Chapter 4 The Nervous System Flashcards
Neuron
So capable of transmitting electrical impulses and translating electrical impulse into chemical signals
Soma
- cell body
- Contains the endoplastic reticulum and ribosomes
Dendrites
Appendages coming out of the cell body that receive incoming messages from other cells
Axon hillock
Integrates information received from the dendrites that first travels to the cell body before reaching the axon hillock
* Plays an important role in the transmission of action potentials
axon
Long appendage That ends close to the target sector which can be an a muscle a grande or another neuron
Myelin sheath
Fatty membrane that insulates nerve fibers to prevent signal loss or crossing of signals
Nodes of Ranvier
Breaks in the Milan sheath along the axon critical for rapid signal conduction
Nerve terminal
Transmit signals to the next neuron this is where the new transmitters are released
Synaptic knob
Synaptic cleft
The space between neurons
Synapse
The nerve terminal, synaptic cleft, and postsynaptic membrane
Nerve
- Bundle of neurons in the peripheral nervous system
- Maybe sensory, motor, or mixed
tract
Accents are bundled and carry only one type of information unlike nerves
Multiple sclerosis
Immune response that leads to do myelination slows down the information transfer along a neuron
Glial cells
The other cells in the nervous system
Astrocytes
Nurse neurons and from the blood brain barrier
ependymal cells
Line the ventricles of the brain and Producer cerebrospinal fluid
Microglia
Phagocytic cells in the central nervous system
Cells that produce myelin around axons
Oligodendrocytes (CNS) and swans cells (PNS)
Sensory neuron
A.k.a. affarent neuron
* Transmit sensory information from Cincy receptive towards the spinal cord and brain
Motor neurons
A.k.a. affferent neurons
* Transmission and motor information from the brain and spinal cord to the muscles in grams
Interneurons
- Found between other neurons,
- the most neumerous
- Link to reflexive behavior
- Located predominantly in stone cordon bleu
Supraspinal circuits
Gray matter
Cell bodies and dendrites
White matter
axons
Spinal cord
Structure of the spinal cord
Sensory neurons bring information and enter through the back door so side of the spinal cord, modern neurons exit the spinal cord on the front ventral side.
*The cell body of the motor neuron is inside the spinal cord where received information the cell body of the sensory neuron is in the dorsal root ganglia which is outside the spinal cord
look up picture
neurons in the autonomic nervous system
- Preganglionic neuron has a soma in the Central nervousystem postganglionic neuron peripheral nervous system
Reflex arc
No input from the brain is required reflexes only require processing at the level of the spinal cord
Neural circuit
Monosynaptic reflex arc
There is one tonight between the sensory neuron in the motor neuron example knee-jerk reflex
Feedback loop
Polysynaptic reflex arc
- There is at least one interneuron between the sensory and motor neurons
- Example withdrawal reflex both quadricep muscles must be stimulated when stepping on a nail
Action potential
Resting membrane potential
-70 mV inside of the neuron is negative relative to the outside, potassium and sodium are used to maintain and generate the resting membrane potential
Leak channels
- Potassium channels allowed league of sodium potassium in route or out of the cell
- Potassium channels are more likely than sodium channels which means that the resting potential is closer to the equilibrium potential of potassium
Equilibrium potential potassium
-90 mV
Negative convention is because a positive ion is leaving the cell
Because of the brain potential of sodium
60mV
Positive because sodium is going into the cell
Na⁺/K⁺-ATPase
Sets up the gradient
Depolarization
Raising the membrane potential from interesting potential makes neurons more likely to fire and action potential
Hyper polarization
Lowering the membrane potential from its resting potential making the neuron less likely to fire in action potential
Threshold
-55mV - -40mV
If they ask on Hubaq receives enough excitatory input to be depolarized to threshold an action potential will be triggered
Summation
The additive effect of multiple signals which may be inhibitory or excitatory
Temporal summation
Multiple signals integrated in a short period of time
Spatial summation
review
Additive effects based on the number of signals and the location of the signals
Sodium channels
* Closed: before thrshold is reached
* Open: from thrshold to +35mV
* Inactive: +35 to reesting potential
Repolarization
Refractory periods
Absolute refractory period
Did refractory period
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