Cardiovascular System Flashcards
The heart pumps blood into two anatomically separate systems, what are these?
Pulmonary circulation
Systemic circulation
Which side the of the heart supplies the pulmonary circulation and which side supplies the systemic circulation?
The right side of the heart supplies the pulmonary circulation with deoxygenated blood, the left side of the heart supplies the systemic circulation with oxygenated blood
The CV system ensures a continuous flow of blood to all body cells, which physiologically adjusts to maintain an adequate blood supply. If the supply of blood, and therefore oxygen and nutrients in inadequate what are the consequences
Tissue damage & cell death
Arteries and arterioles carry blood ? from the heart
Away
Veins and venules carry blood ? the heart
Towards
What are the three layers of tissue to a blood vessel
Tunica Adventitia - outer layer of fibrous tissue
Tunica Media - middle layer of smooth muscle and elastic tissue
Tunica Intima - one cell thick layer of endothelium
Arterial walls are thicker than venous walls because?
They need to withstand the higher pressure of the blood in the arterial system
How are arteries adapted for higher blood pressures closer to the heart?
In the largest arteries the tunica media contains more elastic tissue and a little more smooth muscle allowing the vessel wall to stretch and absorb the pressure generated by the heart as it beats
Why are the smaller arteries referred to as resistance vessels
Systemic blood pressure is mainly controlled by the resistance the tiny arteries offer to blood flow
Describe the structure of a capillary
Capillaries consist of a single layer of epithelial cells sitting on a very thin basement membrane
Capillary function:
Allow for the exchange of substances between the blood and the tissue fluid which surrounds all body cells.
What are sinusoids and what are their functions
Sinusoids are capillaries that are significantly wider and leakier than normal. The walls are incomplete, their lumen is larger than normal so blood flows through more slowly, under less pressure and can come directly into contact with cells outside of the sinusoidal wall.
Gas exchange is faster.
This is useful in the liver, bone marrow, etc
What can poor capillary refill time suggest?
Suggests poor perfusion or dehydration
What are the function of valves in veins and how are structured?
Prevent the back flow of blood
Formed by a fold of tunica intima and strengthen by connective tissue
Semi lunar in shape with the concavity towards the heart
Abundant in the lower limbs where they must travel a long way against gravity.
