Anatomy and Physiology I (BIO 250) - Comprehensive Study Guide: Learning Objectives and Key Concepts

Introduction to Anatomy and Physiology

Defining Anatomy and Physiology

Anatomy is the study of the structure of body parts and their relationships to one another, while physiology is the study of the function of the body’s structural machinery. The two disciplines are closely interrelated, as the structure of a body part often determines its function.

• Anatomy: Examines the form and organization of body structures (e.g., bones, muscles, organs).

• Physiology: Explores how those structures work (e.g., muscle contraction, nerve signaling).

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

Levels of Organization in the Human Body

The human body is organized from the simplest to the most complex levels:

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

• Cellular Level: Cells and their organelles (e.g., muscle cells, neurons).

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

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

• Organ System Level: Organs working together (e.g., digestive system).

• Organismal Level: The complete living being.

Anatomical Terminology and Body Organization

Anatomical Position and Directional Terms

The anatomical position is a standard reference point: the body is erect, facing forward, arms at the sides with palms facing forward. Right and left always refer to the subject’s right and left.

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

• Example: The heart is medial to the lungs.

Body Planes and Sections

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

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

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

Body Cavities and Regions

• Dorsal Cavity: Contains the cranial and vertebral cavities.

• Ventral Cavity: Includes the thoracic and abdominopelvic cavities.

• Abdominopelvic Quadrants: Right upper, left upper, right lower, left lower.

• Abdominopelvic Regions: Nine regions (e.g., epigastric, umbilical, hypogastric).

Homeostasis and Feedback Systems

Negative vs. Positive Feedback

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

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

• Pathway Steps: Stimulus → Receptor → Control Center → Effector → Response.

• Importance: Negative feedback is most common because it maintains stability (homeostasis).

Chemical Level of Organization

Atoms, Elements, Molecules, and Compounds

• Atom: Smallest unit of matter.

• Element: Substance made of one type of atom.

• Molecule: Two or more atoms bonded together.

• Compound: Molecule containing two or more different elements.

• Electron Shells: Chemical stability depends on the number of electrons in the outer shell.

• Atomic Number: Number of protons.

• Mass Number: Protons + neutrons.

• Atomic Weight: Average mass of all isotopes.

Chemical Bonds

• Covalent Bonds: Sharing of electron pairs (e.g., H2O).

• Ionic Bonds: Transfer of electrons (e.g., NaCl).

• Hydrogen Bonds: Weak attractions between polar molecules (e.g., between water molecules).

Properties of Water

• High heat capacity (absorbs heat without large temperature change).

• High heat of vaporization (important for cooling).

• Universal solvent (dissolves many substances).

• Reactivity (involved in hydrolysis and dehydration reactions).

• Cushioning (protects organs).

pH and Buffers

• pH Scale: 0–14; Acidic: <7, Neutral: 7, Basic (Alkaline): >7.

• Salt: Ionic compound that dissociates in water.

• Acid: Releases H+ ions.

• Base: Accepts H+ ions.

• Buffer: Resists changes in pH.

Cellular Level of Organization

Cell Membranes and Organic Molecules

• Fluid Mosaic Model: Describes the structure of cell membranes as a mosaic of proteins floating in a sea of lipids.

• Organic Molecules: Contain carbon; include carbohydrates, proteins, lipids, nucleic acids.

• Monomers and Polymers: Monomers are building blocks; polymers are chains of monomers.

• Carbohydrates: Monosaccharides (glucose), disaccharides, polysaccharides (glycogen).

• Proteins: Amino acids; structure determines function.

• Lipids: Fatty acids, triglycerides, phospholipids, steroids.

• Nucleic Acids: Nucleotides; DNA and RNA.

• Enzymes: Biological catalysts; affected by temperature, pH, substrate concentration.

Cellular Organelles

• Organelle: Specialized subunit within a cell (e.g., nucleus, mitochondria, endoplasmic reticulum).

• Function Examples: Mitochondria produce ATP; ribosomes synthesize proteins.

Membrane Transport

• Osmosis: Diffusion of water across a selectively permeable membrane.

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

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

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

• Solution Effects: Hypertonic (cell shrinks), isotonic (no change), hypotonic (cell swells).

Cell Cycle and Division

• Phases: G1 (growth), S (DNA synthesis), G2 (preparation), M (mitosis/cell division).

• Mitosis: Somatic cell division; produces two identical cells.

• Meiosis: Reproductive cell division; produces gametes with half the chromosome number.

Tissue Level of Organization

Types and Functions of Tissues

• Epithelial Tissue: Covers surfaces; functions include protection, absorption, secretion.

• Connective Tissue: Supports and binds other tissues; includes bone, cartilage, blood.

• Muscle Tissue: Produces movement; types include skeletal, cardiac, smooth.

• Nervous Tissue: Transmits electrical impulses; includes neurons and glial cells.

Connective Tissue Locations and Functions

• Loose Connective Tissue: Underlies epithelia.

• Dense Connective Tissue: Tendons, ligaments.

