Flashcards in Nervous System** Deck (77):
What are the 3 functions of the nervous system?
Major controlling, regulatory, and communication, keeps us in touch with the internal and external environment, responsible for maintaining and regulating homeostasis
What are the 2 parts of the nervous system?
CNS and PNS
All nerves of the body residing outside of the brain and spinal cord
Consists of brain and spinal cord
Smooth muscle, cardiac muscles, glands
Contains the nucleus and most of the cytoplasm
Projections that bring impulses into the neuron
Long projection that carries impulses away form the neuron
Insulating layer produced by Schwann cells
Sheath formed form Schwann cells on the exterior of some axon
Gaps between Schwann cells
Nodes of Ranvier
Junction between 2 communicating neurons
Has many processes and part of brain or spinal cord
2 processes; eyes nose, ears
1 process; outside the brain and spinal cord
Carry impulses from the body part into the brain or spinal cord
Most common type of neuron that communicates from one neuron to the other; relays information
Carry nerve impulses out of brain or spinal cord to effectors (glands or muscles)
Support neurons and phagocytize bacterial cells and cellular debris, part of the immune system
Where are microglial cells found?
Provide insulating layers of myelin around axons within brain and spinal co
Structural support, join parts by their abundant cellular processes, help regulate concentrations of nutrients and ions within tissue
Where are oligodendrocytes found?
Align along nerve fibers
Where are astrocytes found?
between neurons and blood vessels
Specialized epithelial cells in the CNS that produce CSF
Where are ependymal cells found?
brain and spinal cord
Forms a myelin sheath around axons
Where are Schwann cells found?
Brings impulse to synapse
Receiving neuron at synapse
Chemical in a synaptic cleft which relays information across the gap
The action of the neurotransmitter on a postynaptic cell is either _______ or _____.
Excitatory or inhibatory
Turning a process on
Turning a process off
Areas of high concentration or low concentration
There is an uneven arrangement of ions inside and outside the membrane of the neuron
Cell membrane potential
Why does a cell membrane potential occur?
There are ion pumps that for K+ into the cell and Na+ outside of the cell. There are also ion gates
In a resting neuron, all Na+ gates are ____(open or closed)
What is the result when the Na+ gates are closed?
There are more positive ions on the outside of the cell
What happens when there is a stimulus applied to a dendrite?
Na+ channels open
As the generator potential builds in the dendrite, what do the ions begin to do?
spread to the cell body and then to the initial segment of the axon
Chemicals that cross the synapse
What do the neurotransmitters do?
Bond to receptor sites on the dendrite of the next neuron
How does the myelin sheath help?
Speeds up the process
Bring sensory information towards CNS
Carry impulses form CNS to effectors
The routes that nerve impulses follow as they travel through the nervous system
Simplest of the nerve pathways
Automatic Responses to a change in the environment
What do reflexes help with?
Maintain homeostasis by controlling involuntary processes like heart rate, breathing rate, etc.
What do monosynaptic reflexes include?
2 neurons and 1 synapse
Reflex contraction of a muscle when an attached tendon is pulled
Reflexes associating with maintaining normal body posture
Involves one or more integrated neurons in the reflex arc pathway
How long do neurons last?
Cluster of cell bodies in the CNS/PNS
Bundle of nerve fibers running through the CNS
Bundle of nerve fibers running through the PNS
What's the difference between white and gray matter?
Gray is unmyelinated while white is
Gradient of electrochemical potential for an ion that can move across a membrane
The difference in electrical charge between the inside and outside of an undisturbed nerve cell membrane
Resting membrane potential
Loss of an electric charge
Change in cell membrane making it more negative
Second phase of the action potential
What is the state of sodium channels during the resting state, depolarization, repolarization, and after hyperpolarization?
Close, close, open, close
What is the state of channels during the resting state, depolarization, repolarization, and after hyperpolarization?
Close, open, close, close
How is an action potential propagated?
Na+ ions travel down the axon; resting potential, depolarization, repolarization, hyperpolarization
The neurons responds completely not partway through
All or nothing response
What variables influence the conduction velocity of a neuron?
If it is myelinated or not, thickness of axon
Is there an accumulation of positive or negative charges in a resting neuron?
A drug that blocks the opening of sodium channels
What are 2 important factors that drive the movement of Na+ and K+ across the membranes?
Electrochemical and concentration gradient
How many Na+ ions get out of the cell?