Nervous System Flashcards
Structural division of the nervous system
CNS (brain and spinal chord) and PNS (everything else)
Functional division of nervous system
Somatic nervous system and autonomic nervous system
Two types of cells in nervous tissue
Neurons (nerve cells) neuroglia cells (glial cells for support)
Neurons are specialized for
rapid communication
A neuron is composed of a ___ with processes called ____ and an ____ that carry impulses.
cell body, dendrites, axon
Myelin
sheath around axons that increases impulse transmission. Lipid
Two types of neurons
Multipolar motor neurons and pseudo unipolar sensory neurons
Multipolar neurons
two or more dendrites and. single axon that can have more than one collateral branch **MOST COMMON IN CNS AND PNS
Pseudounipolar sensory neurons
short and apparently single process extending from the cell body The common process then separates
all the motor neurons that control skeletal muscle and those comprising the ANS are ___ neurons
multipolar
The common process of pseudounipolar sensory neurons separates into
a peripheral process (from receptors on organs to the cell body) and a central process (continues from the cell body to the CNS).
Where are the cell bodies of pseudonipolar neurons located? What are they part of?
outside the CNS in sensory ganglia. Part of the PNS
Where and how to neurons communicate
at the synapse by the release of NT which can either excite of inhibit another neuron
Neuroglia
five times more abundant than neurons. non-excitable cells, that help with supporting, insulating and nourishing the neurons
In the CNS, neuroglia include
oligodendrogia, astocytes, ependymal cells, microglia
Neuroglia cells in the PNS include
satellite cells (posterior root), and Schwann Cells (autonomic ganglia)
CNS
brain and spinal cord, its function is to integrate and coordinate signals both incoming and outgoing and then carry out higher functions.
Nucleus
collection of nerve bodies in the CNS
tract
bundle of nerve fibers or axons
grey matter
where nerve cell bodies are
white matter
interconnecting fiber tract systems
Grey matter appearance
looks like an H producing horns (L and R anterior (ventral) and posterior (dorsal) horns)
What protects the CNS
the meninges and the CSF
The meninges
the Pia mater (thin innermost layer), [CSF GOES HERE] arachnoid mater and the dura mater (thick outermost layer)
Dura mater in the brain vs the spinal cord
in the brain, the dura mater touches the skull or the brain case. In the spinal cord, the dura mater does not touch bone, it is separated by the epidural space.
PNS
nerves connect the CNS to peripheral structures. Its role is to carry impulse to and from the CNS
Nerve fiber
nerve fiber, neurolemma (cell membranes of Schwann cells that surround the axon) and endoneurual connective tissue
Nerolemma
cell membranes of the Schwann cells that immediately surround the axon
Neurolemma can take two forms
- myelinated nerve fiber has Schwann cells specific to an individual axon, set in a series of enwrapping cells to form myelin
- unmyelinated: multiple axons are separately embedded in the cytoplasm of the cellThese Schwann cells o not produce myelin
Components of a nerve
- a bundle of nerve fibers outside of the CNS
- the CT that surround and bind the the nerve fibers together
- Blood vessels that nourish the nerve fibers
Nerve fiber connective tissue coverings
- Endoneurium: delicate innermost layer
- Perineurium: dense layer of CT that encloses a fascicle of nerve fibers. Provides protection
- Epineurium: thick layer that encompasses a group of fascicles. Fatty tissue, blood vessels and lymph
Ganglion
a collection of nerve cell bodies outside of the CNS
Afferent (sensory) fiber
Carries impulses from sensory organs like the eyes and receptors to the CNS
Efferent (motor) fibers
Carry impulses from the CNS to the effector organs
Cranial nerves
ext cranial cavity through foramina. ID’d by either their descriptive name of a roman numeral
How many pairs of cranial nerves arise from the brain, and how many arise from the spinal cord
11 pairs from the brain, and one from the superior part of the spinal cord
Spinal (segmental) nerves
exit the vertebral column through intervertebral foramina. they arise in pairs from specific segments of the spinal cord
How many pairs of spinal nerves are there? and how are they identified
By letter and number, like C6 and there are 31 pairs