Summary
Summary AQA A-Level Psychology Knowledge Organiser Biospychology
- Course
- Institution
Full Knowledge Organiser for AQA A-Level Psychology Biopsychology
[Show more]
Seller
Follow
kjakhu05
Reviews received
Content preview
DIVISIONS OF THE NERVOUS SYSTEM:• the human nervous system is divided into the central nervous system and peripheral nervous system, with each
of these further divided in different components, each with a different function but all working together
• Central Nervous System (CNS) = comprises the brain and the spinal cord, it receives information from the sense and -
------------------------------------------- controls the body’s responses
• Peripheral Nervous System = the part of the nervous system that is outside the brain and the spinal cord THE PERIPHERAL NERVOUS SYSTEM:
o all the nerves outside the CNS make up the peripheral nervous system
• Autonomic Nervous System (ANS) = governs the brain’s involuntary activities and is self-regulating
o this function of this part of the nervous system is to relay nerve impulses from the CNS to the rest of the body
→ is divided into the sympathetic branch (fight-or-flight) and parasympathetic branch (rest and digest)
and from the body back to the CNS
• Somatic Nervous System = the part of the peripheral nervous system responsible for carrying sensory and motor ----- o there are two main divisions of the peripheral nervous system:
------------------------------------ information to and from the central nervous system → the somatic nervous system
• Brain = part of the CNS responsible for coordinating sensation, intellectual, and nervous system → the autonomic nervous system
• Spinal Cord = bundle of nerve fibres enclosed within the spinal column, connects nearly all parts of body with brain
THE SOMATIC NERVOUS SYSTEM:
THE CENTRAL NERVOUS SYSTEM: • the somatic nervous system is made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves
o the CNS has two main functions: control of behaviour and regulation of the body’s physiological processes → Cranial Nerves = nerves that emerge directly from the underside of the brain
o in order to do this, the brain must be able to receive information from the sensory receptors and be able to → Spinal Nerves = nerves that emerge from the spinal cord
send messages to the muscles and glands of the body – this involves the spinal cord
• these nerves have both sensory neurons and motor neurons
THE SPINAL CORD: → Sensory Neurons = relay messages to the CNS
• the main function of the spinal cord is to relay information between the brain and the rest of the body → Motor Neurons = relay information from the CNS to other areas of the body
→ this allows the brain to monitor and regulate bodily processes and to coordinate voluntary movements • is also involved in reflex actions without the involvement of the CNS, which allows the reflex to occur very quickly
• spinal cord is connected to different parts of the body by spinal nerves, which connect to specific muscles and glands
• the spinal cord also contains circuits of nerve cells that enable us to perform some simple reflexes without the THE AUTONOMIC NERVOUS SYSTEM:
direct involvement of the brain, for example pulling tour hand away from something that is hot • the body carries out some actions without your conscious awareness, e.g. heart beat and digestion
→ if the spinal cord is damaged, areas supplied by spinal nerves below the damaged site will be cut off from the → involuntary actions such as these are regulated by the ANS
brain and will stop functioning → this system is necessary because vital bodily functions such as heartbeat and digestion would not work so
efficiently if you had to think about them
THE BRAIN:
The brain can be divided into four main areas: the cerebrum, cerebellum, diencephalon, and brain stem • the ANS has two parts: the sympathetic and the parasympathetic
→ both of these divisions tend to regulate the same organs but have opposite effects
• Cerebrum = largest part, further divided in 4 different lobes, each of which has a different primary function
→ this is because of the neurotransmitters associated with each division
→ the cerebrum is split down the middle into two halves called cerebral hemispheres
→ generally, the sympathetic division uses the neurotransmitter noradrenaline, which has stimulating effects, and
→ each hemisphere is specialised for particular behaviours, and the two halves communicate with each other
the parasympathetic division uses acetylcholine, which has inhibiting effects
through the corpus callosum
• Cerebellum = it is involved in controlling a person’s motor skills and balance, coordinating the muscles to allow ----- • Sympathetic Nervous System: primarily involved in responses that help us to deal with emergencies, such as --------
--------------------precise movements sits beneath the back of the cerebrum ---------------------------------increasing heart rate and blood pressure and dilating blood vessels in muscles
→ abnormalities can result in a number of problems, including speech and motor problems and epilepsy → neurons from the SNS travel to virtually every organ and gland within the body, preparing the body for the
rapid action necessary when the individual is under threat
• Diencephalon = lies beneath the cerebrum and on top of the brain stem → for example, the SNS causes the body to release stored energy, pupils to dilate and hair to stand on end
→ within this area are two important structures, the thalamus, and the hypothalamus → it slows bodily processes that are less important in emergencies, such as digestion and urination
• Thalamus = acts as a relay stations for nerve impulses coming from the sense, routing them to the appropriate part • Parasympathetic Nervous System: relaxes people once the emergency has passed
--------------- of the brain where they can be processed → whereas the SNS causes the heart to beat faster and blood pressure to increase, the PNS slows the heartbeat
