Circulatory Systems Flashcards
What lacks a separate circulatory system?
- sponges
- cnidarians
- platyhelminthes
- nematodes
What body characteristics can make a circulatory system unecessary?
- use diffusion
- thin body walls
What do larger animals require?
a separate circulatory system for nutrient and waste transport
What is an open circulatory system?
no distinction between circulating and extracellular fluid
What is the fluid in open circulatory systems called?
hemolymph
What is a closed circulatory system?
distinct circulatory fluid enclosed in blood vessels and transported away from and back to heart
What types of circulatory system do fish have?
true chamber-pump heart
How many structures (?) do fish have in their circulatory system?
4
What do the 4 structures in the fish circulatory system form?
one after the other form 2 pumping chambers
What is the 1st pumping chamber of fish circulatory system made of?
sinus venosus and atrium
What is the 2nd pumping chamber of fish circulatory system made of?
ventricle and conus arterious
What kind of circuit system do fish have?
single circuit system
What is the pattern of blood flow for fish?
1st chamber -> 2nd chamber -> gills -> tissues ->start over again
What is the lateral side of single loop circulatory system?
gills to tissues
What is the venous side of single loop circulatory system?
tissues to heart
What do lungs in amphibians require?
double circulation, a second pumping circuit
What makes up double circulation?
- pulmonary circulation
- systemic circulation
What is pulmonary circulation?
moves blood between the heart and lungs
What is systemic circulation?
moves blood between the heart and rest of body
What do arteries do?
carry blood away from the heart
What do veins do?
carry blood to the heart
What kind of heart do amphibians have?
3 chambered heart (2 atria and 1 ventricle)
Does oxygenated blood and deoxygenated blood mix for amphibians?
somewhat
How do amphibians obtain additional oxygen?
cutaneous diffusion
What kind of heart do most reptiles (except crocodiles) have?
3 chambered heart
What do reptiles have in their heart?
a septum that subdivides the ventricle
What is the purpose of the ventricle being subdivided in reptiles?
reduces the mixing of blood in the heart
Which chamber of the heart does the most pumping?
ventricle
What prevents blood from moving backwards?
valves
What kind of heart do mammals, birds, and crocodilians have?
4 chambered heart (2 separate atria and 2 separate ventricles)
What are the 2 atria of a 4 chambered heart?
right and left
What is the function of the right atrium?
receives deoxygenated blood from the body and delivers it to the right ventricle, which pumps it to the lungs
What happens when deoxygenated blood goes through the lungs?
it becomes oxygenated
What is the function of the left atrium?
receives oxygenated blood from the lungs, delivers it to the left ventricle, which pumps to rest of body
Does blood mix for mammals, birds, and crocodillians?
no
What happens to valves as the heart goes through the cardiac cycle?
open and close through the cardiac cycle of diastole and systole
What is diastole?
rest, volume increases
What is systole?
contraction, volume decreases
What are the sounds heard under a microscope caused by?
valves of heart opening and closing
What are the aorta and its branches?
systemic arteries
What is the function of the systemic arteries?
carry oxygen-rich blood from the left ventricle to all parts of the body
What is the function of the coronary artieries?
supply the heart muscle itself
What is the function of the superior vena cava?
drains the upper body
What is the function of the inferior vena cava?
drains the lower body empty into the right atrium, completing the systemic circulation
How many pairs of valves does the heart have?
2
What are the 2 pairs of valves the heart has?
- atrioventricular (AV) valves
- Semilunar valves
What are the atrioventricular valves function?
guard the openings between atria and ventricles
What are the two Atrioventricular valves?
- tricuspid valve
- bicuspid (mitral) valve
On what side is the tricuspid valve?
right
On what side is the bicuspid (mitral) valve?
left
What is the function of the semilunar valves?
guard the exits from the ventricles to the arterial system
What are the two semilunar valves?
- pulmonary valve
- aortic valve
What side is the pulmonary valve on?
right
What side is the aortic valve on?
left
describe the mammalian circulatory system?
- superior vena cava brings deoxygenated blood into the right atrium
- tricuspid valve opens letting blood into right ventricle and then closes
- right ventricle contracts and pulmonary semilunar valve opens, letting blood into the pulmonary arteries, then closes
- pulmonary arteries carry the deoxygenated blood to the left and right lungs
- gas exchange occurs and now the blood carries oxygen
- pulmonary veins pump oxygenated blood from left and right lungs to the left atrium
- bicuspid valve opens and lets blood into left ventricle and then closes
- aortic valve opens and left ventricle contracts, and flows into aorta and closes
- aorta carries highly oxygenated blood to the tissues
Why are the walls of the left ventricle thicker than the right?
left ventricle is sending blood to the tissues of the body which is a farther distance and there is a lot of resistance from blood vessels
What is arterial blood pressure measured with?
sphygmomanometer
What are the two pressures the sphygmomanometer measures?
systolic and diastolic
What is systolic pressure?
the peak pressure at which ventricles are contracting
What is diastolic pressure?
the minimum pressure between heartbeats at which the ventricles are relaxed
What is blood pressure?
the ratio of systolic over diastolic pressure
What does blood pressure increase at?
systole
What can high blood pressure do?
weaken vessels, blow out capillaries in eye and cause blindness
What does blood leave the heart through?
arteries
What are the finest, microscopic branches of the arterial tree?
arterioles
What does blood from arterioles enter?
capillaries, act as a transition point between arteries and veins
What is blood collected into after capillaries?
venules
What larger vessels do venules lead to?
veins
What carries blood back to the heart?
veins
What blood vessel has the thinnest wall thickness?
capillaries, one cell thik
What tissue layers are arteries and veins composed of?
- endothelium
- elastic fibers
- smooth muscle
- connective tissue
What is the endothelium?
innermost layer of veins/arteries, has contact with the blood
What is the purpose of elastic fibers in veins/arteries?
connective tissue, stretch and allow blood vessel diameter to dilate or contract
What is the purpose of smooth muscle in veins/arteries?
cause expansion/contraction of blood vessel
What is connective tissue in veins/arteries?
outermost layer
What are capillaries composed of?
a single layer of endothelial cells (simple squamous)
What is the function of capillaries being a single layer of cells?
allows rapid exchange of gases and metabolites between blood and body cells
What is spread throughout the layers of veins/arteries?
nerve cells
What do veins in the lower extremities have?
valves
What is the purpose of valves in lower extremity veins?
prevent backflow of blood, and prevent blood from settling down in lower extremities
What are the 3 types of cappilaries?
- capillary
- fenestrated capillary
- sinusoid
How do red blood cells move through capillaries?
only large enough for red blood cells to move through one at a time
What is a fenestrated capillary?
has little holes, allows ? move at faster rate
What is a sinusoid?
larger holes in capillary, allows faster diffusion to take place
Where are sinusoids found? Why?
in brain because brain has high demand for oxygen
What is the contraction of the smooth muscle layer in arteries/arterioles called?
vasoconstriction
What is the purpose of vasoconstriction?
increase resistance and decrease blood flow, can redirect blood if damage somewhere in body
What can chronic vasoconstriction lead to?
hypertension
What is hypertension?
high blood pressure, leads to backpressure and possible heart damage
What is relaxation of the smooth muscle layer in arteries/arterioles?
vasodilation
What is the purpose of vasodilation?
decrease resistance and increase blood flow to organs; can be important for homeostasis such as temperature regulation (flushed cheeks)
How does smooth muscle compare in veins/venules to arteries?
thinner
What helps veins/venules return blood to the heart?
skeletal muscle contractions and one-way venous valves
