BMS 251 exam 1 practice questions

The AV node fires causing the signal to travel into the ______________ as it passes through the _________________.

AV bundle branches, interventricular septum

What is the correct order of mechanical events associated with cardiac muscle contraction?

Calcium entry into the sarcoplasm, calcium binds to troponin, muscle contracts, closing of calcium channels, calcium released from troponin, muscle relaxes

This results from a slow inflow of Na+ without a compensating outflow of _______.

K+

Place the locations of the heart's conducting system in order, beginning with the location where the heartbeat is initiated.

SA node, left and right bundle branches, AV bundle, purkinje fibers, AV node

What are the primary variables influencing stroke volume (SV)?

afterload, venous return or preload, contractility or inotropic agents

Which of the following variables would affect the concentration of a circulating hormone in the blood? [ ] the amount of hormone being released [ ] enzymatic degradation of the hormone [ ] excretion of the hormone by the kidneys [ ] uptake of the hormone by target cells [ ] whether or not the hormone has a carrier protein [ ] all the above would influence the concentration of a circulating hormone in the blood

all the above would influence the concentration of a circulating hormone in the blood

The hypothalamus controls the ________ pituitary gland through hormonal communication, while it controls the ________ pituitary through neuronal communication.

anterior, posterior

Left ventricular contraction propels blood through which valve?

aortic valve

Depolarization then arrives at the ________ node located in the inferior interatrial septum.

atrioventricular

Chemical messengers that influence the activity of the same cell that releases them are ___________ chemical messengers, while chemical messengers that influence the activity of another cell are ___________ chemical messengers.

autocrine, paracrine

which primary ion movement is responsible for the plateau phase?

calcium influx and potassium efflux

Water-soluble hormones ______ pass through the cell membrane.

cannot

__________________ hormones are released into the blood stream and have the potential to act on distant cells throughout the body.

circulating hormones

When blood is flowing out of the left ventricle, the bicuspid valve is __________ and the aortic semilunar valve is __________.

closed, open

This upward drift towards a gradual ____________ is called the pacemaker potential.

depolarization

Hormone ___________ is the process that deals with enzymatic degradation of hormones and removal of the hormone from the blood by excretion or uptake into the target cells.

elimination

one example of a hormone that binds to membrane-bound receptors is __________

epinephrine

True or false: As compared to the nervous system, the endocrine system has a faster response time, a more localized range of effects and a short duration of action.

false

True or false: Water-soluble hormones do not readily dissolve within the aqueous environment of the blood and require carrier proteins to be transported in the blood.

false

true or false: Atrial contraction accounts for most of the ventricular filling.

false

true or false: During the refractory period of cardiac muscle, the cell is likely to generate another action potential

false

true or false: In modifying cardiac activity, the parasympathetic innervation comes from the cardioacceleratory center in the brain and the sympathetic innervation comes from the cardioinhibitory center in the brain.

false

true or false: The only arteries in the body that carry oxygen-poor blood are the coronary arteries.

false

true or false: hormonal stimulation causes the release of hormones by direct stimulation from the nervous system

false

How many pulmonary veins are there?

four

Neighboring cardiac muscle cells in the walls of heart chambers have specialized protein channels that electrically link the cells together, permitting the immediate passage of electrical impulses from cell to cell. These channels are called ________ _______.

gap junctions

The release of thyroid hormone from the thyroid gland in response to Thyroid stimulating hormone is an example of ........

hormonal stimulation

transcription of mRNA is the result of the binding of _______ soluble hormones

lipid

water-soluble hormones bind to ___________ receptors

membrane-bound

Lipid-soluble hormones bind to ________ receptors

nuclear

From the _________, the wave of depolarization disperses through the myocardium of the atria.

pacemaker

During the _____________ phase of a cardiac myocyte action potential, Calcium inflow is matched by potassium outflow, and thus no major electrical change occurs. This phase is responsible for the long refractory period of cardiac myocytes.

plateau

Antidiuretic hormone (ADH) is released by the........

posterior pituitary

which primary ion movement is responsible for repolarization?

potassium efflux

Making a U-turn at the apex of the heart, the signals are then carried by the ____________ through the exterior walls of the ventricles.

purkinje fibers

This is because the cells of the SA node do not have a stable ________ membrane potential like skeletal muscles or neurons.

resting

Oxygen-poor blood enters which chamber of the heart?

right atrium

The contraction of the heart begins with autorhythmic depolarization of the _______ node located in the superior portion of the posterior atrial wall.

sinoatrial

which primary ion movement is responsible for depolarization?

sodium influx

The SA node ___________ fires at regular intervals.

spontaneously

Which of the following hormone examples are lipid soluble? Select all that apply. [ ] steroid hormones [ ] catecholamines [ ] protein hormone [ ] polypeptide hormones

steroid hormones, polypeptide hormones

Which of the following is not true for ventricular systole? [ ] the ventricles contract [ ] the AV valves close [ ] the semilunar valves open [ ] the ventricles relax [ ] blood flows through the aorta and the pulmonary trunk

the ventricles relax

an example of a hormone that binds to a nuclear receptor is __________

thyroid hormone

True or false: Paracrine hormones are hormones that exert their effect by binding to receptors on neighboring cells without circulating through the blood. Autocrine hormones are hormones that affect the same cell that produced them.

true

true or false: Cardiac output (CO) is equivalent to heart rate (HR) multiplied by stroke volume (SV).

true

true or false: Endocrine cells are organized in two general ways: either as a single organ with only endocrine function or as cells housed in small clusters within organs that have some other primary function.

true

true or false: SA nodal cells are unique in that they exhibit autorhythmicity, meaning they are capable of depolarizing and firing an action potential spontaneously without any external influence.

true

true or false: The general function of the cardiovascular system is to transport blood throughout the body to allow the exchange of respiratory gases, nutrients, and waste products between the blood of capillaries and body cells, through the continual pumping action of the heart and vessels.

true

true or false: The plateau phase of the action potential in cardiac muscle delays repolarization to the resting membrane potential; therefore the refractory period is prolonged

true

true or false: The ventricles begin to fill during ventricular diastole.

true

Unidirectional flow in the heart is ensured because the heart contains __________ that prevent backflow.

valves

The atrioventricular valves open during

ventricular diastole

The semilunar valves close during

ventricular diastole

During the depolarization phase of cardiac muscle

voltage gated sodium channels open

Their membrane potential starts at about _______ mV and drifts upward

-60

What are the individual ion contributions to the resting membrane potential (RMP) of the SA nodal cells? Check all that apply.

-greater concentration of Na+ outside of the cell -greater concentration of K+ inside the cell -calcium (Ca2+) gradient with more calcium outside the cell