Circulation and Gas exchange Lecture 24

Question 1

What is the function of the circulatory system

Answer 1

to transport fluids around the body

Question 2

What are the three components of a circulatory system?

Answer 2

Circulatory fluid (hemolymph in open; blood in closed)
Set of tubes through which fluids move (vessels)
Pump (heart) powers movement of fluid (circulation)

Question 3

What are two major differences between open and closed circulatory systems?

Answer 3

Open: found in insects, arthropods, and most molluscs.
Not used to transport oxygen and carbon dioxide
Has hemolymph
Closed: found in earthwormd, cephalopod molluscs. The circulatory system is referred to as cardiovascular system
Contains blood

Question 4

What is one advantage of an open circulatory system? What is one disadvantage?

Answer 4

Adv: requires less energy to use and maintain
Disadv: less efficient transport
No means of regulating flow of hemolymph to different organs

Question 5

What is one advantage of a closed circulatory system? What is a disadvantage?

Answer 5

Adv. more efficient transport of gases and nutrients
Distribution of blood can be altered
Disadv. more energetically expensive to use and maintain

Question 6

Compare heart structure and blood flow in fish, amphibians, reptiles and mammals/birds

Answer 6

Fish: Ventricle - gill capillary bed (gas exchange) - systemic circulation (tissue capillary beds) - atrium
Amphibians: Ventricle - forked vessel - lung/skin capillary beds - left atrium - ventricle - systemic circulation - right atrium
Mammals and birds: four chambered heart with atria and two ventricle, no mixing of oxygen rich and poor bloodS

Question 7

What are two physiological advantages of separate respiratory (pulmocutaneous or
pulmonary) and systemic circuits over a single circuit as seen in fishes, which combines gill and systemic circulation?

Answer 7

Systematic circuit: take oxygenated blood from the heart to the body tissue