Anatomy and Physiology: Chapter 1 - Orientation

Introduction

• The first chapter of Anatomy and Physiology is often called "Orientation."
• Key concepts will follow throughout the course, useful for the TEAS exam, nursing program, and nursing career.

Definitions

• Anatomy: Study of human body structure and location.
• Physiology: Study of how the structures function.
• Structure (Anatomy) and function (Physiology) are closely related, known as the dogma of Anatomy and Physiology: structure dictates function.

Types of Anatomy

• Systemic Anatomy: Study of organ systems.
• Regional Anatomy: Study of different body regions.
• Surface Anatomy: Study of surface markings.
• Gross Anatomy: Study of visible structures without a microscope.
• Microscopic Anatomy: Study of structures requiring a microscope.
  • Histology: Study of tissues.
  • Cytology: Study of cells.

Types of Physiology

• Neurophysiology: Studies brain and nervous system.
• Cardiovascular Physiology: Studies heart and blood vessels.

Characteristics of Life

1. Composed of cells.
2. Metabolize (anabolic and catabolic processes).
3. Excrete waste.
4. Grow in size or number.
5. Respond to stimuli.
6. Move internally or externally.
7. Reproduce cells (mitosis) and offspring (meiosis).

Levels of Structural Organization

• Chemical Level: Atoms combine to form molecules.
• Cellular Level: Cells formed from molecules.
• Tissue Level: Cells combine to form tissues.
• Organ Level: Tissues form organs.
• Organ System Level: Organs work together in systems (e.g., skeletal system).
• Organism Level: All systems make up the body.

Anatomical Position

• Standard reference: standing straight, arms at sides, palms forward.
• Left and right refer to the subject's body, not the observer's.

Directional Terms

• Anterior: Front of the body.
• Posterior: Back of the body.
• Superior (Cranial): Toward the head.
• Inferior: Away from the head.
• Proximal: Closer to the point of origin.
• Distal: Farther from the point of origin.
• Medial: Closer to the midline.
• Lateral: Farther from the midline.
• Superficial: Closer to body surface.
• Deep: Farther from body surface.

Body Regions

• Axial Region: Head, neck, trunk.
• Appendicular Region: Limbs.

Planes of Section

• Sagittal Plane: Divides body into left and right.
  • Midsagittal: Equal parts.
  • Parasagittal: Unequal parts.
• Transverse Plane: Divides into superior and inferior.
• Frontal (Coronal) Plane: Divides into anterior and posterior.
• Oblique Plane: Angled division.

Body Cavities

• Dorsal Cavity: Posterior side, includes cranial and spinal cavities.
  • Contains cerebrospinal fluid (CSF).
• Ventral Cavity: Anterior side, includes thoracic and abdominopelvic cavities.
  • Thoracic Cavity: Above diaphragm (lungs and heart).
  • Abdominopelvic Cavity: Below diaphragm (digestive, urinary, reproductive organs).

Serous Membranes

• Thin tissues that secrete lubricating serous fluid.
• Visceral Layer: Inner layer.
• Parietal Layer: Outer layer.
• Types: pleural, pericardial, peritoneal membranes.

Medical Imaging

• X-rays: Use ionized radiation, shows thoracic cavity.
• CT (CAT) Scan: Ionized radiation, transverse view of abdominopelvic region.
• MRI: Magnetic radiation, mid-sagittal view of the brain.

Homeostasis

• Maintenance of stable internal environment.
• Positive and negative feedback loops regulate body state.
  • Negative Feedback Loop: Reduces change; involves receptors, control center, effectors.
  • Positive Feedback Loop: Increases change; e.g., childbirth and oxytocin release.

Communication Between Cells

• Achieved through electrical signals or chemical messengers.
• Example: nerve cells release chemicals to stimulate muscle contraction.

Conclusion

• Structure dictates function and homeostasis is central to understanding anatomy and physiology.
• Gradients and cell communication are key for maintaining homeostasis.