Exam 3

Which of the following statements helps to explain why a neurons resting membrane potential is measured as a negative voltage? Select all that apply.

-There are more potassium leakage channels on the plasma membrane of a nerve cell compared to the number of sodium leakage channels. -The plasma membrane is impermeable to protein anions, which contribute to the negative voltage.

If a medication blocked the binding of norepinephrine (NE) to beta 2 receptors, how would blood vessels respond as a result?

Blood vessels would constrict as a result.

If a particular medication enhanced the binding of norepinephrine to beta 1 receptors, how would the heart respond?

Heart rate would increase.

Use the following data to determine the problem that is present. pH = 7.51 PCO2 = 47 HCO3- = 28

Metabolic alkalosis

The speed or velocity at which an action potential moves (propagates) down an axon can vary depending on the structural characteristics of the neuron. Which structural features allow an action potential to be propagated at the quickest velocity?

Myelinated axons with the largest diameter

What structure helps to maintain the Na+ and K+ concentration gradients that contribute to a resting membrane potential?

Na+-K+ pump

Which statement describes repolarization, the second phase of the action potential?

Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.

Which of the following best demonstrates an example of cooperation of the parasympathetic and sympathetic nervous systems?

Parasympathetic stimulation causes vasodilation of blood vessels in the penis, leading to erection; sympathetic stimulation then causes ejaculation.

Which of the following will alter the pH of body fluids? Select all that apply.

Potassium chloride (KCl) Bicarbonate and

If an IPSP is occurring on a postsynaptic neuron what type of ion channels are opened?

Potassium ion channels

If a voltage gated sodium channel is closed and then it opens how would the movement of sodium ions across the plasma membrane of a cell change?

Sodium ions would flow into the cell along its electrochemical gradient.

Choose the correct statements below when considering the distribution of ions in the ICF and ECF.

-Sodium ions are in the greatest concentration in the ECF compared to the ICF. -Potassium ions are in the greatest concentration in the ICF compared to the ECF. -Protein anions are greatest in the ICF. -Calcium ions are in the greatest concentration in the ECF compared to the ICF.

If you drank 32 oz of water and then a half hour later you had the sense that you needed to urinate. What division of the peripheral nervous system would be activated allowing you to sense your full bladder?

visceral sensory fibers

If a nerve is generating an action potential, what type of ion channels would be open during the depolarization phase of the action potential?

voltage gated sodium and potassium channels

What happens to voltage-gated Na+ and K+ channels on an axon once the action potential voltage reaches a +30mV?

voltage-gated Na+‎ channels close, while voltage-gated K+‎ channels open.

Once a preganglionic axon reaches a trunk ganglion, one of three things can happen to the axon. Which of the following is NOT one of these three things?

The axon can course back into the spinal cord to synapse with preganglionic neurons in a different spinal segment.

Which of the choices below describes the "all or none phenonmenon" of an action potential?

The membrane potential must depolarize from the resting voltage of -70 mV to its peak value of +30 mV.

Which of the following choices explains the functional significance of a myelin sheath relative to the propagation of an action potential?

The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals.

What would happen to the rate of peristalsis in the small intestines if a drug bound to and blocked muscarinic receptors?

The rate of peristalsis would decrease.

Which statement below is false?

Voltage gated sodium channels begin to reset during the absolute refractory period of an action potential.

As you have studied various channels are present on the plasma membrane of an axon. Which of the following channels will be the first to open when a threshold stimulus is presented to a neuron?

Voltage-gated Na+ channels

Which of the following statements describes what will happen to voltage-gated channels on an axon's membrane once a stimulus reaches a threshold voltage?

Voltage-gated Na+ channels change shape, and their inactivation gates close.

Neurons can be classified based on their structure and function. Which standard is used to classify neurons into functional classes?

Whether or not the neuron has many processes extending from its cell body.

Which statement is false concerning a graded potential?

Which statement is false concerning a graded potential?

What is the position of the activation gate on a voltage gated sodium channel during the hyperpolarization phase of an action potential?

closed

What is the position of the inactivation gate on a voltage gated sodium channel during hyperpolarization?

closed

If Na+ channels on numerous dendrites open then the membrane potential changes relative to the neurons resting membrane potential. What type of signal will be generated on the dendrites when numerous Na+ channels open?

depolarization

If the frequency of action potentials moving down the sympathetic nerve fibers decreased then blood vessels would:

dilate

In general alpha and beta receptors are located on:

effector cells stimulated by postganglionic adrenergic fibers

The parasympathetic division is also called the "thoracolumbar division" of the autonomic nervous system.

false

Postsynaptic potentials are:

graded potentials that are occurring on postsynaptic neurons.

