276
A. Colantuoni and D. Lapi
4
3
2
1
Long arteriolar terminal tree
Short arteriolar terminal tree
Point of acƟvity
Point of acƟvity
3
3
2
1
5
Arcade arteriole
Fig. 17.1 Scheme of a microvascular network in hamster skeletal muscle (Cutaneous Maximus).
The arcade arteriole is an order 5 arteriole with two branchings: the long terminal arteriolar tree and
the short terminal arteriolar tree. At branching, the long and short terminal trees present an active
point of contraction and dilation. In the long terminal arteriolar tree, there is at least another point
of activity at the first branching of order 4 arteriole
arterioles were differentiated in short and long terminal arteriolar trees, where the
long ones were characterized by larger vessels undergoing constriction and dilation
from the branching point (Fig. 17.1). This activity was conducted to all daughter
vessels with different amplitude (50–70% in order 4, 90–100% in order 2 and 1) and
caused intermittent blood flow in capillaries, according to the constriction or dilation
of the smallest arterioles. The short terminal trees were characterized by order 3
arterioles (diameter: 19.4 ± 3.0 μm) spreading from arcading arterioles (diameter:
39.6 ± 5.7 μm) and able to completely constrict, inducing opening and closing of
downstream arterioles. Therefore, there was consequent intermittent blood flow in
all capillaries originating from the smallest order 1 arterioles, present in the terminal
tree. These rhythmic diameter changes were observed in awake animals without
anaesthesia, with complex superposition of waves spreading from larger vessels up
to the terminal arterioles.
The microvascular scenario could be summarized as the interplay of larger arteriolar anastomoses and the terminal branching vessels. The arcade arterioles full of
blood facilitate the blood supply to the skeletal muscle cells; these vessels are characterized by slow oscillations in diameter and repeated inversion in the direction of
blood flow during a minute time interval. These arterioles gave origin to terminal arteriolar trees, that presented a point of activity at their beginning, where a mechanism
A. Colantuoni and D. Lapi
4
3
2
1
Long arteriolar terminal tree
Short arteriolar terminal tree
Point of acƟvity
Point of acƟvity
3
3
2
1
5
Arcade arteriole
Fig. 17.1 Scheme of a microvascular network in hamster skeletal muscle (Cutaneous Maximus).
The arcade arteriole is an order 5 arteriole with two branchings: the long terminal arteriolar tree and
the short terminal arteriolar tree. At branching, the long and short terminal trees present an active
point of contraction and dilation. In the long terminal arteriolar tree, there is at least another point
of activity at the first branching of order 4 arteriole
arterioles were differentiated in short and long terminal arteriolar trees, where the
long ones were characterized by larger vessels undergoing constriction and dilation
from the branching point (Fig. 17.1). This activity was conducted to all daughter
vessels with different amplitude (50–70% in order 4, 90–100% in order 2 and 1) and
caused intermittent blood flow in capillaries, according to the constriction or dilation
of the smallest arterioles. The short terminal trees were characterized by order 3
arterioles (diameter: 19.4 ± 3.0 μm) spreading from arcading arterioles (diameter:
39.6 ± 5.7 μm) and able to completely constrict, inducing opening and closing of
downstream arterioles. Therefore, there was consequent intermittent blood flow in
all capillaries originating from the smallest order 1 arterioles, present in the terminal
tree. These rhythmic diameter changes were observed in awake animals without
anaesthesia, with complex superposition of waves spreading from larger vessels up
to the terminal arterioles.
The microvascular scenario could be summarized as the interplay of larger arteriolar anastomoses and the terminal branching vessels. The arcade arterioles full of
blood facilitate the blood supply to the skeletal muscle cells; these vessels are characterized by slow oscillations in diameter and repeated inversion in the direction of
blood flow during a minute time interval. These arterioles gave origin to terminal arteriolar trees, that presented a point of activity at their beginning, where a mechanism