Homeostasis and Control Systems in Biology

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Questions and Answers

What is homeostasis in the human body?

The process of detecting stimuli through the nervous system

The ability to maintain stable internal conditions despite environmental changes (correct)

The tendency for body temperature to rise continuously

The process of chemical communication through hormones

Which component of a control system is responsible for determining the response to a stimulus?

Control Centre (correct)

Effector

Stimulus

Receptor

In the context of the bimetallic strip, what property causes it to bend when heated?

The temperature of the Bunsen burner

The uniform expansion of metals

The electrical current passing through

The different rates of expansion between metals (correct)

What type of feedback mechanism works to slow the original stimulus?

Negative feedback mechanism Signup and view all the answers

Which system communicates through electrical impulses to maintain homeostasis?

Nervous system Signup and view all the answers

In the airport example, what defines the stimulus?

The presence of the cell phone Signup and view all the answers

What role does the effector play in a control system?

Produces a change in response to the control centre's decision Signup and view all the answers

Which of the following is an example of a positive feedback mechanism?

Blood clotting process Signup and view all the answers

What role does oxytocin play during childbirth?

It stimulates nerve impulses to increase oxytocin production. Signup and view all the answers

What happens when the homeostatic balance in the body is disrupted?

It may result in disease. Signup and view all the answers

Which condition might Marge Simpson face due to low calcium intake from a dairy-free diet?

Osteoporosis Signup and view all the answers

What could potentially happen if intravenous solution is administered too rapidly?

The body might not be able to handle the rapid change. Signup and view all the answers

Which of the following is a possible complication of intravenous therapy?

Kinks in the tubes causing blockage. Signup and view all the answers

During nursing, what is crucial to ensure effective fluid transport?

Effective communication during change-overs. Signup and view all the answers

What can be a negative outcome of forgetting to set the drip factor correctly?

Incorrect administration rate of fluids. Signup and view all the answers

What is a potential risk when administering intravenous fluid to a patient?

Fluid overload potentially harming patient health. Signup and view all the answers

What primarily differentiates facilitated diffusion from simple diffusion?

Facilitated diffusion employs specific channels or carriers for transport. Signup and view all the answers

Which factor does NOT affect the rate of diffusion?

Type of molecule Signup and view all the answers

What type of process does the sodium-potassium pump represent?

Active transport process Signup and view all the answers

In the context of dialysis, what happens to urea in the dialysis machine?

Urea diffuses into the clean dialysis fluid. Signup and view all the answers

Which statement about leakage channels is true?

They are constantly open and allow a constant flow. Signup and view all the answers

What characterizes the movement of glucose across the plasma membrane?

Glucose requires facilitated diffusion through specific channels. Signup and view all the answers

How does the sodium-potassium pump contribute to cell function?

It maintains the cell's resting membrane potential. Signup and view all the answers

Which of the following accurately describes osmosis?

The movement of water across a semipermeable membrane. Signup and view all the answers

What is the main driving force for water movement in osmosis?

Concentration differences of solute Signup and view all the answers

How does hydrostatic pressure affect osmosis?

It prevents water from moving into the cell Signup and view all the answers

What occurs when solutions of different solute concentrations are separated by a selectively permeable membrane?

Only water moves to equalize solute concentrations Signup and view all the answers

What is the effect of mannitol when introduced into blood?

It increases osmolarity and draws water out of cells Signup and view all the answers

What happens to animal cells in a hypertonic solution?

They shrink due to water loss Signup and view all the answers

What determines the extent of water concentration decrease when solute concentration increases?

Number of solutes in a solution Signup and view all the answers

What is meant by the term 'isotonic' in the context of cell fluid balance?

Both sides of the membrane have equal osmotic pressure Signup and view all the answers

Which statement is true regarding osmotic pressure?

It prevents further water entry into a cell Signup and view all the answers

What is the effect of a hypertonic solution on a cell?

Cells will shrink. Signup and view all the answers

In which scenario is water moving out of cells beneficial?

Cerebral edema. Signup and view all the answers

What characterizes isotonic dehydration?

Loss of both electrolytes and water. Signup and view all the answers

How does filtration work in the context of cellular fluid movement?

It is facilitated by hydrostatic pressure. Signup and view all the answers

What happens to a cell in a hypotonic solution?

It will swell and may burst. Signup and view all the answers

What causes hypertonic dehydration?

Loss of body water faster than electrolytes. Signup and view all the answers

What is the consequence of isosmotic fluid loss?

Homeostasis usually restores the balance. Signup and view all the answers

What occurs when cells are subjected to an isotonic solution?

Cells experience no change in shape. Signup and view all the answers

What is a saturated solution?

A solution that has dissolved all solutes at a specific temperature. Signup and view all the answers

What defines a supersaturated solution?

