Divisions of the Nervous System

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Can you think of any parts of the Nervous System?

The Nervous System• Central Nervous System

– Brain– Spinal Cord

• Peripheral Nervous System– Somatic (reflex) Nervous System– Autonomic (involuntary) Nervous System

• Sympathetic• Parasympathetic

Central Nervous SystemBRAIN

• Cerebrum (with cerebral cortex/medulla)– controls conscious activity– Each hemisphere controls opposite side of body

• Cerebellum – back of skull– Controls coordination

• Brainstem – connects brain to spinal cord– 3 parts – medulla oblongata, pons, and midbrain– Controls breathing, heart rate, coughing

• Thalamus and Hypothalamus– Controls hunger, thirst, body temperature

The Brainstem

• Medulla Oblongata: Controls involuntary functions that include breathing, blood pressure, heart rate, etc…

• Pons: Bridge between Cerebellum and Cerebrum

• Midbrain: Involved in hearing and vision

The Cerebellum

• Coordinates and balances the actions of the muscles so body can move gracefully and efficiently.

• What do you think would happen if your cerebellum was damaged?

• Lack of coordination, muscle weakness, difficulty performing simple tasks such as walking

• Important for athletic training

Hypothalamus/Pituitary Gland

• These control visceral functions, body temperature, and behavioral responses such as feeding, drinking, sexual response, aggression, and pleasure

The Cerebrum

• Integrates information from all the sense organs, initiates motor functions, controls emotions, and holds memory and thought processes

• Cerebrum has areas, or lobes which are specialized for specific purposes

The Lobes

• Occipital lobe: Vision

• Parietal lobe: Touch, Spatial

• Frontal lobe: Creativity, Decisions, Muscle Control

• Temporal lobe: Sound, Memory

Brain Damage• What lobe is this nail

located in?

• If this nail did damage to this lobe (which it didn’t), what human functions would be affected?

Central Nervous SystemSPINAL CORD

• Spinal cord– Link between brain and peripheral nervous

system– Controls reflexes

Peripheral Nervous SystemSOMATIC NERVOUS SYSTEM

• Regulates activities under CONSCIOUS control and REFLEXES– Conscious Control: Lifting your finger,

wiggling your toes– Reflexes: stepping on a nail and your leg

pulls your foot back rapidly

Somatic Nervous SystemREFLEX ARC

• Quick, automatic response to a stimulus– Bypasses the brain

• The pathway that a nerve impulse travels to result in a reflex

• Involves a receptor (your toe), sensory neuron, motor neuron, and effector (your leg muscle).

Reflex Arc

Reflex Arc

1. Sensory Receptor - where pain occurs

2. Stimulates sensory neuron

3. Message travels to spinal cord

4. Signal sent to motor neuron

5. Effector - responding muscle

Autonomic Nervous System

• What comes to mind when you say “Autonomic”?

• What do you think it means?

• Can you think of any body functions that are automatic?

Peripheral Nervous SystemAUTONOMIC NERVOUS SYSTEM

• Controls all automatic body activities, for example:– Heart Rate– Hormone Release– Digestion

• Broken Down further into

– Sympathetic Nervous System

– Parasympathetic Nervous System

Autonomic Nervous System

• Sympathetic & Parasympathetic Nervous Systems– Have opposite effects on the same organ

to help maintain homeostasis• Remember the heater example?• What happens when you are too cold or too

hot?• What happens when your body comes back to

a normal temperature?

In Review

• Central Nervous System– Brain

• Cerebrum• Cerebellum• Brainstem• Thalamus & Hypothalamus

– Spinal Cord• Links Brain & Peripheral N.S.• Controls Reflexes

In Review• Peripheral Nervous System

– Somatic

• Conscious Activities & Reflexes–Reflex Arc

–Autonomic• All Involuntary Activities (besides

reflexes)–Sympathetic–Parasympathetic