B6 Flashcards
What two systems in the human body are used for communication?
The nervous system and the hormonal system
What does the nervous system do?
To send electrical signals using nerves known as neurons
What does the hormonal system do?
It sends chemical messages in the form of hormones
Compare the signals sent by each system
Nervous system : quick, short lasting responses
Hormonal system : slow, long lasting responses
How is the nervous system in mammals composed?
It is made of the central nervous system (CNS), the brain and the spinal chord, and the peripheral nervous system (PNS) which connects the central nervous system to the rest of the body
A receptors job is to…
detect changes in the environment
Our eyes and ears are examples of receptors
Effectors are…
the organ or gland that responds to external stimuli after the signal has been passed along the nervous system
Name the 3 type of neurons and what they do
Sensory - connect to receptors to the CNS
Relay - found in the CNS, takes message from the sensory neuron to the motor neurone
Motor neuron - connects the CNS to the effector
How are hormones transported?
Through the blood but they only affect the ‘target cells’
What does a neuron consist of?
Cell body Dendrites Nucelus Axon Myelin sheath
What do dendrites do?
They receive the signals from other neuron or receptors
What is the function of the axon?
It carries the electrical impulses away from the cell body. It is an extension of the cytoplasm
What is the function of the myelin sheath?
To insulate the neuron from other cells
Name the 3 factors that affect the sped at which a nerve signal is sent
The temperature - signals are always faster in warm blooded animals
The diameter of the axon
The condition of the myelin sheath - the signal can ‘jump’ between the gaps in the myelin sheath speeding up the signal
What is the name of the gap between neurons?
Synapse
Why don’t neurons touch?
So they can communicate with several different neurons at once
How does a signal pass from one neuron to the next?
As the electrical signal reaches the end of the pre-synapse neuron, the appropriate neurotransmitter is triggered and released from the vesicle where it is stored. Theses diffuse across the synapse and bind with the appropriate receptor which triggers and electrical signal to start in the post-synpase neuron
What happens to neurotransmitters after they have bound with receptors?
They are released to be reabsorbed by the neuron or broken down by an enzyme
How do drugs like ecstasy and anti depressants affect neurotransmission?
They prevent the reabsorption of neurotransmitters for a period of time allowing them to remain in the synapse and able to trigger the post-synapse neutron more frequently. These drugs often stop serotonin or dopamine reabsorption allowing the person taking them to feel happier for longer
What is a reflex?
An instantaneous response to a stimulus
What is the name of the pathway that the signal travels when a reflex happens?
A reflex arc
Give the stages of a reflex arc
stimulus → receptor → sensory neuron → relay neuron in CNS → motor neuron → effector
Why are many reflexes unlearned?
To protect us at an early age
The grabbing reflex is one of the early reflexes people have as a baby
Why are reflexes so quick?
They use fixed pathways that do not involve the brain therefore don’t require time for us to think about
If reflexes don’t require thinking, why is there a part of a reflex arc that joins to the CNS?
So we know whats happened after the reflex occurs
So we are able to override the action if we want to e.g hold a hot object to prevent us from dropping it
What is instinctive behaviour?
Unlearned behaviour linked to reflex actions
What is conditioning?
Teaching instinctive behaviour by introducing a unrelated stimulus to create an association with the other
Explain the Pavlov’s dog experiment
Pavlov got dogs to look, smell and see their food which caused them to salivate. He rung a bell and then allowed them to eat. This was repeated every time the dogs ate. After a period of time when the dogs heard the bell they salivated as they associated it with the food
What was the primary and secondary stimuli in Pavlov’s experiment?
Primary stimulus : the food
Secondary stimulus : the bell
Explain the Little Albert experiment
Baby Albert was not afraid of a lab rat that was shown to him by scientist, John Watson. Albert was then shown the rat and Watson made a loud noise that made Albert cry. Later on when Albert was shown the rat he became distressed
What was the primary and secondary stimulus is the Little Albert experiment?
Primary stimulus : the noise
Secondary stimulus : the rat
Explain the difference between the primary and secondary stimulus
The primary stimulus is what causes the initial reaction
the secondary stimulus is what the initial reaction becomes associated with
Whats are conditioned reflexes?
Simple learned responses that lead to increased survival such as if you see a car coming towards you, you move out if its way
Where is the cerebral cortex?
It is the thin , folded outer layer of our brain
What parts of human development is the cerebral cortex involved in?
Memory
Intelligence - problem solving
Language - how we communicate
Consciousness - being aware of our surrounding
What does a larger number of folds in the cerebral cortex increase?
the ability to process information
What invasive methods are used by neuroscientists to map regions of the brain?
Studying the effects of serious brain injury on a persons everyday abilities
Using electrodes to stimulate regions of the brain during brain surgery
What non-invasive methods are used by neuroscientist to map regions of the brain?
MRI scanners to help compare non illness damaged brains to brains of people with Alzheimer’s or Parkinson’s
Transmitting impulses in the brain leads to…
neuron pathways forming
How can neuron pathway be strengthened?
By repeating an experience or thinking process
By strong stimuli such as light, colour, sound
What defines learning?
An experience where new neutron pathways are formed and theses pathways are more likely to transmit impulses than others
What are sensitive periods?
The time in which a child must learn a skill (such as speaking or walking) or it could potentially never bethought to them
What are feral children?
Children who have lived away from human contact who have not developed skills such as speech, social interaction or even being able to walk
Memory is defined as…
The storage and retrieval of information
What is short term memory?
The information of our most recent experience which is only stored for a brief period of time
What is long term memory?
Information of our earliest experience onwards that can be stored for long periods of time
How can you increase the probability you’ll remember something?
If there is a pattern to somethings
If you repeat it several times over a long period with rests
By creating a strong association with a stimuli such as a smell, sound or colour
How do scientist try to explain how we store memories?
Using models
What is the multi-store model?
The model that splits memory into 3 blocks:
Sensory memory that lasts 1-3 seconds
Short term memory that lasts 15- 30 seconds
Long term memory that last 1 second to a life time
Paying attention transfers sensory memory into short term, rehearsal transfers short term into long term
Memory can be lost from each store due to biological factors or lack of rehearsal
Why are memory models flawed?
Memory is a lot more complex
they don’t provide an exact explanation of how long term memory works
Often don’t provide subdivision between short term and long term
Doesn’t take into account individuals response to stimulus and different types of stimuli
