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Review for Exam 3 Friday 7th December 2007 Regulation of gene expression Pancreas cell Eye lens cell (in embryo) Nerve cell Glycolysis enzyme genes Crystallin gene Insulin gene Hemoglobin gene Key: Active gene Inactive gene Figure 11.3 How do we develop? • On ovulation day, egg and sperm fuse to form zygote. • Zygote divides, implants onto uterus and grows into Embryo and hangs out for about 9 months. • Embryo decides it is time to breathe air, fetal adrenal glands trigger contractions and out comes baby. • Baby grows grows grows into child, child undergoes puberty and becomes adult. • Adult lives, works, reproduces (perhaps), gets gray hair and croaks. REMEMBER!!!!!!!!! • If viable sperm contact an egg at the time of ovulation fertilization will occur. • This “typically” occurs on day 14. Remember Day 1 is first day of menstruation. • The fertilized egg will implant on day 6. • The new embryo will begin to produce HCG-Human Chorionic Gonadotripin. • HCG maintains the corpus luteum and allows the production of progesterone and estrogen until the placenta takes over this task. • Remember Fertilization Egg must develop and be released on ovulation day. • Egg must be correctly positioned in the oviduct and attract sperm. • Vaginal tract must activate sperm. • Hormonal levels must be exact. • Ensure only one sperm joins with egg. Remember - Fertilization • Sperm must undergo capacitation--process of activation by substances in female vaginal tract fluids. • Sperm motor from vagina up through cervix, uterus, to the oviduct. • Many sperm attempt fertilization, only one succeeds (except for twins). Development before Implantation • Fertilization • Cleavage: successive rounds of cell division. A one cell zygote--2 cell--4 cell--8 cell-. • Cleavage occurs in the oviduct. • Morula: 16 cell stage--enters the uterus. • Key cell differentiation step: – Trophoblast – Inner Cell Mass Development before Implantation • Blastocyst • Hollow ball of cells. • Each cell is called a blastomere. • Inner cell mass--become the embryo. • Trophoblast--Incredible Altruistic Cells! – Escape from the Zona Pellucida – Digest through Endometrium – Initiate HCG secretion – Form the Placenta Gastrulation • Truly the most important day of your life! • Process of forming 3 germ layers-this process requires cell movement. • Each germ layer forms specific tissues and organs – Ectoderm--(blue)--will form skin and nervous system. – Mesoderm--(red)--will form muscles, kidneys, connective tissue, and reproductive organs. – Endoderm--(yellow)--will form digestive tract, lungs, liver and bladder. Figure 12.8b Drugs and addiction • Drug addiction is a condition characterized by compulsive drug intake, craving and seeking, despite negative consequences associated with drug use. • The activity of any drug varies with dose – The amount of the drug taken over time • The amount of a drug taken to be toxic or lethal depends upon the chemical structure of the drug – Also body size and other physiological variables The Respiratory System • During inspiration or inhalation, air is conducted toward the lungs. • During expiration or exhalation, air is conducted away from the lungs. • Works in conjunction with the cardiovascular system for RESPIRATION to occur • Breathing –air in and out of lungs • External respiration –exchange of gasses between air & blood • Internal respiration – exchange between blood &tissue fluid • Cellular respiration –production of ATP in cells The Respiratory System • Two parts: • Upper Respiratory Tract • Nasal Cavities – Filter, warm and moisten air • Pharynx – Connection to surrounding regions • Glottis – Passage of air into larynx • Larynx – Sound production The Respiratory System • Lower Respiratory Tract • Trachea – Passage of air to Bronchi • Bronchi – Passage of air to lungs • Bronchioles – Passage of air to each alveolus • Lungs – Gas Exchange The Trachea • Windpipe – connects larynx to primary bronchi. • Held open by cartilage • Goblet cell – Makes mucus • Mucosa contains layer of pseudostratified ciliated epithelium – Sweep dirt and excess mucus upwards The Bronchial Tree • The trachea divides into L & R primary bronchi – eventually branch into secondary bronchi and then into bronchioles. – Each bronchiole leads to an elongated space enclosed by alveoli. The Lungs • These lie on either side of the heart within the thoracic cavity. • Total cross-sectional area of 50 – 70 meter squared (1 ½ Tennis courts) – Right lung has three lobes and the left lung has two lobes. • This allows room for the heart – Each lobe is divided into lobules, further divided into bronchioles serving many alveoli. Alveoli • There are 300 m alveoli per set of lungs. – Each one is made up of squamous epithelium and blood capillaries. • Gas exchange occurs: O2 diffuses across the alveolar wall and enters blood – CO2 goes in other direction • Lined with lipoprotein – lowers surface tension and prevents them from closing. Mechanism of Breathing • Respiratory Volumes – Tidal volume is the amount of air that moves in and out with each breath. – Vital capacity is the maximum amount of air that can be moved out in a single breath. • Inspiration can be increased by expanding the chest (inspiratory reserve volume). – Residual volume is the air remaining in the lungs after deep exhalation Gas Exchanges in the Body • External respiration refers to gas exchange between air in the alveoli and blood in the pulmonary capillaries. – Blood entering the pulmonary