Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. The walls of all blood vessels except the smallest consist of three layers: the tunica intima, tunica media, and tunica externa.
Elastic, or conducting, arteries contain large amounts of elastin, which enables these vessels to withstand and smooth out pressure fluctuations due to heart action.
Muscular, or distributing, arteries deliver blood to specific body organs, and have the greatest proportion of tunica media of all vessels, making them more active in vasoconstriction. Arterioles are the smallest arteries and regulate blood flow into capillary beds through vasoconstriction and vasodilation. Capillaries are the smallest vessels and allow for exchange of substances between the blood and interstitial fluid.
Fenestrated capillaries are more permeable to fluids and solutes than continuous capillaries.
Sinusoidal capillaries are leaky capillaries that allow large molecules to pass between the blood and surrounding tissues.
Capillary beds are microcirculatory networks consisting of a vascular shunt and true capillaries, which function as the exchange vessels. A cuff of smooth muscle, called a precapillary sphincter, surrounds each capillary at the metarteriole and acts as a valve to regulate blood flow into the capillary. Venules are formed where capillaries converge and allow fluid and white blood cells to move easily between the blood and tissues. Venules join to form veins, which are relatively thin-walled vessels with large lumens containing about 65% of the total blood volume. If blood pressure increases, blood flow increases; if peripheral resistance increases, blood flow decreases. The pumping action of the heart generates blood flow; pressure results when blood flow is opposed by resistance. Systemic blood pressure is highest in the aorta, and declines throughout the pathway until it reaches 0 mm Hg in the right atrium.
Arterial blood pressure reflects how much the arteries close to the heart can be stretched (compliance, or distensibility), and the volume forced into them at a given time. When the left ventricle contracts, blood is forced into the aorta, producing a peak in pressure called systolic pressure (120 mm Hg). Diastolic pressure occurs when blood is prevented from flowing back into the ventricles by the closed semilunar valve, and the aorta recoils (70–80 mm Hg). The mean arterial pressure (MAP) represents the pressure that propels blood to the tissues. Capillary blood pressure is low, ranging from 40–20 mm Hg, which protects the capillaries from rupture, but is still adequate to ensure exchange between blood and tissues. Short-term mechanisms include both (1) neural and (2) hormonal controls, which alter blood pressure by changing peripheral resistance and CO. Most neural controls work through reflex arcs that send information on stretch to effectors (muscle) that respond accordingly. The cortex and hypothalamus can modify arterial pressure by signaling the medullary centers.
Atrial natriuretic peptide acts as a vasodilator and an antagonist to aldosterone, resulting in a drop in blood volume. Antidiuretic hormone promotes vasoconstriction and water conservation by the kidneys, resulting in an increase in blood volume.
Angiotensin II acts as a vasoconstrictor, as well as promoting the release of aldosterone and antidiuretic hormone. Endothelium-derived factors promote vasoconstriction, and are released in response to low blood flow. Nitric oxide is produced in response to high blood flow or other signaling molecules, and promotes systemic and localized vasodilation.
Inflammatory chemicals, such as histamine, prostacyclin, and kinins, are potent vasodilators.
Alcohol inhibits antidiuretic hormone release and the vasomotor center, resulting in vasodilation.
Monitoring circulatory efficiency is accomplished by measuring pulse and blood pressure; these values together with respiratory rate and body temperature are called vital signs. A pulse is generated by the alternating stretch and recoil of elastic arteries during each cardiac cycle.
Systemic blood pressure is measured indirectly using the ascultatory method, which relies on the use of a blood pressure cuff to alternately stop and reopen blood flow into the brachial artery of the arm. Alterations in blood pressure may result in hypotension (low blood pressure) or transient or persistent hypertension (high blood pressure).
Metabolic controls of autoregulation are most strongly stimulated by a shortage of oxygen at the tissues. NO - Nitric oxide, released from endothelial cells locally or from hemoglobin can stimulate relaxation of smooth cells and inhibit production of endothelin synthesis by endothelial cells. Long-term autoregulation develops over weeks or months, and involves an increase in the size of existing blood vessels and an increase in the number of vessels in a specific area, a process called angiogenesis. Muscular autoregulation occurs almost entirely in response to decreased oxygen concentrations. Cerebral blood flow is tightly regulated to meet neuronal needs, since neurons cannot tolerate periods of ischemia, and increased blood carbon dioxide causes marked vasodilation.
In the skin, local autoregulatory events control oxygen and nutrient delivery to the cells, while neural mechanisms control the body temperature regulation function.
Autoregulatory controls of blood flow to the lungs are the opposite of what happens in most tissues: low pulmonary oxygen causes vasoconstriction, while higher oxygen causes vasodilation.


