Human Body Systems and Homeostasis

Body Systems

• Body systems include: digestive, respiratory, circulatory, immune, excretory, and muscular systems.

Digestive System

• Structures: salivary glands, mouth, esophagus, stomach, pancreas, liver, gall bladder, small intestine, appendix, rectum, and anus.
• Functions: digestion, absorption of nutrients.

Homeostasis

• Homeostasis is the dynamic constancy of the internal environment.
• The internal conditions in a living organism fluctuate within limits.
• Homeostasis is essential for life.

Homeostasis 2

• Maintaining internal consistency requires sensors that measure and relay conditions of the internal environment to a control center, which sets the proper value for the condition.
• The control center(brain or spinal cord/ cells of the endocrine)receives information and controls the activity of specific effectors (muscles or glands) to restore the internal environment towards a stable state.

Macromolecules

• Large organic compounds made up of carbon, hydrogen, oxygen, and phosphorus.
• Categories: carbohydrates, lipids, proteins and nucleic acids.
• Many are polymers, long chains of smaller chemical subunits.
• The subunits are joined together through dehydration synthesis and broken down via hydrolysis.

Carbohydrates

• Consist of C, H, and O in a 1:2:1 ratio.
• Function: essential source of short and long-term energy.
• Types: monosaccharides (glucose, fructose, galactose), disaccharides (sucrose, lactose, maltose), polysaccharides (starch, glycogen, cellulose).

Lipids

• Molecules that build cell membranes, steroids and hormones.
• Made of C, H, and O.
• Most are not soluble in water.
• Types: Neutral fats/oils (glycerol and 3 fatty acids), saturated fatty acids (single bonds), unsaturated fatty acids (double bonds), phospholipids (2 fatty acids, 1 phosphate, glycerol), steroids (cholesterol, testosterone, progesterone) and waxes (waterproof).

Proteins

• Main material making up cell parts, carrying out many body functions
• Complex molecules.
• 3D shape determines specific function
• Types: structural (support), storage (source of amino acid), transport (oxygen carrying), contractile.
• Amino acids connect to form polypeptide chains.
• Properties can be disrupted/damaged by environmental changes (denaturation)

Nucleic Acids

• Heredity material.
• Consist of nucleotides (phosphate, sugar and nitrogen base.)
• Examples: DNA (deoxyribonucleic acid), RNA (ribonucleic acid).

Enzymes

• Proteins that act as catalysts, speeding up chemical reactions in the body without being consumed in the process.
• Active site for the substrate, which then changes.
• Factors including temperature, pH and substrate concentration affects enzymes.
• Cofactors and coenzymes assist enzymes with proper function.

Enzyme Lab

• Various virtual lab simulations are available for testing macromolecules.