Cardiovascular System and Oedema Flashcards
What is the pulmonary circulation?
Where blood circulates from the heart to the lungs
What is systemic circulation?
Where blood travels from the heart to the rest of the body.
What is an end artery?
An artery that is the only supply of oxygenated blood to a tissue
What happens to correct blocked end arteries?
Collateral circulation is established
What happens in systole?
The left ventricle contracts and so blood pressure increases in the aorta
What happens to the aorta during dystole?
Recoils maintaining the pressure of the blood
What are the 3 layers of arteries?
Tunica intima (endothelium), Tunis media (smooth muscle and elastic fibres), tunica adventitia (collagen, elastic fibres and CT)
What is an aneurysm?
Dilation of blood vessels
What are pericytes?
Cells that line capillaries and venuoles which are capable of dividing into muscle cells or fibroblasts
What are capacitance vessels?
Vessels that are able to increase the volume of blood they hold without increasing pressure
What actions allow blood to be returned to the heart through veins?
Pressure changes in the thorax, contractions of skeletal muscle, valves
What does the frank sterling curve state?
The more that goes into the heart, the more that comes out
How do diuretics decrease blood pressure
As you lose more water in your urine, therefore less is reabsorbed to go into the blood so you have a smaller blood volume giving a lower pressure
What is paroxysmal nocturnal dyspnoea?
Difficulty in breathing at night
What is orthopnea?
Breathlessness
How does left heart failure lead to pulmonary oedema?
Blood backs up in the veins as you can’t pump it back properly. Therefore there’s an increase in pressure in the veins so more fluid is forced out and not reabsorbed and this fluid can accumulate in the alveoli
What is oedema?
Accumulation of excess watery fluid in cells and tissues
What is Lymphoedema?
Excess of lymph fluid causing swelling
What causes lymphoedema
Obstruction in lymph nodes or Lymphatic vessels
Why does lympoedema not pit?
As lymph fluid contains lots of proteins making it very thick
What are 3 causes of oedema?
- Increased hydrostatic pressure
- Reduced oncotic pressure in blood vessels
- Increased permeability of blood vessels
How does liver damage cause oedema?
There’s less albumin produced so oncotic pressure falls meaning that there’s an increase in hydrostatic pressure
Why does oedema appear at the ankles
Gravity
What is the pressure in the arterioles?
35mmHg
What is the pressure in the venuoles?
15mmHg
