Quantitative Analysis of Glabrous Skin Blood Flow and its Role in Human Thermoregulation

2012 ◽  
Author(s):  
Daniel W. Hensley ◽  
Andrew E. Mark ◽  
Eugene H. Wissler ◽  
Kenneth R. Diller
Keyword(s):  
Blood Flow ◽  
The Body ◽  
Glabrous Skin ◽  
Vascular Networks ◽  
Blood Flows ◽  
High Magnitude ◽  
Hairless Skin ◽  
Thermoregulatory System ◽  
And Control ◽  
Human Thermoregulation

Glabrous (hairless) skin found on the hands, feet, face, and ears is a unique component of the thermoregulatory system. Its anatomy and control physiology differ markedly from those of the rest of the skin. Glabrous regions contain vascular networks capable of supporting large blood flows due to the presence of highly tortuous and densely packed arteriovenous anastomoses (AVAs) and associated venous collecting networks [1]. When dilated, these vessels bring large volumes of blood close to the body surface where they function as highly efficient heat exchangers. Furthermore, the manner in which this blood flow is controlled is very unique, exhibiting, for example, rapid and high-magnitude responses, as well as a greater sensitivity to central core signals [1]. In this light, glabrous skin is an important but often overlooked tool the body uses to rapidly and finely adjust energy balance to maintain thermal equilibrium.

COMPARISON OF ANTIHYPERTENSIVE EFFECT OF MOXONIDINE VERSUS CLONIDINE IN RENAL FAILURE PATIENTS.

2018 ◽  
Vol 6 (9) ◽  
Author(s):  
DR.MATHEW GEORGE ◽  
DR.LINCY JOSEPH ◽  
MRS.DEEPTHI MATHEW ◽  
ALISHA MARIA SHAJI ◽  
BIJI JOSEPH ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Failure ◽  
Blood Flow ◽  
Blood Vessel ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Antihypertensive Effect ◽  
The Body ◽  
Ability To Work ◽  
Blood Flows

Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body. Factors that can increase this force include higher blood volume due to extra fluid in the blood and blood vessels that are narrow, stiff, or clogged(1). High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.

NO supports right ventricular flow dominance and whole body O2 utilization in midgestation fetal lambs

2001 ◽  
Vol 280 (4) ◽  
pp. R1016-R1022 ◽  
Author(s):  
Joseph J. Smolich
Keyword(s):  
Blood Flow ◽  
Flow Distribution ◽  
The Body ◽  
Whole Body ◽  
Blood Flow Distribution ◽  
Blood Flows ◽  
Blood Flow Ratio ◽  
Placental Blood ◽  
Flow Changes ◽  
Placental Blood Flow

It is unknown if nitric oxide (NO) modulates the relative levels of left (LV) and right (RV) ventricular output, fetal O2 consumption, or blood flow distribution between the body and placenta at midgestation. To address these questions, six fetal lambs were instrumented at 89–96 days gestation (term 147 days), and blood flows were measured with radioactive microspheres 3–4 days later at baseline and after inhibition of NO synthesis with 10 mg/kg (l-NNA10) and 25 mg/kg (l-NNA25) N ω-nitro-l-arginine. LV output fell by 74 ± 15 ml · min−1 · kg−1 atl-NNA10 ( P < 0.005), whereas RV output decreased by 90 ± 18 ml · min−1 · kg−1 atl-NNA10 ( P < 0.02) and by a further 80 ± 22 ml · min−1 · kg−1 atl-NNA25 ( P < 0.05). As a result, RV output exceeded LV output at baseline ( P = 0.03) and l-NNA10 ( P < 0.02) but not at l-NNA25. Fetal body blood flow fell by 95 ± 25 ml · min−1 · kg−1 atl-NNA10 ( P < 0.01), but because placental blood flow decreased by 70 ± 22 ml · min−1 · kg−1 atl-NNA10 ( P < 0.01) and a further 71 ± 21 ml · min−1 · kg−1 atl-NNA25 ( P < 0.01), the fetal body-to-placental blood flow ratio was near unity at baseline andl-NNA10 but rose to 1.5 ± 0.3 atl-NNA25 ( P < 0.05). In association with these flow changes, fetal O2 consumption declined by 1.4 ± 0.3 ml · min−1 · kg−1 atl-NNA10 ( P < 0.05) and by a further 1.5 ± 0.6 ml · min−1 · kg−1 atl-NNA25 ( P < 0.02). These findings suggest that, in midgestation fetal lambs, NO supports an RV flow dominance, whole body O2 utilization, and the maintenance of a near-equal fetoplacental blood flow distribution.

