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Questions and Answers
What best defines homeostasis?
What best defines homeostasis?
- The ability to adapt to external environmental pressures.
- A state of complete equilibrium within the body.
- The maintenance of a relatively stable internal environment. (correct)
- Fresh intake of nutrients to keep the body functioning.
Which of the following correctly describes negative feedback?
Which of the following correctly describes negative feedback?
- Initiates a process to amplify change.
- Acts only during times of stress.
- Maintains an ongoing action or response.
- Reverses a change to return to a set point. (correct)
Which sequence represents the correct levels of biological organization?
Which sequence represents the correct levels of biological organization?
- Organs → Organ Systems → Organism → Tissues → Cells
- Molecules → Atoms → Organs → Organ Systems → Organism
- Atoms → Cells → Tissues → Organs → Organ Systems → Organism (correct)
- Cells → Tissues → Molecules → Atoms → Organs
How does protein-mediated transport differ from simple diffusion?
How does protein-mediated transport differ from simple diffusion?
Which of the following best describes vesicular transport?
Which of the following best describes vesicular transport?
Which characteristic distinguishes movement through ion channels from facilitated diffusion?
Which characteristic distinguishes movement through ion channels from facilitated diffusion?
What is true regarding active transport?
What is true regarding active transport?
What depicts a main reason for homeostasis failure?
What depicts a main reason for homeostasis failure?
Which molecule passes through biological membranes via simple diffusion?
Which molecule passes through biological membranes via simple diffusion?
Which of the following describes facilitated diffusion?
Which of the following describes facilitated diffusion?
Flashcards
Physiology
Physiology
The study of how living organisms and their parts function normally.
Levels of Organization
Levels of Organization
The order from smallest to largest: Atoms → Molecules → Cells → Tissues → Organs → Organ Systems → Organism.
Homeostasis
Homeostasis
Maintaining a stable internal environment despite outside changes. Like a thermostat keeping your house at a set temperature.
What happens when homeostasis fails?
What happens when homeostasis fails?
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Negative Feedback
Negative Feedback
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Positive Feedback
Positive Feedback
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Feedforward Control
Feedforward Control
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Study Notes
Chapter 1: Physiology
- Physiology is the study of the normal functioning of living organisms and their parts.
- Levels of organization from smallest to largest: atoms → molecules → cells → tissues → organs → organ systems → organism.
Homeostasis
- Homeostasis is the maintenance of a relatively stable internal environment despite external changes.
- Homeostasis is a dynamic steady state, not equilibrium.
- Disease or sickness occurs when homeostasis is disrupted for long periods.
- Negative feedback: Reverses a change to return to a set point (e.g., regulating body temperature).
- Positive feedback: Amplifies a change, moving the system further from the set point (e.g., childbirth).
- Feedforward control: Anticipates changes and activates mechanisms in advance (e.g., salivation before eating).
Chapter 5: Osmotic and Electrical Equilibrium
- Osmotic Equilibrium: The total solute concentration is equal on both sides of the cell membrane.
- Chemical Disequilibrium: Different solutes have uneven distributions across the cell membrane (e.g., sodium higher outside, potassium higher inside).
- Electrical Disequilibrium: Ions create a charge difference across the membrane (resting membrane potential, typically around -70 mV). This is maintained by ion channels and pumps (e.g., Na+/K+ ATPase).
Membrane Transport
- Simple Diffusion: Passive movement of molecules down their concentration gradient (e.g., oxygen and carbon dioxide).
- Protein-Mediated Transport:
- Facilitated Diffusion: Passive transport using carrier proteins (e.g., glucose transporters).
- Active Transport: Requires energy (ATP) to move molecules against their concentration gradient (e.g., Na+/K+ pump).
- Direct active transport uses ATP directly.
- Indirect active transport uses the energy from an existing gradient.
- Ion Channels: Allow specific ions to pass through the membrane (e.g., voltage-gated Na+ channels) - passive due to electrochemical gradient.
- Vesicular Transport: Active transport involving vesicles (e.g., endocytosis, exocytosis, and phagocytosis).
Transport Across Membranes
- Channels:
- Passive movement of ions or water.
- Selective based on size and charge.
- Fast, allowing many ions to pass simultaneously.
- Facilitated Diffusion Carriers:
- Passive, binds specific molecules.
- Slower than channels, undergoes conformational changes for each molecule.
- Example: GLUT transporters.
- Active Transport Carriers:
- Require ATP or other energy sources.
- Moves molecules against their gradients.
- Example: Na+/K+ ATPase pump (3 Na+ out, 2 K+ in).
Specific aspects of transport:
- Specificity: Carriers are specific to certain molecules or closely related molecules (e.g., glucose transporters).
- Competition: Similar molecules can compete for the same carrier.
- Saturation: There is a maximum transport rate (Tmax) for carriers at high substrate concentrations.
- Ion Permeability and Membrane Potential: Changes in ion permeability alter membrane potential (e.g., increased Na+ permeability depolarizes the membrane).
Examples of Carrier-mediated Transport:
- Insulin secretion (beta cells), requiring the understanding of glucose levels impacting the permeability of various membrane proteins like K+ ATP and voltage gated calcium channels, to influence insulin secretion.
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