A solution that contains more solute than a saturated solution. Signup and view all the answers

What is molarity a measure of?

The concentration of a solution in moles per liter. Signup and view all the answers

What is the role of plasma membranes in cells?

Separate the cell from the surrounding extracellular fluid. Signup and view all the answers

Which of the following best describes colloidal solutions?

Solutions where solutes form large, non-diffusible molecules. Signup and view all the answers

What is a characteristic of passive transport processes?

They happen without the expenditure of cell energy. Signup and view all the answers

What could be a consequence of excessive uric acid in the kidneys?

Formation of kidney stones. Signup and view all the answers

Which component is NOT part of the plasma membrane structure?

Nucleic acids. Signup and view all the answers

Study Notes

Homeostasis

Homeostasis is the ability of the human body to maintain relatively stable internal conditions despite environmental changes.

Control Systems

Nervous System: Communicates via electrical impulses.
Endocrine System: Communicates through chemical messengers.

Components of a Control System

Stimulus: A change that triggers a response.
Receptor: Detects the stimulus.
Control Center: Determines the response.
Effector: Produces a change to counteract the stimulus.

Example: Airport Security

Stimulus: Forgetting a phone in the pocket.
Receptor: The alarm in security.
Control Center: The customs agent.
Effector: The agent's response (checking the matter).

Control System Feedback Loop

Input: Information sent along an afferent pathway to a receptor (sensor).
Receptor (sensor): Detects changes in a variable.
Control center: Determines the response.
Output: Information sent along an efferent pathway to an effector.
Effector: Produces a change to influence that variable.
Response: The magnitude of the stimulus is modified by the response of the effector.
Homeostasis: The variable returns to its set point.

Bimetallic Strips

A bimetallic strip is made from iron and aluminum.
The metals expand and contract at different rates.
When heated, the strip bends.
Used in heaters, fire alarms, and other electrical equipment.

Example: Thermostat

Stimulus: Rising room temperature.
Receptor (sensor): Thermometer in the thermostat.
Control Center: Thermostat.
Effector: Heater.
Response: Heater is turned on to lower the temperature.
Homeostasis: Room temperature returns to the set point.

Control Mechanisms

Negative Feedback: Response is in the opposite direction of the original stimulus.
- Example: Regulating body temperature.
Positive Feedback: Response is in the same direction as the original stimulus.
- Example: Blood clotting.

Negative Feedback - Blood Glucose

Stimulus: Rising blood glucose.
Receptor: Insulin-secreting cells in the pancreas.
Control Center: Pancreas.
Effector: Cells of the body take up glucose, the liver stores glucose as glycogen.
Response: Release of insulin into the blood.
Homeostasis: Blood glucose returns to the normal range.

Homeostatic Imbalance

When the normal balance of the body is not maintained, disease may be the result.

Solutions

Solution: Mixture of two or more substances.
Solute: Substance dissolved in a solution.
Solvent: Liquid in which the solute is dissolved. (usually water)

Types of Solutions

Unsaturated Solution: A solution that hasn't reached its saturation point (solvent can still dissolve solute without exceeding this point.)
Supersaturated Solution: Contains more solutes than a saturated solution. (Precipitate can form)
Saturated Solution: A solution that has dissolved all the solute possible at that temperature.
Colloidal Solutions: Solutes join to form large, non-diffusable molecules (like cytosol, spinal fluid, blood).

Osmosis

The movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration.

Osmolarity

Total concentration of all solute particles in a solution.

Tonicity

Describes the ability of a solution to cause a cell to gain or lose water.
- Isotonic: Contains the same concentration of solutes as the cell.
- Hypertonic: Contains a higher concentration of solutes than the cell.
- Hypotonic: Contains a lower concentration of solutes than the cell.

Filtration

Process that forces water and solutes through a membrane due to hydrostatic pressure, from area of high to low pressure
Non-selective and passive

Active Transport

Requires energy (ATP) to move solutes against their concentration gradient.
E.g. Sodium-potassium pump.
- Moves Na+ out and K+ into cells.

Muscle Cells and Calcium

Muscle cells pump calcium ions out of the cell to maintain a lower concentration when resting.
Calcium influx into the cell causes contraction.

Dehydration Types

Hypertonic: Water lost faster than electrolytes.
Isotonic: Loss of both water and electrolytes.
Hypotonic: Loss of electrolytes faster than water.

Summary

The provided texts describe aspects of homeostasis, control systems, various transport mechanisms (active and passive), and the effects of different solutions on cells, all key concepts in biology.

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Description

This quiz explores the concept of homeostasis and the control systems in the human body. It covers the roles of the nervous and endocrine systems, the components of control systems, and provides an example using airport security. Test your understanding of how feedback loops function in maintaining internal stability.