Unit 9: Nervous System Flashcards
what can the nervous system be divided into?
- the central nervous system including the brain and spinal cord.
- the peripheral nervous system which is everything else.
what are the brain and spinal cord contained in?
the brain is contained in the cranial cavity of the skull and the spinal cord is contained within the vertebral cavity of the vertebral column.
how is the peripheral nervous system named?
periphery means beyond the brain and spinal cord.
which of the systems is nervous tissue present in?
it is present in both the cns and pns.
what cells are nervous tissue?
neurons and neuroglial/glial cells.
what are the basics of a glial cell?
support the neurons and their activities.
which is more functionally important: glial or neuron: and what is its structure?
neurons are more functionally important.
- they have a soma or cell body
- they also have extensions called processes: axon and dendrites.
what is an axon?
process of a neuron that carries an electrical signal/action potential away from the cell body towards a target cell.
what is a dendrite?
dendrites are the process of a neuron that extend from the cell body in branches to recieving incoming signals/synapses from other neurons.
what is gray matter and white matter?
- gray matter is the region with many cell bodies and dendrites.
- white matter is the region with many axons.
why is the white matter white?
because axons are insulated by a lipid rich substance called myelin which can appear white.
what does myelin sheath do?
insulation of the axons, makes sure the signal does not disappear, and allows for faster transmission of electrical signals.
nucleus in the nervous system is?
localized collection of neuron cell bodies in the cns
ganglion in the nervous system is?
cluster of neuron cell bodies in the pns
what is a tract?
a bundle of axons found in the cns
what is a nerve?
bundle of axons found in the pns that transmit sensory input and response input to and from the cns
The peripheral nervous system can be further divided into?
- somatic nervous system: control of skeletal muscle/voluntary movements
- autonomic nervous system: control of smooth muscle, cardiac muscle, and glands/involuntary movements usually for the sake of homeostasis.
what is a synapse?
a syanpse is a junction between two neurons and it allows electrical signals/chemical signals to be transmitted from one cell to another.
what does polarity mean in this case?
information flows in one direction.
what is myelin made of?
glial cells.
what is the gap between the axons not covered in myelin called?
mode of ranvier and each specific section of the axon is called the axon segment.
what is the end of the axon and what is it for?
the end of the axon is the axon terminal and each of these end in something called the synaptic end bulb. these bulbs are what make the connection with the target cell at the synapsse.