Circulatory System Flashcards
What’s an open circulatory system?
Blood circulated in a large open space out into cavities surrounding animal organs. Slow less efficient
What’s a closed circulatory system?
Flows blood in 1 direction only to organs and muscles, gas exchange happens. Quicker and more efficient.
Blood is fully enclosed within blood vessels at all times
Higher pressure than open systems
Larger conc gradients
More complex organisms with higher metabolism
How do circulatory systems work?
Arteries transport o2 blood at high pressure from heart.
Near organs cells these arteries branch into capillaries
Gas exchange occurs by diffusion
Capillaries join together and deoxygenated blood is transported back to the heart in veins.
What’s arteries structure and function?
Thick smooth muscular wall.
Folded endothelium, narrow lumen, smooth lining, collagen.
Maintain high pressure without damage
Elastic to accommodate high pressure/recoil to maintain low pressure - reduce friction to blood flow - avoids damage.
Structure and function of veins?
Thinner walls, presence of valves, large lumen.
Allow skeletal muscle movement and low heart pressure to draw blood to heart.
Ensures blood continues to flow to heart.
Blood flows back to heart under low pressure.
Structure and function of capillaries?
Thin walls (1cell thick) forms large network near all cells of a tissue. Narrow lumen, just large enough for 1 red blood cell. Reduces diffusion distance, high rate of diffusion. Increase surface area, higher rate of diffusion distance between red blood cells and tissue cells (o2 and co2)
Where’s the heart located and what does it contain?
Between 2 lungs and above the diaphragm. Enclosed by the pericardium. Pericardial fluid is secreted between them to aid movement. Pericardium protects heart from over expansion.
What are cardiac muscle cells?
Located in walks of heart, appear striated and are under ‘involuntary control’.
Walls of heart are made of cardiac muscle.
They’re only found in the heart.
What are the 2 types of valves and their function?
Tricuspid valve - 3 flaps
Bicuspid valve - 2 flaps
Collectively known and atrioventricular valves - prevent back flow of blood.
What are the valves in PA and A known as and what are their function?
Semilunar valves - shaped as half moons
They prevent back-flow of blood
Why do we need a circulatory system?
Mass transport to overcome limitations of diffusion in meeting the requirements of an organism.
What are the advantages of an open circulatory system?
Requires less energy for distribution
More suited to animals with a slower metabolism
What are the disadvantages of an open circulatory system?
Almost impossible to increase blood distribution
Heart causes blood to fill body cavities
What is a single circulatory system?
Blood goes through heart once ever circuit of the body
What’s a double circulatory system?
Heart with 3/4 chambers
Blood goes through heart twice for every circuit of the body
