Physio+Psy+Module+4.pdf

Subject: Physiological Psychology Topic: Nervous System and Endocrine System NERVOUS SYSTEM It is a complex network of interconnected fibers. It is a system made up of the central nervous system, which consists of the brain and spinal cord, and the peripheral nervous system, which is made u...

Subject: Physiological Psychology Topic: Nervous System and Endocrine System NERVOUS SYSTEM It is a complex network of interconnected fibers. It is a system made up of the central nervous system, which consists of the brain and spinal cord, and the peripheral nervous system, which is made up of somatic nervous system and the autonomic nervous system. CENTRAL NERVOUS SYSTEM I. Brain - is the command center of the body. It receives sensory impulses from the peripheral nerve endings and sends motor impulses to the extremities and to internal organs to carry out movement. - the brain lies within the skull and is shaped like a mushroom. The brain consists of four principal parts: 1. the brain stem 2. the cerebrum/cerebral cortex 3. the cerebellum 4. the limbic system - the brain weighs approximately 1.3 to 1.4 kg. It has nerve cells called the neurons and supporting cells called the glia. - there are two types of matter in the brain: grey matter and white matter. Grey matter receives and stores impulses. Cell bodies of neurons and neuroglia are in the grey matter. White matter in the brain carries impulses to and from grey matter. It consists of the nerve fibers (axons). Brain Hemispheres: 1. The Hindbrain - it has three main parts: a. The Medulla - is responsible for the regulation of vital reflexes such as heart rate, blood pressure, and respiration though the *cranial nerves; sensory information about the levels of carbon dioxide and oxygen in the body also comes to this part. b. Pons - serves as a link between the hindbrain and the midbrain and also helps control respiration c. The Cerebellum - coordinates voluntary muscle movement, the maintenance of balance and equilibrium, and the maintenance of muscle tone and posture. *Cranial Nerves - control sensations from the head, muscle movements in the head, and much of the parasympathetic output of the organs. Table. The Cranial Nerves Page 1 of 7  Name Functions Olfactory Smell Optic Vision Oculomotor Control of the eye movements, pupil constriction Trochlear Control of the eye movements Trigeminal Skin sensations from most of the face; control of jaw muscles for chewing and swallowing Abducens Control of eye movements Facial Taste from the anterior two thirds of the tongue; control of facial expressions, crying, salivation, and dilation of the head’s blood vessels Statoacoustic Hearing, equilibrium Glossopharyngeal Taste and other sensations form throat and posterior third of the tongue; control of swallowing, salivation, throat movements during speech Vagus Sensations from neck and thorax; control of throat, esophagus, and larynx; parasympathetic nerves to stomach, intestines, and other organs Accessory Control of neck and shoulder movements Hypoglossal Control of muscles of the tongue 2. The Midbrain - is the major pathway for sensory and motor impulses moving between the forebrain and the hindbrain. It is also responsible for the coordination of visual and auditory reflexes. - major structures: tectum, tegmentum, superior colliculus, inferior colliculus, substantia nigra. 3. The Forebrain - includes the thalamus and the hypothalamus, and the cerebral cortex. a. Thalamus - is involved in the recognition of sensory stimuli and the relay of sensory impulses to the cerebral cortex. b. Hypothalamus - helps regulate cardiac functioning, blood pressure, respiration, water balance, and appetites, including hunger and sexual desire. c. Cerebral Cortex - the largest portion of the brain, involved in higher order intelligence, memory and personality; it consists of four lobes (frontal, occipital, parietal, and temporal) - each lobe has its own memory storage areas of association. d. Pituitary Gland - is an endocrine gland attached to the base of the hypothalamus by a stalk that contains neurons, blood vessels, and connective tissue. In response to the message form the hypothalamus, it releases hormones into the bloodstream, which carries them to other organs. e. Basal Ganglia - a group of subcortical structures lateral to the thalamus, include 3 major structures: caudate nucleus, putamen, and the globus pallidus. The basal ganglia have multiple subdivisions, each of which exchanges information with a different part of the cerebral cortex. The connections are more abundant with the frontal areas of the cortex, which are Page 2 of 7  responsible for planning sequences of behavior and for certain aspects of memory and emotional expression. f. Hippocampus - is a large structure between the thalamus and the cerebral cortex, mostly toward the posterior of the forebrain. It is critical for storing certain kinds of memories but not all. I. Spinal Cord - it communicates with the sense organs and muscles below the level of the head. - it is a segmented structure, and each segment has on each side both a sensory nerve and a motor nerve. - each segment sends sensory information to the brain and receives motor commands from the brain. - many neurons in the spinal cord send axons from the gray matter toward the brain or to other parts of the spinal cord through the white matter, which is composed mostly of myelinated axons. PERIPHERAL NERVOUS SYSTEM The Peripheral nervous system is made up of two parts: 1. Somatic nervous system - consists of peripheral nerve fibers that pick up sensory information or sensations from the peripheral or distant organs (those away from the brain like limbs) and carry them to the central nervous system. 