Blood and Lymphatic Vessels Flashcards
circulatory system is divided into two components:
- blood vascular system
- lymphatic vascular system
system that transports blood
blood vascular system
system that collects and returns excess extracellular fluid (lymph) to the blood vascular system
lymphatic vascular system
The endothelium, which is the inner surface of blood vessels and lymphatic vessels are lined by flattened endothelial cells (_____).
Endotheliocytes
The fibrous elements in the intima and adventitia (mainly collagen) run ____ (along the length of the vessel)
longitudinally
The fibrous elements in the media (elastic tissue or muscle) run
Circularly
Elastic fibers, including those of the internal and external elastic laminae are often in the form of
fenestrated sheets
innermost coat of the wall of artery which is thin and appear scalloped or corrugated in the specimen.
Tunica intima
Tunica intima consists of:
- endothelium
- subendothelial layer of collagenous connective tissue
- internal elastic lamina
Thin wavy band of elastic fibers which separates the tunica intima from the next layer in medium-sized and large arteries
Internal elastic lamina
The middle, thickest and most prominent coat of the artery
Tunica media
consists predominantly of smooth muscles arranged in concentric layers, elastic fibers scattered between the muscle cells, and a well-defined external elastic lamina separating it from the outermost tunic
tunica media
this is the thinner outermost coat of composed principally of areolar connective tissue
tunica adventitia
tunica adventitia is composed principally of areolar connective tissue (primarily ____ & ____)
- type 1 collagen
- elastic connective tissue fibers
Small blood vessels called _____ & nerves may be found in this layer (what layer?____) which also penetrate the outer half of the tunica media
Vasa vasorum; tunica adventitia
are the largest of the arteries.
Elastic Arteries
Because they arise directly from the heart, they are subject to cyclic changes of blood pressure.
Elastic Arteries
- to adapt to the changes in blood pressure, an abundance of ____ are located in the walls of these vessels
- to provide structural stability and allow distention of the elastic arteries
- they also help in the maintenance of blood pressure in between heartbeats.
elastic fibers
____ constitute most of the arteries of the body
Muscular arteries
Muscular Arteries: _____ possess well-developed internal elastic laminae.
tunica intimae
Muscular Arteries: _____ is composed of many layers of smooth muscle cells, and its outer boundary in larger muscular arteries has an external elastic lamina.
tunica media
Muscular Arteries: _____ is also well supplied by vasa vasorum and nerve fibers
Tunica adventitia
These are the smallest arteries and are responsible for regulating blood pressure.
Arterioles
Arterioles: ______ is composed of an endothelium with a slight amount of subendothelial connective tissue.
Tunica intima
Arterioles: ______ is made up of a few layers of smooth muscle cells, but in small arterioles, only a single smooth muscle cell layer is found.
Tunica media
Arterioles: ______ is also slight with occasional fibroblasts
Tunica adventitia
Tunica mediais made up of a few layers of smooth muscle cells, but in small arterioles, only a ______ is found.
single smooth muscle cell layer
are very small vessels that consist of a single layer of endothelial cells surrounded by a basal lamina and occasional pericytes.
Capillaries
These vessels exhibit selective permeability, and they, together with venules, are responsible for the exchange of gases, metabolites, and other substances between the blood stream and tissues of the body.
capillaries
capillaries exhibit selective permeability, and they, together with ____are responsible for the exchange of gases, metabolites, and other substances between the blood stream and tissues of the body.
Venules
three (3) types of capillaries:
- continuous
- fenestrated
- sinusoidal
_____ lack fenestrate and possess a continuous basal lamina.
Continuous capillaries
Continuous capillaries are present in regions such as
- skeletal muscle
- lungs
- thymus
- peripheral nerve fibers
_____ are penetrated by relatively large diaphragm-covered pores. These cells are also enveloped by a continuous basal lamina.
Fenestrated capillaries
Fenestrated capillaries are located ______
- endocrine glands
- pancreas
- lamina propria of the intestines
They constitute the glomeruli of the kidneys
Fenestrated capillaries
They are enveloped by a discontinuous basal lamina
Sinusoidal capillaries
The intercellular junctions of their endothelial cells display gaps, permitting leakage of material into and out of these vessels.
Sinusoidal capillaries
Sinusoidal capillaries are located in the
- bone marrow
- liver
- lymph nodes
____ are low-pressure vessels, that conduct blood from the larger tissues of the body to the heart.
Veins
Also, many veins contain ______ in the lumen that prevent back flow of blood
valves
Veins contain at least twice the amount of blood compared to arteries. This is because the lumina of veins are much _____ arteries
larger than
These are the smallest veins into which capillaries drain. They are 20-3o um in diameter
Venules
Flattened or branching cells called ____ may be seen outside the basal laminae of small venules, while some muscle may be present in larger vessels.
Pericytes
Functionally, venules have to be distinguished from true veins. The ______ have considerable permeability and exchanges between blood and surrounding tissues can take place through them.
walls of venules
are sites where lymphocytes and other cells pass out of (or into) the blood stream
venules
compared to arteries, veins have
- thinner walls
- larger diameter
- wider lumen
___ are thin walled structures accompanied by a valve which carry lymph and are lined by endothelial cells, consequently the layer is composed of a thin smooth muscles
Lymphatic vessels
The critical role of the valve lies by preventing the back flow of lymph allowing the system to function even without a _____
central pump.
____ is the blood vessel with a relatively thick tunica media showing a prominent muscle content
Arteriole
____ is the blood vessel with a wide lumen and thin wall; latter seems to be composed only of the lining endothelium and a thin surrounding areolar connective tissue
Venule
____ is the thinnest walled blood vessel, the wall of which is just the lining endothelium; both tunica media and tunica adventitia have disappeared
Capillary
In stained specimen, contents of a lymph vessel appear as a fibrinous mass with very few cells, mostly _____
Lymphocytes
