B3: Organism-level Systems Flashcards
what is a voluntary action
an action that occurs as a result of you consciencely deciding that you want to do something.
What is a reflex action
involuntary reactions that occur without thinking by missing out the brain as this means the reaction can take place faster,normally 0.2 seconds and happen when you are in danger
The reflex arc pathway
stimulus-receptor-sensory neurone-spinal cord-motor neurone-effector-response
voluntary action pathway
stimulus-receptor-sensory neurone-spinal cord-brain-spinal cord-motor-effector-response
stimulus
change in the environment
receptors
group of cells that detect the change in environment
effectors
where the response occurs from and can be muscles or glands.Muscles respond by contracting and glands responf by relseasing hormones
what do receptor cells do
change the stimulus into electrical impulses that travel along neurones to your CNS
What is the CNS
-central nervous system
-made up of the brain and spinal cord
-very delciate so are protectd by bones.Skull protects brain,backbone protects spinal cord
light’s receptor cell and sense organ
r-light
so-light
chemical’s receptor cell and sense organ
r-taste
so-tounge
pressure and heat’s receptor cell and sense organ
rc-pressure and temperature
so-skin
chemical’s receptor cell and sense organ
r-smell taste
so-nose
sensory neurone
carries electrical impulses from receptor cells to the CNS
relay neurones (reflex arc only)
-carry electrical impulse from sensory neurone to motor neurone across the spinal cord
motor neurones
carry electrical impulses from the CNS to effectors
nerves
the term to describe the bundles of the the hundreds or even thousands of neurones found together
cornea
transparent coating on the front of the eye that protects the it and also refracts incoming light
pupil
the central hole in the iris that allows light to enter the eye
iris
coloured ring of muscle tissue that altars the size of the pupil by contracting or relaxing
lens
transparent bioconvex lens that focuses light clearly onto the retina
ciliary body
ring of muscle tissue that altars the shape of the lens
suspensory ligaments
ligament tissue that connects the ciliary muscle to the lens
optic nerve
nervous tissue that carries nerve impulses to the brain.