Biopsychology AO1 - up to fight or flight Flashcards
What is the Nervous System?
A specialised network of cells in the human body that is our primary internal communication system
What types of signals is the Nervous System made up of?
Chemical and Electrical
What are the 2 main functions of the Nervous System?
1) To collect, process and respond to information in the environment
2) To co-ordinate different organs and cells in the body
What are the 2 sub-systems of the Nervous System?
The Central Nervous System
The Peripheral Nervous System
What does the CNS stand for?
Central Nervous System
What does the PNS stand for?
Peripheral Nervous System
What is the CNS made up of?
Brain and Spinal cord
What is the function of the Brain in the CNS?
It is the centre of all conscious awareness
It is divided into 2 hemispheres (Left and Right)
What is the function of the Spinal Cord in the CNS?
It is an extension of the brain
It passes messages to and from the brain
It connects to the PNS
It is responsible for reflex actions
What does the CNS do?
Connects nerves to the PNS to pass messages
What does the PNS do?
Transmits messages to and from the CNS via millions of neurons
How many subdivisions does the PNS have?
2
How many components are in the CNS?
2
What are the 2 subdivisions of the PNS?
The Autonomic Nervous System
The Somatic Nervous System
What does the Autonomic Nervous System do?
Governs vital functions in the body
e.g. breathing, heart rate, digestion, sexual arousal, stress responses
What does the Somatic Nervous System do?
Governs muscle movement and receives information from Sensory Receptors
How many states can the Autonomic Nervous System be in?
2
What are the 2 states the ANS can be in?
Sympathetic
Parasympathetic
What is the ANS’ resting state?
Parasympathetic
When does the ANS change to a sympathetic state?
When adrenaline levels rise (fight or flight)
Define Nucleus
The control centre of cells containing chromosomal data
What does a Dendrite do?
Receives nerve impulses (signals) from adjacent neurons
What is an Axon?
Where electrical signals pass along
What does the Myelin Sheath do?
Insulates and protects the axon from external influences that might affect the transmission of the nerve impulse
What is the Myelin Sheath?
A fatty layer surrounding the Axon
What do the nodes of Ranvier do?
Speed up the transmission of the impulse by forcing it to ‘jump’ across the gaps
What do Terminal Buttons do?
Send signals to adjacent cells by communicating across the synaptic gap
Name all the parts of a neuron:
Nucleus
Dendrites
Axon
Myelin Sheath
Nodes of Ranvier
Terminal Buttons
*How many neurons are in the Human Nervous System?
Around 100Billion
*What percentage of neurons are in the brain?
80%
What is the purpose of neurons?
To provide the nervous system with a means of communication by transmitting chemical and electrical signals
How many types of neuron are there?
3
What are the 3 neurons called?
Sensory Neurons
Relay Neurons
Motor Neurons
What order do signals pass through the neurons in?
Sensory –> Relay –> Motor
What direction do Dendrites carry the signal?
Towards the cell body
What direction does the Axon carry the signal?
Away from the cell body
What are the segments of Myelin Sheath called?
The Nodes of Ranvier
How does Electrical Transmission work?
- When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second
- An action potential occurs
- This creates an electrical impulse that travels down the axon to the end of the neuron
Where are Sensory Neurons located?
They are found in clusters called Ganglia in the Peripheral Nervous System
Where are Relay Neurons located?
They are in the brain and visual system
Where are Motor Neurons located?
In the CNS
Their axons are part of the PNS
Where is the Cell Body located on Sensory Neurons?
The Side of the Axon
What is the function of Sensory Neurons?
- They sense the activity from the Sensory Receptors in the Peripheral Nervous System
- They carry the nerve impulses from the PNS to the CNS to send their message to the brain
What are the features of Sensory Neurons?
Long Dendrites - so they can feel more
Short axons - to send messages quickly
Cell body sits on the side of the axon
Where is the Cell Body located on Relay Neurons?
In the Middle of the Neuron (the middle neuron)
What is the function of Relay Neurons?
They relay information from the Sensory Neurons to the Motor Neurons
They act as messengers
They also carry messages back from the brain to the Motor Neurons
What are the features of Relay Neurons?
Short Dendrites
Short or Long Axons
Cell body in the middle of neuron
Where is the Cell Body located on Motor Neurons?
The end of the Cell Body (around cell body)
What is the function of Motor Neurons?
They produce a response by transmitting messages to an effector
What is an effector?
A muscle or gland - moves or secretes/inhibits hormone to change body’s functioning
What are the features of Motor Neurons?
Short Dendrites
Long Axons
Cell body at the end of the Axon
What is the Endocrine System?
A network of glands throughout the body that manufacture and secrete hormones.
It works with the Nervous System to regulate the physiological processes of the body.
It uses Blood Vessels to deliver hormones from their glands to their target sites.
What are hormones?
Chemical Messengers that circle the body in the bloodstream to effect target sites
How do hormones travel from their gland to the target site?
Blood Vessels
What are target sites?
The desired recipient of a hormone.
They have target cells with receptors for the hormone they want to receive.
Is the Endocrine System faster or slower than the Nervous System?
Slower
What does the Endocrine System control?
Vital functions in the body through producing and secreting hormones
What are the major glands in the Endocrine System?
The Pituitary Gland
The Adrenal Glands - Adrenal Medulla and Adrenal Cortex
Ovaries
Testes
Where is the Pituitary Gland situated?