• Hypothalamus = has a number of important functions, including body temperature regulation, hunger, thirst down and reduces blood pressure
→ also acts as link between endocrine and nervous system, controlling release of hormones from pituitary gland → another benefit is that digestion (inhibited when the SNS is aroused) begins again under PNS influence
• Brain Stem = responsible for regulating the automatic functions that are essential for life (inc. breathing, heartbeat) → because the PNS is involved with energy conservation and digestion, it is sometimes referred to as the body’s
→ motor and sensory neurons travel through brain stem, allowing impulses to pass between brain and spinal cord rest and digest system
,THE STRUCTURE AND FUNCTION OF NEURONS: SYNAPTIC TRANSMISSION:
Synaptic Transmission = refers to the process by which a nerve impulse passes across the synaptic cleft from one -------
Neurons = cells specialised to carry neural information throughout the body ---------------------------------neuron (the presynaptic neuron) to another (the postsynaptic neuron)
→ neurons can be one of three types: sensory neurons, relay neurons, or motor neurons
→ neurons typically consist of a cell body, dendrites, and an axon • synaptic transmission is the process by which one neuron communicates with another
• information is passed down the axon of the neuron as an electrical impulse known as action potential
• dendrites at one end of the neuron receive signals from other neurons or from sensory receptors • once the action potential reaches the end of the axon it needs to be transferred to another neuron
→ dendrites are connected to the cell body, the control centre of the neuron • it must cross over the synaptic gap between the presynaptic neuron and post-synaptic neuron
• at the end of the neuron (in the axon terminal) are the synaptic vesicles, which contain chemical messengers,
• from the cell body, the impulse is carried along the axon, where it terminates at the axon terminal known as neurotransmitters
• in many nerves there is an insulating layer that forms around the axon – the myelin sheath • when the electrical impulse (action potential) reaches these synaptic vesicles, they release their contents of
→ this allows nerve impulses to transmit more rapidly along the axon neurotransmitters
→ if the myelin sheath is damaged, impulses slow down • neurotransmitters then carry the signal across the synaptic gap
• they bind to receptor sites on the post-synaptic cell, completing the process of synaptic transmission
• the length of a neuron can vary from a few millimetres up to one metre
→ excitatory neurotransmitters (e.g. adrenaline) make the post synaptic cell more likely to fire
→ inhibitory neurotransmitters (e.g. serotonin) make them less likely to fire
Sensory Neurons = carry nerve impulses from sensory receptors to the spinal cord and the brain
• are found in various locations in the body → summation is the net effect of the EPSPs and IPSPs (adding up the positive and negative charges)
• they convert information from these sensory receptors into neural impulses
EXCITATORY AND INHIBITORY NEUROTRANSMITTERS:
• when these impulses reach the brain, they are translated into sensations of, for example, visual input, heat, pain,
etc, so that the organism can react appropriately Neurotransmitter = chemical substances that play an important part in the nervous system by transmitting nerve -------
• not all sensory information travels as far as the brain, some neurons terminate in the spinal cord ---------------------------impulses across a synapse
• this allows reflex action to occur quickly without the delay of sending impulses to the brain → neurotransmitters can be classified as either excitatory or inhibitory in their action
• Excitatory Neurotransmitters = increase the likelihood an excitatory signal is sent to the postsynaptic cell, which is --
Relay Neurons = these neurons are the most common type of neuron in the CNS, they allow sensory and ------------------
----------------------------------------- then more likely to fire – e.g. adrenaline
---- motor neurons to communicate with each other
• Inhibitory Neurotransmitters = generally responsible for calming the mind and body, inducing sleep, and filtering ---
• most neurons are neither sensory or motor, but lie between sensory input and motor output
------------------------------------------out unnecessary excitatory signals – e.g. serotonin
• relay neurons allow sensory and motor neurons to communicate with each other
• these relay neurons lie wholly within the brain and spinal cord Binding with a Postsynaptic Receptor:
• Excitatory: causes electrical change in the membrane of the cell, resulting in an excitatory post---------------------
Motor Neurons = form synapses with muscles and control their contractions synaptic potential (EPSP), meaning postsynaptic cell is more likely to fire
• refers to neurons which conduct signals from the CNS to effector organs such as muscles • Inhibitory: results in an inhibitory postsynaptic potential (IPSP), less likely the cell will fire
• their cell bodies may be in the CNS, but they have long axons which form part of the PNS
• motor neurons form synapses with muscles and control their contractions • a nerve cell can receive both EPSPs and IPSPs at the same time
• when stimulated, the motor neuron releases neurotransmitters that bind to receptors on the muscle and triggers → therefore, likelihood of cell firing is determined by adding the excitatory and inhibitory synaptic input
a response which leads to muscle movement → the net result of this calculation (known as summation) determines whether or not the cell fires
• when the axon of a motor neuron fires, the muscle with which it has formed synapses with contracts • the strength of an EPSP can be increased in two ways
• strength of muscle contraction depends on the rate of firing axons of motor neurons that control it → Spatial Summation = a large number of EPSPs are generated at many different synapses on the same ---------------
