Systems of the Body PDF

Systems of the Body © 2020 MCGRAW-HILL EDUCATION LIMITED 1  Etiology and Correlates Graphic © 2020 McGraw-Hill Education 2 Limited The Nervous System Cell body – source of life of cell...

Systems of the Body © 2020 MCGRAW-HILL EDUCATION LIMITED 1  Etiology and Correlates Graphic © 2020 McGraw-Hill Education 2 Limited The Nervous System Cell body – source of life of cell Dendrites – branches on the cell bodies that act as receivers of messages from adjacent neurons. Axon – projection through which messages travel. Synaptic knobs: Tips of branches at end of axon. Sends messages to adjacent neurons. Synapse: Fluid filled gap between neurons. Message = electrical activity  The Nervous System Overview: Part I The nervous system (NS) is made up of the central nervous system and the peripheral nervous system The central nervous system (CNS) is made up of the brain and the spinal cord The peripheral nervous system (PNS) is made up of the somatic and autonomic nervous systems © 2020 McGraw-Hill Education Limited 4  Figure 2.1 Components of the nervous system © 2020 McGraw-Hill Education Limited 5  Figure 2.3 The Brain © 2020 McGraw-Hill Education Limited © 2020 McGraw-Hill Education Limited 6  Frontal Temporal Motor activity Hearing Higher level Vision intelligence Smell Planning Memory Problem solving Emotions Self-awareness Parietal Bodily sensations, Occipital Primary visual e.g., pain, heat Body movement area of the brain Each of the cerebral hemispheres receives sensory information from the opposite side of the brain, and also controls motor responses on the opposite side of the body (contralateral control) 15-8  The Nervous System Overview The Brain hindbrain: medulla – receives sensory information from heart pons – links hindbrain and midbrain cerebellum – coordinates voluntary muscle movement midbrain: major pathway for sensory and motor impulses moving between forebrain and hindbrain © 2020 McGraw-Hill Education Limited 9  The Nervous System Overview The Brain The forebrain has two main sections: diencephalon - thalamus – recognition and relay of sensory stimuli - hypothalamus – helps regulate heart and blood pressure telecephalon: - the two hemispheres (right and left) of our cerebral cortex © 2020 McGraw-Hill Education Limited 10 Limbic system: Amygdala: - detection of threat Hippocampus: - emotional memories Cingulate gyrus, Septum, areas of the Hypothalamus: - emotional functioning  The Nervous System Overview Neurotransmitters:  chemicals that regulate nervous system functioning Catecholamines:  epinephrine and norepinephrine - promote sympathetic NS activity - released during stressful times © 2020 McGraw-Hill Education Limited 12 Spinal cord Transmits messages from the brain to the other areas of the body. Efferent – away from the brain out to the body Produces muscle action Afferent – from the periphery to the brain Relays information from the sensory organs Central nervous system: the brain and spinal cord Peripheral nervous system: the neurons that convey messages to and from the rest of the body  The Nervous System The Peripheral Nervous System Autonomic Sympathetic (call to activity) Parasympathetic (call to rest) WILEY CANADA Somatic Nervous System Somatic: Involved in both sensory and motor functions of skin and muscles.  Autonomic Nervous System Controls what is generally involuntary, automatic activity Carries messages between the spinal cord and the smooth muscles of the internal organs Consists of the sympathetic and parasympathetic nervous systems.  Involved in mobilizing and expending energy in response to emergencies Sympath etic Fight or flight Nervous response System Also prepares the body for strenuous activity Parasympathetic Nervous System Restores equilibrium, regulates calming processes in the body Decreases arousal, slows breathing and heart rate, lowers heart rate and blood pressure, etc. WILEY CANADA  The Nervous System Disorders Disorders of the Nervous System: Epilepsy Parkinson’s disease Cerebral palsy Alzheimer’s disease Multiple sclerosis Huntington’s disease Paraplegia, quadriplegia © 2020 McGraw-Hill Education Limited 21  The Endocrine System Overview Complements the nervous system in controlling bodily activities. Regulated by the hypothalamus and pituitary gland. Communicates via chemical substances called hormones (e.g., adrenaline, cortisol) Hypothalam us © 2020 McGraw-Hill Education Limited 22 WILEY CANADA  Adrenal Gland Located on top of each kidney Release hormones in response to emergencies and stress cortisol: helps control swelling but continued high levels can lead to high blood pressure, ulcers, etc. epinephrine & norepinephrine (adrenalin and noradrenalin): produce bodily reactions for quick energy  Sympathetic Activation Events perceived to be Physiologi stressful create cal sympathetic nervous system arousal Systems in Triggers adrenal glands Stress Response to release catecholamines epinephrine and norepinephrine Blood pressure, heart rate increase (and many other changes) 25 © 2020 McGraw-Hill Education Limited  Figure 2.3 © 2020 McGraw-Hill Education Limited 26  Physiological Systems in Stress Response HPA Activation hypothalamic-pituitary-adrenocortical (HPA) axis pituitary gland releases hormone ACTH, triggering adrenal release of glucocorticoids, especially cortisol recurring activation compromises functioning, creating allostatic load hampers immune functioning 2020 McGraw-Hill Education Limited 27  Figure 2.7 © 2020 McGraw-Hill Education Limited 28  Thyroid Gland Located in the neck Produces hormone (thyroxin) that regulates activity level and growth. Hypothyroidism: Insufficient thyroid hormones (leads to low activity levels and weight gain) Hyperthyroidism: Over- secretion of thyroid hormones (leads to hyperactivity and weight loss, insomnia, tremors, etc.)  