the cardiovascular system: heart
The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. bundle branches The sequence in which excitation would move through this system is which of the following?
4,3,2,5,1 (SA node, AV node, AV bundle, bundle branches, purkinje fibers)
The total volume of blood in the body of an adult male is approximately ________ liters.
5-6
Secretory cells of the adenohypophysis release all of the following except: A. TSH B. OXT C. LH D. GH E. FSH
B
An activated G protein can trigger all of the following except
an increase in ATP production
The earlike extension of the atrium is the
auricle
Erythropoiesis is stimulated when
both oxygen levels in the blood decrease and blood flow to the kidney declines.
The heart is innervated by ________ nerves.
both parasympathetic and sympathetic
Which parts of the following statement are true: The AV node delivers the stimulus to the AV bundle, located within the interventricular septum.
both parts of the statement are true
The ________ separate(s) the two ventricles.
interventricular septum
blood is supplied to the left atrium by the
left coronary artery
Most of the mass of the heart lies to the ________ the midline.
left of
The muscle layer of the heart is the
myocardium
When the semilunar valves close, the AV valves then
open
Acetylcholine slows the heart because it
opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly.
The hormone(s) that may be slowly administered by intravenous drip to accelerate labor and delivery is/are
oxytocin
Depolarization of the atria corresponds to the ECG's
p wave
Rupture of the papillary muscles in the left ventricle may result in any of the following except
pulmonary valve stenosis.
Tetanic muscle contractions don't occur in a normal cardiac muscle because
the refractory period lasts until the muscle relaxes.
Muscular ridges on the inner surface of the ventricles are called
trabeculae carneae
another term for epicardium
visceral pericardium
The long plateau phase of the cardiac muscle action potential is due to
voltage-gated calcium channels remaining open
At a heart rate of 60 beats/minute, a cardiac cycle lasts
1 second
Cardiac output can be increased by all of the following except A. decreasing ejection fraction. B. increasing stroke volume. C. increasing ejection fraction. D. increasing heart rate. E. decreasing end-systolic volume.
A
Hormonal actions on cells can affect all of the following except: A. decrease levels of calcium ions. B. increase ATP production. C. increase levels of cAMP. D. decrease gene transcription. E. decrease hormone release through negative feedback.
A
Activation of the renin-angiotensin system would result in all of the following except A. elevated blood pressure. B. increased blood volume. C. increased water retention. D. increased urine production. E. increased retention of sodium ions at the kidney
D
During the isovolumetric contraction phase of ventricular systole, the
None of these answers are correct (i think)
A slower-than-normal heart rate is called
bradycardia (under 60 BPM)
The function of hemoglobin is to
carry oxygen
The first blood vessels to branch from the aorta are the ________ arteries.
coronary
The P wave of the electrocardiogram is a signal from
depolarization of the atria
The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill.
end-systolic volume
The pulmonary veins carry blood to the
heart
Which of the following proteins functions to store or transport oxygen?
hemoglobin
The atrioventricular valves permit blood flow
in one direction only.