2. Autonomic nervous system - controls the nerves of the inner organs of the body on which humans have no conscious control. This includes the heartbeat, digestion, breathing (except conscious breathing) etc. - regulation of the autonomic nervous system occurs via the sympathetic nervous system and the parasympathetic nervous system. Sympathetic Nervous System - prepares the body to respond to emergencies, to strong emotions such as anger or fear, and to strenuous activity. Parasympathetic Nervous System - controls the activities of organs under normal circumstances; it helps restore the body to a normal state. Disorders of the Nervous System 1. Epilepsy - a disease in central nervous system marked by seizures, which range from barely noticeable to violent convulsions accompanied by irregular breathing and loss of consciousness. 2. Parkinson’s Disease - marked by tremors, rigidity, and slowness of movement caused by progressive degeneration of the basal ganglia (a group of nuclei in the brain that control smooth motor coordination). 3. Cerebral Palsy - is a chronic, nonprogressive disorder marked by lack of muscle control; it stems from brain damage caused by an interruption in the brain’s oxygen supply, usually during childbirth. 4. Multiple Sclerosis - a degenerative disease that can cause paralysis, and occasionally, blindness, deafness, and mental deterioration; early symptoms include numbness, double vision, dragging of the feet, loss of bladder or bowel control, speech difficulties, and extreme fatigue. 5. Huntington’s Disease - a hereditary disorder of the central nervous system characterized by chronic physical and mental deterioration; symptoms include muscle spasms, loss of motor abilities, personality changes, and other signs of mental disintegration. Page 3 of 7 6. Polio - it is a highly infectious viral disease that affects mostly young children; it attacks the spinal nerves and destroys the cell bodies of motor neurons so that motor impulses cannot be carried from the spinal cord outward to the peripheral nerves or muscles. 7. Paraplegia and Quadriplegia - paralysis of the body resulted from injury in the spinal cord. 8. Dementia - is a serious loss of cognitive ability beyond what might be expected from normal aging. ENDOCRINE SYSTEM The endocrine system complements the nervous system in controlling bodily activities. It is made up of a number of ductless glands that secrete hormones into the blood, stimulating changes in target organs. It is regulated by the hypothalamus and pituitary gland. Hormones - are the body's chemical messengers and are part of the endocrine system. Endocrine glands make hormones, which travel through the bloodstream to tissues and organs, and control most of our body's major systems. - are secreted from the glands of the endocrine system, they are specific in that each hormone causes a response in a specific target organ or group of cells, rather than on the body as a whole. Endocrine hormones are secreted via a duct into the blood and usually effect a distant organ or tissue. Endocrine hormones are secreted within the tissue (rather than via a duct) and enter the blood stream via capillaries. - they regulate homeostasis and the body’s responses to external and internal stimuli and also control tissue development, morphogenesis, and reproduction. - like neural impulses, endocrine secretions may act either to stimulate or inhibit a particular function; unlike neural impulses, they are often have metabotropic effect. Hormones can be grouped into three main types: 1. Amines - these are simple molecules. - member of a family of nitrogen-containing organic compounds that is derived, either in principle or in practice, from ammonia (NH3). - naturally occuring amines are the catecholamine neurotransmitters (i.e., dopamine, epinephrine, and norepinephrine); and a local chemical mediator, histamine, that occurs in most animal tissues. 2. Proteins and Peptides - are made from chains of amino acids. - Peptide hormones are hydrophylic and lipophobic (fat-hating) – meaning they cannot freely cross the plasma membrane - They bind to receptors on the surface of the cell, which are typically coupled to internally anchored proteins (e.g. G proteins) - The use of second messengers enables the amplification of the initial signal (as more molecules are activated) - Peptide hormones include insulin, glucagon, leptin, ADH and oxytocin 3. Steroids - which are derived from cholesterol. - Steroid hormones are lipophilic (fat-loving) – meaning they can freely diffuse across the plasma membrane of a cell - They bind to receptors in either the cytoplasm or nucleus of the target cell, to form an active receptor-hormone complex - This activated complex will move into the nucleus and bind directly to DNA, acting as a transcription factor for gene expression Page 4 of 7  - Examples of steroid hormones include those produced by the gonads (i.e. estrogen, progesterone and testosterone) Pituitary Gland - is located at the base of the brain; it has two lobes: a. Posterior Pituitary Lobe - produces oxytocin (the bonding molecule), which controls contractions during labor and lactation and is also involved in social affiliation, and vasopressin, or antidiuretic hormone (ADH), which controls the water-absorbing ability of the kidneys, among other functions. b. Anterior Pituitary Lobe - secretes hormones responsible for growth: 1. Somatotropic hormone (STH) - regulates bone, muscle, and other organ development. 