Nervous System Basics Flashcards
What structures compose the CNS?
The brain and spinal cord
What structures compose the PNS?
The PNS consists of nerve fibers and cell bodies outside the CNS that conduct nerve impulses to and from the CNS
Describe the somatic nervous system (SNS)
The somatic nervous system is the voluntary nervous system. It carries sensation like pain from the skin and position sense from the joints. It also supplies skeletal muscle
Describe the autonomic nervous system
The autonomic nervous system is automatic, involuntary, or visceral. It supplies the smooth muscle, glands, and viscera in the body cavities
If a patient cannot move their leg when they think about moving their leg, what nervous system is affected?
Somatic nervous system in the peripheral system
If a patient cannot vasodilate their blood vessels, what nervous system may be malfunctioning?
The autonomic system
What is a neuron?
Neurons are the basic functional and structural unit of the nervous system. They are designed for rapid communication.
What is myelin made up of and what does it do?
Layers of lipids and proteins. It forms a sheath around some neurons and increases the speed of impulse conduction.
What are neuroglia?
Neuroglia are like the caregivers of neurons. They support, nourish, and insulate the neurons. They are five times as abundant as neurons and are nonneuronal, nonexcitable cells. Neuroglia are like the scaffolding of nervous tissue.
What are the principle roles of the CNS?
The CNS integrates information and performs higher mental functions like thinking and learning. It integrates incoming information and coordinates the incoming and outgoing neural signals.
What is a collection of nerve cell bodies in the CNS called?
A nucleus
What is a tract?
A bundle of nerve fibers (axons) connecting neighboring or distant nuclei of the CNS. Interconnecting fiber tracts make up the white matter.
What makes up the gray matter of the CNS?
Nerve cell bodies. They lie deeper within.
What are the three meninges of the CNS?
Pia mater, arachnoid mater, and dura mater
What surrounds and protects the CNS?
The meninges and cerebrospinal fluid
What do peripheral nerves consist of?
Bundles of nerve fibers, their connective tissue covering, and blood vessels (the vasa nervorum)
What cells does the PNS consist of?
Nerve cell bodies and nerve fibers
What is a neurolemma?
The cell membranes of Schwann cells that immediately surround the axon, separating it from other axons
What does a nerve fiber consist of?
An axon, its neurolemma, and its endoneurium (a connective sheath)
What are the four regions of the spinal cord?
Cervical, thoracic, lumbar, and sacral
It extends from the foramen magnum to spinal level L1-L2
How much of the nervous system does the spinal cord constitute?
Only about 2% of the whole nervous system.
Where do nerve roots emerge?
Nerve roots emerge bilaterally through the intervertebral foramen.
Each spinal nerve segment has a pair of dorsal roots and a pair of ventral roots.
These nerve roots from 31 pairs of spinal nerves.
How many dermatomes does each pair of spinal nerves monitor?
One
How many pairs of cranial nerves are there?
12
