1.1 - What is cardiovascular disease? Flashcards
Define single cellular organisms.
organisms that are made up of only one cell
Define multi cellular organisms.
organisms that are made up of more than one cell
Why don’t single cellular organisms need circulatory systems?
- lrgr SA:V ratio
- take in nutrients by dffsn
- as hve shrter dffsn dstncs
What is the main reason multi cellular organisms need circulatory systems?
- smllr SA:V ratio
- have mr cmplx srtcrs
- so hv lngr dffsn dstncs
Why does an increased level of activity lead to a need for circulatory systems?
High mtblc rate = needs lrg O2 supply
crcltry systms needed as dffsn dstncs for O2 = too far
What has a bigger SA:V ratio? Mouse or elephant?
mouse
What are the 2 types of circulatory systems?
- open
- closed
What is an open circulatory system?
consists of a heart that pumps a fluid around that is not enclosed in vessels
What is a closed circulatory system?
blood is fully enclosed within blood vessels at all times
Why do only small animals have an open system?
-do not have complex structures
-so fluids do not need to be enclosed in vessels
- & travel long dstncs & thus small animals can use diffusion
What are 2 advantages of a double circulatory system?
- blood can pass slowly through region of gaseous exchange maximising transfer of O2 & CO2
- blood flows at a higher pressure to body
What is an advantage of a closed circulatory system?
allows blood to flow @ higher pressures, so blood travels faster around body
What is a disadvantage of this 3 chambered system?
do not seperate oxygenated & deoxygenated blood - allows less effcnt trnsprt of O2 -> body cells
Which blood vessel has valves?
veins
Which 2 blood vessels carry oxygenated blood from the heart to the body cells?
arteries & arterioles
Which 2 blood vessels carry deoxygenated blood from the body cells to the heart?
veins & venules
What is the biggest artery in the body?
aorta
What 3 things are the artery walls made up of?
- elastin fibres
- smooth muscle
- colllagen
What is the function of elastin fibres?
made of elastin - allow arteries & veins to stretch & recoil providing vessel with flexibility
What is the function of smooth muscle?
contracts & relaxes changing size of lumen
What are the walls of veins made up of? What is the difference between the walls of veins & arteries?
- elastin fibres
- smooth muscle
- collagen
(all in smaller proportions to arteries= larger lumen)
Due to low blood pressure, what do veins not have?
pulse