2.2 Nervous System

1. Neuroanatomy:

• Neuron Structure: Composed of dendrites (receive impulses), soma/cell body (contains nucleus), and axon (sends impulses).

• Synapse: The connection between neurons where chemical neurotransmission occurs (e.g., acetylcholine for muscle contraction).

• Function: Neurons transmit electrical/chemical signals for behavior and body functions.

2. Brain:

• Cerebrum: Controls higher functions like speech, reasoning, and voluntary movements; divided into left (language, arithmetic) and right (creativity, spatial skills) hemispheres.

• Cerebellum: Coordinates muscle movements, posture, and balance.

• Brainstem: Regulates automatic functions like breathing and heart rate; includes the midbrain, pons, and medulla.

3. Lobes of the Brain:

• Frontal Lobe: Handles personality, emotions, problem-solving, and voluntary movements.

• Parietal Lobe: Processes sensory input and spatial awareness.

• Occipital Lobe: Responsible for vision.

• Temporal Lobe: Manages hearing, memory, and language comprehension.

4. Spinal Column:

• Sections: Cervical (C1–C7), Thoracic (T1–T12), Lumbar (L1–L5), Sacral (S1–S5), Coccyx (3–4 fused).

• Injuries:

  • C1–C4: Severe paralysis, may require ventilators.

  • C5–C8: Varying abilities with arms/hands; may use adaptive equipment.

  • T1–T12: Paraplegia; arm functions normal; may walk with braces.

  • L1–S5: Some leg/hip dysfunction; bowel/bladder control impacted.

5. Peripheral Nervous System (PNS):

• Structure: Includes cranial/spinal nerves; links CNS to the body.

• Motor Systems:

  • Somatic: Controls voluntary muscle movements.

  • Autonomic: Manages involuntary activities; includes sympathetic (fight-or-flight), parasympathetic (rest-and-digest), and enteric (digestive).

6. Cranial Nerves (12 total):

1. Olfactory: Smell.

2. Optic: Vision.

3. Oculomotor: Eye movement, pupil constriction.

4. Trochlear: Eye muscle control.

5. Trigeminal: Sensory (face) & motor (chewing).

6. Abducens: Lateral eye movement.

7. Facial: Facial expressions; taste.

8. Vestibulocochlear: Balance and hearing.

9. Glossopharyngeal: Swallowing; taste.

10. Vagus: Heart, digestion, voice.

11. Spinal Accessory: Shoulder/neck movement.

12. Hypoglossal: Tongue movement.

Multiple Choice Quiz

Questions:

1. Which part of a neuron sends impulses to other neurons?

   • A. Dendrites

   • B. Soma

   • C. Axon

   • D. Synapse

2. What function does the cerebellum perform?

   • A. Regulates heartbeat and breathing

   • B. Coordinates balance and movement

   • C. Interprets sensory signals

   • D. Controls higher reasoning

3. What is the largest part of the brain?

   • A. Cerebellum

   • B. Brainstem

   • C. Cerebrum

   • D. Spinal Cord

4. What spinal nerves are responsible for elbow extension and finger movement?

   • A. C1–C4

   • B. C7

   • C. T1–T5

   • D. L1–L5

5. Which autonomic system prepares the body for "fight or flight"?

   • A. Parasympathetic

   • B. Sympathetic

   • C. Somatic

   • D. Enteric

6. Which cranial nerve is responsible for facial expressions?

   • A. Trigeminal

   • B. Facial

   • C. Abducens

   • D. Hypoglossal

7. The occipital lobe is primarily responsible for:

   • A. Language comprehension

   • B. Vision

   • C. Touch and temperature

   • D. Problem-solving

8. What type of injury is associated with complete paralysis of arms, legs, and trunk?

   • A. Thoracic

   • B. Sacral

   • C. High-Cervical

   • D. Lumbar

Answer Key:

1. C. Axon

2. B. Coordinates balance and movement

3. C. Cerebrum

4. B. C7

5. B. Sympathetic

6. B. Facial

7. B. Vision

8. C. High-Cervical

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