Welcome to the MedLibrary.org Wikipedia Supplement on Systemic circulation -- Please Click to Return to Front Page

Systemic circulation is the portion of the cardiovascular system which carries oxygenated blood away from the heart, to the body, and returns deoxygenated blood back to the heart. The term is contrasted with pulmonary circulation.^[1]

Contents 1 Course 1.1 Arteries 1.1.1 Capillaries 1.2 Venules 1.3 Veins 2 Advantage 3 References 4 See also

Course

In the systemic circulation, arteries bring oxygenated blood to the tissues. As blood circulates through the body, oxygen diffuses from the blood into cells surrounding the capillaries, and carbon dioxide diffuses into the blood from the capillary cells. Veins bring deoxygenated blood back to the heart.

Arteries

See also: Arterial tree

Oxygenated blood enters the systemic circulation when leaving the left ventricle, through the aortic semi-lunar valve. The first part of the systemic circulation is the artery aorta, a massive and thick-walled artery. The aorta arches and gives off major arteries to the upper body before piercing the diaphragm in order to supply the lower parts of the body with its various branches.

Capillaries

Blood passes from arteries to capillaries, which are the thinnest and most numerous of the blood vessels. These capillaries help to join tissue with arterioles for transportation of nutrition to the cells, which absorb oxygen and nutrients in the blood. Peripheral tissues do not fully deoxygenate the blood, so venous blood does have oxygen, but in a lower concentration than in arterial blood. In addition, carbon dioxide and wastes are added.

Venules

The deoxygenated blood is then collected by venules, from where it flows first into veins, and then into the inferior and superior venae cavae, which return it to the right heart, completing the systemic cycle. The blood is then re-oxygenated through the pulmonary circulation before returning again to the systemic circulation.

Veins

The relatively deoxygenated blood collects in the venous system which coalesces into two major veins: the superior vena cava (roughly speaking from areas above the heart) and the inferior vena cava (roughly speaking from areas below the heart). These two great vessels exit the systemic circulation by emptying into the right atrium of the heart. The coronary sinus empties the heart's veins themselves into the right atrium.

Advantage

Because the systemic circulation is powered by the left ventricle (which is very muscular), one advantage of this form of circulation - as opposed to open circulation, or the gill system that fish use to breathe - is that there is simultaneous high-pressure oxygenated blood delivered to all parts of the body.

References

1. ^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, 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. 

See also

• Pulmonary circulation
• Double circulatory system

v • d • e Cardiovascular system Systemic circulation Heart  → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Vena cava → Heart Pulmonary circulation Heart → Pulmonary arteries → Lungs → Pulmonary vein → Heart Blood vessels Endothelium - Tunica intima - Tunica media - Tunica externa

v • d • e List of arteries of head and neck CC/EC sup. thyroid superior laryngeal – sternocleidomastoid branch – infrahyoid branch – cricothyroid branch – glandular branches asc. pharyngeal posterior meningeal – pharyngeal branches – inferior tympanic lingual suprahyoid – dorsal lingual – deep lingual – sublingual facial cervical branches (ascending palatine, tonsillar, submental, glandular) – facial branches (inferior labial, superior labial / nasal septum, lateral nasal, angular) occipital sternocleidomastoid – meningeal – occipital – auricular – descending post. auricular stylomastoid – stapedial – auricular – occipital sup. temporal transverse facial – middle temporal (zygomatico-orbital) – anterior auricular – frontal – parietal maxillary 1st part / mandibular: anterior tympanic – deep auricular – middle meningeal (superior tympanic, petrosal) – accessory meningeal – inferior alveolar (mental, mylohyoid) 2nd part / pterygoid: to muscles of mastication (deep temporal, pterygoid, masseteric) – buccal 3rd part / pterygopalatine: posterior superior alveolar – infraorbital (anterior superior alveolar) – descending palatine (greater palatine, lesser palatine) – artery of the pterygoid canal – sphenopalatine (posterior septal branches, posterior lateral nasal) CC/IC cervical carotid sinus petrous Vidian – caroticotympanic cavernous/ ophthalmic orbital group: posterior ethmoidal – anterior ethmoidal (anterior septal, anterior lateral nasal, anterior meningeal) – lacrimal (lateral palpebral) – medial palpebral – terminal (supraorbital, supratrochlear, dorsal nasal) ocular group: central retinal – ciliary (short posterior, long posterior, anterior) – hypophysial (superior, inferior) cerebral/Willis ACA (anterior communicating) – MCA (anterolateral central, lenticulostriate) – posterior communicating – anterior choroidal SC vertebral artery meningeal – spinal (posterior, anterior) – cerebellar (PICA) basilar: pontine – labyrinthine – cerebellar (AICA, SCA) – cerebral (PCA) thyrocervical trunk inferior thyroid: inferior laryngeal – tracheal – esophageal – ascending cervical – pharyngeal – glandular branches transverse cervical: superficial branch – deep branch / dorsal scapular suprascapular: acromial branch costocervical trunk deep cervical

