Lesson Overview 27.3 Circulation
Open and Closed Circulatory Systems <ul><ul><li>How do open and closed circulatory systems compare? </li></ul></ul>
Open and Closed Circulatory Systems <ul><ul><li>Many animals move blood through their bodies using one or more hearts.  </...
Open Circulatory Systems  <ul><ul><li>In an  open circulatory system,  blood is only partially contained within a system o...
Open Circulatory Systems  <ul><ul><li>One or more hearts or heartlike organs pump blood through vessels that empty into a ...
<ul><ul><li>In a  closed circulatory system,  blood circulates entirely within blood vessels that extend throughout the bo...
Closed Circulatory Systems  <ul><ul><li>Nutrients and oxygen reach body tissues by diffusing across thin walls of capillar...
Single- and Double-Loop Circulation <ul><ul><li>How do the patterns of circulation in vertebrates compare? </li></ul></ul>
Single-Loop Circulation  <ul><ul><li>Most vertebrates with gills have a single-loop circulatory system with a single pump ...
Single-Loop Circulation  <ul><ul><li>The  atrium  receives blood from the body.  </li></ul></ul><ul><ul><li>The  ventricle...
Double-Loop Circulation  <ul><ul><li>Most vertebrates that use lungs for respiration have a double-loop, two-pump circulat...
Double-Loop Circulation  <ul><ul><li>The first loop, powered by one side of the heart, forces oxygen-poor blood from the h...
Mammalian Heart-Chamber Evolution  <ul><ul><li>Four-chambered hearts like those in modern mammals are actually two separat...
Upcoming SlideShare
Loading in …5
×

Chapter 27.3

8,146 views

Published on

Published in: Health & Medicine, Business
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
8,146
On SlideShare
0
From Embeds
0
Number of Embeds
3,285
Actions
Shares
0
Downloads
42
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Chapter 27.3

  1. 1. Lesson Overview 27.3 Circulation
  2. 2. Open and Closed Circulatory Systems <ul><ul><li>How do open and closed circulatory systems compare? </li></ul></ul>
  3. 3. Open and Closed Circulatory Systems <ul><ul><li>Many animals move blood through their bodies using one or more hearts. </li></ul></ul><ul><ul><li>A heart is a hollow, muscular organ that pumps blood around the body. </li></ul></ul><ul><ul><li>A heart can be part of either an open or a closed circulatory system. </li></ul></ul>
  4. 4. Open Circulatory Systems <ul><ul><li>In an open circulatory system, blood is only partially contained within a system of blood vessels as it travels through the body. </li></ul></ul><ul><ul><li>Arthropods and most mollusks have open circulatory systems. </li></ul></ul>
  5. 5. Open Circulatory Systems <ul><ul><li>One or more hearts or heartlike organs pump blood through vessels that empty into a system of sinuses, or spongy cavities, where blood comes into direct contact with body tissues. </li></ul></ul><ul><ul><li>Blood then collects in another set of sinuses and makes its way back to the heart. </li></ul></ul>
  6. 6. <ul><ul><li>In a closed circulatory system, blood circulates entirely within blood vessels that extend throughout the body. </li></ul></ul><ul><ul><li>Many larger, more active invertebrates, including annelids and some mollusks, and all vertebrates have closed circulatory systems. </li></ul></ul><ul><ul><li>A heart or heartlike organ forces blood through vessels. </li></ul></ul>Closed Circulatory Systems
  7. 7. Closed Circulatory Systems <ul><ul><li>Nutrients and oxygen reach body tissues by diffusing across thin walls of capillaries, the smallest blood vessels. </li></ul></ul><ul><ul><li>Blood that is completely contained within blood vessels can be pumped under higher pressure and circulated more efficiently than can blood in an open system. </li></ul></ul>
  8. 8. Single- and Double-Loop Circulation <ul><ul><li>How do the patterns of circulation in vertebrates compare? </li></ul></ul>
  9. 9. Single-Loop Circulation <ul><ul><li>Most vertebrates with gills have a single-loop circulatory system with a single pump that forces blood around the body in one direction. </li></ul></ul><ul><ul><li>In fishes, for example, the heart consists of two chambers: an atrium and a ventricle. </li></ul></ul>
  10. 10. Single-Loop Circulation <ul><ul><li>The atrium receives blood from the body. </li></ul></ul><ul><ul><li>The ventricle then pumps blood out of the heart and to the gills. </li></ul></ul><ul><ul><li>Oxygen-rich blood travels from the gills to the rest of the body. Oxygen-poor blood then returns to the atrium. </li></ul></ul>
  11. 11. Double-Loop Circulation <ul><ul><li>Most vertebrates that use lungs for respiration have a double-loop, two-pump circulatory system. </li></ul></ul><ul><ul><li>The first loop of the circulatory system is powered by one side of the heart and forces oxygen-poor blood from the heart to the lungs. </li></ul></ul>
  12. 12. Double-Loop Circulation <ul><ul><li>The first loop, powered by one side of the heart, forces oxygen-poor blood from the heart to the lungs. </li></ul></ul><ul><ul><li>After the blood picks up oxygen and drops off carbon dioxide in the lungs, it returns to the heart. </li></ul></ul><ul><ul><li>The other side of the heart pumps oxygen-rich blood through the second circulatory loop to the rest of the body. </li></ul></ul>
  13. 13. Mammalian Heart-Chamber Evolution <ul><ul><li>Four-chambered hearts like those in modern mammals are actually two separate pumps working next to one another. </li></ul></ul><ul><ul><li>During chordate evolution, partitions evolved that divided the original two chambers into four, transforming one pump into two parallel pumps. </li></ul></ul><ul><ul><li>The partitions also separated oxygen-rich blood from oxygen-poor blood. </li></ul></ul>

×