Term
| These generate their own internal body heat and do not rely on the energy of sunlight in this regard. |
|
Definition
|
|
Term
| These are capable of maintaining body temp within narrow limits despite wide fluctuations in ambient temps. Humans fall into this category. |
|
Definition
|
|
Term
| Large core temperature elevations can cause what 2 things? |
|
Definition
Nerve malfunction
Protein denaturation |
|
|
Term
| The absolute limit for survival |
|
Definition
106 degrees F
(21 degrees C) |
|
|
Term
| Core body temperature remains very constant, within 1 degree F, except when a person develops a febrile illness. A nude person can be exposed to dry air temps from _ to _ and still maintain an almost contant body temp |
|
Definition
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|
Term
| Oral temperature normal values |
|
Definition
97-99.5 degrees F
.5 - 1 C less than rectal |
|
|
Term
| An estimate of internal temperature (core body temp): 98-98.6 degrees F |
|
Definition
|
|
Term
| Internal temperature varies several degrees in response to what 2 things? |
|
Definition
Activity patterns
Changes in external temps |
|
|
Term
| Circadian fluctuation of about 1 degree C, _ during the night and _ during the day |
|
Definition
|
|
Term
| Women experience a higher body temp during when? |
|
Definition
| 2nd half of menstrual cycle due to effects of progesterone |
|
|
Term
|
Definition
|
|
Term
| When the rate of heat production in the body is greater than the rate at which heat is being lost, heat builds up in the body and body temperature __ |
|
Definition
|
|
Term
| When heat loss is greater than the rate of heat production in the body, body temperature __ |
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Definition
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|
Term
| The process by which surfaces of all objects constantly emit heat in the form of electromagnetic waves. |
|
Definition
|
|
Term
| The rate of emission is determined by teperature of the radiating surface; if body is warmer than various surfaces in the environment, net heat is lost from the body. |
|
Definition
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|
Term
| The rate of emission is dependent upon temperature difference. The body can gain heat by absorbing electromagnetic energy emitted by the sun. |
|
Definition
|
|
Term
| A loss of gain of heat by transfer of thermal energy during collisions between adjacent molecules. Body surface loses or gains heat by __ through direct contact with cooler or warmer substances, including air and water. |
|
Definition
|
|
Term
| __ is a better conductor than air so more heat is lost from the body in _ than air. |
|
Definition
|
|
Term
| __ is not a perfect insulator so temperature is between the external environment and core. |
|
Definition
|
|
Term
| Functions as a variable regulator of heat exchange in blood flow. The more blood reaches it from the core, the more closely it's temperature approaches that of the core. Blood vessels can carry heat to it to be lost to the external environment. |
|
Definition
|
|
Term
| Name 3 behavioral mechanisms for altering heat loss |
|
Definition
1. Changes in surface area
2. Changes in clothing
3. Choice of surroundings |
|
|
Term
| The amount of energy it takes to change temperature |
|
Definition
|
|
Term
| Conductive heat loss or gain is aided by movement of the air or water next to the body |
|
Definition
|
|
Term
| Give an example of convection |
|
Definition
| Air next to the body is heated by conduction |
|
|
Term
| Warm air is less dense, rises, heat is carried away from the body, cool air replaces it, follows the same pattern |
|
Definition
|
|
Term
| Aids conduction by continuously maintaining cool air |
|
Definition
|
|
Term
| Explain the cooling effect of wind |
|
Definition
| When body is exposed o wind, the layer of air immediately next to the skin is replaced by new air more rapidly than normal and heat loss by convection increases accordingly |
|
|
Term
| Water has a specific heat __ than air |
|
Definition
|
|
Term
| Water adjacent to skin can absorb __ quantities of heat than air |
