#1
Which chamber of the heart receives oxygenated blood from the lungs?
Left atrium
ExplanationReceives oxygen-rich blood from the lungs before pumping it into the left ventricle.
#2
What is the term for the volume of blood ejected by the left ventricle of the heart in one contraction?
Stroke volume
ExplanationAmount of blood pumped out of the heart with each beat.
#3
Which of the following is a function of the endothelium in blood vessels?
Release of nitric oxide to regulate vessel dilation
ExplanationEndothelium produces nitric oxide, a molecule that causes blood vessels to widen.
#4
What is the primary function of antidiuretic hormone (ADH) in the context of blood pressure regulation?
Increasing water reabsorption in the kidneys
ExplanationHelps kidneys retain water, increasing blood volume and therefore blood pressure.
#5
Which blood vessel carries oxygenated blood from the heart to the rest of the body?
Aorta
ExplanationLargest artery in the body that delivers oxygen-rich blood to various tissues.
#6
What is the primary function of the sinoatrial (SA) node in the heart?
Generate electrical impulses to initiate heart contractions
ExplanationInitiates heartbeat by generating electrical signals that cause heart muscle contractions.
#7
Which blood vessel carries deoxygenated blood from the body to the heart?
Superior vena cava
ExplanationReturns deoxygenated blood from the upper body to the right atrium of the heart.
#8
Which blood vessels have thin walls that allow for the exchange of nutrients and gases between the blood and surrounding tissues?
Capillaries
ExplanationMicroscopic vessels where oxygen and nutrients diffuse into tissues and waste products enter the bloodstream.
#9
What is the Frank-Starling law of the heart related to?
Control of stroke volume
ExplanationHeart automatically adjusts the force of its contractions based on how much blood it receives.
#10
What is the role of the renin-angiotensin-aldosterone system (RAAS) in blood pressure regulation?
Stimulating aldosterone release to retain sodium and water
ExplanationHelps regulate blood pressure by controlling levels of salt and water in the body.
#11
Which factor contributes to the development of atherosclerosis?
Low-density lipoprotein (LDL) cholesterol
ExplanationBuildup of LDL cholesterol in arteries can lead to plaque formation, narrowing blood vessels.
#12
What is the main factor that determines resistance to blood flow in the circulatory system?
Blood viscosity
ExplanationThickness of blood affects how easily it flows through blood vessels.
#13
Which hormone is responsible for increasing heart rate and contractility during the 'fight or flight' response?
Epinephrine
ExplanationReleased during stress to increase heart rate and strength of heart contractions.
#14
Which of the following is NOT a factor that can influence blood pressure?
Sweating
ExplanationWhile sweating regulates body temperature, it doesn't directly affect blood pressure.
#15
What is the term for the period of relaxation and filling of the heart chambers during the cardiac cycle?
Diastole
ExplanationHeart muscle relaxes, allowing chambers to fill with blood.
#16
What is the term for the volume of blood that returns to the heart during ventricular relaxation?
End-diastolic volume
ExplanationAmount of blood in the ventricles before they contract again.
#17
Which hormone plays a key role in regulating blood calcium levels and indirectly influences blood vessel constriction?
Parathyroid hormone
ExplanationRegulates calcium levels, which affect muscle contraction, including blood vessel constriction.