Properties of circulation in the coronaries, the skin, the brain, splanchnic circulation and the fetal circulation

Question 1

Organs with specialized circulations:

Answer 1

1. Coronary circulation (heart)
2. Circulation of the brain
3. Circulation of the skin
4. Splanchnic (portal) circulation
5. Fetal circulation

Question 2

The right coronary artery:

Answer 2

• Give vessels taht supply the right atrium and the right ventricle.
• The vessels usually continous as the posterir descending coronary artery which supplies the posterior part of the interventricular septum and the posterior left ventricular wall.

Question 3

The left coronary artery:

Answer 3

• The first part is known as the left main.
• it divides into the left anterior descending and the left circumflex arteries.
• the left anterior descending rundt in the anterior interventricular groove and supplies the anterior septum and the anterior left ventricular wall.
• the left circumflex supplies to the left atrium and the left ventricle.
• The conduction system is supplied by the coronary artery as well.

Question 4

What happens in the beginning of the Systole?

Answer 4

At the beginning of systole the tension in the left chamber is so high that the blood is pressed out from the coronary vessels.
- Reverse flow of blood occurs.

Question 5

What happens in the phase of fast ejection?

Answer 5

The pressure in the aorta is so high, that it can ensure the coronary flow inspite of the very large wall tension of the left chamber.
- During slow ejectiong the wall tension is still high, but the aortic pressure drops. this results in slower, coronary perfusion.

Question 6

What happens during Diastole?

Answer 6

Aortic blood pressure us still high while the ventricles relax.

• Accordinly macimum coronary flow can be mearued.
• more blood enters the coronary vessels during diastole than during systole

Question 7

Circulation of the brain:

Answer 7

• the whole brain has a constant blood flow

- The relative blood flow shows significant differences in brain areas with different metabolism -> PET scan

Question 8

What is Closed cerebral activity?

Answer 8

the arterial blood flow entering the cavity and venous blood flow leaving it have to be equal.

Question 9

Splanchnic circulation:

Answer 9

• Double capillary system (serially attached) -> portal circulation
• Main regulator is the sympathetic tone

Question 10

What is the main regulator is Splanchnic circulation?

Answer 10

Sympathetic tone (alpha-rec)