W1L1 - Introduction Flashcards

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1
Q

What is the difference between the signals trasmitted by neurons and synapses

A

Neurons: Cells in nervous system

  • Electrical signals “Action Potential” trasmitted along axon

Synapses: Neurons meet

  • Chemical signals “Neurotrasmitters” trasmitted between neurons
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2
Q

How do neurons in the CNS, PNS, ENS communicate? What happens if they don’t have it?

A

ALL neurons communicate via. NT/NM

  • Modulate neural activity
  • Synaptic plasticity (i.e. building new synapses/alter function of old synapses)

Without these chemical signals (NT/NM)

  • Action of a neuron would not influence any other neuron
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3
Q

Difference between NT and NM

A

NT:

  • Excitatiory/Inhibitory
  • Rapid (ms)
  • Precise
  • Point-to-point

NM:

  • Slower (ms-s) that alter subsequent processes of neurons
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4
Q

How many neurons are there in the CNS

A

100 billion neurons in the CNS

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5
Q

What are hormones

A

Signaling molecules produced by glands and transported through the blood to regulate physiology (muscles, neurons etc) and behaviour.

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6
Q

4 differencses between NT and hormones

A

NT

  • Nervous system
  • Tramission between neurons (Across synapse)
  • Target cells can be specific neurons or other cells
  • Generally fast (ms), though sustained NT release can lead to more sustained changes in brain

Hormones

  • Endocrine system
  • Travel by blood
  • Target cells can be some distance from endocrine gland
  • Much slower, ranging from few seconds to days
  • Also directly modulate NT levels and function
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7
Q

What is the blood-brain barrier? (Location, Function)

A

Location

  • Exists within 600km of blood vessels in the CNS

Function

  • Prevents many substances from passing between blood and brain.
    • Dugs, natural chemicals and foreign infections cant pass through (but is not perfect – small amounts of many things still get through).
  • However, multiple other avenues for controlled passage between blood and nervous system exist.
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8
Q

What is the PNS (Location, Function)

A

Location

  • Nerves and glanglia outside of the brain and spinal cord

Function

  • Receives sensory information about body position, pain and temperature etc
  • Sends messages from the brain to control muscles and movement.
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9
Q

What is the ENS. Locaton, how many neurons, properties, function

A

Location

ENS (2nd brain) is part of the PNS

How many neurons

  • Contains 100million neurons

Properties

  • Has its own reflexes and senses and can act independently of the brain
  • Does not engage in consciousness, philosophy, decision-making despite being so much like our “main” brain.
  • Only part of the PNS that can act autonomously
  • Nearly every neurotransmitter found in the brain is also found in the gut
    • 95% of all serotonin is found in the gut
    • Does not just help digestion
  • 90% of connections between the brain and gut go from the gut to the brain.

Function

  • Helps digestion
  • Plays a major role in emotions & stress (butterflies in our stomachs) & also clinical depression / anxiety.
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10
Q

What are the 3 systems in the gut-brain interaction (And elaborate)

A
  1. Peripheral Serotonin
    * Cells in gut produce serotonin, effecting on brain
  2. Immune System
    * Intestinal microbiome prompts immune cells to produce cytokines, effecting neurophysiology
  3. Bacterial Molecules
    * Microboes produce metabolites (e.g. butyrate), effecting activity of cells in blood-brain barrier
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11
Q

What is microbiome and microbiota

A

Microbiome

  • Combined genetic material of microbiota
  • > 100 times more genes than the human genome

Microbiota

  • Trillions of bacteria and other microorganisms in the gut
  • Impacts brain, behaviour, cognition
    • Shy mice became “adventurous” after receiving gut microbiota transplant from social mice
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12
Q

How does the gut microbiota influence the brain, and how does the brain influence the gut (neurophysiologically)

A
  • Gut microbiota modulates development and homeostasis of the CNS through immune, circulatory and neural pathways.
  • The CNS impacts the gut via neural and endocrine response
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13
Q

What is the link between sickness behaviour and brain

A

Bidirectional link between brain to immune and immune to brain

Activation of the immune system due to illness triggers a series of temporary behavioural, cognitive and emotional changes including:

  • Fever
  • Increased sleep & general lethargy
  • Depressed mood
  • Hyperalgesia (increased pain sensations)
  • Loss of interest in usual activities
  • Anorexia (reduced appetite)
  • Decreased social interaction
  • Impaired concentration
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14
Q

What is sickness behaviour belived to be triggered by?

A

Triggered by cytokines released by the body in response to infection and travel to the brain

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15
Q

What are cytokines and what are some properties?

A

Cytokines

  • Group of small proteins important in cell signaling
  • Released by cells and influence behaviour of other cells
  • Too big to pass through the blood-brain barrier
    • Believed to enter the brain indirectly or trigger new cytokines to be released within the brain.
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16
Q

In experiments where volunteers were injected/infected with the common cold, what do they show impaired performance on? What do people with more severe illness have?

A

Impaired:

  • Visual detection
  • Hand-eye coordination
  • General cognitive tasks
    • More accidents are found to occur at work when employees are sick.

People with more severe illness had:

  • Negative mood
  • Fatigue
  • Memory
  • Attention
17
Q

What is the evolution theory proposed behind sickness behaviour? What is the theory behind excessive sickness behaviour? What else can it trigger?

A
  • Organised strategy evolved to conserve energy and improve the fight against infection
  • Excessive sickness behaviour (and cytokine release) > neuropsychiatric syndromes (fatigue/MDD). Theory is based mainly on overlapping symptoms and is still speculative.
  • Cytokine release can also trigger “the stress response” and stress can be linked to changes in immune function
18
Q

What is an example of our integrated brains

A

Kissing

  • Increases risk of transmitting illness
  • Allows transfer of hormones like testosterone to passed on to directly increase arousal
  • Others suggest it is a show of trust and close bond (either between the individuals or to the public)