test 1b anatomy 2

________ is to slow heart rate as ________ is to fast heart rate.

1- bradycardia 2- tachycardia

In cardiac muscle, the fast depolarization phase of the action potential is the result of ________ membrane permeability to ________ ions.

1- increased 2- sodium

_____ is to contraction and ________ is to relaxation

1- systole 2- diastyle

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

Depolarization of the ventricles is represented on an electrocardiogram by the

QRS complex

Blood returning to the heart from the pulmonary circuit first enters the

left atrium

Rupture of the papillary muscles in the left ventricle may result in

mitral valve regurgitation of blood into atrium, and/or prolapsed valve

Tetanic muscle contractions don't occur in a normal cardiac muscle because

open calcium channels cause the refractory period to last until the muscle relaxes

Acetylcholine slows the heart because it

opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly.

Chemoreceptor reflexes respond to

pH, oxygen, carbon dioxide

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

If the pacemaker cells in the SA node become more permeable to potassium ions

the membrane will hyperpolarize/depolarize more slowly, and the heart rate will decrease

Tetanic muscle contractions don't occur in a normal cardiac muscle because

the refractory period lasts until the muscle relaxes

The T wave on an ECG tracing represents

ventricular repolarization

The hormone that produces cardiovascular effects similar to activation of the sympathetic nervous system is

epinephrine

adrenal medulla secretes

epinephrine

describe how autoregulation automatically adjusts tissue perfusion to your biceps brachii when you are lifting weights.

Oxygen decreases Carbon dioxide increases Lactic acid increases vasodilates and takes more blood into tissue

A person notices his or her heart beat because he or she senses blood being pumped by the heart. Excessive caffeine intake can lead to irregular heart rhythms (arrhythmias) that patients perceive as "skipped beats." Given that caffeine is a stimulant, which of the following mechanisms best explains the reason for the feeling that the heart skipped a beat?

Purkinje fibers initiate spontaneous action potentials, which cause the ventricles to contract early.

If there is a complete block between the SA node and the AV node, how would the ECG be affected?

The rate of P waves will be faster than the rate of QRS complexes.

Each of the following will lead to a decrease in blood

increased levels of ANP (atrial natriuretic peptide). decrease in blood volume. reduced thirst. decreased peripheral resistance.

Sensory neurons that are part of chemoreceptor reflexes are found in the

medulla oblongata

Increased levels of carbon dioxide in the blood will result in decreased

parasympathetic stimulation of the heart.

The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important?

so blood is forced upward, toward the semilunar valves

Arteriosclerosis can lead to

stroke coronary heart disease hypertension

Analysis of the electrocardiogram can reveal all of the following except the

stroke volume

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

stroke volume

If the connection between the SA node and AV node becomes blocked,

the ventricles will beat slower, because the AV node depolarizes slower than the SA node

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

voltage-gated potassium channels

Negative Feedback in the HPT Axis: Which of the following is NOT produced by high levels of Thyroid Hormones in the blood?

Increased secretion of Thyroid Hormones due to reduced TSH and TRH

the middle layer in the heart wall is composed of:

cardiac muscle cells

Hypothalamus secretes

corticotropin releasing hormone

Drugs known as calcium channel blockers such as nifedipine can be used to

decrease the force of cardiac contraction.

Which of the following would have the greater effect on vascular resistance?

decreasing the diameter of a blood vessel by 1/2

The P wave of the electrocardiogram is a signal from

depolarization of the atria.

The ________ is the volume of blood in a ventricle at the beginning of systole.

end-diastolic volume

The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill.

end-systolic volume

The normal pacemaker of the heart is located in

sinoatrial node

how many pulmonary veins are there?

4

lisrt the intrinsic muscles conduction system in order

1- SA node 2- AV node 3- AV bundle 4- Branches 5- Purkinje fibers

anterior pituitary gland secretes

thyroid stimulating hormone

baroreflex:

Baroreceptors inform the medulla oblongata about changes in blood pressure, producing a programmed and rapid response to return the body to equilibrium. A larger blood volume will stretch the aorta, and the baroreceptors will trigger the Cardioinhibitory Center of the brainstem in response. Norepinephrine from the post-ganglionic neuron will trigger SA Node Pacemaker cells to depolarize more quickly, therefore increasing heart rate.

A portal system is defined as a circulatory pathway in which blood passes through TWO capillary beds before returning to the right atrium, not one capillary bed

The hypothalamus releases hormones into the first capillary bed of a portal system, which are then delivered to a second capillary bed in the Anterior Pituitary gland.

Myogenic autoregulation can be defined as:

The main component of this reflex is when the baroreceptors release nitric oxide on the aorta and carotid arteries, leading to an immediate vasodilation and decrease in blood pressure.

When chemoreceptors in the carotid or aortic bodies detect INCREASED oxygen or DECREASED carbon dioxide:

The medulla oblongata causes a decrease in Heart Rate and vasodilation

Collateral ganglia contain the cell bodies of sympathetic neurons innervating tissues and organs in which cavity?

abdominopelvic

Homeostatic mechanisms in response to blood loss include all of the following

activation of ADH secretion. activation of aldosterone secretion. increased thirst and water intake. uptake of interstitial fluid due to reduced capillary pressure.

Hypothalamus (via posterior pituitary) secretes

antidiuretic hormone

Sympathetic innervation of the heart:

arrives in postganglionic fibers within the cardiac nerves.

Blood flow to a tissue will increase if the

arterioles dilate

the ear like extension of the atrium is the:

auricle

________ is the regulation of blood flow by local mechanisms within a capillary bed.

autoregulation

Total peripheral resistance is related to all including

blood viscosity. the flow characteristics. the length of a blood vessel. blood vessel diameter

The heart is innervated by ________ nerves.

both parasympathetic and sympathetic

The long plateau phase of the cardiac muscle action potential is due to

calcium channels remaining open

the function of the atrium is to:

collect blood and pump blood to the ventricle

autonomic motor neurons

conduct impulses to smooth and cardiac muscles and glands

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

fast calcium

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

gap junctions

Pacemaker cells in the SA node

generate action potentials that spread to the myocardium.

Stimulation of the aortic baroreceptors results in

increased activity by the parasympathetic nervous system.

Which of the following factors will increase the net filtration pressure to move fluid out of capillaries?

increased blood hydrostatic pressure decreased tissue hydrostatic pressure decreased plasma albumen

contractions of the pappilary muscles:

prevent the atrioventricular valves from reversing into the atria.

Natriuretic peptide release by the heart:

results in increased sodium loss in urine.

Blood returning to the heart from the systemic circuit first enters the:

right atrium

parasympathetic division

About 75% of all parasympathetic control travels along the Vagus Nerve, cranial nerve X. Its neurons release ACh from both the pre- and post-ganglionic fibers. Because of its long pre-ganglionic fibers, it can innervate many organs simultaneously. It is also called the craniosacral division, because its fibers emerge from the brainstem and the sacral region.

As the heart rate slows, ________ get(s) longer.

diastole

Each of the following factors will increase cardiac output except

increased parasympathetic stimulation.

Which of the following would increase heart rate?

increased sympathetic stimulation of SA node decreased parasympathetic stimulation of SA nodal fibers increased levels of norepinephrine and/or epinephrine faster depolarization of the pacemaker potential.

Each of the following changes will result in increased blood flow to a tissue:

increased vessel diameter. relaxation of precapillary sphincters. increased blood pressure. decreased peripheral resistanc