Introduction to Anatomy & Physiology

Definitions and Relationship

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of the body’s structural machinery—how the body parts work and carry out their life-sustaining activities.

• Relationship: Structure determines function; anatomical structures enable specific physiological processes.

• Example: The thin walls of alveoli in the lungs (anatomy) allow for efficient gas exchange (physiology).

Levels of Organization

• Chemical Level: Atoms combine to form molecules.

• Cellular Level: Cells are made up of molecules.

• Tissue Level: Tissues consist of similar types of cells.

• Organ Level: Organs are made up of different types of tissues.

• Organ System Level: Organ systems consist of different organs that work together closely.

• Organismal Level: The human organism is made up of many organ systems.

Body Systems and Their Functions

• Integumentary System: Protection, temperature regulation, sensation.

• Skeletal System: Support, movement, protection, blood cell production.

• Muscular System: Movement, posture, heat production.

• Nervous System: Control, regulation, and coordination of other systems, sensation, memory.

• Endocrine System: Hormone production, internal chemical communication and coordination.

• Cardiovascular System: Transport of nutrients, wastes, gases, and heat.

• Lymphatic System: Immunity, fluid balance.

• Respiratory System: Gas exchange.

• Digestive System: Breakdown and absorption of nutrients, elimination of waste.

• Urinary System: Excretion of wastes, regulation of blood volume and pressure.

• Reproductive System: Production of offspring.

Body Sections and Planes

• Frontal (Coronal) Plane: Divides the body into anterior (front) and posterior (back) parts.

• Sagittal Plane: Divides the body into right and left parts. A midsagittal plane divides it into equal halves.

• Transverse (Horizontal) Plane: Divides the body into superior (upper) and inferior (lower) parts.

Anatomical Position and Its Importance

• Definition: The body is erect, facing forward, arms at the sides with palms facing forward, and feet together.

• Importance: Provides a standard reference for describing locations and directions on the body.

Serous Membranes and Body Cavities

• Serous Membranes: Thin, double-layered membranes that cover organs and line cavities.

• Visceral Layer: Covers the organ.

• Parietal Layer: Lines the cavity wall.

• Pleural Membranes: Surround the lungs.

• Pericardial Membranes: Surround the heart.

• Body Cavities:

  • Cranial Cavity: Contains the brain.

  • Thoracic Cavity: Contains heart and lungs.

  • Abdominopelvic Cavity: Contains digestive, urinary, and reproductive organs.

Palpation, Auscultation, Percussion

• Palpation: Feeling body parts with hands.

• Auscultation: Listening to body sounds (e.g., heart, lungs) with a stethoscope.

• Percussion: Tapping on the body to listen for sounds indicating underlying structures.

Body Regions and Anatomical Landmarks

• Body regions are named areas of the body (e.g., brachial = arm, femoral = thigh).

• Landmarks help describe locations of pain, injury, or procedures.

Relative Positional (Directional) Terms

• Superior (Cranial): Toward the head.

• Inferior (Caudal): Toward the feet.

• Anterior (Ventral): Toward the front.

• Posterior (Dorsal): Toward the back.

• Medial: Toward the midline.

• Lateral: Away from the midline.

• Proximal: Closer to the point of attachment.

• Distal: Farther from the point of attachment.

• Superficial: Toward or at the body surface.

• Deep: Away from the body surface.

Homeostasis and Feedback Mechanisms

• Homeostasis: The maintenance of a stable internal environment.

• Negative Feedback: The response reduces or shuts off the original stimulus (e.g., body temperature regulation).

• Positive Feedback: The response enhances or exaggerates the original stimulus (e.g., blood clotting, labor contractions).

• Feedback Mechanisms: Involve a receptor (detects change), control center (processes information), and effector (carries out response).

Tissues & Histology

Epithelial Tissue

• Definition: Sheets of cells that cover body surfaces or line cavities.

• Functions: Protection, absorption, filtration, excretion, secretion, and sensory reception.

• Characteristics: Polarity (apical and basal surfaces), avascular but innervated, high regenerative capacity.

• Simple Epithelium: Single layer of cells; functions in absorption, secretion, filtration.

• Stratified Epithelium: Multiple layers; protection is a major role.

• Pseudostratified Epithelium: Appears layered but all cells touch the basement membrane.

• Apical Surface: The free surface exposed to the body exterior or cavity.

• Cilia: Hair-like projections that move substances (e.g., in respiratory tract).

• Microvilli: Finger-like extensions that increase surface area for absorption (e.g., in intestines).

Types of Epithelial Tissue

Connective Tissue

• Definition: Supports, protects, and binds other tissues together.

• Characteristics: Cells separated by extracellular matrix; varying degrees of vascularity.

• Types of Fibers:

  • Collagen: Strong, provides tensile strength.

  • Elastic: Stretch and recoil.

  • Reticular: Supportive networks.

• Classification:

  • Connective Tissue Proper: Loose (areolar, adipose, reticular) and dense (regular, irregular).

  • Supporting Connective Tissue: Cartilage (hyaline, elastic, fibrocartilage) and bone.

  • Fluid Connective Tissue: Blood.

• Chondrocytes: Cartilage cells.

• Osteocytes: Bone cells.

Types of Connective Tissue

Muscle Tissue

• Function: Movement of body parts and substances.

• Types:

  • Skeletal Muscle: Voluntary, striated, multinucleated; attached to bones.

  • Cardiac Muscle: Involuntary, striated, branched; found in heart; intercalated discs present.

  • Smooth Muscle: Involuntary, non-striated; found in walls of hollow organs.

Nervous Tissue

• Function: Transmits electrical signals for communication and control.

• Components:

  • Neurons: Conduct nerve impulses.

  • Neuroglia: Support, protect, and nourish neurons.

Lab Identification: Tissue Types

• Be able to identify the following tissues from images:

• Epithelial Tissue: Simple squamous, stratified squamous, simple cuboidal, simple columnar, pseudostratified ciliated columnar, transitional.

• Connective Tissue: Areolar, adipose, reticular, dense regular, dense irregular, hyaline cartilage, elastic cartilage, fibrocartilage, bone, blood.

• Muscle Tissue: Skeletal, smooth, cardiac.

• Nervous Tissue: Neurons and neuroglia.

Additional info: For tissue identification, focus on cell shape, arrangement, presence of fibers, and distinguishing features such as cilia, microvilli, or intercalated discs. Practice with labeled histology images for mastery.