Pancreas Located below the stomach Regulates level of blood sugar by producing insulin which absorbs blood sugar. Important gland in diabetes mellitus  The Endocrine System Disorders Diabetes: Body cannot manufacture or properly use insulin - Type I: insulin-dependent diabetes - Type II: insufficient insulin or insensitivity to it © 2020 McGraw-Hill Education Limited 31  Mouth. Break down food particles, salivary gland action. Stomach. Initial protein digestion. Food is The liquefied and mixed. Digestive System Small intestine. Chemical break down, absorption. Large intestine. Water absorption and waste storage. WILEY CANADA Digestive System Enzymes: breaks down food substances Commands from the brain stem activates the production of saliva. Saliva contains enzymes that breakdown starches. Esophagus pushes food to the stomach using peristalsis.  Additional enzymes and bile continue the food breakdown. Digestiv Absorption occurs. e System Large intestine (mainly colon) continues absorption of water and passes the remaining waste to the rectum for excretion.  Peptic ulcers – open sores in the stomach or duodenum. Causes by excessive gastric Disorde juices and bacterial infection. rs of the Hepatitis – liver becomes Digestiv inflamed. e Cirrhosis – liver cells die and System are replaced by scar tissue. Caused by hepatitis and heavy alcohol consumption.  Body tissues need a constant supply of oxygen Mechanical action. (moving air in and out of the lungs) The Gas Exchange. (respiration) In the Respirat alveoli, CO2 (toxic gas) is ory eliminated and O2 enters the blood stream System Protective mechanisms. (sneezing, cough, mucous production) Impaired function. Asthma, pneumonia, bronchitis, emphysema, cancer WILEY CANADA Respirator y System Air enters the body through the nose and mouth. It travels past the larynx and down the trachea and bronchial tubes into the lung. Bronchial tubes divide into small branches called bronchioles, and then tiny sacs call alveoli.  Disorders of the Respiratory System Anoxia – shortage of Hyperventilation – Asphyxia – too little oxygen (occurs at deep rapid breaths oxygen and too very high altitudes). that reduce the much carbon dioxide Person looses amount of carbon (can occur in small judgment, pass into dioxide. breathing space). coma.  Cardiovascu lar System Transport system of the body. Consists of the heart, blood, and blood vessels Blood vessels consist of: Arteries that carry oxygenated (red) blood from the heart to the periphery and brain. Veins carries de- oxygenated (blue) blood back to the heart and  Heart Fist-sized muscle that circulates blood to and from the lungs to the body. Four chambers – atrium (right & left) and ventricles (right & left) Left side pumps oxygenated blood from lungs out to periphery and brain. Right side takes deoxygenated blood into the lungs. Blood Pressure (BP) Pressure of blood in the arteries. As the heart contracts and pushes blood into the arteries (systolic cardiac cycle) the BP rises. As the heart rests between beats and no blood is pumped (diastolic cardiac cycle) BP is at its lowest.  Cardiac output – volume of fluid pumped per minute. Blood pressure rises as cardiac output rises Blood volume – amount of blood in the system. Blood pressure rises as blood volume rises. Dynamics of Blood Peripheral resistance – ease with which blood can pass through Pressure the arteries (as resistance (BP) increases, BP increases) Elasticity – is the give and take in the arterial walls. As elasticity decreases BP increases. Viscosity – thickness of the blood. BP increases when the thickness of the blood increases. When arteries dilate (e.g., in heat) diastolic BP decreases. Blood BP increases when heart rate or Pressur cardiac output increases in response to activity, change in posture, while e (BP) talking, when under stress, temperature, etc. is Dynami BP follows a circadian (daily) rhythm such that it is lowest when c in deep sleep.  