Heart Anatomy and Function

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Questions and Answers

What is the primary function of the right side of the heart in relation to the lungs?

Pumps deoxygenated blood to the lungs for oxygenation (correct)

Pumps oxygenated blood to the body

Drains waste products from the heart

Pumps blood through the coronary arteries

Which artery branches directly from the left coronary artery?

Marginal artery

Anterior interventricular artery (correct)

Right coronary artery

Posterior interventricular artery

What is the role of the cardiac veins in the circulatory system?

Supply blood to the aortic valve

Remove waste products from the myocardium (correct)

Pump deoxygenated blood back to the lungs

Deliver oxygenated blood to coronary arteries

During which phase of the cardiac cycle is blood delivered to the myocardium?

Diastole Signup and view all the answers

Which of the following describes systemic circulation?

Involves the left side of the heart and delivers oxygenated blood to the body Signup and view all the answers

What is the primary function of the heart valves?

To prevent backflow of blood Signup and view all the answers

How many atrioventricular (AV) valves are present in the heart?

Two Signup and view all the answers

Which of the following statements best describes the function of the chordae tendinae?

They prevent the valves from eversion. Signup and view all the answers

Where is the tricuspid valve best heard when listening to heart sounds?

Left lower sternal border Signup and view all the answers

What triggers the semilunar valves to open?

The force of blood from contracting ventricles Signup and view all the answers

Which valve prevents backflow of blood into the right ventricle?

Pulmonary valve Signup and view all the answers

Which valve is also known as the mitral valve?

Bicuspid valve Signup and view all the answers

How many cusps does the aortic valve have?

Three Signup and view all the answers

Which chamber of the heart receives oxygenated blood from the lungs?

Left atrium Signup and view all the answers

What separates the left atrium from the right atrium?

Interatrial septum Signup and view all the answers

Which part of the heart is primarily responsible for pumping oxygenated blood to the body?

Left ventricle Signup and view all the answers

What is the function of the atrioventricular valves?

Prevent backflow into the atria Signup and view all the answers

The apex of the heart is located in which intercostal space?

5th intercostal space Signup and view all the answers

Which statement is true regarding the fibrous skeleton of the heart?

It supports the heart valves Signup and view all the answers

What describes the coronary circulation?

It supplies blood to the heart muscle Signup and view all the answers

What type of blood flows through the right ventricle?

Deoxygenated blood Signup and view all the answers

Which veins drain directly into the right atrium?

Anterior cardiac veins Signup and view all the answers

What is the primary purpose of coronary angiography?

To examine the patency of coronary vessels Signup and view all the answers

Which component is part of the conduction system responsible for initiating electrical impulses in the heart?

Sinoatrial (SA) node Signup and view all the answers

What effect does sympathetic stimulation have on the heart?

Increases heart rate and force of contraction Signup and view all the answers

Which nerve is primarily responsible for parasympathetic regulation of the heart?

Vagus nerve Signup and view all the answers

What role do afferent fibres parallel to the vagus nerve play in cardiac activity?

They sense changes in blood oxygen, carbon dioxide, and pH levels. Signup and view all the answers

What is the primary function of the fibrous skeleton of the heart?

To maintain synchrony between atria and ventricles Signup and view all the answers

Which of the following statements is true regarding the cardiac plexus?

It connects the autonomic nervous system to the conduction system. Signup and view all the answers

What can occur as a result of cardiac ischemia?

Referred pain Signup and view all the answers

What happens to the foramen ovale at birth?

It closes to become the fossa ovalis. Signup and view all the answers

Which structure constricts to become the ligamentum arteriosum after birth?

Ductus arteriosus Signup and view all the answers

Which condition is associated with the aortic valve?

Aortic dissection Signup and view all the answers

What is a common complication of congenital heart defects?

Arrhythmias Signup and view all the answers

Which cardiac issue is related to the myocardium?

Heart failure Signup and view all the answers

What is the fate of the ductus venosus after birth?

It fibroses and becomes a fibrous structure. Signup and view all the answers

Which of the following is NOT a component of the clinical correlations listed?

Abdomen Signup and view all the answers

Which structure serves as a conduit for blood flow between the pulmonary trunk and the aorta in a fetus?

Ductus arteriosus Signup and view all the answers

Which condition is associated with the coronary arteries?

Coronary artery disease Signup and view all the answers

What occurs to the pulmonary trunk at birth?

It directs blood towards the lungs for oxygenation. Signup and view all the answers

Study Notes

Heart Anatomy

The heart is a cone-shaped, muscular organ that pumps blood through the body.
It is approximately the size of a fist, weighing around 300 grams and measuring 11cm long.
Located within the mediastinum, it is protected by the ribs and sternum.
The heart lies between ribs 2-5 to the left of the midline, with the apex (bottom) positioned in the 5th intercostal space at the midclavicular line.

Heart Chambers

The heart is divided into four chambers:
- Two atria (upper chambers)
- Two ventricles (lower chambers)
The atria and ventricles are separated by the interatrial septum (between atria) and the interventricular septum (between ventricles).

Heart Valves

Valves are essential for ensuring unidirectional blood flow within the heart.
There are four valves:
- Two atrioventricular (AV) valves:
  - Tricuspid valve (right AV valve): located between the right atrium and right ventricle; three cusps.
  - Bicuspid/mitral valve (left AV valve): located between the left atrium and left ventricle; two cusps
- Two semilunar (SL) valves:
  - Pulmonary valve: three cusps; located between the right ventricle and pulmonary trunk.
  - Aortic valve: three cusps; located between the left ventricle and aorta.

