BSCI202 EXAM 1 REVIEW Anatomy Levels of Study Macroscopic Microscopic Necessary Life Functions o Large structures easily observable o Very small structures can only be viewed with microscope Maintain boundaries Movement locomotion and movement of substances Growth increases cell size and of cells Responsiveness ability to sense changes and react Digestion breakdown and absorption of nutrients Metabolism chemical reactions within the body Excretion eliminates waste from metabolic reactions Some Survival Needs Nutrients o Chemicals for energy and cell building o Includes carbs proteins lipids vitamins minerals Oxygen required for chemical rxns Water o 60 80 body weight o needed for many metabolic rxns homeostasis steady state stable body temp o o maintain blood plasma pH o maintain blood pressure o maintain water balance o stable blood sugar levels Levels of Organization cell smallest living unit tissues collection of cells of same type organs collection of 2 or more types of tissues put together into structures that perform a specific fx organ systems collection of organs that work together to accomplish a particular task Primary cells tissue classes muscle contraction generation of force connective connect anchor support epithelial barrier between body and external environment exchange nervous initiate transmit electrical impulses Body Fluid Compartments for a 70 kg man total body water 42 liters o 28 liters intracellular fluid o 14 liters extracellular fluid 3 liters plasma 11 liters interstitial fluid Immune and Lymphatic System returns fluids to blood vessels cleanses the blood protects the body from pathogens housekeeping maintenance Cardiovascular System transports materials in body via blood pumped by heart o oxygen o carbon dioxide 1 o nutrients o wastes Respiratory System keeps blood supplied with oxygen removes carbon dioxide maintains blood plasma pH Urinary System eliminates waste maintains acid base balance regulates water and electrolytes Reproductive System produces offspring not required for homeostasis Digestive System breaks down food allows for nutrient absorption into blood eliminates indigestible material Homeostasis is a Central Organizing Principle of Physiology the process of maintaining stable internal environment compatible for life most organ systems contribute to homeostasis exception reproductive negative feedback control homeostasis in action thermoregulation and neg feedback Homeostasis used for maintenance of a stable internal environment a dynamic state of equilibrium necessary for normal body functioning and to sustain life homeostatic imbalance a disturbance in homeostasis resulting in disease or death if not Maintaining Homeostasis Through Neural and Hormonal Control Systems corrected receptors sensors responds to changes in the environment stimuli send info to control center o o o detect level of regulated variable and provide input to integrating center control center integrating center o determines set point in brain desired level of regulated variable and analyzes info o compares set point to actual level of regulated variable and sends output to effectors to return regulated variable toward set point o determines appropriate response effector provides a means for response to the stimulus Negative Feedback Mechanisms negative feedback decreases the original stimulus or reduces its intensity works like a thermostat includes most homeostatic control mechanisms Negative Feedback Control in Homeostasis primary mechanism for maintaining homeostasis body s response to the original stimulus is to offset it so that it is within normal physiological set points external change triggers change in a regulated variable in internal environment this triggers a reaction to oppose the detected change and return regulated variable toward normal parameters set point 2 Understand Negative Feedback Mechanisms and how they work to cancel the error signal know all feedback loops discussed in lecture Negative feedback Includes most homeostatic control mechanisms Shuts off the original stimulus or reduces its intensity Works like a thermostat Two examples shown here 100mg dl Thermoneutral Zone normal body temp 37 degrees C thermoneutral zone if the range of outside temperature where alterations in bloodflow alone regulates body temp 25 30 C body temp increase blood flow to skin increases and chemical rxns occur at a frantic pace body proteins lose characteristic shape and stop functioning body temp decrease blood flow to skin decreases and metabolic rxns become slower and slower Control center Postive Feedback loop Input Information sent along afferent pathway to Receptor sensor positive feedback loops cause a rapid change in variable not a common mechanism for maintaining homeostasis response increases the original stimulus as opposed to canceling it out increases the original stimulus to push the variable further stimulus must end for response to end labor childbirth milk let down blood clotting Effector Output Information sent along efferent pathway to activate Change detected by receptor BLOOD Imbalance Blood Stimulus Produces change in variable Variable in homeostasis only fluid tissue in human body classified as a connective tissue components of blood Imbalance o living cells called formed elements Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis erythrocytes RBCs transports oxygen and carbon dioxide leukocytes WBCs defend against pathogens platelets cell fragments formed from megakaryocytes important in blood clotting o non living matrix plasma is the fluid and solutes Blood Hematocrit and beyond when blood is centrifuged Be able to explain what the Thermoneutral Zone is Know that Normal Body Temperature is 37oC o erythrocytes sink to bottom 45 of blood a percentage known as the hematocrit o buffy coat contains leukocytes and platelets less than 1 of blood the buddy coat is a thin whitish layer between erythrocytes and plasma Thermoneutral zone if the range of outside temperature where alterations in blood flow alone regulates body temperature 25 30oC o plasma rises to the top 55 of blood o average blood volume women 5 L men 5 5 L Body temperature increase blood flow to skin increases Body temperature decrease blood flow to skin decreases and PLASMA 55 Major functions Solvent for carrying other substances absorbs and Constituent Water 3 2 Salts electrolytes Na K Mg Ca chloride bicarbonate Plasma proteins
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