scholarly journals Effect of Electrical Stimulation on Blood Flow in Calf Muscles in Different Body Positions

2018 ◽  
Vol 1 (96) ◽  
Author(s):  
Julius Dovydaitis ◽  
Albinas Grūnovas
Keyword(s):  
Blood Flow ◽  
Body Position ◽  
Venous Blood ◽  
The Body ◽  
Arterial Blood Flow ◽  
Reserve Capacity ◽  
Horizontal Position ◽  
Blood Flows ◽  
Arterial Blood ◽  
Electrical Muscle

Background.  In  most  studies  on  cardiovascular  system,  testing  of  subjects  was  performed  in  a  horizontal position. With the change of the body position, certain functional changes occur in the cardiovascular system. The aim of this study was to analyze the effect of electrical muscle stimulation (EMS) on arterial and venous blood flows.Methods. Eighteen athletes aged 19–23 performed two sessions of tests in horizontal and sitting positions. Changes in arterial and venous blood flows were recorded before and after EMS. In each session two occlusions were performed. In the horizontal position, the initial occlusion pressure of 20 mmHg was applied and as the balance in arterial and venous blood flow rates was reached, the additional pressure of 20 mmHg (40  mmHg in total). In the sitting position, the occlusion pressure of 40 and 20 mmHg was applied respectively (60 mmHg in total). In both sessions EMS was performed using the electrical stimulator Mioritm 021.Results. In both horizontal and vertical positions, the effect of EMS on arterial blood flow, venous reserve capacity and venous elasticity was insignificant. Arterial and venous blood flows was affected significantly by the change of the body position. In the sitting position, arterial blood flow was significantly (p < .05) lower compared to the horizontal position. Similar results were recorded in venous reserve capacity.Conclusion.  The  study  suggests  that  blood  flow  in  the  calf  muscles  is  affected  by  the  body  position  and hydrostatic pressure; arterial blood flow increases in the horizontal body position.Keywords:  electrical muscle stimulation (EMS), arterial blood flow, venous reserve capacity, venous elasticity

NO modulates fetoplacental blood flow distribution and whole body oxygen extraction in fetal sheep

1998 ◽  
Vol 274 (5) ◽  
pp. R1331-R1337 ◽  
Author(s):  
Joseph J. Smolich
Keyword(s):  
Blood Flow ◽  
Flow Distribution ◽  
The Body ◽  
Whole Body ◽  
Blood Flow Distribution ◽  
Relative Level ◽  
Fetal Sheep ◽  
Placental Perfusion ◽  
Blood Flows ◽  
Placental Blood

It is unknown if nitric oxide (NO) influences the relative level of the left (LV) and right ventricular (RV) outputs, the blood flow distribution between the body and placenta, or whole body O2extraction and O2 consumption in the fetus. To address these questions eight fetal lambs were chronically instrumented at 128–134 days gestation (term 147 days), and blood flows were measured with radioactive microspheres 3–4 days later at baseline and after inhibition of NO synthesis with N ω-nitro-l-arginine (l-NNA, 10 and 25 mg/kg iv).l-NNA progressively reduced the combined ventricular output ( P < 0.005) but did not alter the relative levels of the LV and RV outputs. Fetal body blood flow fell by 31% after 10 mg/kgl-NNA ( P < 0.005), but a reduction in placental blood flow ( P < 0.005) was smaller (20%) and not observed until 25 mg/kgl-NNA. Whole body O2 extraction increased by 71% after 10 mg/kg l-NNA ( P < 0.005) and did change further at 25 mg/kg l-NNA, whereas whole body O2 consumption rose by 15% at 10 mg/kg l-NNA ( P < 0.05) and returned to baseline at 25 mg/kg l-NNA. These results suggest that, as well as reducing the combined ventricular output, inhibition of fetal NO synthesis redistributes systemic blood flow toward the placenta and increases fetal body O2 extraction. The latter initially increases whole body O2consumption and then maintains it at near baseline levels after a fall in placental perfusion.

