For other uses, see Vein (disambiguation).
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This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2012) |
| Vein |
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| The main veins in the human body |
| Latin |
vena |
| System |
Circulatory system |
In the circulatory system, veins (from the Latin vena) are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. Veins differ from arteries in structure and function; for example, arteries are more muscular than veins, veins are often closer to the skin and contain valves to help keep blood flowing toward the heart, while arteries carry blood away from the heart.
Contents
- 1 Anatomy
- 1.1 Notable veins and vein systems
- 1.2 Color
- 2 Function
- 3 Classification
- 4 Clinical significance
- 4.1 Phlebology
- 4.2 Venous diseases
- 4.2.1 Venous insufficiency
- 4.2.2 Deep vein thrombosis
- 4.2.3 Thrombophlebitis
- 5 See also
- 6 References
- 7 External links
- 7.1 Scientific publications
Anatomy[edit]
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Diagram showing vein structure and a valve.
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In general, veins function to return deoxygenated blood to the heart, and are essentially tubes that collapse when their lumens are not filled with blood. The thick outermost layer of a vein is made of connective tissue, called tunica adventitia or tunica externa. There is a middle layer of bands of smooth muscle called tunica media, which are, in general, thin, as veins do not function primarily in a contractile manner. The interior is lined with endothelial cells called tunica intima. The precise location of veins is much more variable from person to person than that of arteries.[1] Veins often display a lot of anatomical variation compared with arteries within a species and between species.
Notable veins and vein systems[edit]
The great saphenous vein is the most important superficial vein of the lower limb. First described by the Persian physician Avicenna, this vein derives its name from the word safina, meaning "hidden". This vein is "hidden" in its own fascial compartment in the thigh and exits the fascia only near the knee. Incompetence of this vein is an important cause of varicose veins of lower limbs.
The pulmonary veins carry relatively oxygenated blood from the lungs to the heart. The superior and inferior venae cavae carry relatively deoxygenated blood from the upper and lower systemic circulations, respectively.
A portal venous system is a series of veins or venules that directly connect two capillary beds. Examples of such systems include the hepatic portal vein and hypophyseal portal system
The Thebesian veins within the myocardium of the heart are valveless veins that drain directly into the chambers of the heart. The coronary veins all empty into the coronary sinus which empties into the right atrium.
The dural venous sinuses within the dura mater surrounding the brain receive blood from the brain and also are a point of entry of cerebrospinal fluid from arachnoid villi absorption. Blood eventually enters the internal jugular vein.
Color[edit]
Vein color is determined in large part by the color of venous blood, which is usually dark red as a result of its low oxygen content. Veins appear blue because the subcutaneous fat absorbs low-frequency light, permitting only the highly energetic blue wavelengths to penetrate through to the dark vein and reflect back to the viewer. A study found the color of blood vessels is determined by the following factors: the scattering and absorption characteristics of skin at different wavelengths, the oxygenation state of blood, which affects its absorption properties, the diameter and the depth of the vessels, and the visual perception process.[2]
Function[edit]
Veins serve to return blood from organs to the heart. Veins are also called "capacitance vessels" because most of the blood volume (60%) is contained within veins. In systemic circulation oxygenated blood is pumped by the left ventricle through the arteries to the muscles and organs of the body, where its nutrients and gases are exchanged at capillaries. After taking up cellular waste and carbon dioxide in capillaries, blood is channeled through vessels that converge with one another to form venules, which continue to converge and form the larger veins. The de-oxygenated blood is taken by veins to the right atrium of the heart, which transfers the blood to the right ventricle, where it is then pumped through the pulmonary arteries to the lungs. In pulmonary circulation the pulmonary veins return oxygenated blood from the lungs to the left atrium, which empties into the left ventricle, completing the cycle of blood circulation.
