The Circulatory Systen Flashcards
What is the circulatory system ?
•Network of organs and vessels
•Enables the flow of blood and transport of oxygen, carbon dioxide, nutrients and other molecules around the body.
What are the main components of blood?
•Red blood cells
•White blood cells
•Platelets
•Plasma
What is the function of red blood cells?
•Transport O2 from lungs to tissues.
•Transport CO2 from tissues to lungs.
How do red blood cells transport oxygen to body cells?
•At the lungs haemoglobin in RBCs binds reversibly with oxygen to form oxyhemoglobin.
•At the tissues oxyhemoglobin breaks down to form haemoglobin and oxygen which diffuses into cells.
How are red blood cells adapted to their functions?
•Biconcave disk gives large SA/V ratio, increasing the diffusion rate.
•Lack of nucleus, allowing more space for haemoglobin molecules (increasing oxygen carrying capacity of the cell).
•Small and flexible so they can squeeze through capillaries.
What is the function of white blood cells?
Provide immunological protection:
•Phagocytes engulf and destroy pathogens.
•Lymphocytes produce antibodies.
How are Phagocytes adapted to their function?
•Can change shape to engulf foreign material.
•Flexible membrane allows them to squeeze through pores in capillary walls and enter tissue fluid.
•Contain enzyme that digests pathogens.
What is the function of platelets?
Role in blood clotting.
What is plasma?
•Pale-yellow liquid portion of the blood
•Transports proteins, nutrients, waste products, hormones, antibodies, etc.
How is plasma adapted to its function?
It consists mainly of water which acts as a solvent, enabling the transport of materials around the body.
Describe the double circulatory in humans:
Blood flows through the heart twice in two circuits:
•Pulmonary circuit
•Systemic circuit
What is the pulmonary system?
•Involves right side of heart.
•Deoxygenated blood transported to lungs
•Gaseous exchange occurs between alveoli and capillaries
•oxygenated blood returns to left side of the heart
What is the systemic circuit?
•Involves left side of heart
•Oxygenated blood pumped to tissues and organs around the body
•exchange of materials occurs at tissues
•deoxygenated blood returns to right side of heart
Name the four chambers of the heart
•Left atrium
•Left ventricle
•Right atrium
•Right ventricle
Describe the pathway of blood around the body, naming the structures of the heart
Pulmonary vein—> left atrium —> left ventricle—> Aorta —>Body—> vena cava—> right atrium—> right ventricle—> pulmonary artery—> lungs
Why is the left ventricle thicker than the right ventricle?
•It pumps blood a further distance
•It must generate a greater force of contraction so blood can be pumped at a higher pressure.
What are the heart walls made out of?
Cardiac muscle
What is the function of the cardiac muscle?
Contracts to pump blood around the body
What is the function of the coronary arteries?
Supply heart muscle with oxygen and nutrients
What is the function of valves in the heart?
Prevent the back flow of blood
What are the two types of valves found in the heart?
•ArtioVentricylar valves
•Semi-lunar valves
Where are the atrioventricular valves located?
Between the atria and the ventricles
What are the two types of atrioventricular valve?
•Bicuspid valves
(Between left atrium and left ventricle)
•Tricuspid valves
(Between right atrium and right ventricle)
Where are the semi-lunar valves located?
Between the ventricles and the arteries
