Pavlov’s Dogs Pavlov had observed that an unconditioned stimulus causes an unconditioned response, i.e. food causes salivation. This is not learned and is, therefore, unconditioned. What Pavlov discovered was that if a neutral stimulus, such as a bell is rung just...
In Parkinson’s disease neurons in the brain die. All these neurons secrete dopamine neurotransmitter, which causes difficulty in movement and limb shaking. In depression neurons in the brain that secrete serotonin neurotransmitter stop working properly and...
Drugs that affect synapses can drastically alter the functioning of the brain; MDMA: Active ingredient in ecstasy. This binds to protein pumps on the pre-synaptic membrane of nerves that secrete serotonin. The pumps would normally take serotonin up after it...
Continuous variation: there is a wide range of phenotypes (e.g. height) Discontinuous variation: phenotypes fall into discrete categories (e.g. blood type) Discontinuous variation tends to be coded for by one gene with a few different alleles. However,...
Brain development is a combination of nature and nurture.
How to process stimuli correctly must be learned. The cortex is split into column of cells. When we are born, the columns overlap and are tangled. As we learn to process stimuli, the cells organise themselves into discrete columns, which no longer overlap. There is a...
The Muller-Lyer illusion; Lines A and B are the same length, yet look different – why? The answer is that you have learned to process this kind of stimuli in a certain way. We live in a “carpentered world” of straight lines and we interpret line B as a corner...
Association (classical conditioning): US ® UR (Food ® Salivation) Over time, if a neutral stimulus (CR) is played with the US, it becomes associated with the US and begins to elicit the same response. Eventually, the animal learns CS ® CR (Bell ®...
Hindbrain Brainstem – Uppermost part of the spine, where the spine joins the brain. Medulla - controls vital ‘housekeeping’ functions, such as heartbeat, blood pressure and peristalsis. Cerebellum - controls muscle co-ordination & learns motor programmes...
Visual transduction is the process by which light initiates a nerve impulse. The structure of a rod cell is: The detection of light is carried out on the membrane disks in the outer segment. These disks contain thousands of molecules of rhodopsin, the...
Homeostasis is the maintenance of the internal environment. Nerve reflexes give immediate responses Hormone responses give responses over weeks – months Hormones are released from glands, which release hormone into the blood. The hormone is carried all over the body....
A synapse is the junction between two nerves. It is also a verb, i.e. one nerve synapses with another (meaning, passes a message to another). The neurotransmitter on your syllabus is Ach, but over 2000 other transmitters have been discovered. The wave of...
Sequence of events in an action potential; Nerve is at resting membrane potential (-70mV) A stimulus depolarises the nerve to threshold (-50mV) Voltage-gated Na+ Channels open Sodium floods into the cell and the membrane potential depolarises to +30mV...
Sensory nerve: carries electrical message from receptor to spine Motor nerve: carries electrical message from spine to effector. Relay nerve: connects sensory and motor nerves. Also relays message to the brain....
High light intensity Circular muscles: contracted Radial muscles: relaxed Pupil diameter: small Low light intensity Circular muscles: relaxed Radial muscles: contracted Pupil diameter: large