Introduction to Anatomy & Physiology: Foundational Concepts and the Integumentary System

Introduction to Anatomy & Physiology

Overview

Anatomy is the study of the structure of body parts, while physiology focuses on their functions. Understanding both is essential for comprehending how the human body operates as an integrated whole.

Levels of Organization

Hierarchical Structure of the Human Body

• Chemical Level: Atoms and molecules essential for life (e.g., water, proteins, DNA).

• Cellular Level: Cells are the basic structural and functional units of life (e.g., muscle cells, nerve cells).

• Tissue Level: Groups of similar cells performing a common function (e.g., epithelial tissue).

• Organ Level: Structures composed of two or more tissue types working together (e.g., heart, liver).

• Organ System Level: Groups of organs that perform related functions (e.g., digestive system).

• Organismal Level: The complete living being.

Correct order: Chemical → Cellular → Tissue → Organ → Organ System → Organism

The 11 Organ Systems and Major Functions

Overview of Organ Systems

• Integumentary: Protection, temperature regulation, sensation (skin, hair, nails).

• Skeletal: Support, protection, movement, blood cell production (bones, cartilage).

• Muscular: Movement, posture, heat production (muscles).

• Nervous: Rapid internal communication, coordination (brain, spinal cord, nerves).

• Endocrine: Hormone production, regulation of metabolism (glands such as thyroid, pancreas).

• Cardiovascular: Transport of nutrients, gases, wastes (heart, blood vessels).

• Lymphatic: Immunity, fluid balance (lymph nodes, spleen).

• Respiratory: Gas exchange (lungs, trachea).

• Digestive: Breakdown and absorption of nutrients (stomach, intestines).

• Urinary: Waste elimination, water balance (kidneys, bladder).

• Reproductive: Production of offspring (ovaries, testes).

Body Regions: Common and Scientific Names

Key Anatomical Terms

Common Name	Scientific Name
Head	Cephalic
Neck	Cervical
Chest	Thoracic
Arm	Brachial
Forearm	Antebrachial
Thigh	Femoral
Leg	Crural

Characteristics of Life

Essential Features of Living Organisms

• Organization: Structured arrangement of cells and systems.

• Metabolism: All chemical reactions in the body.

• Responsiveness: Ability to detect and respond to stimuli.

• Growth: Increase in size and number of cells.

• Development: Changes in form and function over time.

• Reproduction: Production of new organisms or cells.

Planes & Sections

Dividing the Body for Study

• Sagittal Plane: Divides body into right and left parts.

• Midsagittal Plane: Divides body into equal right and left halves.

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

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

Abdominal Quadrants and Regions

Clinical and Anatomical Divisions

• Quadrants: Right Upper (RUQ), Left Upper (LUQ), Right Lower (RLQ), Left Lower (LLQ)

• Organs in Quadrants: For example, the liver is mainly in the RUQ, the stomach in the LUQ.

Region	Location
Right Hypochondriac	Upper right
Epigastric	Upper middle
Left Hypochondriac	Upper left
Right Lumbar	Middle right
Umbilical	Center
Left Lumbar	Middle left
Right Iliac (Inguinal)	Lower right
Hypogastric	Lower middle
Left Iliac (Inguinal)	Lower left

Directional Terms

Describing Locations and Relationships

• Superior/Inferior: Above/below

• Anterior (Ventral)/Posterior (Dorsal): Front/back

• Medial/Lateral: Toward midline/away from midline

• Proximal/Distal: Closer to/farther from point of attachment

• Superficial/Deep: Toward/away from body surface

Body Cavities and Contents

Major Body Cavities

• Cranial cavity: Contains the brain

• Vertebral cavity: Contains the spinal cord

• Thoracic cavity: Contains heart, lungs

• Abdominopelvic cavity: Contains digestive, urinary, reproductive organs

Types of Microscopes

Microscopy in Anatomy & Physiology

Type	Magnification	Use
Light Microscope	Up to ~1000x	General tissue/cell observation
SEM (Scanning Electron Microscope)	Up to ~100,000x	Surface details, 3D images
TEM (Transmission Electron Microscope)	Up to ~1,000,000x	Internal cell structures

Medical Imaging

Techniques for Visualizing the Body

• X-ray: Bone imaging

• CT (Computed Tomography): Cross-sectional images

• MRI (Magnetic Resonance Imaging): Soft tissue imaging

• Ultrasound: Real-time imaging, often for pregnancy

Cell Chemistry & Cell Components

Types of Cells

• Cells vary in structure and function, including muscle cells, nerve cells, epithelial cells, and more.

