Human Heart Anatomy

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Questions and Answers

Where is the heart located in the body?

In the abdominal cavity

In the thoracic cavity in the mediastinum (correct)

In the neck

In the pelvic region

How much does the heart typically weigh in women?

225 g (correct)

250 g

150 g

300 g

What is the function of the valves in the heart?

To increase heart rate

To prevent backflow of blood (correct)

To pump blood throughout the body

To regulate blood pressure

What is the outer layer of the heart wall called?

Pericardium Signup and view all the answers

Which valve has two cusps?

Mitral valve Signup and view all the answers

What is the function of the septum in the heart?

To separate the heart into right and left sides Signup and view all the answers

What happens to the valves during ventricular systole?

They close to prevent backflow Signup and view all the answers

What is the middle layer of the heart wall composed of?

Specialized cardiac muscle Signup and view all the answers

What is the point of division of the brachial artery?

Into the radial and ulnar arteries Signup and view all the answers

Which of the following veins drains blood from the rectum and descending colon?

Inferior mesenteric vein Signup and view all the answers

What is the route of venous blood from the digestive system to the liver?

Via the portal vein Signup and view all the answers

Which of the following arteries is not in the forearm?

Axillary artery Signup and view all the answers

Where can the radial pulse be felt?

In front of the radius bone Signup and view all the answers

What is the final destination of venous blood from the portal circulation?

The inferior vena cava Signup and view all the answers

What is the primary function of the pulmonary circulation?

To exchange gases between the blood and air in the lungs Signup and view all the answers

Where does the pulmonary artery divide into left and right pulmonary arteries?

In the upper part of the right ventricle of the heart Signup and view all the answers

What is the purpose of the capillaries in the lungs?

To exchange gases between the blood and air in the lungs Signup and view all the answers

What is the primary function of the heart in the cardiovascular system?

To pump blood constantly Signup and view all the answers

How many pulmonary veins leave each lung?

Two Signup and view all the answers

What are the two main parts of the cardiovascular system?

The heart and blood vessels Signup and view all the answers

What is the name of the artery that rises from the heart and is about 5 cm long?

Ascending aorta Signup and view all the answers

What is the process that occurs in the pulmonary circulation?

Exchange of oxygen and carbon dioxide Signup and view all the answers

What are the two branches of the aorta that supply the myocardium?

Left and right coronary arteries Signup and view all the answers

What is the name of the part of the aorta that lies above the diaphragm?

Thoracic aorta Signup and view all the answers

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

To pump blood to the rest of the body Signup and view all the answers

What is the name of the vein that returns oxygenated blood from the lungs to the heart?

Pulmonary vein Signup and view all the answers

What are the three layers of tissue in the walls of arteries and arterioles?

Outer fibrous, middle smooth muscle and elastic, and inner endothelium Signup and view all the answers

What is the main difference between the walls of arteries and veins?

Arteries have thicker walls than veins Signup and view all the answers

What is the purpose of valves in some veins?

To prevent the backflow of blood Signup and view all the answers

What happens to veins when they are cut?

They collapse Signup and view all the answers

What is the origin of the left common carotid artery?

Directly from the arch of the aorta Signup and view all the answers

Which artery supplies the superior part of the scalp?

Temporal artery Signup and view all the answers

What is the role of the vertebral arteries in the circulation of blood to the head and neck?

Forming the circle of Willis Signup and view all the answers

Which artery is responsible for supplying the tongue and mouth?

Lingual artery Signup and view all the answers

Where do the external and internal jugular veins begin?

At the level of the angle of the jaw Signup and view all the answers

What is the origin of the right subclavian artery?

From the brachiocephalic artery Signup and view all the answers

Which of the following arteries is involved in the circulation of blood to the upper limb?

Subclavian artery Signup and view all the answers

What is the role of the circulus arteriosus or the circle of Willis?

