Circulatory Systems

How is oxygen transported to systemic tissues?

Bulk flow via circulatory system

• insects / some aquatic animals are exceptions

What are the components of the the circulatory system?

• Muscular pump

• Fluid

• Vessels

What are the functions of the circulatory system?

To transport:

• Oxygen, CO2

• Nutrients from digestive tract

• Waste from metabolism

• Hormones

• WBCs

• Stem cells → other tissues

What the difference between an open and close circulatory system?

Closed is completely closed, while open has a blood dumping area like a hemocoel

What happens to animals without a circulatory system?

They rely on simple diffusion through thin membranes for oxygen

• examples:

  • aquatic, invertebrates

Closed Circulatory system

• High blood pressures drive flow of fluid

  • arteries vs. veins

    • examples:

      • vertebrates

      • cephalopod mollusks

      • annelids

What controls vessel dilation?

The autonomic nervous system, (ANS)

• Constriction - reduces blood flow

• Dilation - increases blood flow

allows changing of lumen size allowing blood flow to specific structures to be control

How do byproducts leave the blood?

Through vessel walls: Capillaries

• only in endothelium/basal lamina

• 60-80 micrometers from most cells

• change amount of blood supply depending on tissue use

What is blood composition?

4-6 liters

• RBCs

• WBCs

• Platelets

• other respiratory pigments

What is found within blood plasma?

• Water

• Proteins

• Nutrients

• Electrolytes

• Waste

• Hormones

• Gases

What is hemoglobin?

A tetramer that has 4 globin chains with an iron molecule in the center

• binds with 1 O2 molecule

• can bind 4 O2 molecules total

other molecules can bind to O2 binding site and cause problems

What is oxygen unloading?

Hemoglobin releasing more O2 around tissues that have a lower partial pressure

• indicating a higher metabolic rate

as metabolic demands increase so does oxygen usage

What is required for a beating heart?

• Heart

• Myocardium - muscle tissue of the heart

• Cardiac output - volume of blood pumped per minute

• Stroke volume - volume of blood pumped per beat

multi chambered / myogenic in vertebrates

What connects systemic and breathing circuits?

Connected via a series

• one following the other

• most efficient at delivering oxygen