The Nervous System Flashcards
what is the basic route a reflex takes through the nervous system?
stimulus —> receptor (sense organs) —> coordination (nervous system) —> effector (muscles/glands) —> response
if the stimulus is light what is the receptor?
eye
if the stimulous is sound or balance, what is the receptor?
ear
if the stimulus is smell, what is the receptor?
nose
if the stimulus is taste, what is the receptor?
tongue
if the stimulus is touch, pain, temperature or pressure, what is the receptor?
skin
what are the sense organs (receptors)
eyes
ears
nears
tongue
skin
what is in the central nervous system?
brain
spinal cord
(optic nerve)
what is in the peripheral nervous system?
nerves outside the CNS
what are the effectors?
muscle
glands
effector
an organ (muscle or gland) that brings about a response
nervous system
the vast network of nerves in the body
receptor cell
a cell that senses a stimulus and transmits the message along
stimulus
a detectable change in the environment
response
a change brought about following a stimulus
central nervous system (CNS)
the part of the nervous system that includes the brain, optic nerves and spinal cord
sense organ
a specialised organ with clusters of receptor cells that sense a change in the environment
brain
the control centre of the CNS
spinal cord
a bundle of nerves enclosed in the spine that connects neraly all parts of the body to the brain
reflex
involuntary and almost immediate response to a stimulus
neurone
(nerve cells)
specialised cells which transmits information through nerve impulses
nerve
(nerve cell = a single neuron)
a bundle of several neurones
nerve impulses
electrical sugnal (current) that travels along a neurone
where is the motor neurone
in the peripheral nervous system
where is the sensory neurone
in the peripheral nervous system
where is the relay neurone
in the central nervous system
label this motor neurone diagram
label this sensory neurone diagram
label this relay neurone diagram
which neurone is this
sensory neurone
which neurone is this
relay neurone
which neurone is this
motor neurone
cell body
the oart of the neurone which contains the nucleus
dentrites
extensiones at which nerve impulses are recieved from other cells at synapses and transmitted to the cell body
axon
extension which carried nerve impulses to other neurone or effector organ (muscle or gland)
myelin sheath
faty sheath which insulates the axon (preventing short-circuits of electrical impulses) and speeds up the conduction of nerve impulses; made of Shwann cells
reflex arc
the pathway through the nervous system that a reflex takes
what is the order of the reflex arc
stimulus —> receptor —> sensory neurone —> relay neurone (CNS) —> motor neurone —> effector —> response
sensory neurone, relay neurone, motor neurone = coordination
label this reflex arc diagram
label this spinal cord diagram
what is the spinal cord made up of
long, thin, tubular bundle of nerves
what is the spinal cord enclosed by
vetebral column
the spinal cord is an extension of …. from the ….
the spinal cord is an extension of the central nervous system (CNS) from the **brain **
how quickly does the transmitting of the nerve impulses happen?
can happn in 1/30 of a second
reflexes are … responses, i.e. you don’t need to … about them
generally, the brain is not … in coordinating a reflex
exception: the brain is actively … where the … is located in the … rather than the spinal cord (e.g. …)
the brain is … about a stimulus/reflec happening (e.g. … reflex after touching a hot plate, the brain is informed about the … this causes)
the brain can decide to … a reflex (e.g. you can prevent a … reflex when touching a hot plate, if you don’t want to … it)
reflexes are unconscious/involuntary responses, i.e. you don’t need to think about them
generally, the brain is not involved in coordinating a reflex
exception: the brain is actively involved where the relay neurone is located in the **brain rather than the spinal cord (e.g. pupil reflex**)
the brain is informed about a stimulus/reflec happening (e.g. withdrawl reflex after touching a hot plate, the brain is informed about the painthis causes)
the brain can decide to override a reflex (e.g. you can prevent a withdrawl reflex when touching a hot plate, if you don’t want to **drop **it)
do you have beter or worse balance when your eyes are open?
