Biological Psychology: An Introduction PDF

BIO PSYCHOLOGY Biological psychology ✓is the study of the physiological, evolutionary, and developmental mechanisms of behavior and experience. ✓concerns brain functioning.  Biological Explanation of behavior Four Categories 1. Physiological Explanation ✓ It deals with the mac...

BIO PSYCHOLOGY Biological psychology ✓is the study of the physiological, evolutionary, and developmental mechanisms of behavior and experience. ✓concerns brain functioning.  Biological Explanation of behavior Four Categories 1. Physiological Explanation ✓ It deals with the machinery of the body Example: the chemical reactions that enable hormones to influence brain activity and the routes by which brain activity controls muscle contractions. 2. Ontogenetic Explanation ✓ comes from Greek word “roots” meaning the “origin (or genesis) of being”. ✓ describes how a structure or behavior develops, including the influences of genes, nutrition, experiences, and their interactions. Example: the ability to inhibit impulses develops gradually from infancy through the teenage years, reflecting gradual maturation of the frontal parts of the brain. 3. Evolutionary explanation ✓ reconstructs the evolutionary history of a structure or behavior. The characteristic features of an animal are almost always modifications of something found in ancestral species (Shubin, Tabin, & Carroll, 2009). Example: monkeys use tools occasionally, and humans evolved elaborations on those abilities that enable us to use tools even better  Evolutionary explanations also call attention to features left over from ancestors that serve little or no function in the descendants. Example: frightened people get “goose bumps”—erections of the hairs— especially on their arms and shoulders. Goose bumps are useless to humans because our shoulder and arm hairs are so short and usually covered by clothing. In most other mammals, how ever, hair erection makes a frightened animal look larger and more intimidating. 3. Functional explanation ✓ describes why a structure or behavior evolved as it did. Within a small, isolated population, a gene can spread by accident through a process called genetic drift. Example: a dominant male with many offspring spreads all his genes, including some that helped him become dominant and other genes that were neutral or possibly disadvantageous. However, a gene that is prevalent in a large population presumably provided some advantage—at least in the past, though not necessarily today.  A functional explanation identifies that advantage. Example: ✓ species have an appearance that matches their background A functional explanation is that camouflaged appearance makes the animal inconspicuous to predators. Some species use their behavior as part of the camouflage. Behavioral Explanation: Summary 1. Physiological Explanation relates the behavior to an activity of the brain or other organs. It correlates with the mechanics of the body. 2. Ontogenetic Explanation describes the development of a behavior or structure. It maps the influences of nutrition, genes, experiences and the interactions of these factors in producing behaviors.  Summary 3. Evolutionary Explanation This explanation looks at how behavior has evolved over time to enhance survival and reproduction. 4. Functional Explanation This explanation focuses on the purpose or function of behavior. The behavior arise as motivated by internal drives, external rewards, classical or operant conditioning and because of social function. Career Opportunities  PHYSIOLOGICAL BASIS OF BEHAVIOR  Physiological Psychology studies the body’s response systems and how they translate internal stimulation into action. The body has various mechanisms in responding to the environment which include the ff… ✓Receiving mechanisms ✓Connecting Mechanisms ✓Reacting Mechanisms  The Nervous System The major instrument of integration and coordination of the many activities regarding human behavior through conduction of messages and making connections to ensure the smooth operation of all parts of the body Roles of the Nervous System 1. Monitoring changes 2. Interpretation of Sensory input 3. Effects and responses 4. Mental Activity 5. Homeostasis 2 Organization of the Nervous System 1. Structural Classification A. CNS-contains the brain and spinal cord B. PNS- contains nerves that extend outside the brain and spinal cord 2 Organization of the Nervous System 2. Functional Classification a. Sensory/afferent division b. Somatic sensory fibers c. Visceral sensory fibers d. Motor/efferent division  2 Motor/Efferent division 1. Somatic nervous System – skeletal muscles 2. Autonomic nervous system – cardiac muscles a. sympathetic b. parasympathetic  Nervous Tissue 1.Supporting cells a. neuroglia- nerve glue b. Astrocytes- protect the cell from harmful