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VESSELS general overview. tunica intima subedothelial layer of connective tissue membrana elastica interna tunica media membrana elastica externa tunica.

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Presentation on theme: "VESSELS general overview. tunica intima subedothelial layer of connective tissue membrana elastica interna tunica media membrana elastica externa tunica."— Presentation transcript:

1 VESSELS general overview

2 tunica intima subedothelial layer of connective tissue membrana elastica interna tunica media membrana elastica externa tunica adventitia = tunica externa GENERAL STRUCTURE OF VASCULAR WALL

3 General structure of vascular wall tunica intima tunica media tunica adventitia (externa)

4 Tunica intima endothelial cells (endotheliocyti) –simple flat/squamous epithelium –on basal lamina subendothelial layer (stratum subendotheliale) –loose connective tissue –some smooth muscle cells lamina elastica interna –elastin

5 Endothelial cells (Endotheliocyti) mesenchymal origin zonulae occludentes, desmosomes, nexuses intermediate filaments, microfilaments (contraction) corpora multitubularia (Weibel-Palade‘s bodies) f. VIII – vWF, P-selectin receptors: adrenergic, histaminic, ADH synthesis of vasoactive substances: NO, PG

6 Tunica media smooth muscle cells –spiral arrangement elastic a collagen fibers (type III) lamina elastica externa –only in thicker arteries

7 Tunica adventitia (externa) fibroblasts collagen fibers (type I) elastic fibers vasa vasorum nervi vasorum

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9 Vessel types arteries (arteriae) - aer + térein –muscular x elastic x mixed –microcirculation: small arteries – less than 1 mm –arterioles (arteriolae) less than 100 μm several layers of smooth muscle cells principal source of peripheral resistance !!! –metarterioly one smooth muscle cell layer, precapillary sphincter capillaries (vasa capillaria) –no nerve fibers –endotheliocyte + pericyte (Rouget‘ s cell) –caliber ± 7 μm

10 Vessel types veins (venae) –few muscle cells, more valvules –venules (venulae) capacity part of circulation (70% of blood) lymph vessels (vasa lymphatica) –lymph capillaries (vasa lymphocapillaria) originate as cul-de-sac –lymphatic trunks and ducts (trunci et ductus lymphatici) collectors in limbs valvules

11 Elastic arteries Elastic arteries aorta, truncus pulmonalis, a. subclavia, axillaris, iliaca, femoralis, thoracica int.

12 Elastic artery (Arteria elastotypica) Tunica intima –lamina elastica interna – incoherent Tunica media –elastic membranes with fenestrations – elastin –smooth muscle cells –lamina elastica externa Tunica adventitia (externa) –frequent vasa vasorum supply outer 2/3 of wall

13 Elastic artery (van Gieson + elastin)

14 Elastic artery (elastin)

15 Muscular artery (arteria musculotypica) Tunica intima –thin –lamina elastica interna – obvious Tunica media –circular smooth muscle cell layer (up to 40 layerss) each cell is covered with basal lamina – communication synthesis of extracellular matrix –lamina elastica externa – several elastic membranes Tunica externa –nerve bundles – contraction

16 Muscular artery Muscular artery (HE) (van Gieson + elastin)

17 Arterioles = Arteriolae Arterioles = Arteriolae caliber < 0.5 mm Tunica intima –Weibel-Palade‘ s bodies within endothelail cells (not in capillaries!) –lamina elastica int. – absent in smallest arterioles Tunica media –1-3 layers of smooth muscle cells –lamina elastica ext. – absent Tunica adventitia (externa) – very thin principal source of peripheral resistance

18 Arteriola Arteriola (HE)

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20 Sensory structures in arteries Glomera supracardiaca (aortica) – sup., medium, inf. - baroreceptors Sinus caroticus - baroreceptor –thicker, richly innervated tunica adventitia –thinner tunica media Glomus caroticum - chemoreceptors –oval structures mm glomus cells – large nucleus, vesicles with catecholamines shield cells – cover neural endings as glia

21 Capillaries (Vasa capillaria) microvascular part of circulation –vas capillare arteriale, intemredium, venosum –site of gas and nutrients exchange capillary –caliber 7-9 μm –length 1 mm (50 mm in renal glomerulus) –total length approximately km –formed by endothelial cells on basal lamina

22 Capillaries – wall structures Endothelial cell (Endothelicytus) Basal lamina (Lamina basalis) Pericyte (Pericytus; Rouget‘s cells) –mesenchymal cells with long processes –stem, supporting and transporting cell –proper lamina basalis –contractile proteins (replaces tunica media)

23 Capillary bed (HE)

24 Capillary types somatic capillaries –muscle, conncetive tissue, exocrinne glands (pinocytar vesicle in the wall), nervous tissue (no vesicles) fenestrated (visceral) capillaries with diaphragms –fenestrations nm (quick metabolic exchange) –kidneys, gut, endocrinne glands fenestrated capillaries without diaphragms –glomeruli in kidney sinusoids –caliber μm, often without lamina basalis –hematopoetic organs – liver, spleen, bone marrow, dental pulp glomus, glomi n. (vessel glomerule) – ball of fingers, nailbeds, auricle, penis / clitoris, uterus

