Cardiovascular System Flashcards Preview

ESA 1 - Body Logistics > Cardiovascular System > Flashcards

Flashcards in Cardiovascular System Deck (22):

What are the functions of the CVS?

1. Circulates and transports nutrients, O2, CO2, hormones and blood cells to and from the cells of the body.
2. Fights disease.
3. Helps maintain homeostasis (pH and temperature).


What are the 3 essential components of the CVS?

- Heart
- Blood
- Blood vessels


What are the 2 circulation components of of the CVS?

- Pulmonary circulation: 'loop' through lungs where blood is oxygenated.
- Systemic circulation: 'loop' through rest of body to provide oxygenated blood and receive deoxygenated blood.


Where in the CVS is blood found at any one time?

- Heart & lungs - 20% (1L)
- Peripheral arteries - 10% (0.5L)
- Capillaries - 5% (0.25L)
- Peripheral veins - 65% (3.25L)


How much blood does the average adult have and what is this composed of?

- 5L
- 2L erythrocytes, 3L plasma


Which side of the heart is stronger and why?

- Left side is more muscular and robust to deal with higher pressure.
- Right side is more fragile due to lower pressure.


Which vessels vascularise the heart tissue?

Right and left main coronary arteries which arise from the aorta.


Which characteristic of the left coronary artery helps prevent occlusion?

Left anterior descending coronary artery shows bridging - compression of a segment of the artery during systole, resulting in narrowing that reverses during diastole.


What is an end artery?

- Terminal artery supplying all or most of the blood to a body part without significant collateral circulation.
- Undergo progressive branching without the development of channels connective with other arteries - if occluded, there is insufficient blood supply to dependent tissue (hypoxia, pain and cell death).


Give examples of functional and absolute end arteries.

- Functional: coronary arteries, splenic artery, cerebral arteries and renal arteries.
- Absolute (anatomically true): central artery to retina.


What is the response to occlusion in collateral circulation?

Arterial branching develops over time to bypass the occlusion in response to stenosis.


Name the valves located in the heart.

- Tricuspid valve (between right atrium and ventricle)
- Pulmonary valve (between right ventricle and pulmonary artery)
- Mitral valve (between left atrium and ventricle)
- Aortic valve (between left ventricle and aorta)


How is contraction generated in heart cells?

- Natural pacemaker: sinoatrial (SA) node spontaneously generates action potentials.
- AP at SA node causes contraction of right and left atria (travels via Backmann's Bundle)
- AP travels from SA node to atrioventricular (AV) node.
- AP travels down left and right bundle branches and in Purkinje fibres to cause ventricular contraction.


What is the atrioventricular delay?

- Pause in AP conductivity between atria and ventricles.
- Prevents simultaneous contraction to allow ventricular filling.


What is ventricular fibrillation?

- Erratic heart rhythm with no communication between AV node and ventricles. Heart shimmers, no output or contraction.


Describe the general structure of arteries.

1- Tunica intima
- Endothelium
- Subendothelial layer
- Internal elastic lamina
2- Tunica media
- External elastic lamina
3- Tunica adventitia


Describe the general structure of veins.

1- Tunica intima
- Endothelium
- Subendothelial layer
2- Tunica media
3- Tunica adventitia


Which blood vessel gives rise to the major arteries?

The aortic arch. Gives rise to:
- right and left coronary arteries (supplying heart)
- subclavian arteries, common carotid arteries and brachiocephalic trunk (supplying body)


Describe the blood flow/pressure in elastic arteries (aorta).

- Systole: left ventricle contraction causes blood pressure in aorta to rise to approx. 120 mmHg (systolic pressure) - walls of elastic aorta and other elastic arteries stretch.

- Diastole: aortic semilunar valve closes causing aortic pressure to drop to 70-80 mmHg (diastolic pressure) - walls of aorta recoil, maintaining pressure of the blood and moving it towards the small vessels.


Why are elastic arteries called capacitator vessels?

- Act as pressure reservoirs: act as auxiliary pumps during diastole, giving back the elastic energy stored during systole.


How does the structure of elastic arteries support their function?

Tunica media is composed of elastin fibres, collagen and matrix produced by smooth muscle cells as need to be elastic (stretch and recoil).


What is an aneurysm and where is the most common site for this to occur?

- Dilatation of a blood vessel.
- The infrarenal abdominal aorta due to the reduced presence of elastin fibres.