Psychology Final Exam V2

Nervous System Def

The nervous system is a complex and highly organised network of specialised cells, formed from neurons and glia

function of the Autonomic NS

that is responsible for the involuntary and autonomous regulation of the body's visceral muscles, organs, and glands.

What is the primary function of the nervous system?

To enable the brain to receive information from both internal and external sources and respond accordingly.

What are the two main components of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS).

What does the Central Nervous System (CNS) consist of?

The brain and spinal cord.

What is the function of the CNS

1.

Coordinates incoming sensory info and initiates outgoing motor responses

2.

Unconscious and conscious responses/ voluntary and involuntary and reflexes

3.

Receives info from Peripheral NS, sends a response to Peripheral NS

Brain Def

The brain is an intricate network of cells that plays a vital role in processing information received through neural pathways from the body and in directing actions within the body

Function of the brain

Receives, Integrates and initiates a motor response

Regulates and guides all parts of NS

regulates vital body functions unconsciously -> breathing heart rate

responsible for higher order functions and origin of emotions, personality and humour

Communicates with body through spinal cord, nerves and cranial nerves

function of cranial nerves

Cranial nerves connect brain directly to organs and mucles

part of peripheral NS

Spinal Cord Def

A long, thin bundle of nerve fibres and tissues that extends from the base of the brain to the lower back and is encased by a series of bones called the vertebrae which extends further than the actual cord

Function of Spinal Cord

1.

Carry sensory information from body (PNS) to brain for processing

2.

Carry motor information from the brain to the body (PNS)

Exception for these two functions are during involuntary responses

Spinal reflex -> no input from brain

Where are sensory/motor info passed through

Afferent Tract (upwards) -> sensory

Efferent Tracts (downwards) -> motor

What happens when spinal cord is injured

If injured brain loses sensory input and control over the body

Higher up injuries in spinal cord are more severe -> greater no of nerve connections between brain and body disturbed

What is the role of neurons in the nervous system?

Neurons are responsible for communication within the nervous system.

What is the role of glia in the nervous system?

Glia support the functions of neurons.

What is in the Peripheral NS

Somatic System and Autonomic System and all neurons outside CNS

Peripheral NS Def

The peripheral nervous system is the complete network of neurons located outside the central nervous system that comprises of muscles, organs and glands

Peripheral NS function

Carries info to and from CNS

Afferent neurons (from sensory organs) -> CNS

Efferent neurons (from CNS) -> muscles

Somatic NS def

voluntary system that consists of both a voluntary sensory function and a voluntary motor function

Somatic NS function

Transmits sensory info (from receptor sites) -> CNS

- Info from CNS to the muscles that control movement

- Sends info to skeletal muscles (controls voluntary movement)

Autonomic NS def

Network of nerves that connects the CNS with the body's visceral muscles, organs and glands

What are the two branches of the Autonomic Nervous System?

Sympathetic Nervous System and Parasympathetic Nervous System.

What is biofeedback

a person receiving info about the state of an internal bodily activity that occurs automatically

How is biofeedback related to Autonomic NS

Autonomic NS doesn't need conscious effort to function

However conscious control can possibly be exerted over ANS (blinking)

This is done through a process called biofeedback

eg (learning techniques, monitoring devices)

What is the role of the Sympathetic Nervous System?

To prepare the body for vigorous activity or stressful situations by activating visceral muscles, organs, and glands.

- releases adrenaline from adrenal glands

- physiological function suppressed

- an arousing or activating system

Sympathetic NS def

Division of the NS that activates visceral muscles, organs and glands to prepare the body for vigorous activity or to deal with a stressful of threatening situation

What does the Parasympathetic Nervous System do?

