BIO 203 Lecture Notes - Lecture 5: Somatic Nervous System, Skeletal Muscle, Anterior Grey Column

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goldjackal516

22 Mar 2017

School

Stony Brook University

Department

Biology

Course

BIO 203

Professor

William Collins, Sarah Malmquist

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Document Summary

Evaluate class 5: a somatic motor neuron forms a synapse with a skeletal muscle cell. You apply a voltage-gated calcium channel antagonist to the synapse, and it affects both cells in the synapse. This blocks the skeletal muscle cell from contracting. Demonstrate your knowledge of both synaptic transmission and cell signaling within the skeletal muscle in your answer. Somatic motor neurons are the only neurons that innervate skeletal muscle. Calcium (ca2+) is a very important second-messenger molecule that can do a variety of processes including opening voltage-gated channels. Ach is prevented from binding to its receptor (nachr). Therefore, skeletal muscles will not contract: a patient has a tumor that is secreting excess acth. You measure the levels of cortisol and crh in her plasma. Explain each value using your understanding of endocrine principles. The stress pathway for the release of cortisol, a steroid hormone, contains a short-loop negative feedback mechanism in which acth is feeding back on.

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A somatic motor neuron forms a synapse with a skeletal muscle cell. You apply a voltage-gated calcium channel antagonist to the synapse, and it affects both cells in the synapse. This blocks the skeletal muscle cell from contracting. Explain why this occurs. Demonstrate your knowledge of both synaptic transmission and cell signaling within the skeletal muscle in your answer.

The junction specialized for the transmission between a neuron and another cell is called a (1) _____ ______. Usually, the signal being sent to the receiving cell is carried by chemical messengers called (2) _____. (3) _____ is an example of this type of chemical messenger, which diffuses across the synaptic cleft, combines with protein receptor molecules on the muscle cell membrane, and soon thereafter is rapidly broken down by enzymes. At an (4) ____ synapse, the membrane potential is driven toward the threshold value and increases the likelihood that depolarization and an action potential will occur. At an (5) ____ synapse, the membrane potential is driven away form the threshold value, and the receiving neuron becomes hyperpolarized and is less likely to achieve an action potential. A specific transmitter substance can have either excitatory or inhibitory effects depending on which type of protein channel it opens up in the (6) ____ membrane. (7) ____ are neuromodulators that inhibit perceptions of pain and may have roles in memory and learning, emotional states, temperature regulation, and sexual behavior. (8) ____ ________ at the cellular level is the moment-by-moment tallying of all excitatory and inhibitory signals acting on a neuron. Incoming information is (9) ____ by the cell bodies, and the charge differences across the membranes are either enhanced or inhibited. Some narrow-diameter neurons are wrapped in lipid-rich (10) _______ produced by specialized neuroglial called Schwann cells; each of these is separated from the next by a(n) (11) ________ ________ - a small gap where the axon is exposed to extracellular fluid. A (12) ____ is an involuntary sequence of events elicited by a stimulus. During a (13) _______ ________, a muscle contracts involuntary whenever conditions cause a stretch in length; many of these help you maintain an upright posture despite small shifts in balance. Imbalances can occur at chemical synapses; a neurotoxin produced by Clostridium tetani blocks the release of GABA and glycine, thus freeing the motor neurons from (14) _____ control, which may cause tetanus â a prolonged, spastic paralysis that can lead to death. A. Excitatory H. Stretch reflex B. Inhibitory I. Summed C. Myelin J. Neurotransmitters D. Chemical synapse K. Postsynaptic E. Synaptic integration L. Endorphins F. Exposed node M. Acetylcholine (ACh)

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a) Which of the following statements about the autonomic nervous system is INCORRECT?

A The preganglionic fibres in the parasympathetic division are usually long compared to the postganglionic fibres

B The sympathetic division mediates responses that allow the body to respond to âflight and frightâ situations

C The ganglia of the sympathetic division are usually close to the spinal cord

b) Glutamate is an example of an excitatory amino acid neurotransmitter that acts via direct synaptic transmission when it is released from presynaptic neurons in the brain

Based on the background information, which of the following is a CORRECT statement regarding events at the synaptic cleft after glutamate is released?

A Glutamate acts by stimulation of receptors on the presynaptic neuron

B The postsynaptic glutamate receptors are in the family of tyrosine-kinase linked receptors

C On the postsynaptic membrane, glutamate activates ligand-gated sodium channels, which are an example of ion-channel linked receptors

D The events at this synapse are an example of electrical transmission

E The pathway of receptor activation includes activation of a signal transduction pathway and production of second messengers

D The adrenal medulla is a sympathetic ganglion

E The parasympathetic nerves arise from the brain stem and the sacral region of the spinal cord

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BIO 203 Lecture Notes - Lecture 5: Somatic Nervous System, Skeletal Muscle, Anterior Grey Column

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