Overview
This lecture introduces the foundational concepts of anatomy and physiology, covering definitions, organization, body directions, planes, cavities, homeostasis, and feedback mechanisms.
Introduction to Anatomy and Physiology
- Anatomy is the study of body structure and the location of body parts.
- Physiology is the study of body function and how structures work.
- Structure and function are linked: "structure dictates function" is the core principle.
- Anatomy is emphasized in lab, physiology in lecture.
Subfields of Anatomy and Physiology
- Systemic anatomy studies organ systems; regional anatomy covers body regions; surface anatomy examines surface markings.
- Gross anatomy focuses on structures visible to the naked eye.
- Microscopic anatomy requires a microscope and includes histology (tissues) and cytology (cells).
- Physiology subfields include neurophysiology (nervous system) and cardiovascular physiology (heart and vessels).
Characteristics of Life
- All living things: made of one or more cells, metabolize, excrete, grow, respond to stimuli, move, and reproduce.
- Metabolism includes anabolic (build up) and catabolic (break down) processes.
- Reproduction includes mitosis (cell division) and meiosis (offspring).
Levels of Structural Organization
- Levels: chemical (atoms, molecules), cellular, tissue, organ, organ system, organism.
Anatomical Position and Directional Terms
- Anatomical position: standing, palms forward, reference for all body descriptions.
- Directional terms: anterior (front), posterior (back), superior (toward head), inferior (away from head), proximal (toward origin), distal (away from origin), medial (toward midline), lateral (away from midline), superficial (surface), deep (internal).
Body Regions and Planes
- Axial region: head, neck, trunk. Appendicular region: limbs.
- Body planes: sagittal (left/right), midsagittal (equal halves), parasagittal (unequal), frontal/coronal (front/back), transverse (top/bottom), oblique (angled).
Body Cavities and Membranes
- Major cavities: dorsal (cranial and spinal), ventral (thoracic and abdominopelvic), separated by the diaphragm.
- Thoracic cavity contains pleural (lungs), mediastinum, and pericardial (heart) cavities.
- Abdominopelvic cavity: divided into regions/quadrants for clinical use.
- Serous membranes (serosa) have parietal (outer) and visceral (inner) layers, secrete serous fluid to reduce organ friction.
Medical Imaging
- X-rays, CT scans, and MRI provide views of body structures in various planes and cavities.
Homeostasis and Feedback Loops
- Homeostasis maintains stable internal conditions (temperature, blood pressure, pH).
- Negative feedback reduces a deviation from a set point (most common, e.g., body temp regulation).
- Positive feedback reinforces a deviation to complete events (e.g., childbirth).
Gradients and Cell Communication
- Gradients (temperature, concentration, pressure) drive body processes.
- Cells communicate via electrical signals (adjacent) and chemical messengers (adjacent or distant).
Key Terms & Definitions
- Anatomy — study of body structure and location.
- Physiology — study of body function.
- Homeostasis — maintenance of stable internal conditions.
- Directional Terms — words used to describe locations on the body.
- Serous Membrane — thin tissue lining body cavities and covering organs.
- Negative Feedback Loop — mechanism that reverses a change to restore balance.
- Positive Feedback Loop — mechanism that amplifies a change until a specific outcome.
- Gradient — difference in physical property (e.g., temperature, pressure) across a space.
Action Items / Next Steps
- Review body regions, planes, and directional terms for identification practice.
- Study diagrams of body cavities and serous membranes.
- Prepare for questions on feedback loops and characteristics of life.