• Cartilage: Joints, ear, nose.

• Bone: Skeleton.

• Blood: Circulatory system.

Bone Cells and Tissue Formation

• Osteoblasts: Build bone.

• Osteocytes: Maintain bone.

• Osteoclasts: Break down bone.

Neurons vs. Glial Cells

• Neurons: Transmit electrical signals; have axons and dendrites.

• Glial Cells: Support, protect, and nourish neurons.

Integumentary System

Layers of the Skin

• Epidermis: Five layers (stratum basale, spinosum, granulosum, lucidum, corneum).

• Dermis: Papillary (areolar connective tissue) and reticular (dense irregular connective tissue) layers.

• Subcutaneous Layer: Also called hypodermis; stores fat, anchors skin.

Accessory Structures

• Hair: Protection, sensation.

• Nails: Protect fingertips.

• Glands: Sweat (thermoregulation), sebaceous (lubrication).

Skeletal System

Bones and Bone Markings

• Classification by Shape: Long, short, flat, irregular, sesamoid.

• Bone Markings: Projections, depressions, openings (e.g., foramen, process, fossa).

Bone Formation and Growth

• Intramembranous Ossification: Bone develops from fibrous membrane (e.g., skull).

• Endochondral Ossification: Bone forms by replacing cartilage (e.g., long bones).

• Hormonal Regulation: Growth hormone, thyroid hormone, sex hormones.

• Fracture Repair: Hematoma formation → fibrocartilaginous callus → bony callus → bone remodeling.

Axial and Appendicular Skeleton

• Axial Skeleton: Skull, vertebral column, thoracic cage.

• Appendicular Skeleton: Limbs and girdles.

• Bone Markings: Identified for both axial and appendicular bones.

• Fetal vs. Adult Skull: Fontanelles in infants; fused sutures in adults.

• Male vs. Female Skeleton: Pelvic differences for childbirth.

Joints

Classification and Structure

• Functional Classification: Synarthroses (immovable), amphiarthroses (slightly movable), diarthroses (freely movable).

• Anatomical Classification: Fibrous, cartilaginous, synovial joints.

• Synovial Joints: Articular cartilage, joint cavity, synovial fluid, ligaments.

• Movements: Flexion, extension, abduction, adduction, rotation, circumduction.

• Types: Plane, hinge, pivot, condyloid, saddle, ball-and-socket.

Muscular System

Muscle Organization and Contraction

• Connective Tissue: Epimysium, perimysium, endomysium.

• Organization: Muscle → fascicle → fiber → myofibril → myofilament.

• Sliding Filament Theory: Actin and myosin filaments slide past each other to shorten muscle.

• Contraction Sequence: Nerve impulse → calcium release → cross-bridge formation → power stroke → relaxation.

• Isometric vs. Isotonic: Isometric (no length change), isotonic (muscle changes length).

• Sodium-Potassium ATPase Pump: Maintains resting membrane potential ($3 \mathrm{Na}^+ \text{ out}, 2 \mathrm{K}^+ \text{ in}$).

Muscle Actions and Identification

• Prime Movers, Antagonists, Synergists: Roles in movement.

• Origin, Insertion, Action: Key for muscle identification.

Nervous System

Central vs. Peripheral Nervous System

• CNS: Brain and spinal cord.

• PNS: Cranial and spinal nerves.

• Somatic vs. Autonomic: Voluntary vs. involuntary control.

Neuroglial Cells and Conduction

• Neuroglia: Support cells (e.g., astrocytes, Schwann cells).

• Saltatory Conduction: Faster in myelinated axons; increased by larger diameter.

Nerve Impulse and Synapses

• Propagation: Depolarization → repolarization → refractory periods.

• Chemical Synapse: Presynaptic neuron releases neurotransmitter to postsynaptic cell.

Spinal Cord and Brain

• Spinal Cord Anatomy: Central canal, gray and white matter.

• Spinal Nerve Plexuses: Cervical, brachial, lumbar, sacral.

• Meninges: Dura mater, arachnoid mater, pia mater.

• Brain Regions: Cerebrum, diencephalon, brainstem, cerebellum.

• Cranial Nerves: Twelve pairs, each with specific functions.

Autonomic and Special Senses

• Sympathetic vs. Parasympathetic: Fight-or-flight vs. rest-and-digest.

• Olfaction Pathway: Receptors → olfactory bulb → brain.

• Special vs. General Senses: Special (vision, hearing, taste, smell, equilibrium) vs. general (touch, pain, temperature).

• Eye Anatomy and Light Pathway: Cornea → aqueous humor → lens → vitreous humor → retina.

Term	Definition	Example
Atom	Smallest unit of matter	Hydrogen atom
Element	Substance of one type of atom	Oxygen
Molecule	Two or more atoms bonded	O2
Compound	Molecule with different elements	H2O

Additional info: This study guide is based on the learning objectives for Anatomy and Physiology I (BIO 250) and covers foundational concepts, terminology, and systems as outlined in the course syllabus.