biological influences section - study :) Flashcards
Define the Central Nervous System
Consists of the brain and the spinal cord and is responsible for how we think, feel and perceive the world around us. It also enables us to make decisions, solve problems, have emotions etc.
Define the brain
Receives, integrates and processes information from the rest of the body, and generates a response to it
(RIP)
Define the spinal cord
Connects the brain to the rest of the body via its connection to the peripheral nervous system
Define the hindbrain
location - base of the brain at the back of the skull.
Consists of - the pons, medulla and cerebellum
Function - controls our basic survival functions (heart rate, breathing), co-ordinating voluntary movement and reflex actions (coughing, swallowing, vomiting)
Define the midbrain
Location - between the hindbrain and forebrain
Consists of - reticular formation
Function - keeps us alert, awake and vigilant (posture, movement, consciousness, sleep-wake cycle)
Define the forebrain
Location - top of the brain, above the midbrain
Consists of - hypothalamus, thalamus, cerebrum
Function - controls higher brain functions and processes (emotions, sensations, perceptions, reasoning)
Describe the types of matter in the spinal cord
Grey matter = made up of cell bodies, their axons and their dendrites
- centre of the spinal cord
White matter = columns of myelin coated axons (known as tracts)
- run of the outer layers of the spinal cord
What are the two types of tracts in white matter
ascending tracts and descending tracts
- involved in the transmission of information up and down the spine (highway)
sensory/afferent neurons - transmit information towards the CNS
motor/efferent neurons - transmit information away from the CNS
(SAME)
Describe the spinal cord’s process
the axon columns (tracts) are bundled together into spinal nerves that branch off between gaps in the vertebrate, going into the arms, legs and torso.
these spinal nerves carry the messages to and from the spinal cord, connecting it to the brain and the PNS.
Sensory neurons - enter the dorsal (back) side of the 31 spinal cord segments (the top)
Motor neurons - exit the ventral (abdominal) side of the 31 segments (the bottom)
Define the Peripheral Nervous System
All of the nerves outside of the CNS (brain and spinal cord), including the spinal nerves (connected to muscles, organs and glands) and cranial nerves (connected to the lobes of the brain)
Main function:
- transmit sensory information from the body’s internal and external environments to the CNS,
- transmit motor commands from the CNS to the rest of the body
Define the somatic nervous system
a subdivision of the peripheral nervous system, function - senses external stimuli (light, sound, touch) and controls a voluntary response, process - sensory neurons receive sensory info from receptor cells (skin, joints, eyes) and transmits the info to the CNS (experience heat, etc.) Motor neurons receive commands from the CNS, which is transmitted to the appropriate skeletal muscle to enable voluntary movement
(voluntary, involves the brain)
Define the autonomic nervous system
a subdivision of the PNS
function - controls the activity levels of our internal organs / glands, which are responsible for survival
process - transmits motor commands from the brain to the ‘smooth muscles’ (heart, pupils) to regulate activity levels (pump more adrenaline, etc.)
(involuntary, independent from the brain)
- has 2 subdivisions: sympathetic, parasympathetic
Define the sympathetic nervous system
A subdivision of the autonomic nervous system which causes an arousing effect. function - dominates when we experience heightened emotions, or during vigorous physical activity (also when flight/fight response is activated) e.g. jump scare in horror movie
(automatic - no voluntary control)
Define the parasympathetic nervous system
A subdivision of the autonomic NS, which causes a calming effect.
Function - maintains a level of homeostasis (keeps internal systems at a balanced, healthy state by maintaining vital functions - e.g. heart rate, blood pressure)
(automatic - no voluntary control)
Outline what the Sympathetic NS does for a scenario
= it uses the body’s internal resources to provide extra energy that is required for increased physical activity or to deal with intense emotions (e.g. fear) or stressful/threatening situations
- Sensory / afferent neurons receive the sensory information from receptor cells of the perceived threat (hearing footsteps behind you, seeing the clown), which is transmitted to the CNS via the spinal cord.
- The brain receives, integrates and processes the information, and the sympathetic nervous system is automatically activated to prepare our body for emergency action (flight or fight response)
- The brain transmits motor / efferent neurons to the PNS to carry out the following actions: …
Outline symptoms of a sympathetic response
adrenaline levels increase
- increased heart rate = increased response time
increased heart rate and blood pressure
= carry more oxygen to the body
increased respiration rate
= quicker reaction time
Increased muscle tension
= quicker reaction time
Dilated pupils
- more visual information
Inhibited digestion and saliva
Relaxed bladder
Outline symptoms of a parasympathetic response
Decreased hormone activity
Decreased heart rate to normal function
Respiration rate returns to normal
Relaxed muscles
Constricts pupils
Stimulates digestion and salivation
Contracts bladder
Define stress
= A state of intense arousal, caused by our internal organs operating at abnormally high levels – when the sympathetic nervous system is still active long after the perceived threat is gone
- Being stressed for a long time can be dangerous, as we can develop physiological / psychological disorders – can lead to a breakdown
Define spinal reflex arc
An automatic response to ‘emergency’ sensory stimuli, through interneurons instead of the brain.
