Biopsychology PDF

Introduction: How do you differ from a machine? We usually think of a machine as something made of metal, but really a machine is anything that converts one type of energy into another, such as converting gasoline into the operation of a car. In that sense, you don’t differ from a machine a...

Introduction: How do you differ from a machine? We usually think of a machine as something made of metal, but really a machine is anything that converts one type of energy into another, such as converting gasoline into the operation of a car. In that sense, you don’t differ from a machine at all, because you are a machine. Your body converts the energy in your food into all the actions of your body. Your brain is part of that machine, and one way to understand your thoughts and actions is to analyze how your brain works. Researchers examine the functions of different parts of the brain, just as someone might study a car by examining what each of the car’s parts does. We start with the individual cells that compose the nervous system. Studying a single cell doesn’t take us far toward understanding your behavior, any more than studying a single silicon chip explains a computer. Still, it’s a place to start, and it does shed light on a few matters of psychological interest. THE HUMAN NERVOUS SYSTEM The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body. The nervous system includes both the Central nervous system and Peripheral nervous system. NEURON Neurons, or nerve cells, carry out the functions of the nervous system by conducting nerve impulses. They are highly specialized and amitotic. This means that if a neuron is destroyed, it cannot be replaced because neurons do not go through mitosis. The image below illustrates the structure of a typical neuron.  Parts of the Neuron: Image online source: https://training.seer.cancer.gov/anatomy/nervous/tissue.html Neurons are the basic building blocks of the nervous system. These specialized cells are the information-processing units of the brain responsible for receiving and transmitting information. Neurons carry messages throughout the body, including sensory information from external stimuli and signals from the brain to different muscle groups in the body. In order to understand exactly how a neuron works, it is important to look at each individual part of the neuron (see the picture above). The unique structures of the neuron allow it to receive and transmit signals to other neurons as well as other types of cells.  SOMA (cell body) - contains the nucleus and serves as the center of nourishment which connects the dendrites to the axon. It is responsible for the life of the neuron. The cell body is the neuron’s core. The cell body carries genetic information, maintains the neuron’s structure, and provides energy to drive activities. Like other cell bodies, a neuron’s soma contains a nucleus and specialized organelles. It’s enclosed by a membrane which both protects it and allows it to interact with its immediate surroundings.  DENDRITES (Dendron- tree)– short fibers projecting from the cell body. It serves as an input zone, receive information from other neurons. They are described as cellulipetal because they receive activity from adjacent cells and conduct the neural impulses to the cell.  AXON – long extension at one side of the cell body that carries messages to other cells or muscles or glands. They are described as cellulifugal because they conduct neural impulses away from the cell body. Axons range up to more than a meter in length, as in the case of axons from your spinal cord to your feet.  NODES OF RANVIER  These are microscopic gaps found within myelinated axons. Their function is to speed up propagation of action potentials along the axon via saltatory conduction  MYELIN SHEATH – White fatty substance which insulates and protects axons and speeds up the conduction of information, It is the axon’s protective coating. It is an insulating material around the axon to prevent messages from short-circuiting one another.  Terminal buttons - small knobs found at the ends of the branches of an axon \  Synapse - small gaps, which serve as a juncture between the terminal buttons of neuron and dendrites  Glia (Glue) - The glial cells surround neurons and provide support for and insulation between them.10 glial is equivalent to 1 neuron \ Image online source: https://i0.wp.com/www.compoundchem.com/wp-content/uploads/2015/07/Chemical- Structures-of-Neurotransmitters-2015.png?ssl=1 For more information: Adrenaline Adrenaline, also known as epinephrine, is a hormone produced in high stress or exciting situations. It stimulates increased heart rate, contracts blood vessels, and dilates airways, to increase blood flow to the muscles & oxygen to the lungs. This leads to a physical boost, and heightened awareness. EpiPens, which are used to treat allergic reactions, work by injecting adrenaline. Noradrenaline Noradrenaline, also known as norepinephrine, is a neurotransmitter that affects attention & and responding actions in the brain. Alongside adrenaline, it is also involved in the ‘fight or flight’ response. Its effect in the body is to contract blood vessels to increase blood flow. Patients diagnosed with ADHD will often be prescribed drugs designed to help increase levels of noradrenaline in the brain. Dopamine Dopamine is associated with feelings of pleasure & satisfaction. It is also associated with