Chapter 1: Introduction to Anatomy & Physiology

Overview of Anatomy and Physiology

Anatomy and physiology are foundational sciences in understanding the structure and function of the human body. Anatomy focuses on the physical structures, while physiology explores how those structures function and interact.

• Anatomy: The study of body structure, including the relationships among body parts.

• Physiology: The study of body function, examining how anatomical structures work together to sustain life.

• Gross/macroscopic anatomy: Study of structures visible to the naked eye.

• Microscopic anatomy: Study of structures requiring magnification, such as cells and tissues.

Homeostasis

Homeostasis is the maintenance of a stable internal environment despite changes in external conditions. It is essential for survival and proper function.

• Variables: Factors that can change (e.g., temperature, pH).

• Receptor: Detects changes in the environment.

• Control center: Processes information and determines response.

• Effector: Carries out the response to restore balance.

• Feedback mechanisms: Negative feedback reduces the effect of the stimulus; positive feedback enhances it.

Orientation and Directional Terms

Directional terms are used to describe the locations of structures relative to other structures or locations in the body.

• Superior: Toward the head or upper part of a structure.

• Inferior: Away from the head or toward the lower part.

• Anterior (ventral): Toward the front of the body.

• Posterior (dorsal): Toward the back of the body.

• Medial: Toward the midline.

• Lateral: Away from the midline.

• Proximal: Closer to the origin of a body part.

• Distal: Farther from the origin.

• Superficial: Toward or at the body surface.

• Deep: Away from the body surface.

Regional Terms

Regional terms specify areas within major body divisions.

• Axial: Head, neck, and trunk.

• Appendicular: Limbs and their attachments.

• Cephalic: Head region (frontal, orbital, nasal, buccal, oral, occipital).

• Thoracic: Chest region (sternal, axillary, mammary).

• Dorsal: Back region (scapular, vertebral, lumbar, sacral).

• Abdominal: Abdomen (umbilical).

• Pelvic: Pelvis (pubic/genital).

• Upper limb: Arm (acromial, brachial, antecubital, olecranal, antebrachial, carpal).

• Manus: Hand (metacarpal, digital).

• Lower limb: Leg (coxal, femoral, patellar, fibular/peroneal).

• Pedal: Foot (tarsal, calcaneal, metatarsal).

Body Planes and Sections

Body planes are imaginary lines used to divide the body for anatomical study.

• Sagittal: Divides body into right and left parts.

  • Midsagittal: Directly along the midline.

  • Parasagittal: Offset from the midline.

• Frontal (coronal): Divides body into anterior and posterior parts.

• Transverse: Divides body into superior and inferior parts.

• Oblique: Cuts made diagonally.

Body Cavities

Body cavities house and protect internal organs.

• Dorsal cavity: Cranial and vertebral cavities.

• Ventral cavity: Thoracic (mediastinum) and abdominopelvic (abdominal, pelvic) cavities.

• Other cavities: Oral, digestive, nasal, orbital, middle ear, synovial.

Abdominopelvic Quadrants and Regions

The abdominopelvic cavity is divided for clinical and anatomical reference.

• Quadrants: Four regions (right upper, left upper, right lower, left lower).

• Regions: Nine regions (e.g., epigastric, umbilical, hypogastric).

Principle of Complementarity of Structure and Function

Structure and function are closely related; changes in structure often result in changes in function.

• Example: Damage to heart valves (structure) impairs blood flow (function).

Chapter 3: Cells and Tissues

Cell Theory and Diversity

Cells are the basic unit of life, and all living organisms are composed of cells. Cells vary widely in structure and function.

• Cell: Smallest unit of life.

• Hydrophilic: Water-loving; describes molecules that interact with water.

• Hydrophobic: Water-fearing; describes molecules that repel water.

Cell Structure and Organelles

Cells contain specialized structures called organelles, each with distinct functions.

• Cytoplasm: Material between the plasma membrane and nucleus; contains cytosol, inclusions, and organelles.