Describe the process of the spinal reflex arc
- Pain receptors are stimulated (e.g. in skin, when touching an iron)
- This triggers an impulse (action potential) which passes along the sensory neuron, to the dorsal root of the spinal cord
- Instead of going to the brain, the impulse passes through an interneuron located in the spinal cord
- The interneuron sends a motor command (exiting through the ventral root of the spinal cord), causing muscles to contract from the painful stimuli
- The brain then receives and processes the impulse, after the reaction has happened
Define neural transmission
the function of a neuron to transmit messages within the nervous system.
Define neuron
a type of cell specialised to receive, transmit and process information.
Define neurotransmitters
chemicals which enable activity across the synaptic gap between neurons.
Define a synapse
a small gap between neurons, where neural impulses are transmitted via neurotransmitters
Describe the process of neurotransmission
1 – the dendrite receives a message and transmits the message down the axon via the action potential (an electrical impulse)
2 – this stimulates the release of neurotransmitters from the axon terminal into the synaptic gap
3 – the neurotransmitters cross the synaptic gap and are absorbed by the receptor sites on the dendrites of the post-synaptic neuron (receiving neuron)
4 – this triggers a new action potential, and the process begins again.
5 – any excess neurotransmitters left in the synaptic gap are re-absorbed by the pre-synaptic neuron (sending neuron) through a process called RE-UPATKE.
Describe the lock and key model
Receptor sites = tiny areas on the cell membrane which are sensitive to certain neurotransmitters.
Both receptor sites and neurotransmitters have a specific shape
Only if the neurotransmitter and the receptor site are sensitive (fit) to each other, like a lock and key, they will be successful in altering neural activity
Describe excitatory and inhibitory
Neurotransmitters may act in 1 of 2 ways when they arrive at the post-synaptic neuron.
1 – Excitatory effect
- They make it more likely for the post-synaptic neuron to fire an action potential.
2 – Inhibitory effect
- They make it less likely for the post-synaptic neuron to fire and pass on the neural impulse (they inhibit/block the neuron’s activity levels)
What is an excitatory neurotransmitter
- Speeds up neural activity and increase the likelihood that an action potential is sent.
- Regulate many bodily functions (e.g. thought processes, flight/fight response, motor movement) and act as the body’s natural stimulants (promotes awareness, energy and activity)
o Dopamine, norepinephrine
What is an inhibitory neurotransmitter
- Slows down the neural activity and decreases the likelihood that excitatory signals are sent.
- Acts as the body’s natural tranquilisers (promotes sleep, calmness and decreases aggression)
o Serotonin
What are the main functions of serotonin - including excess and deficiency causes
functions -
Sleep-wake cycle, mood regulation, hunger and appetite
excess -
schizophrenia, mania, sedation/increased sleep
deficiency -
depression, anxiety disorders, insomnia
What are the main functions of dopamine - including excess and deficiency causes
functions -
Voluntary movement, Learning and memory, Alertness and attention, Emotion and motivation/drive, Pleasure and reward-seeking
excess -
schizophrenia, addiction, tourettes syndrome
deficiency -
Parkinson’s, depression, ADD/ADHD
What are the main functions of neuradrenaline - including excess and deficiency causes
function - flight/fight response, alertness, arousal and attention
excess -
stress, anxiety disorders
deficiency -
depression
How does dopamine cause Parkinson’s disease
Parkinson’s = a progressively degenerative neurological disorder which affects the control of body movements.
- one of dopamine’s functions is voluntary movement
What are the 4 lobes
frontal lobe,
parietal lobe,
occipital lobe,
temporal lobe
Describe the frontal lobe
Cortex/area - Primary motor cortex and Broca’s area
Function -
- Associated with thinking, feeling, decision making and behaviour,
- Generates neural impulses that travel down the spinal cord, to control voluntary movement through the control of skeletal muscles,
- Coordinates numerous functions of the other lobes and determines behavioural response.
Damage -
Change in behaviour, thinking, processing and speech.
Broca’s aphasia
Describe the parietal lobe
cortex - primary association cortex
functions -
enables us to read, write, solve mathematical problems,
responsible for bodily sensations (touch, pain, temp),
processes these bodily sensations,
spatial awareness and some aspects of speech
damage -
right hemisphere = loss of imagery, visualisation of spatial relationships, neglect of left-side of body
left hemisphere = problems in maths, reading and writing
Describe the occipital lobe
primary visual cortex
functions -
Visual functions of the eyes, in order to produce quick responses to the visual environment (receives visual info from the retina and interprets it)
damage -
numerous visual problems (full or partial blindness)
Describe the temporal lobe
primary auditory cortex, Wernicke’s area
functions - auditory perception (hearing), speech production and memory, receives info from the ears and interprets the info
damage -
Wernicke’s aphasia
What is aphasia
a language disorder apparent in speech (comprehension or production), writing or reading
caused by damage to the areas associated with these functions (commonly by strokes - lack of blood supply)
Describe Broca’s aphasia
- also called non-fluent aphasia
Caused by damage to the Broca’s area, located in the left frontal lobe next to motor cortex areas that control muscles involved in speech.