Cell Organelles and Functions

• Nucleus: Contains genetic material (DNA)

• Mitochondria: ATP production ("powerhouse")

• Ribosomes: Protein synthesis

• Endoplasmic Reticulum (Rough/Smooth): Protein and lipid synthesis

• Golgi Apparatus: Modifies, sorts, packages proteins

• Lysosomes: Digestion of cellular waste

• Peroxisomes: Breakdown of fatty acids, detoxification

• Centrioles: Cell division

Cell Membrane and Functions

• Selective barrier

• Communication

• Transport of substances

Membrane Transport Mechanisms

• Passive (no energy):

  • Simple diffusion

  • Facilitated diffusion

  • Osmosis

• Active (energy-requiring):

  • Active transport

  • Endocytosis

  • Exocytosis

Example: Sodium-potassium pump uses ATP to move Na+ and K+ against their gradients.

$\text{3 Na}^+ \text{ (out)} + 2 K^+ \text{ (in)} + \text{ATP} \rightarrow \text{Active transport across membrane}$

Cell Attachments

• Desmosomes: Strong adhesion between cells (e.g., skin)

• Tight Junctions: Prevent leakage between cells (e.g., intestines)

• Gap Junctions: Allow communication between cells (e.g., heart)

Cell Division and Mitosis

• Interphase: Cell growth and DNA replication

• Mitosis: Division of nucleus (prophase, metaphase, anaphase, telophase)

• Cytokinesis: Division of cytoplasm

Major events in mitosis:

• Prophase: Chromosomes condense, spindle forms

• Metaphase: Chromosomes align at cell equator

• Anaphase: Sister chromatids separate

• Telophase: Nuclear envelope reforms

Tumors and Cancer

• Risk factors: Genetics, environment, lifestyle

• Treatments: Surgery, chemotherapy, radiation

• Proto-oncogenes: Normal genes that can become cancerous if mutated

Tissues & Histology

The Four Tissue Types

• Epithelial: Covers surfaces, lines cavities, forms glands

• Connective: Supports, binds, protects (e.g., bone, blood, fat)

• Muscle: Movement (skeletal, cardiac, smooth)

• Nervous: Communication (neurons, neuroglia)

Differences: Cell types, matrix, function. Similarities: All composed of cells and extracellular material.

Glands

• Definition: Structures that secrete substances

• Exocrine: Secrete into ducts (e.g., sweat glands)

• Endocrine: Secrete hormones into blood (e.g., thyroid)

Body Membranes

• Mucous: Line cavities open to exterior (e.g., digestive tract)

• Serous: Line closed cavities; secrete serous fluid

• Cutaneous: The skin

• Synovial: Line joint cavities

Serous Membrane Layers: Parietal (lines cavity wall) vs. Visceral (covers organs)

Integumentary System

Functions and Structures

• Protection

• Temperature regulation

• Sensation

• Vitamin D synthesis

• Excretion

Layers of the Skin

• Epidermis: Outer layer, stratified squamous epithelium

• Dermis: Middle layer, connective tissue

• Hypodermis (subcutaneous): Deepest layer, fat storage

Cells of the Skin

• Keratinocytes: Produce keratin

• Melanocytes: Produce melanin (pigment)

• Langerhans cells: Immune defense

• Merkel cells: Sensory receptors

Skin Receptors

• Meissner's corpuscles: Light touch

• Pacinian corpuscles: Deep pressure

• Free nerve endings: Pain, temperature

Skin Markings

• Fingerprints: Unique epidermal ridges

• Cleavage/tension lines: Orientation of collagen fibers

• Flexure lines: Skin folds at joints

Skin Color

• Determined by melanin, carotene, hemoglobin

• Genetics, sun exposure, and health affect color

Hair, Nails, and Glands

• Hair: Protection, sensation; types include vellus, terminal, lanugo

• Nails: Protection, manipulation

• Glands: Sebaceous (oil), sudoriferous (sweat), ceruminous (earwax)

Types of Exocrine Glands

Type	Secretion Method	Example
Merocrine	Secrete via exocytosis	Sweat glands
Apocrine	Part of cell pinched off	Mammary glands
Holocrine	Entire cell disintegrates	Sebaceous glands

Types of Burns

• First-degree: Epidermis only

• Second-degree: Epidermis and part of dermis

• Third-degree: Full thickness (epidermis, dermis, hypodermis)

Aging and the Skin

• Thinning of epidermis and dermis

• Decreased collagen and elasticity

• Slower healing

• Increased risk of injury and infection