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85 Cards in this Set
- Front
- Back
Respiration
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Physiological process by which oxygen moves into internal environment and carbon dioxide moves out
Oxygen is needed for aerobic respiration Carbon dioxide is produced by same The respiratory system works hand-in-hand with circulatory system for gas exchange/flow Also helps regulate acid/base balance System is “open” to the environment and thus open to chemicals and infectious agents |
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Airways: Large Surface Area
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Air enters through nose, moves through pharynx and larynx to trachea
Trachea branches into two bronchi Each bronchus branches into bronchioles Bronchioles end in alveoli where gas exchange |
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Speech Production
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Vocal cords stretch across laryngeal opening; opening between them is glottis
Position of cords is varied to create different sounds |
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Pressure Gradients
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Concentration gradients exist for both oxygen and carbon dioxide in the body; both have a tendency to diffuse down their pressure gradients
Gases enter and leave the body by diffusing down pressure gradients across respiratory membranes Hemoglobin aids in maintaining the gradient by pulling oxygen away from lungs Atmospheric pressure is the pressure exerted by the weight of the air on objects on Earth’s surface At sea level = 760mm Hg O2 is 21% of air; partial pressure is ~ 160mm Hg; partial pressure CO2 is 0.3mm Hg |
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When O2 is Scarce (Hypoxia)
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Altitude sickness
Humans are adapted to lower elevations where oxygen levels are relatively high At high altitude, hyperventilation leads to ion imbalances in cerebrospinal fluid; increased capillary permeability can cause edema Carbon monoxide poisoning CO binds to hemoglobin 200 times more tightly than oxygen does Even tiny amounts can tie up hemoglobin and prevent oxygen delivery; can be fatal |
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Breathing (Respiratory Cycle)
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Inhalation
Diaphragm flattens, external muscles contract, volume of thoracic cavity increases, lungs expand air flows down pressure gradient into lungs Exhalation Normal (passive): muscles relax, thoracic cavity recoils, lung volume decreases air flows down pressure gradient and out of lungs Active: muscles contract, decreasing thoracic cavity volume more than passive exhalation a greater volume of air must flow out to equalize intrapulmonary pressure with atmospheric pressure |
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Gas Exchange
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Occurs between blood in pulmonary capillaries and air in the alveoli
Respiratory membrane is extremely thin and allows rapid diffusion of gases |
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Gas Transport
Oxygen |
Most is carried bound to hemoglobin in red blood cells
Hemoglobin has a great affinity for oxygen when it is at high partial pressure (in pulmonary capillaries), lower affinity for oxygen in tissues, where partial pressure is low |
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Gas Transport
Carbon Dioxide |
Most is transported as bicarbonate, smaller amounts are transported dissolved in blood and bound to hemoglobin
Bicarbonate formation is enhanced by the action of carbonic anhydrase inside red blood cells |
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Breathing rhythm:
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Diaphragm and intercostal muscles under control of reticular formation; one cell cluster controls inspiration, the other expiration the resulting rhythm is fine tuned by centers in the brain stem
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Magnitude of breathing:
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Receptors in medulla detect H+ and signal increases in rate and depth of breathing; Carotid bodies and aortic bodies detect CO2, oxygen, and pH to also signal increase in rate of breathing
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Chemical controls
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Increase in CO2 causes smooth muscle of bronchioles to dilate; decrease in CO2 causes smooth muscle of bronchioles to constrict
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Bronchitis
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Irritation of the ciliated epithelium that lines the bronchiole walls
Air pollutants, smoking, or allergies can be the cause Chronic bronchitis scars and constricts airways |
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Emphysema:
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An irreversible breakdown in alveolar walls
May be genetic defect; Most often caused by smoking Lungs become inelastic |
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Asthma:
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Smooth muscle ringing bronchi contracts; mucus is produced by bronchial epithelium
Can be triggered by allergens; Result is reduced air flow |
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Apnea:
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Breathing stops and starts, more common as age
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Upper RT Infections
Bacterial Diseases |
Strep throat, rheumatic fever, scarlet fever, ear infections following throat infections, diphtheria
