biopsychology

start from page 11 - norepinephrine

neuron

a nerve cell that sends messages throughout the body, the basic cell of the nervous system

dendrites

receptor sites that receive incoming info from the chemical neurotransmitters

receptor site

where neurotransmitters bond, works like a lock and key (only certain neurotransmitters can fit in certain receptor sites)

dendritic trees

more than one set of dendrites 

soma (cell body)

the core section of the neuron that contains genetic information, maintains the neuron’s structure and provides energy to drive activities

nucleus

the control center of the cell in the soma which controls the cell’s activities and contains its genetic material

myelin sheaths 

fatty substance that acts as an insulating layer around the axon. allows electrical impulses to transmit quickly and effectively throughout the nerve cell. exists to keep the message intact and travel quickly, so, if damaged impulses slow down 

myelinated neurons are mostly in the NS 

axon

a long tail-like structure that carries nerve impulses away from the cell body to the axon terminals

length can vary depending on where it is (some go from spinal cord to toe)

axon terminals

end of the neuron where it reaches out to make connections and transmit messages to other neurons at the synapse

convert electrical signals (in neuron) to chemical signals (neurotransmitters)

terminal buttons or terminal sacs

small knobs at the end of axon terminals that hold and release neurotransmitters

synapse (synaptic cleft)

the space between each neuron where they connect and communicate w each other 

how a neuron fires (just list 1-6)

1. resting potential

2. threshold

3. action potential/neural impulse/ impulse

4. release

5. refractory period

6. reuptake (sometimes)

hnf - resting potential

it is ready to receive the signal, but is at rest

it is polarised w a neg charge compared to the pos charge outside the cell

membrane is semi-permeable

hnf - threshold 

reaches this point when enough neurotransmitters bond to dendrites

in this stage, the neuron will fire (all or nothing) 

membrane is now permeable (interactions between + and - ions) 

all or none law - hnf

once the stimulus threshold is met, the neuron fires

hnf - action potential/neural impulse/ impulse

an ELECTRICAL signal is sent down the axon where there is a collision of pos & neg ions, and its loses its neg charge (depolarisation)

neurons always fire at full strength so the signal doesn’t weaken as it travels

hnf - release 

terminal buttons release neurotransmitters in the synapse. CHEMICAL LANGUAGE. 

these release neurotransmitters bind to the receptor sites of the next cell 

hnf - refractory period

very brief period (fraction of a millisecond) where the neuron can’t fire

it repolarises and returns to resting potential gradually

hnf - reuptake (sometimes)

when the 1st neuron reabsorbs unused neurotransmitters

they’re recycles and reused in the next cycle

neurotransmitters 

chemical messengers; they carry messages from one neuron to another cell (nerve. muscle, gland cell) 

makes sure the body functions normally 

acetylcholine (ACh)

an excitatory neurotransmitter that enables voluntary muscle movement, aids in memory production (hippocampus) and learning

ACh - associated conditions

alzheimer’s disease - linked w low levels of ACh

memory erodes, muscles weaken, decline in thinking, learning and organising

usually affects people 65 or older

dopamine 

involved in muscle movement, pleasurable reward and motivation, behaviour, cognition, attention, sleep, arousal, mood, learning and impulse control 

“feel good hormone” - gives you a sense of pleasure and motivation, humans actively seek doing things that release dopamine (reward system) 

dopamine - associated conditions

parkinson’s disease - linked to low dopamine; an age-related degenerative brain condition that causes parts of the brain to deteriorate. causes slowed movements, tremors, depression, decreased mobility, gut problems, mild cognitive problems, etc. 

schizophrenia - linked to excess dopamine; characterised by erratic behaviours, hallucinations, delusions, disconnection from reality, etc. 

serotonin 

influences mood by acting as the body’s natural “feel-good chemical”; digestion (90% of serotonin found in gastrointestinal tract), hunger, sleep (quality) & arousal 

can raise levels by exercising or eating foods that contain it 

serotonin - associated conditions

depression and other mood and anxiety disorders are linked to low serotonin levels

endorphins

acts as a natural pain-reliever that’s made in the pituitary gland and hypothalamus

released when the body feels pain or stress to temporarily turn off the body’s feeling of pain

also released during pleasurable activities (ex: runner’s high)

endorphins - associated conditions 

low release can cause depression, body aches, addiction, sleep issues

norepinephrine

excitatory neurotransmitter that acts as the brain’s version of adrenaline to increase alertness, arousal and attention

is released during fight-or-flight and causes adrenaline to release

norepinephrine - associated conditions

low levels can be related to depressed mood, anxiety disorders, etc.

