Lecture 9

Question 1

Unicellular organisms and some multicellular organisms lack circulatory systems and instead rely on

Answer 1

Passive diffusion to transport molecules from place to place

Question 2

Nematodes move fluid through their body cavities by

Answer 2

Contracting muscles in their body walls and relying on passive diffusion

Question 3

List the Solutions to Problem of Slow Diffusion in Large Animals:

Answer 3

• Specialized cells to transport fluid

- Circulatory Systems

Question 4

Sponges lack a circulatory system but move fluid around through

Answer 4

Bodies via specialized cells called choanocytes that have a flagella

Question 5

Circulatory Systems are found in

Answer 5

Large animals

Question 6

Animal Circulatory Systems have three main components:

Answer 6

• Pump
• Fluid
• System

Question 7

Fairy shrimp hearts have

Answer 7

Ostia

Question 8

Describe Ostia:

Answer 8

• Open when the heart is not contracted, allowing hemolymph to flow from a sinus back into the heart
• Opened with the help of suspensory ligaments that pull ostia open when the heart relaxes
• Close during contraction so hemolymph is sent through the vessels

Question 9

Closed Circulatory Systems have which 2 advantages?

Answer 9

• High Pressure + Flow Rates

- Ability to Control and Direct Blood Flow to Specific Locations

Question 10

Annelids have closed circulatory systems because they

Answer 10

Offer an advantage for organisms living in low oxygen environments

Question 11

Describe the Bony Fish Circulatory System:

Answer 11

• Bony fish hearts have four chambers arranged in a series

- Pumped blood flows to the gills and the rest of the body in a single loop / single circuit

Question 12

All the other vertebrate groups besides fish have two circuits:

Answer 12

• Pulmonary

- Systemic