Biological Bases of Behavior2

8/6/2019 Biological Bases of Behavior2

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GENERALPSYCHOLOGY

CHAPTER II:


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The Nervous System is the bodys

electrochemical communicationcircuitry.

The field that studies the nervoussystem is called neuroscience , andthe people who study it are calledneuroscientist .


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The Nervous System is primarilycomposed of the Central NervousSystem and the Peripheral NervousSystem .


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1 . Complexity2. Integration3. Adaptability4. Electrochemical Transmission


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The brain and nervous system being complex allows

the individual to do activities of different kinds.

This is due to the orchestrationof the billions of cells in the brainand the nervous system.


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Integration refers to the ability

of the brain to pull informationtogether.


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Although the composition of the brain and thenervous system have hereditary foundation, bothhave the ability to constantly adapt to the changesin the body and the environment.

The term plasticity denotes thebrains special capacity formodification and change.


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The brain being the information processing system , powered byelectrical impulses and chemicalmessages allows the individual to

perceive and respond to stimuli.


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1. Afferent Nerves (Sensory Nerves)-transportinformation to the brain.

Stimulus Sensory Receptors Afferent Nerves Brain


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2 . Efferent Nerves (motor nerves)-carry the brainsoutput or response.

Brain Efferent Nerves Muscles (motor behaviour response)


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3 . Neural Networks-cluster of neurons that areinterconnected to process information by integratingsensory input and motor output.


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Peripheral Nervous System the network of nervesthat connect the brain and the spinal cord to otherparts of the body. It is divided into the somaticnervous system and the autonomic nervous system.


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Somatic Nervous System the division of the PNSconsisting of sensory nerves, whose function isto convey information to the CNS, and motornerves, whose function is to transmit

information to the muscles.

Autonomic Nervous System the division of thePNS that communicates with the bodys internal

organs. It consist of the sympathetic and theparasympathetic nervous systems.


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Sympathetic Nervous System the division ofthe autonomic nervous system that arouses

the body.

Pa r a symp a thetic Nervous System thedivision of the autonomic nervous systemthat calms the body.


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Soma or the cell body containsthe cells nucleus and is responsiblefor the cells health and well-being.

Dendrites receive messages fromother neurons.

Axon transmits information on toadditional neurons.


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TheM

yelin sheath is the layer offat cells that encases and insulatesmost axons which help speed upthe transmission of nerve impulse.


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The synapse is the branching end ofa neurons axon reach out to, butdo not touch, the dendrites.


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6 . Endo rp i ns are natural opiates that mainly stimulates the firing of neurons. It shields the body from pain and elevates feelings of pleasure.


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The G lial cells (neuroglia ) providechemicals that a neuron need tofunction properly.

they also serve as the clean up crew

by removing dead neurons and excessneurotransmitter substances.


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Sensory NeuronInterneuronsMotor Neurons


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Resting Potential -the stable negative charge ofan inactive neuron.

Action Potential -the brief wave of electricalcharge that sweeps down the axon during thetransmission of a nerve impulse.


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All-or-none Principle -once the electricalimpulse reaches a certain level of intensity, itfires and over all the way down to the axonwithout losing any of its intensity.


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The human brain has three

major components:

1 . the hindbrain;2. the midbrain; and3. the forebrain.


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The hindbrain is made up of

several smaller structuressuch as the medulla, thepons, and the cerebellum.


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The midbrain is composedof two parts:

1 . the reticular formation(a.k.a. reticular activating system or

RAS); and2. 2. the brainstem.


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The forebrain mainlyconsists the following:

1 . Cerebral cortex2. Limbic system3. Thalamus4. Hypothalamus

5. Hippocampus6. Amygdala


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1. Frontal lobe is largely responsible fora wide variety of human activities such

as:

languageattention

reasoningplanninggoal settingself monitoringdecision makingjudgmentlearning strategiesinterpreting others behaviour


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2. Parietal lobes receive andinterpret somatosensoryinformation.

3. Occipital lobes

4. Temporal lobes


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The Endocrine System is a set of glands that regulate theactivities of certain organs by secreting hormones to the

bloodstream.

These hormones are chemical messengers that aremanufactured by the glands in the system. The endocrine

glands include the pituitary, thyroid, parathyroid, andadrenal glands, the pancreas, ovaries, and testes.


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1. Pituitary Gland -is located at the base of theskull, regulates the secretion of growth hormone andcontrols all other endocrine glands. It is known asthe master gland.The anterior pituitary is controlled by thehypothalamus.

2 . Pineal Gland -also located in the brain, it secretesthe hormone melatonin, which regulates the sleepand wake cycle.


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3 . Thyroid Gland -locate inside the neck andsecretes a hormone called thyroxin that regulatesmetabolism (how fast the body burns its available

energy).

4 . Pancreas -controls the blood sugar level bysecreting the insulin and glucagons.


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5 . Adrenal Glands -one on top of each kidney,produces the main hormone cortisol (steroid).The adrenal glands regulate moods, energy, and theability to cope with stress.

They secrete epinephrine (adrenaline) andnorepinephrine (noradrenaline) in response to stress.

6 . Gonads -produces sex hormones responsible forprimary and secondary sex characteristics.

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Biological Bases of Behavior2