v • d • e List of arteries of upper limbs Axillary scapular anastomosis – 1st part superior thoracic – 2nd part thoracoacromial (deltoid branch) – lateral thoracic – 3rd part subscapular (circumflex scapular, thoracodorsal) – anterior humeral circumflex – posterior humeral circumflex Brachial profunda brachii (radial collateral, medial collateral) – ulnar collateral (superior, inferior) Radial forearm: radial recurrent wrist/carpus: dorsal carpal branch – palmar carpal branch hand: superficial palmar branch – princeps pollicis (radial of index finger) Ulnar forearm: ulnar recurrent (anterior, posterior) – common interosseous (anterior, posterior, recurrent) wrist/carpus: dorsal carpal branch – palmar carpal branch hand: deep palmar branch Arches dorsal carpal arch: dorsal metacarpal (dorsal digital) palmar carpal arch superficial palmar arch: common palmar digital (proper palmar digital) deep palmar arch: palmar metacarpal

v • d • e List of arteries of torso – chest Pulmonary/ coronary right coronary: SA nodal – AV nodal – atrial – right marginal – posterior interventricular left coronary: anterior interventricular – left circumflex (left marginal) Ascending aorta aortic arch – brachiocephalic (thyreoidea ima) – common carotid Subclavian internal thoracic: anterior intercostal – thymic – pericardiacophrenic – terminal (musculophrenic, superior epigastric) costocervical trunk: highest intercostal (posterior intercostal 1–2) – deep cervical Descending/ thoracic aorta visceral: bronchial – esophageal – mediastinal parietal: posterior intercostal 3–11 – subcostal – superior phrenic

v • d • e List of arteries of torso – abdomen AA: Anterior celiac left gastric: esophageal branches splenic: pancreatic branches (greater, dorsal) – short gastric – left gastro-omental common hepatic: proper hepatic (cystic), right gastric, gastroduodenal (right gastro-omental, superior pancreaticoduodenal, supraduodenal) SMA inferior pancreaticoduodenal – intestinal (jejunal, ileal, arcades, vasa recta)  – ileocolic (colic, anterior cecal, posterior cecal, ileal branch, appendicular)  – right colic – middle colic IMA left colic – sigmoid – superior rectal – marginal AA: Posterior visceral: middle suprarenal – renal (inferior suprarenal, ureteral) – gonadal (testicular ♂ / ovarian ♀) parietal: inferior phrenic (superior suprarenal) – lumbar – median sacral terminal: common iliac (IIA, EIA) IIA: Anterior umbilical (superior vesical, to ductus deferens) – middle rectal – obturator (anterior branch, posterior branch) – inferior gluteal (accompanying of ischiadic nerve, crucial anastomosis) uterine ♀ (helicine, vaginal of uterine, ovarian of uterine, tubal of uterine) – vaginal ♀ / inferior vesical ♂ internal pudendal: inferior rectal – perineal (urethral) – posterior scrotal ♂ / labial ♀ – bulb of penis ♂ / vestibule ♀ – deep artery of the penis ♂ (helicine) / clitoris ♀ – dorsal of the penis ♂ / clitoris ♀ IIA: Posterior iliolumbar (lumbar, iliac) – lateral sacral – superior gluteal EIA inferior epigastric (cremasteric, round ligament) – deep circumflex iliac – femoral

v • d • e List of arteries of lower limbs EI: Femoral superficial epigastric – superficial iliac circumflex external pudendal: superficial – deep (anterior scrotal) profunda femoris: lateral circumflex femoral (descending, transverse, ascending) – medial circumflex femoral (ascending, superficial, deep, acetabular) – perforating descending genicular (saphenous branch, articular branches) Popliteal sural genicular: superior genicular (medial, lateral) – middle genicular – inferior genicular (medial, lateral) Anterior tibial tibial recurrent (posterior, anterior) anterior malleolar (medial, lateral) dorsalis pedis: tarsal (medial, lateral) Posterior tibial circumflex fibular – fibular medial plantar – lateral plantar Arches arcuate: dorsal metatarsal / first dorsal metatarsal – deep plantar – dorsal digital arteries plantar arch: plantar metatarsal – common plantar digital – proper plantar digital

Wikipedia content modification information:

• This page was last modified on 7 August 2008, at 14:28.

Wikipedia Authorship and Review

Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.

Wikipedia Usage Guidelines

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Systemic circulation".

The URL for this specific entry is:

• http://medlibrary.org/medwiki/Systemic_circulation

All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.