Any change in the environment that causes a response
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Response
A change in the behaviour or physiology as a result of a change in the environment
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Homeostasis
the maintenance of a constant internal environment despite changes to the external environment
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Negative fedback
a process that brings about the reversal of a change in conditions, ensuring a constand state is maintained
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Positive feedback
process that increases a change detected by receptors can be harmful and does not lea dto homeostasis
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Ectotherm
Organism that relies on external source of heat to regulate body temperature
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endotherm
organism that used internal heat from metabolism to maintain body temperature
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polarised
membrane with a potential difference across it. this is the resting potential
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depolarisation
loss of polarisation across membrane.
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generator potential
small depolarisation caused by Na+ entering cell
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Action potential
achieved when depolarisation reaches +40mV. all or nothing response.
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Voltage-gated channel
Channels in membrane that allow passage of ions. can open and close depending on polarity.
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threshold potential
potential difference about -50mV. if this is not reached, then action potential is not made
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Local current
movement of ions along a neurone. increased conc leads to diffusion to next region.
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Saltatory conduction
action potential jumps between nodes of Ranvier
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Neurotransmitter
chemical used to pass impulse across synapse
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Synaptic knob
Swelling at the end of a pre-synatic neurone
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Summation
the way several potential changes can combine to produce one larger potential difference.
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Hormone
molecules released by endocrine glands into the blood. They act as messengers
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Endocrine gland
gland secreting hormones into blood
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Exocrine gland
gland secreting into a duct
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target cell
a cell with the specific receptor for a hormone
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Adenyl Cyclase
Enzyme associated with many hormones.
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First messenger
Hormone that transmits signal around body
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Second messenger
cAMP, transmits the signal into the cell
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Pancreatic duct
Dust collecting secretions from exocrine glands in pancreas
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Islets of langahans
small patches on tissue tht have endocrine function. made up of alpha and beta cells.
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Diabetes Mellitus
blood glucose can't be controlled
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Hyperglycaemia
blood glucose is too high
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Hypoglycaemia
blood glucose is too low
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Myogenic
muscle that can contract on its own
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Medulla Oblongata
Base of brain stem, responsible for unconsious functions such as heart rate.
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cardiovascular centre
region in Medulla Oblongata that recieves sensory input about activity levels, CO2 conc and blood pressure. sends impulse to SAN to alter frequency of wave of exitation.
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Other cards in this set
Card 2
Front
A change in the behaviour or physiology as a result of a change in the environment
Back
Response
Card 3
Front
the maintenance of a constant internal environment despite changes to the external environment
Back
Card 4
Front
a process that brings about the reversal of a change in conditions, ensuring a constand state is maintained
Back
Card 5
Front
process that increases a change detected by receptors can be harmful and does not lea dto homeostasis
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