Comprehensive Study Notes: Human Anatomy and Physiology (ANP) – Units 1 & 2

Structural Organization of the Human Body

Hierarchical Levels of Organization

The human body is organized into a hierarchy of structural levels, each building upon the previous to form a complete organism.

• Chemical Level: Atoms and molecules (e.g., Ca2+, troponin)

• Cellular Level: Basic living units (e.g., cardiomyocyte)

• Tissue Level: Groups of similar cells (e.g., cardiac muscle tissue)

• Organ Level: Structures composed of multiple tissue types (e.g., heart)

• Organ System Level: Groups of organs with a common function (e.g., cardiovascular system)

• Organismal Level: The complete human being

Example: Human → Cardiovascular system → Heart → Cardiac muscle tissue → Cardiomyocyte → Ca2+/troponin

Anatomical Position

The anatomical position is a standardized reference for describing locations and directions on the human body.

• Standing upright, feet flat, toes forward, eyes forward

• Arms at sides, palms facing forward, thumbs lateral

Purpose: Ensures consistency in anatomical terminology and reference for directional terms.

Note: Left and right always refer to the subject's left and right.

Body Planes and Sections

• Frontal (Coronal) Plane: Divides body into anterior and posterior parts (ear to ear)

• Sagittal Plane: Divides body into right and left parts (between the eyes)

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

Directional Terms

• Anterior/Posterior: Front/back

• Superior/Inferior: Above/below

• Medial/Lateral: Toward/away from midline

• Proximal/Distal: Closer to/farther from trunk or point of origin

• Superficial/Deep: Toward/away from body surface

• Ipsilateral/Contralateral: Same side/opposite side

• Cranial/Caudal: Toward head/toward tail

Survey of Body Systems

• Reproductive – Gonads, ducts, external genitalia; produces offspring

• Endocrine – Glands (pituitary, thyroid, etc.); hormone secretion

• Skeletal – Bones, cartilage, ligaments; support, protection, movement

• Muscular – Skeletal muscles; movement, heat production

• Digestive – Mouth, esophagus, stomach, intestines; nutrient absorption

• Urinary – Kidneys, bladder; waste elimination, fluid balance

• Lymphatic – Lymph nodes, vessels; immunity, fluid return

• Cardiovascular – Heart, blood vessels; transport of substances

• Respiratory – Lungs, trachea; gas exchange

• Integumentary – Skin, hair, nails; protection, temperature regulation

• Nervous – Brain, spinal cord, nerves; control, communication

Basic Anatomical Terminology

• Anatomy: Study of structure and location

• Physiology: Study of function and mechanisms

Body Cavities and Abdominopelvic Regions

• Dorsal Cavity: Cranial (brain), vertebral (spinal cord)

• Ventral Cavity: Thoracic (lungs, heart), abdominal (digestive organs), pelvic (reproductive organs, bladder)

Serous Membranes: Double-layered membranes (visceral and parietal) with serous fluid to reduce friction. Found in pleura (lungs), pericardium (heart), peritoneum (abdominal organs).

Quadrant	Major Structures
Right Upper (RUQ)	Liver, gallbladder, ascending & transverse large intestine
Left Upper (LUQ)	Stomach, spleen, part of liver, descending & transverse large intestine
Right Lower (RLQ)	Appendix, bladder, ascending large intestine, small intestine
Left Lower (LLQ)	Descending & sigmoid colon, small intestine, bladder

Region	Major Structures
Right Hypochondriac	Liver, gallbladder
Epigastric	Stomach, liver
Left Hypochondriac	Spleen
Right Lumbar	Ascending large intestine
Umbilical	Small intestine
Left Lumbar	Descending large intestine
Right Iliac	Ascending large intestine, ovary (female)
Hypogastric	Bladder, reproductive organs
Left Iliac	Descending large intestine, ovary (female)

