Cardiovascular System - Lecture 2 Flashcards
What kind of circulation is insect circulation?
open circulation
What is the circulatory fluid called in insects?
hemolymph
What corresponds to the blood and interstitial fluid in vertebrates?
hemolymph
Why doesn’t the circulatory system of insects not transport oxygen unlike the circulatory system of vertebrates?
because it does not have hemoglobin (respiration is carried out by the tracheal system)
How does circulation move in insects?
from back to front due to the dorsal vessel made up of an aorta and thoracic bulbs (heart)
What is the heart part of insects made up of?
chambers all ending in a valve called ostiole
Where is the hemolymph pumped in insects?
ostiole
What kind of circulation do fish have?
closed, single-loop
How many heart chambers do fish have?
2
Where does blood arrive in fish?
through the veins into the atrium then into the ventricle
What allows the blood to be sent into the artery when it contracts in fish?
the ventricle
At what level is blood deoxygenated in fish?
the gill branches
What kind of circulation do amphibians and most reptilians have?
closed, double-loop circulation
How many chambers of the heart do amphibians and most reptiles have?
3
What are the 2 circulations called in amphibians and most reptilians?
- the small circulation or pulmonocutaneous circuit
- the large circulation or systemic circuit
How are the chambers of the heart divided in amphibians and most reptilians?
2 atria and a single ventricle
Where does the small circulation go towards after leaving the ventricle in amphibians and most reptilians?
the lungs and the skin (places where gas exchange takes place)
How is blood ejected into the systemic circulation in amphibians and most reptilians?
blood enriched in O2 returns to the left atrium then passes into the ventricle
Where does oxygen-depleted blood go in amphibians and most reptilians?
the right atrium then to the ventricle
How many chambers does a crocodile’s heart have?
4
How many aortas do crocodiles have?
2
What does the right aorta connect in crocodiles?
the left ventricle to the systemic circulation
What does the left aorta connect in crocodiles?
the right ventricle to the systemic circulation
What is the valve between the right ventricle and the pulmonary circulation called in crocodiles?
“gear-tooth valve”
What happens to the gear-tooth valve of crocodiles underwater?
it closes
What happens to the oxygen-poor blood from the right side of the heart in crocodiles when the gear-tooth valve closes?
it enters the left aorta (systemic circulation)
How many chambers does the mammalian heart have?
4
What kind of circulation is the right heart responsible for in mammalians?
pulmonary circulation
What kind of circulation is the left heart responsible for in mammalians?
systemic circulation
What kind of circulation is the mammalian heart?
closed, double-loop
Why is oxygenated blood separated from deoxygenated blood in mammalians?
to have a better supply of O2 to cells and tissues
What is blood volume equal to?
5L (75 mL/kg)
What is one unit of blood equal to?
450 mL
What is stroke volume equal to?
70 mL
What is the formula for stroke volume?
end-diastolic volume - end-systolic volume
What % of blood is the venous system?
61%
Why is the venous system compliant?
because it can change accordingly to the changes in volume
What % of blood is the arterial system?
18%
Why is the arterial system resistant?
because changes in volume increase resistance
What is venous return?
the flow of blood from the periphery back to the atrium, and it is equal to cardiac output
What is cardiac output?
the amount of blood the heart pumps in one minute and is equal to the heart rate multiplied by the stroke volume
What would be the stroke volume if the cardiac output is 5L/min and the HR is 70 bpm?
70 mL
What is blood flow?
the volume (V) of blood circulating per unit of time (T)
How can blood flow be expressed?
mL/min or L/min
What is the normalized blood flow?
mL/min/100 gm
Why do we have a lot of capillaries?
to slow things down
Why is flow = area x MEAN velocity?
because the velocity is not necessarily the same at every point in the cross section
What is the structural difference bewteen arteries and veins?
veins have a valve
What are the 4 advantages of branching networks?
✓ Cells are close to a capillary
✓ High total area of the wall of the capillaries
✓ Low blood flow velocity in the capillaries
✓ High total cross-sectional area