Movement of blood through the coronary circulation of the heart is influenced by aortic pressure and the pumping of the ventricles.
Vasomotion, the slow, intermittent flow of blood through the capillaries, reflects the action of the precapillary sphincters in response to local autoregulatory controls. Capillary exchange of nutrients, gases, and metabolic wastes occurs between the blood and interstitial space through diffusion.
Colloid osmotic pressure (OP), the force opposing hydrostatic pressure, is created by the presence of large, nondiffusible molecules that are prevented from moving through the capillary membrane.
Fluids will leave the capillaries if net HP exceeds net OP, but fluids will enter the capillaries if net OP exceeds net HP. Circulatory shock is any condition in which blood volume is inadequate and cannot circulate normally, resulting in blood flow that cannot meet the needs of a tissue. Hypovolemic shock results from a large-scale loss of blood, and may be characterized by an elevated heart rate and intense vasoconstriction. Vascular shock is characterized by a normal blood volume, but extreme vasodilation, often related to a loss of vasomotor tone, resulting in poor circulation and a rapid drop in blood pressure. Septic shock - bacterial toxins, some increase vascular permeability and lower blood volume and others stimulate vasodilation. Transient vascular shock is due to prolonged exposure to heat, such as while sunbathing, resulting in vasodilation of cutaneous blood vessels.
Cardiogenic shock occurs when the heart is too inefficient to sustain normal blood flow, and is usually related to myocardial damage, such as repeated myocardial infarcts. There is one terminal systemic artery, the aorta, but two terminal systemic veins: the superior and inferior vena cava. Arteries run deep and are well protected, but veins are both deep, running parallel to the arteries, and superficial, running just beneath the skin.
Arterial pathways tend to be clear, but there are often many interconnections in venous pathways, making them difficult to follow.
There are at least two areas where venous drainage does not parallel the arterial supply: the dural sinuses draining the brain, and the hepatic portal system draining from the digestive organs to the liver before entering the main systemic circulation. Four paired arteries supply the head and neck (common carotid arteries and three branches from the subclavian arteries; the vertebral arteries, the thyrocervical trunks, and the costocervical trunks. The internal iliac arteries serve mostly the pelvic region; the external iliacs supply blood to the lower limb and abdominal wall.
Blood drained from the head and neck is collected by three pairs of veins (internal jugular veins, external jugular veins, and the vertebral veins).
Blood draining from the abdominopelvic viscera and abdominal walls is returned to the heart by the inferior vena cava.
The vascular endothelium is formed by mesodermal cells that collect throughout the embryo in blood islands, which give rise to extensions that form rudimentary vascular tubes. By the fourth week of development, the rudimentary heart and vessels are circulating blood. Fetal vascular modifications include shunts to bypass fetal lungs (the foramen ovale and ductus arteriosus), the ductus venosus that bypasses the liver, and the umbilical arteries and veins, which carry blood to and from the placenta. Congenital vascular problems are rare, but the incidence of vascular disease increases with age, leading to varicose veins, tingling in fingers and toes, and muscle cramping. Obesity hypoventilation syndrome is one of the breathing disorders in people who are obese in which poor breathing may leads to higher carbon dioxide and lower oxygen levels in blood. Low levels of oxygen in blood can cause shortness of breathing or feeling tired after little effort. Exact cause behind OHS is not clear, this condition is due to both excessive weight against chest wall, and defect in brain’s control for breathing. Due to the excessive amount of carbon dioxide in the blood and lower oxygen levels in blood can cause various health problems. This syndrome cannot be diagnosed on the history and a single examination, but it needs the demonstration of the daytime hypercapnia.
Your physician can confirm your OHS with obstructive sleep apnea symptoms, since people with OHS have high levels of carbon dioxide in blood when you are awake.
Returning to normal body weight is very important for the success of any kind of treatment.
If a person's skin or lips turn blue, it's usually caused by low blood oxygen levels or poor circulation.
With an account you can keep track of pages on the site and save them to this tab, which you can access on every page when you are logged in. Homoiotherms - These are organisms that that regulate their own body temperature internally. Poikilotherms - These are organisms that cannot regulate their own body temperature internally. Your Low Critical Temperature is about 27° C and at temperatures this low your metabolic rate changes. At your Lower Lethal Temperature (about 25° C) your system will collapse and you will probably die. Your High Critical Temperature is very high, but if it is reached your metabolic rate cannot decrease to lower it. Interesting point: Camels could sweat to stay cool in the desert, but they would lose too much water. Since these animals cannot control their own body temperature they rely on their behavior to seek out an area at their optimum temperature. Oats are low on the glycemic index, as they have a lot of fibre, which means that your body gets a steady stream–rather than a tide–of energy as carbohydrates gradually flow into your bloodstream. Caffeine is what makes coffee the morning cup of ambition that it is; it’s caffeine that blocks a chemical called adenosine that otherwise interferes with energy-boosting neurotransmitters.