Atrioventricular (AV) Valves

Open when blood flows from the atria to the ventricles.
Close during ventricular contraction (systole).
Chordae tendinae, attached to papillary muscles, prevent the valves from everting (turning inside out) and ensure blood does not flow back into the atria.
The closing of AV valves (tricuspid and mitral) produces S1 ("Lub") heart sound.

Semilunar (SL) Valves

Open during ventricular contraction (systole) as blood is ejected from the ventricles.
Close during ventricular relaxation (diastole) to prevent blood from flowing back into the ventricles.
The closing of SL valves (pulmonic and aortic) produces the S2 ("Dub") heart sound.

Heart Circulation

Pulmonary Circulation (blue):
- Involves the right side of the heart and the lungs.
- Deoxygenated blood is pumped from the right ventricle to the lungs for oxygenation.
Systemic Circulation (red):
- Involves the left side of the heart and the rest of the body.
- Oxygenated blood is pumped from the left ventricle to the body's organs and tissues to deliver oxygen and nutrients.

Coronary Circulation

Supplies the heart muscle with oxygen and nutrients.
Consists of coronary arteries that deliver blood and cardiac veins that remove waste.

Coronary Arteries

Main Branches:
- Right Coronary Artery (RCA):
  - Marginal artery
  - Posterior interventricular artery
- Left Coronary Artery (LCA):
  - Anterior interventricular artery (LAD)
  - Circumflex artery

Cardiac Veins

Drain into the coronary sinus, which empties into the right atrium.
Anterior cardiac veins drain directly into the right atrium.

Fibrous Skeleton of the Heart

A meshwork of dense connective tissue.
Functions as an insulator for electrical impulses, preventing direct conduction from the atria to the ventricles.
Supports and anchors the heart valves.

Regulation of Cardiac Activity

Conduction system:
- Sinoatrial (SA) node (pacemaker): initiates electrical impulses.
- Atrioventricular (AV) node: delays impulse conduction.
- AV bundle (bundle of His): conducts impulses to the ventricles.
- Right and left bundle branches: conduct impulses to specific ventricular regions.
- Purkinje fibers: conduct impulses throughout the ventricular myocardium.
Autonomic nervous system (ANS):
- Sympathetic: increases heart rate, force of contraction, and dilates coronary vessels.
- Parasympathetic: decreases heart rate and force of contraction.

Foetal Circulation

Before birth, the circulatory system undergoes significant adjustments to adapt to the absence of respiratory function in the womb.
Key features of foetal circulation:
- Foramen ovale: an opening between the right and left atria, allowing blood to bypass the lungs.
- Ductus arteriosus: a vessel connecting the pulmonary trunk to the aorta, allowing blood to bypass the pulmonary circulation.
- Umbilical cord: supplies the fetus with oxygen and nutrients from the placenta, and removes waste products.

Changes at Birth

When the newborn takes its first breath, the lungs expand, increasing pulmonary blood flow.
The foramen ovale closes, preventing blood from bypassing the lungs.
The ductus arteriosus constricts and eventually becomes the ligamentum arteriosum.
The umbilical cord is tied and severed, leading to closure of the umbilical vessels.

Clinical Correlations

Valves: Mitral valve prolapse, Tricuspid valve stenosis, Pulmonary valve stenosis, Aortic valve stenosis
Myocardium: Heart failure, Myocarditis, Myocardial infarction, Hypertrophic cardiomyopathy, Dilated cardiomyopathy
Pericardium: Pericarditis, Pericardial effusion, Cardiac tamponade, Constrictive pericarditis
Conduction System: Arrhythmias, Heart block, Congenital conduction defects, Atrial fibrillation, Ventricular fibrillation
Coronary Arteries: Coronary artery disease (CAD), Myocardial infarction (MI), Angina, Coronary artery aneurysm
Aorta and Great Vessels: Aortic aneurysm, Aortic dissection, Coarctation of the aorta, Atherosclerosis
Pulmonary Arteries: Pulmonary embolism, Pulmonary hypertension
Pulmonary Veins: Pulmonary venous congestion, Pulmonary venous obstruction, Pulmonary hypertension
Chambers of the Heart (Atria and Ventricles): Atrial fibrillation, Atrial septal defect, Ventricular septal defect, Congestive heart failure (CHF)
Ventricular Septum: Ventricular septal defect (VSD), Myocardial infarction involving the septum, Hypertrophic cardiomyopathy
Veins (e.g., coronary veins): Coronary sinus thrombosis, Venous insufficiency, Varicose veins, Deep vein thrombosis (DVT)
Pericardial Cavity: Pericardial effusion, Cardiac tamponade
Coronary Circulation (Arteries and Veins): Coronary artery disease (CAD), Angina, Coronary vein thrombosis, Coronary artery bypass grafting (CABG)
Fibrous Skeleton of the Heart: Valve regurgitation, Valve stenosis, Heart block (due to electrical disruption)
Autonomic Nervous System (ANS) Influence on Heart: Tachycardia, Bradycardia, Vasovagal syncope, Autonomic dysfunction
Foetal Circulation: Patent ductus arteriosus (PDA), Patent foramen ovale (PFO), Congenital heart defects

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Description

Explore the intricate structure and function of the heart in this quiz. Learn about the chambers, valves, and overall anatomy of this vital organ. Perfect for students of biology or those interested in human physiology.