2. Gonadotropic hormone - controls the growth, development, and secretions of the gonads 3. Thyrotropic hormone (TSH) - controls the growth, development, and secretion of the thyroid gland 4. Adrenocorticotropic hormone (ACTH) - controls the growth and secretions of the cortex region of the adrenal glands. Hypothalamus - This organ connects endocrine system with nervous system. Its main job is to tell your pituitary gland to start or stop making hormones. Endorphin - (pain-killing molecule) are produced by hypothalamus and pituitary gland during streneous physical exertion, sexual intercourse and orgasm. Adrenal Gland - are small glands located on top of each of the kidneys. - each adrenal gland consists of an adrenal medulla and an adrenal cortex. Epinephrine - hormone that is secreted mainly by the medulla of the adrenal glands and that functions primarily to increase cardiac output and to raise glucose levels in the blood. Norepinephrine - is a chemical released from the sympathetic nervous system in response to stress. It is classified as a neurotransmitter, a chemical that is released from neurons. Because the release of norepinephrine affects other organs of the body, it is also referred to as a stress hormone. - the chemical classification of norepinephrine is Catecholamines. - the release of this hormone prompts important bodily changes such as increased heart rate, dilated heart capillaries, constricted blood vessels, increased blood pressure. Thyroid Gland - This gland makes thyroid hormones, which controls metabolism. - secretes three main hormones: 1. Thyroxine contains iodine which is essential for the body's normal growth, and metabolism. Thyroxine helps control body size, regulating not only the growth of tissues but also the differentiation or specialisation of tissues. 2. Triiodothyronine has similar functions to thyroxine. 3. Calcitonin causes a decrease in the concentration of calcium in the blood. Calcitonin works with secretions from the parathyroid glands to maintain the balance of calcium necessary for the body to function. Parathyroid Gland - This is a set of four small glands behind the thyroid. They are important for bone health. The glands control levels of calcium and phosphorus. Page 5 of 7 Thymus Gland - This gland makes white blood cells called T-lymphocytes that fight infection and are crucial as a child's immune system develops. The thymus starts to shrink after puberty. Pineal Gland - This gland makes a chemical called melatonin. It helps the body get ready to go to sleep. Pancreas - it is part of both digestive and endocrine systems. It makes digestive enzymes that break down food. It also makes the hormones insulin and glucagon. These help ensure the right amount of sugar in the bloodstream and ells. *Insulin - a hormone produced in the pancreas by the islets of Langerhans that regulates the amount of glucose in the blood. *Glucagon - a hormone formed in the pancreas that promotes the breakdown of glycogen to glucose in the liver. Testicles - are a pair of sperm-producing organs that excrete hormones necessary for proper physical development in boys. *Testosterone - a hormone that is vital to the normal development of male secondary sexual characteristics. Ovaries - they maintain the health of the female reproductive system and fertility. *Estrogen - is instrumental in breast development, fat distribution in the hips, legs, and breasts, and the development of reproductive organs. *Progesterone - prepares the endometrium for implantation and later by the placenta during pregnancy to prevent rejection of the developing embryo. Diorders Involving the Endocrine System Diabetes - is a chronic endocrine disorder in which the body is not able to manufacture or properly use insulin. - it is one of the most common chronic illness and one of the leading causes of death. - patients have high rates of coronary heart disease, and is the leading cause of blindness among adults. - it can also produce nervous system damage, leading to pain and loss of sensation. - people with diabetes have a considerably shortened life expectancy. Forms of Diabetes: a. Type I Diabetes - is a severe disorder that typically arises in late childhood or early adolescence - partly genetic in nature - is an autoimmune disorder, possibly precipitated by an earlier viral infection. - the immune system falsely identifies cells in the islets of Langerhans in the pancreas as invaders and destroys those cells, compromising or eliminating their ability to produce insulin. - blood sugar levels can get dangerously high. b. Type II Diabetes - typically occurs after age of 40, is the more common form. - insulin may be produced by the body, but there may not be enough of it, or the body may not be sensitive to it. Page 6 of 7  - it is heavily a disease of lifestyle, and risk factors include obesity and stress, among other factors. Biological Psychology Page 7 of 7