VM: Cardiac Muscle and Blood Vessels Flashcards
Where are muscular arteries typically found?
Main distributing branches of the arterial tree:
- radial
- femoral
- coronary
- cerebral
The nuclei within the tunica media belong to which cell type?
smooth muscle cells
Identify (1-3)
- Tunica adventitia
- Tunica media
- endothelial cell nuclei
What is the functional significance of fenestrated elastic laminae in elastic arteries?
The elasticicity of the elastic arteries helps to maintain constant atrial pressure (strech during systole, recoil during diastole)
Continuous capillaries are generally found in what type(s) of tissue? Describe them.
- cardiac muscle
- skeletal muscle
- brain and peripheral nerves
Endothelial cells are tightly attached to each other by junctional complexes (no fenestrations).
What two major cell-cell junction types are found in intercalacted disks?
Fascia adherens (transverse part)
Gap junctions (lateral part)
Some arterioles feature a pre-capillary spinchter to regulate the flow of blood into downstream capillary beds. Name this type of arteriole.
metarterioles
Sinusoidal capillaries are generally found in what type(s) of tissues? Describe them.
- bone marrow
- liver
- lymphoid organs
- some endocrine glands
Tortuous, unusually wide lumen (30-40um), fenestrations, endothelial gaps, discontinuous basal lamina
Accumulation of collagen (scar formation) in cardiac tissue is evidence of what?
Past myocardial infarction (MI)
Where are elastic arteries found?
Major distribution vessels, including:
- Aorta and inominate (brachiocephalic trunk)
- Common carotid and subclavian
- large pulmonary arteries
What type of blood vessel is this?
arteriole (large)
Name the three major layers of blood vessels
- tunica intima
- tunica media
- tunica adventitia
What is the functional significance of the intercalated disks?
they enable cell adhesion and electrical coupling of adjacent cardiac myocytes
What type of vessel is pictured here?
capillary
Fenestrated capillaries are generally found in what type(s) of tissues? Describe them.
- kidneys
- intestines
- some endocrine glands
contain fenestrations that may be opened or closed by diaphragms
Identify the structures indicated by arrows
capillary fenestrations
Why is the cross-sectional diameter of cardiac mycytes variable?
Cardiac myocytes are branched
Name some characteristics of arterioles
- external diameter of less than 100um
- wall thickness approximately equal to lumen diameter
- little or no subendothelial connective tissue
- 2-5 smooth muscle layers in the tunica media
- no external elastic lamina
- very thin tunica adventitia
Name some functions of the circulatory system
- transport of O2, nutrients, waste products, body fluid, solutes, and immune system components
- body heat homeostasis
Identify (1-3)
The vessel pictured here belongs to what category of atery?
- Tunica adventitia
- Tunica media
- Inner elastic layer
muscular artery
What are some possible interventions to promote re-endothelialization of blood vessels (and therefore, re-stenosis)?
- local administration of endothelial cell growth factors (i.e. VEGF)
- endothelial cell seeding
- estrogen-eluting stents to promote healing, reduce SMC migration/proliferation, and attract circulating endothelial cells.
Are cardiac myocytes typically branched?
How many nuclei are typically associated with each cardiac myocyte?
Where are the nuclei generally located in cardiac myocytes?
Yes
1-2
centrally
Identify the structures indicated by arrows
Intercalated disks
Identify (1-3)
What is the purpose of (3)?
- Tunica adventitia
- Tunica media
- vasa vasorum - blood supply to the vessel itself
Identify an intercalated disk
Identify (1-4)
- Internal elastic lamina
- Tunica media
- External elastic lamina
- Tunica adventitia