Histology and Tissue Types

Definition and Major Tissue Types

• Histology: Study of tissues at the microscopic level

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

• Connective: Supports, binds, protects, stores energy; includes bone, cartilage, blood, adipose

• Muscle: Contracts to produce movement; includes skeletal, cardiac, smooth

• Nervous: Conducts electrical impulses; includes neurons and supporting cells

The Integumentary System

General Composition

• Epidermis: Stratified squamous epithelium; contains melanocytes, nerve endings

• Dermis: Connective tissue; papillary (areolar) and reticular (dense irregular) layers

• Hypodermis (Subcutaneous): Mostly adipose tissue

The integument is considered an organ because it combines multiple tissue types (epithelial, connective, muscle, nervous) to perform protective and sensory functions.

The Skeletal System

Major Functions

• Support and protection

• Mineral storage (e.g., calcium, phosphate)

• Blood cell formation (hematopoiesis)

• Energy storage (yellow marrow)

• Movement (muscle attachment)

Structural Components

• Bones: Main structural framework

• Ligaments: Connect bone to bone

• Tendons: Connect muscle to bone

• Cartilage: Cushions joints, absorbs shock

• Joints (Articulations): Allow movement

Classification of Bones by Shape

• Flat Bones: Thin, curved (e.g., ribs, sternum, scapula)

• Long Bones: Longer than wide, two ends (e.g., femur, humerus)

• Short Bones: Cube-shaped (e.g., carpals, tarsals, patella)

• Irregular Bones: Complex shapes (e.g., vertebrae, hip bones)

Bone Structure: Compact vs. Spongy

• Compact Bone: Dense, strong, forms outer layer

• Spongy (Trabecular) Bone: Honeycomb structure, contains marrow

Axial vs. Appendicular Skeleton

• Axial: Skull, vertebral column, ribs, sternum

• Appendicular: Limbs, shoulder and pelvic girdles

Common Bone Markings

• Condyle: Rounded articular projection

• Tubercle: Small, rough projection for muscle attachment

• Foramen: Hole for nerves/vessels

• Canal: Passageway through bone

• Others: Tuberosity, trochanter, epicondyle, spine, process, crest, facet, fissure, fossa

Gross Anatomy of Long Bones

• Epiphyses: Ends of long bones, contain spongy bone and red marrow

• Diaphysis: Shaft, contains compact bone and medullary cavity

• Medullary Cavity: Central cavity, contains marrow

• Red Marrow: Hematopoietic (blood cell formation)

• Yellow Marrow: Fat storage

Distribution of Marrow: All marrow is red in children; with age, most converts to yellow except in axial skeleton, girdles, and proximal femur/humerus.

Male vs. Female Pelvis

• Female: Wider opening, shallower ilia, wider pubic angle

• Male: Narrower, deeper, smaller pubic angle

Joints (Articulations)

Anatomical Classification

• Fibrous: Immovable or slightly movable (sutures, gomphoses, syndesmoses)

• Cartilaginous: Slightly movable (synchondroses, symphyses)

• Synovial: Freely movable, joint cavity, articular cartilage, synovial fluid

Joint Type	Subtype	Example
Fibrous	Suture	Skull
Fibrous	Gomphosis	Teeth in sockets
Fibrous	Syndesmosis	Interosseous membrane (radius/ulna)
Cartilaginous	Synchondrosis	Epiphyseal plate, first rib-sternum
Cartilaginous	Symphysis	Pubic symphysis, intervertebral discs
Synovial	Plane	Wrist, ankle
Synovial	Hinge	Elbow, knee
Synovial	Pivot	Atlas-axis, radius-ulna
Synovial	Condylar	Metacarpophalangeal joints
Synovial	Saddle	Thumb, sternoclavicular
Synovial	Ball-and-socket	Shoulder, hip

Functional Classification

• Synarthrosis: Immovable (e.g., skull sutures)

• Amphiarthrosis: Slightly movable (e.g., pubic symphysis)

• Diarthrosis: Freely movable (e.g., shoulder, knee)