• muscle relaxation is caused by inhibition of the motor neuron ---------------------------- postsynaptic neuron at the same time
→ Temporal Summation = a large number of EPSPs are generated at the same synapse by a series of high -------------
--------------------------------frequency action potentials on the presynaptic neuron
• the rate at which a particular cell fires is determined by what goes on in the synapses
→ if excitatory synapses are more active, the cell fires at a high rate
→ if inhibitory synapses are more active, the cell fires at a much lower rate, if at all
, Endocrine System = network of glands in the body that manufacture and secrete chemical messengers (hormones) PITUITARY GLAND:
Pituitary Gland = the ‘master gland’, primary function is to influence the release of hormones from other glands, and --
----------------------- in doing so, regulate many of the body’s functions
GLANDS AND HORMONES:
• is controlled by the hypothalamus, a region of the brain just above the pituitary gland
Endocrine Glands = special group of cells in endocrine system, function is to produce and secrete hormones • the hypothalamus receives information from many sources about the basic functions of the body, the uses this
information to help regulate these functions
• major glands of endocrine system include pituitary gland, adrenal glands, and reproductive organs
• one of the ways to does this involve controlling the pituitary gland
• each gland produces different hormones, which regulate activity of organs and tissues in the body
• as the ‘master gland’, it produces hormones that travel in the bloodstream to their specific target
• the endocrine system is regulated by feedback
• these hormones either directly cause changes in physiological processes in the body or stimulate other glands
→ e.g. a signal is sent from hypothalamus to pituitary gland in the form of a ‘releasing hormone’
to produce other hormones
→ this causes the pituitary to secrete a ‘stimulating hormone’ into the bloodstream
• high levels of hormones produced in other endocrine glands can stop the hypothalamus and pituitary releasing
→ this hormone then signals the target gland (e.g. the adrenal gland) to secrete its hormone more of their own hormones
→ as levels of this hormone rises in the bloodstream, the hypothalamus shuts down secretion of the • this is called negative feedback, and prevents hormone levels from rising too high
releasing hormone and the pituitary gland shuts down secretion of stimulating hormone
→ this slows down secretion of the target gland’s hormone, resulting in stable concentrations of hormones HORMONES PRODUCED BY THE PITUITARY GLAND:
circulating in the bloodstream • pituitary gland has two main parts: the anterior (front) pituitary and the posterior (back) pituitary
→ these two parts release different hormones, which target different parts of the body
Hormones = body’s chemical messengers, each hormone ‘excites’/stimulates a particular part of the body → the two sections of the pituitary gland produce a number of different hormones, which act on different
→ they travel through the bloodstream, influencing many different processes including mood, the stress target glands or cells
response and bonding between mother and new born baby
• Anterior Pituitary releases:
• although hormones come into contact with most cells in the body, a given hormone usually affects only a → ACTH = stimulates the adrenal glands to produce cortisol – releases as a response to stress
limited number of cells, known as target cells • Posterior Pituitary releases:
→ target cells respond to a particular hormone because they have receptors for that hormone → Oxytocin = stimulates contraction of uterus during childbirth, important for mother- infant bonding
→ cells that do not have such a receptor cannot be influenced directly by that hormone
THE ADRENAL GLANDS:
• when enough receptor sites are stimulated by hormones, a physiological reaction occurs in target cell
• the two adrenal glands sit on top of the kidneys
→ timing of hormone release is critical for normal functioning, as are levels of hormones released
• the name ‘adrenal’ relates to their location
→ too much or too little at the wrong time can result in dysfunction of bodily systems
• each adrenal gland is made up of two distinct parts
→ for example, too high a level of cortisol can lead to Cushing’s syndrome, characterised by high blood
• the outer part of each gland is called the adrenal cortex and the inner region is known as the adrenal medulla
pressure and depression
• the adrenal cortex and the adrenal medulla have very different functions
• one of the main distinctions between them is that the hormones released by the adrenal cortex are necessary
• most common cause of excess cortisol is a tumour in the pituitary gland
for life, those released by the adrenal medulla are not
→ which makes too much of a hormone called adrenocorticotrophic hormone (ACTH) which stimulates
adrenal glands to make too much cortisol
HORMONES PRODUCED BY THE ADRENAL GLANDS:
• Adrenal Cortex produces:
→ Cortisol = regulates variety of bodily functions (inc. cardiovascular and inflammatory functions)
- cortisol production is increased in response to stress
- low cortisol level results in blood pressure, poor immune function, and an inability to deal with stress
• Adrenal Medulla releases: hormones that prepare the body for fight or flight
→ Adrenaline = helps the body response to a stressful situation
- e.g. by increasing heart rate and blood flow to the muscles and brain and helping with the conversion
of glycogen to glucose to provide energy
→ Noradrenaline = constricts the blood vessels, causing blood pressure to increase
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller kjakhu05. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.77. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
80796 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now