- Home
- Medical books
- Medical Physiology
- Mechanisms that control blood flow to body tissues
Mechanisms that control blood flow to body tissues
Immediate control is achieved by constricting or relaxing the arterioles, capillaries, and precapillary sphincters, within seconds to minutes. Long-term control changes gradually, over a period of days, weeks or even months.
Local blood flow control can be divided into 2 phases: (1) immediate control and (2) long-term control.
Immediate control is achieved by rapidly changing contraction or dilation of the arterioles, capillaries, and precapillary sphincters, occurring within seconds to minutes to deliver the required amount of blood to the local tissue.
Long-term control means gradual, controlled changes in blood flow over a period of days, weeks or even months. Overall, these long-term changes produce better blood flow control, in balance with the needs of the tissue. These changes occur as a result of an increase or decrease in the size and amount of blood supply to the tissue.
Figure. Effect of increased metabolic rate on blood flow to tissues
Board. Blood to organs and tissues is in the basal state
|
|
Percentage of cardiac output |
ml/min |
ml/min/100g tissue |
|
No |
14 |
700 |
50 |
|
Tim |
4 |
200 |
70 |
|
Pulmonary peduncle |
2 |
100 |
25 |
|
Kidney |
22 |
1100 |
360 |
|
Gan |
27 |
1350 |
95 |
|
Door system |
(21) |
(1050) |
|
|
Artery |
(6) |
(300) |
|
|
Muscle (inactive state) |
15 |
750 |
4 |
|
Bone |
5 |
250 |
3 |
|
Skin (cold weather) |
6 |
300 |
3 |
|
Thyroid |
1 |
50 |
160 |
|
Adrenals |
0.5 |
25 |
300 |
|
Other tissue |
3.5 |
175 |
1.3 |
|
total |
100.0 |
5000 |
|