Introduction to Anatomy & Physiology

Overview of Organ Systems

The human body is organized into several organ systems, each composed of specific organs that work together to perform vital functions. Understanding these systems is foundational to the study of anatomy and physiology.

• Organ System: A group of organs that work together to perform a specific function.

• Examples:

  • Digestive System: Mouth, esophagus, stomach, intestines, liver, pancreas.

  • Respiratory System: Nose, trachea, lungs.

  • Circulatory System: Heart, blood vessels.

  • Nervous System: Brain, spinal cord, nerves.

  • Muscular System: Skeletal muscles, cardiac muscle, smooth muscle.

  • Skeletal System: Bones, cartilage, ligaments.

  • Integumentary System: Skin, hair, nails, glands.

Cell Chemistry & Cell Components

Basic Biochemistry and Cellular Structure

Cells are the basic units of life, composed of various organelles and molecules that carry out essential biochemical processes.

• Anabolism: The synthesis of complex molecules from simpler ones; requires energy.

• Catabolism: The breakdown of complex molecules into simpler ones; releases energy.

• ATP (Adenosine Triphosphate): The primary energy carrier in cells.

• Hydrophilic: Molecules that are attracted to water (water-soluble).

• Hydrophobic: Molecules that repel water (not water-soluble).

• pH: A measure of hydrogen ion concentration; scale ranges from 0 (acidic) to 14 (basic).

• Buffer: A substance that minimizes changes in pH.

• Macromolecules:

  • Carbohydrates: Provide energy; e.g., glucose, starch.

  • Lipids: Store energy, form membranes; e.g., fats, oils, phospholipids.

  • Nucleic Acids: Store genetic information; e.g., DNA, RNA.

  • Proteins: Catalyze reactions, structural roles; e.g., enzymes, collagen.

• Enzymes: Biological catalysts that speed up chemical reactions.

Energy & Cell Processes

Cellular Organelles and Functions

Cells contain specialized structures called organelles, each with distinct functions necessary for cell survival and activity.

• Plasma Membrane: Regulates entry and exit of substances; composed of a phospholipid bilayer.

• Mitochondria: Site of ATP production through cellular respiration.

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

• Cytoplasm: Gel-like substance where organelles are suspended.

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

• Cilia: Hair-like projections for movement of substances across cell surface.

• Microvilli: Increase surface area for absorption.

• Vesicle: Membrane-bound sac for transport and storage.

Cell Division: Mitosis and Cytokinesis

• Mitosis: Process of nuclear division resulting in two identical daughter cells.

• Chromosome Behavior: Chromosomes duplicate and segregate to ensure genetic continuity.

• Cytokinesis: Division of the cytoplasm, completing cell division.

Tissues & Histology

Four Basic Tissue Types

Tissues are groups of similar cells that perform specific functions. There are four primary tissue types in the human body.

• Epithelial Tissue: Covers body surfaces and lines cavities; functions include protection, absorption, secretion.

• Connective Tissue: Supports, binds, and protects organs; includes bone, blood, adipose tissue.

• Muscle Tissue: Responsible for movement; types include skeletal, cardiac, and smooth muscle.

• Nervous Tissue: Conducts electrical impulses; found in brain, spinal cord, nerves.

Examples and Locations of Tissue Types

• Nervous Tissue: Brain, spinal cord, peripheral nerves.

• Muscle Tissue:

  • Skeletal Muscle: Attached to bones; voluntary movement.

  • Cardiac Muscle: Heart; involuntary, striated.

  • Smooth Muscle: Walls of hollow organs; involuntary, non-striated.

• Adipose Tissue: Fat storage; under skin, around organs.

• Blood: Circulates in vessels; transports gases, nutrients, wastes.

• Bone: Skeleton; support and protection.

• Epithelial Tissue:

  • Simple Columnar: Lining of digestive tract.

  • Columnar with Cilia: Lining of respiratory tract.

  • Simple Cuboidal: Glands, kidney tubules.

  • Squamous: Lining of blood vessels, alveoli.

Classification of Epithelial Tissue

• Simple Epithelium: Single cell layer; absorption, filtration.

• Stratified Epithelium: Multiple layers; protection.

• Three Main Cell Shapes: Squamous (flat), cuboidal (cube-shaped), columnar (tall).

Integumentary System

Structure of the Skin

The skin is composed of three main layers and associated structures that provide protection, sensation, and regulation.

• Epidermis: Outermost layer; provides barrier function.

• Dermis: Middle layer; contains blood vessels, nerves, glands.

• Hypodermis (Subcutaneous Layer): Deepest layer; stores fat, anchors skin.

• Associated Structures: Hair, sweat glands, sebaceous (oil) glands, arrector pili muscle, blood vessels, nerve fibers.

Layers of the Epidermis

• Stratum Corneum: Outermost, dead keratinized cells.

• Stratum Lucidum: Present in thick skin only (palms, soles).

• Stratum Granulosum: Granular cells, keratin formation.

• Stratum Spinosum: Several layers of keratinocytes.

• Stratum Basale: Deepest, mitotically active layer.

Layers of the Dermis

• Papillary Layer: Superficial, contains dermal papillae.

• Reticular Layer: Deeper, dense irregular connective tissue.

Burn Degrees

Cell Membrane Structure and Transport

Plasma Membrane and Transport Mechanisms

The plasma membrane controls the movement of substances into and out of the cell, maintaining homeostasis through various transport mechanisms.

• Pores and Channels: Allow specific ions and molecules to pass through the membrane.

• Intracellular Fluid: Fluid within cells; high in potassium (K+).

• Extracellular Fluid: Fluid outside cells; high in sodium (Na+).

Types of Membrane Transport

• Simple Diffusion: Movement of molecules from high to low concentration without energy input.

• Facilitated Diffusion: Movement via membrane proteins; no energy required.

• Passive Transport: Includes diffusion and osmosis; does not require energy.

• Active Transport: Movement against concentration gradient; requires energy (ATP).

• Osmosis: Diffusion of water across a semipermeable membrane.

Tonicity

• Hypertonic Solution: Higher solute concentration outside cell; cell shrinks.

• Isotonic Solution: Equal solute concentration; no net water movement.

• Hypotonic Solution: Lower solute concentration outside cell; cell swells.

Vesicular Transport

• Endocytosis: Uptake of materials into the cell via vesicles.

• Exocytosis: Release of materials from the cell via vesicles.

• Phagocytosis: "Cell eating"; engulfing large particles.

• Pinocytosis: "Cell drinking"; uptake of fluids.

Genetic Material and Protein Synthesis

DNA and RNA Types

• DNA (Deoxyribonucleic Acid): Stores genetic information.

• RNA (Ribonucleic Acid): Involved in protein synthesis.

• mRNA (Messenger RNA): Carries genetic code from DNA to ribosomes.

• tRNA (Transfer RNA): Brings amino acids to ribosomes during translation.

• rRNA (Ribosomal RNA): Structural component of ribosomes.

• Chromosomes: Structures composed of DNA and proteins; carry genetic information.

Summary Table: Tissue Types, Functions, and Examples

Additional info: Where original content was brief, academic context and definitions have been added for clarity and completeness.