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Define Physiology
Physiology is the science of body functions.
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What is the meaning of the word Physiology?
- Physis = nature
- Logos = science
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What tools do physiologists use to explain how the body works?
- - Biochemistry
- - Cell Biology
- - Genetics
- - Metabolics
- - Engineering
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What are the 2 "approaches" to Physiology, and what do they mean?
1. Reductionist Approach: study of the details by continuously dissecting into smaller and smaller pieces. (Problem: Scientist got lost, they needed to take a more "whole" approch)
2. Systems Approach: study of not only the function of the body but also the diseases. This approach aims to discover and fix the true problem and not just it's symptoms.
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What are the levels of organization in the body, from smallest to largest?
Chemical < Cells < Tissues < Organs < Organ Systems < Organisms
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What are the 3 principles of Physiology?
1. Simplicity: ex. brain cells - billions of them but can be classified in 4 groups
2. Interaction among different parts: ex. cell metabolims & blood circulation
3. Structure/Function relationship: cannot have one without the other
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Why are cells considered the smallest functional unit of life? (What processes do they carry out?)
- - Metabolically active (use oxygen/nutrients, produce carbon dioxide/wastes, synthesize complex molecules)
- - Sensitive to the environment
- - Growth
- - Reproduction (not all: ex. neurons)
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Name the 4 categories of cells in the body and their primary functions.
- - Neurons: initiate, transmit electrical impulses
- - Muscle cells: contraction, generation of force
- - Epithelial cells: barrier between internal/external environment, exchange (selectively permeable), form glands
- - Connective tissue cells: connect, anchor, support, ex. tendons, ligaments, blood, lymph, extracellular matrix
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Define Tissues
Collection of cells of same type and function.
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Define Organs
Collection of 2 or more types of tissues in a structure that perform a specific function.
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Define Organ Systems
Collection of organs that work together to accomplish a particular task.
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Define Internal Environment
Area of body within the epithelial membrane
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What areas inside the body are considered part of the external environment?
- - Lumen of respiratory system
- - GI system
- - Urinary system
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Name the body fluid compartments and the areas they occupy/do not occupy.
- - Total Body Water (TBW): occupy entire internal environment
- - Intracellular Fluid (ICF): inside cells (including blood cells)
- - Extracellular Fluid (ECF): occupy internal environment except inside cells
- - Plasma: fluid in bloodstream, occupy bloodstream except inside of blood cells
- - Interstitial Fluid (ISF): occupy internal environment except inside cells and bloodstream
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Define Homeostasis
Process of maintaining a stable internal environment compatible for life.
Capicity for self-regulation.
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What is the meaning of the word Homeostasis?
- Homeo = same
- Stasis = condition
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What needs to be maintained to achieve Homeostasis and what are the consequences of not maintaining them?
- The internal environment needs to be maintained:
- - ECF Composition
- - ECF Temperature
- - ECF Volume
Failure to maintain these resulsts in disease or death.
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Define Set Point
Desired level of regulated variable
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Define the role of a Sensor
Detect level of regulated variable and provide input to the integrating center
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Define the role of the Integrating Center
Compares set point to actual level of regulated variable
Controller; Hypothalamus
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Define Error Signal
Difference between actual level and set point
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Define role of Effectors
Receives output from integrating center to return regulated variable toward set point
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Describe the steps Negative Feedback
- 1. External change
- 2. Triggers change in regulated variable in internal environment
- 3. Triggers reaction to oppose the change and return regulated variable toward normal (set point)
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