Anatomy and Physiology I: Comprehensive Study Notes

Chapter 1: The Human Body – An Overview

Anatomy vs. Physiology

Anatomy is the study of the structure of body parts and their relationships to one another. Physiology is the study of the function of the body’s structural machinery.

• Anatomy: Focuses on form, structure, and organization (e.g., bones, organs).

• Physiology: Explains how those structures work (e.g., how muscles contract).

• Principle of Complementarity: Structure determines function; what a structure can do depends on its form.

Structural Organization of the Body

The human body is organized in a hierarchy from simplest to most complex:

• 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: All organ systems combined

Homeostasis and Feedback Loops

Homeostasis is the maintenance of a stable internal environment. It is primarily regulated by feedback mechanisms:

• Negative feedback: Reduces or shuts off the original stimulus (e.g., body temperature regulation).

• Positive feedback: Enhances the original stimulus (e.g., blood clotting).

Anatomical Position, Membranes, and Cavities

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

• Body cavities: Dorsal (cranial and vertebral) and ventral (thoracic and abdominopelvic).

• Membranes: Serous membranes line body cavities and cover organs (parietal and visceral layers).

Chapter 3: Cells – The Living Units

General Structure of a Cell and Organelles

• Nucleus: Control center; contains DNA.

• Mitochondria: Site of ATP production; "powerhouse" of the cell.

• Ribosomes: Sites of protein synthesis; can be free or attached to rough ER.

The Plasma Membrane

• Structure: Phospholipid bilayer with embedded proteins.

• Function: Selectively permeable barrier; regulates entry/exit of substances.

• Membrane Transport:

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

  • Active transport: Requires ATP (e.g., sodium-potassium pump).

Chapter 4: Tissue – The Living Fabric

Four Basic Tissue Types

• Epithelial Tissue: Covers surfaces, lines cavities, forms glands. Functions: protection, absorption, filtration, secretion.

• Connective Tissue: Supports, protects, binds other tissues. Four types:

  • Connective tissue proper

  • Cartilage

  • Bone

  • Blood

• Muscle Tissue: Responsible for movement. Three types:

  • Skeletal (voluntary)

  • Cardiac (heart)

  • Smooth (walls of hollow organs)

• Nervous Tissue: Initiates and transmits electrical impulses; found in brain, spinal cord, nerves.

Chapter 5: The Integumentary System

Epidermis

• Cell types: Keratinocytes (produce keratin), melanocytes (produce melanin), dendritic cells (immune), Merkel cells (sensory).

Dermis

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

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

Skin Color

• Influenced by melanin, carotene, and hemoglobin.

• Diseases: Cyanosis (blue), jaundice (yellow), erythema (redness), pallor (pale).

Chapter 6: Bones and Skeletal Tissue

Cartilage

• Types: Hyaline, elastic, fibrocartilage.

• Growth: Appositional (new layers added), interstitial (expansion from within).

Bone

• Functions: Support, protection, movement, mineral storage, blood cell formation, fat storage, hormone production.

• Gross structure: Compact and spongy bone, diaphysis, epiphyses.

• Microscopic structure: Osteocytes, osteoblasts, osteoclasts, osteon (Haversian system).

• Epiphyseal plate: Site of bone growth in length.

• Bone remodeling: Regulated by negative feedback (e.g., calcium homeostasis).

Chapter 8: Joints

Structural and Functional Classifications

• Structural: Fibrous, cartilaginous, synovial.

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

Synovial Joints

• 6 Features: Articular cartilage, joint cavity, articular capsule, synovial fluid, reinforcing ligaments, nerves and blood vessels.

• Bursae and tendon sheaths: Reduce friction.

• Stability factors: Articular surfaces, ligaments, muscle tone.

• Examples: Shoulder, knee, hip.

Chapter 9: Muscles

Types of Muscle Tissue

• Skeletal, cardiac, smooth (see above for details).

Microscopic Structure of Muscle Fibers

• Myofibrils, sarcomeres, actin and myosin filaments.

Sliding Filament Model

• Muscle contraction occurs as myosin heads bind to actin, pulling filaments past each other.

