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25 Cards in this Set
- Front
- Back
Define thermoregulation |
Maintaining body temperature by losing the same amount of heat that's gained |
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Why is body temperature higher than the external environment? |
Metabolic activity produces a lot of heat |
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Why does heat need to be removed? |
Highly increased temperature leads to nerve malfunction, a change in protein structures, and even death |
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Define dynamic equilibrium |
Some factors contribute to heat gain, others to heat loss |
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How does temperature variation occur? |
Activity, external temperature changes, body temperature cycle, menstruation, convection, conduction, radiation, evaporation of water from skin, breathing, urination and defecation |
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Define metabolic rate |
Rate of energy release |
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Which factors affect metabolic rate? |
1. Increased body temp of 1 deg. Increases rate by 10% 2. Stress - ANS and release of noradrenaline 3. Muscular activity during respiration |
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How is energy released? |
By the anabolism of lipids, proteins, and carbs during cell respiration |
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How is most energy used? |
1. Released as heat 2. Energy for muscles 3. Energy for active transport |
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Define peripheral thermoreceptors |
Heat receptors in the skin and mucous membranes that sense the external temperature. There are cold and hot receptors. |
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Define central thermoreceptors |
Heat receptors in the hypothalamus, abdominal organs, and spinal cord that sense internal temperature |
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What special role do the thermo receptors in the hypothalamus play? |
They regulate body temp by responding to stimuli with nerve impulses. They are connected to all other thermo receptors and are stimulated to respond by peripheral receptors. |
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What happens when cold receptors in the hypothalamus are stimulated? |
Heat conservation and production are initiated |
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What happens when heat receptors in the hypothalamus are stimulated? |
Increased heat loss and reduced conservation |
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Name the ways that heat can be lost |
1. Conduction 2. Convection 3. Radiation 4. Evaporation |
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Define radiation |
The heat generated in the body is given off to the surrounding atmosphere |
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Define conduction |
When heat is lost to something that is contacting the body |
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Define convection |
Heat loss caused by motion |
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Define evaporation |
When sweat/moisture evaporates from skin, heat is taken with it |
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Why do blood vessels near the surface of the skin control the level of blood flow? |
1. Change level of heat loss for homeostasis 2. Keep core body temp constant |
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Define sweating |
Active secretion of fluid by the sweat glands and periodic contraction of the cells surrounding the ducts to pump the sweat to the skin's surface |
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Why does sweating occur? |
It occurs when heat still needs to be lost despite full vasodilation |
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Define sweat |
Water containing solutes that allows for heat loss |
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Which solutes are found in sweat? |
Sodium chloride, urea, lactic acid, potassium ions |
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What physical reaction is there to a cold stimulus from the external environment? |
1. Cold receptors in skin send a message to hypothalamus 2. Hypothalamus sends impulses to reduce heat loss 3. Physiological and behavioural responses may occur |