addiction, movement, and motivation. The feelings of satisfaction caused by dopamine can become desired, and to satisfy this the person will repeat behaviours that lead to release of dopamine. These behaviours can be natural, as with eating and sex, or unnatural, as with drug addiction. Serotonin Serotonin is thought to be a contributor to feelings of well-being and happiness. It regulates the sleep cycle along with melatonin, and also regulates intestinal movements. Low levels of serotonin have been linked to depression, anxiety, and some mental disorders. Antidepressants work by increasing serotonin levels. Exercise and light levels can also both have positive effects on the levels of serotonin. GABA Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter of the brain; its role is to calm firing nerves in the central nervous system.Increased levels improve mental focus and relaxation, whilst low levels can cause anxiety, and have also been linked with epilepsy. GABA also contributes to motor control and vision. Drugs to treat epilepsy often act by increasing levels of GABA in the brain. Acetylcholine Acetylcholine, often shortened to ACh, is the principal neurotransmitter involved in thought, learning and memory. In the body, it is involved in activating muscle action. Damage to the acetylcholine producing areas of the brain has been linked with the memory deficits associated with Alzheimer’s disease. Acetylcholine is also associated with attention, and enhancement of sensory perception upon waking. Glutamate Glutamate is the most common neurotransmitter in the brain, and is involved in cognitive functions, such as learning and memory. It also regulates brain development and creation of nerve contacts. Glutamate is actually toxic to neurons in larger quantities, and if too much is present it can kill them; brain damage or strokes can lead to the creation of a harmful excess, killing brain cells. Endorphins Endorphins are a range of compounds, the biologically active section of which is shown above, formed from long chains of multiple amino acids. They are released in the brain during exercise, excitement, pain, and sexual activity, and produce a feeling of well-being or even euphoria. At least 20 types of endorphins have been identified in humans. Certain foods, such as chocolate & spicy foods, can also stimulate the release of endorphins. Kinds of Neuron According to Functions SENSORY/AFFERENT NEURONS – conduct impulses from sense organs toward the spinal cord and the brain. MOTOR/EFFERENT NEURONS – conduct impulses from the brain or spinal cord to muscles and the glands. INTERNEURONS – conduct impulses from a sensory neuron to a motor nerve cell. NERVE IMPULSE TRANSMISSION – a neuron manifests irritability or the ability to respond to a stimulus. A cation is a positively charged ion, with fewer electrons than protons, while an anion is negatively charged, with more electrons than protons. DIVISIONS OF THE NERVOUS SYSTEM  CENTRAL NERVOUS SYSTEM – made up of the brain and the spinal cord. BRAIN – regarded as the seat of consciousness and higher mental processes. It is the largest part of the nervous system. It is safely protected by the skull (cranium) and by several layers (meninges). The brain controls our thoughts, memory and speech, movement of the arms and legs, and the function of many organs within our body. It assembles the messages in a way that has meaning for us, and can store that information in our memory. SPINAL CORD – main pathway of sensory or afferent impulses to the brain as well as the motor or efferent impulses from the brain. It is regarded as the seat of reflex actions. The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the body, and from the afferent fibers of the sensory neurons to the sensory cortex. It is also a center for coordinating many reflexes and contains reflex arcs that can independently control reflexes. Image online source: https://www.wisegeek.com/what-is-ray-tracing.htm PARTS OF THE BRAIN Image Source: Sternberg R., 2017, Karin Stern Berg Cognitive Psychology 7th Edition Sternberg R., 2012, Karin Stern Berg Cognitive Psychology 6th Edition from Getty Images; Noel Hendrickson/Blend Images/Corbis; background: Ingram Publishing/Getty Images. STRUCTURES OF THE BRAIN 1. CENTRAL CORE – “old brain”; innermost structure of the brain just above the spinal cord. Components of the Central Core a. Medulla – base of the central core and continuous with the spinal cord. Functions: Manages heartbeat, waking, sleeping, swallowing, digestion, and breathing (including sneezing, coughing and hiccups). It contains the Reticular Activating System which is important for our consciousness. This is how it looks like:  Image online source: https://www.neuroscientificallychallenged.com/blog/know-your-brain-medulla- oblongata b. Pons – act as the transmitter of motor information permitting the coordination of muscles and the integration of movement between the right and left halves of the body. Functions: It relays station between parts of the brain by using its neural fibers. Other than the reticular activating system, it also contains some of nerves serving parts of the head and face. With this, it deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture. This is how it looks like: Image online source: https://www.neuroscientificallychallenged.com/blog/know-your-brain-pons c. Cerebellum – controls the bodily balance. Alcohol depresses the activity of the