The return of blood to the heart is assisted by the action of the skeletal-muscle pump, and by the thoracic pump action of breathing during respiration. Standing or sitting for a prolonged period of time can cause low venous return from venous pooling (vascular) shock. Fainting can occur but usually baroreceptors within the aortic sinuses initiate a baroreflex such angiotensin II and norepinephrine stimulate vasoconstriction and heart rate increases to return blood flow. Neurogenic and hypovolaemic shock can also cause fainting. In these cases, the smooth muscles surrounding the veins become slack and the veins fill with the majority of the blood in the body, keeping blood away from the brain and causing unconsciousness. Jet pilots wear pressurized suits to help maintain their venous return and blood pressure.
The arteries are perceived as carrying oxygenated blood to the tissues, while veins carry deoxygenated blood back to the heart. This is true of the systemic circulation, by far the larger of the two circuits of blood in the body, which transports oxygen from the heart to the tissues of the body. However, in pulmonary circulation, the arteries carry deoxygenated blood from the heart to the lungs, and veins return blood from the lungs to the heart. The difference between veins and arteries is their direction of flow (out of the heart by arteries, returning to the heart for veins), not their oxygen content. In addition, deoxygenated blood that is carried from the tissues back to the heart for reoxygenation in systemic circulation still carries some oxygen, though it is considerably less than that carried by the systemic arteries or pulmonary veins.
Although most veins take blood back to the heart, there is an exception. Portal veins carry blood between capillary beds. For example, the hepatic portal vein takes blood from the capillary beds in the digestive tract and transports it to the capillary beds in the liver. The blood is then drained in the gastrointestinal tract and spleen, where it is taken up by the hepatic veins, and blood is taken back into the heart. Since this is an important function in mammals, damage to the hepatic portal vein can be dangerous. Blood clotting in the hepatic portal vein can cause portal hypertension, which results in a decrease of blood fluid to the liver.
Also transports proteins and other materials throughout the body.
Classification[edit]
Image of veins from William Harvey's
De Motu Cordis et Sanguinis, 1628
Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small.
- Superficial veins
- Superficial veins are those whose course is close to the surface of the body, and have no corresponding arteries.
- Deep veins
- Deep veins are deeper in the body and have corresponding arteries.
- Communicating veins
- Communicating veins (or perforator veins) are veins that directly connect superficial veins to deep veins.
- Pulmonary veins
- The pulmonary veins are a set of veins that deliver oxygenated blood from the lungs to the heart.
- Systemic veins
- Systemic veins drain the tissues of the body and deliver deoxygenated blood to the heart.
Clinical significance[edit]
Phlebology[edit]
Venous valves prevent reverse blood flow.
Phlebology is the medical specialty devoted to the diagnosis and treatment of venous disorders. A medical specialist in Phlebology is termed a Phlebologist. The American Medical Association added phlebology to their list of self-designated practice specialties in 2005. In 2007, the American Board of Phlebology (ABPh), now known as the American Board of Venous & Lymphatic Medicine (ABVLM), was established to improve the standards of phlebologists and the quality of their patient care by establishing a certification examination, as well as requiring maintenance of certification as a phlebologist. Although not currently a Member Board of the American Board of Medical Specialties (ABMS); the American Board of Venous & Lymphatic Medicine certification exam is based on ABMS standards. A related image is called a phlebography
Video of venous valve in action
The American College of Phlebology (ACP) is one of the largest medical societies in the world for physicians and allied health professionals working in the field of phlebology. The ACP has 2000 members and is dedicated to advancing vein care. The ACP encourages education and training to improve the standards of medical practitioners and the quality of patient care. The ACP supports phlebology research and the development of future research leaders through several generous grants: Research-In-Practice Grant ($24,000 for 12 months), Research Trainee Grant ($45,000 for 12 months), Junior Faculty Investigator Grant ($70,000 for 12 months), JOBST Research Award of the Advancement of Phlebology ($15,000 for 12 months), and the Walter P. deGroot, MD Clinical Phlebology Fellowship. The ACP is committed to promoting public education and their understanding of phlebology and the value of Phlebologists. This is accomplished through many avenues, including, but not limited to: the Healthy Veins Website (www.healthyveins.org), the Re-think Varicose Veins campaign (www.rethinkvaricoseveins.com), and the PBS special ‘Vein Health: Discoveries, New Technologies & Breakthroughs’.
