Question

4. Draw a synapse between 2 neurons. Label the following: Presynaptic neuron, Postsynaptic neuron, Synaptic vesicles, Voltage-regulated calcium channel, Chemical-regulated sodium channel. 5. Draw a diagram of the preganglionic neuron, postganglionic neuron, and effector for both Sympathetic Nervous System and Parasympathetic Nervous System. indicate which neurotransmitter is released by each neuron and label the receptors at all locations for the neurotransmitter. 6. Which cells have a resting membrane potential? Which cells can have an action potential? 7. Circle which of the following choices pertain to a Graded Potential. (1) Localized or Widespread (2) Gradations or All-or-None (3) Threshold or Not (4) Short distance or Long distance

Answer 1

4. Synapses

communication between individual neurons is performed at a morphologically and functionally highly specialized region named the synapse . The name synapse was coined from the Greek syn, meaning “together”, and haptein, meaning “to clasp”. The synapse is structurally shaped by the presynaptic and the postsynaptic membrane both separated by the synaptic cleft.

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5. Post and pre ganglionic neuron

Neurotransmitter Neurotransmitter transporter Synaptic vesicle Axon terminal Voltage- gated Cat channel Receptor Postsynaptic density Synaptic cleft >Dendrite

The preganglionic neuron leaves through the ventral root. After the ventral and dorsal roots fuse to form thespinal nerve the preganglionic neuron goes to sympathetic ganglia that are connected to one another and run parallel to the spinal column on either side. The chain of ganglia is the sympathetic chain or sympathetic trunk.

Because the axons of the preganglionic neurons may branch and travel up and down the sympathetic chain, a singlepreganglionic neuron can synapse with many postganglionic neurons up and down the sympathetic chain. Hence, the effects of stimulation are widespread.

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CNS PNS Preganglionic neuron Postganglionic neuron Effector organs: Cardiac muscle Smooth muscle Glands Adipose tissue Autonomic ganglion © 2011 Pearson Education, Inc.

Neurotransmitter acetylcholine

6.

The resting membrane potential is a result ofdifferent concentrations inside and outside the cell. The difference in the number of positively charged potassium ions (K+) inside and outside the cell dominates the resting membrane potential .

An action potential is a rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane with a characteristic pattern. Sufficient current is required to initiate a voltage response in a cell membrane; if the current is insufficient to depolarize the membrane to the threshold level, an action potential will not fire.

Examples of cells that signal via action potentials are neurons and muscle cells.

7.

Localized, short distance, threshold, gradation

Graded potentials are initiated by a stimulus that vary in magnitude depending on the strength of the stimulus. ... Graded potentialsdissipate with distance from stimulus. On the other hand, action potentials occur whengraded potentials reach the axon hillock at a certain level of depolarisation (around -55mV).