Movements at Joints

• Flexion/Extension: Decrease/increase joint angle

• Abduction/Adduction: Away from/toward midline

• Rotation: Bone turns around its axis

• Circumduction: Circular movement (cone in space)

• Inversion/Eversion: Sole of foot toward/away from midline

• Protraction/Retraction: Jaw forward/backward

• Elevation/Depression: Jaw up/down

• Supination/Pronation: Palm anterior/posterior

Muscle Tissue

General Properties and Functions

• All muscle types contain actin and myosin filaments organized into sarcomeres

• Excitable, contractile, extensible, and elastic

Types of Muscle Tissue

• Skeletal: Voluntary, striated, multinucleated; attached to bones

• Cardiac: Involuntary, striated, uninucleate, intercalated discs; heart

• Smooth: Involuntary, non-striated, uninucleate; walls of organs and vessels

Organization of Skeletal Muscle

• Myofibrils → Muscle fibers (myocytes) → Fascicle → Muscle

• Connective Tissue Layers:

  • Endomysium: Around muscle fibers (areolar CT)

  • Perimysium: Around fascicles (dense irregular CT)

  • Epimysium: Around whole muscle (dense irregular CT)

Nomenclature of Skeletal Muscles

• Action: Flexor, extensor, adductor, etc.

• Appearance: Deltoid (triangle), quadratus (square), serratus (saw-toothed)

• Location: Brachialis (arm), femoris (thigh)

• Size: Maximus/minimus, major/minor, longus/brevis

• Direction: Rectus (straight), oblique (angled)

• Origins/Insertions: Sternocleidomastoid

• Number of Heads: Biceps (2), triceps (3)

Muscle Compartments and Functional Groupings

• Compartments are groups of muscles with similar function, innervated by a single nerve, surrounded by fascia

• Examples:

  • Anterior arm: Flexion (musculocutaneous nerve)

  • Posterior arm: Extension (radial nerve)

  • Anterior thigh: Hip flexion, knee extension (femoral nerve)

  • Posterior thigh: Hip extension, knee flexion (tibial nerve)

  • Medial thigh: Adduction (obturator nerve)

  • Anterior leg: Dorsiflexion (deep fibular nerve)

  • Posterior leg: Plantarflexion (tibial nerve)

  • Lateral leg: Eversion, plantarflexion (superficial fibular nerve)

Nervous System

General Functions

• Coordinates actions of other systems

• Receives, processes, and responds to stimuli

Organization

• CNS: Brain and spinal cord; integration and control

• PNS: Nerves and ganglia; communication between CNS and body

• Motor (Efferent): CNS to effectors (muscles/glands)

• Sensory (Afferent): Receptors to CNS

• Somatic: Voluntary control (skeletal muscle)

• Autonomic: Involuntary (organs, glands); includes sympathetic and parasympathetic

• Somatic Sensory: Touch, proprioception, vision, hearing, balance

• Visceral Sensory: Organ sensations, taste, smell, chemical changes

Gray and White Matter

• Spinal Cord: Gray matter deep, white matter superficial

• Brain: White matter deep, gray matter superficial (cortex)

Structure of a Nerve

• Endoneurium: Around individual axons

• Perineurium: Around fascicles

• Epineurium: Around whole nerve

• Contains neuroglia (e.g., Schwann cells), blood vessels

Nucleus vs. Ganglion

• Nucleus: Cluster of neuron cell bodies in CNS

• Ganglion: Cluster of neuron cell bodies in PNS

Tract vs. Nerve

• Tract: Bundle of axons in CNS

• Nerve: Bundle of axons in PNS

Protection of CNS

• Cranial Bones & Vertebral Column: Physical protection

• Meninges: Dura mater (2 layers in brain, 1 in spinal cord), arachnoid mater, pia mater

• Dural Venous Sinuses: Drain blood from brain

• Spaces: Epidural (vertebral column), subdural, subarachnoid (contains CSF)

