Cardiovascular and Circulatory Systems Flashcards
What are the components of a circulatory system?
Fluid, which carries the transported cells and molecules; a pump to move the fluids; vessels to carry the fluid between the pump and the body;
Open circulatory systems consist of…
Hemolymph (blood + ISF) which moves through vessels into extracellular spaces; no distinction between blood and interstitial fluid
Closed circulatory systems consist of…
Blood is pumped from the heart through vessels which branch off as capillaries to supply the tissues and then returns to the heart; distinction between blood and interstitial fluid
What do gastrovascular cavities consist of?
Consist of water which passes through teh cavity, supplying the body with nutrients
What is the main disadvantage of open systems?
Cannot control blood flow/where the blood is supplied to; low rate of oxygen transfer
Why can insects maintain high metabolic rates?
Because there open circulatory systems are not involved in the transport of oxygen, just nutrients and waste
What are the functions of insect haemolymph?
Transports nutrients and waste products and immune molecules; hemolymph cells involved in wound repair and immune response; hydraulic skeleton–>especially in larvae; heat transfer; important CO2 sink
Why does the left side of teh pumonary system have such high pressure?
Helps to force blood into capillaries
What is the difference between pulmonary and systemic circulation?
Pulmonary is low resistance, low pressure and systemic is high pressure so that flow can be selective to the organs and tissues; crucial for fight or flight
Fluid transfer across capillaries depends on what?
Hydrostatic pressure and osmotic forces (starling forces)
Low pressure in dorsal aorta limits selectivity of blood flow
ye
What is teh advantage of having a parallel circulation?
Cardiac output (ml/min) can be different between pulmocutaneous and system systems; adapted to period breathing–blood diverted to lung while breathing and away during no-breathing (to the skin?)
what is the disadvantage of parallel circulation?
single ventricle produces relatively low blood pressure
Arteries
Thick walls which are elastic
• When heart contracts, these arteries expand
• Thick wall makes them want to go back to original size
○ This wanting to go back helps to keep pressure up in circulatory system
Blood moves very fast in aorta but slowly through the capillaries
• Important because blood needs to move slowly since a lot of nutrient diffusion happens in capillaries
What is the role of artiers?
Carry blood away from the heart to the tissues
What is the role of arterioles
Deliver blood to the capillaries
Role of capillaries
Deliver blood and nutrients to the tissue
Venules
collect blood from teh capillaries
Vein
return blood to the heart
as diameter gets smaller, velocity becomes slower due to increase resistance
ye
What is the capillary wall composed of?
Single layer of entothelial cells–used for uptake of nutrients
How is blood returned to the heart through venous system?
aided by the use of muscle pumps, which push blood through valves and vlaves behind are closed to present back flow
The lymphatic system is a key component of the immune system; it collects interstitial fluid which becomes lymph and returns it to the venous blood
ye
What are the tissues and organs that compose the lymphatic system?
Lymph nodes, spleen, thymus, tonsils
What is the purpose of the lymphatic system?
To remove viruses, bacteria, damaged cells, and cellular debris from lymph and blood stream; also to defend the body against infection and cancer
What;s the main driving force of blood flow?
Mean arterial Pressure
What is the equation for resistance
R=8nuL/pi*r^4