25 Capillaries - function permeability –exchanger vessels (diffusion, pores, fenestration, vesicles) metabolic function –activation of angiotensin I  angiotensin II (lungs) –inactivation of bradykinin, serotonin, prostaglandins –lipolysis antithrombotic function –inhibition of tissue thromboplastin

26 Somatic capillary Somatic capillary (EG)

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28 Fenestrated capillary Fenestrated capillary (EG)

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30 Other structures of vascular wall vasa vasorum vasa nervorum nervi vasorum

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32 Other peculiar vascular structures vas anastomoticum (anastomosis) vas collaterale (collateral) rete mirabile = portal system –2 capillary beds series-connected anastomosis arteriovenosa (arteriolovenularis) –endothel bulges of intimal cushions with myoepitheloid cells simple (skin, lungs, kidneys) composed (glomus coccygeum)

33 Vessel network arrangement terminal (retina, spleen, kidney) functionally terminal (heart, brain) anastomotic angiogenesis – hypoxia is the strongest factor !

34 Clinical relevance aneurysma atherosclerosis (athere + skleros) necrosis, infarctus air embolism in large cervical veins varices

35 Blood distribution in organs heart (coronary arteries) 5% brain 15% muscles 15% viscera 35% kidneys 20% skin, skeleton 10% according to Stingl

36 Development of arterial system

37 Developmental arteries Saccus aorticus (aortal sac) Aa. arcuum pharyngeorum (pharyngeal arch arteries; „aortal arches“) –5 pairs develop and change successively Aorta dorsalis (original 2 merge into 1) –a.a segmentales ventrales (  a. omphalomesenterica, unpaired branches from AA) –truncus umbilicalis (  a. iliaca communis + int.) –a. umbilicalis –aa. segmentales laterales (  paired branches from AA) –aa. intersegmentales dorsolaterales (  branches from a. subclavia) –a. sacralis mediana

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39 Day 20-22

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41 Pharyngeal arch arteries derivates 1st pair – arteria maxillaris + carotis externa 2nd pair – arteria stapedia 3rd pair – central – arteria carotis communis – peripheral – arteria carotis interna

42 Pharyngeal arch arteries derivates 4th pair –left – part of the arcus aortae –right – a. subclavia dx. peripheral part of a. subclavia dx. is derived from aorta dorsalis dextra –a. subclavia sin. is NOT derived from the 4th aortic arch but from 7th intersegmental artery

43 Pharyngeal arch arteries derivates 5th – Ø 6th pair –left central left pulmonary artery peripheral ductus arteriosus (Botali) –right central right pulmonary artery peripheral Ø

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45 Arteriae omphalomesentericae (vitellinae) number of paired arteries supply yolk sac develop in vascular supply of gut → truncus coeliacus, arteria mesenterica superior et inferior

46 Arteriae umbilicales paired branches –central: truncus umbilicalis from aorta dorsalis –peripheral: within mass of diverticulum allantoicum to placenta (originally to allantois) in embryonic (connective) stalk or later in umbilical cord persist as arteriae iliacae internae and vesicales superiores –central: pars patens) –peripheral: ligamentum umbilicale mediale = pars occlusa

47 Malformation of arteries Ductus arteriosus patens Coarctatio aortae Arcus aortae duplex Arcus aortae dexter Arteria lusoria –abnormal origin of the right subclavian artery – obliteration of right aortic arch – origin of 7 th segmental artery

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51 Malformation of arteries course changes clinically relevant: –a. radialis a. brachioradialis (14%) –a. ulnaris a. brachioulnaris superficialis (3%)

52 Development of venous system

53 Developmental veins vv. somaticae v. cardinalis communis = ductus Cuvieri v. precardinalis (  v. jugularis int.+ ext.) v. postcardinalis (  v. azygos + hemiazygos) anastomosis subcardinalis –vv. subcardinales vv. intersegmentales – v. marginalis membri + v. axialis m.s./m.i.(  vv. subclaviae + superficial and deep limb veins) vv. viscerales vv. omphalomesentericae (vitellinae) v. umbilicalis (originally 2, right one disappears) v. pulmonalis communis

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55 Vena cava inferior v. omphalomesenterica intraembryonica  pars hepatica VCI anastomosis subcardinalis + v. subcardinalis dx.  pars subcardinalis VCI developmental anomalies 1-2% –infrarenal duplication

56 Vena portae vv. omphalomesentericae intraembryonicae vv. afferentes hepatis ductus venosus  lig. venosum) vv. efferentes hepatis  vv. hepaticae

57 Vena portae preduodenalis Vena portae preduodenalis rare


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