Module 5 Flashcards
Three functions of the nervous system
sensory input
integration
motor output
what is integration? Where does it occur?
- incorporates multiple simultaneous signals
- occurs in the brain or spinal cord
what are the two subdivisions of the nervous system
- Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)
the brain and spinal cord are apart of which subdivision of the nervous system
central nervous system (CNS)
cranial nerves, spinal nerves, autonomic nervous system, special sense organs are apart of what subdivision of the nervous system
Peripheral nervous system (PNS)
what do efferent neurons do?
carry signals AWAY from the CNS
what do afferent neurons do?
carry signals TOWARDS the CNS
what are the two principle cell types of the nervous system
- neurons
2. supporting cells
Neurons
- excitable
- transmit rapid electrical signals to other neurons
what are the three parts of a neuronās structure
- cell body
- dendrites
- axon
what are the cytoplasmic processes
dendrites and the axon
what is another name for the cell body
soma
what does the cell body do?
houses the nucleus and other organelles. Functions to transfer electrical signals from the dendrites to the axon
what do the dendrites do?
receive the neuronal signal from other neurons and transfer those signals to the cell body
what is the axon?
only ONE per neuron. Carry the signal from the cell body to the axon terminals, where the signal is then transferred to other neurons or organs
a nerve impulse is _______
unidirectional (only occurs in one direction)
what is the order that a nerve impulse moves through a neuron
dendrites - cell body - axon - dendrites of adjacent neurons OR target organs
how are neurons classified ?
based on the number of cellular processes (dendrites and axon) that extend from the cell body
Pseudounipolar neurons
one cellular process that splits into a dendrite and an axon (general sensory nerves)
Bipolar nerves
one dendrite and one axon, two distinct cellular processes (found in special senses like sight and hearing)
multipolar nerves
multiple dendrites and one axon, three or more cellular processes, number of dendrites is variable (motor neurons)
another name for supporting cells
neuroglia (or glia)
what is the function of supporting cells?
to protect and support neurons, as well as aid in sending signals between neurons to improve communication
what are the four supporting cells of the CNS
- Astrocytes
- Microglia
- Ependymal
- Oligodendrocytes
Astrocytes
- large, star-shaped cells with numerous processes
function of astrocytes
communicate with neurons and blood vessels to maintain the integrity of the neural tissue
which of the glial cell sin the CNS is the most abundant?
Astrocytes
Microglia
- perform many protective functions in the CNS
- able to phagocytose (engulf and destroy other cells)
what shape is ependymal?
simple cuboidal
where is ependymal found?
lines the cavities of the brain and spinal cord
which supporting cell assists int he production, circulation and monitoring of cerebrospinal fluid (CSF)?
Ependymal
Oligodendrocytes
- wrap around axons in the CNS to form myelin sheath
- a single cell can myelinate up to 60 axons
what is myelin made up of?
mainly fat, appears white
purpose of myelin?
insulates the axon and increases the speed electrical signals can travel down the axon
neurofibril nodes are what?
unmyelinated regions
What are the supporting cells of the PNS called?
SCHWANN CELLS
what are Schwann cells?
equivalent to the Oligodendrocytes in that they form the myelin sheath around axons in the PNS
A single Schwann cellā¦
can only myelinate a portion of one axon, as they donāt have processes like oligodendrocytes
the cerebrum is made up of what two parts?
Diencephalon and Telencephalon
Diencephalon
- deep to the telencephalon
- responsible for sensory and motor relay into and out of the brain
- controls the autonomic nervous system
what are the two components of the diencephalon?
hypothalamus and the thalamus
what does the hypothalamus do?
controls the release of hormones
where is the hypothalamus located?
- small structure below the thalamus
- connected to the pituitary gland
structure of the thalamus?
- deep brain structure
- two bodies (one per hemisphere)
responsibilities of the thalamus
relaying sensory information to other areas of the brain (except smell)