A&P Unit 7: The Cardiovascular System

TEK AP.14B : The myocardium is the -

• sac surrounding the heart

• thick, muscular wall of the heart

• inner lining of the heart

• septum between the chambers of the heart

Answer explanation

The myocardium is the thick, muscular wall of the heart, responsible for its contraction and pumping blood. It is distinct from the pericardium (sac), endocardium (inner lining), and septum (divides chambers).

TEK AP.14B : The bicuspid (mitral) valve is located between the -

• right and left ventricles

• left atrium and left ventricle

• left and right atria

• left vetricle and the aorta

Answer explanation

The bicuspid (mitral) valve is located between the left atrium and left ventricle, allowing blood to flow from the atrium to the ventricle while preventing backflow.

TEK AP.14B : The fluid-filled, double-walled sac that surround the heart is called the -

• pericardium

• endocardium

• myocardium

• epicardium

Answer explanation

The pericardium is the fluid-filled, double-walled sac that surrounds the heart, providing protection and reducing friction during heartbeats. The other options refer to different heart structures: endocardium (inner layer), myocardium (muscle), and epicardium (outer layer).

TEK AP.14B : The heart is flanked on either side by the -

• diaphragm

• lungs

• hips

• sternum

Answer explanation

The heart is located between the lungs in the thoracic cavity. The lungs are essential for respiration and are positioned on either side of the heart, making them the correct answer.

TEK AP.14B : The pacemaker of the heart is the -

• Mitral valve

• atrioventricular node

• sinoatrial node

• bundle of His

Answer explanation

The sinoatrial node (SA node) is the heart's natural pacemaker, responsible for initiating the electrical impulses that regulate heartbeats. The other options do not serve this primary function.

TEK AP.14G: The SA node is -

• located at the top of the right atrium

• located in the brain

• located near the bundle of His

• the origin of Purkinje fibers

Answer explanation

The SA node, or sinoatrial node, is located at the top of the right atrium. It serves as the heart's natural pacemaker, initiating the electrical impulses that regulate heartbeats.

TEK AP.14G: Sympathetic nerve fibers stimulate the SA node, which -

• increases the heart rate

• decreases the heart rate

• causes the ventricles ot contract

• makes the heart rate irregular

Answer explanation

Sympathetic nerve fibers release neurotransmitters that stimulate the SA node, leading to an increase in heart rate. This response prepares the body for 'fight or flight' situations, making 'increases the heart rate' the correct choice.

Tags

NGSS.HS-LS1-3

TEK AP.14G: Which of the following is not considered a component of the heart conduction system?

• sinoatrial (SA) node

• epicardium

• Purkinje fibers

• atrioventricular (AV) node

Answer explanation

The epicardium is the outer layer of the heart and not part of the conduction system. The sinoatrial (SA) node, atrioventricular (AV) node, and Purkinje fibers are all essential components of the heart's conduction system.

TEK AP.14G: The ___________ which are sensitive to pressure, are located in the aortic arch and carotid arteries.

• baroreceptors

• nueroreceptors

• epicardium

• Purkinje Fibers

Answer explanation

The correct answer is 'baroreceptors' as they are specialized sensory receptors located in the aortic arch and carotid arteries that detect changes in blood pressure.

TEK AP.14G: What nervous system is in charge of decreasing someone's heart rate?

• sympathetic nervous system

• parasympathetic nervous system

• sensory nervous system

• optical nervous system

Answer explanation

The parasympathetic nervous system is responsible for decreasing heart rate, promoting a state of rest and relaxation, in contrast to the sympathetic nervous system, which increases heart rate during stress or activity.