BIOL 2457 1st Edition Lecture 2Outline of Last LectureI. Form and FunctionOutline of Current LectureII. Metabolism and Responsiveness Metabolisma. Sum of all the chemical process that occur in the bodyi. Catabolism1. The breakdown of complex chemical substances into simpler componentsii. Anabolism1. The building up of complex chemical substances from smaller, simpler componentsIII. Responsivenessa. Body’s ability to detect and respond to changesi. Decrease in body temperatureii. Responding to soundiii. Nerve (electrical signals) and muscle cells (contracting)IV. Movement and GrowthV. Movementa. Motion of the whole body i. Includes organs, cells, and tiny subcellular structuresii. Example: Leg muscles move the body from one place to anotherVI. Growtha. Increase in body sizei. Due to an increase in existing cells, number of cells, or bothii. Example: In bone growth materials between cells increaseVII. Differentiation and ReproductionVIII. Differentiationa. Development of a cell from an unspecialized to specialized statei. Cells have specialized structures and functions that differ from precursorcellsii. Stem cells give rise to cells that undergo differentiationIX. Reproductiona. Formation of new cells (growth, repair, or replacement)b. Production of a new individualX. Clinical Connection: AutopsyXI. Postmortem (after death) examination of the body and internal organsXII. Uses:a. Determine the cause of deathb. Identify diseases not detected during lifec. Determine the extent of injuries and contribution to deathd. Identify hereditary conditionsXIII. HomeostasisXIV. A condition of equilibrium (balance) in the body’s internal environmenta. Dynamic conditionb. Narrow range is compatible with maintaining lifec. Examplei. Blood glucose levels range between 70 and 110 mg of glucose/dL of bloodii. Whole body contributes to maintain the internal environment within normal limitsXV. Homeostasis and Body FluidsXVI. Maintaining the volume and composition of body fluids is importanta. Body fluids are defined as dilute, watery solutions containing dissolved chemicals inside or outside of the cellb. Intracellular Fluid (ICF)i. Fluid within cellsc. Extracellular Fluid (ECF)i. Fluid outside cellsii. Interstitial fluid is ECF between cells and tissues XVII. ECF and Body LocationXVIII. Blood Plasmaa. ECF within blood vesselsXIX. Lympha. ECF within lymphatic vesselsXX. Cerebrospinal fluid (CSF)a. ECF in the brain and spinal cordXXI. Synovial fluida. ECF in jointsXXII. Aqueous humor and vitreous bodya. ECF in eyesXXIII. Interstitial Fluid and Body FunctionXXIV. Cellular function depends on the regulation of the composition of interstitial fluidXXV. Interstitial fluid is the body’s internal environmentXXVI. Composition of interstitial fluid changes as substances move between plasma and the interstitial fluida. Movement back and forth across capillary walls provides nutrients (glucose, oxygen, ions) to tissue cells and removes waste (carbon dioxide)XXVII. Control of HomeostasisXXVIII. Homeostasis is constantly being disrupteda. Physical insultsi. Intense heat or lack of oxygenb. Changes in the internal environmenti. Drop in blood glucose due to lack of foodc. Physiological stressi. Demands of work or schoold. Disruptionsi. Mild and temporary (balance is quickly restored)ii. Intense and prolonged (poisoning or severe infections)XXIX. Feedback SystemsXXX. Cycle of eventsi. Body is monitored and re-monitoredii. Each monitored variable is termed a controlled conditionXXXI. Three basic componentsi. Receptorii. Control centeriii. EffectorXXXII. Feedback SystemsXXXIII. Receptora. Body structure that monitors changes in a controlled conditionb. Sends input to the control centeri. Nerve endings of the skin in response to temperature changeXXXIV. Feedback SystemsXXXV. Control Centera. Brainb. Sets the range of values to be maintainedc. Evaluates input received from receptors and generates output commandd. Output involves nerve impulses, hormones, or other chemical agentse. Example:i. Brain acts as a control center receiving nerve impulses from skin temperature receptorsf. Feedback SystemsXXXVI. Effectora. Receives output from the control centerb. Produces a response or effect that changes the controlled conditioni. Nearly every organ or tissue can serve as an effectorc. Example:i. Body temperature dropsii. The brain sends an impulse to the skeletal muscles to contract iii. Shivering occurs to generate heatd. Negative and Positive Feedback SystemsXXXVII. Negative Feedback systemsa. Reverses a change in a controlled conditioni. Regulation of blood pressure (force exerted by blood as it presses again the walls of the blood vessels)XXXVIII. Positive Feedback systemsa. Strengthen or reinforce a change in one of the body’s controlled conditionsi. Normal child birthXXXIX. Negative Feedback: Regulation of Blood PressureXL. External or internal stimulus increase BPa. Baroreceptors (pressure sensitive receptors)i. Detect higher BPii. Send nerve impulses to brain for interpretationiii. Response sent via nerve impulse sent to heart and blood vesselsiv. BP drops and homeostasis is restoredv. Drop in BP negates the original stimulusXLI. Uterine contractions cause vagina to openXLII. Stretch-sensitive receptors in cervix send impulses to brainXLIII. Oxytocin is released into the blood XLIV. Contractions enhanced and baby pushes farther down the uterusXLV. Cycle continues to the birth of the baby (no stretching)XLVI. Positive Feedback: Blood LossXLVII. Normal condition, heart pumps blood under pressure to body cells (oxygen and nutrients) XLVIII. Severe blood lossa. Blood pressure dropsb. Cells receive less oxygen and function less efficientlyc. If blood loss continuesi. Heart cells become weakerii. Heart doesn’t pumpiii. BP continues to fallXLIX. Homeostatic ImbalancesL. Normal equilibrium of body processes is disrupteda. Moderate imbalancei. Disorder or abnormality of structure and functionii. Disease specific for an illness with recognizable signs and symptomsiii. Signs are objective changes such as a fever or swellingiv. Symptoms are subjective changes such as headacheb. Severe imbalancei. DeathLI. Homeostatic Imbalances: Areas of ScienceLII. Epidemiologya. Occurrence of diseasesb. Transmission in a communityLIII. Pharmacologya. Effects and uses of drugsb. Treatment of diseaseLIV. Clinical Connection: Diagnosis of DiseaseLV. Distinguishing one disorder or disease from anothera. Signs