Anatomy of CVS 2 Flashcards
Describe the structure of the blood vessels
3 tunics: tunica intima(endocardium), media(myocardium), externa/adventitia(epicardium)
Arteries vs veins
Arteries smaller diamater, thicker wall than accomponing vein
-Arteries thick media thin adventina wheras veins thin media and thick adventitia
Cross sectional area of arteries, arterioles and capillaries
Capillaries (1)
Arterioles (2)
Arteries (3)
Types of arteries
- Elastic
- Muscular
- Arterioles
Elastic arteries function + state example
- large conducting
- aorta, common carotid, pul.A
Muscular arteries function + state example
- distributing arteries
- coronary arteries, radial, femoral
Function of arterioles
- terminal branches which supply blood to capillary bed
- control BF to capillary beds + BP ( systemic)
Features of elastic arteries
- stretched during systole
- during diastole, heart relaxes + pressure falls. Artery recoils hence maintaining pressure on the blood
- recoil + stretchability is due to presence of elastic fibres in T.media in the form of layers = laminae
- Elastic fibres secreted by SM cells
Features of muscular arteries
- controls distribution of blood to regions
- sandwich of elastic fibres
- thick T media has only SM cells
- no elastic laminae between muscle cells in T media
- Elastic fibres in sheets called internal elastic lamina ( IEL) just under the epithelium and outer elastic lamina (OEL) between T media + T adventitia
Features of arterioles
- No IEL/T.adventia
- 1-2 Smooth muscle layers in T.media allow constriction/dilation
- Innervated by sympathetic nerves in order to control diameter of vessel
Function of capillaries
-gas exchange ( nutrients, gases)
Structural features of capillaries
- T.intima only ; endothelium on BM
- No T.media/T.adventitia
- Pericytes; incomplete layer of cells surrounding BM which has contractile properties which help control flow of blood in capillaries
- low BP in capillaries
Types of capillaries
Continious, fenestrated, discontinous
Function + features of continous capillaries + examples
- controls what is exchanged
- material must pass through cell/inbetween C.junctions(also controls)
- selective transport mechanisms
- Muscle
Function features, + example of Fenestrated capillaries
- have fernestrations ( pores)
- with/without protein diaphragms
- diaphragms filters molecules by MW +/or charge
- endocrine glands, kidney renal corpuscle
Function, features + example of discontinous capillaires
- gaps between endothelial cells ( and BM)
- allws free passage of fluid + cells
- liver, spleen, bone marrow
What are sinusoids?
- large diameter discontinous capillaries
- found where large amount of exchange takes place
- T.intima contains phagocytic cells which digests old RBCs and toxins
- liver, some endocrine glands
Capillary beds and arteriovenous shunts functipm
- bypassing of capillary beds in order to conserve heat
- skin for thermoregulation
-precapillary sphincter
Describe structure of the veins
T.intima thin
-IEL + OEL thin/absent
-T.media thin/absent
T adventitia present - collagenous tissue
Superficial vs Deep veins
Superficial; thick walled, no surrounding support
Deep; thin walled, surrounding support from deep fascia and muscles
What is the function of lymphatic system
- drains tissue fluid lost from capillaries
- drains into systemic venous system
- valves
Where are lymph nodes found?
-nodes found alongside major veins and around major arteries
Describe the structure of the lymph capillaries
- blind ended capillaries
- lined by very thin endothelium, no fenestrations
- absent/rudimentrary basal lamina
- anchoring filaments; collagenous filaments link endothelial cell to surrounding tissue keeping lumen open
- no RBCs in lumen
- may be found in T.adventia of large vessels
BV as organs
Nerve supply
- symp ( eg skin)
- symp.para ( eg heart)
Blood supply
-vasa vosoru,
Lympatics
-in T.adventiitia ( of big vessels)
