B6 revision

Memory is divided into two sections: short term and long term.

Short term: capable of storing a limited amount of information for a short time e.g. A phone number.

Long short: capable of storing an unlimited amount of information for a long time e.g. Exam revision

Multi-store model:
Sensory memory retrieves information for a few seconds from our surroundings, but then is lost because it is of no significance or not enough focus was given.
If more focus is given the information goes into short term memory which lasts for a bit longer 15-30 seconds. Unless this is information is rehearsed and repeated (to make it go into long term memory), the information will be lost.

CNS (central nervous system) consists of the brain and spinal cord.
PNS (peripheral nervous system) consists of sensory neutrons and motor neurons.

A nerve impulse is a message sent along a nerve. A neuron is not a nerve.

In a neutron:
A cell body, surrounded by dendrites. has an axon extending from it, which carries the nerve impulses away to the axon terminal.

The axon is surrounded by a fatty myelin sheath which winds itself around the axon.
This insulates the axon, and speeds up impulses.

Neurotransmitters travel through a sensory neuron and motor neuron.

The neurotransmitter molecules diffuse through the gap between the synapses and are receive by a receptor molecule. These molecules are broken down then reabsorbed into neurotransmitter .

Prozac blocks synapses so serontonin molecules cannot be reabsorbed.

Stimulus->
Receptor cell ->
Sensory neutron ->
Coordinator (CNS) relay neuron->
Motor neuron ->
Effector (muscle/gland) ->
Response

Non invasive methods:

• fMRI (large magnetic field. Detects which areas of the brain are more active by seeing which areas have more blood flowing to them. Low risk of damage; no use of ionising radioation but anything metal can cause problems)
• CAT scan (using x rays to detect tumours)
• PET scan (uses anti matter. Relies on activity in the brain shown by where most blood flow is. Big risk as ionising radiation is used.)

Invasive:

• surgery
• electrical stimulation

Also do an autopsy to see if brain has got a disease or see effects of trauma.

A reflex is an involuntary action that increase chance of survival.
E.g.
When exposed to bright light p, the pupil constricts, but when in dim light the pupil dilates, in order to absorb as much light as as possible; this is so we can be aware of our surroundings.

Other examples of reflexes are : grasping reflex, rooting reflex and stepping reflex.

A stimulus is a change in the environment.

A conditioned reflex is formed by building an association between a new stimulus and a stimulus that naturally triggers the response.

Pavlov saw that when a dog saw meat it salivated.
He started ringing a bell everytime the dogs ate the meat.
Soon he could ring the bell and the dogs would salivate without seeing the meat.
The dogs had associated the sound of the bell with eating the meat, and so prepared to eat meat whenever they heard the bell (salivated)
The dogs had been conditioned.