Counterbalances sympathetic NS -> returns body to a state of calm once stress or threat is not present

Maintains homeostasis during periods of low stress (body's natural state of equilibrium)

Parasympathetic NS def

Division of the autonomic nervous system that keeps the body functioning effectively

What occurs when Sympathetic NS is active

Dilates pupil

Accelerates heartbeat

Inhibits digestion

Stimulates glucose release by liver

Stimulates secretion of epinephrine and norepinephrine

Relaxes bladder

Inhibits the erection of sex organs

What occurs when Parasympathetic NS is active

Contracts pupil

Slows heartbeat

Stimulates digestion

Stimulates gallbladder

Contracts bladder

Stimulates erection of sex organs

What happens if both the Parasympathetic and Sympathetic NS are active at the same time

If both are active -> one system dominates over the other

Usually, the parasympathetic system as it is involved in everyday functioning

Voluntary vs Involuntary Responses

Voluntary

Have control over -> involved in decision-making

eg. (Walking/speaking)

Involuntary

don't have conscious awareness

eg. (breathing/heart rate)

Conscious vs Unconscious responses

Conscious response

Voluntary, goal directed and requires a level of control

Controlled by somatic NS, involves CNS (spinal cord travel)

Unconscious response

Involuntary, unintentional, automatic

Regulated by Autonomic NS

Reflex Def

A reflex is a response to sensory stimuli that is unlearned and innate. These responses tend to be simple behaviours that contribute to our safety and survival

Spinal Reflex Def

An adaptive behaviour designed to keep us away from danger and harm. An automatic response initiated by interneurons in the spinal cord rather than the brain

- Unconscious, involuntary and automatically occurring response only to some stimuli (no brain involved)

Adaptive Behaviour Def

A behaviour that increases an organism's chances of survival

A response that helps maintain homeostasis (internal balance)

A behaviour that improves the ability to cope with the environment

A response that has survival value

Why is the spinal cord an adaptive behaviour

Produces an automatic rapid response

No conscious thought

Reduces injury/prevents harm

Process of a Spinal Reflex

1. Sensory stimulus detected by sensory receptors

2. Sensory neurons carry info via a sensory pathway to spinal cord (afferent)

3. Interneurons in spinal cord initiate an involuntary motor movement

4. Relayed to motor neurons and carried via a motor pathway to muscles (efferent)

5. Muscles perform reflex response without input from the brain

6. Sensory stimuli reach brain -> pain

Spinal Reflex benefits

1.

Pain can't be felt until messages reach brain even if motor response has occurred

Quicker response -> only if it enhances survival

- Thus, it is an adaptive response -> saves time in situations that can be dangerous -> increases survival

What does the Spinal Reflex demonstrate

The spinal reflex demonstrates that a response to a particular sensory stimulus can have both an unconscious and conscious component, one occurring before the other. For each reflex action, a handful of neurons simply convert a sensory stimulus into an action.

Neurons Def

is an individual nerve cell that is specialised to receive, process and/or transmit information to other cells in the body.

3 types of neurons

Motor Neuron receives messages from CNS -> sends to effector site

Sensory Neuron sends message towards CNS

Interneuron in the CNS

Parts of the Neuron

Axon

Dendrites

Myelin

Soma

Axon Terminals

Synapse

Axon function

single tubelike extension -> transmits neural info to other neurons

Dendrites function

detects and receives info from other neurons

Soma function

collects and integrates info before info is passed on

myelin function

white fatty substance of glial cells surrounds the axon

Insulates axon -> prevents interference from activity of other nearby axons

Axon terminal function

Stores and produces neurotransmitters into synaptic gap

Synapse definition

Space between two neurons in a neural pathway

What is the difference between communication within a neuron and communication between neurons?

Communication between neurons -> electrochemical process -> uses chemical energy

Communication within neuron -> electrical energy

Presynaptic neurons def

the neuron that release neurotransmitters from the axon terminals.

Post synaptic neurons def

the neuron that receives neurotransmitters through receptors on the dendrites.

Process of neurons firing

1.

Neural impulse reaches the axon terminals of the presynaptic neuron

2.

Causes vesicles to release neurotransmitters into the synaptic gap

3.

Neurotransmitters bind to receptor sites on the dendrites of the post synaptic neuron (lock and key process)

4.

