Circulation Flashcards
Define Perfusion
the act of sending blood to a particular tissue (verts. don’t have enough blood to go to all capillaries at once)
Describe the blood flow from an arteriole to a venuole
arteriole -> sphincter -> capillary bed -> venuole
How do veins accommodate slow moving blood/How is the blood pushed upwards with such low pressure?
large diameter (larger than arteries) muscles around vein flex to increase pressure and send blood up (one-way valve prevents back flow)
Describe an open circulatory system
blood vessels empty directly into coelomic cavity
hemolymph instead of blood
Describe a closed circulatory system
blood remains inside vessels
Describe Single Circulation
heart -> gills -> capillaries -> heart
Describe Double CIrculation
heart -> lungs -> heart -> capillaries -> heart
The atria receives…
veinous blood
The ventricle receives…
blood from atria
What is a main function of the Ventricle?
greatly increases pressure to pump blood through pulmonary and systemic circulation
Describe 3 steps of contraction in the heart
- sino-atrial valve opens -> atrium exerts neg. pressure, fills w/ blood
- atrium contracts, increasing pressure -> pushes blood into ventricle
- ventricle contracts greatly increasing pressure -> pushes blood into ventral aorta
Describe the aortic arches of a Lamprey
7 aortic arches
all similar and pass gills where gas exchange takes place
Describe the aortic arches of Chondrichtyes
4 arches pass gills (3,4,5,6)
arch #1 passes by spiracle
arch #2 no longer serves a gill -> becomes Efferent Branchial artery (goes to brain/head)
Describe the aortic arches of Osteichthyes
similar to sharks (arch #2 modified to serve head)
except arch #1 is lost completely
Describe the aortic arches of Lungfish
aortic arch #1 lost
arch #2, 5, 6 serve gills
Describe lungfish aortic arches when breathing in water
valves on arch #3,4 shut
valve from arch #6 to lung is shut
Describe lungfish aortic arches when breathing in air
valves on arch #2,5,6 shut (no need to send blood to gills)
O2 poor blood goes up 6th arch into lungs
What structure helps to maintain separation of the two flows of blood in the Lungfish heart?
interventricular septum (keeps flow through 2 sides of ventricle separate)
Describe the aortic arches of larval Amphibians
arch #1,2 lost entirely
arch #3,4,5 serve gills
arch #6 serves [non-active] lung
Describe the aortic arches of adult Amphibians
arch #3 and ventral aorta serves corotid artery (to the head)
arch #4,5 go to dorsal aorta (to downstream of head)
arch #6 goes exclusively to lung
Describe the aortic arches of terrestrial vertebrates
similar to adult amphibians except arch #5 is lost (so only arch #4 serves the dorsal aorta)