The Cardiovascular System Disorders: Part I Atherosclerosis: Caused by deposits of cholesterol and other substances on the arterial walls that form plaques and narrow the arteries It is in part a lifestyle disease because of its association with poor health habits © 2020 McGraw-Hill Education Limited 44  The Cardiovascular System Disorders: Part II Arteriosclerosis (hardening of the arteries) may also occur: Over time, plaques harden and blood vessels lose their elasticity which causes increases in blood pressure © 2020 McGraw-Hill Education Limited 45  Consequences of Atherosclerosis Angina pectoris – insufficient oxygen supply to the heart for its need and removal of waste products resulting in chest pain. Myocardial infarction (heart attack) – when there is a blockage of blood supply to an area of the heart cutting off oxygen supply to the tissue in the area and resulting in tissue death  Hypertension Permanently high blood pressure Systolic blood pressure >= 140 mmHg Diastolic blood pressure >= 90 mmHg Essential (primary) – no known physical cause (90- 95% of cases are of this type) Secondary hypertension – due to specific cause, e.g., adrenal tumor.  The Cardiovascular System Blood: Part I Adult body contains approximately 5 litres of blood Plasma is the fluid portion and it makes up about 55% of the volume The remaining 45% of the blood comprises substances such as red and white blood cells, proteins, electrolytes, platelets, oxygen, nutrients, and waste © 2020 McGraw-Hill Education Limited 48  The Cardiovascular System Blood: Part II Red blood cells primarily carry oxygen and nutrients White blood cells are primarily involved in immune functions Platelets are used in clotting blood and forming scabs Blood cells are manufactured in bone marrow Red cell White cell © 2020 McGraw-Hill Education Limited 49  Blood Two components: Formed elements Plasma Formed elements consist of three elements: Red blood cells Leukocytes (white blood cells) Platelets  Formed Elements – Red Blood Cells Most abundant cells Formed in bone marrow Contains hemoglobin – a protein that attaches to oxygen and transports it to the cells and tissue Anemia is when level of red blood cells is below normal  Disorders Related to Red Cell Production: Part I Anemia When insufficient red blood cells or hemoglobin impair transport of oxygen to cells Menstruating women may experience anemia due to loss of iron and may be helped by iron supplementation Anemia also occurs when bone marrow doesn’t producing enough red blood cells, potentially causing nervous system damage and chronic weakness © 2020 McGraw-Hill Education Limited 52  Disorders Related to Red Cell Production: Part II Sickle-Cell Anemia Sickle-cell anemia is a genetically transmitted inability to produce sufficient red blood cells and is found primarily in African, Middle Eastern, Caribbean, and South and Central Americans. © 2020 McGraw-Hill Education Limited 53  Disorders Related to Red Cell Production: Part III Sickle-Cell Anemia Cells are sickle-shaped rather than flattened spheres, believed to have developed to improve resistance to malaria but having potentially fatal consequences over the long term. © 2020 McGraw-Hill Education Limited 54 Leukocytes (white blood cells) Serve a protective function (e.g., destroys bacteria). Produced in bone marrow and various organs of the body. Leukemia is when there is an excessive production of white blood cells that crowd out plasma and red blood cells.  Disorders Related to White Cell Production Leukemia: disease of bone marrow – common form of cancer Leukopenia: deficiency of white blood cells – may accompany other diseases like TB, measles, and pneumonia Leukocytosis: excessive white blood cells – often response to infections like appendicitis and mononucleosis © 2020 McGraw-Hill Education Limited 56 Platelets Granular fragments that can clump together to prevent blood loss at site of cuts. Produced by bone marrow Hemophilia is when platelets don’t function properly to produce clotting and so if the person receives a cut could bleed excessively.  Disorders Related to Clotting Platelets Coronary and cerebral thromboses and embolus (detached clot that lodges in lung) can be fatal Platelet s © 2020 McGraw-Hill Education Limited 58  Plasma 55% of the blood is plasma Composed of 90% water and 10% plasma protein and other organic and inorganic substances. Other substances include hormones, enzymes, waste products, vitamins, sugars, fatty material etc.  Antigens are any substance (e.g., bacterial, viral, fungi) that can trigger an immune response. Bacterial – microorganisms in the environment. Grow rapidly and compete with our cells for nutrients. Can cause illness. The Fungi – organisms like mould and Immune yeast. Also, absorbs nutrients. System Protozoa – one-celled animals that live in water and insects. Drinking them can cause diseases. Viruses – proteins and nucleic acid. They take over the cell and generate their own genetic instructions.  