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47 Cards in this Set

  • Front
  • Back
What is the most complex system of the body?
The Nervous System
What ability does it have?
the ability to respond externally and internally
What is the nervous sys. made of?
mainly nerual tissue, also blood vessels and CT
What is neural tissue made of?
neurons and neuroglial cells
structural and functional units of the nervous system specialized to react to physical and chemical changes in their surroundings
What are the three parts of the neuron and its function:
axon-only 1 per cell, carries info away; dendrite-1 or more per cell, carries info to cell; perikaryon-the cell body around nucleus
nerves transmit _____ along _____
nerve impulses; nerve fibers
bundles of nerve fibers, (axons)
Functions of neurogilial cells:
fill spaces, surround, and support neurons, nourishing and sending ane receiving messages
what are axons?
nerve fibers
What are the small spaces between neurons?
What happens at these synapses? what carries it?
impulses cross the synapses,neurotransmitters
molecules that are actual carriers of info
What are the two groups that the organs of the nervous system can be divided into?
Central Nervous System and the Peripheral Nervous System
What is the CNS made of?
brain and spinal cord
What is the PNS made of?
nerves that connect the cns to other body parts
Together these systems provide three general funtions:
sensory, integrative, and motor
How does Sensory work?
There are sensory receptors at the distal ends of peripheral nerves. These gather inro from changes inside and outside the body. These receptors convert their info into nerve impulses. These are transmitted to the CNS from the PNS.
This is where integreation occurs. This means that the impulses are brought together to crete sensations, add to memory or produce thoughts. Afther this happens, couscious or subconscious decisions are made and then acted upon by a motor function.
The motor duncions of the nervous system uses the peripheral neurons to carry impulses to the effectors. These are outside of the nervous system...muscles and glands. These are structures that can respond to nervous stimulation.
What does a perikaryon of a neuron contain?
cytoplasm, mitochondria, lysosomes, neurofibrils and packets of chromatophilic substance once called Nissl bodies (rough ER)
What are the two divisions of the motor portion of the PNS?
somatic ns and autonomic ns
somatic ns?
involved in conscious ancivities (voluntary), suck as skeletal muscle contration
autonomic ns?
controls viscera such as the heart and various glands and therefor controls subconscious (involuntary)action
what extends into the axon and supports them, fine threads?
what is scattered throughouth the cytoplasm that consist of tough er, membranous packets?
chromatophilic substance
what is between the synaptic knob of the axon terminal and the receptive surface?
synaptic cleft
larger axons in the PNS have sheath made of _____ that is a type of _____
Schwann cells; neruoglial cell
what do they do?
tightly wrap around the axon forming the MYELIN SHEATH.
the outer layer of the sheath contains _____ and ____ and is called the ______.
nuclei and cytoplasm and is called the neurilemma sheath
Myelinated nerve fibers are ____ or _____
white fibers, white matter
Unmyelinated nerve fibers are
gray fibers, gray matter
Schwann cell are _____ found ONLY in the ____
neuroglial cells, PNS
What are the narrow gaps in the myelin sheath between Schwann cells?
nodes of Ranvier
what are the types of neuroglial cells?
astrocytes, oligodendrocytes, microglial cells, ependyma
star shaped, the largest and most numerous. They are found between nerve cells and blodd vessels. they function in support and nourishment ...also, respond to injury by froming scar tissue
these function to form the myelin sheath in the CNS
microglial cells-
are very small and functionin phagocytosis of facteria and cellular debris
cuboidal or columnar and may be ciliated. these form a membrane that lones the ventricles of the brain and spinal cord
Regeneration of nerve fibers: If the _____ of a neuron is damaged, the cell usually _____; but if the ____ is damaged the cell may _____.
cellbody; dies; axon; regenerates
In ------ nerves, if the ---- is damaged, the distal end and its myelin sheath ------- within a few weeks
peripheral , axon, disintergratest
----- cells move the debris, leaving a tube made up of ----- and a thin ------ these are remnants of the -----
macrophage, ct, basement membrane, schwann cells
the proximal end of the ---- will develop ------ that grow into the -----
axon; sprouts; tube
the tube will lead the axon back to ----
point of attachment
------ will proliferate along the length of the axon to form a new myelin sheath
schwann cells
regeneration is ----- but may be -----
slow, complete
why is regeneration in the CNS not likely to take place?
dont have schwann cells thus shere is no ct or bm to form a tube to reconnect to the point of attachment