Systemic adenosine deaminase administration does not reduce active hyperemia in running rats

1988 ◽  
Vol 64 (1) ◽  
pp. 108-114 ◽  
Author(s):  
R. E. Klabunde ◽  
M. H. Laughlin ◽  
R. B. Armstrong
Keyword(s):  
Blood Flow ◽  
Adenosine Deaminase ◽  
Skeletal Muscles ◽  
Muscle Blood Flow ◽  
Experimental Period ◽  
Blood Flows ◽  
Slow Twitch ◽  
Fast Twitch ◽  
And Control ◽  
Total Muscle

The importance of adenosine in controlling the magnitude and distribution of blood flow among and within skeletal muscles in rats during slow locomotor exercise was tested by systemic infusion of adenosine deaminase (ADA). Blood flows were measured using labeled microspheres before exercise and at 0.5, 15, and 30 min of fast treadmill walking at 15 m/min. An initial infusion of ADA (1,000 U/kg) was given 30 min before the first blood flow measurement and a second injection (1,000 U/kg) was given 5 min into exercise. These infusions maintained ADA activity above 5 U/ml blood throughout the experimental period. This plasma concentration of ADA was shown to be sufficient to result in a 64% decrease in muscle adenosine levels during ischemic contraction. Blood flows were measured in all of the muscles of the hindlimb (28 samples) and in various nonmuscular tissues in ADA-treated and control rats. Preexercise blood flows were primarily directed to slow-twitch muscles and exercise blood flows were highest in muscles with fast-twitch oxidative fibers. ADA treatment did not reduce total muscle blood flow or exercise blood flows in any of the muscles at any time. These findings do not support the hypothesis that adenosine plays an essential role in controlling muscle blood flow in skeletal muscles during normal locomotor activity.

Role of prostaglandins and nitric oxide in gastrointestinal hyperemia of diabetic rats

1996 ◽  
Vol 270 (4) ◽  
pp. G684-G690 ◽  
Author(s):  
E. Goldin ◽  
M. Casadevall ◽  
M. Mourelle ◽  
I. Cirera ◽  
J. I. Elizalde ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Gastric Mucosa ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Left Gastric Artery ◽  
Diabetic Rats ◽  
Gastric Artery ◽  
Blood Flows ◽  
And Control

The aim of the study was to characterize the gastric and mesenteric vascular changes induced by diabetes and the implication of endothelial [nitric oxide (NO) and prostaglandins] and humoral (glucagon) factors in such changes. Diabetes was induced in rats by a single streptozotocin injection. Four weeks later, gastric mucosa, left gastric artery, and superior mesenteric artery blood flows were measured using hydrogen gas clearance and perivascular ultrasonic flowmeter techniques, respectively, in anesthetized and fasted diabetic and control rats. Blood pressure, hematocrit, blood volume, and blood viscosity were also measured. Left gastric (41 +/- 6 vs. 25 +/- 4 ml.min-1.100 g-1) and superior mesenteric artery blood flows (83 +/- 8 vs. 65 +/- 4 ml.min-1.100 g-1) were significantly higher in diabetic than in control rats. The increased blood flow in the left gastric artery was distributed to a hypertrophic mucosa in diabetic rats; therefore, the blood flow per 100 g tissue in the gastric mucosa was not significantly different in diabetic compared with control rats. Pretreatment with indomethacin reduced both increase gastric and mesenteric flows of the diabetic rats to the same levels as in control rats. NG-nitro-L-arginine methyl ester decreased gastric blood flow in a dose-dependent manner and to a similar extent in diabetic and control rats. In contrast, an increased sensitivity to the higher doses of the NO inhibitor was observed in the mesenteric vascular bed of diabetic rats. Glucagon reduction achieved by somatostatin infusion did not influence either gastric or mesenteric blood flow in diabetic rats. In summary, the present study revealed an increase in gastric and mesenteric arterial blood flows in streptozotocin-induced diabetic rats. The gastrointestinal hyperemia seems to be due, at least in part, to the increased demand of a hypertrophic mucosa and is mediated primarily by endogenous prostaglandins. Increased vascular sensitivity to NO may also contribute to the mesenteric vasodilation.

