Week 6 Flashcards
Nervous Networks
- Consists of interconnected neural cells
- Brain learns by modifying certain connections in response to feedback
Central Nervous System
- Brain and spinal cord
- Occupies central location in the body
- Producing and maintaining behaviour
- Encased in skull and spinal column
Peripheral Nervous System
- Outside Brain and Spinal Cord
- Allows the CNS to communicate with the wider body
Somatic/ Skeletal Nervous system
- Transmits sensory signals and motor signals between the CNS and skin, muscles and joints
- Tells muscles, joints etc to do action
Autonomic Nervous System
- ‘Self governing’ system of PNS
- Transmits sensory and motor signals between CNS and glands and internal organs of the body i.e. heart, stomach etc.
- Controls functions such as crying, sweating, secreting some hormones
Sympathetic Activation
- Controls activities that support the arousal of the body and expenditure of energy
Components of sympathetic activation
- Blood sugar increases
- Heart rate increases
- Blood flow diverted to heart and muscles
- Airways dilate; rapid breathing
- Perspiration
- Elimination of digestion
What Triggers Fight or Flight
- Most commonly triggered by life threatening or emergency situations
- Also associated with anxiety and thrill seeking activities i.e. roller coaster or watching a scary film
- Essential evolutionary need
- Not a conscious decision and is automatic so cannot be controlled
Freezing
- Fight/ Flight on hold while you further prepare yourself to protect yourself
PTSD
-Irregular levels of stress hormones, leading to increased adrenaline
- Manifests itself in hyperarousal
- Fight/ Flight as a reflexive trauma response or an automatic trigger of trauma related reminders
Parasympathetic Activation
- Works to relax the body and reduce the expenditure of energy
- Pupils contract, heart rate slows, breathing slows etc
Spinal Cord
-Carries sensory info to brain and motor info from brain
- Co-ordination of simple reflexes i.e. withdrawal reflex
- Limited analysis
Grey Matter
- Dominated by presence of cell bodies or somas
- Forms a butterfly shape
- Mainly found closer to the outer cortex of the brain
- Interior of spinal cord
- Volume production completed at age 8
White Matter
- Tissue type consisting mainly of axons and fatty myelin sheaths that surround them
- Found closer to the centre of the brain
- Found on outside of spinal cord
- Doesn’t complete production until late 20s
Multiple Sclerosis
A chronic, inflammatory disease of the CNS which gives rise to focal lesions in grey and white matter
Focal Lesions
Concentrated, damaged spots
Demyelination
- Immune system becomes overactive and mistakes healthy myelin as a threat to the body
- If myelin sheath is damaged, the axon is exposed and can be damaged
- If a neuron dies, it cannot be resurrected
White Matter
- Responsible for 20% of strokes worldwide
- Causes issues with memory, balance and mobility
What happens with white matter disease?
-Affects blood vessels within white matter
- Blood vessels harden, preventing O2 and nutrients reaching white matter
- Can cause neurons to die
Spinal Cord Injury
- When axon bundle in the spinal cord is lost, the connection between the brain and spinal cord grey matter is lost
- Can cause paralysis and sensory issues, often permanent
Spinal Cord Injury and Paralysis
- Compressing spinal cord injury can lead to paralysis as the info from the brain’s motor cortex can no longer reach the spinal cord and muscles
Excitotoxicity
- After spinal cord injury, neurotransmitter release can be heavily impacted, causing too much release of chemicals
- As neurons are activated by neurotransmitters, they become overactivated and damaged
Major Depression’s links to CNS
- Grey matter loss in structures such as the hippocampus (storing memories) and the amygdala (processing emotions)
Schizophrenia
Decreased grey matter in structures such as the striatum
