Podcast Beta
Questions and Answers
What is a key characteristic of active transport mechanisms?
In primary active transport, the energy derives directly from which source?
What process uses the electrochemical gradient established by primary active transport?
Which example is NOT associated with primary active transport?
Signup and view all the answers
What is the general function of carrier proteins in the context of active transport?
Signup and view all the answers
What is the primary fluid found within all body cells?
Signup and view all the answers
Which of the following fluids surrounds the cells and serves as an exchange medium?
Signup and view all the answers
How many liters of plasma are there in a body with 70 kg total body water?
Signup and view all the answers
What significant charge characterizes the proteins found in intracellular fluid?
Signup and view all the answers
What is the role of homeostasis in the body?
Signup and view all the answers
Which component of extracellular fluid is responsible for the transport of nutrients and waste products?
Signup and view all the answers
What is the main ion found in high concentration within intracellular fluid?
Signup and view all the answers
What distinguishes extracellular fluid from intracellular fluid?
Signup and view all the answers
Which process is primarily responsible for maintaining osmotic balance in the body?
Signup and view all the answers
What is the main factor contributing to the high fluid levels in the intracellular space compared to extracellular fluid?
Signup and view all the answers
Which type of transport mechanism requires a special membrane protein?
Signup and view all the answers
What is the primary characteristic that distinguishes active transport from passive transport mechanisms?
Signup and view all the answers
What is the approximate resting membrane potential of a cell?
Signup and view all the answers
Which transport mechanism moves substances in the same direction as sodium ions?
Signup and view all the answers
What is a common feature of facilitated diffusion?
Signup and view all the answers
What is NOT a property of passive transport mechanisms?
Signup and view all the answers
Which physiological process relies on changes in resting potential for signaling?
Signup and view all the answers
How does active transport typically move substances?
Signup and view all the answers
What defines amphipathic molecules?
Signup and view all the answers
What process is essential for maintaining osmotic balance in cells?
Signup and view all the answers
What is the primary direction of water movement during osmosis?
Signup and view all the answers
What occurs to a cell in a hypotonic solution?
Signup and view all the answers
What is the osmotic pressure of human cells equivalent to?
Signup and view all the answers
What happens to cells in a hypertonic solution?
Signup and view all the answers
Why is an isotonic NaCl solution preferred over an isoosmotic solution of penetrating solutes like urea for restoring blood volume?
Signup and view all the answers
In which scenario would osmosis not occur?
Signup and view all the answers
What is the effect of an isotonic environment on a cell?
Signup and view all the answers
What is the primary goal of homeostasis?
Signup and view all the answers
What role does osmosis play at the tissue level?
Signup and view all the answers
Which factor is NOT homeostatically regulated?
Signup and view all the answers
Which component of the homeostatic control mechanism is responsible for monitoring internal conditions?
Signup and view all the answers
What is the function of the effector in the homeostatic control mechanisms?
Signup and view all the answers
Homeostasis relies primarily on which type of feedback mechanism?
Signup and view all the answers
What happens when there is a failure to compensate for homeostatic imbalances?
Signup and view all the answers
Which of the following best describes the relationship between homeostasis and the external environment?
Signup and view all the answers
Which of the following is an example of a factor that homeostasis regulates?
Signup and view all the answers
In the context of homeostasis, what does the term 'set point' refer to?
Signup and view all the answers
What might be a physiological consequence of failing to regulate body temperature?
Signup and view all the answers
Study Notes
Osmosis
- Movement of water through a selectively permeable membrane from regions of higher concentration to regions of lower concentration.
- Water moves from high concentration of water to lower concentration of water (and from lower concentration of solutes to higher concentration of solutes).
- Important at cellular level, causing cells to shrink or swell.
- Important at tissue level, osmosis occurs through epithelial cells in the GIT and renal system. It also occurs through capillary walls.
Osmotic Pressure
- The osmotic pressure inside human cells is equal to the concentration of a 0.9% solution of sodium chloride (99.1 g water + 0.9 g NaCl).
- 0.9% NaCl solution is called “normal or physiologic saline”.
- Hypotonic: OP in extracellular fluid is less than OP intracellular fluid, causing water to enter the cell.
- Hypertonic: OP in extracellular fluid is greater than OP intracellular fluid, causing the cell to lose water.
- Isotonic: OP in extracellular fluid is equal to OP intracellular fluid, resulting in hydrostatic equilibrium.
Active Transport
- Carrier molecules transport substances across a membrane from regions of lower concentration to regions of higher concentration.
- Examples: glucose, amino acids, sodium ions, potassium, calcium, and Hydrogen ions.
- It is carrier-mediated and requires energy to move “uphill” against an electrical or pressure gradient.
Primary Active Transport
- Energy comes directly from the breakdown of ATP or some other high-energy phosphate compound.
- Examples:
- Na+/K+ pump found in all cells.
- Ca++ active transport in cell membrane and inside the cell.
- Active transport of H+ found in gastric glands of the stomach and distal and collecting tubules of the kidney.
- H+/K+ pump (proton pump at the stomach).
Secondary Active Transport
- Energy is derived secondarily from energy stored in the form of ionic concentration differences between the two sides of the membrane, created by primary active transport.
- Examples:
- Na+/glucose co-transport.
- Na+/amino acid co-transport.
Body Fluids
-
Extracellular fluid (ECF): fluid environment in which the cells live (fluid outside the cells), containing ions, O2, nutrients, and waste products.
- Includes:
- Plasma (inside blood cells)
- Interstitial fluid (around the cells)
- Includes:
- Intracellular fluid (ICF): fluid contained within all body cells, high in K+ and low in Na+. It contains protein with a negative charge.
- ICF:ECF ratio: 2:1, meaning that ICF accounts for 2/3 and ECF for 1/3 of total body water.
Homeostasis
- Maintenance of a relatively constant/stable internal environment (extracellular fluids).
- Maintaining a dynamic steady state in the internal environment.
- The internal environment remains relatively constant despite changes in the external environment.
- Stable does not mean rigid, values can vary within a narrow limit (normal physiological range).
- Essential for survival and function of all cells.
Factors Homeostatically Regulated
- Concentration of nutrients (e.g., glucose, O2, CO2, and waste products).
- Concentration of water, salt, and other electrolytes.
- pH.
- Blood volume and pressure.
- Body temperature.
Homeostatic Control Mechanisms
- Three components:
- Receptor: provides information about the stimuli.
- Control Center: tells what a particular value should be (called the set point).
- Effector: elicits responses that change conditions in the internal environment.
Negative Feedback Loops
- Sensor: monitors internal conditions, detects changes.
- Integrating Center (Controller): receives and integrates information.
- Effector: responds to changes, activity of effectors results in return of the condition to normal levels.
Movements Into and Out of the Cell
| Property | Simple Diffusion | Facilitated Diffusion | Active Transport |
|---|---|---|---|
| Requires special membrane protein | No | Yes | Yes |
| Highly selective | No | Yes | Yes |
| Uphill transport | No | No | Yes |
| Requires energy | No | No | Yes |
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the fundamental concepts of osmosis and osmotic pressure in this quiz. Understand how water movement influences cellular behavior and the impact of different saline solutions on human cells. Test your knowledge of hypotonic, hypertonic, and isotonic environments.
