Co-ordination and Control Flashcards
what does coordinated mean?
that the body is able to make things happen in different parts of the body at the right time
what two systems do humans and other animals have which make a coordinated response?
- the nervous system
- the endocrine (hormone) system
how can plants respond to changed in their environment?
- for example they can respond to the direction of light and grow towards it- this is called phototropism and will be covered in greater detail later
what three things does a coordinated response require?
- a stimulus
- a receptor
- an effector
what is a stimulus?
- change in the animal’s surroundings
- e.g. a ball is thrown towards you
what is a receptor?
- is the organ which detects the change
what is the effector?
- muscles are the effectors and they contract as you catch the ball
how is the link between the stimulus and response made?
- by the nervous or endocrine system
what do receptors do?
- detect the stimulus and change its energy into nerve impulses
ex. of a receptor
- sense organs - the eye converts light energy into nerve impulses
what energy conversion does the eye receptor do?
- light to nerve impulses
what energy conversion does the ear receptor do?
- sound to nerve impulses
what energy conversion does the tongue receptor do?
- chemical to nerve impulses
what energy conversion does the nose receptor do?
- chemical into nerve impulses
what energy conversion does the skin receptor do?
- pressure into nerve impulses
what energy conversion does the skin (touch receptor) receptor do?
- pressure into nerve impulses
what energy conversion does skin (temperature receptors) do?
- heat into nerve impulses
what are the parts of the nervous system?
- central nervous system
- peripheral nervous system
central nervous system
- consists of the brain and the spinal chord
- the CNS coordinated all of the nervous responses such as moving or reflexes
peripheral nervous system
- contains all of the other nerves which sends impulses to all of the effectors
what are nerve cells called?
- neurones
what are the three types of neurones?
- sensory neurones
- relay neurones
- motor neurones
how do impulses from receptors pass along?
- along sensory neurones until they reach the brain and spinal chord (CNS)
- impulse pass to relay neurones in the CNS
- the impulse is then passed to effectors (muscles or glands) along motor neurones
list the motor neurone structure.
- nucleus
- dendrite
- cell body
- axon
- mylein sheath
function of nucleus
- contains all the genetic information of the cell
function of the dendrite
- tree like projections which connect to different neurones
- one neurone can connect to many other neurones
function of the cell body
- the main section of the cell
- contains the nucleus
functions of the axon
- the long section- electrical impulses travel long distances through the axon
function of the mylein sheath
- insulated the axon and speeds up the transmission of the impulse
what are reflexes?
- automated actions which do not involve the brain
- they are very fast actions which involve the three neurones ; sensory, relay and motor neurones
what is a reflex arc?
- the movement of the impulse from the receptor to the effector
describe the steps involved in the reflex arc.
- the receptors detect the stimulus (change in temp) and send an impulse along the rensory neurone
- the sensory neurone passes the impulse to the spinal cord to a relay neurone. the gap between neurones is called a synapse. the relay neurone then passes the impulse through the spinal cord to a motor neurone.
- the motor neurone causes the effector (in this case arm muscle) to contract and move the arm away from the stimulus (fire)
what is a synapse?
- a small gap between where two neurones meet
- the signal needs to cross this gap to continue on its journey to, or from, the CNS
neurotransmitters
- an electrical impulse travels along an axon
- this triggers the nerve-ending of a neuron to release chemical messengers called neurotransmitters
- these chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the next neurone
- the receptor molecules on the second neurone bind only to the specific chemicals released from the first neurone. this stimulates the second neurone to transmit the electrical impulse
what is the eye?
- a sensory organ which detects light and sends an impulse to the brain which converts that information into an image which is what you ‘see’
cornea
- a curved transparent disc at the front of the eye
- does most of the focusing
pupil
- a circular opening whose size is controlled by the iris (the coloured part of the eye)
iris
- a ring of muscles with a hole in the middle (pupil)
- the iris controls how much light enters the eye
lens
- soft, flexible and transparent
- its shape can be changed to fine tune the focusing of light onto the retina
ciliary muscles
- a ring of muscle at the edge of the eye which circles the lens
- when it contracts the lens gets fatter
- when it relaxes the lens gets thinner
suspensory ligament
- strong fibres which attach the lens to the ciliary muscle
retina
- contains light sensitive cells called rods and cones
optic nerve
- consists of many neurones which carry impulses from the retina to the brain
fovea
- the region of the retina with the greatest number of cones
conjunctiva
- a mucous membrane that covers the eye to prevent infection
iris reflex in dim light
- the radial muscles contract and the circular muscles relax
- this makes the iris narrower and the pupil dilates
iris reflex in bright light
- the circular muscles contract and the radial muscles relax
- makes the iris wider and the pupil constricts
accommodation
- the changes that take place in the eye which allow us to see objects at different distances
light rays when entering the eye at focusing at a far away object
- light rays entering eye are almost parallel when they reach the cornea so the lens does not need to refract them much to focus light onto the retina
