Lesson 8: Circulation and The Heart Flashcards
what is the function of a circulatory system?
It transports many essential materials around the body
what essential materials does the circulatory system transport around the body?
- oxygen from the respiratory system
- nutrients from the digestive system
- hormones from the endocrine system
- chemicals and cells from the immune system (ex: T-cells, B-cells, macrophages)
- metabolic wastes from the cells to the lungs and kidneys
- thermal energy (keeps the body temp regulated)
how did circulation evolve over time?
circulation became a “need” later in the evolutionary timeline as organisms increased in size and cells were no longer in contact with the environment
- it wasn’t always something we saw in primitive organisms that first existed; because organisms grew and got larger in size and complexibility, circulation became more necessary to have
what does the circulatory system allow for?
allows for oxygen and nutrients to be delivered to every cell in the body; also allows for wastes in the cells to be removed from the body (brings nutrients to where it needs to go but gets waste products out as well)
what are key features that a circulatory system needs to be considered one?
- fluid that transports or circulates materials throughout the body (for humans it is blood)
- a network of tubes in which the fluid circulates (blood vessels)
- a pump that pushes the fluid through the tubes (the heart *beats and pushes fluids through different parts of the body)
what are the different types of circulatory systems in organisms?
- none!
- open
- closed
types of circulatory systems: none- describe this system and how it works + who has it
not all living things required or even have a circulatory system!
- unicellular organisms like some bacteria, algae, and fungi can function without a circulatory system (because they directly exchange gases with the environment)
- some simple multicellular organisms do not require a circulatory system either, but instead depend on an internal body cavity lining covered in flagella to circulate fluid through the body
what is flagella and what is it for?
microscopic hair like structures that help with locomotion (they move things around) –> this is essentially what simple organisms use as a circulatory system
types of circulatory systems: open- describe what it is and how it works + who uses it
in an open circulatory system, the circulating fluid is pumped into a connected system of body cavities (often called sinuses)
- these openings bathe the cells directly in the hemolymph, which is a mixture of blood fluid and tissue fluid (all of their fluids are mixed together into one fluid, and this fluid gets pushed through body cavities)
- the contraction of one or more hearts forces this hemolymph around the body
*most invertebrates like snails or insects have this system
are open circulatory systems efficient or inefficient? why?
who is this system practical for and why?
this is relatively inefficient as the hemolymph is under low pressure and circulates slowly
- takes a long time for nutrients and things to get to where they need to go
HOWEVER, it is practical for many animals with low metabolic rates which therefore have lower oxygen and energy demands
types of circulatory systems: closed- what is it, how does it work, and who has it?
in a closed circulatory system, the fluid (often blood), is contained within a network of tubes called blood vessels
- what makes this system “closed” is that the blood in our bodies are not flowing freely- it is contained in blood vessels
- the blood and tissue fluid in our bodies are SEPERATE and do not mix (unlike in open systems)
all vertebrates and some complex invertebrates have a closed system
- there is a lot of variation in the structure of closed circulatory systems
- for instance, human circulatory systems differs from a fishes circulatory system, though we are both vertebrates
closed circulatory systems include complex “heart” structures depending on their evolution: this can be…
aortic arch, two chambered heart, three chambered heart, four chambered heart
what is the aortic arch? who is it found in?
type of closed circulatory system with enlarged blood vessels that work like hearts to pump blood through the system (found in earthworms)
what is the two chambered heart? who is it found in?
this structure is commonly found in fish; one atrium and one ventricle
what is the three chambered heart? who is it found in?
this structure is commonly found in amphibians; right and left atrium and then one ventricle
what is the four chambered heart? who has it?
this structure is found in reptiles, mammals, and birds; animals that have this system can or can not have a septum
- consists of a left and right ventricle and a left and right atrium
what is a septum? what does it do?
the septum divides the heart into two sides; septums seperate deoxygenated blood to oxygenated
what is the two-circuit circulatory system?