The Immune System B cell Surveillance system of the body Impacts infection, allergies, cancer, and autoimmune diseases Primary function to distinguish between “self” and “foreign” and to attack what is considered foreign © 2020 McGraw-Hill Education Limited 62  Transplant success can by increased by: Using close genetic tissue match. Using medications that inhibit the immune system’s attack Immune on the foreign material. System Allergies are immune response to (normally) harmless substances. Allergens are substances that trigger an allergic response (e.g., pollen, cat dander)  The Immune System Infection: one path to illness is the invasion of microbes and their growth in the body Four means of infection: direct transmission indirect transmission biological transmission mechanical transmission © 2020 McGraw-Hill Education Limited 64  The Immune System The course of infection: incubation period period of nonspecific symptoms acute phase (disease is at its height) fatality or a period of decline during which invading organisms are expelled Infections may be localized, focal, or systemic © 2020 McGraw-Hill Education Limited 65  The Immune System Immunity: body’s resistance to injury from invading organisms develops naturally or artificially through vaccines occurs through either nonspecific immune mechanisms (fights any infection) or specific immune mechanisms (fights particular microorganisms) phagocytosis is when certain white blood cells ingest microbes © 2020 McGraw-Hill Education Limited 66  The Immune System Humoral immunity: mediated by B lymphocytes best against bacterial and viral infection Cell-mediated immunity: involving T lymphocytes best against fungi, parasites, foreign tissue, cancer © 2020 McGraw-Hill Education Limited 67 Organs of the Immune System Lymphatic and lymphoid organs Deploys lymphocytes Lymphocytes White blood cell that provides main defense against foreign material Produced by bone marrow Organs of the Immune System Lymph Nodes Bean-shaped spongy tissue Largest are in the neck, arm-pit, abdomen, and groin Filters to capture antigens (foreign material) and has compartments for lymphocytes. Lymph vessels Connects to lymph nodes and carries fluid called lymph into the blood  The Immune System Lymphatic organs: spleen – production of B and T cells; removes old red blood cells tonsils – filter microorganisms that get into respiratory tract thymus – helps T cells mature; produces hormone important for antibodies © 2020 McGraw-Hill Education Limited 70  Organs of the Immune System Spleen Upper left side of the abdomen Filters antigens that the lymph vessels put into the bloodstream Home base for white blood cells Removes worn out red blood cells  Soldiers of the Immune System Phagocytes Engulf and ingest antigens Two types: Macrophages – attach to tissue and stay there Monocytes – circulate in the blood Nonspecific immune processes  Specific Immune Processes Cell-mediated immunity Killer t-cells (CD8) – destroy foreign tissue, cancerous cells, cells invaded by antigens Memory t-cells – remember previous antigen in order to defend against subsequent invasions. Last a long time.  Cell-mediated immunity (continued) Specifi Delayed hypersensitivity t-cells – involved in delayed immune c reactions. Produce lymphokines that stimulate other t-cells to grow, Immun reproduce and attack. Helper t-cells (CD4 cells) – get e information of invasions and report to spleen and lymph nodes to stimulate Proces lymphocytes to attack. Suppressor t-cells – slow down or stop ses immune processes.  Immune System Antibody-mediated immunity Attacks antigens while they are still in the body fluids, before they have invaded cells Antibodies – proteins produced in the body in response to antigens. They combine chemically with antigens to overcome their toxic effects. B lymphocytes – secrete antibodies that protect body against bacterial Why Can’t We Fight Cancer? Some cancer cells release substances that suppress the immune response. Some antigens may be difficult for the immune system to recognize.  Immune function changes during the lifespan, increasing in childhood and decreasing in old age. Less Unhealthy lifestyles impair immune functioning Than Insufficient vitamin A or E Optimal decrease production of Defense lymphocytes and antibodies s Vitamin C in important in effectiveness of phagocytes High fat and cholesterol intake impair immune functioning Poor sleep impairs immune functioning  Stress and the Immune System Stress appears to suppress the immune response. Killer T-cells are lower during periods of high stress. Adrenaline and cortisol that are released during stress appear to increase suppressor T-cells, decrease helper T-cells, and decrease functioning of phagocytes and lymphocytes. Chemicals released by our nerves suppress immune functioning in nearby cells.  The Immune System Disorders related to the Immune System: AIDS Cancer Infectious disorders: - splenomegaly – infection of spleen - tonsillitis – inflammation impedes filter function - mononucleosis – enlargement in lymph system - lymphoma – tumor in lymphatic system © 2020 McGraw-Hill Education Limited 80 Diseases of the Immune System AIDS - kills by destroying helper T-cells CD4  The Immune System Autoimmunity Learning that inflammatory response that protects us in some circumstances is a cause or contributor to a great many of our chronic diseases Many diseases we believed had other causes are actually autoimmune in nature, in which the body attacks its own tissue © 2020 McGraw-Hill Education Limited 82