|
Definition
|
|
Term
| __ __ in water is greater than air so it is impossible for the body to heat a thin layer of water next to the body to form an "insulator zone" as occurs in the air. |
|
Definition
|
|
Term
| Rate of heat loss to water is usually many times greater than the rate of heat loss to __ |
|
Definition
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|
Term
| Clothing entraps air next to skin in the weave of cloth, thereby increasing thickness of __ __ of air adjacent to skin and also decreasing he flow of convection air currents; rate of heat loss from the body is greatly depressed. |
|
Definition
|
|
Term
| The effectiveness of clothing is almost completely lost when it becomes wet because the high conductivity of water increases the rate of heat transmission thru cloth __ fold or more |
|
Definition
|
|
Term
| __ of water from skin and membranes lining respiratory tract causes loss of body heat |
|
Definition
|
|
Term
| As long as skin temperature is greater than the temperature of the surroundings, heat can be lost by what 2 mechanisms? |
|
Definition
|
|
Term
| When the temperature of the surroundings becomes greater than that of the skin, the only means by which the body can rid itself of heat is by __ |
|
Definition
|
|
Term
| __ is required to transform water from liquid to gas, the heat required is conducted from surface and cools it |
|
Definition
|
|
Term
| Insensible water loss: Passive water loss occurs in 2 ways. |
|
Definition
1. Loss of water by diffusion thru skin, even in absence of sweating
2. Loss from the respiratry lining during expiration |
|
|
Term
| Requires active secretion of fluid by sweat glands and its extrusion into ducts that carry it to the skin surface |
|
Definition
|
|
Term
| Production of sweat stimulated by sympathetic nerves to glands. Sweat must evaporate in order to exert its cooling effect. Evaporation rate determined by the water vapor concentration of the air which is known as __ |
|
Definition
|
|
Term
| If you increase humidity, then you __ evaporation of sweat |
|
Definition
|
|
Term
| The principle by-product of metabolism |
|
Definition
|
|
Term
| Name 5 factors that determine the rate of heat production |
|
Definition
1. Basal rate of metabolism of all the cells of the body
2. Extra rate of metabolism caused by ms activity, including ms contractions caused by shivering
3. Extra metabolism caused by the effect of thyroxine on the cells, epinephrine, NE, and symp stimulation of cells
4. Extra metabolism needed for digestion, absorption, and food storage
5. Extra metabolism caused by increased chemical activity in the cells themselves |
|
|
Term
| Rate of heat loss is determined by what 2 things? |
|
Definition
1. How rapidly heat can be conducted from where it is produced in the body core to the skin
2. How rapidly heat can be transferred from the skin to the surroundings |
|
|
Term
| Continuously disrupted by metabolic rate or changes in the external environment |
|
Definition
|
|
Term
| Body temperature is almost entirely regulated by what? |
|
Definition
| Nervous feedback mechanisms |
|
|
Term
| Almost all nervous feedback mechanisms operate thru temperature-regulating centers located where? |
|
Definition
|
|
Term
| Detect change and initiate reflexes that restore temp to normal. |
|
Definition
|
|
Term
| Provided by sympathetic nerves to the sweat glands, skin arterioles, adrenal medulla, and motor neurons to skeletal muscles. |
|
Definition
| Output to reflexes initiated by thermoreceptors |
|
|
Term
| Found in the skin and provide feedforward information |
|
Definition
| Peripheral Thermoreceptors |
|
|
Term
| __ receptors in the skin respond to cold or warmth |
|
Definition
|
|
Term
| There are __X cold receptors as their are warmth receptors. Therefore, peripheral detection of temperature mainly concerns the detection of cool or cold temps instead of warm |
|
Definition
|
|
Term
| When skin is chilled, immediate reflex effects are invoked and begin to increase body temp in what 3 ways? |
|
Definition
1. Providing strong stimulus to begin shivering
2. Inhibiting the process of sweating if already occurring
