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Section 9.4: Transport Systems and Homeostasis Osmotic Balance: Lymphatic Circulation (p.313) lymphatic circulatory system is a network of glands and vessels that extends throughout your body the fluid, lymph, is either colourless or pale yellow and is much like plasma when blood circulates, some of the fluid escapes to become interstitial fluid, the fluid that bathes the cells much of this fluid is then absorbed into the lymphatic circulatory system both the lymphatic and cardiovascular circulatory systems join many times lymphocytes, white blood cells, are produced in the lymph nodes when you are sick, your lymph nodes often swell the flow of lymph depends almost entirely on the movement of muscles outside the circulatory system – squeezing, like how blood moves in veins Temperature Regulation birds and mammals are homeotherms, which means they keep their bodies at a regular temperature cold-blooded animals are poikilotherms, which means their body temperature fluctuates with the environment our normal body temperature is approx. 37.5 oC behavioral such as putting on more clothes when it is cold outside it is the circulatory system that plays the major role in temperature control blood coming to the skin form the interior of the body is usually warmer than the skin when the body needs to conserve heat, the blood vessels close to the skin constrict to limit the blood supply and thus heat loss when the body needs to release heat, these blood vessels dilate under the skins surface and you feel flush the constriction of blood vessels is called vasoconstriction and the dilation of blood vessels is called vasodilatation your body uses a countercurrent heat exchange system to help maintain normal body temperature deep arteries and veins leaving and entering the body lie side by side as the arteries leave the body, they are warmer and their heat will follow the heat gradient to the veins returning from the extremities this way, the venous blood gets warmed, and the arterial blood cools downs Blood Pressure when blood pressure goes up, stretch receptors in the arterial walls are stimulated at the same time chemoreceptors detect changes in concentration of O2 and CO2 these both stimulate the medulla oblongata to slow the heart rate the highest pressure in the cardiac cycle is the contraction of the ventricles or systolic pressure the lowest pressure is just before the ventricles contract or diastolic pressure blood pressure is measure in mm Hg and “normal” blood pressure is 120 mm Hg (systolic) over 80 mm Hg (diastolic) 120/80 Blood Pressure Risks hypertension, or high blood pressure, is associated with a number of heath risks including hear disease (diastolic of 90or more) causes are genetics, age, exercise, smoking, diet and obesity arteriosclerosis is a condition in which cholesterol or other fatty substances become deposited under the inside lining of an artery this is mainly caused by lifestyle but genetics can have a contributing factor this causes a narrowing of the arteries which can trigger a clot this clot, known as an embolism, may make its way to the heart causing a heart attack, the lung causing pulmonary embolism, the brain causing a stroke or to an extremity causing thrombosis (tissue will die (gangrene)) angioplasty is where a clogged artery is unblocked using a small balloon coronary bypass surgery is when veins taken from other parts of the body are grated onto the arteries of the heart so the blood can bypass an obstruction Section 9.4: Transport Systems and Homeostasis Osmotic Balance: Lymphatic Circulation (p.313) lymphatic circulatory system is a network of glands and vessels that extends throughout your body the fluid, lymph, is either colourless or pale yellow and is much like plasma when blood circulates, some of the fluid escapes to become interstitial fluid, the fluid that bathes the cells much of this fluid is then absorbed into the lymphatic circulatory system both the lymphatic and cardiovascular circulatory systems join many times lymphocytes, white blood cells, are produced in the lymph nodes when you are sick, your lymph nodes often swell the flow of lymph depends almost entirely on the movement of muscles outside the circulatory system – squeezing, like how blood moves in veins Temperature Regulation birds and mammals are homeotherms, which means they keep their bodies at a regular temperature cold-blooded animals are poikilotherms, which means their body temperature fluctuates with the environment our normal body temperature is approx. 37.5 oC behavioral such as putting on more clothes when it is cold outside it is the circulatory system that plays the major role in temperature control blood coming to the skin form the interior of the body is usually warmer than the skin when the body needs to conserve heat, the blood vessels close to the skin constrict to limit the blood supply and thus heat loss when the body needs to release heat, these blood vessels dilate under the skins surface and you feel flush the constriction of blood vessels is called vasoconstriction and the dilation of blood vessels is called vasodilatation your body uses a countercurrent heat exchange system to help maintain normal body temperature deep arteries and veins leaving and entering the body lie side by side as the arteries leave the body, they are warmer and their heat will follow the heat gradient to the veins returning from the extremities this way, the venous blood gets warmed, and the arterial blood cools downs Blood Pressure when blood pressure goes up, stretch receptors in the arterial walls are stimulated at the same time chemoreceptors detect changes in concentration of O2 and CO2 these both stimulate the medulla oblongata to slow the heart rate the highest pressure in the cardiac cycle is the contraction of the ventricles or systolic pressure the lowest pressure is just before the ventricles contract or diastolic pressure blood pressure is measure in mm Hg and “normal” blood pressure is 120 mm Hg (systolic) over 80 mm Hg (diastolic) 120/80 Blood Pressure Risks hypertension, or high blood pressure, is associated with a number of heath risks including hear disease (diastolic of 90or more) causes are genetics, age, exercise, smoking, diet and obesity arteriosclerosis is a condition in which cholesterol or other fatty substances become deposited under the inside lining of an artery this is mainly caused by lifestyle but genetics can have a contributing factor this causes a narrowing of the arteries which can trigger a clot this clot, known as an embolism, may make its way to the heart causing a heart attack, the lung causing pulmonary embolism, the brain causing a stroke or to an extremity causing thrombosis (tissue will die (gangrene)) angioplasty is where a clogged artery is unblocked using a small balloon coronary bypass surgery is when veins taken from other parts of the body are grated onto the arteries of the heart so the blood can bypass an obstruction
