CH 11 Study Guide

Central Nervous System (CNS)

-Brain and Spinal Cord

-Integrative and Control Centers

Peripheral Nervous System (PNS)

-Cranial & Spinal Nerves

-Comm. between CNS and rest of the body

Sensory (afferent) division

-Conducts impulses from receptors to CNS

Motor (efferent) division

-Conducts impulses from CNS to effectors (muscles and glands)

Somatic Nervous System

-Conducts impulses from the CNS to skeletal muscles

Autonomic Nervous System

-Conducts impulses from CNS, to cardiac & smooth muscles, and glands

Sympathetic Division

-Mobilizes body systems during activity

Parasympathetic Division

-Conserves energy

-Promotes house-keeping functions during rest

Astrocytes

-       CNS Support and Ion regulation

Microglial Cells

-       CNS Immune Defense

Ependymal cells

-       CNS Cerebrospinal fluid protection

Oligodendrocytes

-       CNS Myelin production

Satellite Cells (IN PNS)

-       PNS Myelin production and nerve regeneration

Schwann Cells (aka neurolemmocytes)

-       PNS Ganglia microenvironment regulation

Sensory Neurons (Afferent)

-       Function: Carry Signals from sensory organs to the CNS

-       Brings information in

Motor Neurons (Efferent)

-       Transmit signals from the CNS to muscles or glands.

-       Sends instructions out

Graded Potential

-       Variable, localized changes

Action Potential

-       Rapid, all-or nothing signals that travel along the axon

1)    Resting State

-       No ions move through voltage-gated channels

2)    Depolarization

-       Caused by Na+  (Sodium) flowing into the cell

3)    Repolarization

-       Caused by K+  (Potassium) flowing out the cell

4)    Hyperpolarization

-       Caused by K+ Continuing to leave the cell

Refractory Period

-       Time when another action potential cannot be triggered

Absolute Refractory Period

-       No action potential can occur

-       Due to sodium channel inactivation

Relative Refractory Period

-       Action potential possible w/ strong stimulus

-       Some sodium channels recovering not all

Continuous Conduction

-       Unmyelinated Axons

-       Slower Transmission

Saltatory Conduction

-       Myelinated axons with nodes of Ranvier

-       Faster Jumping transmission

Nervous System Synapses Structural Component

-       Presynaptic Terminal

-       Synaptic Cleft

-       Postsynaptic Membrane

Nervous System Synapses Function

-       Transmission of Signals: Information transfer from one neuron to another or to an effector cell (muscle or gland).

2 Different Kinds of Synapses

Chemical: Neurotransmitters

Electrical: Gap Junctions

Acetylcholine

-       Class: Neurotransmitter (Cholinergic)

-       Role: Nerve impulse transmission, muscle contraction, autonomic functions, cognitive processes

Nitric oxide

-       Class: Gasotransmitter

-       Role: Vasodilation, memory, synaptic plasticity

Serotonin

-       Class: biogenic amine

-       Role: Mood regulation, sleep-wake cycles, pain perception

Glycine

-       Class: Amino Acid neurotransmitter

-       Role: Inhibitory neurotransmitter, motor control, spinal reflexes