Anatomy of the CVS 2 Flashcards
What is the CVS composed of?
Heart
Arteries
Capillaries
Veins
What does the heart act as?
Pump
What do arteries do?
Distribute blood away from the heart
What do veins do?
Collect and return blood to the heart
What do capillaries do?
Exchange nutrients
What does the structure of a blood vessel consist of?
Tunica externa
Tunica media
Tunica intima
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What is A?
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Tunica externa
What is B?
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Tunica media
What is C?
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Tunica intima
What is the structure of the heart wall composed of?
Endocardium
Myocardium
Epicardium
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How is the structure of the heart and blood vessels similar?
The heart is like an expanded, folded muscular blood vessel
What is the tunica intima composed of?
Epithelium
Basement membrane
Connective tissue
What is the tunica media composed of?
Muscle
Elastic tissue
What is the tunica externa (adventitia) composed of?
Fibrous connective tissue
What are some general differences between arteries and veins?
Arteries have a smaller diameter
Arteries have a thicker wall
Arteries thick media and thin adventitia
Veins thin media and thick adventitia
How does the media and adventitia compare in arteries and veins?
Arteries have thick media and thin adventitia
Veins have thin media and thick adventitia
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What is A?
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Arteries
What is B?
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Vein
How does the individual diameter compare between arteries, arterioles and capillaries?
Arteries > Arterioles > Capillaries
How does the total cross sectional area compare between arteries, arterioles and capillaries?
Arteries < Arterioles < Capillaries
How does the lumen size compare between:
Aorta
Elastic arteries
Muscular arteries
Arterioles
Capillaries
Venules
Small veins
Medium veins
Large vains
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What are the different types of arteries?
Elastic (large conducting)
Muscular (distributing)
Arterioles (terminal branches)
How would you describe elastic arteries?
Large conducting
What are examples of elastic arteries?
Aorta
Common carotid
Pulmonary
How would you describe muscular arteries?
Distributing arteries
What are examples of muscular arteries?
Coronary arteries
Radial
Femoral
What do elastic arteries act as?
Pressure reservoir
How do elastic arteries function?
Stretched during systole
During diastole heart relaxes and pressure falls, artery recoilds therby maintaining pressure on the blood
What is the recoil and stretch ability of elastic arteries due to?
Presence of extensive amounts of elastic fibres in tunica media
What are elastic fibres of elastic arteries secreted by?
Smooth muscle
Where are the vast amounts of elastic fibres in elastic arteries found?
Tunica media
What is present in the histology of elastic arteries?
Elastic laminae
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What is present in the thick tunica media of muscular arteries?
Smooth muscle cells
What is not present in the tunica media of muscular arteries that is present in elastic arteries?
Elastic laminae
Where are the elastic fibres in a muscular artery?
Concentrated in 2 well defined sheets called internal elastic lamina (IEL)
How do arterioles differ from other arteries?
No internal elastic lamina
How many layers of smooth muscle is present in the tunica media of arterioles?
1-2 layers
What layer is missing from arterioles?
Tunica adventitia
What do arterioles control?
Blood flow to capillary bed (local)
Blood pressure (systemic)
What do arterioles have a rich innervation of?
Sympathetic nerves
What is the function of capillaries?
Main exchange site for nutrients and gases
What can you say about the walls of capillaries?
1 cell thick
What layers are capillaries missing?
No tunica media or tunica adventitia
What helps to direct blood flow in capillaries?
Pericytes
What are pericytes?
Incomplete layer of cells surrounding basement membrane which have contractile properties to help control flow of blood in capillaries
How is blood pressure in capillaries low?
Sum of diameters of all capillaries in the body is greater than the diameter of the aorta
What are the 3 kinds of capillaries?
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How do continuous capillaries control gas exchange?
Material must pass through cell or between cells (junctions can control)
Selective transport mechanisms
What is present on fenestrated capillaries?
Fenestrations (pores)
With or without protein diaphragms
What do protein diaphragms do?
Filter molecules by molecular weight and/or charge
Where are fenestrated capillaries found?
Endocrine glands
Kidney renal corpuscle
What is unique about discontinuous capillaries?
Gap between endothelial cells (and basement membrane) allowing free passage of fluid and cells
Where are discontinuous capillaries found?
Liver
Spleen
Bone marrow
What are sinusoids?
Large diameter discontinuous capillaries
Where are sinusoids found?
Where large amounts of exchange take place
What does the tunica intima of sinusoid capillaries contain?
Phagocytic cells
Where are sinusoid capillaries found?
Liver
Some endocrine glands
What can be used to bypass capillary beds?
Arteriovenous (AV) shunt
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Where are AV shunts found?
Skin for thermoregulation
Where does blood flow go after the capillary bed?
Small venule > small-medium sized vein > large vein
What are the different layers of a vein like?
Tunica intima is thin
Internal elastic lamina (IEL) is thin or absent
Tunica media is very thin or absent
Tunica adventitia is collagenous tissue
What are valves?
Endothelial projections into the lumen to prevent backflow
What are endothelial projections into the lumen to prevent backflow called?
Valves
What are the differences between superficial and deep veins?
Superficial veins are thick walled and have no surrounding support
Deep veins are thin walled and surrounding support from deep fascia and muscles
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What does the lymphatic system do?
Drains tissue fluid lost from blood capillaries
Where does the lymphatic system drain into?
Systemic venous system
Where are nodes of the lymphatic system found?
Alongside major veins and around origins of major arteries
What directs the flow in the lymphatic system?
Valves
Are fenestrations present in lymph capillaries?
No
Describe the structure of lymphatic capillaries?
Lined by very thin endothelial
No fenestrations
Absent/rudimentary basal lamina
What keeps the lumen of lymph vessels open?
Maintained at negative hydrostatic pressure
Anchoring filaments, fine collagenous filaments link endothelial cell to surrounding tissue to keep lumen open
What supplies blood to a blood vessel?
Vasa vasorum
Where are the lymphatics of a blood vessel?
Tunica adventitia