Homeostasis and Response Flashcards
(59 cards)
why is homeostasis important
cells need the right conditions to function properly, also for enzyme action
what is homeostasis
regulation of conditions inside the body to maintain a stable environment in response to changes
give examples of control systems
temperature, water content, blood glucose
give the components that work together in homeostasis
effectors, receptors and coordination centres
what is negative feedback
bringing the level of something back to normal
what is a stimulus
change in environment
what is the process for when something is too high/low
- receptor detects stimulus is too high/low
- coordination centre processes information and organises a response
- effector produces a response that counteracts the change
what does the nervous system mean
humans can react and coordinate behaviour
what is the difference between prokaryote nervous systems and eukaryote nervous systems
prokaryotes have reflexes and eukaryotes have nervous systems
what is the CNS
brain, spinal chord, sensory and motor neurones
what are sensory neurones
carry info as electrical impulses from receptors to CNS
what are motor neurones
carry info as electrical impulses from CNS to effectors
what are effectors
all muscles and glands that respond to nervous impulses
what is a synapse
connection between two neurones
how does a neurone transfer to another neurone
nerve signal transferred by chemicals diffuse across gap sets off electrical signal in next neurone
what are reflexes?
rapid, automatic responses to certain stimuli that don’t involve the conscious part of the brain - they can reduce the chance of being injured
what is an example of a reflex?
if a bright light is in your eye, your pupils get smaller so that less light gets in the eye to stop it getting damaged.
what are the 6 steps to a reflex arc?
- stimulation of pain receptors
- impulses travel along sensory neurone
- impulse pass along relay neurone through a synapse
- impulse travels along a motor neurone via synapse
- impulse reaches muscle and muscle contracts
how do you do the ruler drop test in 6 steps?
- person rests their arm on the edge of a table
- hold a ruler above their hand and let go without any warning
- person should try to catch the ruler to measure reaction time
- write down the measurement of them catching it
- repeat the test several times and calculate the mean
- repeat but give the person caffeine
what are hormones 5
- chemical molecules released into the blood
- only affect target organs
- long lasting effects
- control things that need constant adjustment
- controlled and secreted endocrine glands that make up your endocrine system
what is the pituitary gland?
- in your brain, looks like an egg
- regulate body conditions
- master gland
what is the thyroid?
- in your throat, looks like a butterfly
- produces thyroxine
- regulates metabolism, heart rate and temperature
what is the adrenal gland?
- looks like a cupcake, in your stomach
- produces adrenaline
- fight or flight
what is the pancreas?
- in your stomach, looks like a rat
- produces insulin
- regulates blood glucose