Neurotransmitters than makes the

Post synaptic neuron more likely to fire (excitatory)

Post synaptic neuron less likely to fire (inhibitory)

Functions of a neurotransmitter

Excite neuron to fire

Inhibit neuron from firing

Neurotransmitter definition

Neurotransmitters are chemical messengers released by neurons to transmit signals to other neurons, muscles, or glands, enabling communication throughout the nervous system.

Excitatory neurotransmitter function

Increase likelihood of post synaptic neuron firing an action potential or neural impulse

Glutamate

Function of Glutumate

Essential for memory and learning

Enhances information transmission

Involved in perception thinking movement

How is Glutumate involved in learning

Stimulates structural and functional changes to connections between neurons

Glutamate is released when a neural pathway associated with an experience is activated or stimulated.

Inhibitory neuron function

decrease the likelihood that the post-synaptic neuron will fire an action potential or neural impulse

GABA function

Essential for motor control vision and decreasing anxiety

Maintains neurotransmission at an optimal level

Low levels associated with seizures anxiety and phobias

Without GABA too much postsynaptic neurons

Why does there have to be a balance of neurotransmitters in the brain

1.

need to be in balance

too much or too little of certain neurotransmitters -> harmful to the functioning of neurons.

2.

without sufficient levels of GABA -> activation of post-synaptic neurons may get out of control because the excitatory effects of glutamate take over, leading to mental disorders such as anxiety.

3.

imbalance often associated with hyperactivity in various regions of the brain and increased arousal because of sympathetic nervous system activation.

resulting in physiological responses such as increased heart and breathing rates.

4.

When brains neurochemistry is in balance, the inhibitory action of GABA counterbalances the excitatory activity of glutamate and vice versa

Neuromodulator def

Subclass of neurotransmitters -> chemical molecules that alter the overall effectiveness of neural transmission in entire regions of the brain

Through increasing/decreasing responsiveness of many neurons to neurotransmitter signals or action potentials

Physical change of neuromodulators

Increase in dendritic receptors in the post-synaptic neuron (improving post-synaptic stimulation).

Role of Neurotransmitters

To transmit chemical signals to the adjacent neuron

Site of release for Neurotransmitters

Into the synapse

Site of release for Neuromodulators

Outside the synapse into the neural tissue in brain regions

Target of Neurotransmitters

A single post-synaptic neuron

Target of Neuromodulators

Groups of neurons

Speed of action for Neurotransmitters

Moderately fast

Speed of action for Neuromodulators

Moderately slow and last for longer periods

Role of neuromodulator

To alter the neural transmission of neurons by controlling the synthesis and release of neurotransmitters

Dopamine def

a multifunctional neurotransmitter with both excitatory and inhibitory effects that is involved in many CNS functions in addition to pleasure, such as movement, attention, mood, cognition and motivation

Where does the dopamine reward system occur

produced in the ventral tegmental area and travels in neurons to the nucleus accumbens and then the prefrontal cortex

What is the dopamine reward system

The reward pathway refers to a group of structures in the brain that are activated by rewarding or reinforcing stimuli.

How does the dopamine reward system work

when we are exposed to rewarding stimuli, the brain increases the release of dopamine along this reward pathway, which modulates the brain activity of the structures along it.

How is dopamine involved in thirst and drinking

Reward signals are carried by dopamine along the brain's reward pathway -> plays a role in drinking behvaiours/thirst

The gulping motion made by the throat as liquid is swallowed sends a message to the brain that water has been consumed, quieting the neurons that generate the urge to drink.

thirsty mice had a large surge in dopamine levels after drinking water.

however, mice that had water injected directly into the stomach did not release any dopamine afterwards

Implies drinking water as rewarding

How is dopamine involved in addiction

Most addictions are caused by the brain's inability to produce dopamine naturally without the behaviour or the substance that someone is addicted to

What is the anticipation effect in terms of dopamine

Anticipation Effect: Dopamine release is increased during the moments leading up to a potential reward or win, referred to as an anticipation effect.

