Chapter 3: Biological Foundations of BehaviourThe Neural Bases of Behaviour To understand how the brain controls our experience and behaviour, we must first understand how its individual cells function and how they communicate with one another. Neuronsspecialized cells that are the building blocks of the nervous system linked together in circuitsat birth, brain contains about 100 billion neurons3 main parts: ocell body/soma - contains biochemical structures needed to keep the neuron alive, its nucleus which carries the genetic information that determines how the cell dvps and fxns, combines and processes incoming info from the: odendrites - which emerge from the cell body, are specialized receiving units that collect messages from neighbouring neurons and send them on to the cell body. can receive input from 1000+ neighouring neurons oaxon: conducts electrical impulses, away from the cell body to other neurons, muscles, or glands. branches out with possibly several hundred axon terminals. May connect with dendritic branches from many neurons. vary greatly in size and shape.200+ types have been ID-ed with electron microscopes Regardless of shape/size are exquisitely sculpted by nature to perform their function of receiving, processing and sending messages. are supported by GLIAL CELLS. osurround neurons and hold them in place.
omanufacture nutrient chemicals that neurons needoform the myelin sheath around some axonsoabsorb toxins and waste materials that might dmg neurons. oDuring prenatal brain dvp, as new neurons are being formed through cell division, glial cells send out long fibres that guide newly divided neurons to their targeted place in the brain. omodulate communication amongst neuronsooutnumber neurons 10 to 1 oblood-brain barrierThe Electrical Activity of Neurons Neurons do two important things; generate electricity that creates nerve impulses. Also release chemicals that allow them to communicate with other neurons and with muscles and glands. Nerve Impulses:1.At rest, the neuron has an electrical resting potential due to the distribution of positively and negatively charged chemicals (ions) inside and outside the neuron. Neurons are surrounded by bodily fluidsand separated from this liquid environment by a protective membrane.2.This cell membrane is semi-permeable, allowing only certain substances to pass through via ion channels. 3.In the fluid outside the neuron are positively charged Na+ and negatively charged Cl-. 4.Inside the neuron are large negatively charged protein molecules (A-) and positively charged K+.5.The high concentration of Na+ in the fluid outside the cell, together with the negatively charged protein inside the neuron results in the uneven distribution of positive and negative ions that makes the