Psychology Chapter 3: Biological Foundations

Study Notes

The nervous system comprises all neural tissue, classified into the central nervous system (CNS) and peripheral nervous system (PNS).
CNS consists of the brain and spinal cord; PNS includes all remaining neural tissue in the body.
Afferent nerves relay signals from the body to the CNS, while efferent nerves carry signals from the CNS to the body.

Neurons are the core components of the nervous system, specialized for transmitting neural impulses and signals.
Dendrites: short branches from the cell body (soma) that receive impulses from other neurons.
Axon: a slender tube extending from the soma that transmits messages to other neurons.
Terminal buttons: tiny branches at the end of the axon that contain synaptic terminals, which do not touch adjacent neurons.
Synapse: the gap between terminal buttons of one neuron and the dendrites of another, facilitating communication.

When an impulse reaches terminal buttons, it triggers the release of neurotransmitters that cross the synaptic gap.
The post-synaptic neuron integrates information from multiple pre-synaptic neurons.
Myelin sheath: an insulating layer around axons that speeds up neural impulses, produced by glial cells.

Non-neuronal cells that support the nervous system, outnumbering neurons by a ratio of 9 to 1.
Functions include holding neurons in place, supplying nutrients, providing insulation, and clearing waste and dead neurons.
Oligodendrocytes produce myelin in the CNS, while Schwann cells fulfill the role in the PNS.

Sensory neurons: transmit impulses from receptors to the CNS, detecting physical or chemical changes.
Motor neurons: carry outgoing signals from the CNS to muscles and glands.
Interneurons: connect sensory and motor neurons, exclusively located in the CNS and eyes.

A nerve comprises a bundle of axons from numerous neurons.
The optic nerve serves as an example, transmitting signals from the eye to the brain.
Neuron cell bodies in the CNS are termed nuclei; those outside are called ganglia.

Neurons transmit signals using electric impulses, organized in chains for efficient communication.
Chemical transmission occurs at synapses, enabling rapid signaling between neurons.
This signaling allows for quick responses, such as dropping a hot object before conscious realization.