Nervous System Flashcards
What part of the neuron receives an impulse from another neuron through a synapse reaction?
Dendrites
What makes the cell body?
Nucleus, cytoplasm, and cell membrane
What wraps the axon in order to make them transmitt electrical signals faster?
Myelin sheath
What is the part on the very end of the neuron called?
Nerve endings
What is a synaptic cleft?
The gap between a nerve ending that is stuck on to a dendrite on another neuron
How does the chemical transmission of neurotransmitter works?
When the body receives a stimulus, it sends electrical signals down the axon terminal, generating positive sodium ions to diffuse into the cell.
These sodium ions trigger the synaptic vesicles inside the axon terminal to bind to the receptors on the dendrites of another neuron. The vesicles dispurse to the postsynaptic neuron, specifically on the receptor region of the dendrite, releasing the many neurotransmitter cells inside it around the cell.
(optional) When the neurotransmitter has finished sending their signals, they can undergo a process called a reuptake, where the neurotransmitter gets diffused back up or digested by an enzyme to make them dissapear.
How many mV is needed to open an ion channels to open?
- 55 mV, if less it wouldn’t open at all.
How does the cell balance the gradient during action potential/electrical transmission?
Describe with the terms ‘polarization’ and ‘depolarization’.
When the body receives a stimulus that reaches -55 mV, it opens up the ion channels and diffuse positive sodium ions to the inner part of the cell, causing the cell to be polarized until it turns to a positive charged cell.
To balance this out, another ion channel opens up beside it to release negatively charges potassium ions to the external part of the cell, diffusing. This action is called polarizing, however it could be hyperpolarized at first since the ion channels are still opened and the potassium ions keep on diffusing out of the cell.
To eventually come back being polarized, they have to wait until the ion channels are closed and the gradient becomes balanced again.
What causes the gradient to become imbalanced?
The sodium-potassium pump. This is a reaction that describes when 2 sodium ions are pumped inside of the cell, 3 potassium ions are diffused outside of the cell. This creates an unbalanced gradient between the external and internal part of the cell.
How does a reflex arc travel?
When a receptor cell receives a stimulus, the sensory neuron sends an electrical signal to the central nervous system (spinal cord), where they process the signal using their interneurons which contains an amount of synapses.
After the synapse is done, the electrical signal travels along the axon using the motor neuron to the effectors, that could be muscles or tissue, and they will act accordingly.
What does an autonomic reflex do?
It effects cardiac, smooth muscles, and glands. It can both inhibit or stimulate the smooth muscle glands.
(e.g.)
1. It contracts both pupils when a bright light is shone on them.
2. Focus on a close-distanced object constricts them.
What does a somatic reflex do?
It effects the skeletal muscles that inclides withdrawal, strech, and tendon reflexes.
(e.g.)
1. Cornial blinking which indicates to be a respond to a stimulus.
2. Knee jerking.
