The Heart And Blood Vessels Flashcards
(60 cards)
What is an open circulatory system?
Where the heart pumps blood into vessels that are open-ended. E.g spiders
What is an open circulatory system?
Where the heart pumps blood into vessels that are open-ended. E.g spiders
What is an open circulatory system?
Where the heart pumps blood into vessels that are open-ended. E.g spiders
Is a closed system or an open system more efficient?
A closed system is more efficient
Why is a closed circulatory system better than an open one?
- Blood can be pumped around the body faster, allowing the animal to be more active
- It allows the flow of blood to different organs to be increased or decreased
What is the composition of a closed circulatory system in humans?
- Blood
- Blood vessels
- The heart
What are arteries?
Arteries carry blood away from the heart. Arteries divide into smaller vessels called arterioles
What are veins?
Veins carry blood to the heart. Small veins are called venules
What are capillaries?
Capillaries are tiny vessels that link arteries and veins
What is the outer layer of veins and arteries?
Inelastic protein (collagen) which prevents the walls from over expansion
What is the outer layer of veins and arteries?
Inelastic protein (collagen) which prevents the walls from over expansion
What is the middle layer of veins and arteries?
Muscle and elastic fibres. The muscle is involuntary and can alter the size of the vessel. The elastic fibres bring the vessel back to shape when the muscle relaxes. The recoil of the artery also helps to pump blood.
What is blood pressure?
The force the blood exerts against the wall of a blood vessel
When is blood pressure the highest?
When the heart contracts
How can a pulse be detected?
By the expansion of the artery
What is the purpose of valves?
Valves help control the direction of blood flow
What adaptation do capillaries have?
Capillary walls are permeable so they allow exchange of materials between the blood and body tissues (diffusion)
What is the heart made of?
Cardiac muscle
What is the pericardium?
A double membrane surrounding the heart
What does pericardial fluid do?
Helps to reduce friction when the heart beats
How is cardiac muscle suitable for its role?
Cardiac muscle is slow to fatigue
What is the septum?
A wall that divides the heart in two sides
What do the atria do?
Pump blood to the lower chambers or ventricles.
Do atria have thick or thin walls?
Thin walls