Paper 2 - Biopsychology Flashcards
What is the nervous system
A specialised network of cells and the primary communication system in the body
What are the two main functions of the nervous system
To collect, process and respond to information in the environment.
To coordinate the working of different organs and cells in the body.
What is the nervous system divided into
The central nervous system and the peripheral nervous system
What is the central nervous system
Consists of the brain and spinal cord and is the origin of all complex commands and decisions
What is the peripheral nervous system
Sends information to the CNS from the outside world, and transmits messages from the CNS to muscles and glands in the body via millions of neurons
What is the outer layer of the brain called
The cerebral cortex
What is the cerebral cortex
The surface layer of the forebrain (the two hemispheres). It is grey in colour and is highly folded to make it possible to fit the massive amount of material inside the skull
What distinguishes our higher mental functions from those of animals
The cerebral cortex as it’s highly developed
What is the spinal cord responsible for
It’s an extension of the brain and is responsible for reflex actions. It passes messages to and from the brain and connects nerves to the PNS
What is the PNS subdivided into
The autonomic nervous system and the somatic nervous system
What is the autonomic nervous system
Transmits information to and from internal bodily organs. It is autonomic as the system operates involuntarily. It has two main divisions: the sympathetic and parasympathetic nervous systems
What vital functions does the ANS govern
Breathing, heart rate, digestion, sexual arousal and stress response
What is the somatic nervous system
Transmits information from receptor cells in the sense organs to the CNS. It also receives information from the CNS that directs muscles to act
What is the endocrine system
One of the body’s major communication system that instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target organs in the body.
What does the endocrine system release
Hormones. It works much slower than the nervous system but has widespread and powerful effects
What is a gland
An organ in the body that synthesises biochemical substances such as hormones
What produces hormones
Glands
What is a hormone
Biochemical substances that circulate in the bloodstream and control and regulate the activity of certain cells or organs. Hormones only affect target organs. They are produced in large quantities but disappear quickly. Their effects are very powerful
What is the major endocrine gland
The pituitary gland, located in the brain
What is the pituitary gland
Called the master gland of the body’s hormone system because it controls the release of hormones from all the other endocrine glands in the body
What do hormones do
They get secreted into the bloodstream and affect any cell in the body that has a receptor for that particular hormone
Example of of a hormone
Thyroxine produced by the thyroid gland affects cells in the heart and also cells throughout the body which increases metabolic rates. This in turn affects growth rates
What do the endocrine system and the autonomic nervous system work together to produce
The fight or flight response
What is the fight or flight response
The way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an aggressor or in some cases flee
How do the endocrine system and the ANS work to produce the fight or flight response
When a stressor is perceived, the hypothalamus triggers activity in the sympathetic branch of the ANS. the ANS changes from its testing state (the parasympathetic state) to physiologically aroused sympathetic state.
The stress hormone adrenaline is released from the adrenal medulla into the blood stream.
Adrenaline triggers physiological changes in the body e.g increased heart rate known as the fight or flight response.
What happens during the fight or flight response once’s the threat has passed
The parasympathetic nervous system returns the body to its resting state. This acts as a ‘brake’ and reduced the activities of the body that were increased by the actions of the sympathetic branch
What is the parasympathetic response after the fight or flight response sometimes referred to as
The ‘rest and digest’ response
What is adrenaline
A hormone produced by the adrenal glands. These are part of the human body’s immediate stress response. Adrenaline has a strong effect on the cells of the cardiovascular system - stimulating the heart rate, contracting blood vessels and dilating air passages
What is the hypothalamus
A small subcortial brain structure which plays a major role in the body’s stress response and maintaining a state of balance (homoeostasis) by regulating many of its key processes such as heart rate and body temperature. The lateral hypothalamus (LH) and the ventro-medial hypothalamus (VMH) start and stop eating
What are endocrine glands
A group of organs in the body that release hormones into the blood stream
How many neurons are in the human nervous system
100 billion
What percentage of all neurons in the nervous system reside in the brain
80%
What two ways do neurons transmit signals
Electrically and chemically
What are the three types of neurons
Motor
Sensory
Relay
What do motor neurons do
Carry messages from the CNS to effectors such as muscles and glands.
Short dendrites and long axons.
What are dendrites
Branching projections from the end of a neuron that carry nerve impulses from neighbouring neurons towards the cell body
What are axons
The long projection of the neuron from the cell body
What do sensory neurons do
Carry messages from the PNS to the CNS.
Long dendrites and short axons.
What do relay neurons do
Connect sensory neurons to motor neurons or other relay neurons.
Short dendrites and short axons.
