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Overview of systemic veins

Systemic veins return blood to the right atrium. Since the blood has already passed through the systemic capillaries, it will be relatively low in oxygen concentration. In many cases, there will be veins draining organs and regions of the body with the same name as the arteries that supplied these regions and the two often parallel one another. This is often described as a “complementary” pattern. However, there is a great deal more variability in the venous circulation than normally occurs in the arteries. For the sake of brevity and clarity, this text will discuss only the most commonly encountered patterns. However, keep this variation in mind when you move from the classroom to clinical practice.

In both the neck and limb regions, there are often both superficial and deeper levels of veins. The deeper veins generally correspond to the complementary arteries. The superficial veins do not normally have direct arterial counterparts, but in addition to returning blood, they also make contributions to the maintenance of body temperature. When the ambient temperature is warm, more blood is diverted to the superficial veins where heat can be more easily dissipated to the environment. In colder weather, there is more constriction of the superficial veins and blood is diverted deeper where the body can retain more of the heat.

The “Voyage of Discovery” analogy and stick drawings mentioned earlier remain valid techniques for the study of systemic veins, but veins present a more difficult challenge because there are numerous anastomoses and multiple branches. It is like following a river with many tributaries and channels, several of which interconnect. Tracing blood flow through arteries follows the current in the direction of blood flow, so that we move from the heart through the large arteries and into the smaller arteries to the capillaries. From the capillaries, we move into the smallest veins and follow the direction of blood flow into larger veins and back to the heart. [link] outlines the path of the major systemic veins.

Visit this site for a brief online summary of the veins.

Major systemic veins of the body

This diagram shows the major veins in the human body.
The major systemic veins of the body are shown here in an anterior view.

The right atrium receives all of the systemic venous return. Most of the blood flows into either the superior vena cava or inferior vena cava. If you draw an imaginary line at the level of the diaphragm, systemic venous circulation from above that line will generally flow into the superior vena cava; this includes blood from the head, neck, chest, shoulders, and upper limbs. The exception to this is that most venous blood flow from the coronary veins flows directly into the coronary sinus and from there directly into the right atrium. Beneath the diaphragm, systemic venous flow enters the inferior vena cava, that is, blood from the abdominal and pelvic regions and the lower limbs.

The superior vena cava

The superior vena cava    drains most of the body superior to the diaphragm ( [link] ). On both the left and right sides, the subclavian vein    forms when the axillary vein passes through the body wall from the axillary region. It fuses with the external and internal jugular veins from the head and neck to form the brachiocephalic vein    . Each vertebral vein    also flows into the brachiocephalic vein close to this fusion. These veins arise from the base of the brain and the cervical region of the spinal cord, and flow largely through the intervertebral foramina in the cervical vertebrae. They are the counterparts of the vertebral arteries. Each internal thoracic vein    , also known as an internal mammary vein, drains the anterior surface of the chest wall and flows into the brachiocephalic vein.

Questions & Answers

why are cells small
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What are variations in physiology
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pls let's talk about d difference between mitosis and meiosis
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through remodeling and formation of new bones
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Monica
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HALLELUYAH
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HALLELUYAH
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join
Hajiahamdy
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which secrete hormones and other products direct into the blood
Aadi
Cell is basic, structural and functional unit of life
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The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life." Some organisms, such as bacteria, are unicellular, consisting of a single cell.
Br_
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Rachel
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HALLELUYAH
what is the basic function of the lymphatic system
HALLELUYAH
The other main function is that of defense in the immune system. Lymph is very similar to blood plasma: it contains lymphocytes. It also contains waste products and cellular debris together with bacteria and proteins. Associated organs composed of lymphoid tissue are the sites of lymphocyte producti
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the function of lymphatic system are 1fluid balance 2 lipid absorption and 3 defence
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destroyed microognism
Usman
lymphatic systems main function is to transport lymph
Colleen
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Aminiely
Which of the following accurately describe external respirations
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anatomy is the study of STRUCTURE of the body while physiology is the study of the function of the part of the body
Gborgbor
Anatomy deals with the structure and parts of the body while physiology is the function of the the body parts
Archie
not understanding what is a cell
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its the fundamental unit of life or its the primary step in which two or more cell combine to form a tissue .
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Is the smallest structural and functional unit of life
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Ellen
Hydroxyapatite, also called hydroxylapatite, is a naturally occurring mineral form of calcium apatite with the formula Ca₅(PO₄)₃, but it is usually written Ca₁₀(PO₄)₆(OH)₂ to denote that the crystal unit cell comprises two entities. Hydroxyapatite is the hydroxyl endmember of the complex apatite gro
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osteomalacia is where inorganic or mineral which is calcium and phosphorus are removed from a bone....this will make the bone become flexible n in children is called ricket
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it is a protective layer of brain
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it is a kind of non movable joint present between skull bones
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suture is an example of fibrous joint and is synatrosys(is not movable)
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a junction between the sclerites of an imsect's body
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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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