Circulation and Gas Exchange

Question 1

Percentage of animals that use open circulation

Answer 1

80%

Question 2

Closed circulation systems…

Answer 2

-can pump blood under
pressure
– Faster delivery of oxygen
* But insects don’t use circulatory system to transport
O2
– Advantages of closed system greater with
increasing size

Question 3

Open circulation in humans

Answer 3

Lymphatic system
-Thymus
-Spleen
-lymph nodes

Question 4

Evolution of vertebrate heart and circulation
(fish)

Answer 4

• Two chambered heart
• Single circuit
• Two capillary beds
  – Oxygenated blood
  under low pressure

Question 5

Evolution of vertebrate heart and circulation
(amphibians)

Answer 5

• Three-chambered heart
• Two circuits
  – Pulmocutaneous circuit
• Gas exchange
  – Systemic circuit
• Delivery to body tissues
• Not completely separated
  – Some mixing of oxygenated
  and de-oxygenated blood

Question 6

Evolution of vertebrate heart and circulation
(mammals)

Answer 6

• Four-chambered heart
• Two circuits
  – Pulmonary circuit
• Gas exchange
  – Systemic circuit
• Delivery to body tissues
• Completely separated
  – More efficient oxygen
  delivery
  – Found in endothermic
  vertebrates (convergent)

Question 7

advantages of single circulation

Answer 7

works well under water

Question 8

advantages of double type circulation (amphibians)

Answer 8

can shut off lung circulation when under water (switch between single and double)

Question 9

Gills in aquatic animals

Answer 9

Gills are outfoldings of body, create large surface area for gas exchange

Question 10

Fish gills use a ____ system where blood flows in the ______ direction to water passing over the gills

Answer 10

Fish gills use a countercurrent exchange
system, where blood flows in the opposite
direction to water passing over the gills.

Question 11

Insect Tracheal system

Answer 11

• Network of branching tubes throughout the body.
• The tracheal tubes supply O2 directly to body cells.
• Circulatory system not involved in gas exchange
• Some insects use flight muscle to pump air into their
  tracheal system to meet O2 demands.

Question 12

Bird breathing…

Answer 12

air sacs require two cycles of inhalation and exhalation,=

air passes in one direction making ventilation highly efficient

Question 13

Avian respiration

Answer 13

no residual volume in lungs

no mixing of stale and atmospheric air

nearly 100% of atmospheric air enters blood

Question 14

Antarctic Icefish

Answer 14

• Lack hemoglobin
  – α globin gene present, but mutation stops
  expression
  – β globin gene lost

Question 15

How do Antarctic icefish get oxygen to cells?

Answer 15

– Cutaneous respiration (exchaning o2 through skin)
– Oxygen dissolved directly in blood