What is a neuron
The basic building blocks of the nervous system, neurons are nerve cells that process and transmit messages through electrical and chemical signals
What is the basic structure of a neuron
The cell body (soma) has a nucleus.
Branch-like structure called dendrites from the cell body.
The axon covered in a fatty layer of myelin sheath.
Gaps in the sheath called nodes of Ranvier.
End of the axon has terminal buttons.
What is the purpose of a nucleus
It contains the genetic material of a cell and is the control centre of a cell
What is the purpose of dendrites
They carry nerve impulses from neighbouring neurons towards the cell body
What is the purpose of the axon
Carries the electrical impulse away from the cell body down the length of the neuron
What is the purpose of the myelin sheath
To protect the axon and speed up electrical transmission
What is the purpose of nodes of Ranvier
To speed up the transmission of the impulse
What is the purpose of terminal buttons
They communicate with the neighbouring neuron by releasing neuron transmitters across the synapse
When a neuron is in a resting stage, what is the inside of the cell compared to the outside
Negatively charged
How does an action potential occur
When a neuron is activated, the inside of the cell becomes positively charged for a split second causing an action potential
What is an action potential
A short increase and decrease of electrical activity in the membrane of a neuron, transmitting a signal away from the cell body.
What does an action potential in a neuron create
an electrical impulse that travels down the axon towards the end of the neuron.
What is each neuron separated by
A tiny gap called the synapse
What is the synapse
The gap between the postsynantic and presynaptic neuron
What is the difference between signals transmitted within the neuron and those transmitted across the synapse
Within the neuron the signals are transmitted electrically but between each neuron they are diffused chemically
When the electrical impulse reaches the presynaptic terminal, what does it trigger
The release of neurotransmitters from tiny sacs called synaptic vesicles
What is the presynaptic terminal
The end of the transmitting neuron, ending at a synapse
What is a neurotransmitter
Brian chemicals released from synaptic vesicles that relay signal across the synapse from one neuron to another
What are synaptic vesicles
Small sacs at the end of a presynaptic neuron that contain neurotransmitters that will be released into a synapse
When a neurotransmitter has crossed the synapse, what happens
It is taken up by the postsynaptic receptor sure in the next neuron. The chemical message is converted back into an electrical impulse and the process of transmission begins again
What is the postsynaptic receptor site
A receptor on the neuron that is receiving the information at the synapse. A neurotransmitter locks into a specific receptor on the receiving neuron and this triggers an electrical signal in the receiving neuron
What does each neurotransmitter have
It’s own specific molecular structure that fits perfectly into a postsynaptic receptor site
Example of a neurotransmitter
Acetylcholine (ACh) is round at each point where a motor neuron meets a muscle, causing muscles to contract
What effects can neurotransmitters have on neighbouring neurons
Excitatory or inhibitory effects
What is excitation
When a neurotransmitter, such as adrenaline, increases the positive charge of the post synaptic neuron. This increases the likelihood that the neuron will fire and pass on the electrical impulse
What is inhibition
When a neurotransmitter, such as serotonin, increases the negative charge of the postsynaptic neuron. This decrease the likelihood that the neuron will fire and pass on the electrical impulse
What effects does dopamine have
Both inhibitory and excitatory effects in roughly equal measure
In the early 19h century, what did scientists believe of the brain
That all parts of the brain were involved in processing thoughts and actions - holistic theory.
After the 19th century, what was discovered about the brain
That specific areas of the brain were associated with particular physical and psychological functions - localisation theory. If a certain area of the brain becomes damaged through illness or injury, the function associated with that part will also be damaged .
What is localisation or function
The theory that different areas of the brain are responsible for different behaviours, processes or activities
What is hemispheric lateralisation
The idea that two halves (hemispheres) of the brain are functionally different and that certain mental processes and behaviours are mainly controlled t one hemisphere rather than the other as in the example of language (which is localised as well as lateralised)
What does the right hemisphere control
The left-hand side of the body
What does the left hemisphere control
The right-hand side of the body
How thick is the cerebral cortex
3mm
Why does the cerebral cortex appear grey
Due to the location of cell bodies
What is the cortex of both hemispheres divided into
Frontal
Parietal
Occipital
Tempeotal
What is the frontal lobe
Area of the brain responsible for logical thinking and making decisions
Where is the motor cortex
At the bad of the frontal lobe
What does the motor area control
Voluntary movement on the other side of the body.
What may damage to the motor area result in
A loss of control over fine motor movements
Where is the somatosensory area
At the front of both parietal lobes
What is the somatosensory area
It’s where sensory information from the skin (related to touch, heat, pressure etc) is represented.
What denotes a body parts sensitivity
The amount of somatosensory area devoted to a particular body part