The brain and nervous system being complex allowsthe individual to do activities of different kinds.This is due to the orchestrationof the billions of cells in the brainand the nervous system.
Integration refers to the abilityof the brain to pull informationtogether.
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 thebrain’s special capacity formodification and change.
The brain being the informationprocessing system, powered byelectrical impulses and chemicalmessages allows the individual toperceive and respond to stimuli.
1. Afferent Nerves (Sensory Nerves)-transport information to the brain.Stimulus Sensory Receptors Afferent Nerves Brain
2. Efferent Nerves (motor nerves)-carry the brain’soutput or response.Brain Efferent Nerves Muscles (motor behaviour response)
3. Neural Networks-cluster of neurons that areinterconnected to process information by integratingsensory input and motor output.
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.
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 transmitinformation to the muscles.Autonomic Nervous System the division of thePNS that communicates with the body’s internalorgans. It consist of the sympathetic and theparasympathetic nervous systems.
Sympathetic Nervous System the division ofthe autonomic nervous system that arousesthe body.Parasympathetic Nervous System thedivision of the autonomic nervous systemthat calms the body.
Soma or the cell body containsthe cell’s nucleus and is responsiblefor the cell’s health and well-being.Dendrites receive messages fromother neurons.Axon transmits information on toadditional neurons.
The Myelin sheath is the layer offat cells that encases and insulatesmost axons which help speed upthe transmission of nerve impulse.
The synapse is the branching end ofa neuron’s axon reach out to, butdo not touch, the dendrites.
1. Acetylcholine (ACh) stimulates the firing of neurons and is involvedin the action of muscles, learning, and memory.Deficiency in ACh will involve decline in memory storage andAlzheimer’s disease.2. Dopamine mainly inhibits and helps control the voluntary movement.Dopamine affects sleep, mood, attention and learning (mainly inplanning, and the inhibition of irrelevant behaviours and ideas).3. Serotonin also primarily inhibits. It also regulates sleep andwakefulness, mood, attention and learning.
4. Gamma Aminobutyric Acid (GABA) helps to control the preciseness ofthe signal being carried from one neuron to the next.Low level of GABA is linked to anxiety.5. Norepinephrine usually inhibits the firing of neurons in the centralnervous system, but it excites the heart muscle, intestine, and urogenitaltract.Stress stimulates the release of norepinephrine. Too little norepinephrine isassociated with depression, and too much is linked with agitated and manicstates.
6. Endorphins are natural opiates that mainly stimulates the firing ofneurons. It shields the body from pain and elevates feelings of pleasure.
The Glial cells (neuroglia) providechemicals that a neuron need tofunction properly.they also serve as the clean up crewby removing dead neurons and excessneurotransmitter substances.
Sensory Neuron Interneurons Motor Neurons
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.
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.
The human brain has threemajor components:1. the hindbrain;2. the midbrain; and3. the forebrain.
The hindbrain is made up ofseveral smaller structuressuch as the medulla, thepons, and the cerebellum.
The midbrain is composed of two parts:1. the reticular formation (a.k.a. reticular activating system or RAS); and2. 2. the brainstem.
The forebrain mainlyconsists the following:1. Cerebral cortex2. Limbic system3. Thalamus4. Hypothalamus5. Hippocampus6. Amygdala
1. Frontal lobe is largely responsible fora wide variety of human activities suchas: language attention reasoning planning goal setting self monitoring decision making judgment learning strategies interpreting others’ behaviour
The Endocrine System is a set of glands that regulate theactivities of certain organs by secreting hormones to thebloodstream.These hormones are chemical messengers that aremanufactured by the glands in the system. The endocrineglands include the pituitary, thyroid, parathyroid, andadrenal glands, the pancreas, ovaries, and testes.
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.
3. Thyroid Gland-locate inside the neck andsecretes a hormone called thyroxin that regulatesmetabolism (how fast the body burns its availableenergy).4. Pancreas-controls the blood sugar level bysecreting the insulin and glucagons.
5. Adrenal Glands-one on top of eachkidney, 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.