the nervous system Flashcards
what is the central nervous system made of
brain and spinal cord
function of receptors
detects the stimulus by changing it’s energy into electrical energy
what is an effector
a structure that responds to nerve impulses, may be a muscle or a gland
types of nerve cells
sensory neurone
motor neurone
relay neurone
features of sensory neurone
1.transmits nerve impulses from receptor to central nervous system
2.cell body located outside CNS
3.has a long dendron
4.has a short axon
features of motor neurone
1.transmits nerve impulses from central nervous system to muscles and glands
2.cell body is located inside the CNS
3.cell body has dendrites which are junctions with other neurons
4.has long axon to carry nerve impulses to effector organ
5.the axon is covered by myelin sheath which insulates the axon and speeds up the conduction of impulses
6.the impulse is transmitted from the axon to the muscle through a synapse called nerve muscle junction
function of relay neurone
transmits nerve impulse from sensory neuron to motor neurone
what is a synapse
a gap between two neurons across which a nerve impulse can pass by chemicals known as neurotransmitters
structure of spinal cord
the middle part is called the grey matter
the outside part is called the white matter
mechanism of transmission of nerve impulse across the synapse
1.impulses arrive down the axon of one neuron
2.the impulse stimulates the release of neurotransmitters
3.neurotransmitters diffuse across the synaptic gap
4.neurotransmitters attach to receptors on the membrane of the second neuron generating another electrical impulse
what is a reflex action
automatic, involuntary, rapid response to a stimulus, which often protects the body
reflex arc of withdrawal of a finger from a hot object
1.receptor responds to a stimulus and sends nerve impulses to sensory neurone
2.sensory neurone transmits nerve impulse from receptor to CNS
3.relay neurone transmits nerve impulse from sensory neurone to motor neurone
4.motor neurone transmits nerve impulse from CNS to effector
5.effector responds to nerve impulse and contracts and pulls hand away
features of the reflex arc
1.involuntary
2.fast response
what is the cerebrum
largest part of the brain which is made of two cerebral hemispheres
3 functions of the cerebrum
1.has sensory areas that receive and process information from our sensory organs
2.it has motor areas where all voluntary actions originate
3.it is the origin of all higher activities, such as memory, emotions and personality
where is the cerebellum
behind the cerebrum
function of cerebellum
coordinating muscle contraction
maintaining balance
where is the medulla
underneath the cerebrum
function of medulla
1.connects the spinal cord with the brain
2.controls basic body activities, such as heart beat and breathing rate
where is the pituitary gland
located at the base of the brain just below the hypothalamus
function of pituitary gland
secretes hormones into the blood
function of hypothalamus
1.coordinates between nervous and endocrine system
2.responsible for many homeostatic processes
causes of alzheimer’s disease
build up of two proteins in brain cells called amyloid and tau, which damage and kill brain cells
symptoms of alzheimer’s
forgetting recent events, names, and faces
becoming increasingly repetitive
getting lost
becoming anxious
problems with speech
treatment of alzheimer’s
1.in early stages, they take drugs that increase the amount of neurotransmitters
2.non drug treatment can be used(activities that stimulate thinking skills)
causes of vascular dementia
diseased or damaged blood vessels in the brain which decrease the supply of oxygen and nutrients to the brain cells so the cells die
symptoms of vascular dementia
problems with memory and thinking
treatment of vascular dementia
drugs are used to lower the blood cholesterol to lower the risk of strokes
causes of parkinson’s disease
1.death of certain neurons in the brain which produce the neurotransmitters dopamine
2.decrease of dopamine levels causes abnormal brain activity
symptoms of parkinson’s disease
1.difficulty in walking
2.posture becomes bent over
3.difficulty in speaking clearly
4.loss of automatic movement
treatment of parkinson’s disease
Livodopa
causes of schizophrenia
1.high levels of dopamine
2.stress
3.drug abuse
symptoms of schizophrenia
1.lack of interest in things
2.becoming anxious
3.hallucinations
4.difficulty in concentrating
treatment of schizophrenia
1.antipsychotic drugs
2.family intervention therapy
causes of depression
1.mental health problems
2.poor physical health
3.bad childhood experience
4.life changing events
5.drugs or alcohol abuse
symptoms of depression
1.feeling sad or upset
2.unable to relate to other people
3.no self esteem
4.suicidal thoughts
treatment of depression
1.antidepressant drugs
2.taking therapy
examples of illegal drugs
heroin
cannabis
cocaine
dangers of heroine
1.addiction
2.overdose can lead to death
3.withdrawal symptoms
4.criminal behavior
dangers of cannabis
1.hallucinations
2.user becomes confused
3.anxious
4.depression
dangers of cocaine
1.highly addictive
2.increase heart rate and blood pressure to a dangerous high level
3.nose bleeding
4.tremors
5.seizures
6.dizzines
what is alcohol
a brain depressant, slows down nervous system
dangers of alcohol
1.delayed response to a stimulus
2.large amounts interfere with balance and muscular control
