Unit 9.3 - Neurological System

Nervous System Structure

Central Nervous System - brain & spoinal cord (contains upper motor neurons).

Peripheral Nervous System - all nervous tissue outside of CNS; spinal nerves & cranial nerves (contains lower motor neurons).

Crossed Representation - left side of brain communicates with right side of body and vice versa.

Nervous System Function

Sensory - detect stimuli (various senses).

Integrative - process information (speech, memory, emotions and thoughts).

Motor - activation of msucles and glands (control body movements, regulates internal organs).

Central Nervous System

Brain: cerebrum (hemispheres, cerebral cortex, basal ganglia), thalamus and hypothalamus, cerebellum, brain stem.

Spinal Cord

Cerebrum

“seat of intelligence”

Cerebral Cortex Lobes: frontal (voluntary movement, “who we are", contains Broca’s area), parietal (primary sensation center, awareness of our body), occipital (primary visual receptor center), Temporal (primary auditory center, contains Wernicke’s area).

Deep Brain Structures

Basal Ganglia - controls automatic movements.

Thalamus - major relay station.

Hypothalamus - “hub between mind and body”, regulates hormones, temperature, appetite, pain/pleasure, emotion, sleep/wake cycle, etc.

Lower Brain Structures

Cerebellum - blends skilled movements & posture and balance.

Brain Stem - midbrain (connects spinal cord to thalamus), pons (ascending/descending fibre tracts), medulla oblongata (vital centres: ht rate, breathing; and others: vomiting, hiccuping, coughing sneezing).

Spinal Cord - “main pathway”, grey matter (site of integration), white matter (dozens of sensory and motor tracts).

Sensory and Motor Pathways

Sensory Pathways: spinothalamic (pain, temperature, crude touch), posterior dorsal columns (vibration, stereognosis, proprioception).

Motor Function: pyramidal (direct, skilled, purposeful movement), extrapyramidal (indirect movement), cerebellar (movement, equilibrium, posture).

Peripheral Nervous System

1. Somatic Nervous System (voluntary)

2. Automatic Nervous System (involuntary)

   1. Sympathetic = “flight or flight”

   2. Parasympathetic = “rest and digest”

3. Enteric Nervous System (brain of the gut)

Reflexes

Deep Tendon (Stretch) - done by stretching buscle (e.g., knee jerk).

Superficial (Cutaneous) - done by stimulating the surface of the body (e.g., abdominal).

Visceral (Autonomic) - acts on smooth muscle (e.g., pupillary).

Pathological (abnormal) - present when there is injury to the spinal cord (e.g., Babinski)

Cranial Nerves

Medical Terms

Clonus - involuntary contractions and relaxations.