Download Note for circulatory - Raleigh Charter High School

Circulatory system notes
I.
Open vs. closed
a. Open
i. Hemolymph (body fluid) is pumped by heart
ii. Arthropods and mollusks
iii. Bathes internal organs directly
b. Closed
i. Contained in vessels
ii. Earthworm, squid and octopus, vertebrates
iii. Exchange between blood and interstitial fluid that bathes cells
II.
Vessels
a. Vein
i. To the heart
ii. Oxygen poor except in pulmonary circuit and in fetus
iii. Valves to stop backflow as pressure is low
iv. Thinner wall than artery
b. Artery
i. Away from the heart
ii. Oxygen rich except in pulmonary circuit and in fetus
iii. Thicker wall as it is under higher velocity and pressure than veins
c. Capillaries
i. Very small places of exchange and thin walled
ii. Connect arteries and veins
iii. More surface area, slow flow and tight fit lead to better exchange
iv. Most blood at any one time is in the capillaries
III.
Blood pressure
a. Taken by sphygmomanometer (cuff)
b. Systolic: when blood can squeeze through closed artery when ventricles contract
c. Diastolic: when blood flow can squeeze through closed artery even when ventricles are relaxed
d. Detected by sounds produced by blood flow using stethoscope
e. Systolic/Diastolic
120/75 = “normal” for your age
f. Hypertension is high blood pressure: What caused it is the question?
IV.
EKG
a. SA node generates a nerve impulse
b. Atria contract
c. AV node captures impulse and sends it to the Purkinje fibers on the other side of the septum (into
ventricle) by using the Bundle of His.
d. Ventricles contract after this delay
e. Heart readies itself electrically for the next impulse
V.
Countercurrent exchange
a. Blood flowing in opposite directions to maximize exchange
b. Gills of fish
c. Legs of arctic mammals (wolves)
d. Dolphin fins