PYC1501 STUDY NOTES
THE HUMAN NERVOUS SYSTEM:
NEURONS:
Neurons are part of a communicaton network that infuences the manner in which the body
... [Show More] functons
The process by which message are relayed in neurons is called impulse conducton
Motor or eferent neurons carry messages from the spinal cord or the brain to the muscles and gland Sensory or aferent neurons carry messages from the environment to the spinal cord and the brain
Impulse conducton:
• Is a basis for all human behaviour
• Can contribute to individual diferences in behaviour
• Communicates informaton from the external and internal evironments
• Impulse conducton depends on the presences or absence of neurotransmiters
• Sensory energy has to be converted into electrochemical energy in order to be conducted as a nerve impulse • Speed and Strength remains the same
• The frequency increases by bigger stmuli
• The magnitude remains the same
• Impulse conducton is an all or nothing event
Impulses cannot be conducted during the absolute refractory period. A large stmulus can fre again during the refractory period.
Salutatory Conducton: The process by which an impulse moves much faster by jumping from node to node by travelling through the myelin sheaf. It occurs in a myelinated axon of a neuron.
During Impulse conducton the restng membrane potental occurs when the sodium ions are positvely charged and the potassium ions are positvely charged. The total electrical charge on the inside of the membrane is negatvely charged.
When the electrical charge is strong enough to exceed the threshold the restng membrane potental is changed into an acton potental
Endorphins: The experience of pleasure and the suppression of pain. Laughter, love and exercise
Acetylcholine: Related to memory and the contracton of skeletal muscles. Supports Wakeful behaviour and mental alertness.
Dopamine: Plays a role controlling motor behaviour and good mental health.
Gamma-aminobutyric acid: A neurotransmiter that is involved in the regulaton of excitability in the human brain. It controls muscle tone and helps to manage aggression and appette.
The opening across which one neuron communicates with another neuron is known as the synaptc cleft.
Adrenalin: Increases the heart rate and the contracton of blood vessels, skeletal muscles and heart muscle. It also speeds up metabolism and the release of glucose into the blood.
Serotonin: Found in the brain, digestve tract and blood. Helps regulate the sleep-wake cycle and temperature. Associated with seasonal depression.
The process of synaptc transmission:
1. Nerve Impulse stmulates terminal bouton
2. Vesicles atach to the membrane
3. Neurotransmiters are released
4. Cross the synaptc clef
5. Neurotransmiters atach to receptors on postsynaptc membrane
NB!!! LEARN THE PARTS OF THE BRAIN AND WHAT THEY ARE THERE FOR
Occipital: (Back of the brain)
Primary Visual area. Responsible for combining visual stmuli into meaningful paterns.
The integraton of sensory experiences takes place in the occipital lobes.
Parietal: (Somatosensory Cortex).
Bodily Sensatons such as touch, temperature, pressure and pain. [Show Less]