Physiological Bases of Behavior (1).pdf

Physiological Bases of Behavior Nervou s https://www.youtube.com/watch?v=W4N- 7AlzK7s&list=PL8dPuuaLjXtOPRKzVLY0jJY- uHOH9KVU6&t=138s  The Nervous System is composed of: Glial Cells  Are responsible for the removal of dead neurons and waste products from the nervous sys...

Physiological Bases of Behavior Nervou s https://www.youtube.com/watch?v=W4N- 7AlzK7s&list=PL8dPuuaLjXtOPRKzVLY0jJY- uHOH9KVU6&t=138s  The Nervous System is composed of: Glial Cells  Are responsible for the removal of dead neurons and waste products from the nervous system, nourish and insulate neurons, form myelin, and play a role in neural transmission of messages. Dendrites  Are root like structures, attached to the cell body of a neuron, that receive impulses, or incoming messages, from other neurons. Axon  A long, thin part of a neuron that transmits impulses to other neurons form bulb-shaped structures called axon terminals or terminal buttons. Myelin  A fatty substance that encases and insulates axons, facilitating transmission of neural impulses. Neurons  are specialized cells of the nervous system that conduct impulses.  Neurons receive and transmit messages.  We are born with more than 100 billion neurons, most of which are in the brain. NEURONS: INTO THE FABULOUS FOREST  Afferent and Efferent Neurons Afferent Neurons  Neurons that transmit messages from sensory receptors to the spinal cord and brain  also called sensory neurons. Efferent Neurons  Neurons that transmit messages from the brain or spinal cord to muscles and glands  also called motor neurons.  THE NEURAL IMPULSE “THE BODY ELECTRIC”  Discovered in the 18th century, when the Italian physiologist Luigi Galvani (1737 – 1798) conducted a shocking experiment in a rainstorm. Galvani and his wife were out on the porch connecting lightning rods to the heads of dissected frogs whose legs were connected by wires to a well of water. When lightning blazed above, the frogs’ muscles contracted.  Neural Impulses are electrochemical discharge of a nerve cell or neuron.  ELECTROCHEMICAL VOYAGE The process of by which neural impulses travel is electrochemical. Chemical changes take place within neurons that cause an electrical charge to be transmitted along their lengths. Polarize To ready a neuron for firing by creating an internal negative charge in relation to the body fluid outside the cell membrane Resting Potential The electrical potential across the neural membrane when it is not responding to other neurons Depolarized To reduce the resting potential of a cell membrane from about 70 millivolts toward zero Action Potential The electrical impulse that provides the basis for the conduction of a neural impulse along an axon of neuron.  Synapse A junction between the axon terminals of one neuron and the dendrites or cell body of another neuron A synapse consists of an axon terminal from the transmitting neuron, a dendrite, or the body of a receiving neuron, and a fluid-filled gap between the two that is called the synaptic cleft REFLEXES  REFLEXES  inborn, stereotyped behavior patterns that have apparently evolved because they help individuals adapt to the environment even before they can understand and purposefully manipulate the environment Spinal cord  a column of nerves within the spine that transmits messages from sensory receptors to the brain and from the brain to muscles and glands throughout the body Spinal reflex  a simple, unlearned response to a stimulus that may involve only two neurons Gray matter  grayish neurons and neural segments that are involved in spinal reflexes White matter  axon bundles that carry messages to and from the brain  Neurotransmitters Are chemical substances involved in the transmission of neural impulses from one neuron to another. Receptor Site A location on a dendrite of a receiving neuron tailored to receive a neurotransmitter. Acetylcholine (ACh) A neurotransmitter that controls muscle contraction Hippocampus A structure of the brain that is involved in memory formation. Dopamine A neurotransmitter that affects the ability to perceive pleasure, voluntary movement, and learning and memory; it is involved in Parkinson’s disease and appears to play a role in schizophrenia. Norepinephrine A neurotransmitter whose action is similar to that of the hormone epinephrine and that may play a role in depression. Serotonin A neurotransmitter involved in emotional arousal and sleep; deficiencies of serotonin have been linked to eating disorders, alcoholism, depression, aggression, and insomnia. Gamma-Aminobutyric acid (GABA) An inhibitory neurotransmitter that apparently helps calm anxiety. Endorphins Inhibitory neurotransmitters that occur naturally in the brain and in the bloodstream and are similar to the narcotic morphine in their functions and effects.  