capillaries has a HIGHER partial pressure of CO2 than atmospheric air. • CO2 diffuses out of the blood into the lungs. • Carried in blood plasma as bicarbonate ions (HC03 ions) – Blood entering the pulmonary capillaries has a LOWER partial pressure of O2 than the avlvoli. • O2 diffuses into plasma and then red blood cells • Binds with hemoglobin – forms oxyhemoglobin Internal Respiration • Internal respiration - gas exchange between the blood in systemic capillaries and the tissue fluid. – O2 diffuses out of the blood into the tissue because the partial pressure of O2 in tissue fluid is LOWER than that of blood. • O2 leaves hemoglobin and enters tissue fluid – CO2 diffuses into the blood from the tissue because the partial pressure of CO2 in tissue fluid is HIGHER than that of blood • Internal Respiration occurs at systemic capillaries – that is in the major organs. • External Respiration occurs at pulmonary capillaries – that is in the lungs ONLY Addiction • Ventral tegmental area (VTA) – Thought to be positive enforcement area (pleasure center). – Experiments on rats and rhesus monkeys have show that both would rather electrically stimulate this area of the brain than eat – even if near to starvation • Nucleus accumbens (NA) – joined to the VTA by synaptic connections – Interprets the stimulation signal from the VTA Addiction • Frontal cortex (FC) – Play a part in impulse control, judgment, language production, working memory, motor function, problem solving, sexual behavior, socialization and spontaneity. – Assist in planning, coordinating, controlling and executing behavior. – This is why behavioral changes occur which are hard to break Addiction • Opiates, marijuana, caffeine, and alcohol all produce VTA self-reinforcing effects. • Drugs of abuse take over the neuronal circuitry involved in motivation and reward, leading to altered engagement of learning processes. • Because of this, drug-associated cues can trigger cravings as well as unconcious or compulsive drug-seeking behavior, with the sense that voluntary control over drug use is lost Addiction • Objects, people or places also seem to to be strongly associated with the drug experience, making them 'Triggers' to 'Cravings' – increase the chances of further use. • Animal studies have shown drug availabilty over and above the actual effects of the substance) are associated with stimuli, exposure to objects associated with use trigger the release of adrenaline (Fight or flight) – this excitation can be perceived as a 'need' to use Addiction • Users in addictive drugs in the US in 1991 • The top three are widely not considered drugs by most of the population • All of these three produce addictive behavior. Primary Lymphatic Organs • Lymphatic organs contain large numbers of lymphocytes (White Blood cells). • Primary organs are:– Red Bone Marrow. • Site of stem cells. – Source of B lymphocytes. – Thymus Gland. Lymphocytes from bone marrow pass through to form T-lymphocytes • Produces thymic hormones (thymosin). • Aids in T lymphocyte maturation. Secondary Lymphatic Organs • Secondary lymphatic organs are places where lymphocytes encounter and bind with antigens. – Spleen. – Lymph nodes. – Tonsils. – Peyer’s patches. Secondary Lymphatic Organs • Spleen – upper left of abdominal cavity behind stomach. Sectioned off by connective tissue- white pulp & red pulp. – White pulp – lymphocytes – Red pulp – filters blood. Blood entering the spleen passes through red pulp before it leaves (network of sinuses) – FRAGILE Secondary Lymphatic Organs • Lymph Nodes – occur along lymphatic vessels. Formed from connective tissue. – Packed full of Blymphocytes – As lymph courses through sinuses it is filtered by macrophages, which engulf pathogens and debris. – Also present- Tlymphocytes – fight infection and attack Secondary Lymphatic Organs • Tonsils – patches of lymphatic tissue. • Perform the same function as lymph nodes – First line of defense • Peyer’s Patches – on the intestinal wall and appendix. Attack pathogens that ender the body by way of the intestinal tract. Innate Immunity • One important function of the immune system is to promote growth and repair after injury – Either via physical damage or microorganisms • The mobilization of innate immune cells to get rid of damaged cells or microorganisms is called inflammation • Small molecules called cytokines are also involved T Cells • Provide cell-mediated immunity. • Produced in bone marrow, mature in thymus. • Antigen must be presented in groove of HLA molecule. • Cytotoxic T cells destroy non-self proteinbearing cells. • Helper T cells secrete cytokines that control the immune response. B Cells • Provide antibody-mediated immunity against bacteria. • Produced and mature in bone marrow. • Reside in spleen and lymph nodes. – Circulate in blood and lymph. • Directly recognize antigen and then undergo clonal selection. • Clonal expansion produces antibody-secreting plasma cells and memory B cells. Clonal selection Theory • The antigen selects which lymphocyte will undergo clonal expansion and produce more lymphocytes with the same type of antigen receptor. – Some become memory cells – long term immunity to the same infection. – B-cells become plasma cells – fight infection – Apoptosis – when danger of infection is over, all plasma cells Antibodies • Classes. – IgG - Enhances phagocytosis. – IgM - Activates complement proteins. – IgA - Prevents attachment of pathogens. – IgD - Antigen receptors on virgin B cells. – IgE - Immediate allergic response.