substances c. Microglia- dispose dead brain cells and bacteria d. Ependymal cells – lines the central cavity to protect the CNS e. Oligodendrocytes – produce myelin sheath f. Schwann cells- forms myelin sheath around nerve fibers in the PNS g. Satellite cells- acts as protective cautioning cells  Nervous Tissue 2. Neurons/nerve cells ✓ transmit nerve impulses BASIC UNITS OF THE NERVOUS SYSTEM A.NEURON -basic functional unit of the nervous system Structures of A Neuron PARTS of a NEURON 1. cell body 2. dendrite 3. axon 4. synaptic terminals / buttons /axon terminal 5. myelin sheath 6. nodes of Ranvier  1. CELL BODY Serves as a center of nourishment Carries the genetic information that will determine the type of cell and acts to direct the cell’s functioning  2. DENDRITE Receives signals from the axons of other neurons and carry those signals to the cell body  3. AXON A neuron’s extending fiber that conducts impulses/messages away from the cell body and transmit them to other neurons to where communication occurs with other nerve cells  4. Myelin Sheath The protective coating of an axon that is made of fats and protein Serves as the conductor that makes the flow of impulses faster 5. AXON TERMINAL An array of small terminal buds at the end of the axon which will relay information out of the nerve cell to the dendrites of the other neuron  B. SYNAPSE The site where transmission of a nerve impulse/ information from one neuron to another occurs  C. NERVE A bundle of elongated axons belonging to hundreds and thousands or neurons  Kinds of Neurons According to their Functions 1. SENSORY / AFFERENT NEURONS – conducts/transmits impulses/messages from sense organs towards the spinal cord and brain sensory receptors > Stimulus > spinal cord> brain> association of neurons will decide how to respond >communicate with the motor efferent neurons > back to spinal cord> towards the muscles indicating what motion to perform.  Kinds of Neurons According to their Functions 2. MOTOR / EFFERENT NEURONS – conducts/transmits impulses/messages from the brain or spinal cord to the muscles and the glands  Kinds of Neurons According to their Functions 3. INTERNEURONS – conducts impulses from a sensory neuron to a motor nerve cell  THE MAJOR COMPONENTS OF THE NERVOUS SYSTEM ✓The Central Nervous System – composed of the brain and spinal cord ✓The Peripheral Nervous System - Composed of the somatic and the autonomic nervous system 1. CENTRAL NERVOUS SYSTEM o The brain – center of control of the body/ regarded as the seat of consciousness and higher mental processes / composed of 90% of neurons of the body / largest part of the nervous system o The spinal cord – the seat of reflex actions since it is the main pathway of sensory (afferent) and motor (efferent) impulses DIVISIONS OF THE BRAIN A. CENTRAL CORE (THE OLD BRAIN) – innermost structure of the brain just above the spinal cord 1. Brain Stem -medulla -pons -midbrain 2. Cerebellum – PARTS OF THE CENTRAL CORE 1. THE BRAINSTEM – connects the brain and spinal cord -composed of the pons, medulla oblongata and the midbrain (reticular activating system)  a. MEDULLA Lies just above the spinal cord and is the lowest part of the brain stem Connects the spinal cord to the brain and regulates some vital bodily functions such as heartbeat, blood circulation and respiration-also activities like talking, singing, swallowing, vomiting, sneezing, coughing, chewing  b. PONS Lies just above the medulla and in front of the cerebellum The bridge that connects other parts of the brain and maintains the integration and coordination of movement between the right and left side of the body  b. PONS Activities involving the pons are motor impulses that govern chewing; control of eyeball movement, secretion of saliva and tears, contraction of muscles in the face and impulses related to balance or equilibrium  c. MIDBRAIN Also known as the mesencephalon Lies superior to the pons and the smallest and least differentiated structure of the brainstem that contains both white and gray matter  2. CEREBELLUM Located in the hindbrain standing atop the brainstem that is about a size of a fist which contributes to a sense of balance and coordinates the muscles so that movement is smooth and precise Its main function is for motor coordination such as in the maintenance of posture and balance B. LIMBIC SYSTEM (The Animal Brain) –structures in this region are heavily involved in emotions (such as rage and fear), learning, memory and especially experience of pleasure - Appears to be primarily responsible for our emotional life, and has a lot to do with the formation of memories. -Controls some of the instinctive activities like feeding, attacking, fleeing from danger and mating Parts of the Limbic System 1. Thalamus 2. Hypothalamus 3. Amygdala 4. Hippocampus  THALAMUS Found at the center of the brain It is regarded as the relay center since all information coming from the lower parts of the brain are relayed to the thalamus which in turn transmits it to the different centers of the brain  HYPOTHALAMUS A small structure below the thalamus It is known to regulate visceral, endocrine and metabolic activities such as sexual behavior, body temperature, sleeping, eating, drinking, and emotional responses. maintains homeostasis (balance and normal internal bodily functioning)  AMYGDALA Situated within the temporal lobe and implicated in the production of memory, emotions (e.g first love, embarrassing moment and violent behavior-aggressiveness) Damage in this area will result to the difficulty to recognize happiness, sadness or disgust.  HIPPOCAMPUS Plays a crucial role in storage of memory, which includes the critical storage of fleeting memory/new events as lasting memory (storage of long term memory). If the hippocampus is damage, a person cannot build memories 3. CENTRAL CORTEX (The New Brain) Cerebral Hemisphere 1. Right Hemisphere – controls the sensory and motor activities in the left side of the body such as the left hand touch. More involve with the perceptual, visual, spatial, artistic, musical and sympathetic cortical activity with both perception and expression of affective content 2. Left Hemisphere -controls the sensory and motor activities in the right side of the body. Controls certain activities like skills in math, language, science, writing and logic. 3. CENTRAL CORTEX (The New Brain) Frontal Lobe – Verbal/speech/Broca’s Area/ expressive part of the brain because they contain major motor and speech and reasoning centers Parietal Lobes – receptive part of the brain because they contain the centers where incoming sensory impulses arrive (touch) Temporal Lobes – contains the auditory center and below it is the center for tastes and smell Occipital Lobes – contains the sense of sight PERIPHERAL NERVOUS SYSTEM - Consists of nerve fibers going to and from the central nervous system. - It lies outside the bony case of the skull and the spinal cord DIVISIONS OF THE PNS AUTONOMIC NS – Sympathetic NS – Parasympathetic NS SOMATIC NS – Sensory/Afferent Neurons – Interneurons / Association Neurons – Motor/Efferent Neurons  PERIPHERAL NERVOUS SYSTEM o Somatic NS – composed of 12 pairs of cranial nerves and 31 pairs of spinal nerves. Its main function is to organize voluntary movements o Autonomic NS – composed of the nerves that are not under voluntary control. It is concerned with the parts of the body that keeps us alive such as the heart, blood vessels, glands, lungs and other organs that function involuntarily without our awareness. The ANS plays a particularly crucial role during emergency situations and hence in all emotional contexts DIVISIONS OF THE ANS ▪ Sympathetic _ prepares the body to respond to stressful situations (increased heart rate, additional supply of adrenaline, faster breathing, dilation of the pupil of the eye etc) ▪ Parasympathetic _ calms the body, bringing functions back to normal after emergency has passed ▪ The parasympathetic and sympathetic NS work harmoniously together to regulate many functions of the body.  GLANDULAR SYSTEM ✓ GLANDS – organs of the body that secret a substance to be used in, or eliminated from, the body. o Exocrine Glands (Duct Gland)  – eliminate/secretes their secretions onto the surface of a duct  - E.g.: tear, sweat, and salivary glands o Endocrine Glands (ductless glands) o – discharge or secretes their secretions directly into the bloodstream o – the chemical substances secreted by the endocrine glands are called HORMONES PITUITARY GLAND  – located at the base of the brain, near and regulated by the hypothalamus  – secretes a number of hormones that stimulate or inhibit the secretion of other glands  – the master gland  – Made up of two parts: Anterior lobe and posterior lobe ANTERIOR LOBE ▪ SECRETES: SOMATOTROPIN HORMONE / GROWTH HORMONE that regulates the growth of an individual; over-secretion results to Giantism and Acromegaly, under-secretion result to Dwarfism. ▪ – ACTH (adrenocorticotropic hormone) that stimulates the adrenal cortex to produce the steroid hormones – goiter ▪ – TSH (Thyroid Stimulating Hormone) that stimulating the thyroid gland to produce its hormones; - prolactin that induces mammary gland development and milk secretion; - gonadotropic hormones that at puberty stimulate the secretion of gonads. POSTERIOR LOBE secretes: - ADH (antidiuretic hormone) which controls the rate of water excretion into the urine – OXYTOCIN which helps deliver milk from the glands of the breast to the nipple during sucking; it also causes the contraction of the muscles of the uterus that help in the delivery of the baby. THYROID GLAND  – located in the tissue of the neck around the windpipe  – produces a hormone known as thyroxin – this hormone controls the metabolic processes by which the energy is provided for vital functions and activities  – behavioral consequences of a malfunctioning of the thyroid are as follows: Under secretion of thyroxin leads to a slowdown in the metabolic processes and results in an arrested mental and physical growth. Over secretion leads to speeding up of the metabolism. Thus it makes an individual tense, irritable, and overactive. Insomnia is frequent. PARATHYROID GLANDS  – two pairs of small glands adjacent to the thyroid gland  – they secrete a hormone parathyroid that keeps the supply of calcium in the bloodstream high, and the supply of phosphorus low  – deficiency of this hormone leads to an over excitability of the neuromuscular mechanism which leads to a condition of tetanus (a spasm of the muscles).  ADRENAL GLANDS ▪ – located at the back of the body above the kidneys ▪ –has two major parts that secretes their own hormone o Adrenal cortex (external part)  – secretes hormones collectively known as cortin  – undersecretion of cortin leads to excessive fatigue, loss of appetite, and apathy  – In men, the sexual potency is reduced and symptoms of feminization occur (note the interdependence between the adrenal cortex and the goands)  – In women, oversecretion of cortin has a masculinizing effect, inhibiting the female functions o AdrenalMedulla (internal part)  – secretes the adrenaline – the adrenal medulla is especially active in emotion  – the concentration of adrenaline in the bloodstream is increased to as much as 20% - 40% under emotional stress  – the adrenaline prepares the organism for the typical “fight or flight” condition: increase in muscular strength and resistance to fatigue.  PANCREAS  – secretes insulin and is responsible for controlling the sugar level in the blood – when sugar level rises above a certain level, pancreatic secretion of insulin causes the liver to absorb and store the excessive amount  - When sugar level drops, the liver releases more of it in the form of glucose  – an undersecretion of insulin therefore causes a large amount of sugar to accumulate in the body, a condition known as diabetes.  NEUROTRANSMITTERS & THEIR MODE OF ACTION BY, DAMARIS BENNY DANIEL I Msc. ZOOLOGY INTRODUCTION  Neurotransmitters are chemical messengers that transmit signals from a neuron to a target cell across a synapse.  Target cell may be a neuron or some other kind of cell like a muscle or gland cell.  Necessary for rapid communication in synapse.  Neurotransmitters are packaged into synaptic vesicles - presynaptic side of a synapse. Illustration of the major elements in chemical synaptic transmission. TYPES OF NEUROTRANSMITTERS EXCITATORY INHIBITORY BOTH Glycine Acetylcholine Glutamate GABA Nor epinephrine Aspartate Serotonin Nitric oxide Dopamine ACETYLCHOLINE (ACh)  Acetylcholine was the first neurotransmitter to be discovered.  Isolated in 1921 by a German biologist named Otto Loewi.  Used by the Autonomic Nervous System, such as smooth muscles of the heart, as an inhibitory neurotransmitter.  Responsible for stimulation of muscles, including the muscles of the gastro-intestinal system.  Used everywhere in the brain.  Degeneration in the Hippocampus would lead to Alzheimer's Disease  plays a major role in the formation of memories, verbal and logical reasoning and concentration. DOPAMINE  Generally involved in regulatory motor activity, in mood, motivation and attention. Play a lot of different roles in the brain depending on their location. In the frontal cortex, it acts as a traffic officer by controlling the flow of information to the other areas of the brain  It plays a role in attention, problem solving and memory  Also play a role in things that gives pleasure  Schizophrenics have too much dopamine.  Patients with Parkinson's Disease have too little dopamine. Dopamine NOREPINEPHRINE (nor adrenaline)  Secreted by the adrenal gland. It is strongly associated with bringing our nervous systems into "high alert."  An excitatory neurotransmitter that helps to activate the sympathetic nervous system which is your fight or flight response to a stressor.  When released in the bloodstream, it increases our heart rate, blood pressure, releases glucose energystones and increase blood flow to the muscles.  play a role in attention, emotion, sleeping, dreaming and learning. Norepinephrine γ-AMINO BUTYRIC ACID (GABA)  GABA is the most important inhibitory neurotransmitter that help balance any neuron that might be over firing. This becomes especially helpful when it comes to anxiety or fear because the release of GABA helps to calm you down.  Play a role in vision and motor control  Present in high concentrations in the CNS, preventing the brain from becoming overexcited.  