Why do multicellular organisms need communication systems?
so they can respond to internal and environmental changes
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How do multicellular organisms communication systems work?
uses cell signalling methods to coordinate the activities of different organs
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How do animal cells communicate?
through the nervous system and the endocrine system
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What is homeostasis?
maintenance of near constant conditions in the body
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What is negative feedback?
way in which changes in a factor stimulate corrective actions to restore the factor to its set point
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What is positive feedback?
response to change by increasing the original factor changing
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What is a set point?
the value of any physiological factor that the body tries to keep constant
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what happens when changes are detected?
receptors communicate with central control, response is then carried out by effector cells
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What are effector cells? where are they found?
carry out corrective actions / tissue and organs
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What is an endotherm?
maintain a near content core body temp independent of external surroundings by a mean of homeostasis
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What changes are made when an endotherms internal/external temperature changes?
sweat glands increase sweating (latent heat of vaporisation) / Vasodilation / liver decreases rate of metabolism, less heat produced
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What is vasodilation? What does it do?
arterioles in the skin dilate, more blood flows to skin capillaries / loss of heat by convection and radiatin
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What internal changes are made when an endotherm's internal/external temperature decreases?
goosebumps / sweat glands decrease sweating / vasoconstriction / liver increases rate of metabolism - brown adipose tissue respired// skeletal muscles shiver to increase rate of respiration but is not effective over extend time period
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What behavioural adaptions do endotherms have in warm weather?
move into shade or hide in burrow / orientate body to decrease exposed area to sun / remain inactive / spread out limbs to increase SA
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What behavioural adaptations do endotherms have in cold weather?
move into sunlight / orientate body to increase surface area exposed to sun / move about to generate heat in muscles /
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How do endotherms monitor core temperature?
hypothalamus monitors blood temp / sends signals to defectors
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How do endotherms monitor external temperature?
peripheral temp receptors monitor the extremities / info fed to thermoregulatory centre / if temp change signal sent to brain, initiate behavioural mechanisms etc.
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What are the advantages of being endotherms?
constant temp/ active in cold temps/ can inhabit colder countries
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What are the disadvantages of being endotherms?
lost of energy required to keep temp constant / more food needed / less energy from food goes into growth
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What is an ectotherm? give some examples
animal which relies on the external environment for temp control / amphibians, reptiles, invertebrates and most fish
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What behaviour adaptations do ectotherms have?
bask - expose skin to suns radiation / orientate body to or form sun / hide in burrow/ alter body shape for SA/ increase breathing rate (pant) to increase water evap
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What are the advantages of being an ectotherm?
use less food in respiration / need less food / can use more energy from food for growth
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What are the disadvantages of being an ectotherm?
less active in cooler temps/ may not be capable of activity in winter sue to the need to hibernate
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Other cards in this set
Card 2
Front
How do multicellular organisms communication systems work?
Back
uses cell signalling methods to coordinate the activities of different organs
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