Cardiovascular system II Flashcards
(106 cards)
Systemic circulation
Blood from the heart is distributed around
the body before returning to the heart.
Pulmonary circulation
Blood from the heart to the lungs and
back to the heart.
Main role of capillaries
Exchange of
substances between blood and cells / tissues
Arteries & Arterioles
Location
Blood content
Pressure
Valves?
Away from heart
Oxygenated
High pressure
No valves
Veins & venules
Location
Blood content
Pressure
Valves?
Towards the heart
Deoxygenated
Low pressure
Valves
How does the structure of capillaries support their main role?
Capillaries contain only one layer of
cells (the ‘endothelium’).
Inner layer of blood vessels
Tunica intima
Middle layer of blood vessels
Tunica media
Outer layer of blood vessels
Tunica externa
3 functions/ characteristics tunica intima
endothelium (epithelial tissue)
protects the vessel wall & secretes chemicals.
Monitors changes in the blood
2 characteristics Tunica media
Smooth muscle
Controls blood vessel diameter
Tunica externa made from
elastic and collagen fibres
Which muscle type supports the return of venous blood to the heart?
Skeletal muscles
Which transport process supports the capillary exchange of gases?
Diffusion
Which transport process supports the capillary exchange of nutrients?
Facilatated diffusion and active transport
Which transport process supports the capillary exchange of water?
osmosis
Where is most blood found in the body?
64% blood in systemic veins / venules.
* 13% in systemic arteries / arterioles.
What is the hepatic first pass?
Venous blood passes from the
digestive tract, spleen and
pancreas directly to the liver
Portal vein
The vessel that carries the
absorbed substances from the GIT, spleen pancreas to the liver
Which nervous system stimulates vasoconstriction?
Sympathetic nervous
How do vasoconstriction and vasodilation impact blood pressure?
Vasoconstriction - increases blood pressure
Vasodilation - reduces blood pressure
Heart location
The heart rests on the
diaphragm, in the thoracic
near the midline, pointing left.
Apex 5th intercostal space.
Heart key facts
fist-sized muscular
organ
Blood pumps through 60k
miles of blood vessels
12 cm long, 9 cm wide
250 g in females. 300 g in males
Endocardium
Inner lining of the heart
Smooth endothelium
Provides a smooth lining