3. Promoting skin vasoconstriction to diminish loss of heat thru the skin |
|
|
Term
| Shivering _ heat production |
|
Definition
|
|
Term
| Sweating and skin vasoconstriction __ heat loss |
|
Definition
|
|
Term
| Provides essential feedback component of the reflexes. |
|
Definition
|
|
Term
| Primarily found in the spinal cord, abdominal viscera, and the great veins of upper abdomen and thorax |
|
Definition
|
|
Term
| Exposed to core body temp, not surface temp |
|
Definition
|
|
Term
| The primary integrator of reflexes for body temp |
|
Definition
|
|
Term
| Both skin and deep receptors are likely most concerned with preventing what? |
|
Definition
|
|
Term
| "heat sensing" and "cold sensing" neurons are located in the ___ area and function as temperature sensors. |
|
Definition
|
|
Term
| Both types of neurons (heat and cold sensing) increase their __ __ when the core temp changes - either increase temp (heat sensing)or decrease temp (cold sensing) |
|
Definition
|
|
Term
| When the __ area is heated, skin all over the body breaks out in sweat, whereas the skin blood vessels dilate. This is an immediate reaction and excess body heat is inhibited. |
|
Definition
|
|
Term
| The mediator for the temp-sensing neurons |
|
Definition
|
|
Term
| Integrates the central and peripheral temperature sensory signals from thermoreceptors |
|
Definition
|
|
Term
| Sensory signals from thermoreceptors and the anterior preoptic area stimulate the posterior hypothalamus at the level of the what? |
|
Definition
|
|
Term
| At the level of the __ __, the signals are combined and processed to control heat-conserving and heat-producing reactions in the body. |
|
Definition
|
|
Term
| Can increase heat loss or decrease heat production |
|
Definition
| Temp-decreasing mechanism |
|
|
Term
| Vasodilation of skin blood vessels in most areas of the body are caused by what? |
|
Definition
| Inhibition of sympathetic centers in the posterior hypothalamus that cause vasoconstriction |
|
|
Term
| Name 3 temp-decreasing mechanisms |
|
Definition
1. Vasodilation
2. Sweating
3. Decrease in heat production |
|
|
Term
| Can decrease heat loss or increase heat production |
|
Definition
|
|
Term
| Caused by stimulation of the posterior hypothalamic sympathetic centers |
|
Definition
| Skin vasoconstriction throughout the body |
|
|
Term
| Sympathetic stimulation causes the arrector pili muscles attached to hair follicles to contract, bringing the hair upright. This allows them to trap a thick layer of "insulator air" next to the skin, so transfer of heat is depressed. |
|
Definition
|
|
Term
| Name 3 ways to increase thermogenesis |
|
Definition
1. Hypothalamic Stimulation of shivering
2. Sympathetic "chemical excitation of heat production"
3. Increased thyroxine output |
|
|
Term
| An area called the __ __ center controls shivering |
|
Definition
|
|
Term
| Normally inhibited by signals of heat from the anterior pre-optic area, but is excited by cold signals from the skin and spinal cord. |
|
Definition
|
|
Term
| Caused by increased tone of skeletal muscle throughout the body by facilitating activity of ventral motor neurons. When the tone rises above a certain threshold, shaking of the muscle begins |
|
Definition
|
|
Term
| During shivering, efferent motor nerves to skeletal muscle are influenced by the hypothalamus, no external work is performed, virtually all the energy liberated by the metabolic machinery appears as internal heat.This process is called what? |
|
Definition
|
|
Term
| An increase in metabolic activity caused by an increased adrenal secretion of epi and increase sympathetic activity to adipose tissue, some contribution by thyroid hormone. Minimal, rarely present in adults. Occurs in infants whose shivering mechanism less efficient; product is heat. |
|
Definition
| Nonshivering Thermogenesis |
|
|
Term
| Seen in newborn infants. Tissue is responsive to thyroid hormone, epi and SNS; contains large amounts of uncoupling proteins. Proteins uncouple oxidation from phosphorylation and make metabolism less efficient; product is heat. |
|
Definition
|
|
Term
