homeostasis & response xoxo Flashcards
define homeostasis
maintenance of a constant internal environment
what conditions need to be controlled in the body, how & why
water content - absorbed from food and drink, lost via sweat and urine -maintain con gradient for osmosis to, prevent cell damage. temp - behaviour - enzymes work efficiently. ion content - absorbed from food, lost through sweating - needed in body. blood glucose levels - controlled through food intake & amount of respiration - glucose is necessary for respiration. co2 conc in blood - controlled through rate of respiration and breathing faster - is toxic and can damage cells
automatic control system pattern
stimulus -> sensory neurone -> receptor -> sensory neurone -> coordination centre (relay neurone) -> motor neurone -> effector
define stimiulus
change in environment
define receptor
cell that detects stimulus
define coordination centre
part of CNS which coordinates response
define effector
muscle/gland which brings about response
define response
what happens from effector
two main parts of nervous system
CNA and peripheral nervous system
what is in the CNS
brain, spinal cord
what is in the PNS
sensory (sensory nerves) and motor (motor nerves)
sensory neurone
transmits impulses from receptor cell to CNS
Relay neurone
found in CNS - transmits impulses from sensory neurone to motor neurone
Motot neurone
transmits impulses from CNS to effector
how does information pass a synapse
electrical impulse is turned into neurotransmitter - moves into synapse from pre-synaptic membrane - diffuses down conc gradient - fits into receptor on post-synaptic membrane - triggers impulse in next neurone