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Upper RT Infections
Viral Diseases |
Common cold (200+ different viruses can cause the common cold, including members of the adenovirus and rhinovirus groups), croup
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Lower RT Infections
Bacterial Diseases |
Bacterial pneumonias: pneumococcal (80%), primary atypical (walking) pneumonia, legionellosis, Q fever, psittacosis, chlamydial
Other bacterial diseases: pertussis, tuberculosis, inhalational anthrax |
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Lower RT Infections
Viral Diseases |
Influenza, RSV, SARS, Hantavirus
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Lower RT Infections
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Histoplasmosis, blastomycosis, coccidioidomycosis (3 of the 4 actual pathogenic fungal diseases)
PCP (occurs in 90% HIV patients) |
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Three Lines of Defense
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Barriers at body surfaces
Nonspecific responses Immune responses |
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Three Lines of Defense
Barriers at body surfaces |
Intact skin and mucous membranes
Lysozyme Normal bacterial flora Flushing effect and low pH of urine |
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Three Lines of Defense
Nonspecific responses |
Lymph nodes trap and kill pathogens
White blood cells attack a range of pathogens Inflammation Complement |
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Three Lines of Defense
Immune responses |
T cells and B cells to attack and kill pathogens or infected cells
Communication signals and chemical weapons (antibodies) |
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Acute Inflammation
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Nonspecific immune response to foreign invasion, tissue damage, or both; characterized by redness, swelling, warmth, and pain
Destroys invaders, removes debris, prepares area for healing Excess inflammation is a problem in some autoimmune diseases and some infections |
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Features of Immune Responses
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Self/non-self recognition
Recognition based on identification of “antigens” – “non-self” markers on foreign agents and altered body cells such as tumors Specificity Recognition of an antigen leads to rounds of cell division that form huge populations of lymphocytes Specialization of lymphocytes into effector and memory cells that have receptors for one kind of antigen Diversity Billions of different effector cells can be generated; effector cells engage and destroy invaders Memory Memory cells protect us from future recurrence of disease |
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Cells and Proteins
MHC markers |
identify “self” from “non-self”; all of your cells have 1 of 2 classes of MHC marker on their surfaces
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Cells and Proteins
Antigen-presenting cells |
process antigens and then present (in presence of MHC) to immune cells for recognition and destruction
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Cells and Proteins
T cells |
Helper T cells recognize Antigen-MHC presentation and stimulate further immune responses
Cytotoxic T cells and Natural Killer cells attack and destroy infected body cells, tumor cells and cells of organ transplants Suppressor T cells turn off immune responses |
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Cells and Proteins
B cells |
produce antibodies to “mark” antigens, invaders and cells for destruction
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Clonal Selection
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B cells and T cells have antigen receptors on their surfaces; each receptor is unique for a given antigen
Receptors are produced via genetic recombination B cells produce antibodies with specific variable regions to recognize antigens; T cells have TCRs (T-Cell Receptors) Since each B cell and T cell is different; once recognition of an antigen occurs, the selected cell must be mass produced to allow for an immune response |
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Immunological Memory
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During a primary immune response, large numbers of effector cells are produced along with memory cells
Only the effector cells participate in the response to clear the invader Memory cells are held back During subsequent exposre to the SAME antigen, memory cells specific for that antigen are quickly activated to divide and clear the invader If the antigen is different, no recognition occurs |
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Antibody-Mediated Responses
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Carried out by B cells
Targets are intracellular pathogens and toxins Antibodies bind to target and mark it for destruction by phagocytes and complement 5 types of antibodies made IgM = 1st Ab produced during response IgG = circulating; complement, neutralization IgA = secreted in mucus membranes; neutralization IgD = T cell activation IgE = allergic reactions |
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Cell-Mediated Responses
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Carried out by T cells
Stimulated by antigen-presenting macrophages Main target is antigen-presenting body cells (cells with intracellular pathogens) or tumor cells Kill by releasing chemicals that cause apoptosis (programmed cell death) |
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Organ Transplants
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Donor and recipient must share at least 75% of their MHC markers in order to be “compatible”
