Coordination and control Flashcards
stimulus
is a change in the external and internal environment
response
is a change in an organisms or part of one which is brought about by a stimulus
receptor cells
part of a organism that detects stimulus
effector cell
part that responds to the stimulus
nervous system
messages are carried as electrical impulses at rapid rates to precise areas of the body and they have an immediate but short lasting effect. This is made up of the CNS and PNS
parts of the brain
cerebrum- controls conscious thoughts and is responsible for memory
cerebellum - coordinates movement
medulla- coordinates involuntary actions
hypothalamus- assist in the release of hormones such as ADH and FSH
pituitary gland - secrets hormones
neurones
specialised cells that conduct nerve impulses throughout the nervous system
receptor cell - sensory neurone - relay neurone - motor neurone - effector cells
synapse
the space between 2 neurones , where the impulses leave 1 neurone and turn into a chemical known as neurotransmitters and enters into the 2nd neurone . this is to ensure that the impulses travel in 1 direction
voluntary actions
something done - by your decision
relay - motor - skeletal muscle eg. talking
these are complex and can be learnt
involuntary actions
not learned and simple
eg , blinking
autonomic nervous system - motor nerves eg. breathing rate
reflex actions- external stimulus , requires a reflex arc
reflex- cranial reflex and spinal reflex
sense organs
eyes - photoreceptor
ears - mechanoreceptor
nose - olfactory cells
tongue -chemoreceptors
skin- receptor cells
image formation
the cornea and lens refracts the light rays unto the retina. An image of the object is formed which stimulates the light sensitive cells and reverse and inverts the image. The optic nerve carries impulses to the brain and the brain flips the image the correct way and forms and impression of size , colour and distance of object
rods
low light intensity and detects black and white
cones
high light intensity and detects colours green, red and blue
shortsighted
causes - the eye ball is too long and light rays fall at the front of the eye
corrected - with diverging lens
longsighted
causes- the eye ball is to short and light rays fall at the back of the eye
corrected- with converging lens
old sight
difficult to see near objects , caused when lens elasticity reduces and ciliary muscles weaken
corrected by converging lens
astigmatism
when the lens and cornea is unevenly curved , both near and distant objects are blurry
corrected by wearing unevenly curved lens that counteract the uneven curvature
glaucoma
when fluid in the eye pressure increase due to the flow of the aqueous humour being blocked . can lead to blindness
treated with drops or surgery
cataracts
cloudy area forms in lens and is corrected by surgery and replace with artificial lens
endocrine system
carries hormones in blood very slowly and are carried to a generalised area and has a long lasting effect
gland , their location and functions
pituitary gland - in the brain attached to the hypothalamus and secrets ADH , GH , FSH AND LH
thyroid gland - front of the neck, secretes thyroxine which controls metabolism
adrenal gland- above kidney , secrets adrenaline the flight, fight or fright hormone
pancreas - in the duodenum secrets insulin
ovaries - end of fallopian tubes in women secretes oestrogen and progesterone
testes- in the scrotum sac, secretes testosterone