Laws Governing the Neuron FIRING: HOW MESSAGES VOYAGE FROM NEURON TO NEURON The conduction of the neural impulse along the length of a neuron is what meant by firing. When neurons fire, it releases neurotransmitters. Neurotransmitters are released by the axon terminal of a neuron. However, neurons will not fire unless the incoming messages combine to reach a certain strength, which is defined as the threshold at which a neuron will fire. All-or-none Principle The fact that a neuron fires an impulse of the same strength whenever its action potential is triggered. Refractory Period A phase following firing during which a neuron is less sensitive to messages from other neurons and will not fire. The Central Nervous System  THE CENTRAL NERVOUS SYSTEM The body’s central processing unit consists of the spinal cord and the brain Spinal cord  a column of nerves within the spine that transmits messages from sensory receptors to the brain and from the brain to muscles and glands throughout the body  THE BRAIN https://www.youtube.com/watch?v =vHrmiy4W9C0&list=PL8dPuuaLj XtOPRKzVLY0jJY- uHOH9KVU6&index=5  THE BRAIN Philosophers and scientists have wondered about the functions of the brain throughout history. Some engage in research that attempts to pinpoint exactly what happens in certain parts of the brain when we are listening to music or trying to remember someone’s face. We have learned that brain damage can impair consciousness, perception, memory, and abilities to make plans and decisions. In some cases, the loss of large portions of the brain may result in little loss of function. But the loss of smaller portions in certain locations can cause language problems, memory loss or death. Scientists learn more about brain through methods like experimentation, electroencephalography, and brain scans. A Voyage Through The Brain Medulla  An oblong are of the hind-brain involved in regulation of heartbeat, blood pressure, movement, and respiration Pons  A structure of the hindbrain involved in respiration, attention, and sleep and arousal. Cerebellum  A part of the hindbrain involved in muscle coordination and balance. Reticular Formation  A part of the brain involved in attention, sleep, and arousal. Thalamus  An area near the center of the brain involved in the relay of sensory information to the cortex and in functions of sleep and attention. Hypothalamus  A bundle of nuclei below the thalamus involved in body temperature, motivation and emotion. Limbic System  A group of structures involved in memory, motivation, and emotion that forms a fringe along the inner edge of the cerebrum. Amygdala  A part of a limbic system that apparently facilitates stereotypical aggressive responses. Cerebrum  The large mass of the fore-brain, which consists of two hemispheres. Cerebral Cortex  The wrinkled surface area (gray matter) of the cerebrum. Corpus Callosum  A thick fiber bundle that connects the hemispheres of the cortex. THE STRUCTURE OF THE CEREBRAL CORTEX The cerebral cortex has two hemispheres, left and right. Each of the hemispheres is divided into four lobes. Somatosensory Cortex The section of cortex in which sensory stimulation is projected, it lies just behind the central fissure in the parietal lobe. Motor Cotrex The section of cortex that lies in the frontal lobe, just across the central fissure from the sensory cortex; neural impulses in the motor cortex are linked to muscular responses throughout the body THINKING, LANGUAGE, AND THE CEREBRAL CORTEX LANGUAGE FUNCTIONS  In some ways, the left and right hemispheres of the brain duplicate each other’s functions. In other ways, they differ.  The left hemisphere contains language functions for nearly all right-handed people and for two out of three left-handed people Aphasia  A disruption in the ability to understand or produce language. Wernicke’s Aphasia  A language disorder characterized by difficulty comprehending the meaning of spoken language. Broca’s Aphasia  A language disorder characterized by slow, laborious speech  LEFT BRAIN, RIGHT BRAIN?  The hemispheres of the brain are involved in very different kinds of intellectual and emotional functions and responses  Left-brained people would be primarily logical and intellectual.  Right-brained people would be intuitive, creative and emotional. HANDEDNESS  We are usually labelled right-handed or left-handed on the basis of our handwriting preferences, yet some people write with one hand and pass a football with the other.  Being left-handed appears to provide a somewhat greater-than- average probability of language problems, such as dyslexia and stuttering, and health problems such as migraine headaches and allergies  But there may also be advantages to being left-handed. Left-handed people are more likely than right-handed people to be numbered among the ranks of gifted artists, musicians and mathematicians The Peripheral Nervous System  The Peripheral Nervous System  contains the somatic and autonomic systems. In turn, the autonomic nervous system has sympathetic and parasympathetic divisions and the somatic nervous system has afferent and efferent nerves Somatic Nervous System  The division of the peripheral nervous system that connects the central nervous system with sensory receptors, skeletal muscles, and the surface of the body. Autonomic Nervous System (ANS)  The division of the peripheral nervous system that regulates glands and activities such as heartbeat, respiration, digestion, and dilation of the pupils. Sympathetic Division  The branch of ANS that is most active during emotional responses, such as fear and anxiety, which spend the body’s reserves of energy. Parasympathetic Division  The branch of the ANS that is most active during processes (such as digestion) that restore the body’s reserves of energy.  