Histology Flashcards
What are the three layers of a blood vessel?
Tunica intima - single layer of squamous epithelial cells with a basal lamina and a thin layer of connective tissue
Tunica media - mainly muscle with elastic tissue in places
Tunica adventitia - supporting connective tissue
What is the vasa vasorum?
the blood vessels of the blood vessels
What are pericytes?
connective tissue cells with contractile properties found just outside the basal lamina of capillaries
What are the three types of capillaries?
Continuous capillaries - most common
Fenestrated capillaries - slightly larger pores in wall - found in gut mucosa, endocrine glands and glomeruli of the kidneys
Sinusoidal/Discontinuous capillaries - lack basal lamina and have large pores - found in liver, spleen and bone marrow.
What part of the circulatory system are an important site for inflammatory cells moving into tissues?
post-capilliary venules
What are precapilliary sphincters?
Smooth muscle at the beginning of the capillaries that are important in controlling the flow of blood through the network.
Describe a cardiac muscle cell
striated
intercalated discs between cells
single nucleus in the centre of every cell
Describe the structure of the epicardium
A single layer of flattened epithelium (mesothelium) with a basal lamina and fibroelastic connective tissue (and adipose tissue in some places)
What two parts make up the pericardium?
Fibrous pericardium - tough fibrocollagenous connective tissue
Serous pericardium - parietal serous pericardium and visceral serous pericardium (epicardium)
What is the name of the collagenous strands that attach the valves to the papillary muscles?
chordae tendineae
What are pacemaker cells?
Modified muscle cells (not nervous cells)
They are smaller than normal muscle cells
Embedded in a more extensive matrix of connective tissue
Paler than cardiac cells
Non-contractile
SA and AV node
What are conducting cells?
Bundle of His and Purkinje fibres
Modified muscle cells (not nervous cells)
Bundle of His cells are smaller than normal muscle cells
Purkinje fibre cells are larger than normal cardiac cells
