B5- homeostasis and response Flashcards
what is homeostasis?
the maintenance and regulation of your bodies internal conditions in response to a change in the environment.
your automatic control system keeps you internal environment stable by using a mechanism called?
negative feedback- which controls the levels of conditions including: concentration of co2 body temp blood sugar/glucose levels water content
what do receptors do?
receptors detect a stimulus (change in the environment)
what does your coordination centre do
receives information and processes it, then organises a response.
what is an effector?
the effector produces a response to a stimulus.
e.g a muscle contracts to move the arm
what does the nervous system ensure?
that humans can react to their surroundings and coordinate their behaviour.
what are two examples of effectors and how do they respond?
muscle- contract
glands- secrete hormones
what do synapses do?
allow signals to be transferred by chemicals between neurons.
what are reflexes
rapid movements /automatic responses that do not involve the conscious part of the brain.
what is a reflex arc?
a reflection arc is a nerve pathway which allows a passage of information to be passed from the receptor to the effector in such a short time.
describe in detail what your body does to respond to a hot pan burning your hand.
- stimulus (hot pan) is detected by receptors.
- impulses are sent along the sensory neurone the relay neutron in the CNS (central nervous system).
- when the impulse reachers a synapse between the sensory neutron and the relay neuron, they trigger chemicals to be released which causes the impulse to be sent along the relay neurone.
- impulses then travel back along the motor neurone to the effector (muscle). the muscle contracts and causes the arm to be moved away from the heat.
what can you do to measure reaction time?
the drop ruler test. (drink caffeine on one of turns to see how it effects the test)
what are hormones and where are they created?
hormones are chemical molecules released directly into the blood. they are produced and secreted in various glands called endocrine glands.
what are the six key glands to know and what do they do?
the PITUITARY GLAND-produces hormones that regulate body conditions
OVARIES- produces oestrogen which is involves the menstrual cycle.
TESTES-produces testosterone which controls puberty and sperm production.
THYROID- produces thyroxine which involves regulating thing like rate of metabolism, heart rate and temp.
ADRENAL GLAND-produces adrenaline which prepares body for ‘fight or flight’ mode
the PANCREAS- produces insulin which is used to regulate the bloods glucose levels.
what are three main differences between hormones and nerves?
HORMONES -slower actions -act for a very long time -act in a more general way NERVES -very fast action -act for a vert short time -act on a very precise area