The ACP is part of the UIP (International Union of Phlebology) and will host the XVII International Union of Phlebology World Meeting in Boston, Massachusetts from September 8-13, 2013 - bringing the meeting to the United States for the first time in its history. The equivalent body for countries in the Pacific is the Australasian College of Phlebology, active in Australia and New Zealand.
The American Venous Forum (AVF) The American Venous Forum (AVF) is a medical society for physicians and allied health professionals dedicated to improving the care of patients with venous and lymphatic disease. The majority of its members manage the entire spectrum of venous and lymphatic diseases – from varicose veins, to congenital abnormalities to deep vein thrombosis to chronic venous diseases. Founded in 1987, the AVF encourages research, clinical innovation, hands-on education, data collection and patient outreach.
Venous diseases[edit]
Venous insufficiency[edit]
Main article: Chronic venous insufficiency
Venous insufficiency is the most common disorder of the venous system, and is usually manifested as spider veins or varicose veins. Several varieties of treatments are used, depending on the patient's particular type and pattern of veins and on the physician's preferences. Treatment can include Endovenous Thermal Ablation using radiofrequency or laser energy, vein stripping, ambulatory phlebectomy, foam sclerotherapy, lasers, or compression.
Postphlebitic syndrome is venous insufficiency that develops following deep vein thrombosis.[3]
Deep vein thrombosis[edit]
Main article: Deep vein thrombosis
Deep-vein thrombosis is a condition in which a blood clot forms in a deep vein, which can lead to pulmonary embolism and chronic venous insufficiency.
Thrombophlebitis[edit]
Main article: Thrombophlebitis
Thrombophlebitis is an inflammatory condition of the veins related to blood clots.
See also[edit]
- Deep vein
- Deep vein thrombosis
- May-Thurner Syndrome
- Nutcracker Syndrome
- Peripheral vein
- Phlebologist
- Pulmonary circulation
- Superficial vein
- Thorasic Outlet Syndrome
- Varicose veins
References[edit]
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This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (January 2008) |
- ^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Alexandra Senckowski, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey: Prentice Hall. ISBN 0-13-981176-1.
- ^ Kienle, Alwin; Lilge, Lothar; Vitkin, I. Alex; Patterson, Michael S.; Wilson, Brian C.; Hibst, Raimund; Steiner, Rudolf (1 March 1996). "Why do veins appear blue? A new look at an old question". Applied Optics 35 (7): 1151. doi:10.1364/AO.35.001151. PMID 21085227.
- ^ Kahn SR (August 2006). "The post-thrombotic syndrome: progress and pitfalls". British Journal of Haematology 134 (4): 357–65. doi:10.1111/j.1365-2141.2006.06200.x. PMID 16822286.
External links[edit]
- Merck Manual article on veins
- American Venous Forum
- American College of Phlebology
- American Board of Phlebology
- American College of Phlebology Foundation
- Australasian College of Phlebology Information from the Australasian College of Phlebology Website
- In economics: Arterial and venous industries
- Animated Venous Access tutorials
Scientific publications[edit]
- Phlebology: The Journal of Venous Disease
- Phlebology: 1986-1999
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Human systems and organs
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TA 2–4:
MS |
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Skeletal system
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- Bone
- Carpus
- Collar bone (clavicle)
- Thigh bone (femur)
- Fibula
- Humerus
- Mandible
- Metacarpus
- Metatarsus
- Ossicles
- Patella
- Phalanges
- Radius
- Skull (cranium)
- Tarsus
- Tibia
- Ulna
- Rib
- Vertebra
- Pelvis
- Sternum
- Cartilage
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Joints
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- Fibrous joint
- Cartilaginous joint
- Synovial joint
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Muscular system
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TA 5–11:
splanchnic/
viscus |
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mostly
Thoracic
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mostly
Abdominopelvic
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Digestive system+
adnexa
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- Mouth
- upper GI
- Oropharynx
- Laryngopharynx
- Esophagus
- Stomach
- lower GI
- Small intestine
- Appendix
- Colon
- Rectum
- Anus
- accessory
- Liver
- Biliary tract
- Pancreas
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GU: Urinary system
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- Kidney
- Ureter
- Bladder
- Urethra
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GU: Reproductive system
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- Female
- Uterus
- Vagina
- Vulva
- Ovary
- Placenta
- Male
- Scrotum
- Penis
- Prostate
- Testicle
- Seminal vesicle
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Endocrine system
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- Pituitary
- Pineal
- Thyroid
- Parathyroid
- Adrenal
- Islets of Langerhans
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| TA 12–16 |
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Circulatory system
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Cardiovascular system
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- peripheral
- Artery
- Vein
- Lymphatic vessel
- Heart
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Lymphatic system
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Nervous system
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Integumentary system
