Overview Necessary Life Functions 01 25 2011 Maintain homeostasis Movement Locomotion and movement of substances Growth Increase cell size and number of cells Responsiveness Ability to sense changes and react Digestion Break down and absorption of nutrients Metabolism Chemical reactions within the body Eliminates waste from metabolic reactions Some Survival Needs o Chemicals for energy and cell building o Includes carbohydrates proteins lipids vitamins and minerals Oxygen Required for chemical reactions o 60 80 of body weight o Needed for many metabolic reactions Homeostasis Steady state o Stable body temperature o Maintain blood plasma pH o Maintain blood pressure o Maintain water balance o Stable blood sugar levels Levels of Organization smallest living unit Tissues collection of cells of same type Organs collection of two or more types of tissues put together into structures that perform a specific function 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 70kg man total body water 42 liters 28 liters intracellular fluid ICF 14 liters extracellular fluid ECF o 3 liters o 11 liters interstitial fluid ISF Immune and Lymphatic System Returns fluids to blood vessels Cleanses the blood Transports materials in body via blood pumped by heart Protects the body from pathogens Housekeeping Cardiovascular System o Oxygen o Carbon dioxide o Nutrients o Wastes Respiratory System Keeps blood supplied with oxygen Removes carbon dioxide Maintains blood plasma pH Urinary System Eliminates wastes 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 o Most organ systems contribute to homeostasis o Exception Reproductive system o Negative Feedback Control in Homeostasis Body s response to cancel out a stimulus o Homeostasis in action Thermoregulation and Negative Feedback Homeostasis Maintenance of a stable internal environment A dynamic state of Homeostasis is necessary for normal body functioning and to equilibrium steady state sustain life Homeostatic Imbalance A disturbance in homeostasis resulting in disease or death if not corrected Maintaining Homeostasis Through Neural and Hormonal Control Systems Receptors sensors o Responds to changes in the environment stimuli o Sends information to control center o Detect level of regulated variable and provide input to integrating center Control center Integrating center o Determines set point usually in the brain desired level of regulated variable and analyzes information o Usually in the brain 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 Shuts off the original stimulus or reduces its intensity Works like a thermostat Included most homeostatic control mechanisms Negative Feedback Control in Homeostasis Primary mechanism for maintaining homeostasis Body s response the original stimulus is to offset it so that it is within normal physiology 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 Thermoneutral Zone Normal Body Temperature is 37C Thermoneutral zone is the range of outside temperature where alterations in blood flow alone regulates body temperature 25 30C Body temperature increase blood flow to skin increases Body temperature decrease blood flow to skin decreases Positive Feedback Loop Positive feedback loops cause a rapid change in a variable Not a common mechanism for maintaining homeostasis Response increases the original stimulus as opposed to cancelling it out Increases the original stimulus to push the variable farther Stimulus must end for response to end Labor child birth milk let down blood clotting If stimulus does not stop that is when pathology can occur Blood Blood 01 25 2011 The only fluid tissue in the human body Classified as a connective tissue Components of blood o Living cells called formed elements Blood Hematocrit and Beyond When blood is centrifuged Erythrocytes red blood cells transports oxygen and Leukocytes white blood cells defend body against carbon dioxide pathogens Platelets cell fragments formed from megakaryocytes important in blood clotting o Non living matrix Plasma is the fluid and solutes o Erythrocytes sink to the bottom 45 of blood a percentage known as the hematocrit o Buffy coat contains leukocytes and platelets less than 1 of blood the buffy coat is a thin whitish layer between the erythrocytes and plasma o Plasma rises to the top 55 of blood o Average blood volume Women 5 0L Men 5 5L Salts electrolytes for Plasma 55 Sodium Potassium Calcium Magnesium Chloride Bicarbonate Plasma proteins Albumin Fibrinogen Globulins Kwashiorkor extreme starvation Edema tissue swelling lack of osmotic balance Protein with gen is made inactive have it for when needed Blood plasma pH is 7 4 neutral Pure water has an osmolarity of 0 increase the number of solutes increase the osmolarity Physical Characteristics of Blood Blood is used as a vehicle of transport Color range o Oxygen rich blood is scarlet red o Oxygen poor blood is dull red pH between 7 35 7 45 Blood temperature is slightly higher than body temperature at 38C 100 4F Blood makes p 8 of body weight Osmolarity 275 295 300 mOsm L Blood Plasma is 90 Water 6 8 proteins which Increase osmotic pressure buffer H increase blood viscosity provide fuel during starvation Three Major classes of plasma proteins synthesized in liver except some globulins synthesized by lymphocytes o Albumins major contributor to plasma oncotic osmotic pressure and act as carriers o Globulins carriers clotting factors precursor proteins angiotensinogen immunoglobulins o Fibrinogen blood clotting Nutrients glucose amino acids
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