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61 Cards in this Set
- Front
- Back
internal environment
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fluid that surrounds the cells inside the body, including fluid in the bloodstream that surrounds blood cells; synonymous with extracellular fluid
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absorption
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In GI tract, the water, inorganic salts, and nutrients obtained from digested food are transported from the lumen to the bloodstream
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secretion
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in aid of digestion of food, the stomach uses materials from the blood to produce acids and proteins that are then transported into the lumen.
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filtration
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Happens in kidneys
fluid from bloodstream enters tubules. |
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Reabsorption
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fluid travel along tubules, and needed materials (H2O, inorganic salts, and nutrients) are selectively transported back into the bloodstream.
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Secretion
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At the same time as reabsorption, unneeded materials are selectively transported from the bloodstream into tubules.
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Excretion
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fluid that reaches the end of the tubules make up the urine which elminated from body.
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water
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What's the most abdundant substance in the body?
acts as a solvent w/solutes. |
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solutes
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inorganic ions
sugars amino acids Large molecules (proteins) |
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cell membranes
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ICF and ECF are separated by ____ _______.
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ICF
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proteins and potassium
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ECF
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few proteins
high sodium |
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Homeostasis
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maintenance of CONSTANT conditions in the internal environment
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Total body water (TBW)
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the total volume of fluid enclosed within the outer epithelial layer. Includes water that is found inside cells (ICF) and outside cells (ECF).
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Intracellular fluid (ICF)
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fluid inside cells
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ECF
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Fluid outside cells
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Plasma
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in blood
noncellular part of the blood rich in proteins |
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Interstitial fluid (ISF)
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The portion that is present OUTSIDE the blood and that bathes most of the cells in the body
few proteins |
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Capillaries
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smallest and most numerous blood vessels
highly permeable to most solutes except proteins. |
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Homeostatic regulatory mechanisms
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mechanism works to resist changes in the internal environment
has it's limitations even when it's undamaged by disease or trauma and is functioning normally. |
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Negative Feedback
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Homeostatic regulatory mechanisms follow same pattern
if regulated variable increases, the system responds by making it decrease. if it decrease, it responds to make it increase work to resist changes in the internal environment |
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Regulated variable
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something that must stay within narrow limits.
ex. Body temp., Potassium, sodium, and calcium. kept constant by homeostatic regulatory mechanisms |
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Set point
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Homeostatic regulatory mechanisms that make adjustments only when they DETECT a difference btwn. the actual value of the regulated variable and the normal "desired" value.
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Error signal
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Any difference btwn. the actual value and the set point sets off an _____ ______.
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Sensors
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cells that are sensitive to the variable in question.
This is the way that Homeostatic regulatory mechanisms can detect regulated variable. |
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Chemoreceptors
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sensitive to concentrations of oxygen and carbon dioxide in the blood
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Thermoreceptors
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sensitive to temperature
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Integrating center
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often a particular set of neural circuits in the brain
compares the regulated variable variable to the set point and plans the right response |
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input
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Sensors relay signal to integrating center
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output
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Integrating center relays signals to the cells, tissues, or organs that bring about the final response.
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Thermoregulatory center
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the region responsible for temp. regulation
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Positive feedback
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the response of the system goes in the same direction as the change that sets it in motion.
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LH surge
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triggers ovulation
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Thermoregulation
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utilization of feedback mechanisms to maintain normal body temp.
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hypothermia
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Prolonged exposure to very cold temps can cause body temp to fall below the set point
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Hyperthermia
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overextertion or exposure to very high environmental temps can cause body temp to rise above the set point.
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Homeothermic
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humans and other mammals are less affected by changes in the ambient temp because they have the ability to maintain their body temp within a fairly narrow range
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Poikilothermic
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animals and mammals who are not homeothermic.
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heat loss mechanisms
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radiation
conduction evaporation |
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Radiation
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transfer of thermal energy in the form of electromagnetic waves
when object is warmer than its surroundings, it absorbs and loses heat if an object is cooler than it surroundings, it absorbs more energy than it emits and gains heat. ex. heat from fire |
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Conduction
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transfer of thermal energy btwn. objects that are in direct contact with each other.
touching something cold can make you feel cold |
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Evaporation
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the process that converts it from liquid form to gaseous form absorbs thermal energy.
ex. takes place on skin, in lungs and mouth more water evaporates which carries away more thermal energy. |
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Insensible water loss
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happens in skin, lungs, and mouth on a continual basis without your being aware of it.
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Sweat
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a salt-containing solution secreted by numerous small sweat glands in the skin.
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Convection
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the transfer of heat from one place to another by moving gas or liquid, contributes to heat loss on a windy day.
under still conditions, the air that is closer to your skin warm up due to the absorption of heat from the body's surface (forms a "blanket" around body) warmer air slows down heat loss when windy the "blanket" is reduced which leads to heat loss |
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hypothalamus
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a region located in the base of the brain just above the pit. gland.
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central thermoreceptors
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send input to brain center (brain, spinal cord) and monitor the temp. from inside body (core temp.)
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Core temperature
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temp deep within the body
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Peripheral receptors
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located in the skin whose temp is usually well below core temp and is more variable.
enables us to sense the temp of the environment |
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effectors that vary the rate of heat production or loss
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sweat glands
blood vessels in skin skeletal muscle |
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sweat glands
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control evaporative heat loss increasing or decreasing sweat production
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Blood vessels in the skin
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which control conductive and radiative heat lossby increasing or decreasing blood flow to the skin
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skeletal muscle
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which control heat production through shivering
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shivering
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rapid bursts of involuntary contractions that generate heat as a metabolic by product
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thermoneutral zone
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outside temp is within a narrow range (25 to 30 C)
blood flow to skin can make normal adjustments till core temp is normal |
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thermoregulatory centers
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When core temps change ________ ______ send signals to effectors.
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Negative feedback response to core temperature
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1. Decrease sweat production
2. Decrease blood flow to skin 3. Stimulate shivering |
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Fever
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elevation of body temp usually during illness. Not from failure of thermoregulatory system. Set points not being reset cause fever.
bacterial & viral infections stimulate WBC's to proliferate chemical substances which rise set point, and act as pyrogens. |
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Chills
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↑ muscle activity used to ↑ body temp
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Sweats
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↑ evaporative cooling to ↓ body temp
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pyrogens
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fever inducers
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