Involvement of adrenoceptors in the ovarian vascular pedicle in the regulation of counter current transfer of steroid hormones to the arterial blood supplying the oviduct and uterus of pigs

Heat and substances, including gases, steroids and peptide hormones, can pass from venous blood, interstitial fluid and lymph to the arterial blood; the process is called local counter-current transfer. It has been found in various reproductive organs in many animal species and in man: from the testis to the testis and epididymis; from the ovary to the ovary, tube and tubal corner of the uterus; from the tube and uterus to the ovary; from vagina to uterus; and even between brain blood vessels. Local transfer within the ovary has also been found. Local cooling that creates temperature gradients between organs or within an organ is one aspect of the transfer. Physiologically, the transfer also facilitates local feedback regulation of organ function in a process situated between general distribution of hormones through the systemic circulation and paracrine regulation. Counter-current transfer of drugs after local application opens up new possibilities for treatment.

Download Full-text

Model of counter-current transfer from vagina to urethra in postmenopausal women

Human Reproduction ◽

10.1093/humrep/16.12.2496 ◽

2001 ◽

Vol 16 (12) ◽

pp. 2496-2500 ◽

Cited By ~ 10

Author(s):

E. Cicinelli ◽

N. Einer-Jensen ◽

P. Galantino ◽

V. Pinto ◽

B. Barba ◽

...

Keyword(s):

Postmenopausal Women ◽

Current Transfer ◽

Counter Current

Download Full-text

Resting oxygenation of rat and rabbit intestine: arteriolar and capillary contributions

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.269.4.h1342 ◽

1995 ◽

Vol 269 (4) ◽

pp. H1342-H1348 ◽

Cited By ~ 8

Author(s):

H. G. Bohlen ◽

J. M. Lash

Keyword(s):

Small Intestine ◽

Tissue Oxygenation ◽

Second Order ◽

Oxygen Exchange ◽

Total Reduction ◽

Arterial Blood ◽

Rabbit Intestine ◽

Counter Current ◽

Vascular Region

Counter-current exchange of oxygen may occur between inflow and outflow microvessels of the small intestine and greatly influence the dominant sites of tissue oxygenation. To determine the location and magnitude of potential exchange, percent saturation of hemoglobin with oxygen (%SHb) was measured in microvessels throughout the intestine of rats and rabbits. Oxygen losses from systemic arterial blood through large and intermediate arterioles (second order, 2A) was 5-7%SHb in both species, and there was no evidence of an increase in percent saturation along intermediate and large venules. A larger loss of oxygen from arterioles and an increase in venous saturation would be evident if significant arteriolar to venular counter-current exchange of oxygen occurred in the submucosa. From 2A to the villus tip, arteriolar saturation decreased approximately 10%SHb in rabbits and approximately 15%SHb in rats; the villus tip percent saturation was 72.9 +/- 3.9%SHb in rabbits and 69.9 +/- 2.9%SHb in rats. An additional decrease of 5%SHb in rabbits and 15%SHb in rats occurred across the villus capillaries and smallest venules. Although the total reduction in percent saturation across the villi was different between the two species, 70-90% of the total arteriovenous oxygen losses occurred in the capillaries and small arterioles of the villi. We found no evidence of counter-current exchange of oxygen in villi or any other vascular region. Rather, as appears to occur in most organs, small arterioles in conjunction with capillaries dominate resting oxygen exchange to tissue.

Download Full-text

Topsy-turvy: turning the counter-current heat exchange of leatherback turtles upside down

Biology Letters ◽

10.1098/rsbl.2015.0592 ◽

2015 ◽

Vol 11 (10) ◽

pp. 20150592 ◽

Cited By ~ 6

Author(s):

John Davenport ◽

T. Todd Jones ◽

Thierry M. Work ◽

George H. Balazs

Keyword(s):

Heat Exchangers ◽

Venous Blood ◽

Vascular Supply ◽

The Body ◽

Leatherback Turtles ◽

The Core ◽

Arterial Blood ◽

Hip Muscles ◽

Counter Current ◽

Current Heat

Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core temperatures in cold seawater and arteriovenous plexuses at the roots of all four limbs. We demonstrate that plexuses of the hindlimbs are situated wholly within the hip musculature, and that, at the distal ends of the plexuses, most blood vessels supply or drain the hip muscles, with little distal vascular supply to, or drainage from the limb blades. Venous blood entering a plexus will therefore be drained from active locomotory muscles that are overlaid by thick blubber when the adults are foraging in cold temperate waters. Plexuses maintain high limb muscle temperature and avoid excessive loss of heat to the core, the reverse of the accepted paradigm. Plexuses protect the core from overheating generated by muscular thermogenesis during nesting.

Download Full-text

Functional and therapeutic aspects of counter current transfer in the female adnexa

Medical Hypotheses ◽

10.1016/0306-9877(90)90190-p ◽

1990 ◽

Vol 33 (2) ◽

pp. 125-127 ◽

Cited By ~ 10

Author(s):

N. Einer-Jensen

Keyword(s):

Current Transfer ◽

Counter Current

Download Full-text

Parametric Studies on the Three-Layer Microcirculatory Model for Surface Tissue Energy Exchange

Journal of Biomechanical Engineering ◽

10.1115/1.3138585 ◽

1986 ◽

Vol 108 (1) ◽

pp. 89-96 ◽

Cited By ~ 15

Author(s):

Z. Dagan ◽

S. Weinbaum ◽

L. M. Jiji

Keyword(s):

Venous Blood ◽

Thermal Characteristics ◽

Tissue Temperature ◽

Capillary Perfusion ◽

Metabolic Heat ◽

Blood Temperature ◽

Arterial Blood ◽

Parametric Studies ◽

Counter Current ◽

Cutaneous Blood

The new three-layer microvascular mathematical model for surface tissue heat transfer developed in [1, 2], which is based on detailed vascular casts and tissue temperature measurements in the rabbit thigh, is used to investigate the thermal characteristics of surface tissue under a wide variety of physiological conditions. Studies are carried out to examine the effects of vascular configuration, arterial blood supply rate, distribution of capillary perfusion, cutaneous blood circulation and metabolic heat production on the average tissue temperature profile, the local arterial-venous blood temperature difference in the thermally significant counter-current vessels, and surface heat flux.

Download Full-text