Nervous System Flashcards
Name the different parts of the nervous system.
CNS- Brain & Spinal cord
PNS- Nerves
Describe gray matter in the CNS: where is it located? why is it gray?
Gray matter is a region that contains many cell bodies. It is located in the cerebral cortex which is the entire outer portion of the brain with a wrinkled appearance, and also makes up a gray “H” In the middle of the spinal cord. It is gray from cells piled on top of each other.
Describe white matter in the CNS: where is it located? why is it white?
White matter is a region that contains many axons. It is white from being electrically insulated by a lipid-rich substance called myelin. It is located inside of the brain revealed by a cut, and also in the spinal cord where in both it is called the “tracts”
What does “afferent” mean?
afferent can relate to “arrives”
Name the two types of afferent information in the nervous system, and give examples of each
Stuff you know- somatic branch. This includes your senses, and the movement of your skeletal muscle, joints, and tendons. Some examples are: Touch, Taste, Temperature, Balance.
Stuff you dont know- Visceral branch. Heart rate, blood pressure, chemical composition of the body
What does “efferent” mean?
efferent related to “exit” and “effectors”
Name all the types of efferent information in the nervous system.
Things we are aware of- Somatic branch. You decide to move your skeleton. Your body decides to itself like reflexes. Patellar reflex and hiccuping.
Things we do not consciously control- Autonomic branch. ANS commands are usually tweaking your body’s internal environment to maintain homeostasis, and affect your cardiac muscle, smooth muscle, and glands. Heart rate, respiratory rate, pupil size, sexual function.
List the anatomical structures of a neuron and explain the function of each.
Soma- The body. Contains nucleus and organelles
Axon- Neurons have only one axon. The axon extends out of the soma and is what propagates the nerve impulse.
Dendrites- Receives information from other neurons at specialized areas of contact called synapses.
List the three functional types of neurons and explain the function of each.
Sensory neurons- Responsible for sensation such as the pain from a needle piercing the skin.
Interneurons- Responsible for integration, meaning that stimuli are analyzed and perhaps compared with other information before a decision is made about the response. For example, if you intentionally pierced your skin with the needle to get a tattoo, you probably wouldn’t jerk your skin away (at least, I hope not). On the other hand, if you unintentionally stepped on a needle, the interneurons would probably know what response to initiate right away.
Motor neurons- Responsible for the response. In this case of a stepping on a needle, motor neurons would tell the effectors (in this case, skeletal muscle) in one leg to lift up, while also telling effectors in other parts of the body to shift weight to the un-needled leg.
What is a glial cell?
Also known as neuroglia. They are the supporting cells found in the CNS and PNS
Can you name three types of glial cell and explain their functions?
Astrocytes- Maintains the ideal living conditions for the neurons by letting good things get near while keeping bad things away
Schwann cells- Myelin axons in the PNS
Ependymal calls- Converts blood into cerebrospinal fluid (CSF) Basically they allow only the best parts of blood to trickle out.
Discuss myelin: what is it made of? what cells make it? what is its function, and what happens if nerve axons are demyelinated?
Myelin is a lipid-rich substance that surrounds the axon of neurons and by doing so creates a “myelin sheath” that allows electrical impulses to transmit more quickly and efficiently along the nerve.
Multiple sclerosis (MS) is one such diseases. As the insulation around the axons is destroyed by the disease, scarring occurs in the CNS.
Summarize the steps that take place when action potentials are generated.
Action potentials traveling down neurons… neurotransmitters being released at synapses… a voltage change that reaches a threshhold and triggers another action potential… and eventually a movement of your muscles to initiate a response. And all of this occurs in a fraction of a second!
Explain the difference between saltatory conduction and continuous conduction.
When action potentials propagate along an unmyelinated axon, it is called continuous conduction. In a myelinated axon, it is called saltatory conduction. Continuous conduction is slow because of all the opening and closing of channels; saltatory conduction is faster because the action potential basically jumps from one node to the next
Explain what takes place at a chemical synapse.
When a chemical signal (neurotransmitter) is released from the neuron and it affects the next neuron.