• CSF: Nourishes, removes waste, shock absorption

Brain Anatomy

Developmental Vesicles

• Primary: Prosencephalon (forebrain), mesencephalon (midbrain), rhombencephalon (hindbrain)

• Secondary: Telencephalon (cerebrum), diencephalon (thalamus, hypothalamus), mesencephalon (midbrain), metencephalon (pons, cerebellum), myelencephalon (medulla)

Major Brain Regions

• Cerebrum: Higher processing, 5 lobes (frontal, parietal, temporal, occipital, insula)

• Diencephalon: Thalamus (sensory relay), hypothalamus (homeostasis, endocrine), epithalamus (pineal gland, sleep)

• Brainstem: Midbrain (reflexes), pons (relay, cranial nerves), medulla (vital centers, decussation)

• Cerebellum: Coordination, posture, equilibrium

Ventricular System

• Lateral ventricles, third ventricle, fourth ventricle, cerebral aqueduct, choroid plexuses (produce CSF)

Blood-Brain Barrier (BBB)

• Tight junctions in capillaries restrict passage of substances, protecting brain tissue

Cerebral Landmarks

• Longitudinal Fissure: Divides hemispheres

• Lateral Sulcus: Separates frontal and temporal lobes

• Central Sulcus: Separates frontal and parietal lobes

• Transverse Fissure: Separates cerebrum and cerebellum

• Precentral Gyrus: Primary motor cortex

• Postcentral Gyrus: Primary somatosensory cortex

Cerebral Cortex Functional Areas

• Primary Motor Cortex: Initiates voluntary movement

• Primary Somatosensory Cortex: Processes touch, proprioception

• Primary Visual Cortex: Occipital lobe

• Primary Auditory Cortex: Temporal lobe

• Primary Olfactory Cortex: Inferior medial temporal lobe

• Primary Gustatory Cortex: Insula

Broca's vs. Wernicke's Area

• Broca's Area: Speech production (frontal lobe, left hemisphere)

• Wernicke's Area: Language comprehension (temporal lobe, left hemisphere)

Cerebral White Matter Tracts

• Association: Connect regions within same hemisphere

• Commissural: Connect hemispheres (e.g., corpus callosum)

• Projection: Connect cortex to lower brain/spinal cord

Cranial Nerves

Number	Name	Function	Type
I	Olfactory	Smell	Sensory
II	Optic	Vision	Sensory
III	Oculomotor	Eye movement, constriction	Motor
IV	Trochlear	Eye movement	Motor
V	Trigeminal	Facial sensation, chewing	Mixed
VI	Abducens	Eye abduction	Motor
VII	Facial	Facial expression, taste, glands	Mixed
VIII	Vestibulocochlear	Hearing, balance	Sensory
IX	Glossopharyngeal	Taste, swallowing, saliva	Mixed
X	Vagus	Parasympathetic, voice, visceral sense	Mixed
XI	Accessory	Head/shoulder movement	Motor
XII	Hypoglossal	Tongue movement	Motor

Parasympathetic Components: III, VII, IX, X

Spinal Cord Anatomy

• Enlargements: Cervical and lumbar (limb innervation)

• Conus Medullaris: Tapered end (L1-L2)

• Cauda Equina: Nerve roots at end of vertebral canal

• Filum Terminale: Connective tissue anchor to coccyx

Root	Location	Function
Anterior (Ventral)	Ventral side	Motor (efferent), no ganglia
Posterior (Dorsal)	Dorsal side	Sensory (afferent), contains ganglia

• Gray Matter: Anterior, lateral, posterior horns; gray commissure; central canal (CSF)

• White Matter: Anterior, lateral, posterior funiculi (tracts)

Ascending tracts: Sensory information to brain Descending tracts: Motor commands from brain

Additional info: For equations, see muscle contraction (sliding filament theory) and nerve conduction (Nernst equation, not detailed here).