The Cardiovascular System Flashcards
Order in which blood flows through heart
Vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta, body
Which side of the heart is thicker and why?
the left because it has to pump blood to the entire body so it has to work against a much higher pressure
What is the function of the arteries?
To carry oxygenated blood away from the heart
What is the function of the veins?
Carry oxygenated blood back to the heart
What is the function of the atrioventricular valves?
To prevent the back flow of blood from the ventricles to the atria.
Why is the left ventricle thicker than the right?
The left ventricle needs to contract harder to pump more blood further around the body and therefore requires more muscle (Right only pumps blood to lungs).
What is the function of the heart cords?
To prevent atrioventricular valves from turning inside out and to ensure the unidirectional flow of blood.
What is the function of the semi lunar valves?
To prevent the back flow of blood that has been pumped out of the heart from going into the ventricles
Describe the structure of arteries
Narrow lumen to maintain high blood pressure, thick layer of smooth muscle (contract and relax to dilate and constrict blood vessels - controlling their diameter) with elastic fibres (stretch and recoil), smooth inner endothelial lining, lots of collagen fibres.
Describe the structure of veins
Large lumen to minimise resistance to flow, thinner layer of muscle and elastic fibres, reduced collagen fibres, valves to prevent back flow of blood.
Describe the structure of capillaries
Very small, narrow lumen, thin endothelial tissue (one cell thick to maintain a short diffusion distance between cells).
What are the vessels entering the heart?
superior/inferior vena cava, pulmonary veins
What are the vessels leaving the heart?
Aorta, pulmonary artery
What is the vessel entering the lungs?
Pulmonary artery
What is the vessel that leaves the lung?
Pulmonary vein
What is the function of the ciliated epithelial cells?
to move substances along surface of tissue
Symptoms of cystic fibrosis
- thick mucus build up in the lungs
- Wheeziness of breathing
- Salty tasting skin
- frequent respiratory infections
Problems with cf thicker mucus?
Harder for the cilia to move, bacteria thrive in mucus (lots of infections), stops air getting to alveoli which causes shortness of breath.
Cardiac cycle: atrial systole
The atria contract forcing the atrioventricular valves open and blood flows into the ventricles.
Cardiac cycle: ventricular systole
The ventricles contract which forces the atrioventricular valves shut and the semi lunar valves open, thus allowing blood to leave the left ventricle through the aorta and the right ventricle through the pulmonary artery.
Cardiac Cycle: cardiac diastole
The atria and ventricles relax and pressure inside the heart chambers decreases causing semilunar valves in the aorta and pulmonary arteries to close, preventing the back flow of blood.
Relate the structure of the atria to their function
They are thin walled and elastic so they can stretch when filled with blood.
Relate the structure of the ventricles to their function
They have thick muscular walls to pump blood under high pressure. The left ventricle is thicker than the right as it has to pump blood further (all around) the body.
Vena cava function
Brings deoxygenated blood from the body to the heart.
