Explain how the mammalian heart is adapted to performing its functions

The heart is made of muscles that contract and relax synchronously without requiring nervous stimulation

Nerve supply however, determine contraction strength and frequency

The heart is divided into four chambers

The right atrium is connected to the right auricle. It receives blood from the whole body.

The blood is pumped from the left atrium to the right ventricle

To avoid flow back into the right atrium, a valve is present between the two chambers

the tricuspid valve

The right ventricle pumps blood to the lungs

This is facilitated by the presence of pulmonary artery

A valve is also present to avoid blood flowing back from the pulmonary artery to the right ventricle

Blood from the lungs enters the heart through the pulmonary vein into the left atrium.

When the left atrium contracts, blood flows into the left ventricle

Blood will not flow back into the left atrium because of the presence of bicuspid valve(mitral)

The left ventricle is connected with the aorta and when it contracts, blood flows into the aorta for distribution into the whole body

The heart muscle surrounding the left ventricle is thicker than that surrounding the right ventricle to be able to generate enough pressure to push blood to the whole body

A pace-maker is present in the heart muscle to initiate and synchronise contractions.

For the heart muscle to be well nourished and be provided with enough oxygen and carbon IV oxide removal, it is supplied with blood by the coronary arteries and drained by the coronary veins

OR

- Has cardiac muscles that are myogenic; they are able to contract and relax rhythmically without fatigue.
- Has a coronary artery that supplies blood rich in oxygen and nutrients to the heart.
- Has a coronary vein that removes waste products rich in carbon dioxide and nitrogenous wastes from the heart muscles.
- Has Sino Atrial Node that acts as a pacemaker regulating rate of beating and excitation of the heart.
- Has Purkinje tissues that relay on waves from Arterio ventricular node to ventricular myocardium.
- Has Arterio ventricular Node that delays polarization wave from Sino Atrial Node to ensure auricles empties completely before the ventricles contract.
- Has ventricles that has thicker walls thus more muscular than auricles generating higher pressure to pump blood over long distances.
- Has valve tendons that acts as strands of connectivity tissue to prevent them from turning inside out when ventricle contracts.
- Has valves that prevents backflow of blood when auricles contracts.
- Has symphathetic nerves that speeds up the rate of heartbeat.
- Has vagous nerves that lowers down the rate of heartbeat.

OR

Has coronary arteries; which provides the heart muscle with oxygen and nutrients.
Has four chambers;for double circulation.
The atria have thin walls;as less force is needed to pump blood into ventricles.
The ventricles are thick walled;to pump blood to lungs and the rest if the body.
The left ventricle has thicker wall to create more pressure because it pumps blood for longer distances round the body;while the right ventricle pumps blood to the lungs close to heart.
The right and left Chambers are separated by a septum;the blood on the right side and left side do not mix.
Between atria and ventricles are atrio-ventricular valves made of thin,tough flaps of tissue;which prevents backflow of blood into atria;(bicuspid on left side,tricuspid on the right side).
The valves are held in place by tedinous chords;to hold them in place prevent tucking in.
Vena cava;brings in deoxygenated blood into right atrium.
Pulmonary vein; brings oxygenated blood into left atrium.
Pulmonary artery; takes blood to lungs for oxygenation.
Aorta; takes oxygenated blood to the rest of the body.
Pulmonary artery and aorta have semi-lunar valve;which prevent backflow into the heart.
The cardiac muscle is myogenic;it continues to pump blood without getting fatigued.
Has sino atrio-node/pacemaker; which initiates the wave of contraction;the rate of heartbeat is controlled by branches if sympathetic and parasympathetic nervous system.

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Mohaissack answered the question on October 4, 2017 at 14:20