in these systems, the circulation of blood to the lungs (pulmonary circuit) is seperate from the circulation of blood to the rest of the body (systemic circuit)
what is the pulmonary circuit?
the part of the circulatory system that delivers blood to the lungs
what is the systemic circuit?
the part of the circulatory system that delivers blood around the body
what is the heart? where is it located? what is it made up of and what does each part do?
the heart is a muscular organ found in the middle of the chest, directly under the breastbone (it is the center and most important part of your circulatory system)
- the heart has two atria, which RECEIVE BLOOD FROM YOUR BODY at the TOP of the heart (both atrias are responsible for receiving from the top of the heart)
- the heart has two ventricles, which RECEIVE BLOOD FROM YOUR ATRIA at the BOTTOM of the heart (they reside at the bottom of the heart)
feature difference(s) between ventricles and atria
ventricular walls are much thicker and more muscular than the atria; this is because the ventricles have to pump blood a much longer distance
- ventricles are responsible for pumping blood to the rest of the body, which is a really long distance; on the other hand, atria pumps blood to the ventricles, which is really close in comparison (thus, they have less muscle)
what does the right side of the heart do? what does the left side do?
- right side: receives blood from your systemic circuit (body) and circulates blood to your pulmonary circuit (lung)
left side: receives blood from the pulmonary circuit (lungs) and circulates blood to the systemic circuit (body)
where does blood enter from in the heart?
blood enters your right atrium from one of two blood vessels
- blood from your upper body tissues enters from your superior vena cava
OR
- blood from your lower body tissues enter from your inferior vena cava
*SUPERIOR ON TOP INFERIOR ON BOTTOM
once blood enters the right atrium, what happens? what is the process like?
- once blood enters, your right atrium beats and contracts, which forces blood to enter the right ventricle THROUGH THE ATRIOVENTRICULAR VALVE (specifically the tricuspid valve)
- then, blood leaves your right ventricle through the semilunar valves (specifically the pulmonary semilunar valve) to go towards your lungs via your left pulmonary arteries
–> blood essentially exits the heart through the left pulmonary artery and into the lungs
what helps the valves in the heart to prevent backflow of blood?
the valves are supported by tough cords called CHORDAE TENDINEAE, which prevents blood from flowing backwards
what happens after blood exits the right ventricle and into the lungs? what is the process like?
- blood is oxygenated in the lungs and returns to the heart via the right pulmonary veins
- it then enters the left atrium, and is pushed (by contraction) towards the left ventricle through the MITRAL VALVE (the other atrioventricular valve)
- now that blood is in the ventricle, it has to get pushed out. It is pushed through the semilunar valve (specifically the aortic semilunar valve) and enters the aorta so it can be distributed through the body
what are the different types of valves in the heart and how do they differ?
in general, there are valves called the atrioventricular valves. these valves are between the atrium and ventricles
- there is the TRICUSPID valve, which is located on the right side of the heart between the right atrium and right ventricle
- there is the MITRAL valve, which is located on the left side of the heart, between the left atrium and left ventricle
there are also valves called the semilunar valves, which are located between the ventricles and arteries.
- there is the pulmonary semilunar valve (between right ventricle and left artery)
- there is the aortic semilunar valve (between left ventricle and aorta)
what are the coronary blood vessels? what do they do?
supply of blood vessels which branch off the aorta; it supplies blood to the heart and allows for contraction of the heart and circulation of the blood throughout the body
what is the pericardium? what does it do?
the pericardium is a double layer membrane that protects the heart
- it prevents friction from damaging the tissues in the heart, and keeps the heart lubricated (it is filled with fluid that allows for this)
systemic circuits carries ____ blood from ___ to ___
systemic circuits carries oxygenated blood from heart to all body tissues (high o2 low co2)
pulmonary circuits carries ____ blood from the ___ to the ___
pulmonary circuits carries deoxygenated blood from the heart to the lungs (low o2, high co2)
difference between arteries, capillaries, and veins?
arteries carry blood away from the heart, capillaries are small vessels that carry blood to body cells, and veins carry blood back to the heart
