Sac 1 Flashcards
What is the role of the Central nervous system?
CNS: Composed of the brain and spinal cord
- Receives and interprets info from PNS, processes a response and then responds.
- Uses motor neurons to convey info to the PNS through efferent tracks
What is the role of the PNS?
PNS: Carries sensory info from sensory organs and internal organs to the CNS via afferent tracks.
- Also carries info from CNS to muscles, organs and glands via efferent tracks.
The brains role…
Regulates and guides all other parts of the nervous system
Spinal cord role…
Transmits sensory/afferent messages towards the brain and motor/efferent messages away from the brain to PNS
The Synonym for neurons
SAME: Sensory Afferent Motor Efferent
The PNS is divided into which two nervous systems?
The somatic and the autonomic nervous systems
What is the role of the Somatic NS? (voluntary)
Relays info to and from the CNS, and the skin and skeletal muscles e.g.. Waving, clapping etc
Whats is the role of the autonomic NS? (involuntary)
Relays info to the internal organs e.g.: heart, lungs digestion
Which two NS is the Autonomic NS divided into?
The Sympathetic and Parasympathetic NS
The role of the Sympathetic NS
Controls organs in times of stress. It releases adrenalin, increases heart rate and respiration and dilates pupils to enable better vision.
activates FFF: Fight Flight- Freeze response
The role of the parasympathetic NS
Controls organs when body is at rest.
counterbalances the sympathetic NS by returning body to a state of calm (homeostasis) once the cause of stress or the threat is no longer present. Maintains Homeostasis
What is a conscious response?
A conscious response or conscious awareness occurs willingly and is consciously controlled (Somatic NS functions) e.g.. Talking, waving hand.
What is an unconscious response ?
An Unconscious response or unconscious awareness occurs automatically and “Unconsciously” (Autonomic NS function) e.g.. Breathing, stomach contractions, heart beating.
What is a Spinal Reflex, or Reflex arc?
It is an autonomic response that is initiated via neurons in the spinal cord instead of the brain. It is a survival response, activated when in danger/threat of harm (e.g.. Burns, cuts stings etc) so that the amount of damage done to the body is minimised. Sensory neurons from sense organ fire upon an afferent tract to the spinal cord where interneurons then interpret the impulse to the motor neurons which then fire to the appropriate muscle to move the body part away from harm (this happens very quickly) the sensory message is still transmitted to the brain and is then registered as painful so that the experience will be remembered and hopefully learned from (this takes slightly longer than the reflex arc).
What is the role of the neuron?
The Neuron is the basic building blocks of NS
- The function of a neutron is to communicate info around the body
- Sensory neurons (afferent, PNS to CNS)
- Interneurons ( communicate between sensory and motor)
- Motor neurons (efferent, from CNS to PNS)
- Neural health is critical for optimal functioning
The parts of the neutron and their function
Dendrites: Receives incoming neural messages
Soma: Body of the neuron, contains nucleus and genetic material of neuron
Axon: Pathway neural message travels along
Myelin sheath: Fatty tissue that incases axon to protect and aid in the speed of transmission.
Terminal buttons: Releases chemical known as neurotransmitters to a receiving neuron for communication, aka synaptic knobs
What is the process of neuron communication classified as ?
Electrochemical : in the neuron its electrical and between neurons its chemical
Explain resting and action potential…
Resting potential : is when a neuron is not activated, negatively charged ions are inside the axon and positively charged ions on outside.
Action Potential: Is when an electrical impulse, neural impulse, (aka action potential) travels through the axon. The ions on the inside go from negatively charged to positive and the outside from positive to negative as the neural impulse passes through.
Action potential is an all or nothing process.
Refer to notes for diagram.
what is the lock and key process?
When neurotransmitters are released across the synapse they locate the specific receptor sites and “unlock” their potential, if they bind with them the post synaptic neuron is either activated (excitatory) or inhibited (inhibitory).
What do excitatory neurotransmitters do? and an example of a prominent excitatory neurotransmitter
They stimulate or activate post synaptic neurons to perform their functions e.g.. Glutamate
what is the role of the neurotransmitter glutamate ?
Glutamate allows synapse change so that memory, learning and cognition can occur.
What do inhibitory neurotransmitters do? Provide an example of a prominent inhibitory neurotransmitter
They block or prevent postsynaptic neurons firing e.g.. GABA
What is the role of the neurotransmitter GABA?
GABA : Decreases anxiety and plays minor role in motor control and vision
What is the role of neurotransmitters?
Neurotransmitters are chemical substances produced by a neuron that carry a message to other neurons or cells in muscles, organs or other tissue.
What is the process of re uptake?
Neurotransmitters that do not bond to a receptor site are broken down by enzymes and absorbed back into the terminal button of the pre synaptic neuron.
What are Chronic - (Persisting for a long time or constantly re occurring) - nervous system changes
They are persisting for a long period or constantly re occurring changes that effect the function of the NS due to interference of neurotransmitters function- This is illustrated by role of GABA in Parkinson’s disease.
Why does neurotransmitter interruption occur and what are causes ?
Can occur from an Imbalance or deficiency in a particular type of neurotransmitter and can be naturally occurring or self induced.
Causes: Alcohol and drugs - Imitate Dopamine function
Diet and Nutrition: e.g. Vit B (folic acid) deficiency
Stress
Genetics
What are the side effects of Neurotransmitter interruption ?
The side affects can be short term (temporary) or permanent (Chronic) and they all relate to the type of neurotransmitter being impacted: Mental disorder Addiction Immobility Weight loss
What is Serotonin?
Serotonin is an Inhibitory Neurotransmitter Involved in stabilising mood
Deficiency results in emotional disturbances which lead to schizophrenia
What is Dopamine
An Excitatory neurotransmitter That helps control bring pleasure centre as well as movement and emotional responses.
Deficiency: Can suffer from depression but also Parkinsons disease and may also be more prone to addiction.
What is parkinson’s Disease?
It is a Progressive neurodegenerative disorder characterised by both motor and non motor symptoms
What cause motor symptoms in Parkinson’s and what are some examples? (dopamine)
Motor symptoms result from degeneration and loss of neurons in the substantia nigra - located in mid brain- ( the part of brain that produces Dopamine), so when this is damaged the level of dopamine decreases.
This results in inhibited motor control which leads to stiffness, rigidity and slow movements
What are some non motor symptoms in Parkinsons?
Decrease in sense of smell ( anosmia) and problems with cognitive function occur, have trouble speaking
What are Tremors caused by in Parkinson’s ?
When the amount of Dopamine Decreases in people with Parkinson’s, so does the amount of GABA- Particularly in the sub thalamic nucleus of the brain- (the inhibitory neurotransmitter, which stops the messages being fired) which causes the neurons to impulsively fire resulting in muscle tremors.