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- Skin
- Subcutaneous tissue
- Breast
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Blood
(Non-TA) |
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General anatomy: systems and organs, regional anatomy, planes and lines, superficial axial anatomy, superficial anatomy of limbs
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Circulatory system: Arteries and veins (TA A12.0, TH H3.09.02, GA 6.543/GA 7.641)
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| Systemic circulation |
(Left heart) → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Vena cava → (Right heart)
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| Pulmonary circulation |
(Right heart) → Pulmonary arteries → (Lungs) → Pulmonary vein → (Left heart)
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| Blood vessels |
- Tunica intima (Endothelium, Internal elastic lamina)
- Tunica media
- Tunica externa
- Vasa vasorum
- Vasa nervorum
- Rete mirabile
- Circulatory anastomosis
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| Arteries |
- Nutrient artery
- Arteriole
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| Veins |
- Vena comitans
- Superficial vein
- Deep vein
- Emissary veins
- Venous plexus
- Venule
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| Lymphatic |
- Lymphatic vessel
- Lymph
- Lymph capillary
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anat (a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot
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noco/syva/cong/lyvd/tumr, sysi/epon, injr
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proc, drug (C2s+n/3/4/5/7/8/9)
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Veins (emissary, jugular and others) of head and neck (drainage patterns can vary) (TA A12.3.04–06, GA 7.644)
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| External jugular |
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Retromandibular
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maxillary (pterygoid plexus) · superficial temporal (anterior auricular)
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Direct
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posterior auricular
transverse cervical · suprascapular · anterior jugular (jugular venous arch)
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| Internal jugular |
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Diploic/brain
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Cerebral
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Superficial cerebral veins: superior · superficial middle · inferior · inferior anastomotic (Labbé) · superior anastomotic (Trolard)
Deep cerebral veins: great · internal (basal, deep middle, superior thalamostriate)
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Cerebellar
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superior · inferior
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Sinuses
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To COS
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superior sagittal · straight (inferior sagittal) · occipital
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To CS
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sphenoparietal · intercavernous
superior ophthalmic (ethmoidal, central retinal, nasofrontal, vorticose veins) · inferior ophthalmic
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To IJV
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sigmoid: transverse (petrosquamous) · superior petrosal
inferior petrosal (basilar plexus, internal auditory veins) · condylar
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Facial/common facial
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frontal · supraorbital · angular · superior labial · inferior labial · deep facial
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Direct
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lingual (dorsal lingual, deep lingual, sublingual) · pharyngeal · superior thyroid (superior laryngeal) · middle thyroid
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| Brachiocephalic |
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Vertebral
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occipital (occipital emissary) · suboccipital venous plexus
deep cervical
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Direct
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inferior thyroid (inferior laryngeal) · thymic
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anat (a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot
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noco/syva/cong/lyvd/tumr, sysi/epon, injr
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proc, drug (C2s+n/3/4/5/7/8/9)
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Veins of upper limbs (TA A12.3.08, GA 7.660)
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| General |
Subscapular · Axillary · Circumflex scapular
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| Superficial |
arm: Cephalic (Accessory cephalic) · Median cubital · Basilic · Median antebrachial
hand/forearm: Dorsal network (Intercapitular, Dorsal metacarpal) · Superficial palmar arch (Palmar digital)
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| Deep |
arm: Radial · Ulnar · Brachial
hand/forearm: Deep palmar arch (Palmar metacarpal)
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anat (a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot
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noco/syva/cong/lyvd/tumr, sysi/epon, injr
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proc, drug (C2s+n/3/4/5/7/8/9)
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Veins of the thorax and vertebral column (TA A12.3.01–04, 07, GA 7.664)
