Psychology Chapter 3:
- Chromosomes consist of DNA
- DNA strands consist of complementary bases (Adenine binds with Thymine, Guanine binds with
Homozygous: child’s parents have contributed similar genes for a trait (BB, bb)
Heterozygous: child’s parent have contributed for different versions of genes (Bb)
The Central Nervous system and the Peripheral N.S
1- CNS: is composed of the brain and the spinal cord
2- Peripheral N.S: is divided into the somatic nervous system and autonomic nervous
Somatic N.S: controls voluntary muscles and sensory receptors (carrying
information from receptors in the skin, muscles and joints to the nervous
system and that carry commands from the CNS to muscles)
o Afferent nerve fibers: axons that carry information inward
to the CNS from the periphery of the body.(from body to
o Efferent nerve fibers: axons that carry information outward
from the CNS to the periphery of the body. (from CNS to
Autonomic: controls involuntary muscles such as blood vessels and glands
(things that people don’t normally think about such as digestion, heart rate
etc. or difficult to control reactions)
o Sympathetic: when the body is stressed (heart is beating
o Parasympathetic: When the body is calmed down
3- Neurons: basic cells in the nervous system that receive, integrate and transmit
Structure of the Neuron
1- Dendrites: parts of the neuron that are specialized to receive information
2- Soma (cell body): contains the cell’s body and much of the chemical machinery common
to most cells.
3- Axon: a long, thin fiber that transmits signals away from the soma to other neurons or
to muscles or glands. 4- Myelin Sheath: insulating material that speeds up the transmission of the signals that
move along axons.
5- Terminal buttons: end of the axons and are the ones that tranmist the
6- Synapse: a junction where information is transmitted from one neuron to another.
7- Glia Cells: Provide various types of support for neurons
1- Sensory neurons: bring information to the CNS
2- Interneurons: associate memory with sensory and motor activity in the CNS
3- Motor neurons: send signals from the spinal cord and the brain to muscles
Resting an Acting Potential
Resting potential: is its stable negative charge when the cell is inactive. (-70 MV)
Action Potential: a very brief shift in a neuron’s electrical charge that travels along an axon.
All – in none law: action potential is either fired or it isn’t
Post-synaptic potential: is divided in two different categories which include excitatory
(decreases negative charge (-55 MV) more positive) and inhibitory (increases negative charge -
70 MV more negative) P.S.P
1- Acetylcholine: only transmitter between motor neurons and voluntary muscles for
example typing, walking, breathing, talking. ACH also appears to contribute to attention,
arousal and memory.
2- Dopamine (DA): control of voluntary movement and pleasurable emotions.
Overactivity of DA can result in schizophrenia
3- Norepinephrine (NE): contributes to modulation of mood and arousal
4- GABA: seem to produce only inhibitory postsynaptic potential. Valium and similar
antianxiety drugs work at GABA synapses
5- Serotonin: involved in regulation of sleep and wakefulness, eating, aggression.
Abnormal levels may contribute to depression and obsessive- compulsive disorder.
Prozac and similar anti-depressant drugs affect serotonin circuits.
6- Endorphins: resemble opiate (soothing, creates inaction or dullness) in structure or
effects. Contribute to pain relief and perhaps to some pleasurable emotions.
Electroencephalograph: a device that monitors the electrical activity of the brain over time by
means of recording electrodes attached to the surface of the scalp.
- EEG recordings are translated into brain waves which give a useful overview of the
electrical activity in the brain.
Lesion: destruction of the brain tissue Computerized tomography (CT): a computer-enhanced X-ray of brain structure.
- Least expensive and has been widely used in research
- Used to look for abnormalities in the brain
- a series of x-