Anatomy and Physiology IBio 130 Professor Peter Smith D.P.T, ATC http://www2.sunysuffolk.edu/smithpr/
Overview of Anatomy and Physiology • Anatomy – the study of the structure of body parts and their relationships to one another • Physiology – the study of the function of the body’s structural machinery • Cytology – study of the cell • Histology – study of tissues
Levels of Structural Organization Smooth muscle cell Molecules Cellular levelCells are made up of molecules 2 Atoms Chemical levelAtoms combine to form molecules 1 Smooth muscle tissue Heart Tissue levelTissues consist of similar types of cells 3 Cardiovascular system Blood vessels Epithelial tissue Smooth muscle tissue Blood vessel (organ) Organismal levelThe human organism is made up of many organ systems 6 Connective tissue Organ levelOrgans are made up of different types of tissues 4 Organ system levelOrgan systems consist of different organs that work together closely 5
Organ Systems Interrelationships • Nutrients necessary for energy production for all the cells in the body are absorbed in the digestive system. • O2 and CO2 are exchanged by the respiratory system and distributed throughout the blood by the circulatory system. • Metabolic wastes are eliminated by the urinary and respiratory systems
Homeostasis • Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world • The internal environment of the body is in a dynamic state of equilibrium • There is a tight regulation of hormones (chemical messages), changes is body temperature and the nervous system. • The body is designed to maintain homeostasis! • Diets fail because calorie restriction can promote a rapid drop in body weight. Your physiology sees this as a threat to your survival. To restore homeostasis metabolism is reduced.
Homeostatic Control Mechanisms Controlcenter Input:Informationsent alongafferentpathway to 3 Output:Information sentalong efferentpathway to 4 Effector Receptor (sensor) Changedetectedby receptor 2 Response ofeffector feedsback to influencemagnitude of stimulus andreturnsvariable tohomeostasis 5 Stimulus:Produceschangein variable 1 Imbalance Variable (in homeostasis) Imbalance
Negative Feedback • In negative feedback systems, the output shuts off the original stimulus.
Negative Feedback • When the body temperature is higher than the set point the blood vessels dilate bring the blood closer to the skin. Evaporated sweat cools the body • When the body is cold blood is shunted toward the internal organs way from the skin to minimize heat lose. Shivering creates heat as a byproduct of muscle metabolism
Positive Feedback • In positive feedback systems, the output enhances or exaggerates the original stimulus • Example: Regulation of blood clotting Figure 1.6
Homeostatic Overview • Under normal circumstances the body’s homeostatic controls are maintained by negative feedback loops. • Diseases are often made worse because of failure of the normal negative feedback mechanisms. The creation of positive feedback loops that further drive the body away from its homeostatic mechanisms. Example: • Diseased lungs reduce the body’s ability to bring in oxygen to the cells. The body tries to adapt by make more oxygen carrying red blood cells. The result is thicker blood. This makes the heart work harder and even get larger. The larger heart put pressure on the lungs.