PSYC100-Module 4

How to neurons communicate?

- Through impulses
- Within a neuron, electrical impulses 
- Between neurons, chemical messages

What are adrenal glands?

- Above kindeys 
- Often referred to as the ‘master gland’ of the endocrine system because many of the hormones it releases stimulate and thus regulate the hormonal action of other endocrine glands
- Secretes adrenaline and cortisol for stress response

What are agonists?

A substance the acts like or MIMICKS a neurotransmitter and binds to its receptor site. Replicate natural neurotransmitter.

- It FITS into the binding site 

What are antagonists?

A substance that BLOCKS or prevent the NATUAL neurotransmitter from activating and binding to its receptor site. Prevent natural neurotransmitter

What are dendrites?

- Branch-like extensions of the neuron that receive information from other cells.
- Message goes from dendrites down to the axon
- Where chemcial messages from the presynaptic neuron axons reach on the post-synaptic neuron

What are endorphins?

- Managing pain control and positive emotions 
- Chemicals in the brain similar to morphine that elevate mood and reduce pain

What are epinephrine?

- Also known as adrenaline 
- Emotional arousal, memory

What are excitatory neurotransmitter?

- Increase the chances of a neuron firing 
- Glutamate is an example 

What are gonads?

- Located in testicals or ovaries 
- Involved in sexual development 
- Secretes testosterone, estragon/progesterone

What are hormones?

- Chemicals secreted directly into bloodstream by endocrine glands 
- Chemical messengers

What are inhibitory neurotransmitters?

- Neurotransmitters than decreases the chances of a neuron firing
- GABA is an example

What are interneurons?

- Found within the central nervous system 
- Connects neurons with each other 
- Found in brain and spinal cord 
- Involved in decision making 
- Links sensory to motor 

What are motor neurons?

- Allows for the contraction of muscles causing voluntary and involuntary actions 
- Know as efferent neuron
Found in PNS
- Receives message from interneuron

What are neuromodulators?

- chemical messengers in the brain that  impact multiple neurons, multiple synapses

- Effects are slower but longer lasting 

-A subset of neurotransmitters

What are neurotransmitters?

Chemicals that transmit information between neurons, allows for communication between neurons 

work locally, meaning only impact the post synaptic neuron

fast but not long lasting 

Characteristis of neurotransmitters include: 

- bind to receptor sites 

- Maybe broken down by specific enzymes in synpatic cleft

- May undergo reuptake at pre-synatpic button, so presynatic neuron terminal buttons take up the remaining neurotransmitters left in the cleft

What are nodes of Ranvier?

- Periodical gaps down the axon where there are no mylin sheaths
- Helps in the transmission of the electrical signal down the axon body 

What are norepinphrine?

- A small molecule
- Involved in attention, arousal, learning, memory, dreaming, emotion and stress
- A hormone that triggers physiological arousal, particularly in potential danger situations
- Deficienty of norepinphrine causes depression
- Excess of norepinphrine leads agitated, manic states. 

What are some examples of neurotransmitters?

• Glutamate

• GABA

• Dopamine

• Serotonin 

• Acetylcholine

• Endorphins

• Epinephrine 

What are terminal buttons?

• Found at the end of the axon buttons, when sends a chemical message to another neuron.

• These chemical signals or messages (neurotransmitters) are released due to the incoming electrical message that came from the axon

• These Terminal buttons, when activated by the electrical impulse, release these neurotransmitters into the synapse  

What are the structures of a neuron?

- Dendrites 
- Soma or cell body 
- nucleus 
- Axon 
- Mylin sheath 
- Nodes of Ravier 
- Terminal buttons 
- Synpase/ synpatic gap

What are the types of neurons?

- Sensory 
- Interneuron 
- Motor

What is a graded potential?

- Spread of voltage changes along the cell membrane when neuron is exicted by the cell 
- But unless it meets the threshold, it will not fire
- Although change in voltage, the neuron is not firing, but getting ready, or increasing the chances

What is a neuron?

A cell that makes up the nervous system 

What is a resting potential?

- When there is no neural impluse, or electrical impluse travelling down the neuron from dendraites to axon 
- At a resting potential the cell is MORE NEGATIVE than the OUTSIDE of the cell
- Condition in which the neuron is not firing
- At resting it is -70 mV

What is a sensory neuron

-Receive information from sensory cells (receptors) can carry that to the brain. Found in PNS

- Know as afferent

What is acetylcholine?

- A small molecule 
- A neurotransmitter involved in muscle contractions, learning and memory.
- Involved in memory and movement, learning, attention and sleep 
- Malufunction or deficincy in acetylocholine leads linked to Alzheimers 

What is adrenaline?

- A hormone 
- A hormone that triggers physiological arousal, particularly in potential danger situations.
Secreted by adrenal glands

What is an action potential?

- A temporary shift in the polarity of the cell membrane, which leads to the firing of a neuron
- The change of voltage in response to a stimulus 
- Voltage HAS to reach -55 for the neuron to fire, if lower than -55 will not fire, it is an all or nothing type or reaction 
- The stimulus has to be strong enough to trigger an action potential 

Here is the process 
- The sodium from outside the cell, come INTO the cell making it less negative, so now the cell is more positivly charged (Depolrisation)
- Once the cell positvity reaches 30 mV, the cell's charge will reduce 
- K+ leave the inside of the cell, making it more negative again, so process going back to being more negative than the outside is repolarisation. 
- Repolarisation keeps on happening to a point where the cell's charge goes below -70 mV
- Becoming super negative is known as hyperpolarization

- When activated by stimulus, sodium rushes INSIDE the neuron, and becomes less negative, depolarisation 
- Actional potential is activated, and travels down from start of axon to terminal buttons
-  

What is an impluse?

