What is the CVS composed of?
What does the heart act as?
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?
What does the structure of a blood vessel consist of?
What is A?
What is B?
What is C?
What is the structure of the heart wall composed of?
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?
What is the tunica media composed of?
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
What is A?
What is B?
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:
What are the different types of arteries?
Elastic (large conducting)
Arterioles (terminal branches)
How would you describe elastic arteries?
What are examples of elastic arteries?
How would you describe muscular arteries?
What are examples of muscular arteries?
What do elastic arteries act as?
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?
Where are the vast amounts of elastic fibres in elastic arteries found?
What is present in the histology of elastic arteries?
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?
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?
What layer is missing from arterioles?
What do arterioles control?
Blood flow to capillary bed (local)
Blood pressure (systemic)
What do arterioles have a rich innervation of?
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?
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?
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?
With or without protein diaphragms
What do protein diaphragms do?
Filter molecules by molecular weight and/or charge
Where are fenestrated capillaries found?
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?
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?
Where are sinusoid capillaries found?
Some endocrine glands
What can be used to bypass capillary beds?
Arteriovenous (AV) shunt
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?
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
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?
Are fenestrations present in lymph capillaries?
Describe the structure of lymphatic capillaries?
Lined by very thin endothelial
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?
Where are the lymphatics of a blood vessel?