Circulation

Question 1

Define Perfusion

Answer 1

the act of sending blood to a particular tissue (verts. don’t have enough blood to go to all capillaries at once)

Question 2

Describe the blood flow from an arteriole to a venuole

Answer 2

arteriole -> sphincter -> capillary bed -> venuole

Question 3

How do veins accommodate slow moving blood/How is the blood pushed upwards with such low pressure?

Answer 3

large diameter (larger than arteries)
muscles around vein flex to increase pressure and send blood up (one-way valve prevents back flow)

Question 4

Describe an open circulatory system

Answer 4

blood vessels empty directly into coelomic cavity

hemolymph instead of blood

Question 5

Describe a closed circulatory system

Answer 5

blood remains inside vessels

Question 6

Describe Single Circulation

Answer 6

heart -> gills -> capillaries -> heart

Question 7

Describe Double CIrculation

Answer 7

heart -> lungs -> heart -> capillaries -> heart

Question 8

The atria receives…

Answer 8

veinous blood

Question 9

The ventricle receives…

Answer 9

blood from atria

Question 10

What is a main function of the Ventricle?

Answer 10

greatly increases pressure to pump blood through pulmonary and systemic circulation

Question 11

Describe 3 steps of contraction in the heart

Answer 11

1. sino-atrial valve opens -> atrium exerts neg. pressure, fills w/ blood
2. atrium contracts, increasing pressure -> pushes blood into ventricle
3. ventricle contracts greatly increasing pressure -> pushes blood into ventral aorta

Question 12

Describe the aortic arches of a Lamprey

Answer 12

7 aortic arches

all similar and pass gills where gas exchange takes place

Question 13

Describe the aortic arches of Chondrichtyes

Answer 13

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)

Question 14

Describe the aortic arches of Osteichthyes

Answer 14

similar to sharks (arch #2 modified to serve head)

except arch #1 is lost completely

Question 15

Describe the aortic arches of Lungfish

Answer 15

aortic arch #1 lost

arch #2, 5, 6 serve gills

Question 16

Describe lungfish aortic arches when breathing in water

Answer 16

valves on arch #3,4 shut

valve from arch #6 to lung is shut

Question 17

Describe lungfish aortic arches when breathing in air

Answer 17

valves on arch #2,5,6 shut (no need to send blood to gills)

O2 poor blood goes up 6th arch into lungs

Question 18

What structure helps to maintain separation of the two flows of blood in the Lungfish heart?

Answer 18

interventricular septum (keeps flow through 2 sides of ventricle separate)

Question 19

Describe the aortic arches of larval Amphibians

Answer 19

arch #1,2 lost entirely
arch #3,4,5 serve gills
arch #6 serves [non-active] lung

Question 20

Describe the aortic arches of adult Amphibians

Answer 20

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

Question 21

Describe the aortic arches of terrestrial vertebrates

Answer 21

similar to adult amphibians except arch #5 is lost (so only arch #4 serves the dorsal aorta)