BMS 290 EXAM 3 Online Homework

Place these structures in the correct order for an autonomic reflex: 1) Postganglionic autonomic neuron 2) Target cell 3) Receptor 4) CNS integrating center 5) Preganglionic autonomic neuron 6) Sensory neuron

3, 6, 4, 5, 1, 2

Which of the following would reflect the typical net hydrostatic pressure (HP) at the arterial end of the capillary?

34 mm Hg

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?

AV node

Increased pressure in the ventricles would close what valve(s)?

AV valves only

Neurons in the parasympathetic pathway use which of the following neurotransmitters?

Acetylcholine

Postganglionic neuron from the parasympathetic nervous system.

Acetylcholine

Preganglionic neuron from the parasympathetic nervous system.

Acetylcholine

Preganglionic neuron from the sympathetic nervous system.

Acetylcholine

Somatic motor neuron.

Acetylcholine

What are Norepinephrine receptors?

Alpha-1 Beta-1 Beta-3

Which about autonomic reflexes is FALSE? a. Many autonomic reflexes are characterized by tonic activity, a continuous stream of action potentials. b. Autonomic reflexes are all monosynaptic, with their synapse in the central nervous system. c. Vomiting, sneezing, and coughing are all examples of autonomic reflexes. d. Integrating centers for autonomic reflexes in the brain include the hypothalamus, brain stem, and limbic system.

Autonomic reflexes are all monosynaptic, with their synapse in the central nervous system.

What are Epinephrine receptors?

Beta-1 Beta-2

As blood flows away from the heart, how does overall blood pressure in vessels change? Why?

Blood pressure decreases, because of the effects of friction between the vessel walls and the moving blood.

In a cardiac autorhythmic cell, which ion is responsible for the increase in membrane potential from threshold during an action potential?

Ca2+

In the condition known as complete heart block, what happens?

Electrical signals from the SA node never reach the ventricles, so the contraction of the atria is not coordinated with the contraction of the ventricles.

Which is the correct relationship among pressure, flow, and resistance?

Flow is directly proportional to change in pressure and inversely proportional to resistance.

Epinephrine and norepinephrine increase ion flow through ________ channels.

If and Ca2+

What causes active hyperemia?

Increased metabolism results in a local increase in CO2.

Which statements apply to the parasympathetic division of the nervous system?

It is dominant during "resting and digesting" and its ganglia on or near their target organs.

Which is NOT a correct comparison of cardiac myocytes to other muscle cell types? a. Like smooth muscle cells, cardiac muscle is under hormonal control. b. Like skeletal muscle cells, actin and myosin are organized into sarcomeres. c. Like some smooth muscle cells, cardiac myocytes are electrically coupled. d. Like skeletal muscle, contraction of cardiac muscle is under autonomic nervous control. e. Like smooth muscle cells, some cardiac myocytes have pacemaker potentials.

Like skeletal muscle, contraction of cardiac muscle is under autonomic nervous control.

Which of the following is correct about the filling of the ventricles?

Most blood flows passively into the ventricles through open AV valves.

The rapid depolarization phase of the action potentials of myocardial contractile cells is due to which ion(s)?

Na+ only

What are Acetylcholine receptors?

Nicotinic Muscarinic

Which type of acetylcholine receptor is present on postganglionic neurons, and which type is present on the target tissues in autonomic pathways?

Nicotinic on the postganglionic neurons and muscarinic on the target tissues

The somatic nervous system and the parasympathetic nervous system both release acetylcholine (ACh) onto their target tissues. Do you predict that this would indicate that these two pathways carry out the same effects? Why or why not? Choose the best answer.

No, because the receptors found on the target tissue for each pathway are different.

Postganglionic neuron from the sympathetic nervous system.

Norepinephrine

Contraction of the atria results from which wave of depolarization on the ECG tracing?

P wave

Autonomic nervous system Controls:

Parasympathetic pathways Sympathetic pathways Adrenal sympathetic pathways

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.

Pressure in the atria would be greater than the pressure in the ventricles.

Match the name of the wave with the correlated event. A. P wave B. QRS complex C. T wave D. PR segment E. ST segment ventricular depolarization

QRS complex

If the radius of a tube decreases by half, what will happen to the resistance to fluid flow?

Resistance will increase 16 times.

Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?

SA node

Compared with skeletal and cardiac muscle, which of the following is not in smooth muscle? ____ in skeletal and cardiac muscle but not in smooth muscle.

Sarcomeres are

Calcium ions are removed from the sarcoplasm of the cardiac cell by the action of the sarcoplasmic reticulum (SR) Ca2+-ATPase pump and which other mechanism?

Sodium-calcium exchanger on the sarcolemma

Which event results in the first heart sound?

The AV valves close.

Which electrical event happens at the start of a cardiac cycle?

The SA node fires.