How is dopamine involved in gambling

Gambling: Losing money when gambling triggers the rewarding release of dopamine almost to the same degree that winning money does. This can set off an urge to keep playing rather than walk away, referred to as 'chasing losses'.

how is dopamine involved in Hunger and Eating

Hunger results from a decrease in the baseline dopamine levels in our brain -> trigger a series of reactions in the brain -> increasing dopamine-dependent behaviours such as seeking out food and eating it.

Cravings: If you have a craving for chocolate, when you eat it, your brain releases more dopamine than if you ate something you were not craving.

Serotonin definiton

Serotonin is an inhibitory neurotransmitter that also acts as a neuromodulator, influencing a variety of brain activities.

How is serotonin involved in the GBA

More than 90% of the body's serotonin is found in the gastrointestinal tract as a part of the gut-brain axis, where it has a role in regulating bowel function and in reducing appetite

Where is the serotonin pathway

Originates in the brainstem and extends to almost all areas of the cerebrum including the cerebral cortex.

How does damage impact the serotonin pathway

Impairments to the serotonin pathway system have been linked to anxiety disorders and depression, as well as Parkinson's disease.

Serotonin role in mood

Balanced serotonin levels often lead to calm, focused, happy and stable moods. When levels dip too low, this has devastating effects because low serotonin levels are most commonly associated with depression and anxiety.

Serotonin role in sleep

Imbalance in serotonin leads to restless sleep during which a person wakes up often, leading them to lack sleep at night and desire sleep during the day.

To sleep, you need to have high sleep pressure. Research generally shows that if the brain lacks serotonin, a person will have a reduced sleep pressure, thus increasing restlessness and wakefulness.

Serotonin role in impulsitivity

A lower level of serotonin in the brain, particularly in the cerebral cortex, leads people to discount a delayed reward, increasing impulsive behaviours.

Serotonin role in aggression

Low levels of serotonin weaken communication between the amygdala and the frontal region of the cerebral cortex, making it more difficult for the frontal area (which makes decisions) to control and regulate emotional responses to anger generated within the amygdala.

Synaptic Plasticity def

Ability for the brains neural structure to be changed by experience

basics for learning and memory

What is LTP

Long lasting strengthening of synaptic connections

Results in more enhanced and effective synaptic transmissions

- Easier activation of post synaptic neurons

Effect of LTP

improve ability of post and presynaptic neurons to communicate at the synapse

Post Synaptic neurons become more responsive as connection strengthens

The more we use information -> more LTP process strengthens pathway -> easier to remember

Advantages of LTP

Increases efficiency in transferring info along pathway

Decreases chance of forgetting learnt info

Structural Changes of LTP

Increase in dendrites - bushing

Increase in receptor sites

Increase in the number of vesicles

Functional Changes of LTP

Increase in neurotransmitters in vesicles

More neurotransmitters are secreted into the synaptic gap from the terminal buttons - shown through increased glutamate

What is LTD

Long lasting decrease in strength of synaptic transmission

Results from lack of stimulation of pre and post synaptic neurons

Post synaptic neuron becomes less responsive to neurotransmitter released by presynaptic neuron

Advantages of LTD

Weakening or elimination of unused synapses -> prunes unnecessary information/connections

If all synapses were strengthened -> new info couldn't be encoded due to limit being reached

Allows us to correct thinking or prior incorrect knowledge

Provides basis of blocking or erasing unwanted thoughts/feelings and behaviours

Structural changes in LTD

Pruning of synaptic connections

Functional changes in LTD

Decrease in neurotransmitter in vesicles

Less neurotransmitters secreted into the synaptic gap

Similarities between LTD and LTP

Both are long lasting and enduring

Both involve glutamate

Both occur at glutamate synapses

Both involve changes in excitability

Both are dependant on activity

Both are critical in learning

Both are observed in brain areas that revolve around learning and memory