ANP Study Guide: Integumentary, Skeletal, Muscular, and Nervous Systems

Integumentary System

Functions of the Integument

• Protection: Acts as a physical barrier against mechanical injury, pathogens, and harmful substances.

• Thermoregulation: Regulates body temperature through sweat production and blood flow.

• Sensation: Contains sensory receptors for touch, pain, temperature, and pressure.

• Excretion: Eliminates waste products through sweat.

• Vitamin D Synthesis: Initiates the production of vitamin D when exposed to UV light.

Types of Glands

• Sudoriferous (Sweat) Glands: Produce sweat for cooling and excretion. Two types: eccrine (widely distributed, regulate temperature) and apocrine (armpits, groin, active at puberty).

• Sebaceous Glands: Secrete sebum (oil) to lubricate skin and hair.

• Ceruminous Glands: Found in the ear canal, produce earwax.

• Mammary Glands: Modified sweat glands that produce milk.

Tissues in the Dermis

• Dense Irregular Connective Tissue: Provides strength and elasticity.

• Areolar Connective Tissue: Supports blood vessels and nerves.

Pigments in the Epidermis

• Melanin: Brown-black pigment produced by melanocytes; protects against UV radiation.

• Carotene: Yellow-orange pigment from diet; accumulates in stratum corneum and fat.

• Hemoglobin: Red pigment in blood; gives skin a pinkish hue when oxygenated.

Properties and Locations of Skin Layers

• Epidermis: Outermost layer; stratified squamous epithelium; avascular.

• Dermis: Middle layer; contains connective tissue, blood vessels, nerves, glands, and hair follicles.

• Hypodermis (Subcutaneous Layer): Deepest layer; composed of adipose and areolar tissue; insulates and anchors skin.

Skeletal System

Anatomy and Function of Osteons

• Osteon (Haversian System): Structural unit of compact bone; consists of concentric lamellae around a central canal.

• Central (Haversian) Canal: Contains blood vessels and nerves.

• Lacunae: Small spaces housing osteocytes.

• Canaliculi: Tiny channels connecting lacunae for nutrient/waste exchange.

Bone Types

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

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

• Flat Bones: Thin, flat (e.g., sternum).

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

• Sesamoid Bones: Develop within tendons (e.g., patella).

Types of Motion

• Flexion/Extension: Decreasing/increasing angle between bones.

• Abduction/Adduction: Movement away from/toward midline.

• Rotation: Bone turns around its own axis.

• Circumduction: Circular movement combining flexion, extension, abduction, and adduction.

Types and Properties of Joints

• Fibrous Joints: Immovable (e.g., sutures of skull).

• Cartilaginous Joints: Slightly movable (e.g., intervertebral discs).

• Synovial Joints: Freely movable; contain synovial fluid (e.g., knee, shoulder).

Functions of the Skeletal System

• Support

• Protection

• Movement

• Mineral storage (calcium, phosphate)

• Blood cell production (hematopoiesis)

• Triglyceride storage

Key Features of Male/Female Pelvic Girdles

• Male Pelvis: Narrower, heavier, more vertical; pubic arch angle < 90°.

• Female Pelvis: Wider, lighter, more shallow; pubic arch angle > 90°; adapted for childbirth.

Characteristics/Parts of Long Bones

• Diaphysis: Shaft; contains medullary cavity.

• Epiphyses: Ends; contain spongy bone and red marrow.

• Metaphysis: Region between diaphysis and epiphysis; contains growth plate.

• Periosteum: Outer covering; contains nerves and blood vessels.

• Endosteum: Lines medullary cavity.

Properties of Spongy Bone

• Composed of trabeculae (lattice-like network).

• Contains red bone marrow for hematopoiesis.

• Found in epiphyses of long bones and inside flat bones.

Muscular System

Where ACh is Found in Muscles

• Acetylcholine (ACh): Neurotransmitter released at the neuromuscular junction; binds to receptors on the muscle fiber's motor end plate to initiate contraction.

Functions, Parts, and Borders of Sarcomeres

• Sarcomere: Functional contractile unit of muscle fiber; extends from one Z line to the next.

• Transverse (T) Tubules: Invaginations of the sarcolemma; transmit action potentials into the muscle fiber.

• Myofibrils: Bundles of actin and myosin filaments within muscle fibers.

• Z Lines: Define boundaries of each sarcomere.

Parts of Whole Muscles

• Muscle Fiber: Single muscle cell.

• Fascicle: Bundle of muscle fibers.

• Epimysium: Surrounds entire muscle.

