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Apologia Health Mod 7
The study guide from Apologia Health Mod 7. My personally study cards.
Terms in this set (35)
Bundles of axons and their sheaths which extend from the CNS.
Collections of neuron cell bodies, which are outside of the CNS.
Nerves which originate from the spinal cord.
Nerves which originate from the brain.
Neurons which transmit action potentials from the sensory organs to the CNS.
Neurons which transmit action potentials from the CNS to the effector organs.
Somatic Motor Nervous System
The system that transmits action potentials from the CNS to the skeletal muscles.
Automatic Nervous System
The system that transmits action potentials from the CNS to the smooth muscles, cardiac muscles and glands.
Division of the ANS that generally prepares the body for physical activity
Division of the ANS that regulates resting and nutrition-related functions such as digestion, defecation, and urination
A neuron that conducts action potentials from one neuron to another within the CNS.
The ability to create an action potential in response to a stimulus.
A measure of the charge difference across the cell membrane.
Your eyes send information to your brain that form an image of the words you read. Is this information being sent along afferent or efferent nerves?
Afferent nerves, since those are nerves that carry information from your sensory organs (eyes) to the CNS (your brain)
When you are digesting food, smooth muscles churn your stomach. Is this being controlled by the afferent or efferent division of the PNS? What is the most specific way to describe the nerves in this situation?
Efferent division. The most specific you can be is that the parasympathetic division of the automatic nervous system is being used.
Name six types of neuroglia and their functions.
Oligodendrocytes: bind CNS neurons together and insulate the axons.
Schwann cells: insulate PNS axons.
Microglia: engage in phagocytosis to fight infections.
Astrocytes: form the blood-brain barrier.
Non-ciliated ependyml cells: secrete cerebrospinal fluid.
Ciliated ependymal cells: move cerebrospinal fluid around so that it stays homogeneous.
What are the differences between a sensory nerve, a motor nerve, and a mixed nerve? What is the most common nerve in the body?
Sensory nerve carries only sensory information from a receptor to the CNS.
Motor nerve carries signals only from the CNS to effector organs like muscles.
Mixed nerve carries both. Most nerves in the body are mixed.
An axon is covered by an oligodendrocyte. Is it a part of the CNS or PNS? Will it regenerate a new axon if severed?
Oligodendrocytes are found only in the CNS. The axon will not regenerate as it must have Schwann cells for that.
An axon is covered by several Schwann cells. If it is severed, will it definitely heal? Why or why not?
Not necessarily. Not only does it need Schwann cell but must also be lined up well for the Schwann cell to guide the axon to it.
At one point in the axon, there is a high concentration of potassium ions outside of the cell and a high concentraion of sodium ions inside the cell. Is the neuron at rest?
It is not at rest.
At one point in the axon, there is a high concentration of sodium ions outside of the cell and a high concentration of potassium ions inside the cell. Is the neuron at rest?
You cannot tell.
A stimulus creates a change in the potential difference between the inside and outside of the cell, but no action potential is created. What is this called?
A subthreshold stimulus.
The following steps occur in creating an action potential. Put them in order:
A. Sodium gates open, and sodium ions rush into the cell according to the dictates of diffusion.
B. Sodium and potassium gates are closed. Sodium-Potassium exchange pump brings the system back to it's original state.
C. Sodium and potassium gates are closed. Sodium ions are concentrated outside the cell, potassium ions are concentrated inside the cell.
D. Sodium gates close and potassium gates open. Potassium rushes out of the cell according to the dictates of diffusion.
The proper order is:
C. A. D. B.
There are specific names given to step (a) and step (d). What are they?
A. Is depolarization.
D. Is reparkzation.
What keeps an action potential on an axon from stimulating another action potential which will travel back toasted the cell body?
The absolute refractory period.
Why do myelinated axons carry action potentials faster than unmyelinated axons?
Because myelinated axons allow saltatory transmission.
When you cut yourself, you feel an instant, sharp pain followed later by a dull ache. Why do you fermented two different pains, and shy do they come in that order?
The difference in pain and timing is due to the signal traveling on myelinated or unmyelinated axons.
If you press your finger lightly against an object, you feel a certain amount of pressure. Pressing harder against that same object causes you to feel more pressure. What is the difference between the action potentials in these two situations?
The difference is the frequency of the action potentials.
A signal needs to travel a long long way in the body. It needs to have exactly the same properties at IRS destination as it did when it started. Should this signal be sent along a very long axon or a few shorter axons which are connected by synapses?
A long axon should be used.
The potential difference in a postsynaptic neuron changes from -85 mV to -95 mV at the point of a synapse. What has happened? What can you stay about the relative amounts of potassium and sodium ions outside f the membrane?
An inhibitory postsynaptic potential has occurred. The potassium ion concentration will be higher than for the resting state outside of the membrane. The sodium ion concentration will be unchanged.
Twelve action potentials are traveling down an axon in a very short time period. They reach a synapse, and the ppstsynaptic neuron sends only two action potentials down it's axon. Is this an excitatory synapse or a inhibitory synapse?
An excitatory synapse.
We discussed three kinds of "circuits" which can be formed by neurons. Name the three circuits and what they are used for.
Converging circuit: many inputs are digested down to just one limited output.
Diverging circuit: one input creates many outputs.
Oscillating circuit: prolongs the effect of a stimulus.
Figure on problem 4.
Identify the terms A.- L.
A. Presynaptic terminals
B. Node of Ranvier
C. Collateral axon
D. Golgi apparatuses
I. Cell body
J. Axon hillock
L. Myelin sheath
Figure on problem 6.
Identify the terms A.- E.
Figure on problem 19.
Identify the terms A.- F.
A. Calcium channels
B. Synaptic vesicle
C. Sodium channels
D. Presynaptic terminal
E. Synaptic cleft
F. Postsynaptic membrane