Chapter 28

Chapter 28 - NOTES FOR BIOLOGY 1002 SECTIONS 001 and 002...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
NOTES FOR BIOLOGY 1002 SECTIONS 001 and 002 Spring 2008 DR. STEVEN POMARICO Outline 4B CHAPTER 28 Circulation The need for circulation (and circulatory systems) arose, as animals got larger. Small (and thin) animals have all of their cells in close proximity to the outside environment. This means there is a very short distance that food and oxygen have to travel to get to the center of each cell. Likewise, the distance that waste and CO 2 have to travel to get out of the cell is also very short. Materials (good or bad) can efficiently move over short distance in an organism by diffusion. Larger distances require some energy requiring process (active transport, circulation, etc.). In larger animals since diffusion is not effective enough to get the good things (nutrients and oxygen) in and get the bad things (waste and carbon dioxide) out, circulation is required . There are two types of circulatory systems (see fig 28-1): Open circulatory system Closed circulatory system Both types have three major parts: 1) A fluid that circulates (blood) 2) A channel (vessels) that the fluid circulates through 3) A pump (heart) to keep the fluid moving
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
through is an open space within the body called the hemocoel (blood cavity) (see fig 28-1a) In the closed circulatory system the blood is usually confined (closed) in the vessels. THE VERTEBRATE CIRCULATORY SYSTEM In vertebrates, the circulatory system has seven major functions. The first three (that I’ve already mentioned) are common to all circulatory systems. 1) Transport of oxygen to the tissues 2) Transport of nutrients to the tissues 3) Transport of waste from the tissues Some of the next four are found only in vertebrates: 4) Distribution of hormones 5) Regulation of body temperature (homeostasis) 6) Prevention of blood loss (clotting) 7) Protection from invaders (immune system) The vertebrate heart is a muscular pump that has evolved in design over time (see fig 28-2) EVOLUTIONARY TREND IN HEART DESIGN Heart design Organisms 2-chambered heart fish 3-chambered heart amphibians and reptiles 4-chambered heart birds and mammals In all of these designs the heart chambers are either receiving blood ( atrium , plural atria ) from the body or sending the blood out ( ventricle ) into the body. THE FOUR-CHAMBERED HEART (see figs 28-3) In the four-chambered heart, one pair (right ventricle + left atrium) of chambers is used for pulmonary circulation . This part of the circulatory system is responsible for pumping blood to and
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 9

Chapter 28 - NOTES FOR BIOLOGY 1002 SECTIONS 001 and 002...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online