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Published byErin Johnson Modified over 9 years ago
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Ch. 1 – Characteristics of Life & Organization of the Human Body
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What is the difference between Anatomy and Physiology?
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A. Anatomy- study of the structures of an organism
-Examples of 4 subcategories:
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1. Gross anatomy- large, what you can see
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2. Microscopic anatomy - tiny
Cytology= study of cells Histology= tissues
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3. Developmental Anatomy
-structure of an embryo (embryology)
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4. Pathological anatomy- diseased structures
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B. Physiology- study of the functions of an organism
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What are the levels of organization in the human body?
-chemical (subatomic, atomic, molecules, macromolecules) -organelles -cells (differentiated to perform unique functions) 100 Trillion! -tissues -organs -organ system (see below) -organism (human)
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Virtually all processes in the body occur in order to maintain Homeostasis
What is Homeostasis?
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Homeostasis- an organism’s maintenance of a relatively constant internal state within set ranges.
Examples: Temp.= ~ °F b.p.= ~ 120/80 mmHg glucose= ~ mg/dl Blood pH= 7.4 hydration= ~60% H2O MANY, MANY more!
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Homeostatic control mechanisms-
-known as a feedback control loop -virtually all of the body’s organ systems can be involved -there are three basic components: -Sensor – senses a change (a “stimulus”) -Integrator, (control center) – interpret the change -Effector – responds to the change
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EFFECTOR: the heart begins to beat faster thereby increasing pressure.
Example: SENSOR: pressure sensor in the walls of the heart and major arteries senses low blood pressure and sends a signal to the brain. INTEGRATOR: Medulla oblongata in the brain determines degree in which b.p. must be corrected and send a signal back to the heart. EFFECTOR: the heart begins to beat faster thereby increasing pressure.
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NEGATIVE feedback mechanism-
-creates a response that opposes the initial disturbance. (reverses the change) -work to stabilize physiological variables -are responsible for maintaining homeostasis
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POSITIVE feedback mechanism-
-amplifies or reinforces the change that is occurring CANCER! -can be harmful or disasterous -very few normal positive feedback mechanisms -childbirth, bloodclotting, a sneeze
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