Exam 1 Review: Human Body Orientation, Chemistry, Cells, and Tissues

Chapter 1: The Human Body: An Orientation

Definitions and Subdivisions of Anatomy and Physiology

• Anatomy: The scientific study of body structures and their relationships.

• Physiology: The study of how body parts function together to support life, focusing on mechanisms that maintain homeostasis.

• Subdivisions of Anatomy:

  • Gross Anatomy: Structures visible to the naked eye (e.g., organs).

  • Microscopic Anatomy: Structures seen with a microscope (e.g., cells, tissues).

  • Developmental Anatomy: Changes in structure throughout the lifespan.

Principle of Complementarity

• The function of a body part depends on its structure; structure and function are inseparable.

• Example: Bones can support weight because of their hard mineralized structure.

Levels of Structural Organization

• Chemical Level: Atoms and molecules.

• Cellular Level: Cells and their organelles.

• Tissue Level: Groups of similar cells.

• Organ Level: Contains two or more types of tissues.

• Organ System Level: Organs that work closely together.

• Organismal Level: The human organism as a whole.

Organ Systems of the Body

System	Major Organs	Functions
Integumentary	Skin, hair, nails, glands	Protection, vitamin D synthesis
Skeletal	Bones, cartilages, ligaments	Support, movement, blood cell formation
Muscular	Skeletal muscles	Movement, heat generation
Nervous	Brain, spinal cord, nerves	Control, response to stimuli
Endocrine	Pituitary, thyroid, adrenal glands, etc.	Hormone secretion, regulation of processes
Cardiovascular	Heart, blood vessels	Transport of blood, nutrients, gases
Lymphatic/Immunity	Lymph nodes, spleen, thymus	Fluid return, immunity
Respiratory	Lungs, trachea, bronchi	Gas exchange
Digestive	Stomach, intestines, liver	Breakdown and absorption of food
Urinary	Kidneys, bladder	Elimination of wastes, water balance
Reproductive	Testes, ovaries, uterus	Production of offspring

Requirements for Life

• Maintaining boundaries: Separation between internal and external environments.

• Movement: Of body, organs, and cells.

• Responsiveness: Ability to sense and respond to stimuli.

• Digestion: Breakdown of food for absorption.

• Metabolism: All chemical reactions in the body.

• Excretion: Removal of wastes.

• Reproduction: Cellular and organismal reproduction.

• Growth: Increase in size or number of cells.

Homeostasis

• Definition: Maintenance of a stable internal environment within narrow limits.

• Components of Homeostatic Control:

  1. Receptor: Detects changes (stimuli).

  2. Control Center: Determines set point, processes information.

  3. Effector: Carries out response.

• Feedback Mechanisms:

  • Negative Feedback: Reduces or shuts off original stimulus (e.g., body temperature, blood sugar).

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

• Homeostatic Imbalance: Can lead to disease; efficiency declines with age (e.g., dehydration in elderly).

Anatomical Terms and Body Planes

• Directional Terms: Superior, inferior, anterior, posterior, medial, lateral, proximal, distal, superficial, deep.

• Anatomical Position: Body erect, feet slightly apart, palms facing forward.

• Body Planes: Sagittal, frontal (coronal), transverse.

Serous Membranes

• Allow organs to slide without friction in ventral body cavities; not needed in dorsal cavities (brain, spinal cord).

Abdominopelvic Regions and Quadrants

• Four quadrants and nine regions are used to describe locations of organs in the abdominopelvic cavity.

Chapter 2: Chemistry Comes Alive

Matter, Energy, and Chemical Bonds

• Matter: Anything that occupies space and has mass.

• Energy: The capacity to do work; exists as kinetic (energy of motion) or potential (stored energy).

• Examples:

  • Food molecules (potential energy)

  • Muscle contraction (kinetic energy)

Chemical Elements and Compounds

• Elements: Unique substances that cannot be broken down by ordinary means (e.g., C, O, H, N).

• Molecule: Two or more atoms bonded together.

• Compound: Two or more different elements chemically bonded.

• Mixture: Substances physically blended, not chemically bonded.

Chemical Bonds

Bond Type	Description	Example
Ionic	Attraction between oppositely charged ions	NaCl (table salt)
Covalent	Sharing of electron pairs	Bond within H2O molecule
Hydrogen	Attraction between a hydrogen atom and an electronegative atom	Bonds between adjacent water molecules

• Strength: Covalent > Ionic > Hydrogen

Polar vs. Nonpolar Covalent Bonds

• Both involve electron sharing.

