Nervous Tissue Flashcards
what are the 2 subdivisions of the nervous system?
peripheral and central
what makes up the central nervous system? (2)
brain and spinal cord
what are the 2 divisions of the peripheral nervous system?
autonomic and somatic
what are the 2 divisions of the autonomic nervous system?
sympathetic and parasympathetic
what is the autonomic nervous system used to motor? (3)
- cardiac muscle
- smooth muscle
- glands
what does the somatic nervous system motor?
voluntary skeletal muscle
what is the function of the sympathetic division of the autonomic peripheral nervous system?
active and alert
what is the function of the parasympathetic division of the autonomic peripheral nervous system?
rest and digest
what are the 3 components of the peripheral nervous system?
- cranial nerves
- spinal nerves
- associated nerve roots and ganglia
what components make up the autonomic nervous system?
motor ganglia and the nerves that innervate viscera
what components make up the somatic nervous system?
motor nerves that innervate skeletal muscle
what is nervous tissue composed of?
nerve cells (neurons) and their supportive cells (glial cells)
how are nerve cell bodies (neurons) often found? what are these called in the CNS and PNS?
nerve cell bodies (neurons) are often found in clusters or groups that have common functions;
groups of neurons in CNS: nuclei
groups of neurons in PNS: ganglia
what is a nerve fiber?
a single axon
what is a peripheral nerve?
a bundle of nerve fibers (axons) surrounded by their CT sheaths
what is all nervous tissue surrounded by?
connective tissue
what is an organized collection of axons called in the CNS?
tract
what is an organized collection or axons called in the PNS?
nerve
what 2 types of fibers does every nerve have?
motor and sensory fibers
what are the 2 types of nervous tissue in the CNS?
white matter and grey matter
describe white matter
nervous tissue consisting mainly of axons and their myelin sheaths
describe grey matter
nervous tissue consisting mainly of nerve cells bodies (neurons) and unmyelinated axons (nerve fibers)
what are the 3 basic autonomical classifications of neurons?
- unipolar (pseudounipolar)
- bipolar
- multipolar
describe the structure of unipolar (pseudounipolar) neurons
nerve cell body gives off a single axon that bifurcates into a central and a peripheral branch
what is the function of unipolar (pseudounipolar) neurons?
afferent neurons that convey sensory information TO the CNS
where are unipolar (pseudounipolar) neurons found?
found in sensory ganglia located in specific cranial nerves and in the dorsal roots of all spinal nerves
describe the structure of bipolar neurons
nerve cell body gives off two processes
describe the function of bipolar neurons
like unipolar, are afferent neurons that convey sensory information to the CNS
where are bipolar neurons found (3)/associated with?
associated with special senses, so found in
1. visual retina
2. olfactory epithelium
3. ganglia of vestibulocochlear nerve (used for balance and hearing)
describe the structure of multipolar neurons
nerve cell body gives off many dendrites and an axon
what is the most common type of axon based on anatomical classification?
multipolar
describe the function of multipolar neurons (2)
- are motor neurons that carry signals AWAY from the CNS
- are also interneurons that connect sensory neurons to spinal motor neurons
what are the 3 groups of neurons based on function?
- sensory
- motor
- interneuron
describe sensory neurons
Afferent neurons that transmit sensory impulses TO the CNS
describe motor neurons
Efferent neurons that transmit motor impulses away from the CNS
describe interneurons
neurons that transmit impulses between neurons; connect sensory Afferent neurons to Efferent motor neurons OR with the next neuron in a chain
define neurons (3)
- nerve cells
- the structural and function units of the nervous system
- highly specialized/modified cells which are capable of receiving and transmitting stimuli, often involving sensory transduction
what is sensory transduction?
converting a physical or chemical sensory stimulus into an electric signal that results in neuronal activity