cerebellum leading to the unsteady movements of drunkenness. Functions: It is necessary in coordination of our voluntary movements, balance, and equilibrium. It is also necessary in procedure-induced memory. It coordinates different muscles which is important in motor learning. This is how it looks like: Image online source: http://www.cs.cmu.edu/afs/cs/academic/class/15883-f13/lectures/cerebellum- anatomy/?C=S;O=D d. Reticular Formation – a group of nerve cells found within and between the medulla and the pons. Functions: It arouses the body to prepare it for appropriate action; screens out background stimuli in order to allow a person to sleep undisturbed. This is how it looks like: Image online source: https://neupsykey.com/reticular-formation-and-limbic-system/ e. Thalamus – acts primarily as a relay station, mostly for messages concerning sensory information. Functions: Leads sensory information through their respective regions in the cortex for interpretation. Along with the reticular activating system, the thalamus allows one to be consciously aware of themselves which leads one to be in control of their existence. It also transmits messages from the cerebral cortex to the cerebellum and medulla. This is how it looks like: Image online source: https://www.news-medical.net/health/What-is-the-Thalamus.aspx f. Hypothalamus – its major function is to maintain homeostasis, a steady internal environment for the body Functions: It organizes behavior related to survival (fighting, fleeing, feeding, mating). It regulates behavior that is critical to the basic survival of the species – eating, drinking, sexual behavior, aggression and nurturance of spring. It is also associated with the operation of the endocrine system. As well as in stirring the pituitary gland in excreting necessary hormone  This is how it looks like: Image online source: https://www.news-medical.net/health/What-is-the-Thalamus.aspx 2. LIMBIC SYSTEM – lies in between the central core and the cerebral cortex. Functions: includes self-preservation, learning, memory, emotions and experience of pleasure. This is how it looks like: Image online source: https://teenbraintalk.wordpress.com/limbic-system/ 3. CEREBARAL CORTEX It is the outer layer of the cerebral hemispheres. It plays a vital role in our thinking and other mental processes. Each hemisphere contains four lobes. Areas within these lobes oversee all forms of conscious experience, including perception, emotion, thought, and planning, as well as many unconscious cognitive and emotional processes. It plays an extremely important role in human cognition. It enables us to think. Note: Because of cerebral cortex we can plan, coordinate thoughts and actions, perceive visual and sound patterns, and use language Image online source: https://www.pinterest.ph/pin/302093087475304768/?nic_v2=1a1Fl7RY8 LOBES OF THE BRAIN a. Frontal Lobes – front of the cortex, considered as the expressive part of the brain because they contain major motor and speech and reasoning centers. Functions:  Personality, behavior, emotions  Judgment, planning, problem solving  Speech: speaking and writing (Broca’s area)  Body movement (motor strip)  Intelligence, concentration, self awareness b. Parietal Lobes – behind the frontal lobes; have been called the receptive part because they contain the centers where incoming sensory impulses arrive. Functions:  Interprets language, words  Sense of touch, pain, temperature (sensory strip)  Interprets signals from vision, hearing, motor, sensory and memory  Spatial and visual perception  c. Temporal Lobes – lower part of the brain, which contain the auditory center, and below it the center for taste and smell. Function:  Interprets vision (color, light, movement) d. Occipital Lobes – lying at the back of the skull, contain the visual center. Functions:  Understanding language (Wernicke’s area)  Memory  Hearing  Sequencing and organization of information PERIPHERAL NERVOUS SYSTEM A. Somatic Nervous System – composed of the 12 pairs of cranial nerves and 31 pairs of spinal cord. Its function is to organize all voluntary movements. B. Autonomic Nervous System – concerned with the parts of the body that keep us alive – heart, blood vessels, glands, lungs, and other organs that function involuntarily without our awareness. 1. 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). 2. PARASYMPATHETIC – calms the body, bringing functions back to normal after an emergency has passed.  Image online source: https://biologydictionary.net/endocrine-system/ GLANDULAR SYSTEM GLANDS – are organs of the body that secrete a substance to be used in, or eliminated from, the body. 1. EXOCRINE GLANDS (duct glands) – they eliminate their secretions onto the surface through a duct, as for instance the tear, sweat, and salivary glands. They are expressions of emotions, since they manifest reactions to emotions. 2. ENDOCRINE GLANDS (ductless glands) – they discharge their secretions directly into the blood stream. The chemical substances secreted by the endocrine glands are called hormones, a term with a Greek root meaning ‘activators’. a. PITUITARY GLAND – is located at the base of the brain, near and regulated by the hypothalamus. It is called the “master gland” because it secretes a number of hormones that stimulate or inhibit the secretion of other glands. It secretes growth hormone, which has crucial role of controlling body growth. Over secretion leads to GIANTISM and under secretion cause DWARFISM. b. THYROID GLAND – is located at the base of the throat and near the Adam’s apple in males. It secretes hormones known as thyroxin which control basal metabolism.  