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Chap12 nervous
nervous tissue
Question | Answer |
---|---|
the ____ system along with the _____ helps to keep controlled conditions within limits that maintain helath and helps to maintain homeostasis | nervous, endocrine |
nervous has 3 basic functions | - sensing changes with sensory receptors-interpreting and remembering those changes- reacting to those changes with effectors |
a _____ is a bundle of hundreds or thousands of axons, each which courses along a defined path and serves a specific region of the body | nerve |
spinal cord connects to the ____ through the _____ _____ of the skull and is encircled by the bones of the vertebral column | brain; foramen magnum |
____ is located outside the brain and the spinal cord, are small masses of nervous tissue containing primarily cell bodies of neruons | ganglia |
entric _____ help regulate the digestive system | plexuses |
____ _____ are either parts of neruons or specialized cells that monitor changes in the internal or external enviroment | sensory receptors |
the ____ function is to analyze the sensory info., store some aspects and make decisions reguarding appropriate behaviors. (association or interneurons serve this function) | integrative |
the ____ function is to respone to stimului by initiating action | motor |
CNS | brain/ spinal |
PNS | -cranial/ spinal nerves (sensory & motor)-connects CNS to muscles, glands and all sensory receptors |
motor neurons to skeletal muscles | somatic (voluntary) SNS |
neurons from cutaneous and special sensory receptors to CNS | SNS |
sensory neurons from visceral organs to CNS | autonomic (involuntary) nervous system |
motor neurons to smooth and cardiac mucles and glands (symp/parasymp) | ANS |
involuntary sensory and motor neruons control GI tract | enteric nervous system |
______ neurons of the ENS monitor chemical changes within the GI tract and streching of its walls | sensory neruons |
consists of neurons in enteric plexuses that extend the length of the GI tract | enteric nervous system |
enteric motor neurons govern contraction of GI tract organs, and acticity of the GI tract endocrine cells | enteric motor neruons |
functional unit of nervous system | neuron |
capacity to pro. action potenial/ electical excitability | neruons |
cell body contains nissl bodies(chromatin) what do they do | pro. rough ER and free ribosomes for protein synthesis |
____ give cell shape and support | neruofilaments |
___ move material inside cell | microtubules |
cell processes= | dendrites and axons |
___ are the recieving or input portions of a neuron (carry action potential toward soma) | dendrites |
conducts nerve impules from the neuron to the dendrites or cell body of another neuron or to an efffect organ of the body (muscle or gland) | axon |
typically short, highly branched and unmyelinated | dendrites |
conduct impules away from cell body | axons |
long, thin cylindrical process of cell | axon |
in axons they arise where? | axon hillox |
swollen tips called synapic end bulbs contain vesicles filled with | neurotransmitters |
cell body is location for most | protein synthesis |
slow axonal flow | movement in one direction only- away from cell body |
fast axonal flow | moves organelles & materials along surface of microtubules; either direction |
most neurons in body are | interneurons |
sveral dendries and one axon- most common type of cell | multipolar |
one main dendrite and one axon | bipolar |
bipolar are found where | near retina, inner ear and olfactory |
one process only (develops from a bipolar) | unipolar |
unipolar are always | sensory neurons |
transport sensory info from skin, muslces, joints, sense organs and viscera to CNS | sensory (afferent) neurons |
send motor nerve impules to mucles and glands | motor (efferent) neurons |
connect sensory to motor neurons- 90% of neurons in body | interneurons(association) neurons |
half of the volume of the CNS/ smaller cells than neurons | neuroglial cells |
these cells can divide- rapid mitosis in tumor formation (gliomas) | neuroglial cells |
star- shaped cells/ form BBB by covering blood capillaries | astrocyte |
metabolize neurotrasmitter/ reg. potassium balance/ provide structural support | Astrocytes |
small cells found near blood vessels/ phagocytic role- clear away dead cells | microglia |
form epithelial membrane lining cerebral cavities and central canal of spinal cord | ependymal cells |
produce CSF | ependymal cells |
derived from cells that also gave rise to macrophages and monocytes | microglia |
support neurons in the PNS ganglia | satellite cells |
flat cells surrounding neuronal cell boides in peripheral ganglia | satellite |
most common glial cell type/ analogous to Schwann cells of PNS | Oligodendocytes |
Each forms myelin sheath around more than one axons in CNS | Oligodendocytes |
a multilayered lipid and protein covering called the myelin sheath | myelinination |
produced by Schwann cells and oligodendocytes surrounds the axons of most neurons | myeliniation |
cells encircling the PNS axons | Schwann cells |
Each cell pro. part of myelin sheath surrounding an axon in the PNS | Schwann cell |
all axons surround by a lipoprotein covering_____ produced by ______ | myelin sheath, Schwann cells |
jelly-roll like wrappings made of lipoprotein | myelin |
Schwann cell _____&______ forms outermost layer of neurolemma with inner portion being the myelin sheath | cytoplasm and nucleus |
_____ myeliniate axons in the CNS | oligodendocytes |
white matter= | myelinated processes (white in color) |
nerve cell bodies, dendrites, axon terminals, bundles of UNmyelinated axons and neuroglia | grey matter |
spinal cord= | gray matter froms an H-shape inner core surrounded by white matter |
thin outer shell of gray matter covers surface and is found in clusters called nuclei inside the CNS | brain |
a ____ is a mass of nerve cell bodies and dendrites inside the CNS | nucleus |
neurons are electically excitable due to the ____ difference across their membrane | voltage |
communicate with two types of electrical signals: | 1. action potention2. graded potential |
potentials that can travel long dis. | action |
potentials that are local membrane changes only | graded |
in living cells, a flow of ions occurs though ____ _____ in the cell membrane | ion channels |
_____ (nongated) channels are always open | leakage |
in leakage cannels, membrane permeablility to ___ is high | K+ |
____ channels open and close in response to a stimulus- results in neuron excitability | gated |
___ ____ channels respond to voltage changes, ligands(chemicals) and mechanical pressure | gated ion channels |
_____ gated channels respond to a direct change in the membrane potential | voltage-gated channels |
respond to a spefici chemical stiumulus | ligand gated channels |
respond to mechianical vibration or pressure | mechanically gated ion channels |
____ ions along inside of cell mem. and ___ ions along outside | neg/ postivie |
potential enegry difference at rest is | -70 |
why does resting potential exist | concentration of ions different inside and outside |