Unit 4: Animal
Lesson 9: Introduction to Circulatory System and Blood
Functions of a Circulatory System
 delivers vital nutrients (e.g., oxygen) to all body cells
 eliminates waste products and carbon dioxide
 transports chemical messengers (e.g., hormones) from one part of the body to another
 helps to maintain a constant body temperature (warm blooded animals)
Types of Circulatory Systems
Open Circulatory System – Hemolymph (mix of blood and tissue fluid) is pumped directly into the body cavity.
Closed Circulatory System – Blood is seperate from the rest of the body in a network of tubes.
Single-circuit circulatory system – Only one track the blood can travel
Two-circuit circulatory system - Circulation to the lungs is separated from circulation to the rest of the body.
pulmonary circuit:the part of the circulatory system that delivers blood to the lungs
systemic circuit:the part of the circulatory system that delivers blood around the body
Blood: What is in it?
 Human body contains 4L to 5L of blood depending on the size of the individual
 Blood is a connective tissue – a tissue that consists of cells suspended in an intercellular matrix
 Using a centrifuge, blood can be separated into its two components – plasma (less dense, rises to top) and cellular components (more dense, sinks to bottom)
Plasma:
 Protein-rich liquid; over 90% is water
 Oxygen, proteins, nutrients (glucose, minerals and vitamins), carbon dioxide and other waste products from cellular respiration are dissolved or suspended in plasma
 Blood proteins in plasma include; albumins, globulins, fibrogens o Albumins: helps regulate the amount of water within the body o Globulins: transports lipids, cholesterol, some fat-soluble vitamins, some minerals
 Immunglobins (or antibodies) help fight infectious diseases o
Fibrogens: play a critical role in blood clotting; plasma with fibrogen removed is called serum
 Plasma also carries a number of dissolved ions: Na + , K + , Ca 2+ , Cl - , HCO
3
. Na + and Cl are most common ions. When the concentration of Na + in the plasma is high, it creates an osmotic pressure gradient and causes water to enter the blood stream. As more water enters the blood, the total volume of blood increases and the blood pressure rises.
This explains why high salt diets lead to hypertension (high blood pressure)
Cellular Components:
 Red Blood Cells - For Transport o
(erythrocytes) carry oxygen from the lungs to the body cells and carry carbon dioxide from the body cells back to the lungs to be expelled o
Formed from stem cells in marrow of vertebrae, ribs, breastbone, skull and bones of the arms and legs

o Erythrocytes die after about 120 days ; then removed by the liver and spleen o Between 2million and 3 million erythrocytes are produced each second o When erythrocytes are developing in the marrow, they have a nucleus, but as they mature and are released into the blood stream, their nucleus breaks down and disappears.
 White Blood Cells – For Protection o (Leukocytes) are formed in bone marrow and always have a nuclei o first line of defense against harmful bacteria, viruses and other disease causing agents o
Several different types in two categories – granular and agranular
 Granular – have grains in their cytoplasm and attach foreign material and microorganisms
 Agranular – specialized for engulfing bacteria and microorganisms through phagocytosis. This involves engulfing the bacteria within the cell membrane and release enzymes to destroy the target and the leucocyte itself o Remnants of leuckocytes and whatever it engulfed are left behind in a whitish substance called pus
 Platelets – For Protection o For protection; involved in clotting or coagulation o Small cell fragments produced from stem cells in bone marrow o
When blood vessel is broken, chemicals in platelets cause the platelets to stick to collagen fibres in the blood vessel wall. As more and more platelets stick to the fibres, a clot is
Blood Types: created to seal the hole in the blood vessel o The permanent clot stops the leakage of blood and allows time for the injury to heal and then the blood clot is absorbed by the body.
Recall that the four blood types are: A, B, AB, O.
The Rhesus Factor:
The Rhesus factor is another inherited factor discovered by studying the blood of rhesus monkeys. The rhesus factor is an antigen on erythrocytes that produce an antibody reaction. This is not as severe as the antibody reaction to blood type markers. The rhesus factor is present in approximately 85% of the population deeming them Rh-positive. The remaining 15% do not have this factor and are considered Rh-negative. Rh-negative people can donate their blood to Rh-positive people, but they cannot receive Rh-positive blood.
QUESTIONS:
1. a) What are the two main functions of blood? b) Create a table or other graphic organizer to describe the components of blood and their functions.
2. How are erythrocytes different from other cells of the body?
3. Describe the process of blood clotting. What risk is associated with blood clotting?
4. Emergency vehicles may carry O-negative blood for use at the scene of an accident. Explain why this is a common practice?
5. Create a table or use a graphic organizer to summarize the compatibility of each ABO blood type and rhesus factor with other blood types.

SOLUTIONS:
Questions 3-5: