PHYSIOLOGICAL BASES OFPSYCHOLOGY

BIOPSYCHOLOGYZimbardo, Weber and Johnson (2000) defined it as the specialty in psychology that studies the interaction of biology, behavior and the environment.Feldman (2002) also refers it to Neuropsychology with which the importance of the nervous system in controlling behavior.

NEURONSThe basic structural unit of the nervous system is called NERVE CELL or NEURON.Approximation of trillion neurons throughout the nervous system.They are involved in the control of all bodily activities and behavior.

The Neuron

Parts of Neuron

Kinds of Neuron

Nerve ConductionWithin the NeuronDepolarization- An electrical process-70 mill voltsWhen the neuron is resting, not conducting nerve impulses, it is polarized.The cell is invaded by Na ions and the expulsion of K ions. The electric charge is gone. Depolarization occurs!Between NeuronsA chemical processWhen depolarization reaches the terminal buttons, neurotransmitters are released into the synapse.Either excite or inhibit the following neuron!Sending neuron-presynaptic neuronReceiving neuron- postsynaptic neuron.

Parts of the Brain:Frontal Lobe (Forebrain)

Four Types of Messengers: Neurotransmitters: released by terminal buttons of neurons and detected by receptors in the membrane of another cell a short distance away. Neuromodulators: released in large amounts from the terminal buttons, but diffused throughout part of the brain, affecting many neurons Hormones: produced by endocrine glands, released into extracellular fluid - stimulate cell receptors on membrane surface or deep within nuclei of cells, including neurons Pheromones: chemicals released into the environment through sweat, urine, or secretions of special glands. Most receptors in nose of other animals, but may also be detected in skin or other organs

Frontal LobeLocation- In the anterior most part of the brain (under the forehead)Function:Determines our consciousness of our environment.Determines how we initiate and respond to our environment.Daily decisions in our daily lives.Controls emotional responses and expressive language.Assigns meanings to the words we use.Involves word association.Controls memory for habits and motor activities.Emotional control center.

Parietal LobeLocation- Near the back and top of the head (Near the back and top of the head)Functions:Contains the location for visual attention.Contains the location for touch perception.Controls goal directed voluntary movements.Controls the manipulation of objects.Integrates different senses to allow for understanding a single concept.If not functioning correctly epileptic behavior can occur.

Illustration of the Occipital Lobe

Occipital LobeLocation- Located in the most posterior (Back of the head).Functions:Center of the visual perception center.Contains the primary visual cortex. Receives projections from the lateral geniculate nucleus of the thalamus.Numerous visual functions.

Temporal LobeLocation- at the side of the head and above the earsFunctions:Auditory sensation and perceptionOrganization and categorization of verbal materialLong term memoryPersonality and sexual behaviorOrganization of sensory inputThe brain has two temporal lobes, one on each side of the brain The two are interchangeable, so if one is damaged, the other is usually able to takeover the other's duties

Biological Foundations of PsychologyDivisions of the Brain

The Brain Stem(Medulla oblongata, the Midbrain, and the Pons.)Medulla OblongataLocation:Last part of the brain before reaching the spinal cord.Continuation of the spinal cordFunction:Many cranial nerves enter and leave the brain through the Medulla.Centers for cough, gag, swallow, and vomit.Cardiac Center.Respiratory Center.

Illustration of the Medulla Oblongata

MidbrainLocation:The Midbrain is located in the anterior most continuation of the brain stem that still maintains the tubular structure of the spinal cord (at the top of the brainstem)Functions:The top portion contains important nuclei for visual and auditory systemsIt is here that these pathways cross so that each half of the brain controls the opposite side of the body Deep within the brain stem is the reticular formation within which lies the basic life support systemsThe bottom portion contains nuclei for the cranial nerves that control eye movement and the lower portion of the brainThe Substania Nigra is found here. It is a large red nucleus involved in movement

PonsLocation:The Pons (meaning "bridge") lies above the medulla, and is so named because many axons cross sides within this region of the hindbrainFunctions:ArousalAssists in Controlling Autonomic FunctionsRelays Sensory Information Between the Cerebrum and CerebellumSleepFeatures of the pons are: a) basis pontis, b) middle cerebellar peduncle, and c) the superior cerebellar peduncleAll are linked to the cerebellum which sits on the posterior side of the pons. Damage to any of the structures would result in impaired coordination of movement and/or posture

CerebellumLocation:Two peach-size mounds of folded tissue at the base of the brain Overlies the ponsFunctions:The cerebellum ("little brain") has convolutions similar to those of cerebral cortex, only the folds are much smaller. Like the cerebrum, the cerebellum has an outer cortex, an inner white matter, and deep nuclei below the white matterNew skills are learned by trial and error and then coded into the cerebellar memoryCoordinates movement of muscles and joints by synthesizing data from the brain stem, the spinal cord, and another brain areas such as cerebral cortexThe cerebellum fine tunes our motor activity or movement

ThalamusLocation:The Thalamus is shaped like two footballs; each is located deep in the hemispheres of the forebrainA large mass of gray matter deeply situated in the forebrain. There is one on either side of the midlineFunctions:It relays to the cerebral cortex information received from diverse brain regions. Sort of a requisite 'last pit stop' for information going to cortexAxons from every sensory system (except olfaction) synapse here as the last relay site before the information reaches the cerebral cortexInformation from all sensory receptors except smell is processed in the thalamus before being sent to the cerebral cortex

HypothalamusLocation:The hypothalamus is a midline, structure, shaped like a funnel below the thalamusIt connects to the pituitary glandFunctions:The hypothalamus has many regulating functionsThe autonomic nervous system, emotions and behavior, body temperature, hunger, thirst, sleep-waking cyclesControls the release of hormones under its control: growth, prolactin, thyroid, corticotropin, and gonadotropinsRegulation of sex hormones, blood pressure, body temperature, water balance, respiration, and food intake, while it also plays a role in regulating complex moods, such as anger, placidity, and fatigue.

HippocampusLocation:The Hippocampus is tucked out of sight on the medial side of the temporal lobeIts shape resembles that of a 'seahorse'Functions:Stores and processes memoriesHelps find memoriesAffects emotionsThe hippocampus helps to encode memories, and then helps to find them when you want to remember somethingMain relay station that determines whether a new memory should go into long-term storage or be deleted after its short-term usefulness is over

Illustration of Hippocampus

Basal GangliaLocation- The basal ganglia surrounds the thalamus and is enclosed by the cerebral cortex and cerebral white matter.The name includes: caudate, putamen, nucleus accumbens, globus pallidus, substantia nigra, subthalamic nucleus Functions:Controls voluntary movements and establishing postures. Controls voluntary limb movement, eye movement, and cognition.Lesions in specific nuclei tend to produce characteristic deficits. One well-known disorder is Parkinson's disease, which is the slow and steady loss of dopaminergic neurons in synapses.

ConclusionThe study of physiology has made possible for better understanding of human behavior and function, as well as, the function and behavior of other species we share our world with.