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Differences in ventricular muscle thickness

In this figure the left panel shows the muscles of the heart in the relaxed position, and the right panel shows the muscles of the heart in contracted position.
The myocardium in the left ventricle is significantly thicker than that of the right ventricle. Both ventricles pump the same amount of blood, but the left ventricle must generate a much greater pressure to overcome greater resistance in the systemic circuit. The ventricles are shown in both relaxed and contracting states. Note the differences in the relative size of the lumens, the region inside each ventricle where the blood is contained.

Internal structure of the heart

Recall that the heart’s contraction cycle follows a dual pattern of circulation—the pulmonary and systemic circuits—because of the pairs of chambers that pump blood into the circulation. In order to develop a more precise understanding of cardiac function, it is first necessary to explore the internal anatomical structures in more detail.

Septa of the heart

There are four openings that allow blood to move from the atria into the ventricles and from the ventricles into the pulmonary trunk and aorta. Located in each of these openings between the atria and ventricles is a valve    , a specialized structure that ensures one-way flow of blood. The valves between the atria and ventricles are known generically as atrioventricular (AV) valves . The valves at the openings that lead to the pulmonary trunk and aorta are known generically as semilunar valves    .

Internal structures of the heart

In this figure the top panel shows the image of the heart with the major parts labeled. The bottom left panel shows a photo of the heart with the surface layer peeled off. The images on the bottom right show detailed musculature inside the heart.
This anterior view of the heart shows the four chambers, the major vessels and their early branches, as well as the valves.

Right atrium

The right atrium serves as the receiving chamber for blood returning to the heart from the systemic circulation. The two major systemic veins, the superior and inferior venae cavae, and the large coronary vein called the coronary sinus that drains the heart myocardium empty into the right atrium. The superior vena cava drains blood from regions abover the diaphragm: the head, neck, upper limbs, and the thoracic region. It empties into the superior and posterior portions of the right atrium. The inferior vena cava drains blood from areas below the diaphragm: the lower limbs and abdominal and pelvic region of the body. It, too, empties into the posterior portion of the atria, but is below the opening of the superior vena cava. The majority of the internal heart structures discussed in this and subsequent sections are illustrated in the provided figure.

The atria receive venous blood on a nearly continuous basis, preventing venous flow from stopping while the ventricles are contracting. While most ventricular filling occurs while the atria are relaxed, they do demonstrate a contractile phase and actively pump blood into the ventricles just prior to ventricular contraction. The opening between the atrium and ventricle is guarded by the tricuspid valve.

Right ventricle

The right ventricle receives blood from the right atrium through the tricuspid valve. Each flap of the valve is attached to strong strands of connective tissue, the chordae tendineae    , literally “tendinous cords,” or sometimes more poetically referred to as “heart strings.” There are several chordae tendineae associated with each of the flaps. They are composed of approximately 80 percent collagenous fibers with the remainder consisting of elastic fibers and endothelium. They connect each of the flaps to a papillary muscle    .

Questions & Answers

explain why is it that old peoples as from the age of 60 usually have eye problems?
Kenn Reply
most old people suffere eye problems.because of short sight where individuals with this kind of problems see only near objects clearly but not distance objects, this is cause by elongated eyeball so light from distance is focus infront the retina so the image on the retina is blurred .
Munyah
plasma DNA cytoplasm Ribosome
Pearl Reply
cell, tissue,organ, organ systems,organism
Pearl Reply
cell is the build block of Life
Pearl
also a smallest unit of life
Frankline
sure..
Pearl
consistsof cytoplsm enclosed with in a membrane which contains many biomolecules such as proteins and nucleic acids
Frankline
differences in the effects of infection by HIV and influenza A virus on host genetic variability.
Yo Reply
i dont know
Ubah
hiv is direct contact of blood or body fluid and if not treated can break down the immune system faster and lead to acids with complications of pneumonia skin infections inflammation of the brain etc.while influenza A is a air borne virus which can cause the common cold pain fever and can be cured
Maureen
A.I.D.S
Maureen
suggest bioingormatics research article plz
peermehirali
what makes the heart to pumps blood?
Jamer Reply
sa node
Ubah
i do think its the nerve tranmission to the brain
Frankline
The contracting and relaxing of the atria and vertricles but the electrical system of the heart is what makes this possible.
keynia
yes which is called autorhymicity
Maureen
adrenoline action in brains
Frankline Reply
please describe the human heart brefly
Shah Reply
the size of the heart is like a fist. it has four chambers. the left and right upper atrium which push blood in the lower left and right ventricles which in turns pump blood to the lungs or the rest of the body.
Maureen
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Frankline
Maureen is correct ,
Davis
right
Kenn
right
Ubah
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horyaal
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horyaal
What is housing?
Baldwin Reply
is where located you
Ubah
Hi, my name is Syedul Mostafa from Bangladesh Refugees camp. I would like to study under your.
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what is Endocytosis
Alice Reply
Endocytosis is the process where by organism lives inside it host and feed on it
Aboagye
cell
Mostafa
Endocytosis is the process where by substances are taken in to the cell of an organism
Abena
the taking in of matter by a living cell by invagination of its membrane to form a vacuole.
Amber
Exocytosis... is the durable, energy-consuming process by which a cell directs the contents of secretory vesicles out of the cell membrane and into the extracellular space. Endocytosis is an energy-using process by which cells absorb molecules (such as proteins) by engulfing them.
Amber
There are three types of endocytosis: phagocytosis, pinocytosis, and receptor-mediated endocytosis. In phagocytosis or “cellular eating,” the cell's plasma membrane surrounds a macromolecule or even an entire cell from the extracellular environment and buds off to form a food vacuole or phagosome.
Amber
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Abena
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Alice Reply
what the full meaning of ADP
Alice
ATP as simply called is substance which provide energy during active transport
Aboagye
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Alice Reply
biology simply means the study of life
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Aboagye
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Kami Reply
heart disease
Ashley
heart disease
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kidney failure
John
heart failure
John
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Aboagye Reply
tanx wae
Aboagye
what is the name of the largest virus
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oohh
Rihan
this is in female body which have ovum which is without fertilization if ovum is fertilize then it is called egg
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Sanjay
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Sanjay
what is cell division
Kami
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what is the difference between DNA and RNA?
Jackson Reply

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Source:  OpenStax, Human biology. OpenStax CNX. Dec 01, 2015 Download for free at http://legacy.cnx.org/content/col11903/1.3
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