Chapter 10 - Nerves Flashcards
What is the role of a receptor?
It detects change in the environment
What is the co-ordination centre’s role?
It receives and processes information and co-ordinates responses
What is the role of the effector?
It is a muscle or gland that brings about a response
What is the stimuli?
A change in the environment
What is homeostasis?
Conditions in the body are controlled to provide a constant internal environment
What is a reflex action?
A bodily response to a stimulus without the involvement of the brain
Example: blinking, if someone click med their fingers in your eye, you might blink without meaning too
What is a conscious action?
An action done on purpose with the use of the brain
Example: Eating, you intend to eat when you do
What is an electrical impulse?
An electrical signal that travels along the axon
What is the usual order of a reflex arc?
Receptor Sensory neurone Central nervous system Relay neurone Motor neurone Effector
What is a sensory neurone?
It carries signals from receptors to the Central nervous system
What is the role of the relay neurone?
connects the sensory neurone and the motor neurone
What is the role of the motor neurones?
They carry signals from the central nervous system to effectors
what is the central nervous system
The part of the nervous system made up of the brain and spinal cord
what is a synapse
A tiny gap between two nerve cells, which nerve signals must cross
how is an impulse transferred over a synapse
chemicals are released and diffuse over the gap, these chemicals then set off a new electrical signal in the next neurone
what carries out a response
effectors
what connects neurones
synapse
what are reflexes
automatic responses to certain stimuli without the conscious part of the brain
what is the point of reflexes
they reduce chances of getting injured
if someone shines a bright light into your eye, what reflex happens
your pupils automatically get smaller to allow less light in to stop it getting damaged
what is a reflex arc
passage of information in a reflex (receptor to effector)
what part of the CNS do reflex arcs usually go through
unconscious part of the brain or the spinal cord
what reflex happens if you get shocked
your body releases the hormone adrenaline automatically
What is the cerebral cortex
its responsible for consciousness, intelligence, memory and language
What is the cerebellum
controls muscle co-ordination
What is the medulla
controls unconscious activity such as breathing and heart beat
what is the hypothalamus
controls blood temperature
what is another name for the thermoregulatory centre
hypothalamus
what disease causes muscle tremors
Parkinson’s disease
what is a muscle tremor
involuntary movement of a body part
What is the sclera
the tough, supporting wall of the eye
what is the cornea
transparent layer found in front of the eye, it refracts light into the eye
what is the iris
contains muscles that allow it to control the diameter of the pupil and therefore how much light enters the eye
what is the lens
it focuses the light onto the retina
what receptor cells are contained in the retina
light intensity sensitive cells and colour sensitive cells
what controls the shape of the lens
ciliary muscles and suspensory ligaments
what is the optic nerve
carries impulses from the receptors on the retina to the brain
what is accommodation
the changing of the lens shape to help focus light on the retina
what happens to the ciliary muscles as you look at near objects
they contract
what happens to the suspensory ligaments as you look at near objects
they relax
what happens to the ciliary muscles as you look at distant objects
they relax
what happens to the suspensory ligaments as you look at distant objects
they contract
what happens to lens as you look at near object
it becomes fatter (more curved) which refracts light by a larger amount
what happens to lens as you look at distant object
it becomes thinner (less curved) so it refracts light by a smaller amount
what happens to your lens as you grow older
they loose flexibility so viewing near objects is harder as they cant focus (thus they have reading glasses)
what happens if the eye cant refract light by the right amount
the person is either short or long sighted
what is hyperopia
the medical term for long sightedness
what is the medical term for long sightedness
hyperopia
what type of lens would a long sighted person need
convex
what are convex lens
lens that curve outwards (used by long sighted people)
what is myopia
the medical term for short sightedness
what is the medical term for short sightedness
myopia
what type of lens would a short sighted person need
concave lens
what are concave lens
lens that curve inwards (used by short sighted people)
What are contact lenses
they are thin lenses that sit on the surface of your eye
what are the pros of contact lenses
they are lightweight and almost invisible and you can wear them for sports
what are the cons of contact lenses
they carry a high risk of infection
what 2 type of contact lenses are there
hard lenses and soft lenses
what is laser eye surgery
it is used to change the shape of the cornea affecting the level of refraction of light into the eye
what are the pros of laser eye surgery
surgeons can precisely laser the eye which completely corrects vision
what are the cons of laser eye surgery
risk of complications, possible reaction against the surgery making vision worse than before
what is replacement lens surgery
the lens is removed and replaced with an artificial lens
what are the pros of replacement lens surgery
you receive a new and improved lens
what are the cons of replacement lens surgery
possible damage to retina, higher risks than laser eye surgery
what makes up the CNS
spinal cord, brain
what is the only neurone found inside the CNS
relay neurone
what type of impulse travels along neurones
electrical
what method is used by chemical transmitters to move between neurones
diffusion
what is a chemical transmitter
a chemical released at a synapse to help transmit electrical impulses move between neurones
name different reflexes
heart beat, breathing, blinking, sneezing, coughing
what is the medulla
controls automatic functions
