Biopsychology Flashcards
What are the two main divisions of The Nervous System?
Central Nervous System
Peripheral Nervous System
What does the CNS consist of?
Brain and Spinal Cord
What are the two main functions of the CNS?
Control of behaviour
Regulation of the body’s physiological processes
How does the CNS carry out its functions?
The brain receives information from the Sensory Receptors (eyes, ears, skin etc.) and sends messages to the muscles and glands using the brain stem to do so
What are the four main areas of the brain?
Cerebrum
Cerebellum
Diencephalon
Brain Stem
What is the Cerebrum?
The largest part of the brain Four lobes: - frontal - temporal - parietal - occipital Two hemispheres
What is the Cerebellum responsible for?
Motor skill
Balance
Coordinating muscles to allow precise movements
What does the Diencephalon contain?
Thalamus
Hypothalamus (regulates body temp, stress response, hunger and thirst)
What does the Brain Stem do?
Regulates breathing and heart rate
Outline the function of the Spinal Cord?
Relay’s information between the Brain and the rest of the body
Allows the brain to monitor and regulate bodily processes and coordinate voluntary movement
Connected to different parts of the body by pairs of spinal nerves which connect to specific muscles/glands
If damaged, body areas connect below the damage will be cut off and stop working
What is the Reflex Arc?
The Spinal Cord contains circuits of nerves that allow simple reflexes without the brain
What does the PNS consist of?
The nervous system throughout the rest of the body
What does the PNS do?
Transmits messages to and from the CNS via neurons
What are the two divisions of the PNS?
Somatic Nervous System
Autonomic Nervous System
Outline the Somatic Nervous System
Connects the senses with the CNS Has sensory and motor pathways Controls skeletal muscles and movement Controlled by the motor cortex Involved in reflex arcs
What are the two divisions of the Autonomic Nervous System?
Sympathetic Nervous System
Parasympathetic Nervous System
Outline the Autonomic Nervous System
Has only motor pathways
Controls organs and glands of the body
Controlled by the Brain Stem
Outline the Sympathetic Nervous System
Activated when stressed
Fight or Flight response: Heart rate and breathing increase Digestion stops Salivation reduces Pupils dilate Flow of blood diverted from surface of the skin
Outline the Parasympathetic Nervous System
Activated when relaxing (conserving energy)
Heart rate and breathing reduce
Digestion starts
Salivation increases
Pupils constrict
What is a neuron?
Specialised cells that move electrical impulses to and from the CNS
What are the parts of a neuron?
Cell body - control centre
Nucleus - contains genetic material
Dendrites - receives electrical impulses from other neurons or sensory receptors
Axon - carries electrical impulse from cell body to axon terminal
Myelin Sheath - insulating layer that protects axon and speeds up electrical impulse transmission
Schwann Cells - make up myelin sheath
Nodes of Ranvier - gaps in myelin sheath which speed up electrical impulse along axon
What are the three types of neuron?
Sensory
Motor
Relay (or Interneurons)
Outline Sensory Neurons
Carry electrical impulses from sensory receptors to the CNS
Convert information from sensory receptors into electrical impulses
When impulses reach the brain they are converted into sensations so the body can react
Some sensory information terminates at the spinal cord, which allows reflexes to occur quickly
Outline Motor Neurons
Located in the CNS, project axons outside CNS
Send electrical impulses from CNS to glands/muscles to affect function
Glands and muscles are Effectors
Outline Relay Neurons
Connect sensory and motor neurons so they can communicate
Mostly found in CNS
Explain the process of Synaptic Transmission
Neurons transmit action potentials, which must cross the synapse, to other neurons
The synapse is the gap between the pre-synaptic and post-synaptic neuron
Vesicles are sacs containing neurotransmitters (which help transfer AP) on the axon terminal of the pre-synaptic neuron
Exocytosis is the process whereby vesicles release their contents as action potential reaches them
The neurotransmitter diffuses across the synapse and binds to specialised receptor sites which are then activated
The effects are terminated via re-uptake
How do psychoactive drugs work?
By increasing or inhibiting the transmission of neurotransmitters across the synapse
What do excitatory neurotransmitters do?
They cause an electrical charge in the membrane of the post-synaptic neuron, resulting in an Excitatory Post Synaptic Potential (EPSP). This means the post-synaptic cell is more likely to fire an impulse.
What do inhibitory neurotransmitters do?
They cause an Inhibitory Post Synaptic Potential (IPSP) which makes it less likely a neuron will fire an impulse.
Define Summation
The net result of the calculation used to determine the likelihood that a cell will fire, which involves adding together the excitatory and inhibitory synaptic input.
What does summation determine?
Whether or not a cell will fire an impulse
More IPSPs means less likely and more EPSPs means more likely
What are the two ways the strength of an EPSP can be increased?
Spatial summation
Temporal summation
In Spatial summation…
A large number of EPSPs are generated at many different synapses, on the same post-synaptic neuron at the same time
In Temporal summation…
A large number of EPSPs are generated at the same synapse by a series of high-frequency action potentials by a pre-synaptic neuron
What is the rate that a cell fires determined by?
