Nerve Cell Flashcards

  1. What does the word “innervates” mean?
/ Refers to a nerve supplying a muscle or organ. For example, “The phrenic nerve innervates the diaphragm muscle”.
  1. 3 parts of the Nervous System
/
  1. Central Nervous System (CNS): brain and spinal cord.
  2. Peripheral Nervous System (PNS): nerves of the body
  3. Autonomic Nervous System (ANS): has parts of the CNS and PNS.

  1. What are the two parts of the CNS?
/ Brain and Spinal cord
  1. What does the Autonomic Nervous System control and what are its 2 divisions?
/ Controls autonomic function (blood pressure, digestion, etc).
  1. Sympathetic division
  2. Parasympathetic division

  1. What kinds of neurons enter the CNS?
/ Sensory (afferent) signals picked up by sensor receptors. They are carried by nerve fibers of PNS to the CNS
  1. What kind of neurons leave the CNS?
/ Motor (efferent) signals are carried away from the CNS. They innervate muscles and glands
  1. What sheath covers the axon (not referring to myelin)?
/ Endoneurium
  1. What sheath covers a fascicle (bundle of neurons)
/ Perineurium
  1. What sheath covers a bunch of fascicles?
/ Epineurium
  1. What is the neurilemma?
/ Outermost covering of a neuron (plasma membrane)
  1. What is movement of nutrients, wastes, and organelles between the cell body and axon terminals
/ Axoplasmic transport
  1. What three things do all neurons do?
/
  1. Receive a signal. Can be any type of stimulus (change in environment, signal from another neuron, etc).
  2. Transmit a signal to another location. E.g. finger touching something  signal to spinal cord or brain.
  3. Stimulate another cell
  4. Another neuron  transmit signal
  5. Muscle  contraction
  6. Gland  secretion

  1. What three characteristics do all neurons share?
/ 1.Longevity – can live and function for a lifetime
2.Do not divide – fetal neurons lose their ability to undergo mitosis (the y lose their centrioles); neural stem cells are an exception
3.High metabolic rate – require abundant oxygen and glucose
  1. Picture of Sensory vs Motor Neurons
/
  1. Photo of NEURON anatomy
/
  1. What receives the signal and carries the nerve conduction toward the cell body?
/ DENDRITES
  1. Where are the nucleus, ribosomes, and most organelles located?
/ The CELL BODY
  1. What has the function of transmitting signals from the cell body to the area with neurotransmitters?
/ AXON
  1. What part of a neuron stimulates another cell?
/ SYNAPTIC KNOBS
  1. Describe the correct path an impulse takes across a synapse.
/ Axon of presynaptic neuron  SYNAPTIC CLEFT  dendrite of post synaptic neuron

  1. What are synaptic knobs filled with?
/ The synaptic knob has vesicles filled with a neurotransmitter that carries the signal.

  1. What are 5 types of glia cells?
/ Oligodendrocyte
Schwann Cell
Astrocyte
Microglia
Ependymal cells
  1. What is the function of glia cells?
/ They support the neurons
  1. Do glia cells carry nerve impulses?
/ No. The impulses jump over the oligodendrocytes and Schwann cells, and astrocytes and microglia are not involved in nerve impuses at all.
  1. Do glia cells process information in the nervous system?
/ No, the interneurons do that.
  1. What are the supporting cells of the nervous system?
  2. Where do most brain tumors originate from?
/ GLIA
Most tumors of the brain originate from glial cells.
  1. What is Wallerian Degeneration?
/ process that results when a nerve fiber is cut or crushed, in which the part of the axon separated from the neuron's cell body degenerates distal to the injury.
  1. What are the types of synapses?
/ axosomatic
neuroeffector synapses
axodendritic
axoaxonic
  1. Photo of two of the 4 types of glial cells
/ Oligodendrocytes
Schwann Cell

  1. Which cells provide the myelin sheath for neurons in the CNS?
/ OLIGODENDROCYTES
  1. Which cells provide the myelin sheath for neurons in the PNS?
/ SCHWANN CELLS
  1. What is the function of MYELIN SHEATHS
/ to speed up the rate of nerve impulse conduction.
  1. What are the BARE regions of axonal membranes found only in myelinated axons called?
/ NODES OF RANVIER
  1. What conducts impulses faster – myelinated or unmyelinated axon?
/ Myelinated
  1. Where are unmyelinated axons found?
/ Neuron cell bodies, dendrites, and unmyelinated axons in the PNS and CNS.
  1. Are unmyelinated axons thinner or thicker than myelinated?
/ Unmyelinated axons are thinner.
  1. What is myelin made of?
/ Mostly lipid
  1. What is an autoimmune disease where the oligodendrocytes (the myelin sheaths) are destroyed, interfering with the neuron functions in the CNS and brain?
/ MULTIPLE SCLEROSIS
  1. What is the most common neurological disease of young adults?
/ MULTIPLE SCLEROSIS
  1. What are the two differences between SCHWANN CELLS and OLIGODENDRICYTES?
/ Schwann cells are in PNS and each cell only forms one myelin sheath.
Oligodendricytes are in CNS and each cell can form more than one myelin sheaths.
  1. What are the 3 functions of an ASTROCYTE?
/
  1. Physically supports the neurons
  2. Transmits materials from capillaries to neurons
  3. Forms blood-brain barrier (BBB), which keeps out harmful substances and many medicines

