Fundamentals of Human Biology
1. Levels of Organization
Atoms: Chemical elements that make up living organisms.
Molecules: Components from which cells build structures, reaching cells from the blood.
Cells: The basic unit of living things, responsible for nourishment, waste elimination, interaction, and reproduction.
Tissue: A group of specialized cells combined for a particular function.
Organ: Composed of different tissues with a specific function.
Apparatus: Association of organs working together for a specific function.
Homeostasis: Mechanisms coordinating the operation of equipment, systems, and organs.
2. Life Maintenance
Essential for life maintenance:
- Nutrients
- Oxygen
- Water
- Constant internal environment
- Cooperation of all systems
3. Cell Structure
- Plasma membrane
- Cytoplasm
- Nucleus
Cellular metabolism: Set of biochemical reactions in the cell.
4. Nucleus
Contains information for cell operation and reproduction.
Genetic information: Instructions for protein manufacturing.
5. DNA Forms
DNA exists as chromatin (resting state) and chromosomes (reproductive state). Humans have 46 chromosomes (44 autosomes and 2 sex chromosomes).
6. Cell Organelles
- Endoplasmic reticulum: Stores and transports proteins.
- Ribosomes: Produce proteins from genetic information.
- Centriole: Enables organelle movement and cell shape.
- Lysosomes: Act as the cell’s digestive system.
- Golgi apparatus: Modifies and transports lipids and proteins.
- Nucleus: Directs cellular activity.
- Cytoplasm: Site of most cellular activities.
- Mitochondria: Produces energy from glucose.
- Plasma membrane: Defines the cell and its contact with the outside.
- Chloroplasts: Perform photosynthesis.
- Vacuole: Stores substances.
- Cell wall: Provides security and substance exchange.
7. Epithelial Tissue
Responsible for protection, absorption, secretion, filtration, and excretion.
- Cover: Lines the body and internal cavities (simple and stratified).
- Glandular: Forms glands (endocrine, exocrine, mixed).
8. Connective Tissue
Maintains structure, joins tissues, and protects organs.
- Lax: Surrounds and protects organs.
- Dense: Tough due to collagen fibers.
- Cartilage: Gelatinous matrix with collagen and elastic fibers.
- Bone: Hard matrix with mineral salts.
- Blood: Liquid matrix with plasma and blood cells.
9. Nervous Tissue
Consists of neurons and glial cells.
- Neuron: Functional unit for receiving and conducting information.
- Glial cells: Support and protect neurons (astrocytes, microglia, Schwann cells).
10. Muscle Tissue
Changes shape and length to produce movement.
- Striated: Red muscle fibers for voluntary movement.
- Smooth: Pale pink fibers for involuntary movement.
- Cardiac: Branched red fibers for rhythmic heart contractions.
11. Body Systems
- Nutrition: Respiratory, digestive, circulatory, and excretory systems.
- Reproduction: Reproductive system.
- Value: Skeletal, muscular, nervous, integumentary, endocrine, and immune systems.
Specific functions of each system are detailed in the original text.