[Unit 3.4] Mass Transport Flashcards
Organisms exchange substances with their environment (13 cards)
why do some organisms need circulatory systems
- large size
- small SA:V
- metabolically / physically active
what are the 3 features of all circulatory systems
- pump for pressure
- fluid which substances are transported in
- exchange surfaces that allow substances to enter and leave
what are the two types of circulatory systems (two answers)
- single & double circulatory system
- open & closed circulatory system
what is an open circulatory system
- blood not in vessels
- tissues and cells bathed directly in “blood” (hemolymph)
- blood is pumped to head by peristalsis
- relying on gravity and muscle contraction
- blood enters through pores into the heart
- trachea delivers oxygen directly from environment
what is a closed circulatory system
- blood remains in vessels
- separate fluid bathes tissues and cells called tissue fluid
- closed systems have higher pressure
- so blood flows more quickly to deliver more oxygen and nutrients
- and removes oxygen and waste quicker
what is the role of the anterior / superior vena cava
receive deoxygenated blood from upper body
what is the role of the posterior / inferior vena cava
receive deoxygenated blood from the lower body
what is the general role of valves in the heart
prevent backflow of blood
ensure it only flows in one direction
close when pressure is higher behind the valve
what are the two types of valves in the heart
atrioventricular (AV)
semi-lunar (SL)
what is the role of the AV valves in the heart
connect atria to ventricle
stop backflow into atria when ventricles contract
what is the role of the SL valves in the heart
connect ventricles to pulmonary artery and aorta. stop backflow into heart when ventricles contract
what are the cords in the heart
tendons that attach AV valves to ventricles. stopping valves from being forced into atria when ventricles contract
what causes the “lub” (S1) and “dub” (S2) sound when the heart beats
- first louder sound (S1) is made when AV valves shut
- second sound (S2) is made by SL valves shutting