The Endocrine System  The body has two types of glands: glands with ducts and glands without ducts.  A duct is a passageway that carries substances to specific locations. Saliva, sweat, tears and breast milk all reach their destinations through ducts.  A number of substances secreted by ductless glands have effects on behaviour and mental processes  The ductless glands make up the endocrine system and they release hormones into the bloodstream.  Hormones are then picked up by specific receptor sites and regulate growth, metabolism, and some forms of behavior.  Much hormonal action helps the body maintain steady states such as fluid levels, blood sugar levels, and so on.  The maintenance of steady states requires feedback of bodily information to glands. This type of system is referred to as negative feedback loop. When enough of a hormone has been secreted, the gland is signalled to stop. Endocrine System  The body’s system of ductless glands that secrete hormones and release them directly into the bloodstream. Hormones A substance secreted by an endocrine gland that regulates various body functions. THE PITUITARY AND THE HYPOTHALAMUS The pituitary gland and the hypothalamus work in close cooperation. The pituitary gland lies below the hypothalamus. Although the pituitary is only about the size of a pea, it is so central to the body’s functioning that it has been dubbed the “master gland.” The anterior (front) and posterior (back) lobes of the pituitary gland secrete hormones that regulate the functioning of many other glands. Growth hormone regulates the growth of muscles, bones, and glands. Pituitary Gland  The gland that secretes growth hormone, prolactin, antidiuretic hormone, and other hormones. THE PINEAL GLAND The pineal gland secretes the hormone melatonin, which helps regulate the sleep-wake cycle and may affect the onset of puberty. Melatonin may also be connected with aging, In addition, t appears that melatonin is a mild sedative, and some people use it as a sleeping pill Melatonin may be used to help people to adjust to jet lag  THE THYROID GLAND  Could be considered the body’s accelerator. It produces thyroxin, which affects the body’s metabolism.  Some people are overweight because of hypothyroidism, a condition that results from too little thyroxin.  Thyroxin deficiency in children can lead to cretinism, a condition characterized by stunted growth and mental retardation.  Adults who secrete too little thyroxin may feel tired and sluggish and may put on weight.  People who produce too much thyroxin may develop hyperthyroidism, which is characterized by excitability, insomnia, and weight loss. Metabolism  The rate at which the body uses oxygen and produces energy. THE ADRENAL GLANDS  The adrenal glands, located above the kidneys, have an outer layer, or cortex, and an inner core, or medulla.  The adrenal cortex is regulated by the pituitary hormone ACTH (adrenocorticotrophic hormone).  The adrenal cortex secretes hormones known as corticosteroids, or cortical steroids. These hormones regulate the heartbeat, increase resistance to stress, promote muscle development, and cause the liver to release stored sugar, making more energy available in emergencies, such as when you see another car veering toward your own.  Epinephrine and norepinephrine are secreted by the adrenal medulla. Epinephrine, also known as adrenaline, is manufactured exclusively by the adrenal glands, but norepinephrine (noradrenaline) is produced elsewhere in the body. (Norepinephrine acts as a neurotransmitter in the brain.) The sympathetic branch of the autonomic nervous system causes the adrenal medulla to release a mixture of epinephrine and norepinephrine that helps arouse the body to cope with threats and stress. THE TESTES AND THE OVARIES  The testes and ovaries also produce steroids, among them are testosterone and estrogen. (Testosterone is also produced in smaller amounts by the adrenal glands.)  About six weeks after conception, the male sex hormone testosterone causes the male’s sex organs to develop. In fact, if it were not for the secretion of testosterone at this time, we would all develop the external genital organs of females.  During puberty, testosterone stoke the growth of the muscle and bone and the development of primary and secondary sex characteristics.  Primary sex characteristics are directly involved in reproduction and include the increased size of the penis and the sperm-producing ability of the testes.  Secondary sex characteristics, such as the presence of a beard and a deeper voice, differentiate males from females but are not directly involved in reproduction.  The ovaries produce estrogen and progesterone as well as small amounts of testosterone. (Estrogen is also produced in smaller amounts by the adrenal glands.)  Estrogen fosters female reproductive capacity and secondary sex characteristics such as accumulation of fatty tissue in the breasts and hips.  Progesterone stimulates growth of the female reproductive organs and prepares the uterus to maintain pregnancy.