Histology Flashcards
True or False: Cardiac muscle contains many nuclei
False; only 1 or 2
True or False: Cardiac muscle nuclei are located centrally
True
True or False: cardiac muscle is striated
True
How many layers is the heart wall composed of and what are they
3 distinct layers: an outer epicardium, a middle myocardium and an inner endocardium
Which cell type is in the epicardium
simple squamous epithelium
True or false: cardiac muscle does not contain intercalated discs
False
What type of junctions does the intercalated discs contain
Gap and adhering junctions
Which of the two junctions in intercalated discs is responsible for electrical conduction
Gap junctions
What is the role of purkinje cells in the heart
electrical impulse conduction
A conducting system for initiation and propagation of rhythmic depolarizations is formed by which cell type of the heart
Purkinje fibers
Which layer of serous pericardium lines the outer surface of the heart (visceral or parietal)
Visceral layer
What type of cells line the percardial cavity
Mesothelial cells
What are the three layers of heart valves
fibrosa, spongiosa and ventricularis
The ventricularis layer of the heart valves continue into which structure in the AV valves
chordae tendineae
What is the name of the cells in the SA and AV nodes that do not contain intercalated discs
nodal cardiac muscle cells
What are the three layers of arteries and veins
tunica intima, tunica media and tunica adventitia
What are the three components of the tunica intima layer
endothelium, subendothelial layer and internal elastic membrane
What is the function of the external elastic membrane
separates the tunica media from the tunica adventitia
Which layer of blood vessels consists of circumferentially arranged layers of cells
tunica media
Which layer of blood vessels is composed of longitudinally arranged collagenous tissue and elastic fibers
tunica adventitia
Tunica adventia is thicker in veins or arteries
veins
Which layer of blood vessels contain a system of vessels called the vasa vasorum
tunica adventitia
What is the function of the vasa vasorum
supplies blood to the vascular walls themselves
Function of the nervi vasorum
control contraction of the smooth muscle in the vessel walls
Which layer of blood vessels contain a system of vessels called the nervi vasorum
tunica adventitia
What is the shape of the endothelial cells in blood vessels
flattened, elongated, and polygonally
Example of three receptors found on the luminal surface of endothelial cells in blood vessels
low-density lipoprotein [LDL], insulin, and histamine receptors
Which size arteries are elastic arteries
large arteries
Which size arteries are muscular arteries
medium arteries
Characteristics of large arteries
- multiple sheets of elastic lamellae in their walls.
- tunica intima consists of endothelium, subendothelial connective tissue, and an inconspicuous internal elastic membrane
- Endothelial cells participate in the structural and functional integrity of the vascular wall
- tunica media consists of multiple layers of vascular smooth muscle cells separated by elastic lamellae
- thin layer of tunica adventitia
Characteristics of medium arteries
- more smooth muscle and less elastin in the tunica media
- tunica intima is thinner and contains a prominent internal elastic membrane
- tunica media is composed almost entirely of vascular smooth muscle
- tunica adventitia is thick and separated from the tunica media by an external elastic membrane
Characteristics of small arteries
- smooth muscle in the tunica media
- tunica intima has an internal elastic membrane
- gap junctions may be found between endothelial cells and the smooth muscle cells of the tunica media
- tunica adventitia is a thin, ill-defined sheath of connective tissue that blends with the connective tissue
Characteristics of capillaries
- smallest diameter blood vessels
- a single layer of endothelial cells and their basal lamina
What are the different types of capillaries
continuous, fenestrated, and discontinuous (or sinusoidal)
Characteristics of continuous capillaries
- ound in connective tissue; cardiac, skeletal, and smooth muscles; skin; lungs; and the CNS
- uninterrupted vascular endothelium that rests on a continuous basal lamina
Characteristics of fenestrated capillaries
- found in endocrine glands and sites of fluid or metabolite absorption, such as the gallbladder, kidney, pancreas, and intestinal tract
- endothelial cells have numerous circular openings known as fenestrations
- continuous basal lamina
- a thin, nonmembranous diaphragm across its opening
Characteristics of discontinuous capillaries
- found in the liver, spleen, and bone marrow
- larger in diameter and more irregularly shaped than other capillaries
- Vascular endothelial cells lining these capillaries have large openings in their cytoplasm and they are separated by wide, irregular, intercellular gaps
- discontinuous basal lamina
What are the types of veins
Venules, small, medium and large veins
what is used to differentiate between a postcapillary venule and a muscular venule
muscular venules have a tunica media
Which type of vein usually accompany arteries
medium veins
which type of vein is continuous which muscular venules
small veins
3 examples of large veins
superior and inferior vena cava and hepatic portal vein
Characteristics of small veins
- diameters vary from 0.1 to 1 mm
- All three tunics are present
- Tunica media usually constitutes two or three layers of vascular smooth muscle
- thicker tunica adventitia
Characteristics of medium veins
- diameter of as much as 10 mm
- valves
- three tunics of the venous wall are most evident in medium-sized veins
Characteristics of large veins
- tunica media is relatively thin
- tunica adventitia is relatively thick
- diameter greater than 10 mm
Characteristics of lymph vessels
- more permeable than blood capillaries
- collect excess protein-rich tissue fluid
- lack a continuous basal lamina
- Anchoring filaments extend between the incomplete basal lamina
