Exam 4

Question 1

What is the job of the circulatory system?

Answer 1

The circulatory system connects the cells to the outside. It brings resources to the cell and carry waste away.

Question 2

What are the three main parts of the circulatory system?

Answer 2

The heart, circulatory fluid, vessels.

Question 3

Name the four chambers of the human heart?

Answer 3

Right ventricle, left atrium, left ventricle, right atrium.

Question 4

Describe three differences between closed and open circulatory systems. Mention one example of an
organism with an open circulatory system and one with closed circulatory system

Answer 4

1. In an open circulatory system the circulatory fluid is the hemolymph, while organisms with closed
   circulatory system have blood.
2. The circulatory fluid is in direct contact with organs in an open system, while in a closed system the
   circulatory fluid is in vessels (veins, arteries).
3. Open circulatory systems can use fluid as a hydrostatic skeleton, but closed circulatory systems are easier
   to regulate depending on the needs of the organisms.
   Open example: insects, mollusks.
   Closed example: humans, annelids.

Question 5

How is blood different from hemolymph?

Answer 5

Blood is the circulatory fluid in animals with a closed circulatory system. It is composed of plasma, red blood
cells, white blood cells and platelets.
Hemolymph is the circulatory fluid for animals with an open circulatory system. It does not have red blood
cells and hemoglobin, hence does not transport oxygen.

Question 6

Mature red blood cells do not have mitochondria; what process allows them to generate energy?

Answer 6

Through anaerobic oxidation of glucose (glycolysis).

Question 7

What structural feature of the small intestine makes it better suited for absorption of nutrients than the
stomach?

Answer 7

The small intestine has a larger surface area compared to the stomach, which is better for absorption, it has
microvilli which also contribute to increase in the surface area.

Question 8

8. How does human anatomy indicate that our primate ancestors were not strict vegetarians?

Answer 8

Vertebrate digestive systems display many evolutionary adaptations associated with diet. For example, the
assortment of teeth (dentition) generally correlates with diet. Also, many herbivores have fermentation
chambers where mutualistic microorganisms digest cellulose. In addition, herbivores usually have longer
alimentary canals than carnivores, reflecting the longer time needed to digest vegetation.

Question 9

9. In which digestive system organ does nearly all nutrient absorption occur?

Answer 9

small intestine

Question 10

After surgical removal of the gallbladder, a person might need to limit his or her dietary intake of:

Answer 10

Fat

Question 11

Fat digestion yields fatty acids and glycerol. Protein digestion yields amino acids. Both digestive
processes:

Answer 11

add a water molecule to break bonds

Question 12

In human populations of northern European origin, the disorder called
hemochromatosis causes excess iron uptake from food and affects one in 200 adults. Among individuals 15 to
50 years old, men are ten times as likely as women to suffer from iron overload. Taking into account this
range of ages, propose a hypothesis that explains this difference.

Answer 12

Menstruation protects women from iron overload, making men more susceptible to hemochromatosis.