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| Thorax |
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Coronary
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Coronary sinus
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Great cardiac (Left marginal) · Posterior of the left ventricle · Oblique of the left atrium (Ligament of the left vena cava) · Middle cardiac
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Small cardiac vein
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Anterior cardiac (Right marginal)
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Smallest cardiac veins
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Right atrial veins · Right ventricular veins
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Pulmonary
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right inferior pulmonary vein · right superior pulmonary vein · left inferior pulmonary vein · left superior pulmonary vein
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SVC
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Brachiocephalic
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internal thoracic (anterior intercostal, superior epigastric, Kacheshmarova's vein (vena xiphia (vena africana))) · left superior intercostal · supreme · vertebral · subclavian (axillary: lateral thoracic, thoracoepigastric, dorsal scapular, external jugular) · pericardiacophrenic · internal jugular
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Azygos
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right superior intercostal · bronchial · intercostal/posterior intercostal 5-11 · accessory hemiazygos/hemiazygos · superior phrenic
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Striolae
|
striola luteola · striola aureola · striola rubella
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| Vertebral column |
vertebral venous plexuses (external, internal) · spinal (posterior, anterior) · basivertebral · intervertebral
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anat (a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot
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noco/syva/cong/lyvd/tumr, sysi/epon, injr
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proc, drug (C2s+n/3/4/5/7/8/9)
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Veins of the abdomen and pelvis (TA A12.3.09–10, 12, GA 7.672)
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| To azygos system |
ascending lumbar (subcostal)
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IVC
(Systemic) |
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To IVC or left renal vein
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inferior phrenic · hepatic (central veins of liver, liver sinusoid) · suprarenal · renal · gonadal (ovarian ♀/testicular ♂, pampiniform plexus ♂) · lumbar · common iliac
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Common iliac
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Unpaired
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median sacral vein
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Internal iliac
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posterior: iliolumbar · superior gluteal · lateral sacral
anterior: inferior gluteal · obturator · uterine ♀ (uterine plexus ♀) · vesical (vesical plexus, prostatic plexus ♂, deep of penis ♂/clitoris ♀, posterior scrotal ♂/labial ♀) · vaginal plexus/vein ♀ · middle rectal · internal pudendal (inferior rectal, bulb of penis ♂/vestibule ♀) · rectal plexus
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External iliac
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inferior epigastric · deep circumflex iliac vein
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Striolae
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striola caeruleola · striola viridicula · striola purpuraceola · striola roseola
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Portal vein
(Portal) |
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Splenic
|
short gastric · left gastroepiploic · pancreatic · inferior mesenteric (superior rectal, left colic)
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Superior mesenteric
|
right gastroepiploic · pancreaticoduodenal · jejunal · ileal · middle colic · right colic · ileocolic (appendicular)
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Direct
|
cystic · left gastric/esophageal · right gastric · paraumbilical
|
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anat (a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot
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noco/syva/cong/lyvd/tumr, sysi/epon, injr
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proc, drug (C2s+n/3/4/5/7/8/9)
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Veins of lower limbs (TA A12.3.11, GA 7.669)
|
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| thigh |
femoral · profunda femoris · popliteal
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| deep leg |
fibular · anterior tibial · posterior tibial
|
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| superficial leg |
small saphenous · great saphenous (external pudendal, superficial of penis ♂/clitoris ♀)
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|
| foot |
dorsal arch · dorsal metatarsal · dorsal digital · plantar arch · plantar metatarsal · common digital · plantar digital
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|
anat (a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot
|
noco/syva/cong/lyvd/tumr, sysi/epon, injr
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proc, drug (C2s+n/3/4/5/7/8/9)
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