Flashcards in Histology Deck (48)
Where is the most blood in the body?
What is the inner, middle and outer layers of blood vessels?
1. Tunica intima
2. Tunica media
3. Tinica adventitia
Describe the tunica intima?
Made up of single layer of squamosu epithelial cells termed endothelial cells (collectivly endothelium) supported by a basal lamina and thin layer of connective tissue.
Describe the tunica media?
Made up of predominantly muscle (some areas elastic tissue). It varies and sometimes disapears.
What is the tunica adventitia made from?
Supporting connective tissue
What are the very largest arteries termed?
What do elastic arteries have that provides elastic recoild?
Sheets of elastic fibres
What are the elastic arteries own vascular supply called?
What does Verhoeff's/Masson trichrome stain do to elastic fibres, collagen and smooth muscle?
Elastic fibres - black
Collagen - green
Smooth muscle cells - red
What does the tunica intima extend to?
An internal elastic membrane
What seperates the tunica media nad tunica adventitia?
External elastic membrane
What does Modified van Gieson's stain do to collagen, cytoplasm and elastin?
Collagen - red
Cytoplasm - yellow
Elastin - black
What are capillaries essentially composed of?
Endothelial cells and a basal lamina
What do capilarries often have ar intervals just outside the basal lamina?
What are the three types of capillary?
1. Continuous capillaries
2. Fenestrated capillaries
3. Sinusoidal or discontinuous capillaries
What types of capillaries are found in muscle, connective tissue, lung, skin and nerves?
What capillaries are found in mucosa of gut, endocrine glands and glomeruli of the kidney?
What capillaries lack basal lamina and have large gaps through which macromolecules, and in some cases even cells can pass. Found in liver, spleen and bone marrow?
Sinusoidal or discontinuous
What are important sites for exchange e.g. cells moving into the tissue in inflammation?
In microvasculature, what are small arterioles connected to?
Postcapillary venules through a network of metarterioles, throughfare channels and capillaries
What are composed of smooth muscle, found at the beginning of capillaries and help control flow through the network?
What are the three layers of the heart from outside to inside?
What does Azan trichrome stain nuclei, collagen and muscle?
Nuclei - red
Collagen - blue
Muscle - red
What lines the entire inner surface of the heart, including the valves?
What are the 4 features of the structure of the endocardium?
2. Basal lamina
3. Thin layer of collagen fibres
4. Layer of denser connective tissue
What else is there present in the endocardium that is made of loose connective tissue, contaisn small blood vessels and nerves and the branches of the impulse conducting system?
What has this structure: bundles and layers of c ontractile cardiac muscle fibres, individual muscle fibres are surrounded by delicate, collagenous connective tissue with a rich network of capillaries?
What has intervalated discs passing across the fibres at irregular intervals?
What do intercalated discs allow?
Attachment of cells and spread of electrical activity
What structure is this - on the surface of the heart, a single layer of flattened epithelium called mesothelium, basal lamina, fibroelastic connective tissue and in some places adipose tissue?
Where are large branches of the coronary blood vessels found?
In the epicardium
What are the two parts of the pericardium?
Fibrous and serious
What is the name of a sac of tough fibrocollagenous connective tissue?
What is made up of a layer of simple squamous epithelium (mesothelium), backed by a basal lamina and connective tissue. The serous pericardium lines the inner surface of the fibrous pericardium (where it is termed the parietal serous pericardium), and covers the surface of the heart (where it is termed the visceral serous pericardium)?
What seperates the two mesothelial layers of the pericardium?
Thin pericardial cavity which contains serous fluid to help heart movement lubrication
What forms the fibrous skeleton of the heart?
Bands of fibrous connective tissue around the heart valves, between the atria and between the ventricles
What is the outer layer of heart valves?
Endothelial layer with basal lamina
What do heart valves also have a layer of?
Collagen and elastin fibres
What is a core dense connective tissue, that is in continuity with the fibrous skeleton?
What are the leaflets of the valves seperating the atria from the ventricles (mitral and tricuspid) anchored by?
Collagenous strands called the chordae tendineae, which merge with the lamina fibrosa
What cells are small, appear pale, have few myofibrils, little glycogen and no proper T-tubules system?
Where are Purkinje fibres found?
In the subendocardial layer just deep to the endocardium
What fibres have abundant glycogen, no T-tubules, no intercalated discs and sparse actin and myosin filaments, which tend to be found at the periphery of the cells?
What structures distribute the excitatory activity such that ventricular contraction generally occurs from inferior to superior?
What do lymphatic capillaries begin as?
What does interstitial fluid contain?
Lipids, ins, proteins and occasional cells
How do lymphatic vessels produce flow as they do not have a central pump?
Smooth muscles in walls, hydrostatic pressure in the tissue and compression of the vessels by voluntary muscle, combined with valves in the vessels, produces flow