Anatomy and Physiology I: Comprehensive Study Guide

Chapter 1 - The Human Body: An Overview

Anatomy vs Physiology

Anatomy is the study of the structure of body parts and their relationships, while physiology focuses on the function of these parts.

• Anatomy: Examines the physical form, location, and organization of organs and tissues.

• Physiology: Explores how body parts work and interact to sustain life.

• Example: Studying the heart's chambers (anatomy) vs. understanding how the heart pumps blood (physiology).

Principle of Complementarity of Structure and Function

Structure and function are interrelated; the form of a body part enables its function.

• Key Point: The anatomy of an organ determines its physiological role.

• Example: The thin walls of alveoli allow efficient gas exchange.

Structural Organization of the Body

The human body is organized hierarchically from simple to complex levels.

• Chemical level: Atoms and molecules

• Cellular level: Cells and their organelles

• Tissue level: Groups of similar cells

• Organ level: Two or more tissues working together

• Organ system level: Organs working together

• Organismal level: The complete living being

Homeostasis (Feedback Loops)

Homeostasis is the maintenance of a stable internal environment through feedback mechanisms.

• Negative feedback: Reduces deviation from a set point (e.g., temperature regulation).

• Positive feedback: Enhances deviation (e.g., blood clotting).

• Example: Regulation of blood glucose by insulin.

Anatomical Position

The standard reference position for anatomical terminology.

• Standing upright, facing forward, arms at sides, palms forward.

• Importance: Provides consistency in describing locations and directions.

Membranes and Cavities

Body cavities house organs and are lined by membranes.

• Dorsal cavity: Contains brain and spinal cord.

• Ventral cavity: Contains thoracic and abdominopelvic cavities.

• Serous membranes: Line cavities and reduce friction (e.g., pleura, pericardium).

Chapter 3 - Cells: The Living Units

General Structure of a Cell and Organelles

Cells are the basic units of life, containing specialized organelles.

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

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

• Ribosomes: Synthesize proteins; found free in cytoplasm or attached to ER.

The Plasma Membrane

The plasma membrane surrounds the cell, controlling entry and exit of substances.

• Structure: Phospholipid bilayer with embedded proteins.

• Function: Selective permeability, communication, protection.

• Membrane Transport: Includes passive (diffusion, osmosis) and active (pumps, endocytosis) mechanisms.

• Example: Sodium-potassium pump maintains ion gradients.

Chapter 4 - Tissue: The Living Fabric

Structure and Function of 4 Basic Tissue Types

Tissues are groups of cells with similar structure and function.

• Epithelial tissue: Covers surfaces, lines cavities, forms glands; functions in protection, absorption, secretion.

• Connective tissue: Supports, protects, binds other tissues; four types: loose, dense, cartilage, bone.

• Muscle tissue: Contracts to produce movement; three types: skeletal, cardiac, smooth.

• Nervous tissue: Transmits electrical impulses; consists of neurons and supporting glial cells.

Chapter 5 - The Integumentary System

Epidermis

The epidermis is the outermost layer of skin, composed mainly of keratinocytes.

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

Dermis

The dermis lies beneath the epidermis, providing strength and flexibility.

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

• Function: Houses blood vessels, nerves, glands, hair follicles.

Factors Influencing Skin Color

• Melanin: Pigment produced by melanocytes.

• Carotene: Yellow-orange pigment.

• Hemoglobin: Red pigment in blood.

Disease and Ailments Affecting Skin Color

• Jaundice: Yellowing due to bilirubin buildup.

• Cyanosis: Bluish tint from low oxygen.

• Albinism: Lack of melanin production.

Chapter 6 – Bones and Skeletal Tissue

Cartilage

Cartilage is a flexible connective tissue found in joints and other structures.

• Types: Hyaline, elastic, fibrocartilage.

• Types of growth: Interstitial (within), appositional (surface).

Bones

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

• Gross structure: Compact and spongy bone; diaphysis and epiphysis.

• Microscopic structure: Osteocytes, osteoblasts, osteoclasts.

• Epiphyseal plate: Site of bone growth in children.

• Bone remodeling: Regulated by negative feedback; involves resorption and deposition.

Chapter 8 - Joints

Structural and Functional Classifications

Joints connect bones and allow movement.

• Structural: Fibrous, cartilaginous, synovial.

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

Synovial Joints

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

• Bursae and tendon sheaths: Reduce friction.

• Stability factors: Shape of articular surfaces, ligaments, muscle tone.

• Examples: Shoulder, knee, hip.

Chapter 9 – Muscles

Types of Muscle Tissue

• Skeletal: Voluntary, striated.

• Cardiac: Involuntary, striated, found in heart.