What is going on in the synapse:
If more active excitatory synapses, this means a higher rate
If more active inhibitory synapses, this means a lower rate, or possibly no fire at all
What does the Endocrine System provide?
A system of communication in the body using the bloodstream
What do Endocrine Glands do?
Produce and secrete hormones into the bloodstream which are required to regulate many bodily functions
What are the major glands of the Endocrine System?
Pituitary gland
Adrenal glands
What are target cells?
Cells which respond to specific hormones because they have receptors for that hormone.
How is a physiological reaction caused?
When enough receptor sites are stimulated by a hormone.
Where is the pituitary gland located?
Brain
What does the pituitary gland do?
Produces hormones which primarily influence the release of other hormones from other glands.
What is the pituitary gland controlled by?
The hypothalamus, region of the brain just above the pituitary gland.
The hypothalamus…
Receives information about the body’s basic functions and sends a signal to the pituitary gland as a Releasing Hormone.
What do Releasing Hormones cause?
They cause the pituitary gland to send a Stimulating Hormone into the bloodstream and tell the target gland to release its hormone.
What happens as levels of a hormone increase in the bloodstream?
The hypothalamus stops producing releasing hormone and pituitary gland stops secreting stimulating hormone.
What are the two divisions of the pituitary gland?
Anterior
Posterior
What hormone does the Anterior PG release and what is it responsible for?
ACTH, responsible for preparing the body for fight/flight response during stress.
What hormone does the Posterior PG release and what is it responsible for?
Oxytocin, responsible for infant/mother bonding.
Where are the two adrenal glands situated?
On top of the kidneys.
What are the two parts each of the adrenal glands are made up of?
Adrenal Cortex
Adrenal Medulla
What is the Adrenal Cortex?
The outer section of the adrenal gland.
Produces Cortisol
What is Cortisol responsible for?
It is produced in high amounts when stressed.
Responsible for the cardiovascular system.
What is the Adrenal Medulla?
The inner section of the adrenal gland.
Produces Adrenaline and Noradrenaline, needed for fight or flight.
What is adrenaline responsible for?
Increasing heart rate
Dilating pupils
Stopping digestion
What is noradrenaline responsible for?
Constricting blood vessels, which increases blood pressure
What is the Amygdala and what does it do?
It is an area of the brain which associates sensory signals with emotions linked to fight or flight (fear, anger).
When a threat is sensed, the amygdala sends a distress signal to the hypothalamus.
Response to Acute Stress:
Explain the Sympathomedullary Pathway
When SNS is triggered by the hypothalamus, it sends a signal to the adrenal medulla, which releases adrenaline.
Response to Acute Stress:
Adrenaline will…
Increase heart rate
Constrict blood vessels
Increase the rate of blood flow
Raise blood pressure
Divert blood away from the skin, kidneys and digestive system
Increase blood supply to the brain and skeletal muscles
Increase respiration and sweating
This prepares the body for fight or flight by providing energy and rapid response planning resources.
Response to Acute Stress:
What does the Parasympathetic Nervous System do?
Dampens stress response when the threat is gone.
What happens if the brain continues to see something as a threat?
HPA axis kicks in (Hypothalamus, Pituitary Gland, Adrenal Glands)
In response to chronic stress, what does the hypothalamus do?
Releases the chemical messenger CRH (corticotrophin-releasing hormone) into the bloodstream.
In response to chronic stress, what does the pituitary gland do?
The CRH causes it to release ACTH which is transported in the bloodstream to the adrenal glands where its target sites are.
In response to chronic stress, what do the adrenal glands do?
ACTH will cause the adrenal cortex to release cortisol, which can give a quick burst of energy and lower sensitivity to pain, but also impair cognitive performance and immune system.
What happens if cortisol levels get too high?
Hypothalamus and pituitary gland have special receptors to monitor cortisol levels so if they get too high they reduce CRH and ACTH back to normal.
Fight or Flight positive evaluation points:
- From an evolutionary point of view, it makes sense because people would have been able to survive a threat by fighting or fleeing
- People whose adrenal glands malfunction do not have a normal fight or flight response, supporting the idea that adrenaline is essential for the body’s response to stress
Fight or Flight negative evaluation points:
- A psychologist says the first reaction to stress is to freeze (stop, look, listen and be hyper vigilant)
- Females tend and befriend in times of stress because they have oxytocin which means they are likely to stay and protect their offspring
- A psychologist found that males can tend and befriend, e.g. during 9/11 both males and females showed this
Define localisation of function
The idea that specific functions have specific locations in the brain
Where is the Visual Cortex located?
The Occipital lobe and spans both hemispheres
Where is the Auditory Cortex located and what does it do?
The temporal lobe and spans both hemispheres
Contains several areas which process different visual info
Explain visual processing
Processing begins in the retina
Light enters and strikes photoreceptors and nerve impulses are transmitted via the optic nerve, from the retina to the brain.
Most stop in the thalamus, which acts as a relay station and passes the info to the visual cortex
Outline the auditory pathway
It begins in the cochlea (in the inner ear). Here, sound waves are converted to nerve impulses which travel to the auditory cortex via the auditory nerve.
The brain stem then decodes, it goes to the thalamus for further processing and is then relayed to the auditory cortex