After surgery, recipient receives drugs that suppress the immune system Because of immune system suppression, recipient must take large doses of antibiotics to prevent infections One of the major problems with organ transplantation today is a lack of organs Increase in “living” donations and donations between strangers can lead to ethical questions |
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Immunology and Medicine
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Immunization
Active immunization: Antigen-containing material is injected to confer long-lasting immunity Passive immunization: Purified antibody is injected; protection is short lived Diagnostics Monoclonal antibodies are made by cells cloned from a single antibody-producing B cell; can be used to specifically bind to and identify antigens in patients Immune Therapies Interferons can be used to treat viral infections |
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Immune Disorders
Allergies |
Immune reaction to a harmless substance
Genetic predisposition: IgE responds to antigen by binding cells which then secrete histamine to cause symptoms Severe reactions can lead to life-threatening anaphylactic shock (wasp or bee venoms usually cause this, not pollen) |
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Immune Disorders
Autoimmune Disorders |
Immune system makes antibodies against self antigens
Rheumatoid arthritis; Type I diabetes; Lupus |
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Immune Disorders
Autoimmune Disorders |
Immune system is weak or lacking
SCID: body’s ability to make lymphocytes is impaired or nonexistent; high vulnerability to infection HIV/AIDS: destruction of T cells + immune function |
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Microbial Evasion
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The immune system is a powerful protector, but microbes have many ways of evading clearance
Infection of immune cells themselves, or in other “privileged” sites (effectively hide) Destruction of immune cells Suppression of immune responses Molecular mimicry Antigenic variation Antigenic variation is of paramount threat Influenza has different strains Antigenic shift (subtle change) Antigenic drift (dramatic change) |
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Neurons
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Basic units of communication in nearly all nervous systems: Monitor information in and around the body and issue commands for responsive actions
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Sensory neurons
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(collect and relay info to spinal cord and brain)
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Interneurons
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(receive and process sensory input from the sensory neurons)
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Motor neurons
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(receive signals from interneurons to effect responses)
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Neuroglia
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A variety of cells that metabolically assist, structurally support, and protect the neurons
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Pumping and Leaking
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Movement is balanced outside vs. inside; movement itself, however, through active pumping of ions or leaking of ions, is essential to the formation of the action potential, to its propagation, and to its eventual silencing
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Action potentials/“all or nothing” responses
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All action potentials are the same size
If stimulation is below threshold level, no action potential occurs If it is above threshold level, cell is always depolarized to the same level Once potential spikes, gated sodium channels close, potassium channels open Influx of sodium stops, potassium flows out Original voltage difference is reestablished |
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Chemical Synapses
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Action potentials can trigger the release of neurotransmitters, signaling molecules that diffuse across chemical synapses
Gaps between the terminal ending of an axon and the input zone of another cell Gaps can be between neurons or between a neuron and muscle or gland cell |
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Synaptic Transmission
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Action potential in axon ending of presynaptic cell causes voltage-gated calcium channels to open
Flow of calcium into presynaptic cell causes release of neurotransmitter into synaptic cleft Examples: acetylcholine, serotonin Neuromodulators can magnify or impede the effect of a neurotransmitter Neurotransmitter diffuses across cleft and binds to receptors on membrane of postsynaptic cell Binding of neurotransmitter to receptors opens ion channels in the membrane of postsynaptic cell Receiving cell can either be excited or inhibited Signals must eventually be turned off |
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Information flow
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Sensory nerves relay information to the spinal cord where they form chemical synapses with interneurons. Interneurons within the spinal cord and brain integrate signals; many snyapse with motor neurons to carry signals away from spinal cord and brain
Axons are insulated with a myelin sheath composed of Schwann cells; controls ion movement |
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Peripheral Nervous System
Autonomic nerves |
