The neuron Flashcards
What are the name of the three systems in the body and what do they use to communicate?
1) nervous system is for fast rapid communication. they use neurons for short communication
2) the paracrine system use local mediators for communication in immediate surroundings
3) the endocrine system use hormones to communicate short distances
What are the parts of the nervous system?
1) brain
2) spinsl cord
3) nerves snd neurons
4) sensory organs(eyes,ears, etc)
what is the function of the neuron? what are the parts of the neuron?
The function is to communicate with the neighboring cell via electrical are chemical signals.
1) dendrite -receives signal to be transmitted
2) axon hillock
3) axon
4) nissl
5) synapses
6) cell body(contains organelles)
7) glial cell
8) node of ranvier
9) myelin sheath
10) axon terminal
What is the flow of a signal in a neuron?
the dendrite receive the signal. the cytosol then has a disturbance in its electrical field . The signal then travels to the axon hillock which create a action potential in all directions including down th axon. Then the signal travels to the end terminals. Then to the synapes across the synaptic cleft and to the next neuron.
what is a synapse?
the area between the neuron and the successive cell. they allow the neuron to pass a electrical or chemical signal.
what is a motor end plate?
a synase between a neuron and a muscle.
what is the nerve filament that synapse with the next cell?
presynaptic terminals, synaptic knobs or synaptic buttons.
what is the presynaptic cleft?
The space between the dendrite of one neuron and the axon of another.
What is the function of calcium in the neuron?
The neurotransmitters is house in vesocles in the presynaptic terminal. when the Ca+ concentration rises neurotransmitters diffuse across the presynaptic cleft. they either excite or inhibit the next terminal. they are called excitatory or inhibitory transmitters.
Explain the resting potential of a cell.
the resting potentilal maintains a electrical potential of 90mV. The positive is on the outside and the negative(-90mV) is on the inside of the membrane.
how is the resting potential of the neuron is maintained?
Since the outside of the cell is more positive it pumps 3Na+ out the cell and 2K+ in the cell. This done by a ATPase pump. the cell also has potassium leak channels that allow potassium to leak to the outside of the cell membrane to maintain a positive potential on the outside.
Explain the action potential.
when there is a disturbance in the electric field of the membrane voltage gated Na+ channels bein to open and allow Na+ to flow into the cell. When one channel opens it causes a chain reaction and the rest of the chasnnels begin to open. This cause depolyrization of the membrane. when the voltage is flipped with the mor positive on the inside and the negative on the outside.
after all the Na+ channels have closed voltage gated potassium channels open and K+ flows out of the cell. the resting potential is returned. this is called repolarization.
Because K+ channels are so slow the inside of the cell become more negative than the resting potential. This is called hyperpolarization.
the action potential is a all or nothing event. it doesnt matter the size of the stimulus the action potential is generated if the membrane is completely depolarized. if the treshold stimulus is reach then it will occur.
What is a glial cell? what is a specialized glial cell for the peripheral nervous system?
a glial cell provides support for the neuron by wrapping the axon of the neuron in myelin sheaths.
Schwann cells are specialized glial cells for neurons of the peripherial nervous system. They insulate the cell by wrapping it in a myelin sheath.
whta is the soma?
It is the body of a neuron cell.
What are some exitatory/inhibitory transmitters?
acetylcholine - excites other neurons
GABA- inhibits other neuron
