Overview
This lecture provides a comprehensive overview of human anatomy and physiology, explaining the structure and function of major organ systems, their interconnections, and the importance of understanding the body for health and daily life.
Levels of Biological Organization
- The human body is organized into cells, tissues, organs, and organ systems.
- Organs are made of multiple tissue types working together for specific functions.
- Organ systems are groups of organs that coordinate to perform broad physiological tasks.
Major Organ Systems & Functions
- Control systems: nervous, endocrine, reproductive systems coordinate bodily functions and communication.
- Cell maintenance: includes systems like digestive, respiratory, urinary, and immune for homeostasis and defense.
- Support systems: skeletal, muscular, circulatory, and integumentary provide movement, structure, and protection.
- Most organs serve multiple functions and interact across different systems.
Homeostasis and System Interdependence
- Homeostasis is the body's ability to maintain stable internal conditions (e.g. water, temperature, calcium, glucose).
- Multiple organ systems work together for homeostatic regulation; disruptions in one can affect others.
Nervous System Overview
- CNS (brain and spinal cord) processes sensory input and directs motor responses.
- PNS (cranial/spinal nerves) links body to CNS and is divided into autonomic (involuntary) and somatic (voluntary) divisions.
- Neurons transmit signals; classified as sensory (afferent), motor (efferent), or interneurons.
Endocrine System Overview
- Endocrine glands release hormones directly into the bloodstream, affecting distant target cells.
- Hormones regulate growth, metabolism, reproduction, and homeostasis.
- Endocrine and nervous systems both coordinate body responses, but differ in speed and duration.
Reproductive Systems
- Male system: produces and delivers sperm via testes, ducts, and glands.
- Female system: produces eggs (oocytes), supports fertilization, pregnancy, and milk production.
- Gamete production differs: males produce sperm continuously; females have a finite number of oocytes from birth.
Sensory Systems
- Senses are divided into external (sight, hearing, taste, smell, balance) and internal (pain, temperature, pH, etc.).
- Taste and smell rely on chemoreceptors; vision uses photoreceptors; hearing and balance depend on mechanoreceptors; touch uses various specialized receptors.
- Sensory information is integrated in the brain for perception.
Circulatory and Respiratory Systems
- Circulatory system delivers oxygen/nutrients and removes waste; includes heart, vessels, and blood.
- Respiratory system enables gas exchange (Oâ‚‚ in, COâ‚‚ out) through airways and alveoli in the lungs.
Other Major Systems
- Digestive: breaks down food and absorbs nutrients via GI tract and accessory organs.
- Muscular: supports movement through contraction of skeletal, cardiac, and smooth muscle.
- Skeletal: provides structure, protection, movement, and mineral storage; site of blood cell production.
- Integumentary: skin, hair, nails, and glands protect the body and aid in thermoregulation, sensation, and vitamin synthesis.
- Immune: defends against pathogens using innate and adaptive mechanisms.
Key Terms & Definitions
- Homeostasis — Maintenance of stable internal conditions.
- Neuron — Nerve cell transmitting electrical impulses.
- Hormone — Chemical messenger from endocrine glands.
- Gamete — Sex cell (sperm or egg).
- Alveolus — Air sac in lungs for gas exchange.
- Osteocyte — Mature bone cell.
- Melanocyte — Pigment-producing skin cell.
Action Items / Next Steps
- Review diagrams of major organ systems.
- Study tables summarizing organ roles within each system.
- Prepare for discussion on system interconnection and homeostasis with practical examples.