Visceral functions
Carry signals to and from internal organs and glands Most organs are continually receiving both sympathetic and parasympathetic stimulation Sympathetic nerves signal heart to speed up, and parasympathetic stimulate it to slow down Which dominates depends on situation |
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Peripheral Nervous System
Somatic nerves |
Motor functions
Carry signals to and from skeletal muscle, tendons, and skin |
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Autonomic Nerves
Sympathetic nerves |
Originate in the thoracic and lumbar regions of the spinal cord; Ganglia are near the spinal cord
Promote responses that prepare the body for stress or physical activity (fight-or-flight response) |
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Autonomic Nerves
Parasympathetic nerves |
Originate in the brain and the sacral region of the spinal cord; Ganglia are in walls of organs
Promote housekeeping responses, such as digestion |
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Three Brain Divisions
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Hindbrain
Midbrain Forebrain |
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Hindbrain
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Reflex control of vital tasks and complex reflexes, unconscious motor activity
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Midbrain
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coordinates reflex responses to sight and sounds
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Forebrain
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Cerebrum: coordinating sensory and motor functions, memory, abstract thought (olfactory bulbs deal with smell)
Thalamus: sensory signal coordination Hypothalamus: controls homeostasis Limbic system (body responses to emotion); Pituitary gland (growth, metabolism); Pineal gland (circadian rhythms) |
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Cerebrospinal Fluid
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Surrounds the spinal cord and fills ventricles within the brain
Blood-brain barrier controls which solutes enter the cerebrospinal fluid Important implications also for medical treatment of diseases and disorders |
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Anatomy of the Cerebrum
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Largest and most complex part of human brain
Outer layer (cerebral cortex) is highly folded; a longitudinal fissure divides cerebrum into left and right hemispheres Inside the hemispheres is the limbic system which controls emotions and plays a role in memory |
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Drugs and Addiction
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A drug is a substance introduced into the body to provoke a specific physiological response
In addiction, a drug assumes an “essential” biochemical role in the body Stimulants increase alertness and body activity, then cause depression Caffeine, Nicotine, Cocaine, Amphetamines Depressants and hypnotics lower activity of nerves and parts of the brain Barbiturates, Alcohol, Morphine, Marijuana |
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Hormones
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Secreted by endocrine glands, endocrine cells, and certain neurons
Travel through the bloodstream to nonadjacent target cells Two main hormone types Steroid hormones Protein/Peptide hormones |
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Steroid Hormones
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Derived from cholesterol
Estrogens, progestins, androgens (such as testosterone), cortisol, aldosterone Most diffuse across the plasma membrane and bind to a receptor Hormone-receptor complex acts in nucleus to inhibit or enhance transcription |
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Protein Hormones
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Peptides, proteins, or glycoproteins
Glucagon, ADH, oxytocin, TRH, insulin, somatotropin, prolactin, FSH, LH, TSH Hormone binds to a receptor at cell surface Binding triggers a change in activity of enzymes inside the cell |
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Feedback Mechanisms
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Negative feedback
An increase in concentration of a hormone triggers activities that inhibit further secretion Positive feedback An increase in concentration of a hormone triggers activities that stimulate further secretion |
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Glucose Metabolism
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Hormones of the pancreas regulate the metabolism of glucose
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Glucose Metabolism
Glucagon |
(alpha cells) raises blood glucose levels
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Glucose Metabolism
Insulin |
(beta cells) lowers blood glucose levels
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Glucose Metabolism
Somatostatin |
(delta cells) inactivates alpha and beta cells
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Diabetes Mellitus
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Disease in which excess glucose accumulates in blood, then urine
Symptoms include Excessive urination Constant thirst Blurred vision Unexplained weight loss Unusual hunger Unusual fatigue Sores/wounds that do not heal |
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Two Types of Diabetes
Type 1 |
Autoimmune disease triggered by environment or possible viral infection (beta cells destroyed)
Usually appears in childhood Treated with insulin injections |
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Two Types of Diabetes
Type 2 |
