nervous system Flashcards
(12 cards)
what is the nervous system made up off?
brain
spinal cord
nerves
how is the nervous system divided?
central nervous system
peripheral nervous system
decribe the central nervous system…
-controll centre of the nervous system
-includes brain +spinal cord
-receives info from sensory cells,interprets them, sends out signal to cause response
-signals can be conscious or unconscious
describe the peripheral nervous system…
-consists of nerves outside the CNS, connecting limbs and organs to the brain and spinal cord
-messenger system
-somatic nervous system=voluntary body functions
-autonomic nervous system=controls involuntary body functions
what does the somatic nervous system (SNS) do?
coorinates voluntary movement responding to the external enviroment via skeletal muscles.also recieves information from sensory receptors
what does the autonic nervous system do (ANS)?
contols body involuntary process,responding to internal enviroment . Ensures essential boilogical processes continue. Can be divided into sympathetic nervous system and parasympathetic nervous system
describe the Sympathetic system (part of the ANS)?
-used if body is in danger
-sends adrenaline and
-makes changes needed for fight or flight response
describe the parasympathetic system (part of ANS)?
acts in opposite way to SNS
e.g if SNS increases heart rate tihs would decrease it
describe the motor neurons …
-motor neurons =specilaised nerves responsible for muscle movement
describe moter units…
-can contain between 10-thousands of muscle fibres
-larger numbers will create powerful movements
-fewer fibres will provide smaller more accurate movement
what is the all or none principle?
muscles fibres will either all contract or none at all
the strength of impulses dictates whether or not fibres contract. impulses must reach a certain threshold level before muscle fibres contract
what does neuromuscular refer to?
the connection between the motor neurons and the muscles they suply
