BIO 168 Anatomy and Physiology I: Nervous System and Muscular System Concepts

UNIT #5: NERVOUS SYSTEM [Chapters 13, 14, 15]

Brain and Brainstem (pgs. 490-514, 519-523, 536)

  • Key Terms:
    • Nerve: A bundle of axons (nerve fibers) in the peripheral nervous system.
    • Tract: A bundle of axons in the central nervous system.
    • Ganglion: A cluster of nerve cell bodies in the peripheral nervous system.
    • Nucleus: A cluster of nerve cell bodies in the central nervous system.
  • White and Gray Matter:
    • White Matter: Composed of myelinated axons, found primarily in the deeper tissues of the cerebrum.
    • Gray Matter: Composed of neuronal cell bodies, dendrites, and unmyelinated axons, found on the surface of the cerebrum (cerebral cortex).
  • Cerebral Lobes:
    • Frontal Lobe: Involved in decision making, problem-solving, and control of behavior.
    • Parietal Lobe: Processes sensory information like touch and pain.
    • Temporal Lobe: Involved in memory and auditory information processing.
    • Occipital Lobe: Responsible for visual processing.
  • Key Brain Structures:
    • Thalamus: Relays sensory information to the cerebral cortex.
    • Hypothalamus: Regulates homeostasis and controls the autonomic nervous system.
    • Cerebellum: Coordinates voluntary movements and balance.
    • Midbrain: Involved in vision and hearing pathways.
    • Pons: Connects different parts of the brain and regulates breathing.
    • Medulla Oblongata: Controls vital autonomic functions such as heart rate, breathing, and blood pressure.
  • Meninges: Three protective membranes (dura mater, arachnoid mater, pia mater) surrounding the brain and spinal cord.
    • Dura Mater Extensions: Include dural folds and sinuses.
  • Cerebrospinal Fluid (CSF):
    • Composition: Clear, colorless fluid containing glucose, electrolytes, and proteins.
    • Function: Cushions the brain, provides buoyancy, and removes waste.
    • Production: Produced in the choroid plexus of the ventricles.
    • Circulation: Flows through the ventricles, the subarachnoid space, and is reabsorbed into the bloodstream via arachnoid granulations.

Spinal Cord & Periphery (pgs. 457-486)

  • Spinal Cord Structure and Functions:
    • Acts as the main pathway for transmitting information between the brain and the rest of the body.
  • Tracts:
    • Ascending Tracts (Sensory): Carry sensory information to the brain.
    • Descending Tracts (Motor): Carry motor commands from the brain to the body.
  • Spinal Cord Diagram:
    • Dorsal and Ventral Rami: Branches of spinal nerves that innervate the body.
    • Dorsal Root Ganglion: Contains sensory neurons.
    • Dorsal and Ventral Roots: Dorsal roots carry sensory information, while ventral roots carry motor information.
    • Dorsal and Ventral Horns: Contain neuron cell bodies; dorsal horns contain sensory neurons, while ventral horns contain motor neurons.
    • Receptors: Sensory organs that detect stimuli.
    • Effectors: Muscles or glands that respond to stimuli.
  • Innervation Regions:
    • Dorsal & Ventral rami supply all body regions except the head.
  • Spinal Nerve Pairs:
    • Full/Abbreviated Names: E.g., Cervical (C1-C8), Thoracic (T1-T12), Lumbar (L1-L5), Sacral (S1-S5) with specific exiting locations relative to vertebrae.
  • Spinal Nerve Plexus Structure:
    • Formed from the ventral rami. Major plexuses include:
    • Cervical Plexus: Supplies neck muscles and skin.
    • Brachial Plexus: Supplies arm and hand.
    • Lumbar Plexus: Supplies abdomen and parts of leg.
    • Sacral Plexus: Supplies pelvis and lower limb.
  • Dermatomes:
    • Areas of skin innervated by specific spinal nerve roots, important for diagnosing nerve injury.
  • Reflex Definition:
    • An involuntary response to a stimulus.
  • Classifications of Reflexes:
    • Ipsilateral: Response occurs on the same side as the stimulus.
    • Contralateral: Response occurs on opposite side of the stimulus.
    • Monosynaptic: Involves one synapse (e.g., knee-jerk reflex).
    • Polysynaptic: Involves multiple synapses (e.g., withdrawal reflex).
  • Reflex Arc Components:
    • Receptor: Detects stimuli.
    • Sensory Neuron: Transmits impulse to the spinal cord.
    • Integration Center: Processes information (usually in the spinal cord).
    • Motor Neuron: Carries impulse to the effector.
    • Effector: Performs the response (muscle or gland).
  • Types of Spinal Reflexes:
    • Flexor (Withdrawal) Reflex: Pulls away from harmful stimuli, Ipsilateral.
    • Crossed Extensor Reflex: Balances body by extending opposite limb, often activated alongside flexor reflex.

Autonomic Nervous System (pgs. 540-550, 553)

  • Differences Between Systems:
    • Autonomic Nervous System: Involuntary control, regulates internal organs.
    • Somatic Nervous System: Voluntary control, regulates skeletal muscles.
  • Divisions' Functions:
    • Sympathetic Division: Activates fight or flight response, increases heart rate, dilates pupils.
    • Parasympathetic Division: Rest and digest, decreases heart rate, constricts pupils.
  • Antagonistic Effects:
    • Sympathetic vs. Parasympathetic effects are opposite; e.g., heart rate increases under sympathetic and decreases under parasympathetic.
  • Motor Pathways:
    • Sympathetic: Emerge from thoracic and lumbar regions, ganglia located near spinal cord.
    • Parasympathetic: Emerge from brainstem and sacral regions, ganglia located close to or in target organs.

Laboratory Unit 11: Muscular System (Use lab handouts and pgs. 301-303)

  • Key Terms:
    • Tendon: Connective tissue attaching muscle to bone.
    • Ligament: Connective tissue connecting bone to bone.
    • Aponeurosis: A flat sheet of connective tissue connecting muscles to the parts they act upon.
    • Fascia: Connective tissue that surrounds muscles and organs.
    • Origin: The fixed attachment point of a muscle.
    • Insertion: The movable attachment point of a muscle.
  • Antagonist Muscles:
    • Muscles that oppose the action of another (e.g., biceps vs. triceps).
  • Muscle Actions:
    • Trapezius: Moves, rotates, and stabilizes the shoulder blade.
    • Rectus Abdominis: Flexes the vertebral column and compresses abdominal contents.
    • Deltoid: Abducts arm at shoulder.
    • Gluteus Maximus: Extends and laterally rotates hip.
    • Gastrocnemius: Plantar flexes foot at ankle joint.
    • Gracilis: Adducts thigh and flexes knee.
    • Triceps Brachii: Extends the forearm at the elbow.
    • Tibialis Anterior: Dorsiflexes foot at ankle joint.