If GABA is lacking in certain parts  of the brain, epilepsy results. GABA SEROTONIN (5-HT)  Known as the happy hormone that is involved with mood, pain , control and digestion.  Regulates attention and other complex cognitive functions, such as sleep (dreaming), eating, mood, pain regulation.  Too little serotonin has been shown to lead to depression, anger control etc. GLUTAMATE  It the most commonly found excitatory neurotransmitter in the brain.  Glutamate is actually toxic to neurons and excess of it will till them  It is involved in most aspects of normal brain function including cognition, memory and learning. How to Stabilize the Hormones ALCOHOL & NEUROTRANSMITTERS  It binds directly to receptors for ACh, serotonin, GABA and glutamate.  It enhances the effects of the GABA, which is an inhibitory neurotransmitter. ◦ Enhancing an inhibitor make things sluggish. ◦ The neuron activity is diminished- sedative effects of alcohol.  Alcohol inhibits glutamate receptor function. ◦ This causes discoordination, slurred speech, staggering, memory disruption, and blackout.  Alcohol raises dopamine levels. ◦ This leads to excitement, pleasure and later addiction. NICOTINE & NEUROTRANSMITTERS  Nicotine imitates the action of ACh & binds to ACh receptor.  Like acetylcholine, nicotine leads to a burst of receptor activity.  Nicotine activates cholinergic neurons in many different regions throughout your brain simultaneously.  This stimulation leads to: ◦ Increased release of glutamate. ◦ Stimulation of cholinergic neurons promotes the release of dopamine. The production of dopamine causes feelings of reward and pleasure. DISEASES ASSOCIATED WITH NEUROTRANSMITTERS NEUROTRANSMITTER DISEASE  Acetylcholine  Alzheimer’s  Dopamine  Parkinson’s disease  Schizophrenia  GABA  Epilepsy  Serotonin  Migraines  ADD  Depression  Glutamate  Migraine  stroke Disorders Associated with the Neurotransmitters  Alzheimer’s disease  Depression  Alzheimer’s disease is a  Depression is believed to be neurodegenerative caused by a depletion of disorder characterized by norepinephrine, serotonin, learning and memory and dopamine in the central impairments. It is nervous system. Hence, associated with a lack of pharmacological treatment of acetylcholine in certain depression aims at increasing regions of the brain. the concentrations of these neurotransmitters in the central nervous system.  Schizophrenia  Parkinson’s disease  Schizophrenia, which is a  The destruction of the severe mental illness, has substantia nigra leads to the been shown to involve destruction of the only excessive amounts of central nervous system dopamine in the frontal lobes, source of dopamine. which leads to psychotic Dopamine depletion leads episodes in these patients. to uncontrollable muscle The drugs that block tremors seen in patients dopamine are used to help suffering from Parkinson's schizophrenic conditions. disease.  Epilepsy  Huntington’s disease  Some epileptic conditions  Besides epilepsy, a chronic are caused by the lack of reduction of GABA in the brain can inhibitory lead to Huntington’s disease. Even neurotransmitters, such as though this is an inherited disease GABA, or by the increase of related to abnormality in DNA, one excitatory of the products of such disordered neurotransmitters, such is DNA is the reduced ability of the glutamate. Depending on neurons to take up GABA. There is the cause of the seizures, the no cure for Huntington’s disease, treatment is aimed to either but we still can treat symptoms by increase GABA or decrease pharmacologically increasing the glutamate. amount of inhibitory neurotransmitters.  Myasthenia gravis  Myasthenia gravis is a rare chronic autoimmune disease characterized by the impairment of synaptic transmission of acetylcholine at neuromuscular junctions, leading to fatigue and muscular weakness without atrophy.  Myasthenia gravis results from circulating antibodies that block acetylcholine receptors at the postsynaptic neuromuscular junction. This inhibits the excitatory effects of acetylcholine on nicotinic receptors at neuromuscular junctions. CONCLUSION  The ability of nervous system to orchestrate complex behaviors, learn and remember depends on communication between vast no. of neurons.  Mediated by neurotransmitters.  They play an important role in control and coordination of body.  Many neurological diseases and mental disorders are due to improper functioning of neurotransmitters. REFERENCES  Knut Schmidt Nielsen, Animal Physiology – Adaptation and environment, 4th edition, Cambridge University Press, U.K  Kalat  Richard.W.Hill (1976) Animal Physiology, 2nd edition, Harper Collin’s Publishers, New York.  http://www.sciencedaily.com/releases/2011/12/111205 165907.htm  http://www.columbia.edu/cu/psychology/courses/1010 /mangels/neuro/transmission/transmission.html  http://www.chemistryexplained.com/NeNu/Neurotransmitters.html#b