VESSELS general overview - Univerzita...
Transcript of VESSELS general overview - Univerzita...
VESSELS
general overview
© David Kachlík 30.9.2015
• tunica intima
• subedothelial layer of connective tissue
• membrana elastica interna
• tunica media
• membrana elastica externa
• tunica adventitia= tunica externa
GENERAL STRUCTURE OF VASCULAR WALL
© David Kachlík 30.9.2015
General structure of vascular wall
• tunica intima
• tunica media
• tunica
adventitia
(externa)
© David Kachlík 30.9.2015
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
© David Kachlík 30.9.2015
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
© David Kachlík 30.9.2015
Tunica media
• smooth muscle cells
– spiral arrangement
• elastic a collagen fibers (type III)
• lamina elastica externa
– only in thicker arteries
© David Kachlík 30.9.2015
Tunica adventitia (externa)
• fibroblasts
• collagen fibers (type I)
• elastic fibers
• vasa vasorum
• nervi vasorum
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
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 © David Kachlík 30.9.2015
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© David Kachlík 30.9.2015
Elastic arteriesaorta, truncus pulmonalis, a. subclavia,
axillaris, iliaca, femoralis, thoracica int.
© David Kachlík 30.9.2015
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© David Kachlík 30.9.2015
Elastic artery (van Gieson + elastin)
© David Kachlík 30.9.2015
Elastic artery (elastin)
© David Kachlík 30.9.2015
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
© David Kachlík 30.9.2015
Muscular artery
(HE) (van Gieson + elastin)
© David Kachlík 30.9.2015
Arterioles = Arteriolaecaliber < 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© David Kachlík 30.9.2015
Arteriola (HE)
© David Kachlík 30.9.2015
Arteriola (HE)
© David Kachlík 30.9.2015
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 - 3-5 mm
• glomus cells – large nucleus, vesicles with catecholamines
• shield cells – cover neural endings as glia
© David Kachlík 30.9.2015
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 96 000 km
– formed by endothelial cells on basal lamina
© David Kachlík 30.9.2015
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)
© David Kachlík 30.9.2015
Capillary bed
(HE)
© David Kachlík 30.9.2015
Capillary types
• somatic capillaries– muscle, conncetive tissue, exocrinne glands (pinocytar
vesicle in the wall), nervous tissue (no vesicles)
• fenestrated (visceral) capillaries with diaphragms– fenestrations 60-80 nm (quick metabolic exchange)
– kidneys, gut, endocrinne glands
• fenestrated capillaries without diaphragms– glomeruli in kidney
• sinusoids– caliber 30-40 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 © David Kachlík 30.9.2015
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© David Kachlík 30.9.2015
Somatic capillary (EG)
© David Kachlík 30.9.2015
Somatic capillary (EG)
© David Kachlík 30.9.2015
Fenestrated capillary (EG)
© David Kachlík 30.9.2015
Fenestrated capillary
(EG)
© David Kachlík 30.9.2015
Other structures of vascular wall
• vasa
vasorum
• vasa
nervorum
• nervi
vasorum
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
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)© David Kachlík 30.9.2015
Vessel network arrangement
• terminal (retina, spleen, kidney)
• functionally terminal (heart, brain)
• anastomotic
angiogenesis – hypoxia is the strongest
factor !
© David Kachlík 30.9.2015
Clinical relevance
• aneurysma
• atherosclerosis (athere + skleros)
• necrosis, infarctus
• air embolism in large cervical veins
• varices
© David Kachlík 30.9.2015
Blood distribution in vessels
• veins 64%
• arteries 13%
• capillaries 7%
• heart 7%
• lungs 9%
© David Kachlík 30.9.2015
Blood distribution in organs
• heart (coronary arteries) 5%
• brain 15%
• muscles 15%
• viscera 35%
• kidneys 20%
• skin, skeleton 10%
according to Stingl
© David Kachlík 30.9.2015
Development of arterial system
© David Kachlík 30.9.2015
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© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Day 20-22
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Pharyngeal arch arteries derivates
• 1st pair – arteria maxillaris + carotis externa
• 2nd pair – arteria stapedia
• 3rd pair – central – arteria carotis communis
– peripheral – arteria carotis interna
© David Kachlík 30.9.2015
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
© David Kachlík 30.9.2015
Pharyngeal arch arteries derivates
• 5th – Ø
• 6th pair
– left central left pulmonary artery
peripheral ductus arteriosus (Botali)
– right central right pulmonary artery
peripheral Ø
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Arteriae omphalomesentericae
(vitellinae)
• number of paired arteries
• supply yolk sac
• develop in vascular supply of gut → truncus
coeliacus, arteria mesenterica superior et inferior
© David Kachlík 30.9.2015
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
© David Kachlík 30.9.2015
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 7th
segmental artery
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Malformation of arteries
• course changes
• clinically relevant:
– a. radialis
• a. brachioradialis (14%)
– a. ulnaris
• a. brachioulnaris superficialis (3%)
© David Kachlík 30.9.2015
Development of venous system
© David Kachlík 30.9.2015
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© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Vena cava inferior
• v. omphalomesenterica intraembryonica
pars hepatica VCI
• anastomosis subcardinalis + v.
subcardinalis dx. pars subcardinalis VCI
• developmental anomalies 1-2%
– infrarenal duplication
© David Kachlík 30.9.2015
Vena portae
• vv.
omphalomesentericae
intraembryonicae
• vv. afferentes hepatis
• ductus venosus lig.
venosum)
• vv. efferentes hepatis
vv. hepaticae
© David Kachlík 30.9.2015
Vena portae
preduodenalis
rare
© David Kachlík 30.9.2015