules

Large organic compounds including carbohydrates and proteins.

Polymers

Long chains of similar chemical subunits.

Dehydration Synthesis

Process forming polymers by removing water.

Hydrolysis

Process breaking down polymers by adding water.

Carbohydrates

Subunits are sugars; store energy.

Monosaccharides

Single simple sugar units.

Disaccharides

Two simple sugars linked together.

Polysaccharides

Long chains of sugar units.

C:H:O Ratio

Carbohydrates contain a 1:2:1 ratio.

Starches

Polymers of glucose for energy storage.

Glycogen

Storage form of glucose in animals.

Polysaccharides

Linked simple sugars for energy storage.

Starch

Polysaccharide for energy storage in plants.

Glycogen

Energy storage polysaccharide in animals.

Cellulose

Structural polysaccharide in plant cell walls.

Lipids

Fats, oils, and phospholipids for energy storage.

Glycerol

Subunit of lipids, combines with fatty acids.

Fatty Acids

Building blocks of lipids, can be saturated or unsaturated.

Saturated Fatty Acids

No double bonds; solid at room temperature.

Unsaturated Fatty Acids

At least one double bond; liquid at room temperature.

Proteins

Polymers of amino acids with diverse functions.

Amino Acids

20 types; building blocks of proteins.

Peptides

Chains of amino acids formed by dehydration synthesis.

Polypeptides

Long chains of amino acids; form proteins.

Nucleic Acids

Polymers of nucleotides; direct cell functions.

DNA

Deoxyribonucleic acid; carries genetic information.

RNA

Ribonucleic acid; involved in protein synthesis.

Vitamins

Organic compounds essential for growth and development.

Minerals

Inorganic compounds aiding in chemical reactions.

Dehydration Synthesis

Water removal to form larger molecules.

Hydrolysis

Water addition to break macromolecules.

Enzymes

Proteins that catalyze biochemical reactions.

Active Site

Part of enzyme binding to substrate.

Catalyst

Speeds up reactions without being consumed.

Active Site

Region where substrate binds on an enzyme.

Substrate

Molecule upon which an enzyme acts.

Temperature Effect

Low temperature reduces enzyme flexibility; high temperature alters shape.

Optimal pH

Ideal pH range for human enzymes is 6-8.

Competitive Inhibitors

Molecules that block substrate binding at active site.

Non-competitive Inhibitors

Molecules that change enzyme shape, inhibiting function.

Mechanical Digestion

Physical breakdown of food into smaller pieces.

Chemical Digestion

Hydrolysis of compounds to break down food chemically.

Gastrin

Hormone released by stomach to produce gastric juices.

Chyme

Partially digested food mixed with gastric juices.

Peristalsis

Wave-like muscle contractions moving food through the digestive tract.

Salivary Amylase

Enzyme in saliva that breaks down starch.

Villi

Small projections in the small intestine that increase absorption surface.

Bicarbonate Ion (HCO3-)

Neutralizes stomach acid in the small intestine.

Liver Functions

Stores glycogen, produces bile, emulsifies lipids.

Gallbladder

Stores bile until needed for fat digestion.

Large Intestine

Absorbs water and salts, forms feces.

Appendix

Vestigial organ, possibly aids immune function.

Rectum

Stores feces before expulsion from the body.

Anus

Controls release of feces via sphincters.

Pepsin

Enzyme that begins protein digestion in the stomach.

Lipase

Enzyme that digests fats in the small intestine.

Triglycerides

Reassembled fats that diffuse into lymph vessels.