Nervous System Flashcards
What are the two main parts of the nervous system?
Central nervous system and Peripheral nervous system
What are two parts of the CNS?
Brain and Spinal cord
What are two parts of the PNS?
Autonomic NS and Somatic NS
What are two parts of the Autonomic NS?
Sympathetic and Parasympathetic
What are two parts of the Somatic NS?
Sensory (afferent) NS and Motor (efferent) NS
What is the Sympathetic NS?
Fight or flight/ stress response
- Heart beats fast
- Breath is fast
- Pupils dilate
- Blood rushes away from brain
- Hormones rush through body
What is Parasympathetic NS?
Calming/ relaxation response
- Heart beat in slow, rhythmic pattern
- Breath is full and slow
- Pupils shrink
- Gut is active
- Increased blood flow to gut, lungs and brain
What does the lower spinal cord do?
Communicates with brain and lower parts of the body
What does the upper spinal cord do?
Communicates with brain and upper section of the body
What does the autonomic nervous system do?
- Regulates function internal organs/ some muscles
- Involuntary responses (eg. blood vessels changing size, heart rate change)
- Parasympathetic/ sympathetic
What does the somatic nervous system do?
- Voluntary responses - mainly skeletal muscle
- Motor neurons communicate messages from CNS to muscles we want to move
What is the Sensory NS nerves called and description?
Afferent Nerves
Body –> brain/spinal cord
- Made of sensory neurons that inform CNS about our five senses
What is the Motor NS neurons called and description?
Efferent Nerves
Brain –> body
- made of motor neurons responsible for voluntary movements eg. walking
What are neurons?
Cells that transmit messages back and forth from CNS to parts of the body. Helps the body to receive, interpret and respond to information.
What are the four main parts of a Nueron?
- Dendrite
- Cell body
- Axon
- Axon terminal
What is a Dendrite?
Branches off the soma (cell body) and receives information from other neurons.
What is a Soma (cell body)?
Controls metabolism and maintenance of the neuron and receives messages from other neurons.
What is an Axon?
Extends from the soma and carries information towards the cells that communicate with that neuron.
What is Myelin?
Insulating layer around axon that helps transmission of information.
Axons with myelin are white (rather than grey).
Protects the axon from chemical and physical interference, insulates the axon, enables information to travel faster.
Schwann cells create myelin
What are Axon Terminals?
At the end of the axon.
Branch and transmit messages to the next neuron.
Have sacs that secrete a chemical called a neurotransmitter when the electrical signal reaches this point.
Link one neuron to the dendrite of the next neuron.
What are the Nodes of Ranvier?
Gaps in the myelin sheath that allow rapid movement of signals.
What is the process of synaptic transmission?
- Action potential reaches axon terminal
- Vesicles containing neurotransmitters are released
- Neurotransmitters diffuse across synapse to bind to receptors on postsynaptic membrane
- Action potential travels to postsynaptic neuron
What are the three parts of synaptic transmission?
- Presynaptic terminal
- Synaptic cleft
- Postsynaptic terminal
What is the Presynaptic terminal?
Contains neurotransmitters, mitochondria and other cell organelles.
What is the synaptic cleft?
The space between the presynaptic and postsynaptic terminals.
what is the postsynaptic terminal?
Contains receptor sites for neurotransmitters.
What is the process of somatic neurotransmission?
1.Stimulus
2. sensory/ afferent nerves (receptor)
3. Processing center (spinal cord/ brain/interneuron)
4. Motor/ efferent nerves (effector)
5. Response
What is an interneuron?
Neurons that process what you are experiencing in between the receptor and effector/ motor