Which of the following accurately describes ganglia?

groups of cell bodies located outside the brain and spinal cord

Which portion of a phospholipid is polar?

hydrophilic head

If sympathetic nervous system activity was activated and parasympathetic nervous system activity was inhibited then heart rate would:

increase

Which of the following is not associated with activation of the sympathetic division of the autonomic nervous system?

increased digestive activity

Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel?

leakage channels

Which neuroglial cell is able to monitor the health of neurons and migrate toward injured neurons?

microglia

If a nerve is carrying impulses from the spinal cord to a skeletal muscle the neuron is most likely a:

motor neuron

Which of the following structures would serve as the efferent pathway in a homeostatic mechanism?

multipolar nerve

The two types of receptors that bind acetylcholine are __________ and __________ receptors.

nicotinic; muscarinic

Which glial cell will wrap around and insulate nerve fibers of the central nervous system?

oligodendrocytes

Which division of the nervous system has long preganglionic nerve fibers?

parasympathetic

Which division of the nervous system is responsible for controlling digestive activities?

parasympathetic division

Which of the following does not posses nicotinic receptors?

parasympathetic target cells

Which of the choices below will conduct an action potential at the slowest rate?

postganglionic fiber of sympathetic nervous system

The plasma membrane is not equally permeable to all substances. This difference in ion permeability helps to produce a resting membrane potential. When considering the ions below which has the greatest permeability across a nerve cell's plasma membrane?

potassium ions

Which nerve fibers are cholinergic?

preganglionic fibers of sympathetic nervous system preganglionic fiber of parasympathetic nervous system somatic nerve fiber postganglionic fiber of parasympathetic nervous system

What part of the motor (efferent) division does not always posses a synaptic cleft?

sympathetic nervous system

Which autonomic neurons release norepinephrine as a neurotransmitter?

sympathetic postganglionic nuerons

What part of a neuron integrates all the incoming signals that are recieved?

cell body

Where in the neuron are neurotransmitters manufactured?

cell body

Which statement would be accurate concerning carrier mediated facilitated diffusion? Select all that apply.

-Carrier mediated facilitated diffusion allows glucose to cross the plasma membrane -Carrier mediated facilitated diffusion is passive.

Which type of signal propagation occurs in unmyelinated axons?

Continuous conduction

Which statement is accurate concerning a neuron?

Dendrites are branched and they generate graded potentials.

The two divisions of the autonomic nervous system (ANS) normally have a(n) __________ relationship.

antagonistic

Glial cells are abundant in the nervous system, which glial cell would play a role in the exchange of glucose between the blood and a neuron?

astrocyte

Which neuroglial (glial) cell of the nervous system plays a role in exchanges that occur between a neuron and capillary?

astrocytes

Observe the neuron structure of the somatic and autonomic nervous systems. Which system conducts action potentials at a slower rate?

autonomic efferent chain

You recently learned about skeletal muscle physiology and the events that occur prompting a skeletal muscle to contract. Where in this study have you seen voltage gated ion channels?

axon terminal sarcolemma of muscle cell

Which of the following is classified as an inorganic compound? Select all that apply.

bases salts acids

If a neuron's voltage is moving from resting membrane potential (RMP) to hyperpolarization the inside of the neuron's plasma membrane is:

becoming more negative.

The autonomic nervous system would send impulses to all of the following except:

biceps muscle

Which organ does not receive significant innervation from both divisions of the autonomic nervous system?

blood vessels

Which of the following events would occur if the sympathetic nervous system was activated?

blood vessels would dilate

What is the nature of the compensation for the problem that is present. pH = 7.51 PCO2 = 47 HCO3- = 28

breathing rate decreases

When an action potential moves (propagates) along the entire length of an axon it does so because:

repolarizing currents established by the efflux of K+‎ trigger an action potential at the next segment of the axon

Which transport mechanism will transport an amino acid and sodium into a body cell?

secondary active transport

Which of the following is innervated by the autonomic nervous system?

smooth muscle cardiac muscle glands

If a nerve's voltage is demonstrating a resting membrane potential, which type of ion channel must be open allowing for the flow of ions?

sodium and potassium leakage channels

An athlete engages in an intense game of tennis, what division of the nervous system will command the heart to beat at a faster rate?

the sympathetic division of the autonomic nervous system

A synapse is a junction that can occur between:

two nerve cells. a nerve cell and glandular cells. a nerve cell and skeletal muscle cell.

If a nerve fiber is carrying information from a body receptor toward the spinal cord and brain, then the structure of the nerve fiber is most likely:

unipolar