In the Brain
What is the function of the Pituitary Gland?
It is the master gland
It controls the release of hormones from all other glands
Where are the Adrenal Glands located?
On top of the Kidneys
What are the 2 Adrenal Glands?
Adrenal Medulla
Adrenal Cortex
What is the outer Adrenal Gland called?
Adrenal Cortex
What is the inner Adrenal Gland called?
Adrenal Medulla
What is the function of the Adrenal Cortex?
To increase blood pressure and the ability to respond to stress
What hormone does the Adrenal Cortex secrete?
Cortisol
What hormone does the Adrenal Medulla secrete?
Adrenaline
What is the function of the Adrenal Medulla?
To increase heart rate and blood flow for fight or flight
Where are the Ovaries situated?
In the Female Reproductive System
What do the Ovaries produce?
Eggs
Oestrogen
Progesterone
What is the function of the Ovaries?
To secrete oestrogen to create a suitable environment for fertilisation and implantation
Where are the Testes situated?
In the Male Reproductive System
What do the Testes produce?
Testosterone
What are Neural Networks?
The neurons that communicate with each other within a group
What is a Synapse?
The gap separating each neuron from its adjacent neuron
How are signals transmitted between neurons?
Chemically
How are signals transmitted within neurons?
Electrically
What are Neurotransmitters?
Chemicals that diffuse across the synapse to the post-synaptic receptors in the next neuron
What happens when Neurotransmitters reach the post-synaptic receptor site in the dendrites of the next neuron?
They change from a chemical signal to an electrical impulse to continue their journey
Why can direction of synaptic transmission only be one way?
The neurotransmitters are released from pre-synaptic neuron terminals and are received by post-synaptic neurons at matching receptor sites.
The neurotransmitters will fit into a receptor site with its matching molecular structure so they fit like a lock and key.
Each one is different as each neurotransmitter is coded with a specific function.
What is Inhibition?
The neurotransmitter will make the receiving neuron more negatively charged, meaning it is less likely to fire
What is Excitation?
The neurotransmitter will make the receiving neuron more positively charged, meaning it is more likely to fire
What is an example of an Inhibitory Neurotransmitter?
Serotonin
What is an example of an Excitatory Neurotransmitter?
Adrenaline
What is Summation?
The process that decides whether or not a postsynaptic neuron fires by summing the excitatory and inhibitory influences
What is the process of Summation?
Adds all the excitatory and inhibitory influences on the neuron together:
- If the net effect on the postsynaptic neuron is inhibitory, it is less likely to fire
- If the net effect on the postsynaptic neuron is excitatory, it is more likely to fire as the inside of the postsynaptic neuron becomes positively charged momentarily. This electrical impulse allows it to travel down the neuron.
At what point is the Action Potential triggered (on the post synaptic neuron)?
If the sum of the excitatory an inhibitory signals at any one time reaches the the threshold
What are Neurotransmitters released from?
Synaptic Vesicles
What is the process of Synaptic Transmission?
1) A neuron is activated by a stimulus, causing the inside to become positively charged for a split second
2) This causes an action potential to occur, creating an electrical impulse that travels down the axon towards the end of the neuron
3) When the electrical impulse reaches the end of the neuron (the presynaptic terminal), it triggers the release of neurotransmitters from synaptic vesicles
4) The neurotransmitters diffuse across the synaptic gap to its postsynaptic receptor site on the dendrites of the next neuron
5) The neurotransmitters will either have an excitatory or inhibitory effect on the neighbouring neuron
6) The postsynaptic neuron will decide whether it fires or not based on the process of Summation
Which 2 systems work together during Fight or Flight?
The Endocrine System and the Autonomic Nervous System
What is the process of Fight or Flight?
1) A stressor is perceived
2) The hypothalamus in the brain activates the pituitary gland, which triggers activity in the sympathetic branch of the Autonomic Nervous System
3) The ANS changes from its normal parasympathetic resting state, to the physiologically aroused sympathetic state
4) The Sympathetic Nervous System sends a message to the Adrenal Medulla
5) The adrenal medulla releases the hormone adrenaline
6) Adrenaline circulates through the blood stream and causes changes that allows someone to either fight or flight
7) The stressor passes
8) The parasympathetic branch of the ANS reverses the changes made to bring the body back to its normal resting state
How long does the process of fight or flight take?
It is immediate and automatic
Where is the Hypothalamus?
In the brain
What does the Hypothalamus activate in Fight or Flight?
The Pituitary Gland
What does the Pituitary Gland do in Fight or Flight?
It triggers activity in the Sympathetic branch of the ANS
Which nervous system is involved in fight or flight?
The Autonomic Nervous System
What gland does the sympathetic nervous system signal to?
The Adrenal Medulla
What hormone is secreted in Fight or Flight?
Adrenaline
What are some physiological changes that happen when the ANS goes from parasympathetic to sympathetic?
Increased heart rate - increase blood flow to organs and movement of adrenaline
Increased breathing rate - increase oxygen intake
Pupil Dilation - Increase light entry into the eye and enhance vision
Sweat production - Regulate temperature
Reduction of non-essential productions (salivation, digestion, urination) - to increase energy of other functions
What are some physiological changes that happen when the ANS goes from sympathetic to parasympathetic?
Decreased heart rate
Decreased breathing rate
Constricts Pupils
Stimulates Digestion
Stimulates Salivation
Relaxes rectum
