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FEEBACK LOOPS, acts to bring factor back to homeostasis, stressor causes…
FEEBACK LOOPS
Homeostasis
- an organisms ability to maintain a stable internal environment
relies on feedback
controller
- brain (usually hypothalamus)
response
- physiological or behavioural
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influenced by environment
- biotic and abiotic factors
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membrane change permeability
- allows substances to move for equlibirum
metabolic pathways
- need homeostasis for effective cellular respiration
hormonal (endocrine) regulatory system
- change in metabolic activity (physiological responses)
- involuntary
STIMULUS causes hormone production
- chemical messengers (hormones) are then secreted into the bloodstream
received by receptors on target cells
- the binding of hormone and receptor triggers the response
- RECEPTOR
parts of the brain control when hormone should stop/start being released - detects the levels of substances
- hypothalamus, pituitary gland, medulla
- CONTROL
effectors (glands/cells/organds)
metabolic response (physiological)
-
long lasting as it circulates bloodstream
nervous regulatory system
- causes muscles to contract or glands to secrete
- voluntary or involuntary
sensory RECEPTORS (sense organs) detect STIMULUS
- electrochemical impulses are then transmitted to CNS via neurones (nerve cells)
central nervous system, CNS (brain and spinal cord)
effectors (muscles/glands)
fast, short term response
specific as nervous system acts as a signalling network via nerves
- impulses can be directly transmitted to target tissue
Postive
- mechanisms act to amplify a physiological response for an outcome
(moves away from a set point)
factor within normal range
Positive feedback causes large deviation from steady levels
-
Negative
- mechanisms act to stabilise the body back to a steady state
- induces a counter response
(moves towards a set point)
factor within normal range
Receptors detect stress (stimulus) --> corrective mechanisms activated
stimulus --> effector --> response
Factor back at optimum
Receptors detect stress (stimulus) --> corrective mechanisms activated
stimulus --> effector --> response
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