Turkey contains an amino acid called tyrosine that, when digested, helps to manufacture the brain chemicals like dopamine. Chocolate can elevate your energy levels by way of certain bioactive compounds such as tyramine and phenylethylamine, says a study in the Journal of Food Science.
Dissolved oxygen analysis measures the amount of gaseous oxygen (O2) dissolved in an aqueous solution. The carotid sinus reflex protects blood flow to the brain, while the aortic reflex maintains blood pressure throughout the systemic circuit.
People who are suffering with obesity hypoventilation syndrome are usually have poor quality sleep, feeling tired due to sleeplessness. Generally treatment for obesity hypoventilation syndrome involves breathing assistance by using specific machinery. This can cause severe health problems; therefore following certain treatment plan is necessary.
All material provided on this website is provided for informational or educational purposes only. The hypothalamus has a thermo-regulatory centre and this detects the temperature of your blood. For instance, you can increase your temperature by doing exercise, or putting on extra layers of clothing. The cold temperature had slowed down her brain so the amount of oxygen in her blood was sufficient to prevent any brain damage. Instead, unless the temperature is very high (over 40°C), they stop sweating and allow their extremely tolerant tissues to get very hot.
Oats also contain the energizing–and stress-lowering–B vitamin family, which helps transform carbs into usable energy.
So having that morning cuppa isn’t going to hurt you and can actually make you more productive at work. They’re also a great source of fibre–which translates to a slow release of glucose–as well as B vitamins, iron, magnesium, potassium, zinc, calcium and copper. Bananas also provide a lot of potassium, an electrolyte that helps maintain normal nerve and muscle function.
Chocolate has also been claimed to improve anemia, awaken the appetite, aid in digestion, improve longevity, and increase sexual appetite.
Iron is a component of the haemoglobin in red blood cells and is found in the myoglobin in muscles and other tissues.
Saturated fats tend to make you lethargic by lowering the amount of circulating oxygen in your bloodstream.
This could be a sign of a life-threatening problem.See your GP or call NHS 111 if you have cyanosis that comes on very gradually, or affects just the fingers, hands, toes or feet. She was revived after her blood was passed through a heart bypass machine, warmed and then returned to her body. But remember, more than two cups of coffee per day can be counterproductive, since the initial high is followed by mild withdrawal symptoms, one of which is fatigue.
Unlike some nutrients, potassium isn’t stored by the body for long periods of time, so your potassium level can drop during times of stress or during strenuous exercise, when the nutrient is lost through excessive sweating.
Chocolate does contain sugar and caffeine along with fat and calories, so consume in moderation and, when possible, opt for dark chocolate, which has the fewest calories and the most antioxidants. When iron levels are inadequate, the cells in your body slowly suffocate from lack of oxygen and burn carbohydrates inefficiently. Monounsaturated fats such as almonds provide essential fatty acids, known as omega-3s and omega-6s,that produce an alert mental state. Magnesium also helps in the release of energy by transferring the key phosphate molecule to adenosine triphosphate, the explosive energy source you use when you lift weights. At midday they will lie in the shade, and at night they will lie in a crevice or burrow so that their immediate atmosphere is warm.
Also, be sure to drink more water when drinking coffee, as caffeine acts as a mild diuretic.
When you’re dehydrated, your cells receive nutrients for energy less efficiently, and your body can’t properly expend heat through sweating. Consequently, you feel sluggish, can’t concentrate, and are exhausted after minimal effort.
Other healthy fats to include in your diet are avocados, seeds, nuts, olive oil, and canola oil.
Other low-fat dairy foods to make room for are low-fat cheese, skim milk, and low-fat cottage cheese.
Fish in waters containing excessive dissolved gases may suffer from "gas bubble disease"; however, this is a very rare occurrence. Cyanosis that just affects the hands, feet or limbsIf just the fingers, toes or limbs have turned blue and feel cold, it's known as "peripheral cyanosis".
The best solution is to eat small meals of energy-promoting foods several times throughout the day, rather than waiting and waiting until you’re ravenous and you gorge on a huge meal made up of all the wrong choices. As red meat is the most readily absorbed form of iron, treat yourself to a high-quality steak (skip the Quarter Pounder) once a week to maintain healthy iron stores. With that in mind, we offer you a roster of foods that will keep your batteries charged, ready and rearing for your Kiama Group Fitness program and avoid the dreaded mid arvo crash!



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