| Cooling of anterior pre-optic area also increased production of what? |
|
Definition
| Thyrotropin Releasing Hormone (TRH) |
|
|
Term
| Where is TRH released from? |
|
Definition
|
|
Term
| TRH stimulates the release of what from the anterior pituitary gland? |
|
Definition
| TSH (Thyroid Stimulating Hormone) |
|
|
Term
| TSH stimulates the release of what by the thyroid gland? |
|
Definition
|
|
Term
| What increases the rate of cellular metabolism throughout the body |
|
Definition
|
|
Term
| An overactive thyroid gland, increses cellular metabolism and __ weight |
|
Definition
|
|
Term
| Is thyroxine output an immediate effect? |
|
Definition
| No, it requires several weeks of exposure to cold temps to make the thyroid gland hypertrophy and reach its new level of thyroxine secretion |
|
|
Term
| __ mechanisms regulating temp is a graded, progressive increase or decrease in activity |
|
Definition
|
|
Term
| Range of environmental temp (25-30 C) that blood flow alone can regulate. A person's ability to tolerate such temps above and below is determined by the humidity and by his or her maximal sweating rate. |
|
Definition
|
|
Term
| Changes in sweating onset, volume, and composition determine the ability to adapt to chronic high temps. |
|
Definition
|
|
Term
| An important change in the composition of sweat with temp acclimatization, namely, a significant reduction in salt concentration due to incresed secretion of aldosterone. |
|
Definition
|
|
Term
| Body temp that is above normal range. Can be caused by abnormalities in the brain itself or by toxic substances that affect the temp-regulating centers |
|
Definition
|
|
Term
| Name 3 main causes of fever. |
|
Definition
1. Temp regulation seriously impaired (106-114 F)
2. Heat stroke, brain lesion (105-116 F)
3. Febrile disease and hard exercise (99-104 F) |
|
|
Term
| Proteins, protein products, and other substances released from bacterial cell membranes can cause the set-point of the hypothalamic thermostat to rise |
|
Definition
|
|
Term
| When set-point of hypothalamic temp-regulating center becomes __ than normal, all mechanisms for raising body emp are brought into play, within a few hours, the body temp approached the new level |
|
Definition
|
|
Term
| __ released from bacteria pyrogens increase temp-regulating set-point. |
|
Definition
|
|
Term
| Leukocytes, macrophages, and lymphocytes digest bacteria and release what? |
|
Definition
|
|
Term
| Interleukin-1 is a cytokine released and immediately activates the processes to produce fever when it reaches the hypothalamus; it can increase in ___ minutes |
|
Definition
|
|
Term
| Can a hypothalamic tumor cause sever fever? |
|
Definition
|
|
Term
| When set-point of hypothalamic temp-control center is suddenly increased, body temp usually takes several hours to reach what? |
|
Definition
|
|
Term
| When the blood temp is less than the set-point which causes usual response to __ body temp |
|
Definition
|
|
Term
| Duing the period when blood temp is less than set-point, the person experiences ___ and feels extremely cold even thogh his body temp may already be above normal. |
|
Definition
|
|
Term
| When a person has chills, their skin becomes cold because of __ and shivering occurs. |
|
Definition
|
|
Term
| __ continues until the body temp reaches the hypothalamic set-point, the person no longer feels cold or hot. |
|
Definition
|
|
Term
| The factor that is causing the high temp it removed, set point of hypothalamic temp controller will be reduced |
|
Definition
|
|
Term
| Body temp is still high but the hypothalamus is attempting to regulate the temp to 98.6 F. This causes intense sweating and sudden development of hot skin becasue of vasodilation everywhere. |
|
Definition
|
|
Term
| The upper limit of air temp that one can stand depends to a great extent on whether the air is dry to wet. If dry and sufficient, convection air currents are flowing to promote rapid evaporation from body, a person can withstand several hours of air temp at 130 F. If air is 100% humidified or if the body is in water, body temp rises whenever the environmental temp rises above 94 F. |
|