Effects of emphysema on diaphragm blood flow during exercise

1998 ◽  
Vol 84 (3) ◽  
pp. 971-979 ◽  
Author(s):  
William L. Sexton ◽  
David C. Poole
Keyword(s):  
Blood Flow ◽  
Treadmill Exercise ◽  
Work Of Breathing ◽  
Regional Distribution ◽  
Blood Flows ◽  
Syrian Golden Hamsters ◽  
Unit Body Weight ◽  
Crural Diaphragm ◽  
Exercise Induced ◽  
And Control

Chronic hyperinflation of the lung in emphysema displaces the diaphragm caudally, thereby placing it in a mechanically disadvantageous position and contributing to the increased work of breathing. We tested the hypothesis that total and regional diaphragm blood flows are increased in emphysema, presumably reflecting an increased diaphragm energetic demand. Male Syrian Golden hamsters were randomly divided into emphysema (E; intratracheal elastase 25 units/100 g body wt) and control (C; saline) groups, and experiments were performed 16–20 wk later. The regional distribution of blood flow within the diaphragm was determined by using radiolabeled microspheres in hamsters at rest and during treadmill exercise (walking at 20 feet/min, 20% grade). Consistent with pronounced emphysema, lung volume per unit body weight was greater in E hamsters (C, 59.3 ± 1.8; E, 84.5 ± 5.0 ml/kg; P < 0.001) and arterial[Formula: see text] was lower both at rest (C, 74 ± 3; E, 59 ± 2 Torr; P < 0.001) and during exercise (C, 93 ± 3; E, 69 ± 4 Torr; P < 0.001). At rest, total diaphragm blood flow was not different between C and E hamsters (C, 47 ± 4; E, 38 ± 4 ml ⋅ min−1 ⋅ 100 g−1; P = 0.18). In both C and E hamsters, blood flow at rest was lower in the ventral costal region of the diaphragm than in the dorsal and medial costal regions and the crural diaphragm. During exercise in both C and E hamsters, blood flows increased more in the dorsal and medial costal regions and in the crural diaphragm than in the ventral costal region. Total diaphragm blood flow was greater in E hamsters during exercise (C, 58 ± 7; E, 90 ± 14 ml ⋅ min−1 ⋅ 100 g−1; P = 0.03), as a consequence of significantly higher blood flows in the medial and ventral costal regions and crural diaphragm. In addition, exercise-induced increases in intercostal ( P < 0.005) and abdominal ( P < 0.05) muscle blood flows were greater in E hamsters. The finding that diaphragm blood flow was greater in E hamsters during exercise supports the contention that emphysema increases the energetic requirements of the diaphragm.

Cerebral blood flow in intoxicated newborn piglets

1987 ◽  
Vol 65 (1) ◽  
pp. 92-95 ◽  
Author(s):  
Cara J. MacIntyre ◽  
Bill Y. Ong ◽  
Daniel S. Sitar
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Basal Ganglia ◽  
Brain Regions ◽  
Ethanol Exposure ◽  
Blood Flows ◽  
Arterial Blood ◽  
Regional Blood Flows ◽  
Blood Pressures ◽  
And Control

Ethanol exposure in the neonatal period causes impaired brain growth and altered adult behaviour in rats. One possible mechanism may be altered cerebral perfusion caused by ethanol intoxication. We assessed the effects of ethanol on cerebral blood flow and its autoregulation in 2-day-old piglets. Piglets received ethanol (1.4 g/kg) or an equivalent volume of dextrose 5% in water over 30 min. One hour later, cerebral blood flow was measured using the microsphere technique at resting, elevated, and decreased mean arterial blood pressure. Ethanol-treated piglets had total cerebral blood flows of 88 ± 14, 82 ± 10, and 82 ± 12 mL∙100 g−1∙min−1 (mean ± SE) at mean arterial blood pressures of 12.4 ± 1.1, 15.7 ± 1.5, and 8.2 ± 0.9 kPa. Corresponding values in control piglets were 82 ± 14, 78 ± 4, and 82 ± 7 mL∙100 g−1∙min−1 at mean arterial blood pressures of 10.5 ± 1.5, 14.0 ± 1.2, and 7.7 ± 1.1 kPa. At resting arterial blood pressures, regional blood flows to basal ganglia, cortex, brainstem, and cerebellum in ethanol-treated piglets were 123 ± 21, 90 ± 16, 94 ± 17, and 77 ± 12 mL∙100 g−1∙min−1, respectively. Corresponding regional blood flows for the control piglets were 118 ± 16, 85 ± 15, 76 ± 16, and 76 ± 16 mL∙100 g−1∙min−1. Blood flow to basal ganglia was greater than to other brain regions in both ethanol-treated and control piglets (P < 0.01). Total and regional blood flows remained unchanged with altered mean arterial blood pressures, indicating normal autoregulation of cerebral blood flow in both ethanol-treated and control piglets.