better
when your centre of balance is titled do your muscle reflexes act slower or faster
faster
name two mai parts of the central nervous system
spinal cord
brain
describe how information from receptors in the nervous system is passed to the CNS
the receptors in the sense organs transmit a signal to the muscle via nerve impulses through the sensory neurone to the relay neurone in the central nervous sysetm
which organ controls the nervous system?
the brain
what are some examples of a reflex action
snatching your hand form a hot object
knee-knock
blinking
coughing
label this reflex arc diagram
give three receptors which a mouse might use to detect food under natural conditions
see the food with eyeys
touch with mouse paws
smell with nose
describe how a mouse respons to a dropped pen
the mouse hears the pen drop (stimulus)
the dendrites in the sensory neurones in the peripheral nervous system are activated by the receptor cells and transmit a signal through the dendron and axon (along with myelin sheath)
this nerve impulse gets transmitted ino the central nervous sysem and intor the relay neurones and through the motor neurone
this activated the mouse’s muscles which moves and the repsonse is to run away
this is called the reflex arc which is the pathway through the nervous system that a reflex takes
it takes 1/30 of a second
synapses
tiny gap between two neurons across which impulses pass by diffusion of a neurotransmitter
neurotransmitter
chmical that passes on a sinal from one neurone to another across a synapse
give examples of a neurotransmitter
amino acids
dopamine
adrenaline
label this diagram of a nerve impulse through a synapse
what is step 1 of transmission of a nerve impulse across a synapse?
the nerve impulse travels along the axon to the synapse in form of an electrical signal
what is step 2 of transmission of a nerve impulse across a synapse?
the vesicles containing neurotransmitter move to the membrane
what is step 3 of transmission of a nerve impulse across a synapse?
the neurotransmitter is emptied into the space between neurone (synapse)
what is step 4 of transmission of a nerve impulse across a synapse?
the neurotransmitter diffuses across the synapses (from high to low concentration)
what is step 5 of transmission of a nerve impulse across a synapse?
the nuerotransmitter binds to the receptors on the surface of the dendrite
what is step 6 of transmission of a nerve impulse across a synapse?
binding of the neurotransmitter triggers a new nerve impulse
what is step 7 of transmission of a nerve impulse across a synapse?
the nerve impulse travels from the dendrite to the axon
How is a nerve impulse transmitted across a synapse (all the steps together)?
step 1: the nerve impulse travels along the axon to the synapse in form of an electrical signal
step 2: the vesicles containing neurotransmitter move to the membrane
step 3: the neurotransmitter is emptied into the space between neurone (synapse)
step 4: the neurotransmitter diffuses across the synapses (from high to low concentration)
step 5: the neurotransmitter binds to the receptors on the surface of the dendrite
step 6: binding of the neurotransmitter triggers a new nerve impulse
step 7: the nerve impulse travels from the dendrite to the axon
what is a disease or condition linked to a defective neurotransmitter function
Parkinson’s
label this eye
label this structure of the eye
conjunctiva
= layer covering the cornea and sclera
helps to lubricate the eye
cornea
= clear covering of eye
helps to refract amd focus on light
lens
= transparent structure behind pupil
refracts and focuses on light
pupils
= hole in centre of iris
controls amount of light entering eye
iris
= pigmented tissue, sphincter
controls amount of light entering eye
suspenory ligaments
= ligaments connecting ciliary muscle and lens
involved in controlling accomodation (focusing)
ciliary muscle
= ring of muscle connected to lens via suspensory ligaments
controls accomodation (focusing)
retina
= inner layer of eye containing rods + cone
responds to light stimulus
optic nerve
= sensory nerve (part of CNS)
carries nerve impulses from retina to brain
in the pupil reflex, which is the:
receptor
sensory nerve
effector
receptor = retina
sensory nerve = optic nerve
effector = muscles in the iris
label this diagram of an eye
what happens to the pupil reflex in dim light
radial muscles contract
circular muscles constrict
pupil dilates
what happens to the pupil reflex in bright light?
