Organization and Homeostasis of Body Function PDF

organization and homeostasis of body func organization of physiological functions levels of organization atoms and molecules organellles cells tissues organs organ systems organism cells capable of carrying out basic functions f...

organization and homeostasis of body func organization of physiological functions levels of organization atoms and molecules organellles cells tissues organs organ systems organism cells capable of carrying out basic functions for survival metabolism of carbs, protein generation of energy each types of cells specifically perform one of few functions RBC - rich in hemoglobin and carry oxygen epithelial cells - secrete, abs substances muscle cells - generate movements in diff parts of body cells of similar function stick together to form tissues -> organs small intestines made of blood vessels smooth muscles epithelium connective tissues different organ systems interact to carry out body functions as organ systems human cardiovascular system heart -> cardiac muscles, epithelium, connective tissue heart contracts and relaxes rhythmically (cardiac cycle) to act as a pump it pumps deoxygenated blood from various organs to lungs for gas exchange and supply oxygenated blood to all organs heart adjust strength n freq of contraction according to body metabolic needs blood vessels made of smooth muscles, epithelium and connective tissues arteries - carry blood from heart to various organs in the body veins - carry blood from various organs back to heart major arteries that emerge from heart aorta - large artery responsible for channeling blood from heart to various organs  3 branches from aorta brachiocephalic trunk which bifurcates to right common carotid arter and right subclavian artery left common carotid artery left subclavian artery common carotid arteries supply head and neck region aorta travels inferiorly thru thoracic and abdominal cavities large arteries branch into smaller arteries smaller arteries branch into aterioles arterioles branch into capillaries capillaries converge into venules venules converge to smaller veins then to larger veins smooth muscles contract or relax to change diameters of small arteries/arterioles, changing amount of blood supplied to organ organ systems circulatory system/cardiovascular system - distributes materials by pumping blood thru organs  material exchange between body and surrounding environment respiratory system (oxygen and carbon dioxide) digestive system (nutrients and water) urinary system (water and waste) integumentary system - physically protects body and regulates body temperature musculoskeltal system - support and body movement, prod RBC in bone marrow nervous and endocrine system reg body fnc systems r all interdependent all living tissues/cells depend on cardio, resp and digestive system to supply oxygen and nutrients cardio system and urinary system remove metabolic wastes cardio system rely on nervous endocrine and urinary system to func Body fluid compartments water is 50-70% of total human body weight function as solvent for substances in body and medium for biochemical reactions quantifying total amount of solutes in aq sol  take into account dissociation of solutes e.g MgCl2 -> Mg2+ + 2Cl- (1 mol -> 3 osmoles) glucose does not dissociate in water (1 mole glucose => 1 osmole) 2 expressions of conc osmolality - osmoles per kilogram (mass), Osm/kg osmolarity - osmoles per liter Osm/L body fluid compartments intracellular fluid - fluid inside cells extracellular fluid - fluid outside cells interstitial fluid in extracellular space blood plasma within vessels transcellular fluids - synovial, cerebrospinal, intraocular, pleural fluids distribution of body fluid 70 kg male - 42 litres would be fluid ICF:ECF ratio -> 6:4 to 6.7:3.3 ICF is 2/3 of total body fluid -> 28L ECF 1/3 of total body fluid -> 14L 25% of ECF is plasma (3L) 75% is interstitial fluid (11L) ignores transcellular fluids as negligible solutes are distributed unevenly sodium and chloride more abundant in extracellular fluid than intracellular fluid potassium more abundant in intracellular proteins found in both ICF and blood plasma but not interstitial fluid small solutes (ions) can move in interstitial fluid n blood plasma, cannot move freely between intracellular and interstitial fluid  requires action of specific ion channels and transporters proteins are large n cant move between fluid comparments water moves freely between all bc of aquaporine on cell membranes when osmolarity of ext fluid changes, can cause water to shift between ICF and ECF swelling of brain -> intercranial pressure -> neurological symptoms (headache, nausea, lethargy)  important in intravenous infusions homeostasis internal environment all indiv cells surrounded by ECF in body ECG constitutes internal environment regulated variables maintained within predictable ranges conc of ions in ECF (K+, Ca2+, Na+, pH)  BGL blood O2 and CO2 level blood pressure blood volume body core temp fluctuation of regulated variables homeostasis is state of dynamic constancy some variables stay within narrow range some can change significantly throughouut day when variables become higher or lower than normal, body acts to restore them to set point ECF parameters Blood pressure pressure of blood against wall of arteries after contraction of heart (systole), blood enters arteries and causes blood pressure to increase after relaxation of heart (diastole), blood leaves arteries and causes blood pressure to decrease systolic pressure is highest blood pressure in cardiac cycle diastolic pressure is lowest homeostasis of blood pressure maintenance is important for cardio function and health systolic pressure 90-140 mmHg diastolic pressure 60-90 mmHg HYPERtension -> high blood pressure HYPOtension -> low blood pressure total blood vol, heart rate and diameter of arteries determine blood pressure resting heart rate - 60-100 bpm tachycardia - 100+ bpm bradycardia - less than 60 peripheral pulses arteris are elastic so expand and recoil when blood flows thru expansion and recoil of arterial wall felt as pulse when palpating peripheral arteries carotid brachial radial femoral popliteal posterior tibial dorsalis pedis pulse rate indicates heart rate for person w normal cardio health homeostatic control system to maintain homeostasis, body monitues regulated variables using sensors sensory cells (thermoreceptor, baroreceptor, chemoreceptor, osmoreceptors) cell components (cell surface receptors, enzymes) control center integrates signals from sensors and sends output signal to effectors control centres utilize electrical signals, chemical signals or both to control effector and bring changes in regulated variables effectors are organs/tissues that determine regulated variable effector examples blood pressure - heart, blood vessels, kidney blood glucose levels - liver, adipose tissue, skeletal muscle blood volume and osmolarity -kidneys and blood vessels neural mech sensory cells send signal to CNS via afferent pathway, then CNS signals efferent pathway signals along aff and eff pathway r in form of neurotrsnamitters and electrical signals (action potentials) endocrine mech endocrine glands can act as sensor and control centre changes in regulated variable stimulate endocrine glands to secrete hormones in circulation hormones circulate around body until cells/tissues reached neuroendocrine mech endocrine gland can act upon receiving signal from CNS via neurohormone or eff neural path blood pressure homeostasis increase in blood pressure stimulate baroreceptors in carotid sinus (bifurcation of common carotid arter) and arch of aorta medulla oblongata acts on heat and blood vessel to decrease blood pressure back to normal renal system targeted by neuroendocrine mech (adrenal glands) for long term blood pressure control blood glucose (fed state) properties of control mech negative feedback loop seen in most physio variables changes in regulated variables detected by sensor, effector acts to change regulated variable towards normal levels, eliminating stimulus reduces variability of regulated variable circadian rhythm affects physio variables body temp conc of growth hormone and cortisol in blood urinary excretion of ions follows 24h light-dark cycle  CNS receives input from eyes and in response, influence organ systems feedforward control (anticipatory response) negative feedback loops stabilise internal env, cant prevent changes from happening human body employs feedforward control to make adj before changes happen positive feedback non-homeostatic physiological func driven by positive feedback loops positive feedback amplify input signal bring about effect vv quickly, amplification of input signal accelerates process additional mech in place to turn off positive feedback loops e,g coagulation cascade, childbirth, surge of LH after follicular phase