W2: Nervous System Flashcards
What does the Central Nervous System (CNS) consist of?
- Consists of the brain and the spinal cord
What does the Periphal Nervous System (PNS) consist of?
- Consist of everything else expect the brain and spinal cord
CNS
The cortex of the brain is responsible for… (4)
- Processing information
- Synthesis info from outside world and comparison
- Output and action
- Central executive
CNS
What is the prenatal cortex of the brain responsible for?
Decision making
Hypothalamus function - subcortical structures (2)
- Maintains homeostasis
- Stimulates the pituitary gland
PNS has two divisions - (2)
- Somatic Nervous System
- Autonomic Nervous System
PNS
What is the responsibility of the somatic nervous system?
To respond to the external environment
PNS
What is the function of the somatic nervous system? (2)
- It controls motor neurons that operate skeletal muscles
- It is associated with the voluntary control of body movements via the use of the skeletal muscles
PNS
Autonomic Nervous System (2)
- Controls and regulates (expand/dilate/constrict) smooth muscles that are in the stomach, blood vessels, heart etc
- The autonomic nervous system is associated with involuntary movements
Two divisions in the autonomic nervous system (ANS) are..
- Sympathetic nervous system
- Parasympathetic nervous system
Sympathetic nervous system
Parasympathetic nervous system
The organism experiences a major stressor in the enviroment
Sympathetic nervous system
Two neurotransmitters primarily associated is…
epinephrine and norepinephrine
Sympathetic nervous system
Activates the body to help cope with demands (e.g., stress) which makes the body.. (5)
- Increases pulse, heart rate and respiration to provide the body with resources (primarily oxygen and glucose)
- The blood pressure increases which shifts blood supply towards internal organs
- Pupils dilate
- Reduces digestive activity
- Sweat is also released to cool a body which heats up
Neurotransmitter associated with the parasympathetic nervous sytem is
Acetylcholine
Parasympathetic nervous system or also known the rest and digestive
Function (3)
- Slows activity of organs to conserve energy for future use
- Also activates digestion to renew energy
- Increases digestive functions and sexual appetite
When the sympathetic nervous system is more active, the parasympathetic system is
less active
The body is constantly fluctuating between the
sympathetic and parasympathetic nervous system
While breathing in (taking oxygen into the lungs)
The parasympathetic influence is removed temporarily which (2)
- Inhibits the influence of the vagus nerve
- Heart rate accelerated briefly (influence of sympathetic nervous system)
Why is heart rate increasing advantageous when breathing in?
To bring in newly oxygenated blood in the blood stream
What is the vagnus nerve?
(bundle of axons that go down the spinal cord that responsible for parasympathetic functions)
When breathing out, the parasympathetic influence is active! (2)
- The vagus nerve inhibits the sympathetic activity
- Heart rate decreases as a result
Capture individual differences in the fluctuation of influence between the sympathetic and parasympathetic nervous systems with
- Heart rate variability (HRV) OR also known as respiratory sinus arrhythmia (RSA)
There are individual differences in fluctuation in heart rate at rest
The larger the fluctuations (breathe in and large acceleration of heart rate and large spread between heartbeats) - (3)
Constantly switching between sympathetic vs parasympathetic activation
More advantageous as easily able to adapt to new situations
Therefore better coping with stress
If someone has a static and constant heart rate as they have a huge influence of the parasympathetic activity
If they are put into a stressful situation , can be longer for them to
Adjust and switch to the sympathetic nervous system to cope with that stress
Diagram of heart rate variability in ECG
- Spread out is exhaling and heart peaks in breathing in
SAM axis stands for the
Sympathetic-Adrenal-Medullary axis
SAM axis stimulates the
sympathetic nervous system (fight/flight)
SAM axis is quick to stimulate sympathetic nervous system as (2)
uses bundles of the nerve that go down along the spinal cord
As electrical impulses go down the spinal cord its active
SAM axis stimulates hormone release
Stimulates hormones such as (2)
- Adrenaline
- Noradrenaline
Norepinephrine is a neurotransmitter
Hormone equivalent
Noradrenaline
Epinephrine is a neurotransmitter
Hormone equivalent
Adrenaline (immediate burst of energy that occurs for a short time)
SAM axis is activated initally for
short-term response to stress
SAM axis fights against the
vagus nerve
Vagal tone is the influence the body currently has over the
vagus nerve
Vagus nerve is in direct competition with the
SAM axis
Vagal tone stimulates the
parasympathetic nervous sytem (rest/digest) system quickly with electrical impulses going down the spinal cord
Vagal tone stimulates the release of acetylcholine which
Used for (smooth) muscle movement (e.g., stimulate stomach to do its job and get resources like glucose to store it for later)
(HRV) is the difference between the
vagal and SAM activity
Diagram of the Organisation of the Nervous System
Sam axis, vagus nerve, sympathetic and parasympathetic affect
the cardiovascular system
Stress impacts 2 important aspects of the cardiovascular system
Heart Rate
Blood pressure
Influence of heart rate and blood pressure depends (2)
on appaisal of stress
So activation of SAM axis or HPA axis depends not only on biological but psychological perception on the stressor
