Question

Concisely describes the role of heart anatomy and its effect on the ability of the heart to pump

Answer 1

Ans) Anatomy of heart:

• The heart is a four-chambered muscular organ containing an involuntary conduction system that initiates rhythmic contractions to pump blood throughout the body.
• The heart has its own blood supply and is controlled by self-regulating nerve bundles called nodes.
• The SA and AV nodes send impulses through the Purkinje fibers that cause muscle contractions to the heart.
• The heart is composed of three layers: the epicardium (outer layer) which prevents excess expansion or movement of the heart, the myocardium (middle layer) which initiates contractions driving the cardiac cycle, and the endocardium (inner layer) that lines the cavities and valves.
• The heart contains two upper chambers called atria and two lower chambers called ventricles. The left and right sides of the heart are separated by the septum.
• Valves prevent the backflow of blood and separate the atria from the ventricle and the ventricle from the pulmonary artery or aorta.

• heart: A fist-sized muscular organ in the chest that pumps blood through the body using involuntary contractions of cardiac muscle.
• ventricle: One of two lower chambers of the heart that receives blood from the atria and pumps it out into pulmonary or systemic circulation, depending on side.
• myocardium: The middle of the three layers forming the wall of the heart, containing cardiac muscle tissue. Innervated by the Purkinje fibers.

Functioning of heart:

Blood vessels

Blood is pumped around the body through a network of blood vessels:

• arteries - they carry oxygen-rich blood from your heart to all parts of your body, getting smaller as they get further away from the heart
• capillaries - they connect the smallest arteries to the smallest veins, and help exchange water, oxygen, carbon dioxide and other nutrients and waste substances between the blood and the tissues around them
• veins - they carry blood, lacking in oxygen, back towards your heart, and get bigger as they get nearer your heart

- Blood vessels are able to widen or narrow depending on how much blood each part of your body requires. This action is partly controlled by hormones.

Valves - heart has four valves. They act like gates, keeping the blood moving in the right direction:

• aortic valve - on the left side
• mitral valve - on the left side
• pulmonary valve - on the right side
• tricuspid valve - on the right side

Electrical system - Heart to keep pumping regularly, it needs electrical signals which are sent to the heart muscle telling it when to contract and relax.

The electrical signal starts in the right atrium where your heart’s natural pacemaker - the sino–atrial node - is situated. This signal crosses the atria, making them contract. Blood is pumped through the valves into the ventricles.

Where the atria meet the ventricles, there is an area of special cells - called the atrio-ventricular node - which pass the electrical signals throughout your heart muscle by a system of electrical pathways, known as the conducting system.

The muscles of the ventricles then contract, and blood is pumped through the pulmonary and aortic valves into the main arteries.

The heart’s natural ‘pacemaker’ - the sino-atrial node - produces another electrical signal, and the cycle starts again.

• "Ejection" refers to the amount of blood that is pumped out of the heart's main pumping chamber, the left ventricle, during each heartbeat.

• "Fraction" refers to the fact that, even in a healthy heart, some blood always remains within this chamber after each heartbeat.

• An EF is a percentage of blood that is pumped out of the heart during each beat.

• EF indicates the heart is pumping well and able to deliver an adequate supply of blood to the body and brain.