An over secretion of this hormone leads to HYPERTHYROIDISM, which is characterized by increased metabolism: the individual becomes tense, overactive, and irritable. Since over secretion is most often caused by iodine deficiency, supplying the iodine (iodized salt) reduces the over secretion and solves the problem.  An under secretion of the hormone leads to HYPOTHYROIDISM which may cause arrested physical and mental development in children. In adults, hypothyroidism causes slowing or retardation of motor activities and speech. The individual becomes unduly fatigued, loses interest, lacks pep, and easily becomes depressed. c. ADRENAL GLANDS – are located at the back of the body above the kidneys.  Adrenal Cortex (external part) – secretes hormones collectively known as cortin. Under secretion of cortin leads to excessive fatigue, loss of appetite, and apathy. In men, the sexual potency is reduced and symptoms of feminization occur. In women, over secretion of cortin has masculinizing effect, inhibiting the female functions.  Adrenal Medulla (internal part) – secretes adrenaline. It is especially active in emotion. The adrenaline prepares the organism for the typical “fight or flight” condition: increase in muscular strength and resistance to fatigue. d. PANCREAS – secretes insulin, and is responsible for controlling the sugar level in the blood. When there is a low supply of insulin, blood sugar increases due to non- utilization of sugar by the cells and may cause diabetes. Too much insulin causes  the rapid utilization of blood sugar resulting in extreme weakness of the body, cold sweating and may cause the individual to collapse. e. GONADS (Sex Glands)  Testes – male gonads that secrete testosterone for the production of male secondary characteristics.  Ovaries – female gonads that secrete estrogen for the appearance of female secondary characteristics and progesterone for the thickening of the uterine wall in preparation for pregnancy and childbirth. Let’s Have a break by reading this article: The Anatomy of the Brain: The brain controls your thoughts, feelings, and physical movements By Heidi Moawad, MD Medically reviewed by Keri Peterson, MD on March 17, 2020 The brain has a number of functions, including motor function (controlling the body’s movements), coordination, sensory functions (being aware of sensations), hormone control, regulation of the heart and lungs, emotions, memory, behavior, and creativity. These functions often rely on each other and interact with each other. For example, you might experience an emotion based on something that you see and/or hear. Or you might try to solve a problem with the help of your memory. Messages travel very quickly between the different regions in the brain, which makes the interactions almost instantaneous. Functions of the brain include: Motor function: Motor function is initiated in an area at the back of the frontal lobe, the motor homunculus. This region controls movement on the opposite side of the body by sending messages through the internal capsule, to the brainstem, then to the spinal cord and finally to a spinal nerve through a pathway described as the corticospinal tract. Coordination and balance: Your body maintains balance and coordination through a number of pathways in the cerebral cortex, cerebellum, and brainstem. Sensation: The brain receives sensory messages through a pathway that travels from the nerves in the skin and organs to the spine, then to the brainstem, up through the thalamus and finally to an area of the parietal lobe called the sensory homunculus—directly behind the motor homunculus. Each hemisphere receives sensory input from the opposite side of the body. This pathway is called the spinothalamic tract. Vision: Your optic nerves in your eyes can detect whatever you see, sending messages through your optic tract (pathway) to your occipital lobes. The occipital lobes put those messages together so that you can perceive what you are seeing in the world around you. Taste and smell: Your olfactory nerve detects smell, while several of your cranial nerves work together to detect taste. These nerves send messages to your brain. The sensations of smell and taste often interact, as smell amplifies your experience of taste. Hearing: You can detect sounds when a series of vibrations in your ear stimulate your vestibulocochlear nerve. The message is sent to your brainstem and then to your temporal cortex so that you can make sense of the sounds that you hear. Language: Speaking and understanding language is a specialized brain function that involves several regions of your dominant hemisphere (the side of the brain opposite your dominant hand). The two major areas that control speech are Wernicke’s area, which controls the understanding of speech, and Broca’s area, which controls the fluency of your speech. Emotions and memory: Your amygdala and hippocampus play important roles in storing memory, as well as associating certain memories with emotion. Hormones: Your hypothalamus, pituitary gland, and medulla all respond to the conditions of your body—such as your temperature, carbon dioxide level, and hormone levels—by releasing hormones and other chemicals that help regulate your body’s functions. Emotions, such