Causes the affected individual to have difficulty speaking, although their comprehension of speech remains unaffected.
A person with Broca’s aphasia would talk with very short sentences, using mainly nouns and verbs (no ‘the’ or ‘to’ etc.)
Describe Wernicke’s aphasia
- Also called fluent aphasia
Caused by damage to the Wernicke’s area, located in the temporal lobe of the left hemisphere.
A person with Wernicke’s aphasia will often have fluent and grammatically correct speech, but what is said is nonsense.
- Difficulty comprehending speech and talking in a meaningful way
Define heredity and state its role
= the passing on of traits from parents to offspring
role -
the genes that we inherit from our parents guide how we develop physically,
e.g. regulate the production of pigment of in our bodies (resulting in blue / brown eyes etc.)
Define environment and state its role
= all of the external physical, biological, social and cultural conditions that influences an individual’s functions.
role
- Heredity sets limits on how individuals can ‘turn out’, but the environment determines how the individual will turn out within those limits.
e. g. a child could inherit genes that would enable him to be tall, but if he has inadequate nutrition for a long period of his early life, then he may not become tall.
Define epigenetics
the study of the transmission of information from one generation to the next through genetic inheritance that affects the traits of the offspring without alteration of the DNA or alteration that occurs from environmental factors.
Outline the rat study associated with heredity
Background:
- a male rat was exposed to the chemical acetophenone and received a painful electric shock at the same time
- the rate learnt to fear the smell (through classical conditioning/association)
- extra neurons sprouted in the rat’s nose, making him sensitive to the smell
Findings:
- the rat’s pups and pup’s pups were also sensitive to the smell, despite never meeting the original male and never smelling the scene before
- they also had the extra neurons in their nose
- The rat’s DNA wasn’t altered
= certain epigenetic tags are switched on and off (such as in the male’s sperm cells, however the location of other tags are unknown).
Outline the famine study associated with heredity
In Sweden, boys who suffered winter famines went on to have extremely healthy sons and their sons too (low heart rate and diabetes risk, etc.)
E.g. they lived 32 years longer on average compared to the grandsons of boys who hadn’t endured the famine
Define hormones and state 4 types
Chemical messengers produced by endocrine glands, which pass through the bloodstream and affect other parts of the body.
1 - adrenal glands
2 - thyroid glands
3 - pituitary glands
4- menopause
Define adrenal glands
= Triggers the ‘flight or fight’ response to deal with emergency situations (causing reactions like increased heart and respiratory rate, muscle contraction and dilated pupils)
types of adrenal hormones include:
- adrenaline (produced in adrenal glands, act mainly as a hormone, responsible for flight/fight response)
- noradrenaline (produced in the sympathetic nervous system, functions mainly as a neurotransmitter at the synapse of the sympathetic nervous system)
Define pituitary glands
- Triggers the release of hormones from all the other glands
- Produces a growth hormone that stimulates the growth and development of body cells
- Plays a role in the changes that occur during puberty (the time of sexual maturation) - e.g. stimulates woman’s ovaries to produce more oestrogen etc.
Define thyroid glands
- Produces the hormone thyroxin (necessary for the development of the brain and N.S.)
- Early deficiency – intellectual deficiency
- Late deficiency – the individual will grow more slowly
Define menopause
- Occurs on in women, typically at during late 40s / early 50s
- Menstrual periods completely stop
- Dramatic decline in the production of oestrogen by the ovaries
- Often accompanied by uncomfortable symptoms (hot flushes and fatigue), sometimes depression and irritability
Define stimulants
A type of substance which excites the N.S. and arouses bodily functions
physiological effects -
- increased heart rate, excites the CNS, suppressed appetite
psychological effects -
- arousal, increased confidence
examples -
- caffeine, methanthetamine
Define depressants
A type of substance which calms the N.S. and slows bodily functions
physiological effects
- decreased heart rate, loss of control over bodily movements, slowed down CNS
psychological effects
- reduced inhibitions (self-consciousness), memory loss
examples
- alcohol, marijuana
Define hallucinogens
A type of drug which changes our perception and gives us sensory images without input from the senses themselves
physiological effects
- increased heart rate and blood pressure, clammy hands
psychological effects
- reduced inhibitions, altered perceptions, euphoria
examples
- LSD, magic mushrooms
Define interneurons
Interneurons act as the connecting neuron between the sensory and motor neurons.
Located in the spinal cord and the brain
Outline what is required for a scenario question regarding ‘swatting away a fly’
INCLUDE:
- The CNS is made up of the brain and spinal cord
- The PNS is made up of the autonomic and somatic nervous system
- The somatic nervous system deals with the skeletal muscles (voluntary)
- Receptor sites receive information and transmits it to the sensory neuron
- The brain receives, integrates and transmits the information
- Sends a message down via the motor neuron to the muscles and rest of the body
- So that he could swat the fly away (by the muscle contraction)
