Human Heart Anatomy and Circulatory System: Key Concepts for Biology

What is the location of the heart within the thoracic cavity?

The heart is located near the midline of the thoracic cavity in the mediastinum.

What are the two aspects of the heart?

The base (superior aspect) and the apex (inferior aspect).

What structure surrounds the heart and what is its function?

The heart is housed by the pericardium, which produces fluid to maintain a low-friction environment.

How many chambers does the heart have?

The heart has four chambers: two atria (left and right) and two ventricles (left and right).

What is the function of the right side of the heart?

The right side of the heart contributes to the pulmonary circuit, pumping deoxygenated blood to the lungs.

What is the function of the left side of the heart?

The left side of the heart is responsible for the systemic circuit, circulating oxygenated blood to the body.

What type of muscle is cardiac muscle and how does it differ from skeletal and smooth muscle?

Cardiac muscle is involuntary and striated, containing intercalated discs for rapid communication between cells.

What are the heart sounds commonly referred to as?

The heart sounds are known as 'lubb dubb' or 'lup dup'.

What causes the 'lubb' sound in the heart?

'Lubb' is caused by the closure of the mitral and tricuspid valves during ventricular contraction.

What causes the 'dubb' sound in the heart?

'Dubb' is caused by the closure of the semilunar valves (aortic and pulmonary) during ventricular relaxation.

Where are the aortic valve sounds best heard?

Aortic valve sounds are best heard in the 2nd intercostal space at the right sternal margin.

What are the three large branches that come off of the aorta?

Brachiocephalic, left common carotid, and left subclavian arteries.

What is the difference between AV valves and semilunar valves?

AV valves have leaflets attached and are located between the upper and lower chambers, while semilunar valves are crescent-shaped.

What physical differences are noted when comparing the left ventricle to the right ventricle?

The left ventricle has a thicker wall and is more muscular than the right ventricle.

What is the function of chordae tendineae?

Chordae tendineae are string-like cords that anchor the mitral and tricuspid valves.

Which valves are located on the right side of the heart?

The tricuspid and pulmonary valves.

Which valves are located on the left side of the heart?

The mitral and aortic valves.

What regions does the Superior Vena Cava drain blood from?

The head, neck, arms, shoulders, and upper chest.

What is systole?

Systole is the phase of the cardiac cycle when the heart contracts to pump blood out.

What is diastole?

Diastole is the phase of the cardiac cycle when the heart relaxes.

What is the role of the SA node in the heart?

The SA node is the natural pacemaker of the heart, initiating the electrical signals for heart contractions.

What does the QRS complex in an EKG represent?

The QRS complex represents ventricular depolarization.

What does the T wave in an EKG represent?

The T wave represents ventricular repolarization.

What is the function of Purkinje fibers?

Purkinje fibers conduct electrical impulses to the myocardial cells, facilitating coordinated contraction.

Where is the SA node located?

In the upper wall of the right atrium, near the superior vena cava.

What is the function of the AV node?

Acts as a gatekeeper for the heart's electrical signal, delaying it to allow the atria to finish contracting.

What does an EKG test measure?

It shows the electrical activity of the heart.

What do the P, QRS, and T waves in an EKG correspond to?

P: Atrial depolarization; QRS: Ventricular depolarization; T: Ventricular repolarization.

What is considered a normal blood pressure?

120/80 mmHg.

What are the main types of blood vessels?

Arteries (carry blood away from the heart) and veins (return blood to the heart).

What is the role of capillaries in the circulatory system?

Gas exchange occurs in capillaries, where oxygen is picked up and carbon dioxide is released.

What are the three tunics of blood vessels?

Tunica intima (interna), tunica media, and tunica externa (adventitia).

How do arteries differ from veins?

Arteries carry oxygenated blood away from the heart, while veins carry deoxygenated blood back to the heart.

What is the function of valves in veins?

To control the directional flow of blood back to the heart.

Where does the coronary artery originate?

It arises from the root of the aorta.

What are the three main branches that come off of the aorta?

Brachiocephalic trunk, left common carotid artery, and left subclavian artery.

What are the six arteries that branch off of the external carotid artery?

Superior thyroid, lingual, facial, ascending pharyngeal, occipital, and posterior auricular arteries.

What is the difference between systolic and diastolic pressure?

Systolic pressure is the force when blood is pumped out; diastolic pressure is when the heart is filling with blood.

Which artery is used to determine blood pressure with a cuff?

The brachial artery.

How is the radial pulse measured?

By placing fingers over the radial artery at the wrist and feeling for expansion.

What is the proper technique for measuring blood pressure?

Use a blood pressure cuff aligned with the brachial artery and listen for Korotkoff sounds with a stethoscope.

What happens to blood pressure immediately after standing?

Blood pressure may temporarily drop before stabilizing.

What is the significance of the carotid artery?

It contains baroreceptors and should only be palpated one at a time.

What are the common sites for pulse palpation?

Temporal, facial, carotid, brachial, radial, femoral, popliteal, posterior tibial, and dorsalis pedis arteries.

What is the role of the tunica media in arteries?

It contains a thick layer of smooth muscle that provides integrity and resilience.

What is the purpose of the capillary network?

To facilitate gas exchange between blood and tissues.

What is the significance of the aortic arch?

It gives rise to major arteries that supply blood to the head, neck, and arms.

How do arteries maintain blood flow?

Through their thick muscular walls that allow for contraction and resilience.

What is the function of the pulmonary capillaries?

To pick up oxygen and release carbon dioxide from the blood.