3.blurred vision
4.high conc. can lead to coma and death
alcohol addiction
causes brain damage, damage to the lining of the stomach, and liver cirrhosis
what is paracetamol
a painkiller that inhibits an enzyme controlling the production of chemicals in the body called prostaglandins which cause pain and fever
what does paracetamol do
reduces fever by affecting the area of the brain regulating the temperature
function of cornea
bends lights
function of lens
bends and focuses the light into the retina
function of iris
changes the size of the pupil and control the amount of light entering the eye
function of choroid
contains dark pigments to prevent reflection of light rays inside the eye
function of retina
has light receptors(rods and cones)
function of fovea
point of clearest vision(has most vision)
function of blind spot
point of no vision on retina(has no rods or cones)
function of optic nerve
transmits nerve impulse from retina to the brain
function of ciliary muscle and suspensory ligament
changes the shape of the lens in accommodation
pupil reflex in bright light
circular muscles of iris contract
radial muscle of iris relax
pupil becomes smaller
pupil reflex in dim light
circular muscle of iris relax
radial muscle of iris contract
pupil becomes larger
accommodation to near object
ciliary muscle contracts
suspensory ligaments are loose
lens is fat
accommodation to distant object
ciliary muscle relax
suspensory ligaments are tight
lens is thin
what is binocularvision
to see an object with both eyes at the same time
advantages of binocularvision
3d vision
judging distances
wide field of vision
what is long sight
when the lens is not convex enough or the eyeball is too short, has difficulty focusing on nearby objects
treatment of long sight
using convex lenses or glasses
what is short sight
when the lens is too convex or the eyeball is too long, difficulty focusing on far objects
treatment of short sight
using concave lenses
what is astigmatism
a minor defect in the structure of the eye that causes blurred vision
treatment of regular astigmatism
wearing glasses or contact lenses
treatment of irregular astigmatism
only contact lenses
what is cataract
condition where the lens of the eye becomes cloudy or opaque
treatment of cataract
by surgery
what is corneal transplant
when the cornea is damaged it can be replaced by a cornea from a donor
the ear has 3 parts:
outer, middle, and inner
function of the outer ear
directs sound waves to the ear drum causing it to vibrate
function of the middle ear
amplify the vibrations as they pass through small bones(malleus, incus, and stapes)
function of stapes
transmits the vibrations to the cochlea
function of eustachian tube
connects the middle ear to the throat and allows pressure to equalize on both sides of the ear drum
function of cochlea
has receptor cells that convert the vibrations to nerve impulses
role of ear in hearing
1.ear pinna collects sound waves from air
2.sound waves enter the ear causing the ear drum to vibrate
3.the 3 ossicles amplifies vibrations and transmits it from the ear drum to the cochlea
4.the fluid in the cochlea vibrates stretching receptor cells
5.the receptor cells respond by generating nerve impulses at the neurons
6.impulses are transmitted to the brain via the auditory nerve
role of ear in balance
1.in the swelling at the end of semicircular canals are more hair cells embedded in a jelly like mass called cupula
2.movement of fluid in semicircular canals cause the cupula to pull on hair cells
3.hair cells send nerve impulses to the brain
4.the canals are arranged in right angles to each other to detect movement in any direction
noise induced hearing loss
1.long lasting sounds can damage the sensitive structures within the ear causing hearing loss
2.a very loud noise such as an explosion, can rupture the ear drum
3.exposure to loud noise can cause temporary deafness or buzzing sounds in the ear called tinnitus
what is a hormone
a chemical that is usually protein in nature, secreted by an endocrine gland, transported, and dissolved in plasma, and works on specific target organs
source of adrenaline
adrenal gland
role of adrenaline
prepares body for stress
effect of adrenaline
- increase heart rate, so more blood reaches the muscle, more respiration, and energy release, and remove excess co2 and lactic acid
2.increase breathing rate and dilates bronchioles, so more oxygen reaches the muscles, more respiration, and energy release, and removes excess o2
3.converts glycogen in liver to glucose, so more glucose reaches the muscles, more respiration occurs and energy is released
what happens during negative feedback
a change in the conditions of the body is detected and process starts to return the conditions back to normal
where is insulin released from
pancreas
when is insulin released
when glucose concentration in the blood rises
what does insulin do
stimulates liver to change glucose to glycogen, to lower blood glucose level
what does glucagon do
glucagon stimulates the liver to break down glycogen into glucose, to raise blood glucose level
when is glucagon released
when glucose level is low
differences between nervous and hormonal communication
in nervous, message sent in electrical nerve impulse
in hormonal message sent in chemical substance
in nervous, there is a rapid response
in hormonal, slow response
in nervous, gives a short lived response
in hormonal, gives a long term response