• Mitochondria: Powerhouse of the cell; site of ATP production.

• Endoplasmic reticulum (ER): Rough ER synthesizes proteins; smooth ER synthesizes lipids and detoxifies.

• Golgi apparatus: Modifies, sorts, and packages proteins and lipids.

• Lysosomes: Digestive organelles; break down waste.

• Ribosomes: Sites of protein synthesis.

• Cytoskeleton: Provides structural support; includes microfilaments, intermediate filaments, microtubules.

• Centrioles: Involved in cell division.

• Microvilli: Increase surface area for absorption.

• Nucleus: Contains genetic material (DNA); controls cell activities.

Plasma Membrane Structure and Function

The plasma membrane is a selectively permeable barrier that regulates the movement of substances into and out of the cell.

• Phospholipid bilayer: Double layer of phospholipids with hydrophilic heads and hydrophobic tails.

• Membrane proteins: Integral and peripheral proteins serve as channels, receptors, and enzymes.

• Glycocalyx: Carbohydrate-rich area on cell surface; involved in cell recognition.

Cell Junctions

Cell junctions connect cells and facilitate communication.

• Tight junctions: Prevent leakage between cells.

• Desmosomes: Anchor cells together.

• Gap junctions: Allow passage of ions and small molecules.

Movement of Substances Across the Membrane

Cells transport substances across their membranes using passive and active processes.

• Passive transport: No energy required.

  • Simple diffusion: Movement of molecules from high to low concentration.

  • Facilitated diffusion: Movement via membrane proteins.

  • Osmosis: Diffusion of water across a membrane.

• Active transport: Requires energy (ATP).

  • Protein/solute pump: Moves substances against concentration gradient.

  • Vesicular transport: Endocytosis (phagocytosis, pinocytosis), exocytosis.

Key Equations

• Osmosis: , where is flux, is permeability, and are concentrations.

• Fick's Law of Diffusion: , where is flux, is diffusion coefficient, is concentration gradient.

Tonicity

Tonicity describes the effect of a solution on cell volume.

• Isotonic: No net movement of water; cell volume remains constant.

• Hypertonic: Water moves out; cell shrinks.

• Hypotonic: Water moves in; cell swells.

Histology: Tissues

Tissues are groups of similar cells performing a common function. There are four major tissue types.

• Epithelial tissue: Covers surfaces, lines cavities, forms glands.

  • Simple: Single layer.

  • Stratified: Multiple layers.

  • Squamous: Flat cells.

  • Cuboidal: Cube-shaped cells.

  • Columnar: Tall, column-like cells.

  • Transitional: Changes shape.

  • Glandular: Forms glands (exocrine, endocrine).

• Connective tissue: Supports, protects, binds other tissues.

  • Loose CT: Areolar, adipose, reticular.

  • Dense CT: Regular, irregular, elastic.

  • Cartilage: Hyaline, elastic, fibrocartilage.

  • Bone: Osseous tissue.

  • Blood: Fluid connective tissue.

• Muscle tissue: Produces movement.

  • Skeletal muscle: Voluntary, striated.

  • Cardiac muscle: Involuntary, striated, intercalated discs.

  • Smooth muscle: Involuntary, non-striated.

• Nervous tissue: Transmits electrical signals.

  • Neurons: Conduct impulses.

  • Glial cells: Support neurons.

Developmental Aspects and Tissue Repair

Cells and tissues undergo development and repair throughout life. Tissue repair involves restoring structure and function after injury.

• Processes of tissue repair: Involves inflammation, proliferation, and remodeling.

• Loss of structure: Usually results in loss of function.

Table: Major Tissue Types and Functions

Summary of Key Concepts

• Structure and function are interdependent in anatomy and physiology.

• Homeostasis is maintained by feedback mechanisms.

• Cells are diverse and specialized for various functions.

• Movement of substances across membranes is essential for cell survival.

• Tissues are classified by structure and function; repair is vital for health.