Supplying the brain with arterial blood Signup and view all the answers

Study Notes

Heart Structure

The heart is about 10 cm long, weighs around 225g in women and 310g in men, and is roughly the size of a fist.
It lies in the thoracic cavity in the mediastinum, with its apex in the left of the midline at the level of the 5th intercostal space.

Associated Organs

Inferiorly, the apex of the heart rests on the central tendon of the diaphragm.
Superiorly, the heart is associated with great blood vessels, including the aorta, superior vena cava, pulmonary artery, and pulmonary veins.
Posteriorly, the heart is associated with the oesophagus, trachea, left and right bronchus, descending aorta, inferior vena cava, and thoracic vertebrae.
Laterally, the heart is associated with the lungs, with the left lung overlapping the left side of the heart.
Anteriorly, the heart is associated with the sternum, ribs, and intercostal muscles.

Heart Wall

The pericardium is the outer layer of the serous membrane, consisting of the parietal pericardium (outer layer) and visceral pericardium (inner layer).
The myocardium is composed of specialized cardiac muscle found only in the heart.
The endocardium consists of flattened epithelial cells and is continuous with the endothelium lining the blood vessels.

Interior of the Heart

The septum divides the heart into the right and left sides.
The atrioventricular valve divides each side of the heart into the upper atrium and the ventricle below.
The right atrioventricular valve (tricuspid valve) has three flaps or cusps.
The left atrioventricular valve (mitral valve) has two cusps.

Cardiovascular System

The cardiovascular system is divided into two main parts: the heart and blood vessels.
The heart pumps blood into two anatomically separate systems of blood vessels: the pulmonary circulation and the systemic circulation.
The right side of the heart pumps blood to the lungs (pulmonary circulation), while the left side of the heart pumps blood to the rest of the body (systemic circulation).

Blood Vessels

Arteries and arterioles transport blood away from the heart and have three layers: outer fibrous tissue, middle smooth muscle and elastic tissue, and inner endothelium.
Veins return blood to the heart at low pressure, with thinner walls than arteries, and may possess valves to prevent backflow.
Capillaries are the site of gas exchange and nutrient exchange between blood and tissues.

Pulmonary Circulation

Deoxygenated blood from the right ventricle flows through the pulmonary artery to the lungs, where gas exchange occurs.
Oxygenated blood returns to the left atrium through the pulmonary veins.

Systemic Circulation

Oxygenated blood from the left ventricle flows through the aorta and its branches to the rest of the body.
Deoxygenated blood returns to the right atrium through the superior and inferior vena cavae.

Aorta

The aorta is divided into three parts: ascending aorta, arch of the aorta, and descending aorta in the thorax.
The ascending aorta gives rise to the right and left coronary arteries, which supply the myocardium.
The arch of the aorta gives rise to the brachiocephalic artery, left common carotid artery, and left subclavian artery.

Arterial Supply to the Head and Neck

The brachiocephalic artery branches into the right subclavian artery and right common carotid artery.
The left common carotid artery arises directly from the arch of the aorta.
Each common carotid artery divides into an internal carotid artery and an external carotid artery.
The internal carotid artery supplies the brain, while the external carotid artery supplies the superficial tissues of the head and neck.

Venous Return from the Head and Neck

Venous blood from the head and neck returns through deep and superficial veins, including the external and internal jugular veins, which empty into the subclavian vein.

Circulation to the Upper Limb

The right subclavian artery arises from the brachiocephalic artery, while the left subclavian artery arises from the arch of the aorta.
The axillary artery continues as the brachial artery, which divides into the radial and ulnar arteries.

Portal Circulation

The portal vein is formed by the splenic, inferior mesenteric, superior mesenteric, gastric, and cystic veins, which drain blood from the digestive system, spleen, and pancreas to the liver.
The portal vein then enters the general circulation via the inferior vena cava.

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Description

Learn about the structure and position of the human heart, including its size, weight, and surrounding organs.