The Nervous System Flashcards
what is the central nervous system made up of
- neurones, also called nerve cells
- which go to all parts of the body
what are sensory receptors
- groups of cells that can detect a change in your environment
- called a stimulus
what is an example of different detectors detecting different stimuli
- receptors in your eye detect light
- while detectors in your skin detect pressure and temperature change
what happens when a stimulus is detected by recpetors
- the information is converted into an electrical pulse (nervous pulse)
- and sent along sensory neurones to the central nervous system
where does the central nervous system run through
the spinal cord and the brain
what happens after the electrical impulses from the receptors have reached the CNS
- the central nervous system coordinates a response
- in other words, it decides what to do about the stimuli and tells something to do it
- impulses travel through the CNS along relay neruones
what does the CNS send information back to and what does that then do
- to an effector along the motor neurone
- an effector could be muscles or glands
- the effector then responds accordingly like a muslces contracting or a gland secreting a hormone
what is the reaction time in relation to the nervous system
the time it takes for you to respond to a stimuli
what do all neurones have
- a cell body with a nucleus
- along with cytoplasm and other subcellular structures
how do individual neurones link of they are cell body with a nucleus
- the cell body has extensions that connect to other neurones
- dendrites and dendrons carry nerve impulses towards the cell body
- and axons carry nerve impulses away from the cell body
what are some axons surrounded by and what does it act as
- they are surrounded by a myelin sheath
- it acts as an electrical insulator which speeds up the electrical impulse
what is the effect of neurones being very long and why
- it speeds up the electrical impulse
- connecting with other neruones slows the impulse down
- so one long neurone is much quicker than lots of short ones joined together
what are the three different types of neurones in the body
- sensory neurones
- relay neruones
- motor neruones
what is the structure and function of a sensory neurone
- one long dendron carries impulses from the receptor cells to the cell body
- which is located in the middle of the neurone
- one short axon carries the nerve impulses from the cell body to the central nervous system
what is the structure and function of a motor neurone
- many short dendrites carry impulses from the CNS to the cell body
- one long axon carries the nerve impulses from the cell body to the effector cells
what is the structure and function of a relay neurone
- many short dendrites carry nerve impulses from sensory neurones to the cell body
- an axon carries nerve impulses from the cell body to the motor neurones