Target cells don’t respond to insulin signals
Usually appears in adults Treated with diet, drugs, insulin |
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Risk Factors for Type 2 Diabetes
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Pre-Diabetes (impaired glucose tolerance)
Gestational diabetes Obesity (overweight problematic) People who are inactive Age Metabolic syndrome (high cholesterol, high triglycerides, low good ‘HDL’ and high bad ‘LDL’ and high blood pressure) Some minorities are at higher risk Possibly genetics |
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Gestational Diabetes
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Pregnancy induced glucose intolerance that can lead to diabetes during the 3rd trimester
Risk factors for mother: being overweight prior to pregnancy, over-eating during pregnancy, pre-diabetes, family history of diabetes, previous delivery of large baby, ethnicity Complications to fetus: birth defects, miscarriage, over-nutrition, excess growth, increased risk of developing diabetes later in life Can be tested for and treated |
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Complications of diabetes
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Heart disease and stroke (2-4X increased risk of death)
High blood pressure Blindness (leading cause of blindness in adults) Kidney disease (leading cause of end-stage renal disease) Nervous system damage Amputations Dental disease Complications of pregnancy Coma Lowered ability to fight off infections |
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Disease Management
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Losing weight coupled with proper nutritional and eating habits
Nutritional intake must be closely monitored Glucose levels must be monitored and adjusted Exercise Management of other diseases (cholesteral, high blood pressure, non-healing wounds) Treatment with various drugs including insulin |
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Islet-Cell Transplantation
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Beta cells from donor pancreas transferred into person with diabetes theoretically restoring proper insulin function
Benefits: reduces reliance on insulin injections, provides flexibility with nutritional intake, decreases chances of long-term complications from diabetes Risks: rejection, side effects from immunosuppressive drugs (including cancer) Success rate getting better, but only 400 patients world-wide have gotten the transplants with varying levels of disease regression Only 17 US hospitals do the procedure Type 1 diabetics currently only ones treated |
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Human Immunodeficiency Virus
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RNA retrovirus that upon infection of human cells permanently integrates into the cell’s genome
Enveloped virus with 2 major glycoproteins (gp120 and gp41) Carries many enzymes with it to effectively infect new host cells |
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Replication of HIV
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Initial infection occurs in cells of the immune system (macrophages and T cells), but over time HIV can gain access to other cell types as well, increasing disease symptomology
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Acquired Immunodeficiency Syndrome
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Combination of disorders that follows infection with HIV
In most individuals true symptoms of AIDS do not appear until 9-15 years after initial infection Major disorders include: Yeast (Candida) infections Pneumocystis pneumonia Karposi’s sarcoma (cancer) People generally die of infections or disorders, HIV itself does not directly kill |
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Transmission of HIV
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HIV does not live long outside human body and so it is most often spread by exchange of bodily fluids with an infected person
In the U.S., anal intercourse and needle sharing are main modes of transmission Becoming increasingly transmitted by vaginal intercourse and oral sex Can travel from mothers to offspring during pregnancy, birth, or breast-feeding Not known to be transmitted by food, air, water, casual contact, or insect bites |
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Effect of T-Cell Decline
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CD4 helper T cells play a vital role in immune function
They are required for both cell-mediated and antibody-mediated immunity Infected individual becomes vulnerable to other infections, which eventually result in death Treatment regimens are geared towards both reducing the number of free HIV in the blood and to bolstering the immune system to fight back |
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Treatment Regimens
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There is NO cure for HIV/AIDS
Once HIV genes are incorporated, no way to get them out; treatment will therefore be lifelong therapy There is NO vaccine against HIV HAART (Highly Active Anti-retroviral Therapy) AZT, other replication inhibitors + protease inhibitors slow the course of the disease and increase life span if given in combination Given as cocktails of a minimum of 3 anti-HIV drugs Problems of severe side effects and drug resistance Often given in context of other anti-microbial agents to prevent/treat opportunistic infections |
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LAK cells
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lymphocytes are extracted from tumors and exposed to lymphokines; once activated the cells can be re-injected into a patient to fight tumors
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