Chapter 12 A&P1

Nervous System & Endocrine System

controls conditions in the body & works to maintain homeostasis

Nervous System Responsibility

behaviors, memories, movements & perceptions

Gray Matter

contains neural cell bodies, dendrites, unmyelinated axons, axon terminals & neuroglia

White Matter

bundles of axons (myelinated/unmyelinated) in the brain & spinal cord

Sensory Function

sense changes in the internal & external environment through sensory receptors

Integrative Function

to analyze the sensory information, store some aspects & make decisions regarding appropriate behaviors

Motor Function

respond to stimuli by initiating action

2 Main Nervous System Subdivisions

• The central nervous system (CNS)

• The peripheral nervous system (PNS)

Most Neurons have….

• a cell body

• an axon

• dendrites

• axon terminals

Nerve Fiber

the entire structure (every part) is considered a….

Dendrites & Cell Bodies

contains organelles & Nissl bodies

Nucleus of Shwann Cell

constrain cytoplasm & a myelin sheath wrapped around the nuerolemma

Structural Classification of Nuerons

based on the number of processes (axons or dendrites) extending from the cell body

Bipolar Neuron

Has ONE main dendrite and ONE main axon

Meissner Corpuscle

touch receptor, enclosed in a capsule

Merkel/Tactile Disc

tactile/touch receptor, free nerve ending

Pacinian Corpuscle

pressure receptor, multilayer capsule

Nociceptor

pain receptor, free nerve ending

Schwann Cells

form myelin sheaths around axons during fetal development

Factors that Affect Propagation Speed

• amount of myelination

• Axon diameter

• Temperature

Chemical Synapses

neurons do not touch, they release neurotransmitters

Electric Synapses

Impulses conduct directly between plasma membranes of adjacent neurons, creates faster communication & sunchronization

Excitatory

when a neurotransmitter depolarizes the postsynaptic membrane

inhibitory Postsynaptic Potential (IPSP)

Kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential

Action Potential

a short lasting event in which the electrical potential of a cell rapidly rises and falls

CNS

no repairs are possible

PNS

can repair damaged dendrites or axons

Neuronal Circuits involved in many activities…

• movement

• Breathing

• Short term memory

• Waking up