Nervous System AP BiologyUnit 9 Nervous System Major

Nervous System AP Biology—Unit 9

Nervous System Major Divisions Central Nervous System—brain and spinal cord—contains interneurons and cell bodies of motor neurons �Brain—different parts in charge of different functions Peripheral Nervous System—everything outside of central nervous system

Peripheral Nervous System Motor Sensory movement Somatic From CNS to skeletal senses Autonomic From CNS to smooth muscle and glands Sympathetic Parasympathetic Energy giving—”fight or flight” Energy conserving—back to normal

Peripheral Nervous System

Neurons a. Parts—See Picture b. Types i. Sensory (afferent)—bring information into integrating center (brain and spinal cord) ii. Interneuron—connectors, make-up CNS iii. Motor (efferent)—take information out to effectors (muscles and glands)

Neurons

Action Potential Animation

Action Potential

Saltatory Conduction

Conduction—from 1 neuron to another neuron, muscle, or gland Electrical—action potential passes to next touching neuron—fast and steady Example: Heart Important if fast and steady is needed Synapse is very small and so charge can keep passing down the line

Conduction Chemical—necessary because of synapse a. Synapse—gap between neurons b. Neurotransmitters—chemicals that cause depolarization 1. 2. Excitatory—open Na+ channels in the cell receiving the action potential Inhibitory—open Cl- channels to decrease ability to get action potential

Conduction How Synapses Work Animation

Conduction Acetylcholine—muscle contraction and brain Epinephrine—adrenaline Glutamate—excitatory Glycine—inhibitory GABA—inhibitory Norepinephrine—excitatory for ANS Dopamine—affect sleep, mood, attention, and learning Seratonin—affect sleep, mood, attention, and learning

Reflexes �Reflex—the body’s automatic response to certain stimuli • Spinal cord acts without brain—involuntary • Protects body because it’s rapid

Reflexes