radial muscles relax
circular muscles contract
pupil constricts
in the dark a … action occurs: the … gets larger so that more …can enter the eye and you can see
the oppotite happens in bright light: the … gets smaller and this stops too much … entering the eye and … it
the changes in the … are controlled by muscles in the …
when the pupil contracts (in … light), the … muscles contracted and the … muscles are relaxed
when the pupil dilates (in … light), the … muscles are contracted and the … muscles are relaxed
in the dark a reflex action occurs: the pupils gets larger so that more light can enter the eye and you can see
the oppotite happens in bright light: the pupils gets smaller and this stops too much light entering the eye and damaging it
the changes in the pupil are controlled by muscles in the iris
when the pupil contracts (in bright light), the circular muscles contracted and the radial muscles are relaxed
when the pupil dilates (in dim light), the radial muscles are contracted and the circular muscles are relaxed
label this struture of the retina diagram
what are the two photoreceptors?
rods
cones
what are rods sensitive to?
dim light vision
what are cones sensitive to?
colour vision: blue, red, green
what is monochromacy
total colour blindness
what is anomalous trichomacy
red-green blindness
what is night blindness
when rods don’t respond to light
our retinas our covered with light sensitive cells called … and …
the … detect the intensity of light and allows us to see if things are bright or dark
the … detect colour. when there is little light, the … do not work so we find it difficult to tell what … things are
there are … types of cone cells in the retina
each type is sensitive to a different colour of light: …, … or …
our retinas our covered with light sensitive cells called rods and cones
the rods detect the intensity of light and allows us to see if things are bright or dark
the cones detect colour. when there is little light, the cones do not work so we find it difficult to tell what … things are
there are three types of cone cells in the retina
each type is sensitive to a different colour of light: red , blue, or green
accommodation
the reflex that makes the eye focus on an object by changing he shape on its lens
light reflected from an object is … (bent) by the … and the … forming an upside down image on the …
the … interprets this image so that it appears upright to us
the lens … is adjustable and so can bend light more or less, thus allowing the eye to … on an object at different distances
light reflected from an object is refracted (bent) by the cornea and the lens forming an upside down image on the retina
the brain interprets this image so that it appears upright to us
the lens shape is adjustable and so can bend light more or less, thus allowing the eye to focus on an object at different distances
describe how nearby objects appear when focusing on a distant object and why
light rays from a nearby object come into the eye at an angle
if they are not refrcted enough the object will look blurry
describe how distant objects appear when focusing on a distant object and why
light rays from a distant object arrive at the eye nearly parallael
when the eye focuses on a distant object the lens is flatter so that the light rays retract less
describe how nearby objects appear when focusing on a nearby object and why
to focus on a nearby object the lens becomes rounder (more convex) so that light rats are refracted more
describe how distant object appear when focusing ona nearby object and why
the light rays from a distant object are refracted too much so that the object will look blurry
label this mechanism of accommodation diagram for focusing on a nearby object
label this mechanism of accommodation diagram for focusing on a distant object
explain how a reflex arc helps withdrawla finger from a hot plate
a reflex arc is the pathway trhough the nervous sysetm a reflex takes
a detectable change in the environment (stimulus) is sensed by your skin, the receptor (sense organ), and this transmits a nerve impulse through the sesory neurone in the peripheral nervous system
the peripheral nervous system picks up the impulse by its dentrites and transmits the signal along the axon where it is recieved by the dendrites of the relayneurone in the CNS and trasmitted along its axon where it is recieved by the dendrites on the motor neurone in the peripheral nervous system along its axon where an arm muscle (effectro) recieves the impulse which tells us to withdra our finger from the hotplate (response)
the reflex is involuntary and almost immediate so we don’t get burnt
give a reflex to the action that occurs in our in dim light
we can adjust our vision to see in dim light
what is the name of neurone A?
sensory neurone
what is the name of the microscopic gap between B and C?
name X and Y on neurone C
X = nucleus
Y = myelin sheath
which neurone passes impulses from a receptor to the CNS
sensory neurone
B
which neurone is found only in the CNS
a relay neurone
A
