physiology summaries

physiology summaries - Chapter 1 Summary The scope of human...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 1 Summary The scope of human physiology - physiology is the study of how living organisms work - physiologists are interested in the regulation of body function - diseases states are physiology “gone wrong” (pathophysiology) How is the body organized? - cells are the simplest structural units into which a complex multicellular organism can be divided and still retain the functions characteristic of life - cell differentiation results in the formation of four general categories of specialized cells - muscle cells generate the mechanical activities that produces force and movement - neurons initiate and conduct electrical signals - epithelial cells form barriers and selectively secrete and absorb ions and organic molecules - connective-tissue cells connect, anchor, and support the structures of the body - specialized cells associate with similar cells to form tissues: muscle tissue, nervous tissue, epithelial tissue, and connective tissue - organs are composed of two or more of the four kinds of tissues arranged in various proportions and patterns. Many organs contain multiple, small, similar functional units - an organ system is a collection or organs that together perform an overall function body fluid compartments - the body fluids are enclosed in compartments - the extracellular fluid is composed of the interstitial fluid (the fluid between cells) and the blood plasma - of the extracellular fluid, 75-80% is interstitial fluid, and 20-25% is plasma - interstitial fluid and plasma have essentially the same composition except that plasma contains a much higher concentration of protein - extracellular fluid differs markedly in composition from the fluid inside cells – the intracellular fluid - approximately 1/3 of body water is in the extracellular compartment, and 2/3 is intracellular - the differing compositions of the compartments reflect the activities of the barriers separating them homeostasis: a defining feature of physiology - the body’s internal environment is the extracelluar fluid - the function of organ systems is to maintain a stable internal environment – this is called homeostasis - numerous variables within the body must be maintained homeostatically - when homeostasis is lost for one variable, it may trigger a series of changes in other variables general characteristics of homeostatic control systems - homeostasis denotes the stable condition of the internal environment that results from the operation of compensatory homeostatic control systems - in a negative feedback control system, a change in the variable being regulated brings about responses that tend to push the variable in the direction opposite to the original change. Negative feedback minimizes changes from the set point of the system, leading to stability - homeostatic control systems minimize changes in the internal environment but cannot maintain complete constancy - feedforward regulation anticipates changes in a regulated variable, improves the speed of the body’s homeostatic responses, and minimizes fluctuations in the level of the variable
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/29/2012 for the course PHYSIOL 335 taught by Professor Staff during the Spring '08 term at Wisconsin.

Page1 / 5

physiology summaries - Chapter 1 Summary The scope of human...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online