- What responses are generated by the nervous system when you run on a treadmill? Include an example of each type of tissue that is under nervous system control.
Running on a treadmill involves contraction of the skeletal muscles in the legs, increase in contraction of the cardiac muscle of the heart, and the production and secretion of sweat in the skin to stay cool.
2. When eating food, what anatomical and functional divisions of the nervous system are involved in the perceptual experience?
The sensation of taste associated with eating is sensed by nerves in the periphery that are involved in sensory and somatic functions.
3. Multiple sclerosis is a demyelinating disease affecting the central nervous system. What type of cell would be the most likely target of this disease? Why?
The disease would target oligodendrocytes. In the CNS, oligodendrocytes provide the myelin for axons.
4.Which type of neuron, based on its shape, is best suited for relaying information directly from one neuron to another? Explain why.
Bipolar cells, because they have one dendrite that receives input and one axon that provides output, would be a direct relay between two other cells
5.Sensory fibers, or pathways, are referred to as "afferent." Motor fibers, or pathways, are referred to as "efferent." What can you infer about the meaning of these two terms (afferent and efferent) in a structural or anatomical context?
Afferent means "toward," as in sensory information traveling from the periphery into the CNS. Efferent means "away from," as in motor commands that travel from the brain down the spinal cord and out into the periphery.
6.If a person has a motor disorder and cannot move their arm voluntarily, but their muscles have tone, which motor neuron—upper or lower—is probably affected? Explain why.
The upper motor neuron would be affected because it is carrying the command from the brain down.
7.What does it mean for an action potential to be an "all or none" event?
The cell membrane must reach threshold before voltage-gated Na + channels open. If threshold is not reached, those channels do not open, and the depolarizing phase of the action potential does not occur, the cell membrane will just go back to its resting state.
8.The conscious perception of pain is often delayed because of the time it takes for the sensations to reach the cerebral cortex. Why would this be the case based on propagation of the axon potential?
Axons of pain sensing sensory neurons are thin and unmyelinated so that it takes longer for that sensation to reach the brain than other sensations.
9.If a postsynaptic cell has synapses from five different cells, and three cause EPSPs and two of them cause IPSPs, give an example of a series of depolarizations and hyperpolarizations that would result in the neuron reaching threshold.
EPSP1 = +5 mV, EPSP2 = +7 mV, EPSP 3 = +10 mV, IPSP1 = -4 mV, IPSP2 = -3 mV. 5 + 7 + 10 - 4 - 3 = +15 mV.
10.Why is the receptor the important element determining the effect a neurotransmitter has on a target cell?
Different neurotransmitters have different receptors. Thus, the type of receptor in the postsynaptic cell is what determines which ion channels open. Acetylcholine binding to the nicotinic receptor causes cations to cross the membrane. GABA binding to its receptor causes the anion chloride to cross the membrane.
No comments:
Post a Comment