Introduction and Organizing Principles

Anatomy and Physiology Relationship

Anatomy is the study of the structure of body parts, while physiology is the study of how those parts function. The principle "structure dictates function" means that the form of a body part is directly related to its job in the body.

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

Structural Hierarchy / Levels of Biological Organization

Biological systems are organized in a hierarchy from simplest to most complex:

• Chemical level: Atoms and molecules (e.g., water, proteins)

• Cellular level: Cells and their organelles

• Tissue level: Groups of similar cells performing a common function

• Organ level: Structures composed of at least two tissue types

• Organ system level: Organs working together for a common purpose

• Organismal level: The living human being

Characteristics of Life

• Organization

• Metabolism

• Responsiveness

• Growth

• Differentiation

• Reproduction

• Homeostasis

Basics of Tissues, Organs, and Organ Systems

• Tissues: Groups of similar cells with a common function (e.g., muscle tissue).

• Organs: Structures composed of at least two tissue types (e.g., heart, liver).

• Organ Systems: Groups of organs that work together (e.g., digestive system).

Mapping the Human Body

• Anatomical Position: Body standing upright, facing forward, arms at sides, palms facing forward.

• Directional Terms: Used to describe locations (e.g., superior, inferior, anterior, posterior, medial, lateral).

• Regional Terms: Specific areas (e.g., brachial for arm, femoral for thigh).

• Quadrants/Regions: Abdomen divided into four quadrants or nine regions to locate organs (e.g., liver in right upper quadrant).

Homeostatic Set Points and Feedback Mechanisms

• Homeostasis: Maintenance of a stable internal environment.

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

• Positive Feedback: Response enhances original stimulus (e.g., blood clotting, labor contractions).

Intracellular vs. Extracellular Fluid

• Intracellular fluid (ICF): Fluid within cells.

• Extracellular fluid (ECF): Fluid outside cells (includes plasma and interstitial fluid).

Cell Structure and Function

Cell Theory

• All living things are composed of cells.

• Cells are the basic unit of structure and function.

• All cells arise from pre-existing cells.

Biomolecules

• Carbohydrates: Energy source and structural roles.

• Lipids: Energy storage, membrane structure (phospholipid bilayer).

• Proteins: Structure, enzymes, transport, signaling. Organization: primary, secondary, tertiary, quaternary structure.

• Nucleic Acids: DNA and RNA, genetic information storage and transfer.

Cellular Membrane

• Components: Phospholipid bilayer, proteins, cholesterol, carbohydrates.

• Membrane Fluidity: Regulated by cholesterol and fatty acid composition.

Protein Organization

• Primary: Sequence of amino acids.

• Secondary: Alpha helices and beta sheets.

• Tertiary: 3D folding of a single polypeptide.

• Quaternary: Multiple polypeptides forming a functional protein.

• Example: Sickle cell disease results from a single amino acid change in hemoglobin, altering its structure and function.

Genetic Material

• DNA: Stores genetic information.

• RNA: Transfers genetic code from DNA to ribosomes for protein synthesis.

• mRNA: Messenger RNA, carries code from DNA to ribosome.

• tRNA: Transfer RNA, brings amino acids to ribosome during translation.

Protein Processing and Trafficking

• Proteins are synthesized in the ribosome, processed in the endoplasmic reticulum and Golgi apparatus, and transported to their destinations.

Exocytosis

• Process by which cells expel materials in vesicles that fuse with the plasma membrane.

Molecular Transport

• Passive Transport: No energy required (diffusion, osmosis, facilitated diffusion).

• Active Transport: Requires energy (primary and secondary active transport, endocytosis, exocytosis).

Cell Signaling

• Autocrine: Cell targets itself.

• Paracrine: Cell targets nearby cells.

• Endocrine: Cell targets distant cells via bloodstream.

Cell Junctions

• Desmosomes: Anchor cells together.

• Tight Junctions: Prevent passage between cells.

• Gap Junctions: Allow communication between cells.

Cell to Extracellular Matrix Interactions

• Cells interact with the extracellular matrix for support, signaling, and anchoring.

Cell Cycle

• Interphase: G1 (growth), S (DNA synthesis), G2 (preparation for mitosis).

• Mitosis: Prophase, metaphase, anaphase, telophase, cytokinesis.

Basics of Cellular Organelles

• Nucleus: Contains DNA.

• Mitochondria: ATP production.

• Endoplasmic Reticulum: Protein and lipid synthesis.

• Golgi Apparatus: Modifies and packages proteins.

• Lysosomes: Digestion of cellular waste.

• Peroxisomes: Breakdown of fatty acids and toxins.

Histology

Epithelial Tissues

• Types: Simple/stratified squamous, cuboidal, columnar, pseudostratified, transitional.

• Locations: Skin, lining of GI tract, respiratory tract, glands.

• Functions: Protection, absorption, secretion, filtration.

Connective Tissues

• Types: Loose (areolar, adipose, reticular), dense (regular, irregular), cartilage, bone, blood.

• Locations: Tendons, ligaments, fat, bone, blood.

• Functions: Support, protection, transport, insulation.

Muscle Tissues

• Types: Skeletal, cardiac, smooth.

• Locations: Attached to bones, heart, walls of hollow organs.

• Functions: Movement, posture, heat production.

Nervous Tissue

• Types: Neurons and neuroglia.

• Locations: Brain, spinal cord, nerves.

• Functions: Transmit electrical impulses, support neurons.

Tissue Injury and Repair

• Involves inflammation, regeneration, and fibrosis (scar formation).

Life and Death of Cells and Tissues

• Cells undergo apoptosis (programmed cell death) or necrosis (uncontrolled cell death).

Integumentary System

Basic Anatomy and Functions

• Composed of skin, hair, nails, glands.

• Functions: Protection, temperature regulation, sensation, vitamin D synthesis, excretion.

Epidermis

• Cell Types: Keratinocytes, melanocytes, Langerhans cells, Merkel cells.

• Cell Layers: Stratum basale, spinosum, granulosum, lucidum (in thick skin), corneum.

• Pigmentation: Determined by melanin, carotene, hemoglobin.

• Sensory Structures: Free nerve endings, tactile discs.

• Vitamin D Synthesis: UV light converts 7-dehydrocholesterol to vitamin D3 in the skin.

Dermis

• Layers: Papillary (areolar connective tissue), reticular (dense irregular connective tissue).

• Functions: Provides strength, elasticity, houses blood vessels and nerves.

Hypodermis

• Also called subcutaneous layer; composed mainly of adipose tissue for insulation and energy storage.

Accessory Structures

• Hair Follicle & Shaft: Produces hair for protection and sensation.

• Hair Color: Determined by type and amount of melanin.

• Hair Texture: Influenced by follicle shape and genetics.

• Nails: Protect distal phalanges, aid in grasping.

• Arrector Pili Muscles: Cause hair to stand up (goosebumps) in response to cold or fear.

• Glands: Sebaceous (oil) and sudoriferous (sweat) glands for lubrication and thermoregulation.

Effects of Aging on the Skin

• Thinning, decreased elasticity, reduced gland activity, increased risk of injury and infection.

Interconnection with Other Systems

• Skin interacts with immune, nervous, circulatory, and endocrine systems.

Skin Cancer Types