• Perimysium: Surrounds fascicles.

• Endomysium: Surrounds individual muscle fibers.

Muscle Functions

• Movement

• Posture maintenance

• Joint stabilization

• Heat generation

Why Skeletal Muscles Appear Striated

• Due to the regular arrangement of actin and myosin filaments in sarcomeres, creating alternating light (I bands) and dark (A bands) bands.

Central Nervous System (CNS)

Functions of Neurons and Their Parts

• Neuron: Basic functional unit of the nervous system; transmits electrical impulses.

• Dendrites: Receive signals from other neurons.

• Cell Body (Soma): Contains nucleus and organelles.

• Axon: Conducts impulses away from the cell body.

• Axon Terminals: Release neurotransmitters to communicate with other cells.

What Comprises the CNS

• Brain

• Spinal cord

Efferent vs Afferent Divisions of the Nervous System

• Afferent Division: Carries sensory information from receptors to CNS.

• Efferent Division: Carries motor commands from CNS to effectors (muscles, glands).

Brain Anatomy and Functions of Different Brain Divisions

• Cerebrum: Higher brain functions (thought, memory, voluntary movement).

• Cerebellum: Coordination and balance.

• Diencephalon: Includes thalamus (sensory relay) and hypothalamus (homeostasis, endocrine control).

• Brainstem: Includes midbrain, pons, medulla oblongata; controls vital functions (breathing, heart rate).

Gray vs White Matter in Spinal Cord and Brain

• Gray Matter: Contains neuron cell bodies, dendrites, and unmyelinated axons; site of synaptic integration.

• White Matter: Composed of myelinated axons; responsible for transmission of signals.

Meninges in the Spinal Cord and Brain

• Dura Mater: Tough, outermost layer.

• Arachnoid Mater: Middle, web-like layer.

• Pia Mater: Delicate, innermost layer adhering to brain/spinal cord surface.

Peripheral Nervous System (PNS)

Postganglionic Fibers of the Parasympathetic Division

• Postganglionic fibers are cholinergic (release acetylcholine) and are typically short, targeting specific organs for rest-and-digest responses.

Sympathetic vs Parasympathetic Responses

Sympathetic	Parasympathetic
"Fight or flight"	"Rest and digest"
Increases heart rate	Decreases heart rate
Dilates pupils	Constricts pupils
Inhibits digestion	Stimulates digestion

Ascending vs Descending Pathways

• Ascending Pathways: Sensory tracts carrying information to the brain.

• Descending Pathways: Motor tracts carrying commands from the brain to effectors.

Components and Correct Order of a Reflex Arc

1. Receptor

2. Sensory neuron

3. Integration center (CNS)

4. Motor neuron

5. Effector

General and Special Senses

Receptor Types

• Mechanoreceptors: Detect touch, pressure, vibration.

• Thermoreceptors: Detect temperature changes.

• Photoreceptors: Detect light (in the eye).

• Chemoreceptors: Detect chemicals (taste, smell).

• Nociceptors: Detect pain.

Eye Structures and Functions

• Cornea: Transparent, refracts light.

• Iris: Controls pupil size.

• Lens: Focuses light on retina.

• Retina: Contains photoreceptors (rods and cones).

• Optic Nerve: Transmits visual information to brain.

Layers of the Eye

• Fibrous Tunic: Sclera and cornea.

• Vascular Tunic (Uvea): Choroid, ciliary body, iris.

• Nervous Tunic: Retina.

Properties of Eye Humors

• Aqueous Humor: Clear fluid in anterior chamber; nourishes lens and cornea.

• Vitreous Humor: Gel-like substance in posterior chamber; maintains eye shape.

Types of Eye Cones

• S-cones: Sensitive to short wavelengths (blue).

• M-cones: Sensitive to medium wavelengths (green).

• L-cones: Sensitive to long wavelengths (red).

Properties of Eye Cavities

• Anterior Cavity: Contains aqueous humor; in front of lens.

• Posterior Cavity: Contains vitreous humor; behind lens.

Ear Structures and Functions

• Outer Ear: Auricle (pinna) and external auditory canal; collects sound.

• Middle Ear: Tympanic membrane and ossicles (malleus, incus, stapes); transmits vibrations.

• Inner Ear: Cochlea (hearing), vestibule and semicircular canals (balance).

Ear Passages

• External auditory canal

• Eustachian (auditory) tube: equalizes pressure

Organ of Corti

• Located in the cochlea; contains hair cells that transduce sound vibrations into nerve impulses.