Which nervous system division has parasympathetic and sympathetic branches?

The autonomic division of the efferent nervous system

For what are If channels responsible in cardiac autorhythmic cells?

The pacemaker potential

How are cardiac muscle cells similar to smooth muscle cells?

They are electrically linked to one another.

Which blood vessels have the lowest blood pressure?

Veins

Compared to skeletal muscle, contraction of smooth muscle cells is

a slower response to a stimulus and sustained without fatigue.

Smooth muscle is present in the walls of

all vessel types except capillaries and venules.

A decrease in blood pressure at the arterial baroreceptors would result in which of the following?

an increase in heart contractility

Stimulation of the adrenal medulla would result in which of the following?

an increase in heart rate and contractility

Autorhythmic cells

are also called pacemakers because they set the rate of the heartbeat.

A typical action potential of a myocardial contractile cell lasts ________ millisecond(s).

at least 200

The division of the efferent nervous system that controls smooth and cardiac muscles and many glands is the __________ division.

autonomic

Which of the following best describes the direction and function of efferent signals?

away from the central nervous system, cause motor effects in glands or muscles

Stretch-sensitive mechanoreceptors known as ________ are located in some artery walls.

baroreceptors

In the heart, valves are located

between atria and ventricles and between ventricles and arteries.

In the capillaries, hydrostatic pressure (HP) is exerted by __________.

blood pressure

"Dual innervation" refers to an organ receiving

both sympathetic and parasympathetic nerves.

The net hydrostatic pressure (HP) is the hydrostatic pressure in the __________ minus hydrostatic pressure in the __________.

capillary; interstitial fluid

The term that describes the volume of blood circulated by the heart in one minute is

cardiac output (CO).

Where are the sensors for the arterial baroreceptor reflex located?

carotid sinus and aortic arch

Muscarine, a chemical produced by certain mushrooms, binds to muscarinic receptors mimicking the effect of acetylcholine. How do you think administering this chemical would change body function? The drug would _____________.

change the functionality of the heart change the functionality of certain exocrine and endocrine glands change the functionality of the smooth muscles within the digestive system

Match the following with its description. A. acetylcholine B. norepinephrine C. cholinergic nicotinic receptor D. adrenergic receptor E. cholinergic muscarinic receptor parasympathetic tissue receptor

cholinergic muscarinic receptor

Match the following with its description. A. acetylcholine B. norepinephrine C. cholinergic nicotinic receptor D. adrenergic receptor E. cholinergic muscarinic receptor target receptor for preganglionic neurons

cholinergic nicotinic receptor

The end of the plateau phase of cardiac contractile cell action potentials is due to the ________ of Ca2+ channels and ________ of K+ channels.

closing, opening

When blood pressure receptors sense a loss of blood pressure, they ________ their firing rate.

decrease

Drugs known as beta blockers will

decrease heart rate.

Which of the following would cause vasodilation of arterioles?

decreased activity of the sympathetic nervous system

How would a decrease in blood volume affect both stroke volume and cardiac output?

decreased stroke volume and no change in cardiac output

Which change will NOT result in increased blood flow to a tissue? a. decreased vessel diameter b. relaxation of precapillary sphincters c. increased blood pressure d. increased blood volume e. decreased peripheral resistance

decreased vessel diameter

The flattening of the action potentials of myocardial contractile cells, called the plateau phase, is due to a combination of ________ K+ permeability and ________ Ca2+ permeability.

decreasing, increasing

The P wave of an ECG corresponds to

depolarization of the atria.

What does the ECG wave tracing represent?

electrical activity in the heart

The term used to describe the amount of blood in the ventricle available to be pumped out of the heart during the next contraction is

end-diastolic volume (EDV).

The purpose of valves in the cardiovascular system is to

ensure that blood flows in one direction.

Which of the following would increase heart rate?

epinephrine and norepinephrine

The values obtained when measuring blood pressure, such as 120/80,

estimates the pressure in the major arteries during ventricular systole and diastole.

When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane?

fast calcium

A location outside of the central nervous system where autonomic signals can synapse

ganglion

Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane?

gap junctions

The depolarization of the pacemaker action potential spreads from cell to cell through

gap junctions.

Which of the following is/are targets of the efferent nervous system?

glands cardiac muscle skeletal muscle smooth muscle

What causes the aortic semilunar valve to close?

greater pressure in the aorta than in the left ventricle

If a physiological dose of an experimental drug was administered, and the subject responded to the chemical, which would indicate that this drug is an epinephrine agonist?

increase in fatty acids in the blood

If blood pressure is increased at the arterial baroreceptors, what would happen with the activity level of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS)?

increased PNS activity and decreased SNS activity

Reactive hyperemia is

increased blood flow following a period of reduced blood flow.

