B10 The Human Nervous System Flashcards
What is homeostasis?
The act of your body controlling it’s internal factors when the external factors. So that there is a stable enviroment so that your body can work at the optimum levels
eg PH levels require a certian tempreture to work best.
What might homeostasis effect
Tempreture
Blood glucose levels
Water content
What are the main parts of your controll systems?
Recepters, Co-ordinating centers and Effecters
What is negative feedback?
The automatic prosses of which your body regulates itself
Your recepters detect a stimulus (blood glucose is too high)
The co-ordinating center recieves the info and organises a responce
Effectors produce the responce and restores it to the optimum level by lowering it.
…
Then the recepters detect that the blood glucose level is too low and repetes the steps…
What is the nervus system made up of?
CNS - Central Nervus system - The spinal cord and brain
Sensory neurons - The neurons that carry info as electrical impulses from the recepters tp the CNS
Motor neurons - The neurons that carry info as electrical impulses to the effectors
Effectors - all your muscles and glands which can respond to nervus impulses
What are recepters?
What is a stimulus
Things that detect change
Taste, smell, sight, sound …
A stimulus is any change in your surroundings
What happens when you see a red light whilst driving?”
Your eyes (recepters) detect the stimulus.
Sensory neurons would send a electrical impulse to the CNS.
The message will travel up your spinal cord to get to the brain
Your brain co-ordinates a responce
Motor neurons are sent to tell the effectors to react.
The effectors react. Muscles contract and you press down on the breaks
What are the 3 types of neurons?
Recepter neurons
Interneurons - relay neurons
Motor neurons
What are reflex reactions?
Something which you do withought thinking about. (A automatic responce)
They normally stop harm
Eg - eyelids close when you try and touch tour eyes. Keeping your balnce. Closing your eyes when you sneeze
What happens when you step on a nail?
Recepters fell the stimulus of pain on your foot and sends sensory neurons to your CNS
The sensory neurons get to the spinal cord and sends 2 electrical impulse messages. 1 to the brain and 1 through relay neurons in the spinal cord.
The relay neurons then reach the motor neurons which send an electrical impulse which travels to the muscles in your foot.
Your muscle then contract
THE BRAIN IS NOT INVOLVED IN A REFLEX REACTION.
What is a synapse
A synapse is the gap of where 2 neurons meet. The electrical impulses can’t pass this gap.
What happens when a neuron reaches a synapse?
The neuron reaches the end of the neuropathway.
It will then relases chemicals which diffuse across the gap. These chemicals then form another electrical signal in the next neuron
