The Nervous System (Structural/Functional)

Chapter 14

What is the structural organization of the central nervous system?

brain, spinal cord

What is the structural organization of the peripheral nervous system?

cranial nerves, spinal nerves, ganglia

What is the functional organization of the nervous system?

first = collecting information, second = passing and evaluating information, third = responding to information

The central nervous system initiates nerve impulses to what? These things react to changes in the body’s environment.

effectors

Is the sensory nervous system an affector or an effector?

affector

How does an affector move?

towards the nervous system

Is the motor sensory system an affector or effector?

effector

How does an effector move?

away from the nervous system

What does the sensory nervous system do?

transmits information from receptors to the CNS

What sensory nervous system receives sensory information from skin, fascia, joints, skeletal muscle, and special senses?

somatic sensory

What sensory nervous system receives sensory information from viscera (soft internal organs in the body)?

visceral sensory

What is the motor nervous system that sends voluntary signals to skeletal muscle?

somatic motor

What is the motor nervous system that sends involuntary (automatic( signals to cardiac muscle, smooth muscle, and glands?

visceral motor

What cells within the nervous system are electrically excitable and can initiate, transmit, and receive nerve impulses?

neurons

What cells within the nervous system are non-excitable and support and protect neurons?

glial cells

How much of the nervous system do glial cells make up?

90%

What is the structural unit of the nervous system and is responsible for conducting nerve impulses throughout the body?

neuron

What are the three special characteristics of a neuron?

high metabolic rate, extreme longevity, non-mitotic

What is the cell body of a neuron called?

soma

What does the soma contain a high concetration of?

mitochondria

What is the rough endoplasmic reticulum and free ribosomes in a neuron?

Nissl bodies

What are the short branches that receive impulses and transmit them to the soma?

dendrites

What is singular and carries the impulse from the soma to other cells?

axon

What is the area where the axon attaches to the soma called?

axon hillock

After leaving the soma, an axon may branch into what?

axon collaterals

What is the fine terminal extensions that the axon and its collaterals branch into?

axon telondendria

What are the expanded regions found at the tips of telodendria?

synaptic knobs

What type of neuron branches like a T, where the T-branch is found in a ganglia, and forms the somatic sensory system that transmits information from the external environment to the CNS?

unipolar neuron

What type of neuron contains multiple dendrites and a single axon (the axon may branch into collateral axons), and it is found in the CNS and PNS?

multipolar

What special type of multipolar neuron is found only in the CNS and connects unipolar neurons to multipolar neurons or multipolar neurons to other multipolar neurons?

interneuron

What glial cells in the CNS form the blood brain barrier?

astrocytes

What glial cells in the CNS convert plasa into cerebrospinal fluid?

ependymal cells

What glial cells in the CNS phagocytize dead cells and bacteria?

microglial cells

What glial cells in the CNS myelinate the axons of myelinated neurons in the CNS? (mainly only need one due to its multiple projections)

oligodendrocytes

What glial cells in the PNS surround and protect the soma of unipolar neurons in ganglia?

satellite cells

What glial cells in the PNS myelinate the axons of myelinated neurons in the PNS? (usually need multiple since it can only myelinate one axon)

neurolemmocytes

What is made up of multiple axons arranged in the form of a cable?

nerve

What nerve wrapping is the deepest and surrounds each axon unless the axon is surrounded by myelin sheath (in which case it will surround the myelin sheath)?

endoneurium

What type of connective tissue does endoneurium contain?

areolar connective tissue

What nerve wrapping is in the middle and surrounds a collection of axons (fascicles)?

perineurium

What type of connective tissue does perineurium contain?

dense irregular connective tissue?

What nerve wrapping is the outermost covering of the nerve and surround multiple fascicles?

epineurium

What type of connective tissue does epineurium contain?

dense irregular connective tissue

What type of synapse occurs between cells that are joined by gap junctions, allowing for rapid, smooth contraction of tissue like in the cardiac muscle found in the myocardium?

electrical synapse

What type of synapse forms the junction between a nerve and another neve, skeletal muscle, smooth muscle, and/or glands?

chemical synapse

In a chemical synapse, the axon terminal (nerve) does NOT come into contact with the next structure. What is the space that separates the two?

synaptic cleft