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Art connection

Illustration A shows the parts of the heart. Blood enters the right atrium through an upper, superior vena cava and a lower, inferior vena cava. From the right atrium, blood flows through the funnel-shaped tricuspid valve into the right ventricle. Blood then travels up and through the pulmonary valve into the pulmonary artery. Blood re-enters the heart through the pulmonary veins, and travels down from the left atrium, through the mitral valve, into the right ventricle. Blood then travels up through the aortic valve, into the aorta. The tricuspid and mitral valves are atrioventricular and funnel-shaped. The pulmonary and aortic valves are semilunar and slightly curved. An inset shows a cross section of the heart. The myocardium is the thick muscle layer. The inside of the heart is protected by the endocardium, and the outside is protected by the pericardium. Illustration B shows the outside of the heart. Coronary arteries and coronary veins run from the top down along the right and left sides.
(a) The heart is primarily made of a thick muscle layer, called the myocardium, surrounded by membranes. One-way valves separate the four chambers. (b) Blood vessels of the coronary system, including the coronary arteries and veins, keep the heart musculature oxygenated.

Which of the following statements about the heart is false?

  1. The mitral valve separates the left ventricle from the left atrium.
  2. Blood travels through the bicuspid valve to the left atrium.
  3. Both the aortic and the pulmonary valves are semilunar valves.
  4. The mitral valve is an atrioventricular valve.

The heart is composed of three layers; the epicardium, the myocardium, and the endocardium, illustrated in [link] . The inner wall of the heart has a lining called the endocardium    . The myocardium    consists of the heart muscle cells that make up the middle layer and the bulk of the heart wall. The outer layer of cells is called the epicardium    , of which the second layer is a membranous layered structure called the pericardium    that surrounds and protects the heart; it allows enough room for vigorous pumping but also keeps the heart in place to reduce friction between the heart and other structures.

The heart has its own blood vessels that supply the heart muscle with blood. The coronary arteries branch from the aorta and surround the outer surface of the heart like a crown. They diverge into capillaries where the heart muscle is supplied with oxygen before converging again into the coronary veins to take the deoxygenated blood back to the right atrium where the blood will be re-oxygenated through the pulmonary circuit. The heart muscle will die without a steady supply of blood. Atherosclerosis is the blockage of an artery by the buildup of fatty plaques. Because of the size (narrow) of the coronary arteries and their function in serving the heart itself, atherosclerosis can be deadly in these arteries. The slowdown of blood flow and subsequent oxygen deprivation that results from atherosclerosis causes severe pain, known as angina    , and complete blockage of the arteries will cause myocardial infarction    : the death of cardiac muscle tissue, commonly known as a heart attack.

The cardiac cycle

The main purpose of the heart is to pump blood through the body; it does so in a repeating sequence called the cardiac cycle. The cardiac cycle    is the coordination of the filling and emptying of the heart of blood by electrical signals that cause the heart muscles to contract and relax. The human heart beats over 100,000 times per day. In each cardiac cycle, the heart contracts ( systole    ), pushing out the blood and pumping it through the body; this is followed by a relaxation phase ( diastole    ), where the heart fills with blood, as illustrated in [link] . The atria contract at the same time, forcing blood through the atrioventricular valves into the ventricles. Closing of the atrioventricular valves produces a monosyllabic “lup” sound. Following a brief delay, the ventricles contract at the same time forcing blood through the semilunar valves into the aorta and the artery transporting blood to the lungs (via the pulmonary artery). Closing of the semilunar valves produces a monosyllabic “dup” sound.

Questions & Answers

What is a ploidy level
Francis Reply
what do you guys understand about evolution?
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Fahamia
is a study of
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Sarah
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Rahim
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Mohammed
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Safuna
hi
Kaniki
why are diagrams not available
Evans Reply
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Julia Reply
describe the breathing mechanism in the body fish.
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what is genetics.
Jackson
the study of hereditary
Julia
state the importance of biodiversity of organisms in an area?
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Biology is the study of living things.
Patrick
what are some of the branches of biology?
Jackson
anatomy,genetics,parasitology
Evans
what is meosis
Mabatho Reply
did you mean meiosis? meiosis this is the type of cell division where one diploid parent cell produces two daughter cells that are haploid and genetically different from the parent cell.
Patrick
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Mabatho
I'm struggling to understand genetics
Mabatho
Am also struggling as well
Patrick
nothing comes on a silver platter, you need to put effort in everything you are doing not forgetting God. study as if there is no tomorrow. "Suffer now and enjoy the future"
Patrick
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Odhiambo
Glory to God
Patrick
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Mabatho
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what's a nervous system
tessy Reply
what's the human brain
tessy
the structure of paramecium
Charity Reply
yes
Sarah
Ho
Nevers
what is endocytosis
Stephen Reply
what is the meaning of adrenocorticotropic
Abigail Reply
adrenocorticotropic is stimulating or acting on the adrenal cortex.
Belinda
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Abigail
What is science of biology
Thando Reply
The study 📓 of leaving things
John
how does a parasite benefit from its mode of living?
Abuk Reply
why are the images n diagrams unable to be seen?
Abuk
where are the illustrations
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a parasite gets protection, food, shelter
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human being
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what is Alimentary canal?
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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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