• Smooth: Involuntary, non-striated, found in walls of organs.

Microscopic Structure of Muscle Fibers

• Myofibrils: Contain actin and myosin filaments.

• Sarcomere: Functional unit of muscle contraction.

Sliding Filament Model

Muscle contraction occurs as actin and myosin filaments slide past each other.

• Key Point: ATP and calcium are required for contraction.

Action Potential Steps

• Depolarization, repolarization, restoration of resting potential.

Role of Calcium and ATP in Muscle Contractions

• Calcium: Triggers binding of actin and myosin.

• ATP: Provides energy for contraction and relaxation.

Chapter 11- Nervous System and Nervous Tissue

Divisions of the Nervous System

Division	Main Components	Function
CNS	Brain, Spinal Cord	Integration, processing
PNS	Nerves, Ganglia	Communication between CNS and body

Glial Cells

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

• PNS: Schwann cells, satellite cells.

Structure and Function of a Neuron

• Cell body: Contains nucleus.

• Dendrites: Receive signals.

• Axon: Transmits signals.

• Myelination: Increases speed of conduction.

Membrane Potential

• Resting membrane potential: Maintained by ion gradients.

• Graded potential: Local changes in membrane potential.

• Action potential: Rapid, all-or-none electrical signal.

• Saltatory conduction: Action potential jumps between nodes of Ranvier.

Synapse and Neurotransmitters

• Synapse: Junction between neurons.

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

• Functions: Excitatory or inhibitory effects.

Chapter 12 – Central Nervous System

Cerebrum

• Structure: Two hemispheres, five lobes.

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

• Grey vs white matter: Grey = cell bodies; white = myelinated axons.

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

Diencephalon

• Regions: Thalamus (relay), hypothalamus (homeostasis), epithalamus.

• Hypothalamus-pituitary interaction: Controls endocrine system.

Brain Stem

• Regions: Midbrain, pons, medulla oblongata.

• Functions: Basic life functions (breathing, heart rate).

Cerebellum

• Structure: Two hemispheres, cortex.

• Function: Coordination, balance.

Brain Protection

• Meninges: Dura, arachnoid, pia mater.

• Blood-brain barrier: Limits passage of substances.

Common Brain Injuries

• Concussion, contusion, stroke.

Spinal Cord

• Functions: Conducts signals, reflexes.

• Cross-section anatomy: Grey matter (cell bodies), white matter (axons).

• Trauma and disorders: Paralysis, spinal cord injury.

Chapter 13 - Peripheral Nervous System

Types and Location of Sensory Receptors

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

• Location: Skin, muscles, organs.

Sensation vs Perception

• Sensation: Awareness of stimulus.

• Perception: Interpretation of stimulus.

Perception of Pain

• Involves nociceptors and central processing.

Structure and Function of Nerves

• Nerves: Bundles of axons; transmit signals.

Reflexes and Reflex Arc

• Reflex arc: Sensory receptor → sensory neuron → integration center → motor neuron → effector.

Chapter 14- The Autonomic Nervous System

Definition and Comparison with Somatic Nervous System

• Autonomic: Controls involuntary functions (heart, glands).

• Somatic: Controls voluntary movements (skeletal muscle).

• Effectors: Somatic = skeletal muscle; autonomic = smooth/cardiac muscle, glands.

• Efferent pathways: Somatic = single neuron; autonomic = two-neuron chain.

• Neurotransmitters: Somatic = acetylcholine; autonomic = acetylcholine, norepinephrine.

Parasympathetic & Sympathetic Divisions

• Parasympathetic: "Rest and digest"; conserves energy.

• Sympathetic: "Fight or flight"; mobilizes energy.

• Structure: Parasympathetic originates in brainstem and sacral spinal cord; ganglia near organs. Sympathetic originates in thoracolumbar spinal cord; ganglia near spinal cord.

• Fiber pathways: Parasympathetic = long preganglionic, short postganglionic; sympathetic = short preganglionic, long postganglionic.

Chapter 15- The Special Senses

Hearing

• Sound conduction pathway: External ear → tympanic membrane → ossicles → cochlea fluids.

• Anatomy of cochlea: Spiral organ with hair cells.

• Auditory pathway: Cochlear nerve → brainstem → auditory cortex.

Vision

• Anatomy of eye: Cornea, lens, retina.

• Rods & cones: Rods = dim light, cones = color vision.

• Colorblindness: Deficiency in cone cells.

• Astigmatism: Irregular curvature of cornea/lens.

• Pathway of light: Cornea → lens → retina.

Taste

• Taste buds: Papillae with gustatory cells.

• Types of receptors: Sweet, sour, salty, bitter, umami.