Action Potential and Muscle Contraction

• Action potential travels along sarcolemma, triggers calcium release from sarcoplasmic reticulum.

• Calcium binds to troponin, allowing myosin-actin interaction.

• ATP is required for both contraction and relaxation.

Chapter 11: Nervous System and Nervous Tissue

Divisions of the Nervous System

• CNS: Brain and spinal cord.

• PNS: Cranial and spinal nerves.

Glial Cells

• CNS: Astrocytes, oligodendrocytes, microglia, ependymal cells.

• PNS: Schwann cells, satellite cells.

Structure and Function of a Neuron

• Cell body, dendrites (receive signals), axon (transmits signals), myelination increases speed.

Membrane Potentials

• Resting membrane potential: -70 mV, maintained by sodium-potassium pump.

• Graded potential: Local changes in membrane potential.

• Action potential: All-or-none electrical impulse.

• Saltatory conduction: Rapid transmission along myelinated axons.

Synapse and Neurotransmitters

• Synapse: Junction between neurons.

• Neurotransmitters: Chemical messengers (e.g., acetylcholine, dopamine, serotonin).

Chapter 12: Central Nervous System

Cerebrum

• Largest part; divided into 5 lobes (frontal, parietal, temporal, occipital, insula).

• Cerebral cortex: Higher functions (sensory, motor, association).

• Grey matter (cell bodies) vs. white matter (myelinated axons).

• Diseases: Parkinson’s (dopamine deficit), Huntington’s (genetic, neuron degeneration).

Diencephalon

• Includes thalamus (relay station), hypothalamus (homeostasis, pituitary control), epithalamus.

Brain Stem

• Midbrain, pons, medulla oblongata; controls vital functions.

Cerebellum

• Coordinates movement and balance.

Brain Protection

• Meninges (dura, arachnoid, pia mater), blood-brain barrier.

Spinal Cord

• Major functions: Conduction, reflexes.

• Cross-section: Grey matter (H-shaped), white matter (surrounds grey).

Chapter 13: Peripheral Nervous System

Sensory Receptors

• Types: Mechanoreceptors, thermoreceptors, photoreceptors, chemoreceptors, nociceptors.

• Location: Exteroceptors (external), interoceptors (internal), proprioceptors (muscles/joints).

Sensation vs. Perception

• Sensation: Awareness of stimulus.

• Perception: Interpretation of stimulus.

Pain Perception

• Nociceptors detect pain; perception modulated by brain.

Nerves and Reflexes

• Nerves: Bundles of axons in PNS.

• Reflex arc: Receptor, sensory neuron, integration center, motor neuron, effector.

Chapter 14: The Autonomic Nervous System

Overview and Comparison

• Autonomic nervous system (ANS): Controls involuntary functions (smooth muscle, cardiac muscle, glands).

• Somatic vs. Autonomic:

  • Effectors: Skeletal muscle (somatic), smooth/cardiac/glands (autonomic).

  • Efferent pathways: One neuron (somatic), two-neuron chain (autonomic).

  • Neurotransmitters: Acetylcholine (somatic), acetylcholine/norepinephrine (autonomic).

Parasympathetic vs. Sympathetic Divisions

• Parasympathetic: "Rest and digest"; craniosacral origin; ganglia near target organs; long preganglionic, short postganglionic fibers.

• Sympathetic: "Fight or flight"; thoracolumbar origin; ganglia near spinal cord; short preganglionic, long postganglionic fibers.

Chapter 15: The Special Senses

Hearing

• Sound conduction: External ear → tympanic membrane → ossicles → cochlea (fluid movement).

• Cochlea: Spiral organ of hearing; contains hair cells.

• Auditory pathway: Cochlea → cochlear nerve → brainstem → auditory cortex.

Vision

• Eye anatomy: Cornea, lens, retina, optic nerve.

• Rods (dim light, black/white) vs. cones (color, sharp vision).

• Colorblindness: Deficiency in cone pigments.

• Astigmatism: Irregular curvature of cornea/lens.

• Pathway of light: Cornea → aqueous humor → lens → vitreous humor → retina.

Taste

• Taste buds: Contain gustatory cells; located on papillae.

• Receptors: Sweet, sour, salty, bitter, umami.