Divisions of the Nervous System 35-3

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 System BRAIN 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 System SPINAL CORD Spinal cord –Link between brain and peripheral nervous system –Controls reflexes

Peripheral Nervous System SOMATIC 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 System REFLEX 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

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 System AUTONOMIC 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