nervous system and eye Flashcards
what are the conditions inside your body known as
internal environment
what is homeostasis
homeostasis is the regulation of the conditions inside your body to maintain a stable internal environment in response to internal or external changes
why does your body regulate the internal conditions in your cells
your body regulates the internal conditions in your cells to maintain an optimum temperature for your cells to work properly in response to changes externally or internally
why is it important for your body to respond to changes from the internal or external environment
so your body can maintain an optimum temperature for your cellular enzymes
what conditions are kept controlled in your body
body temperature
water content
blood glucose levels
what does your body use to detect and respond
automatic control system (nervous system)
what does your receptors do
They detect changes from the internal or external environment
what are the changes to your internal and external environment known as
stimuli
what does your coordination centre do and example of it
Your coordination centre receive and process information from your receptors and then sends out signal and coordinates these responses of the body
examples brain and spinal cord
what does your effectors do
these carry out the responses of the stimulus and restore the condition of your body back to its optimum temperature
what sub cellular cells do receptors have and where are they found
receptors have a nucleus, cell membrane and cytoplasm
they are found in clusters in sensory organs e.g eyes
how does your nervous system works
1) your receptors detect a change of stimulus then sends out signals along the sensory neuron to the CNS (central nervous system)
2) your CNS then coordinates the responses of the instruction and sends out signals along your motor neuron to effector organs
3) your effector organs then carry out these responses restoring back the conditions of your body
what are neurons
neurons are clusters of nerves
what is the independent (I) dependent (D) and control (V) variable of the reaction time experiment REQUIRED PRACTICAL
I- person having their reaction time tested
D- reaction time
C - starting distance between ruler and finger, conditions of the room and what we measure the ruler to get our recording
steps of reaction time experiment REQUIRED PRACTICAL
1) student 1 sits with a good posture and places their dominant hand over the edge of the table
2) student 2 then places the ruler vertically above students 1 thumb and first finger
3) student 2 then drops the ruler at a random time and student 1 catches it
4) student 2 then records the measurement of the ruler from the level of the thumb
5) the test is repeated several times then a mean is calculated
what are reflexes
automatic responses
what are reflexes used for
- to avoid danger
- help with your basic body functions e.g breathing
- they help do unconscious act which do not require the conscious part of the brain
how are reflexes so fast
- they do not use the conscious part of the brain so the result time between the stimulus and the effector organ is as short as possible
how does your reflex arc work
1) skin receptors detect a stimulus and send electrical impulses along the sensory neuron
2) the sensory neuros then releases chemicals which diffuses along the synapse to the relay neuron ad this starts a new electrical impulse
3) the electrical impulse continues to travel along the relay neuron until it meets another synapse, which then the relay neuron release chemicals which diffuses across the synapse to the motor neuron starting another new electrical impulse
4) the electrical impulse travels along the motor neuron until it reaches the last synapse which it then releases chemical which diffuse across the synapse to the effector
where is the relay neuron found
spinal cord
what are synapses
their gaps between neurons
what are the disadvantages of synapses
- they slow down electrical impulses, delaying the reflex arc
how do synapses work
1) an electrical impulse is sent to the pre synaptic neuron
2) this cause the neuron vesicle to move towards the membrane of the pre synaptic neuron
3) neuron transmitters (chemicals) then diffuse across the synapse and attach onto the receptors of the post synaptic neuron
4) if enough neuron transmitters attaches onto the receptors it generates a new electrical impulse into the post synaptic neuron
5) some neuron transmitters are recycled back to the post synaptic neuron
where is the brain found and what is it surrounded by
- it is found inside a skull and is surrounded by a protective membrane called meninges
what does the cerebral cortex do
- it is the conscious part of the brain and controls memory language and intelligence
what does the cerebellum do
it controls the muscle activity and balance