Histology of heart/vessels Flashcards
What part holds the most blood from most to littlest
Peripheral veins 65%
Heart and Lungs 20%
Peripheral arteries 10%
Capillaries 5%
What are the 3 basic layers of the blood vessels
Inner layer: Tunica intima
Middle layer: Tunica media
Outer layer: Tunica adventitia
What is the Tunica intimacy made of
Single layer of squamous epithelial cells called endothelial cells supported by the basal lamina and a thin layer of connective tissue
What is the Tunica media made up of
Predominantly of smooth muscle
What is the Tunica adventitia made up of
Supporting connective tissue
What separates the tunica intimacy from the tunica media
layer of elastic tissue called the internal elastic membrane
What separates the tunica media and adventitia
layer of elastic tissue called the external elastic membrane
What are elastic arteries
Largest arteries like the aorta
They have many sheets of elastic fibres in the tunica media
What is the Vasa vasorum
The own vascular supply of large vessels
What are Arterioles and what are they mad of
Small arteries
Have tunica intimacy, only 1 or 2 layers of smooth muscle in the tunica media and almost no adventitia
What are meta arterioles
Smooth muscle are replaced by dis-continuous non-contractile cells called pericytes
terminated into capillaries
What are capillaries composed of
Endothelial cells and basal lamina
Often have pericytes which have contractile properties
What are continuous capillaries and where are they found
No gap between endothelium
muscle, connective tissue, lung, skin and nerve
What are Fenestrated capillaries and where are they found
Small gaps in endothelium but basal lamina is continuous
mucosa of gut, endocrine glands, glomeruli of kidney
What are Sinusoidal/Discontinues capillaries and where are they found
Large gaps in the endothelium and no basal lamina
Liver, spleen and bone marrow
What are post-capillary venules
Where capillaries drain into
Which are endothelial cell-lined and contain thin layer of connective tissue
What is the difference between a Vein and an artery
Thin tunica media
Thick tunica adventitia containing bundles of longitudinally orientated smooth muscle
Valves which are extension from the tunica intima
What are the 3 layers of the heart
Endocardium (inner layer)
Myocardium (middle layer)
Epicardium (outer layer)
What is the Endocardium made of
Endothelium
Basal lamina
Thin layer of collagen fibres
Layer of denser connective tissue
Some areas subendocardium
What is a subendocardium
loose connective tissue containing small blood vessels and nerves and branches of impulse conducting system
What is the structure of the Myocardium
Bundles and layers of contractile cardiac muscle fibres
Individual muscle fibres are surrounded by connective tissue with capillaries
What is the structure of the Epicardium
Surface: single layer of flattened epithelium called mesothelium
Basal lamina
Fibroelastic connective tissue and some places adipose tissue
What are the 2 parts of the pericardium
Fibrous pericardium (connective tissue)
Serous pericardium
What is the pericardium made up of
Layer of simple squamous epithelium (mesothelium) backed by basal lamina and connective tissue