How would an increase in the sympathetic nervous system increase stroke volume?

increased contractility

By what mechanism would an increase in venous return increase stroke volume?

increased end diastolic volume

Which of the following would increase cardiac output to the greatest extent?

increased heart rate and increased stroke volume

The adrenal medulla is important to the sympathetic branch of the autonomic nervous system because it

is a source of catecholamines, is considered a modified sympathetic ganglion, and releases epinephrine and norepinephrine directly into the blood.

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.

isovolumetric contraction, ventricular ejection, isovolumetric relaxation

The mean arterial pressure (MAP) is important because

it represents the driving pressure for blood flow.

Blood flow to a tissue will increase if the

level of carbon dioxide at the tissue increases.

Restoring lost fluid from the capillaries back to the circulatory system is one of the major functions of the ________ system.

lymphatic

Capillaries are

microscopic vessels in which blood exchanges material with the interstitial fluid.

Compared to arteries, the velocity of flow of the blood through the capillaries is

much slower.

This protein is activated by the Ca2+-calmodulin complex to phosphorylate the myosin light chain protein.

myosin light chain kinase

Which net pressure draws fluid into the capillary?

net osmotic pressure

An important difference between single-unit and multiunit smooth muscle is the

numerous gap junctions in single-unit smooth muscle, which allow many cells to work together as a sheet.

The action potential in a cardiac contractile cell causes

opening of L-type calcium channels.

Which of the following are components of the efferent nervous system?

parasympathetic neurons somatic motor neurons sympathetic neurons

A neuron that receives an action potential from another neuron and then delivers that action potential to a smooth muscle

postganglionic autonomic neuron

One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion?

potassium

A neuron that delivers an action potential from the central nervous system to another neuron in the peripheral nervous system

preganglionic autonomic neuron

The driving force for blood flow is a(n) ________ gradient.

pressure

The importance of the plateau phase of the action potential of myocardial cells is in

preventing tetanus.

The cardiac output is equal to the

product of heart rate and stroke volume.

The colloid osmotic pressure in the capillary is caused by __________.

proteins in the blood

The difference between the systolic and diastolic pressures is called the

pulse pressure.

As blood vessel length increases,

resistance increases and flow decreases.

ECGs

show the summed electrical activity generated by all cells of the heart.

The AV node is important because it

slows the transmission of the electrical impulses to the ventricles in order for the atria to finish contracting.

A patient is born with a mutation in her calmodulin gene. This could affect the contraction of ________ muscles.

smooth.

A single neuron is stimulated at the central nervous system; this signal travels all the way to the target tissue, where the neurotransmitter acetylcholine is released onto the target tissue. The acetylcholine binds to a nicotinic receptor to induce skeletal muscle contraction. These steps describe the function of which branch of the efferent nervous system? Choose the best answer.

somatic

A neuron that delivers an action potential from the central nervous system to a skeletal muscle

somatic motor neuron

The volume of blood ejected from each ventricle during a contraction is called the

stroke volume.

The division of the autonomic nervous system that prepares the body for intense levels of activity and stress is the ________ division.

sympathetic

A heart rate of 125 beats per minute could be correctly termed

tachycardia

In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells?

the flow of positive ions from adjacent cells

Blood pressure is determined by measuring

the force exerted by blood in a vessel.

Edema is likely to occur when

the heart becomes an insufficient pump.

During ventricular ejection,

the ventricles are in systole.

Malnutrition can cause edema because

there are not enough nutrients for plasma protein synthesis.

Match the answers to the questions. A. true only for the sympathetic division B. true only for the parasympathetic division C. true for both divisions It contains cholinergic neurons.

true for both divisions

Match the answers to the questions. A. true only for the sympathetic division B. true only for the parasympathetic division C. true for both divisions Most preganglionic neurons originate in the thoracic and lumbar regions of the spinal cord.

true only for the sympathetic division

Match the answers to the questions. A. true only for the sympathetic division B. true only for the parasympathetic division C. true for both divisions The adrenal medulla is closely allied with this system.

true only for the sympathetic division

At an intercalated disc,

two cardiac muscle cells are connected by gap junctions.

Autorhythmic cells can generate action potentials spontaneously because they have

unstable membrane potentials.

Relative to skeletal muscle, smooth muscle

uses less energy to generate a given amount of force, can sustain contractile force without fatigue and uses calcium from the sarcoplasmic reticulum and extracellular space.

Which would decrease peripheral resistance?

vasodilation

Reabsorption of fluid into the capillary takes place at the arterial end or venous end of the capillary?

venous

What does the QRS complex represent in the ECG wave tracing?

ventricular depolarization

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.

ventricular diastole

Repolarization of an autorhythmic cell is due to the opening of which channels?

voltage-gated potassium channels

In which situation would end-systolic volume (ESV) be the greatest?

when parasympathetic stimulation of the heart is increased

In which situation would the stroke volume be the greatest?

when venous return is increased