The Heart & Blood Vessels (chpt. 26) Flashcards
Open circulatory system
Blood leaves blood vessels and flows around the cells before re-entering blood vessels
Closed circulatory system
Blood remains in a continuous system of blood vessels
What type of circulatory system do humans have
Double closed circulatory system
- pulmonary system
- systemic system
Advantages of a closed circulatory system
Blood can be pumped faster
Flow of blood can be increased / decreased
Advantages of double circulatory system
- separates oxygenated and deoxygenated blood
- endures blood pressure is high enough to reach all parts of body
- allows for rapid and efficient delivery of nutrients
Portal system
A blood supply that flows from one organ directly to another without passing through the heart
3 types of blood vessels
Arteries
Veins
Capillaries
Arteries
- carry blood AWAY from heart
- thick wall of muscle & elastic fibres
- no valves
- carry oxygenated blood
- rapid blood flow under pressure
- blood flows in pulses
Veins
- carry blood TO heart
- thin wall of muscle & elastic fibres
- valves prevent the back flow of blood
- carry deoxygenated blood
- slow blood flow under low pressure
- blood flows steadily
Capillaries
- wall is only 1 cell thick
- extremely narrow lumen
- no valves
- link arteries and veins
- carry oxygenated and deoxygenated blood
- slow blood flow
Where is the heart located
In the thoracic cavity, between the lungs, slightly to the left, above diaphragm and behind sternum
Pericardium
A tough protective sac surrounding the heart
Double membrane is filled with fluid to allow friction free movement
What muscle is found in the heart
Cardiac muscle - never tires
What’s special about cardiac muscle
If never tires
What makes up the hearts blood supply
Coronary arteries & coronary veins
