The anatomy of the cardiovascular system 2 Flashcards
what is the three layers of the blood vessels
Tunica initma
Tunica media
Tunica adventitia
What is the structure of the tunica initma
Inner most layer
Simple squamous epithelium
lying on connective tissue and basement membrane
What is structure of the tunic media
Middle layer
Smooth muscle tissue
Elastic tissue
What is the structure of the tunica adventitia
Outer most layer
Fibrous connective tissue - collagen
elastic fibres present
What is the differences between veins and arteries
Arteries smaller diameter than accompanying vein
Arteries thicker wall than accompanying vein
Arteries thick media thin adventitia
Veins thin media thick adventitia
What is the difference between arteries and arterioles
arteries have greater diameter but smaller total cross section area compared to arterioles
What is the different types of arteries
elastic
Muscular
arterioles
What is the function of the elastic arteries and an example of one
large conducting
– eg: aorta, common carotid, pulmonary
What is present in the structure of elastic arteries, and what property does this allow
Layers of elastic fibres allows it to be stretched under pressure - and maintain pressure
Where is the elastic fibres present in the elastic arteries and what si the name of the arrangement
elastic fibres in T. Media in the form of layers = laminae
Where are the fibres in elastic arteries secreted from
smooth muscle
What is the function of the muscular arteries
Controls distribution of blood to regions
What is present in the structure of the muscular arteries which allows it to fulfil its functions
Thick T media has smooth muscle cells
Where can the elastic fibres be found in muscular arteires
No elastic lamina between muscle cells in T. media
Elastic fibres are found under epithelium (internal elastic laminae) and between T.media and T. adventitia (external elastic laminae)
What is the structure of the arterioles
T. Intima - endothelium + BM
T. media - 1- 2 layers of smooth muscle
T. adventia - not present
What kind of nerve intervention supplies the arterioles
Rich sympathetic nerve innervation
What is the systolic and local function of the arterioles
Control blood flow to capillary beds (local)
Control blood pressure (systemic)
What is the function of the capillaries
main exchange for nutrients and gasses
What is the structure of the capillaries to suit its function
Therefore very thin walled
T. intima only – endothelium on BM
No T. media
No T. adventitia
What is present in capillaries which helps control blood flow and what is this
Pericytes - contractile cells
incomplete layer of cells surrounding basement membrane
If the Sum of diameters of all capillaries in body > diameter of aorta what does this mean about the blood pressure
blood pressure is low
what is the average diameter of the capillaries
4-15µ
What is the three types of capillaries
Continuous
Fenestrated
Discontinuous
What is the structure of the continue capillaries and its function and where would you find them
continuous epithelium linning
controls what is exchanged through selective transport
muscle
What is the structure of fenestrated capillaries and where would you find them
Gaps/pores present of open protein membrane
endocrine glands, kidney renal corpuscle
What is the structure of discontinuous capillaries and what function does this allow
Gaps between endothelial cells (and basement membrane)
Allow free passage of fluid and cells
Where is discontinuous capillaries found
Liver, spleen, bone marrow
what is a Sinusoids
Large diameter discontinuous capillaries
Where would sinusoids be typically found and examples
Places where a large amount of exchange take place
Liver
endocrine glands
What does the t. intimate contain is sinusoids
Phagocytes
what is precapillary sphincter
band of smooth muscle that adjusts blood flow into capillaries
What does function of the AV shunts by the precapillary spinchter allow
Bypass the capillaries to allow thermo regulation
What is the structure of viens
T.intima is thin
thin or absent laminae- not alot of elastic fibres
T.media v thin or absent
T adventitia - collagenous tissue
What are the valves structure in the viens
endothelial projection into lumen
What is the differences with superficial vs deep veins
Superficial - Thick walled - No surrounding support Deep - Thin walled - Surrounding support from deep fascia and muscles
What does the superficial ultimately drain into
deep veins
What is function of the lymphatic system
Drains tissue fluid lost from blood capillaries
where does the lymphatic system drain into
systemic venous system
Where is nodes most commonly found
alongside major veins and origins of major arteries
What directs the flow in Lymphatic system
Valves
What is the structure of lymph capillaries
Blind ended capillaries
Lined by very thin endothelium - simple squamous
No fenestrations
Absent / rudimentary basal lamina
What is the lumen maintained at in lymph capillaries
-ve Hydrostatic pressure
what keeps the lumen open
Anchoring filaments – fine collagenous filaments link endothelial cell to surrounding tissue keeping lumen open
what isn’t present in the lumen
RBC
What is the nerve supply to BV as organs
Sympathetic eg. skin
Sympathetic + parasympathetic eg. heart
when blood vessels are so big they need their own nutrients what are the vessels suppling it called
Vasa vasorum
Where does the lymphatic lie in blood vessel organs
T. adventitia