as fear, can also have an influence on these functions. Behavior and judgment: The frontal lobes control reasoning, planning, and maintaining social interactions. This area of the brain is also involved in judgment and in maintaining appropriate behavior. Analytical thinking: Mathematical problem solving is located in the dominant hemisphere. Often, this type of reasoning involves interaction with the decision-making regions of the frontal lobes. Creativity: There are many types of creativity, including the production of visual art, music, and creative writing. These skills can involve three-dimensional thinking, also described and visual- spatial skills. Creativity also involves analytical reasoning, and usually requires a balance between traditional ways of thinking (which occurs in the frontal lobes) and “thinking outside the box." Associated Conditions There are many conditions that can affect the brain. You may experience self-limited issues, such as the pain of a headache, or more lasting effects of brain disease, such as paralysis due to a stroke. The diagnosis of brain illnesses may be complex and can involve a variety of medical examinations and tests, including a physical examination, imaging tests, neuropsychological testing, electroencephalography (EEG) and/or lumbar puncture. Common conditions that involve the brain include: Headaches: Head pain can occur due to chronic migraines or tension headaches. You can also have a headache when you feel sleepy, stressed, or due to an infection like meningitis (an infection of the meninges). Traumatic brain injury: An injury to the head can cause damage such as bleeding in the brain, a skull fracture, a bruise in the brain, or, in severe cases, death. These injuries may cause vision loss, paralysis, or severe cognitive (thinking) problems. Concussion: Head trauma can cause issues like loss of consciousness, memory impairment, and mood changes. These problems may develop even in the absence of bleeding or a skull fracture. Often, symptoms of a concussion resolve over time, but recurrent head trauma can cause serious and persistent problems with brain function, described as chronic traumatic encephalopathy (CTE). Transient ischemic attack (TIA): A temporary interruption in the blood supply to the brain can cause the affected areas to temporarily lose function. This can happen due to a blood clot, usually coming from the heart or carotid arteries. If the interruption in blood flow resolves before permanent brain damage occurs, this is called a TIA. Generally, a TIA is considered a warning that a person is at risk of having a stroke, so a search for stroke causes is usually necessary—and stroke prevention often needs to be initiated. Stroke: A stroke is brain damage that occurs due to an interruption of blood flow to the brain. This can occur due to a blood clot (ischemic stroke) or a bleed in the brain (hemorrhagic stroke).There are a number of causes of ischemic and hemorrhagic stroke, including heart disease, hypertension, and brain aneurysms. Brain aneurysm: An aneurysm is an outpouching of a blood vessel. A brain aneurysm can cause symptoms due to pressure on nearby structures. An aneurysm can also bleed or rupture, causing a hemorrhage in the brain. Sometimes an aneurysm can be surgically repaired before it ruptures, preventing serious consequences. Dementia: Degenerative disease of the regions in the brain that control memory and behavior can cause a loss of independence. This can occur in several conditions, such as Alzheimer’s disease, Lewy body dementia, Pick’s disease, and vascular dementia (caused by having many small strokes). Multiple sclerosis (MS): This is a condition characterized by demyelination (loss of the protective fatty coating around nerves) in the brain and spine. MS can cause a variety of effects, such as vision loss, muscle weakness, and sensory changes. The disease course can be characterized by exacerbations and remissions, a progressive decline, or a combination of these processes. Parkinson’s disease: This condition is a progressive movement disorder that causes tremors of the body (especially the arms), stiffness of movements, and a slow, shuffling pattern of walking. There are treatments for this condition, but it is not curable. Epilepsy: Recurrent seizures can occur due to brain damage or congenital (from birth) epilepsy. These episodes may involve involuntary movements, diminished consciousness, or both. Seizures usually last for a few seconds at a time, but prolonged seizures (status epilepticus) can occur as well. Anti-epileptic medications can help prevent seizures, and some emergency anti- epileptic medications can be used to stop a seizure while it is happening. Meningitis or encephalitis: An infection or inflammation of the meninges (meningitis) or the brain (encephalitis) can cause symptoms such as a fever, stiff neck, headache, or seizures. With treatment, meningitis usually improves without lasting effects, but encephalitis can cause brain damage, with long-term neurological impairment. A primary brain tumor starts in the brain, and brain tumors from the body can metastasize (spread) to the brain as well. These tumors can cause symptoms that correlate to the affected area of the brain. Brain tumors also may cause swelling in the brain, and hydrocephalus (a disruption of the CSF flow in the ventricular system). Treatments include surgery, chemotherapy, and radiation therapy.