Coordination and response Flashcards
what is stimuli?
stimuli is the change in an organism’s environment.
which specialized cells detect stimuli?
receptors
what is the role of effectors?
parts of the body that respond to stimuli. ex: muscles and glands
what are the two methods of sending information from receptors to effectors in animals?
nerves(faster method) and hormones(slower method)
what is coordination?
ensures that the actions in the parts of the body work together
how are neurons structure adapted to carrying electrical impulses quickly?
they have long, thin fibers of cytoplasm stretching out.
the axon is insulated by a fatty (myelin) sheath - the fatty sheath increases the speed of the nerve impulses along the neuron
what is the central nervous system(CNS) made up of?
brain and spinal cord ,it is made up of neurons
what is the role of CNS?
coordinates the electrical impulses travelling.
what is the peripheral nervous system(PNS) made up of?
it is made up of nerves spreading out form the CNS,
what are the three neurons used to relay information to an effector?(in order)
sensory neuron, relay neuron, motor neuron
what is the pathway along which nerve impulses pass called?
reflex arc.
what is a synaptic gap?
a tiny gap between 2 neurons
what do the vesicles in the sensory neuron’s axon contain?
contain a chemical called neurotransmitter.
explain how the electrical impulses in a sensory neuron travel through the synaptic gap.
when an electrical impulse arrives at the axon of the sensory neuron, it causes the vesicle to move to the cell membrane of the sensory neuron, they FUSE with the membrane and empty their contents, the neurotransmitter DIFFUSES through the gap and attach to receptor proteins.
what is the role of retina?
contains receptor cells that respond to light and sends electrical signals to the brain.
where is the fluid that keeps the surface of the eye moist made?
in the tear glands
what is the name of the enzyme present in the fluid which keeps the surface of your eye moist?
lysozyme.
what is the role of the optic nerve and where is it found?
carries electrical impulses from the retina to the brain, found in the back of the eye.
which part of the eye has the receptor cells closely packed together?
Fovea
what are the 2 kinds of receptor cells in the eye?
rods and cones
what is the role of rods, and where are they present?
rods respond to dim light and provide black and white vision, rods are receptor cells present in the retina
what is the role of cones, and where are they present?
cones respond to bright light and provide color vision, found in the retina mostly in the fovea.
which part of the eye is colored?
Iris.
what are the 2 roles of the iris?
absorbs light and stop light passing through and alter the size of the pupil
what happens to the pupil in low light intensity?
the pupil widens so more light can get through the retina
what happens to the pupil in high light intensity?
the pupil closes in, this stops the light from damaging the retina.
what are the muscles present in the iris?
circular and radical muscles.
which muscle makes the pupil of the eye smaller?
circular muscles.
what happens when the radical muscle contracts?
the pupil dilates, or gets larger
what are circular and radical muscles?
antagonistic muscles
define antagonistic muscles.
muscles that work together to control an action but have opposite effects.
what part of the eye refracts the light rays entering the eye?
cornea
how does the light ray refract when an object is in a distance? how does it refract when an object is near?
the object in a distance, they do not need much bending, bends slightly. Light rays from nearby need more bending, they bend inwards strongly.
how is the lens altered to bend light rays more?
the thicker the lens, the more the light ray bends
how is the lens altered to bend the light rays less?
the thinner the lens, the less the light ray bends.
what is accommodation?
changing the shape of the lens to focus on objects at different distance.
which fibers hold the lens in position?
suspensory ligaments
which muscle affects the lens?
ciliary muscle
what happens to the suspensory ligaments when the ciliary muscles contract?
the suspensory ligaments relax and vice versa.
How is the shape of the lens altered when the ciliary muscle contracts?
the lens get thicker.
what happens to the shape of the lens as the suspensory ligaments contract?
the lens are puller thin.
in which gland are hormones made?
endocrine glands.
how are the hormones carried around?
in the blood around the body in the blood plasma.
what are target organs?
organs whose activity is altered by hormones.
where are the adrenal glands located, and what hormone do they excrete?
there are 2 adrenal glands one above each kidney, they make a hormone called adrenaline.
what is the role of the adrenaline hormone? and which organs does it target (name any 2 or all)?
the adrenaline hormone sends impulses to your nerve when you are in a stressful or dangerous situation. It targets your eyes, heart, airways, blood vessels and the adrenal gland.
what affect does adrenaline have on the liver, and what does it help with?
the adrenaline causes the liver to release glucose into the blood, this helps the muscle to increase their metabolic activity.
difference between nervous system and endocrine system (name 4 at least) ?
nervous system:
- made up of neurons
- information transmitted in the form of electrical impulses.
- travels quickly, action is fast.
endocrine system:
- made up of glands
- information transmitter through chemicals
- travels slowly, so action is slower.
what is tropism?
a growth response by a plant.
what are the two important stimuli for plants?
light and gravity.
what is phototropism and gravitropism?
-phototropism is a response in which part of a plant grows towards or away from the light.
-gravitropism is a response in which part of a plant grows towards or away from gravity.
how does the shoot of the plant react to the pull of gravity?
shoots usually grow away from the pull of gravity. they are negatively gravitropic.
they are positively phototropic.
how does the roots of the plant react to light?
the roots of a plant need to grow downwards, hence they are positively gravitropic .
they are negatively phototropic.
what is the name of a plant hormone?
Auxin.
where is Auxin made?
at the tip of a shoot.
what affect does auxin have on a plant?
makes the cells behind the tip get longer.
the more auxin there is, the faster they grow.
what happens to auxin when light shines onto a shoot from all around?
The auxin is distributed evenly, so the shoot grows straight upwards.
how is auxin distributed when light shines on only one side of the shoot?
The auxin concentrates on the shady side, so the shoot grows towards the light.
