Control of the Internal Environment/Physiological Overview - Chap 2

Question 1

What is the most basic (smallest) living unit of the body?

Answer 1

Cells

Question 2

What are the two physiological systems that allow for cellular communication within the body?

Answer 2

Nerves and Endocrine system are responsible for relaying the message.

Question 3

What is Negative Feedback? Give an example.

Answer 3

Definition - change in factor causes reaction to restore previous levels; the primary type of feedback used by the body.

Examples - thermo regulation, regulation of HR/BP, maintenance of blood glucose.

Question 4

What is Positive Feedback? Give an example.

Answer 4

Definition - Initiating stimulus cause more the same.

Example - Birth of a baby: when the fetus pushes against the cervix . then the brain stimulates the pituitary gland to secrete oxytocin. Oxytocin stimulate uterine contractions and pushed fetus toward cervix.

Question 5

What are the general components of a biological control system?

Answer 5

1. Sensor
2. Control Center
3. Effector Organ

Question 6

Does internal environment remain absolutely constant at rest?

Answer 6

No, “Dynamic constancy” = most physiological
variables vary around a set value

Question 7

What is Steady State?

Answer 7

not normal, but unchanging

Question 8

What is Homeostasis?

Answer 8

the body’s ability to
resist change in order to
maintain a stable, relatively
constant internal environment
during resting conditions