Mechanisms that control blood flow to body tissues

2021-05-27 01:54 PM

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