1. Nervous System Ch. 49

2. Nervous System -Found in every part of the body from the head to the tips of the fingers and toes. -Divided into central nervous system (CNS) and peripheral nervous system (PNS). -CNS contains brain and spinal cord. -PNS contains cranial nerves, spinal nerves, and nerves that travel throughout the body.

4. Ch. 49.1 Neurons & Nerve Impulses Neuron Structure: 1. dendrites 2. cell body 3. axon (axon terminals) 4. synapse 5. neurotransmitters

5. Neurotransmitters

6. Nerve Impulses Neuron function is dependent upon electrical activity: Resting Potential Action Potential (Na + in, K + out) -dendrites or cell body become stimulated. -ATP driven sodium-potassium pump re-establishes equilibrium (restores the ions to be ready for another action potential)

7. Ch. 49.2 Structures of the Nervous System

8. Brain Function Structure: 1. Cerebrum two cerebral hemispheres cerebral cortex…sensory processing and motor responses. corpus callosum…heavy band of nerves; connects the two hemispheres white matter…contains axons of cortical neurons.

9. Lobes of the Brain: Frontal: intellectual function Parietal: motor and sensation Temporal: taste & hearing Occipital: vision Cerebellum: balance & coordination

10. Diencephalon 1. thalamus (directs incoming sensory signals to the proper region of the cerebral cortex) 2. hypothalamus (maintains homeostasis, hormone production) Limbic System: structures within the brain that control emotions, memory, and motivation.

11. 3. Brain Stem : (links cerebrum with the spinal cord) 1. midbrain (relay center for visual & auditory information) 2. pons (relay center between cerebral hemispheres and the cerebellum ) 3. medulla oblongata (heart rate and respiration) -reticular formation (network of neurons helping to control respiration and circulation and serves as a filtering system for incoming sensory signals.

12. 4. cerebellum: (coordination of muscle activity) 5. spinal cord: sensory neurons motor neurons interneurons

13. Divisions of the Nervous System Central Nervous System Peripheral Nervous System brain and spinal cord Somatic NS Autonomic NS Regulates activities that are automatic Regulates activities under conscious control Parasympathetic – slows down activities Sympathetic – Speeds up activities Sensory Motor

14. Peripheral Nervous System -afferent neurons (towards)…what we call sensory neurons. -efferent neurons (away)…what we call motor neurons. Two divisions: Sensory and Motor.

15. Division 1: Sensory -contains sensory receptors (nerves) and interneurons that connect them to the brain.

16. Division 2: Motor -Composed of two independent systems: 1. Somatic Nervous System -controls skeletal muscles -reflexes -mainly voluntary, but can be involuntary.

17. 2. Autonomic Nervous System -Controls smooth muscles in blood vessels and organs; respiration, heartbeat and other homeostatic functions -Two Divisions: 1. Sympathetic (stress…moves blood to appropriate organs based upon the stressor. 2. Parasympathetic (normal)

18. Ch. 49, section 3: Sensory Systems Mechanoreceptors Photoreceptors Chemoreceptors Thermoreceptors Pain receptors Main sense organs: eyes, ears, nose, mouth & skin