Unit 8: Diversity of Life

Content Outline: Circulatory and Immune Systems (8.11)

  1. Circulatory System - Responsible for connecting all the cells of the whole organism.
  2. It distributes nutrients, oxygen, hormones, and functions in waste retrieval.
  1. Evolution of the Circulatory system:
  2. It started with a Gastrovascular Cavity. (As seen in Cnidarians and Platyhelminthes.)
  3. Open Circulatory system is one type that evolved. (Arthropods and some Mollusks)
  4. Bloodbathes the organsby moving through sinuses (spaces).
  5. The system has a tubular heart with directional arteries to distribute blood.
  6. Closed Circulatory system (Annelids, some mollusks, vertebrates)
  7. Blood is confined to traveling through blood vessels under pressure.
  8. A muscular chambered heartmostly (Not inannelids.)(2,3,4 chambers)
  9. Atriums – These chambers receive blood coming into the hear t.
  10. They are composed of a thin layer muscle tissue.
  11. Ventricles – These chambers pump blood away from the heart.
  12. They are composed of a thick layer of muscle tissue.
  13. Mammals, birds, reptiles, and amphibians have a Double loop system.
  14. One loop for getting oxygen; one loop for delivering oxygen.
  15. Water vascular system (Echinodermata) (Madreporite, Tube feet, canals are the parts.)

III. Blood Vessel types of the body:

A. Arteries – These are large blood vessels carrying blood away from the heart.

B. Arterioles – These are medium sized vessels carrying blood away from the heart.

C. Capillaries – These are the smallest blood vessels where nutrients and oxygen diffuse out.

D. Venules – These are small blood vessels that collect waste materials from the tissues.

E. Veins – These are large blood vessels that carry blood toward the heart.

  1. Blood distribution

A.During digestion of food – The blood mainly is in the digestive organs.

  1. Swimming? The blood is not in the muscles, which are needed to swim, so you cramp if you go swimming right after eating. So wait 30 minutes.

B.During Exercise – The blood is mostly in the muscles and skin; not the digestive organs.

  1. Types of Blood cells:

A.Erythrocytes - These are red blood cells-RBC’s (“erythro” means “red”; “cyte” means “cell”)

  1. Hemoglobin uses iron(Fe) to hold oxygen. (“heme” means “iron”)
  2. Each RBC can hold 1 billion oxygen molecules.

B.Leukocytes - These are white blood cells – WBC’s (“leuko” means “white”)

  1. They protect our bodies against invading organisms or materials.
  2. Some of these cells (B-Lymphocytes) make antibodies to help clean up your blood of pathogens (disease causing agents, such as bacteria and viruses.)
  3. Some of these cells (T-Killer Lymphocytes) kill infected cells.

C.Platelets – These are pieces of RBC’s used for making clots.

  1. Immunity

A.This term refers to our white blood cells being able to attack pathogens.

B.There are two types of immunity:

  1. Innate Immunity (A.K.A. General Immunity)
  2. These are defenses you are born with, such as skin, tears, mucus in your nose and ears.
  3. For plants, it is bark, thorns, spines on a cactus, bad tasting chemicals.
  4. Specific Immunity
  5. This uses the Lymphocytes to attack specific pathogens, such as Chicken Pox.
  6. This type of immunity is acquired (received by you) in two ways:
  7. Active immunity
  • You have to get and then fight the pathogen. (Chicken Pox is an example.)
  • You make memory cells to fight future infections. It takes less time to get better.
  1. Passive Immunity
  • You have to get a shot (immunization) to make the memory cells.
  • The shot contains weakened viruses, so you hopefully do not get sick.
  • Some immunizations only last a couple of months or years.