• Polar: Unequal sharing (e.g., H2O).

• Nonpolar: Equal sharing (e.g., O2).

Chemical Reactions

• Often irreversible in the body due to removal of products or energy constraints.

• Factors Affecting Rate: Particle size, concentration, temperature, catalysts (enzymes).

Water and Salts in Homeostasis

• Water: Polar molecule; dissolves salts, high heat capacity, high heat of vaporization.

• Salts: Ionic compounds that dissociate in water; important for nerve impulses and muscle contraction.

• Electrolytes: Substances that conduct electricity in solution (e.g., Na+, K+, Ca2+).

Acids, Bases, and pH

• Acid: Releases H+ in solution (proton donor).

• Base: Binds H+ (proton acceptor).

• Buffer: Minimizes pH changes.

• pH Scale: Based on H+ concentration; lower pH = more acidic.

Organic Molecules and Macromolecules

• Dehydration Synthesis: Joins monomers, releases water.

• Hydrolysis: Breaks polymers, consumes water.

• Four Types: Carbohydrates, lipids, proteins, nucleic acids.

Carbohydrates

• Monomers: Monosaccharides (e.g., glucose).

• Function: Main energy source.

• Ratio: C:H:O = 1:2:1.

Lipids

• Building Blocks: Fatty acids and glycerol.

• Types: Triglycerides (fats/oils), phospholipids, steroids (cholesterol).

• Function: Energy storage, insulation, membrane structure.

• Phospholipids: Form bilayers due to hydrophilic heads and hydrophobic tails.

Proteins

• Monomers: Amino acids.

• Bond: Peptide bond.

• Functions: Structure, enzymes, transport, movement, signaling, defense.

• Structure Levels: Primary, secondary, tertiary, quaternary.

• Denaturation: Loss of shape due to pH or temperature changes.

Enzymes

• Globular proteins acting as biological catalysts; lower activation energy.

• Substrate: The molecule acted upon.

Nucleic Acids (DNA and RNA)

Characteristic	DNA	RNA
Structure	Double stranded	Single stranded
Major Site	Nucleus	Cytoplasm
Sugar	Deoxyribose	Ribose
Bases	A, G, C, T	A, G, C, U
Function	Genetic instructions	Protein synthesis

• Base pairing in DNA: A-T, G-C (held by hydrogen bonds).

ATP (Adenosine Triphosphate)

• Main energy carrier in cells; formed by adding phosphate groups to an RNA nucleotide.

• Energy from glucose breakdown is stored in ATP bonds.

Chapter 3: Cells: The Living Units

Cell Structure

• Three Major Regions:

  1. Plasma Membrane: Selectively permeable barrier.

  2. Cytoplasm: Fluid containing organelles.

  3. Nucleus: Controls cellular activities.

Plasma Membrane Structure and Function

• Phospholipid bilayer with embedded proteins (fluid mosaic model).

• Polar, hydrophilic heads face outward; nonpolar, hydrophobic tails face inward.

• Membrane proteins perform specialized functions (transport, signaling, etc.).

Cell Junctions

Junction Type	Description
Tight Junction	Impermeable; prevents passage between cells
Desmosome	Anchoring; resists tearing
Gap Junction	Allows communication and ion passage

Membrane Transport

• Passive Transport: No energy required; includes diffusion (simple, facilitated) and osmosis.

• Active Transport: Requires ATP; includes primary (direct ATP use) and secondary (uses gradients created by primary transport).

• Vesicular Transport: Bulk movement via vesicles (endocytosis, exocytosis).

Types of Endocytosis

• Pinocytosis: Nonselective uptake of extracellular fluid.

• Phagocytosis: Engulfment of large particles via pseudopods.

• Receptor-Mediated Endocytosis: Selective uptake via membrane receptors.

Membrane Potential

• Voltage across the plasma membrane due to ion separation.

• Maintained by sodium-potassium pump (more Na+ outside, more K+ inside).

Cell Adhesion Molecules (CAMs)

• Anchor cells, assist in movement, attract immune cells, and transmit signals.

Organelles and Their Functions

• Mitochondria: ATP synthesis; inner membrane forms cristae to increase surface area.

• Ribosomes: Protein synthesis; free ribosomes make cytosolic proteins, membrane-bound ribosomes make membrane/exported proteins.

• Rough ER: Protein and membrane synthesis.

• Smooth ER: Lipid and steroid synthesis, detoxification, Ca2+ storage.

• Golgi Apparatus: Modifies, sorts, and packages proteins/lipids for secretion or use.

• Lysosomes: Intracellular digestion.

• Peroxisomes: Detoxification (e.g., hydrogen peroxide breakdown).

Cytoskeleton and Cell Extensions

• Microtubules: Form cilia and flagella (movement).

• Microvilli: Increase surface area for absorption.

Nucleus Structure

Component	Structure	Function
Nuclear Envelope	Double membrane with pores	Regulates entry/exit, separates nucleoplasm
Nucleoli	Dense bodies	Ribosome subunit production
Chromatin	DNA and proteins	Genetic material

Cell Cycle and DNA Replication

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

• Mitosis: Prophase, metaphase, anaphase, telophase.

• DNA Replication: Each new DNA molecule has one old and one new strand (semiconservative).

Protein Synthesis

• Gene: DNA segment coding for a polypeptide.

• Genetic Code: Triplet base sequences specify amino acids.

• Transcription: DNA to mRNA.

• Translation: mRNA to protein (involves tRNA, rRNA).

Chapter 4: Tissue: The Living Fabric

Epithelial Tissue

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

• Classification: By cell layers (simple, stratified) and shape (squamous, cuboidal, columnar).

• Glands: Specialized for secretion; can be unicellular (e.g., goblet cells) or multicellular, exocrine (with ducts) or endocrine (ductless, secrete hormones).

Connective Tissue

• Main Components: Ground substance, fibers, cells (extracellular matrix = ground substance + fibers).

• Functions: Binding/support, protection, insulation, fat storage, transport (blood).

• Classes: Connective tissue proper, cartilage, bone, blood.

Membranes

• Cutaneous: Skin; dry, protective.

• Mucous: Line open body cavities; secrete mucus.

• Serous: Line closed cavities; secrete serous fluid for lubrication.

Tissue Repair

• Steps:

  1. Inflammation

  2. Organization (restores blood supply)

  3. Permanent repair (regeneration or fibrosis)

• Regeneration: Replacement with same tissue type.

• Fibrosis: Replacement with scar tissue (dense connective tissue).

Chapter 5: The Integumentary System

Skin Structure

• Layers: Epidermis (keratinized stratified squamous epithelium), dermis (papillary and reticular layers), subcutaneous tissue (not part of skin, mostly adipose tissue).

Epidermal Layers

• Stratum Basale: Source of new cells, contains melanocytes.

• Stratum Spinosum: Dendritic cells abundant.

• Stratum Granulosum: Keratinization begins, granules accumulate.

• Stratum Lucidum: Only in thick skin.

• Stratum Corneum: Dead cells, protection, continually shed.

Dermis

• Papillary Layer: Areolar connective tissue.

• Reticular Layer: Dense irregular connective tissue.

Skin Color

• Melanin: Produced by melanocytes; provides UV protection.

• Carotene: Yellow-orange pigment from diet.

• Hemoglobin: Crimson pigment in red blood cells; visible in light skin.

Glands

Feature	Eccrine Sweat Glands	Sebaceous Glands
Location	Palms, soles, forehead	Everywhere except palms/soles
Secretion	Sweat (hypotonic filtrate)	Sebum (oil)
Function	Thermoregulation	Lubrication
Duct Ends	Skin surface	Hair follicle

• Apocrine Glands: Found in axillary/anogenital regions; secrete viscous fluid, function as scent glands.

Functions of Skin

• Protection, excretion, temperature regulation, absorption, vitamin D synthesis.

• Regulates body temperature via sweat and blood flow.

• Converts cholesterol to vitamin D precursor in sunlight, aiding calcium absorption.

Burns

Type	Description
First-degree	Only epidermis damaged; redness, swelling (e.g., sunburn)
Second-degree	Epidermis and upper dermis; blisters
Third-degree	Full-thickness; gray-white, cherry red, or blackened; destroys nerve endings; least painful

• Serious burns threaten life due to fluid loss and infection risk.