high levels are associated w bipolar disorders

GABA 

main inhibitory neurotransmitter that lessens a nerve cell’s ability to receive or send messages 

slows down brain function & has a calming effect to control nerve cell hyperactivity 

reduces stress & anxiety 

improves sleep 

GABA - associated condition

undersupply is linked to seizures, tremors, insomnia, anxiety and mood disorders

glutamate

the most abundant excitatory neurotransmitter (makes more likely a message will travel)

affects learning and memory bc it spreads info quickly

activity is high when awake and in REM sleep

also called MSG (monosodium glutamate) in food

glutamate - associated conditions 

oversupply can overstimulate the brain, producing migraines or seizures 

can damage the brain if optimal conditions deviate too much 

endocrine system

the body’s glands and organs that release hormones into the bloodstream

pituitary gland

“master gland” of the endocrine system that releases many hormones into the bloodstream

is a pea-sized gland at base of brain below hypothalamus

regulates growth and controls other endocrine glands

controlled by the hypothalamus

releases growth hormones

also apart of the forebrain

adrenal glands 

small triangle-shaped glands on top of each of 2 kidneys 

released hormones to manage bodily processes like metabolism, blood pressure, stress response, etc. 

releases adrenaline 

hormones

chemical messengers produced by the endocrine system that travel through the bloodstream to affect bodily functions

adrenaline (epinephrine)

released by adrenal glands in response to stress - causes fight-or-flight response as part of the sympathetic NS

allows the body to metabolise energy sources faster

• causes “cold sweat” - where you’re sweating when you’re not hot or physically active bc you perceive smth as stressful

oxytocin

connected to love and social bonding

released during childbirth to stimulate contractions, lactation and promote pair bondings betw. mom & baby

promotes group cohesion and social trust 

made by hypothalamus but posterior pituitary gland stores and releases it 

females have higher levels than males 

more than 20s of skin-to-skin contact can increase levels 

positive feedback loop (releasing causes more to be released and produced) 

causes “tend and befriend response” - helping others first in stressful situations 

melatonin

plays a role in managing sleeping and waking cycles (Circadian rhythm - 24hr cycle); body temp; overall mood

more of this makes u drowsy & helps u fall asleep

hypothalamus tracks daylight & regulates the release of melatonin

can be related to sleep disorders

the nervous system

body’s control center made of the CNS & peripheral NS f

Central Nervous System (CNS) 

brain + spinal cord 

takes in info from sensory nerves to process & respond to the, 

3 main functions of the CNS

receive sensory info

process info it receives (integration)

respond w/ motor output

CNS - brain

regulates thoughts, feelings & mvmts

brain sends messages to spinal cord that sends messages to nerves (peripheral NS) to complete an action

signals are constantly travelling to keep the body functioning

interneurons 

neurons found exclusively in the CNS that act as the “middle man” between sensory neurons and motor neurons; sends messages within CNS 

CNS - spinal cord

column of nerves (bundle of axons) that come together encased in bone found in the vertebral column

CNS - spinal cord function

send motor commands from the brain to the peripheral body & relay info from the sensory organs to the brain 

CNS - spinal cord - reflex

ability to direct behaviours in a limited but very specific way called a reflex

a basic involuntary response-innate-that is designed to protect the individual that doesn’t require the brain to interpret it

peripheral nervous system (peripheral NS)

rest of the NS outside of the CNS

key role in sending info from diff areas of the body back to the brain

carries out commands from the brain to various parts of the body

peripheral NS - 3 main functions

sense the environment/ body (somatic)

movement (somatic)

unconscious processes (autonomic)

sensory neurons

nerve cells that are responsible for detecting & transmitting sensory info from the env to the body or body to CNS for processing

important to how we respond to outside stimuli & our senses

motor neurons 

nerve cells that carry messages FROM CNS to muscles & glands 

enables mvmt and other motor functions 

somatic nervous system

“skeletal nervous system”

all of the muscles connected to bone

in charge of voluntary mvmt

motor neurons travel via the somatic NS to stimulate skeletal muscles leading to contractions & mvmts

uses sensory neurons to relay info (touch, temp, pain) to CNS & involved in reflexes

autonomic nervous system

regulates involuntary physiological processes

ex: heart rate, digestion, breathing

governs the “vegetative state” where internal bodily processes still function normally but somatic processes do not

biofeedback

trying to exert control over smth that is automatic 

Sympathetic Nervous System

Involved in the flight-or-fight response

Stress

Uses adrenaline, norepinephrine and endorphins

Flight or fight response

Automatic physiological response that activates in times of stressful or threatening situations to prepare the body for physical actions either fighting off danger or fleeing

