nervous system ch. 11 Flashcards
sThree sensory system functions
sensory input, integration, motor output
sensory input
the information gathered by the nervous system
integration
the nervous system processes input and decides what to do
motor output
nervous system activates effector organs (muscles and glands) to cause a response
what are the two parts of the nervous system
central and peripheral nervous system
central nervous system includes
brain and spinal cord
peripheral nervous system includes
cranial nerves, spinal nerves, ganglia
spinal nerves
carry impulses to and from the spinal cord
cranial nerves
carry impulses to and from the brain
two divisions of PNS
sensory (afferent) division, motor (efferent) division
what is the sensory division of the PNS responsible for?
consisting of nerve fibers that carry sensory information from receptors to the CNS
What is the motor division of the PNS responsible for?
transmitting impulses from the CNS to muscles and glands
somatic sensory fibers
convey impulses from skin, skeletal muscles, and joints
visceral sensory fibers
transmit impulses from visceral organs
two sectors of the motor divison
the somatic nervous system and the autonomic nervous system
somatic nervous system is also called
the voluntary nervous system
function of the somatic nervous system
conduct impulses from CNS to skeletal muscles
autonomic nervous system is also called
involuntary nervous system
function of the autonomic nervous system
regulate the activity of smooth muscles, cardiac muscles, and glands
the two principle types of nervous cells
neuroglia (Glial) cells and neruons
function of neuroglia
small cells that wrap and surround delicate neurons
function of neurons
excitable cells that transmit electrical signals
4 neuroglia cell types in CNS
astrocytes, microglial cells, ependymal cells, oligodendrocytes
how can neuroglia be distinguished from neurons
they have a much smaller size and darker staining nuclei
astrocyte function
assists in exchanges between blood capillaries and neurons
microglial cell function
can transform phagocytes in areas of neural damage or inflammation
ependymal cell function
lines the central cavities of the brain and spinal cord
oligondendrocyte function
composes myelin sheaths
2 neuroglia cell types in PNS
satellite cells and schwann cells
location of satellite cells
surrounding neuron cell bodies in the PNS
location of schwann cells
surround all nerves fibers in PNS and form myelin sheaths around thicker nerve fibers
neurons alternate name
nerve cells
characteristics of neurons
extreme longevity, neurons are amitotic, neurons have an exceptionally high metabolic rate
neuron cell body componets
a spherical nucleus ( with conspicuous nucleolus) surrounded by cytoplasm
other name for neuron cell body
perikaryon
the cell body is…
the major biosynthetic center and metabolic center of a neuron
the neuron cell body contains there structures
protein and membrane making machine, cytoskeletal elements (microtubules and neurofibrils), pigment inclusions
where are most neuron cell bodies located
CNS
what are clusters of cell bodies in the CNS called
Nuclei
what are clusters of cell bodies in the PNS called
Ganglia
What components of neurons does the CNS contain
Cell bodies and their processes
what components of neurons does the PNS contain
chiefly neuron processes (cell bodies are in the CNS)
two types of neuron processes
dendrites and axons
dendrite description
short, tapering, diffusely branching extensions
the main receptive input region for neurons
dendrites
function of dendrites
convey messages towards the cell body. Usually not action potentials but rather graded potentials.
axon
neuron process that carries action potentials away from the nerve cell body; efferent process: the conducting portion of a nerve cell
axon hillock
cone-shaped area of the cell body from where the axon arises
a long axon is also called
nerve fiber
nucleus
collection of neuron cell bodies in CNS
ganglion
collection of neuron cell bodies in PNS
tract
bundle of axons in CNS
nerve
bundle of axons in PNS
