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35 Cards in this Set
- Front
- Back
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What are the 2 divisions of the circulatory system?
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1. Lymphatic
2. Cardiovascular |
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Are arteries efferent or afferent vessels?
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Efferent
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What is the route of blood for elastic arteries?
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From the heart to major regions of the body
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What are the 3 efferent vessels in the body?
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Elastic arteries, muscular arteries and arterioles
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What are the afferent vessels in the body?
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Venules, medium veins, large veins
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What are the 3 tunics found in the body?
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1. Tunica intima
2. Tunica media 3. Tunica adventitia |
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Describe the characteristics of the tunica intima (inner coat).
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-formed of endothelium, subendothelial layer of CT and sometimes, an internal elastic lamina.
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What type of epithelium makes up the endothelium?
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Simple squamous epithelium, supported by a basal lamina
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What is the subendothelium composed of?
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It is scattered with smooth muscle cells that produce the CT fibers and matrix of this layer
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What is the composition of the internal elastic lamina?
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It is a sheet of elastin with fenestrae that allow materials to diffuse deep into the vessel wall.
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What is the function of elastic arteries and name some examples of elastic arteries.
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Conduct blood from heart. Aorta, brachiocephalic, common carotids, subclavians, common iliacs
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Describe the tunica intima of elastic arteries
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-Thick
-No distinct internal elastic lamina |
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Describe the tunica media of elastic arteries
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-40-70 elastic laminae
-Alternating smooth muscle cells -reticular fibers -Proteoglycans -Glycoproteins -No distinct external elastic lamina |
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Describe the tunica adventitia of elastic arteries
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-Thin and unremarkable except for large vasa vasorum
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What is the function of muscular arteries and name some examples.
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Distribute blood to specific body regions. Named to specific body region (axillary, brachial, radial, ulnar, femoral, etc)
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Describe the tunica intima of muscular arteries.
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-Thin
-Smooth muscle cells -Prominent internal elastic lamina |
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Describe the tunica media of muscular arteries.
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-3-40 layers of helically oriented smooth muscle cells (contraction regulates blood flow)
-Elastic lamellae -External elastic lamina (in larger vessels) |
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Describe the tunica adventitia of muscular arteries.
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-Thick
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Describe the characteristics of arterioles.
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-Branches of small muscular arteries
-Diameter <0.5 mm -Branch into metarterioles -Metarterioles lead to capillary bed |
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Describe the tunica intima of arterioles.
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-Thin
-Internal elastic lamina |
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Describe the tunica media of arterioles.
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-1-2 layers of circular smooth muscle cells
-No external elastic lamina |
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Describe the tunica adventitia of arterioles.
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-Thin
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Describe the tunica media of metarterioles.
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-Discontinuous smooth muscle cells.
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What is an arteriovenous anastomoses?
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In some tissues, like skeletal muscle and the skin of hands and feet, arterioles bypass capillary beds and divert blood directly into venules.
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What is the function of arterioles?
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To control blood flow to capillary bed
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Describe capillaries
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-Arterioles branch into capillaries
-7-9 micrometers in diameter -Tunica intima: endothelium, basal lamina. -Tunica media: intermittent pericytes. -Thin tunica adventitia is sometimes visible. |
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What is a pericyte?
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-Derived from mesenchyme and contain contractile proteins (actin, myosin, and tropomyosin)
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What is the function of a pericyte?
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-It contracts to control blood flow through the capillary and participate in their repair following vascular injury.
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What are the 4 types of capillaries?
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1. Continuous (somatic)
2. Fenestrated (visceral) with diaphragms 3. Fenestrated without diaphragms 4. Discontinuous, sinusoidal |
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Where are continuous(somatic) capillaries found?
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Muscle tissue, exocrine glands, CT, nervous tissue.
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Where are fenestrated(visceral) with diaphragm capillaries found?
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Kidney, intestine, endocrine glands
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Where are fenestrated without diaphragm capillaries found?
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Renal glomerulus
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Where are discontinuous, sinusoidal capillaries found?
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Spleen, liver, bone marrow
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What are the characteristics of continuous (somatic) capillaries?
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-Highly impermeable
-Continuous endothelium -Tight junctions -Complete basal lamina -Pinocytotic vesicles ferry macromolecules bi-directionally (except in CNS) -It forms the blood brain barrier |
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Describe the characteristics of fenestrated (visceral) capillaries.
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-More permeable
-Fenestrated endothelium -Complete BL -Diaphragms present |