Physical response from fight or flight

Dilates pupils

Blood and oxygen are redirected to leg and arm muscles

Heart rate and blood sugar increase

Energy sources are metabolised faster to provide energy surge

Airways open up for more oxygen

Inhibits digestion

Endorphins make you sweat and not feel pain

Possible urination or defecation in extreme cases

Parasympathetic nervous system

Responsible for calming the body down and conserving energy after a stressful situation

Return to homeostasis

Promotes relaxation of bodily functions

Slows heart rate and metabolism

Constricts pupils

Stimulates digestion

Tend or befriend response

Response to stressful situations where u think of other people’s safety before your own

You form a bond & make connections

Opponent response

Parasympathetic NS counteracts the effects of the Sympathetic NS

Both in the autonomic NS in peripheral NS but work in opposition

Brain

Hindbrain structure

Most primitive of the 3 major regions of the brain

Located on the posterior (back) of the brain

Plays a crucial role in regulating basic life functions like heart rate, breathing, balance and coordination

Contains the brain stem (pons and medulla) and cerebellum

Cerebellum

Located at the back of the brain extending from the rear of the brainstem beneath the cerebral cortex

Crucial for coordinating voluntary movements by fine tuning motor control, balance & posture, motor learning, timing & precision

Stores implicit memories

Called “little brain” bc of its size & appearance

Medulla

Connects the brain and spinal cord (base of brain, top of spinal cord) and surrounds the spinal cord

Involved in regulating essential autonomic functions like heart rate, breathing & reflexes

Pons

Located above the medulla in front of the cerebellum and serves as a bridge between different parts of the brain

Involved in sleep, arousal, relaying info, breathing (secondary)

Midbrain structure

Smallest part of the brainstem

Huge role in alertness

Above hindbrain & below forebrain

Bridge between them

Reticular Activating System/ Reticular Formation (RAS)

A network that spans from the brainstem to the midbrain

Critical for sustaining consciousness, sensory processing and attention

Damage to the RAS can induce coma/vegetative state/ sleep disorders

Forebrain structure (cerebrum)

Most complex & large (takes up 70%)

Allows for complex behaviour and thinking processes

Made of the limbic system, corpus callosum & cerebral cortex

Limbic system

Complex set of structures involved in emotion, memory & motivation

Located in the inner edges of the cerebral cortex

Plays an essential role in regulating emotional responses

Contains the amygdala, hippocampus, hypothalamus and thalamus

Amygdala

Small almond shapes cluster of neurons deep within the temporal lobe above the brainstem

Essential for processing and modulating extreme emotions

“Panic button” of flight or fight response

Hippocampus

Small curved structure in the medial temporal lobe above

Memory formation/storage (converts STM to LTM during sleep) & spatial navigation

Holds declarative/ explicit memories

Left hippocampus

Holds semantic memories (language, learning, logic, linguistics, general knowledge)

Holds episodic memories (events, episodes of your life-personal memories). The analytic part of the brain that deals w facts, events & explicit info (remembers phone #s, stories)

Right hippocampus

More visual side that helps w colour, shapes, creativity spacial memory (locations, physical spaces, ect. w/ mental map) by integrating memory info w/ senses; and performing tasks of visual or spatial nature(dancing, drawing, ect.)

Hypothalamus

• small structure below the thalamus that plays a crucial role in maintaining homeostasis and regulating physiological functions(hunger, thirst; body temp; sex; aggression) acting as the major link between the endocrine system and the Nervous System(controls release of hormones in pituitary gland).

• regulates emotional and behavioral responses

• Damage can lead to disruptions of homeostasis, sleep disorders, endocrine disorders, obesity or starvation, emotional dysregulation or sexual dysfunction 

thalamus

• Sits on top of the brainstem above the RAS as the brain’s “relay station” the processes and relays sensory info to the cerebral cortex; essentially acts as the gatekeeper of sensory signals(except olfactory) to be involved w/ perception, movement and cognition. Blocks sensory input during sleep(regulate sleep w/ RAS)

• Damage can lead to sensory deficits, emotional disorders, sleep disorders