Chapter 9

Question 1

Define negative feedback mechanisms

Answer 1

Primary mechanism of homeostasis; a stimulus triggers a response to maintain equilibrium

Example: Sweating

Question 2

What is positive feedback?

Answer 2

A response that increases the effect of any changes made to the system; usually does not result in homeostasis

Example: Childbirth

Question 3

What are the components of a negative feedback system?

Answer 3

Stimulus, Sensor, Integrator, Effector, Response

Each component plays a role in maintaining homeostasis.

Question 4

What is the role of the stimulus in a negative feedback mechanism?

Answer 4

Change in internal/external environment

Initiates the feedback process.

Question 5

What is the function of the sensor in a negative feedback mechanism?

Answer 5

Located in tissues and organs; sends a signal to the coordinating center when operating beyond normal limits

Detects changes in the environment.

Question 6

What is the purpose of the integrator in a negative feedback mechanism?

Answer 6

Control/processing center that compares existing conditions to optimal functioning conditions

Also known as set points.

Question 7

What does the effector do in a negative feedback mechanism?

Answer 7

Makes a response to restore normal balance if environmental conditions are outside the set point

Acts to correct deviations.

Question 8

Provide an example of a negative feedback mechanism.

Answer 8

Household thermostat: when room temperature moves away from the desired set point, the integrator activates an electrical effector

This returns the temperature to the set point.

Question 9

What are the three steps of urine formation?

Answer 9

Filtration, Reabsorption, Secretion

Each step occurs in specific regions of the nephron.

Question 10

Define filtration in the context of urine formation.

Answer 10

Movement of fluids from blood in the glomerulus to Bowman’s capsule through a selectively permeable membrane

First step of urine formation.

Question 11

What is reabsorption in the nephron?

Answer 11

Transfer of fluids from nephron into peritubular capillaries to return substances to the blood

Second step of urine formation.

Question 12

Define secretion in the urine formation process.

Answer 12

Transfer of fluids (wastes/toxins) from peritubular capillaries and interstitial fluid into nephron

Third step of urine formation.

Question 13

What is deamination?

Answer 13

Process used to break down amino acids for energy in excess protein intake

Involves removal of the amino group.

Question 14

What is the byproduct of deamination?

Answer 14

NH3 (ammonia)

Formed when the amino group is removed from the amino acid.