Definition
|
|
Term
| When the body temperature rises into range of 105-108 F, person develops __ |
|
Definition
|
|
Term
| What are the symptoms of heatstroke? |
|
Definition
Dizziness
Abdominal Distress
Vomiting
Delirium
Loss of consciousness |
|
|
Term
| Symptoms of a heatstroke often exacerbate by a degree of __ __ from fluid and electrolyte loss in sweat. |
|
Definition
|
|
Term
| Abnormally high fever. Itself it is also damaging to body tissues, especially brain. Even a few minutes of very high body temp can be fatal. Immediate treatment of heatstroke by placing person in cold water bath is recommended. |
|
Definition
|
|
Term
| A person exposed to ice water for 20-30 minutes ordinarily dies because of heart standstill or fibrillation. Internal body temp will fall to about __F. If warmed rapidly by external heat, can be saved. |
|
Definition
|
|
Term
| Once body temp falls below __F, hypothalamus losses abililty to regulate temp; it is greatly impaired even at __F. |
|
Definition
|
|
Term
| __ heat production in each cell is depressed almost 2-fold for each 10degrees F decrease in body temp; sleepiness and coma can develop which depresses acivity of CNS heat control mechanisms and shivering. |
|
Definition
|
|
Term
| Freezing of body surfaces |
|
Definition
|
|
Term
| Can cause extensive formation of ice crystals in the cells resulting in permanent circulatory damage. |
|
Definition
|
|
Term
| Upon thawing __ can occurs and amputation may be necessary. |
|
Definition
|
|
Term
| Temp close to freezing paralyzes smooth ms in vascular wall and sudden __ occurs. |
|
Definition
|
|
Term
| Can help prevent frostbite by delivering warm blood to the skin, mechanism not developed well in humans. |
|
Definition
| Paralysis of smooth ms and sudden vasodilation |
|
|
Term
| Administration of strong sedative to depress reactivity of hypothalamic temp controller and then cooling the person with ice or cooling blankets until the temp falls |
|
Definition
|
|
Term
| Can be maintained below 90F for days to weeks. Used during heart surgery so the heart can be stopped artificially for many minutes at a time, will greatly depress cell metabolism so the cells can survive 30 minutes to more than 1 hour without blood flow during the surgical procedure. |
|
Definition
|
|
Term
| Almost all energy released by metabolism of nutrients is eventually converted into body heat during: |
|
Definition
| Conversion of nutrient energy to ms work |
|
|
Term
| 3 ways in which you can have conversion of nutrient energy into ms work. |
|
Definition
1. Overcoming viscous resistance to the movement of ms and joints
2. Ovecoming friction of the blood flowing thru the vessels
3. Other effects which convert ms contractile energy into heat |
|
|
Term
| __ consumption by the body can increase in a well-trained athelete |
|
Definition
|
|
Term
| The amount of heat liberated in the body is almost exactly proportional to what? |
|
Definition
|
|
Term
| Tremendous amounts of heat injected into internal body tissues when performing endurance athletic events. During a hot and humid day a __ can easily develop in the athlete. |
|
Definition
|
|
Term
| In 1 hour of exercise as much as __ lbs of weight loss can occur due to sweat |
|
Definition
|
|
Term
| A __% decrease in body weight decreases performance and __% decrease in body weight can cause muscle cramps and nausea. It is essential to replace the fluids lost |
|
Definition
|
|
Term
| Name 3 things that sweat contains |
|
Definition
|
|
Term
| If a person acclimates to the heat by progressiv increase in athletic exposure over a period of 1-2 weeks, what other 2 things acclimate? |
|
Definition
|
|
Term
| __ __ acclimation is due to increased aldosterone secretion by the arenal cortex. Aldosterone increases reabsoption of sodium chloride from the sweat before it is secreted onto the skin. |
|
Definition
|
|
Term
| __ loss results from increased secretion of aldosterone during heat acclimatization, which increases loss of potassium in the urine |
|
Definition
|
|
Term
| Supplemental fluids contain properly proportioned amount of what 2 things? |
|
Definition
|
|