- An all or nothing reacation 
- Actional potential and what happens is always the same regardless of the stimulus 
- What is different is the magnitude, so the varying RATE of reaction 
- Stonger stimulus the faster the action potential occurs

- Down the axon it is electrical 
- Between neurons it is chemical 
- Pre synaptic sends signal 
- Postsynpatic reieves the signal 

- The electrical impluse causes the terminal buttons on the persynaptic neruon to send out neurotransmitter into the synpatic cleft to be taken up into the dendrites of the post-synaptic cell 

What is depolarisation?

- When the inside of the cell (such as the dendrites for a neuron) BECOMES LESS NEGATIVE, so MORE POSITIVE, than the OUSTIDE OF THE CELL
- When NA+ comes into the neuron

What is dopamine?

- A small molecule
- A neurotransmitter with wide-ranging effects in the nervous system, involved in thought, feeling, motivation and behaviour.
- In movement and reward 
- Over supply, excess: Schizophrenia
- Undersupply: Parkinson's disease

What is GABA?

- In an amino acid neutransmitter 
-Involved in sleep, movment and regulation of anxiety 
- A neurotransmitter with wide-ranging effects in the nervous system, involved in thought, feeling, motivation and behaviour.
- An inhibitory neurotransmitter, decreases the chances of neuron firing
- Undersupply: seizers and insomina 
- Oversupply: Increase inhibitory effect, thus reduce anxiety, Huntingtons disease

What is Glutamate?

- Amino acid neutransmitter
- An exictatory neutransmitter- increase the chances a neuron fires
- Involved in memory and learning
- One of the most widespread neurotransmitters in the nervous system, which largely plays an excitatory role; also called glutamic acid.
- Low levels linked to anxiety, depression, migraines and seziures, damage after stroke

What is hyperpolerisation?

- where a cell's membrane potential becomes more negative, essentially making it harder to trigger an action potential or other electrical signal
- 

What is noradrenaline

- A hormone that triggers physiological arousal, particularly in potential danger situations

What is oxytocin?

- A hormone released by pituary gland
- Curcial role in bonding, reproduction and social behaviour 

What is postsynaptic potential

- Impacts the postsynpatic neuronm, so the neuron reieving the message 
- It is the postsynaptic neurons voltage change at the binding sites on the denrites caused when a neurotransmitter binds to it binding site 
- Positve voltage shift: Increase chances of postynpatic neuron firing: Exhitatory
- Negative voltage shfit: Decrease chances of postsynaptic neuron firing: Inhibitory 

What is reporlisation?

- When the neuron becomes more negative
- Happen after the action potential, when K+ flow OUT of the cell, when positive leaves the cell
- Inside is usually more negativly chraged, both inside and outside are negativly charged, but inside is more negatlivliy charged
- the process of restoring the resting membrane potential of a cell after it has been depolarized 

What is serotonin?

- A small molecule
 - Involved in mood, appetite, impulsivity, arousal, emotional states, sleep 
- Undersupply: linked the depression 

What is synaptic pruning

- Connections or synpases between neurons are not used, if that pathway not used, these less active synapses are removed

What is the absolute refectory period?

- Minimum time before another action potenital, usual 1 or 2 milliseconds 
-At that peak on the graph 
- Right when the action potential occurs 
- When depolairsation and repolarisation is occuring, it is the ABSOLUTE refactory period 
- During the abolsute refacotry period, no stimulus can cause that neuron to undergo another action potiental 
- Cannot have another action potienatal initated during this time

What is the axon?

- Long extension from the cell body, carries the electrical information away from the dendrites towards the axon terminals
- Where the electrical impulse is carried down

What is the baseline voltage, what is the threshold, when its is depoliaristiom, repolisation and hyperpolisation?

What is the cell body?

Cell body, where the nucleus is contained 

What is the endocrine system?

The collection of ductless glands that secrete hormones into the bloodstream and control various bodily and psychological functions.
- Involves hormones

What is the meylin sheath?

- A tight coat of cells composed primarily of lipids, which serves to insulate the axon from chemical or physical stimuli that might interfere with the transmission of nerve impulses and speeds neural transmission.
- Insulates, protects and makes the electrical implus more efficent and faster
- Degredation of mylein sheath leads to MS, because messages cannot be relayed down the neuron

What is the nucleus?

Where genetic information is stored, also determines how the particular neuron will manipulate the input of the dendrites 

What is the pituitary gland?

- Often referred to as the ‘master gland’ of the endocrine system because many of the hormones it releases stimulate and thus regulate the hormonal action of other endocrine glands
- A gland in the brain and connect to nervous system, but part of the endocrine system, that release hromones that causes a chain reaction that causes other glands to release hormons

What is the polarity during relative refactory period?

What is the polarity during relative refactory period?

What is the polarity of a neuron at resting potential?

- It is more negative than the outside

What is the polarity of a neuron during an action potential?

- During the action potential at the start it is depolarised 
- Meaning it chas become less negative 
- More positive than before the action potential
- Then after it is repolarisewd, meaning it becomes back to being more negative

What is the relative refactory period?

- During hyperpolaristion
- Unlikey for an action potenital to occur 
- Need a stong stimulus to trigger an actional potential to happen

What is the synapse?

The gap between two neurons, where neurotransmitters are released 

What is thyroid gland?

- Found near neck
- Involved in growth and metabolism, energy levels and mood 
- Underactive: depression, weight gain, sluggish behaviour 
- Overactive: Weightloss