scholarly journals Mechanoreceptor synapses in the brainstem shape the central representation of touch

2021 ◽  
Author(s):  
Brendan P. Lehnert ◽  
Celine Santiago ◽  
Erica L. Huey ◽  
Alan J. Emanuel ◽  
Sophia Renauld ◽  
...  
Keyword(s):  
The Body ◽  
Glabrous Skin ◽  
Disproportionate Representation ◽  
Synaptic Connections ◽  
Large Numbers ◽  
Central Representation ◽  
Hairless Skin ◽  
Central Synapses ◽  
Hands And Feet ◽  
The Brain

AbstractMammals use glabrous (hairless) skin of their hands and feet to navigate and manipulate their environment. Cortical maps of the body surface across species contain disproportionately large numbers of neurons dedicated to glabrous skin sensation, potentially reflecting a higher density of mechanoreceptors that innervate these skin regions. Here, we find that disproportionate representation of glabrous skin emerges over postnatal development at the first synapse between peripheral mechanoreceptors and their central targets in the brainstem. Mechanoreceptor synapses undergo developmental refinement that depends on proximity of their terminals to glabrous skin, such that those innervating glabrous skin make synaptic connections that expand their central representation. In mice that do not sense gentle touch, mechanoreceptors innervating glabrous skin still make more powerful synaptic connections in the brainstem. We propose that the skin region a mechanoreceptor innervates controls refinement of its central synapses over development to shape the representation of touch in the brain.

What is the Blood Flow to Resting Human Muscle?

1993 ◽  
Vol 84 (5) ◽  
pp. 559-563 ◽  
Author(s):  
M. Elia ◽  
A. Kurpad
Keyword(s):  
Blood Flow ◽  
Adipose Tissue ◽  
Muscle Blood Flow ◽  
The Body ◽  
Blood Flows ◽  
133Xe Clearance ◽  
Forearm Skin ◽  
The Mean ◽  
Subcutaneous Adipose ◽  
Clearance Technique

1. An investigation was carried out in five healthy lean adults to assess whether forearm and calf plethysmography largely reflect muscle blood flow as measured by 133Xe and whether there is substantial variability in the blood flow to muscles located at different sites in the body. 2. Blood flow to forearm and calf flexors and extensors, biceps, triceps and quadriceps was assessed using the 133Xe clearance technique. Blood flow to forearm skin and subcutaneous adipose tissue was also measured using the 133Xe clearance technique, whereas blood flow to the forearm and calf was measured using strain gauge plethysmography. 3. The mean blood flow to different muscles ranged from 1.4 ± 0.6 (gastrocnemius) to 1.8 ± 0.7 (forearm extensor) ml min−1 100 g−1 muscle (1.4 ± 0.6 and 1.9 ± 0.8 ml min−1 100 ml−1 muscle, respectively) but there were no significant differences between them. Forearm and calf blood flows (2.7 ± 0.3 and 3.0 ± 0.7 ml min−1 100 ml−1 limb tissue, respectively) were about 50% to more than 100% greater (P <0.025) than blood flow to the muscles within them (1.7 ± 0.5 and 1.4 ± 0.5ml min−1 100g−1 muscle, respectively, or 1.8 ± 0.6 and 1.5 ± 0.5 ml min−1 100 ml−1 muscle, respectively). In contrast, the blood flows to 100 g of forearm skin (9.1 ± 2.6 ml min−1 100 g−1) and adipose tissue (3.8 ± 1.1 ml min−1 100 g−1) were higher than the blood flow to 100 g of forearm (P <0.01 and not significant, respectively). 4. Although several possibilities can explain the discrepancy between muscle blood flow measured by 133Xe and blood flow to the distal limbs measured by plethysmography, the results suggest that non-muscular blood flow, especially that to skin, is substantially greater than muscular blood flow. Indeed, the overall blood flow to the forearm could be accounted for by summation of blood flows to individual constituent tissues, which were assumed to be present in proportions typical of lean subjects. The results have important implications in the use of arteriovenous catheterization studies for assessing flux of oxygen, carbon dioxide and metabolites across muscle.

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