  1. What is the only function of the blood-brain barrier BBB?
/ The only function of the blood-brain barrier is to help protect the central nervous system.
  1. DDefine MICROGLIA and their function
/ They are macrophages
They pick up bacteria and debris
41. What are ependymal cells? / Cells that line the ventricles of the brain and produce cerebral spinal fluid (CSF)
42. What is the portion of the CNS that is unmyelinated (cell bodies of neurons, glia, and dendrites)? / GREY MATTER
  1. What is the portion of the CNS with myelin
/ WHITE MATTER
  1. What is a collection of axons in the PNS?
/ NERVE; No cell bodies, dendrites, or synapses; just axons.
  1. What is a collection of axons in the CNS
/ TRACT
  1. Where is most information processed?
/ SYNAPSES in the CNS
  1. What is a collection of cell bodies in the PNS?
/ Ganglion
  1. What is a network of nerves called?
/ NERVE PLEXUS
  1. What are the neurons that leave the CNS to effect a muscle or gland?
/ MOTOR NEURONS
  1. What neurons go from body to CNS, carrying sensory information?
/ SENSORY NEURON
  1. What is a small neuron found only in the CNS?
/ INTERNEURON
  1. What is the function of interneuron?
/ it connects two other neurons in the spinal cord
  1. What makes the CNS complex?
/ The large number of interneurons in the CNS
  1. Where are the cell bodies of motor neurons and interneurons located?
/ In gray matter
  1. Gray matter in the CNS contains what structures?
/ Neuroglia, neuron cell bodies, dendrites. Everything except myelinated neurons
  1. For a substance to diffuse across a semipermiable membrane, what two conditions must be met?
/ a)The membrane must be permeable to the substance
b)The substance must have a concentration gradient
  1. At resting membrane potential, is the inside of the cell membrane positive or negative? What about the outside of the cell membrane?
/ Inside is negative, outside is positive
  1. What makes the inside of a cell membrane negatively charged?
/ Proteins inside the cell make it negative
  1. What changes the overall charge on the inside and outside of the cell membrane?
/ The charges change when sodium channels open during neuron stimulation
  1. When a cell is at resting membrane potential and is then stimulated by a neuron, what is the first thing that happens to start the change in the overall charge on the inside of the cell?
/ Sodium channels open and sodium enters the cell.
  1. Does potassium leave the cell because of neuron stimulation?
/ No, it can leave anytime because its channel is leaky.
  1. Why does sidedness exist (inside of cell negative, outside positive)?
/ a)The cell membrane has different permeabilities to each ion
b)Pumps exist which force particular ions into or out of the cell
c)Channels made out of protein selectively allow particular ions into or out of the cell.
  1. Why does potassium constantly want to leave a cell?
/ It wants to leave to diffuse down its concentration gradient
  1. Why does potassium want to get back into a cell?
/ It wants to get back into a cell because it is attracted to the negative charges on the protein inside the cell
  1. What is the resting membrane potential of a cell? Why does potassium constantly want to leave a cell?
/ The resting membrane potential is how negative or positive the charge of the cell membrane is when it is not being stimulated by a neuron. The resting membrane potential is Minus 70-minus 90 mV
  1. When does Depolarization occur?
/ Depolarization:
Enough sodium ions flow into the cell to make the membrane potential become positive
  1. When does Repolarization occur?
/ Repolarization:
Enough sodium ions flow out of the cell to make the membrane potential become negative
  1. What is an action potential?
/ Action Potential = depolarization + repolarization
  1. What is the correct sequence of events at a synapse?
/ The nerve impulse arrives at the synaptic knob of the presynaptic cell, then the neurotransmitter is released. The NT binds to receptors on the postsynaptic cell, generating an action potential in the postsynaptic cell axon. Then the NT is removed from the receptors of the postsynaptic cell, either by an enzyme, or they are taken back up into the presynaptic terminal knob and recycled.
  1. What are the three structural classifications of neurons?
/
  1. Unipolar
  2. Bipolar
  3. Multipolar

  1. What are the structural classification of neurons based on ?
/ the number of processes that project from the cell body.
  1. What happens if a neuron’s supply of neurotransmitters is exhausted?
/ It might be temporarily unable to transmit an impulse to another cell

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