4.2.2 - Neurons Flashcards
What are neurons
Nerve cells
- the body’s communication system, they feature all around the body
What are the 3 types of neuron
- sensory
- motor
- relay
What is the role of sensory neurons
Found in receptors such as ears, eyes, tongue and skin
- they carry here impulses to the spinal chord and the brain
What is the role of a motor neuron
Found in the CNS
- control muscle movements
- when they are stimulated they send signals to the muscles which lead to movement,
What is the role of a relay neuron
Found between input and output/ response neurons
- they are found in the brain and spinal chord
- they allow other types of Enron’s to communicate with each other
What does the CNS consist of
- brain: decides what to do, and tells the body actions
- spinal chord: conveys messages to and from the brain
What are the functions of the nervous system
- controls the body
- takes info from the environment using sensory receptors then sends signals that encode this into the ows.
- the info is processed to work out an appropriate response in the CNS
-output signals are sent to muscles or glands to activate the response.
Where is the cerebellum and what’s its function
- sits at the back of the cerebrum
- controls motor skills
- coordinates muscles to allow precise movement
Where is the brain stem and what is its function
- located at the bottom of the brain and connects brain to rest of body
- regulates essential functions for life
Eg: breathing heartbeat swallowing etc..
Where is the cerebrum and what is its function
- largest part of the brain, and divides into 4 parts which all carry out separate functions
- the two hemispheres are caused by a split down the cerebrum
- each hemisphere communicates using the corpus callosum
What is the somatic nervous system
Transmits info to and from the senses and to and from the CNS to the outside world- carries sensory info to the brain where muscle responses are produced
- sensory receptors: carry info to the spinal chord and the brain
- motor pathways: allows the brain to control movement
What is the peripheral nervous system
Consists of all nerves that are outside of the CNS
- there are throw divisions: the somatic nervous system and the autonomic nervous system
What is the autonomic nervous system
- transmits info to and from the internal organs to sustain life
- plays an important part if homeostasis
- carries out actions without your conscious awareness
- made up of motor pathways:
Sympathetic system - increases bodily activity & parasympathetic system - decreases bodily activity
What is the sympathetic nervous system
- involved in the fight/flight response
- in a scary situation the sympathetic nervous system prepares you to stay and attack or to run away
- it does this by increasing bodily activity
What is the parasympathetic nervous system
- maintains normal bodily activity via homeostasis
- rest and digest
- acts as a break and reduces the activities of the body that have been increased by the sympathetic nervous system
What is the process of synaptic transmission (11 steps)
1) the cells resting state is a negative charge, a stimulus activates the neuron
2) action potential occurs and an electrical impulse is created
3) electrical impulse travels down the axon of the neuron
4) impulse reaches the synaptic terminal of pre synaptic neuron
5) triggers vertices filled with neurotransmitters to move to edge of membrane of pre synaptic neuron
6) neurotransmitters are released into synaptic gap
7) neurotransmitters diffuse across the synaptic gap
8) neurotransmitters bind to receptors in post synaptic neurone membrane
9) triggers an electrical signal to be sent down the post synaptic neuron
10) neurotransmitters left in synapse are taken back to pre synaptic neuron
11) vestibules in pre-synaptic neuron will be refilled with neurotransmitters ready for next electrical signals
What are the effects of neurotransmitters
Can have one of two effects:
- have either an excitatory or inhibitory response which effects neighbouring neurons
What is an excitatory effect
Makes it more likely that the next neuron will fire
- when the neurotransmitters bind to the receptors on the post synaptic membrane, post synaptic neuron becomes positively charged and an action potential is created
What is an inhibitory effect
Makes it less likely that the next neuron will fire
- when the neurotransmitters bind to the receptors on the post synaptic membrane, post synaptic neuron becomes negatively charged and an action potential is not created
