Chapter 1 - Guyton

Question 1

Primary constituents of intracellular fluid.

Answer 1

potassium, magnesium, phosphate

Question 2

All of the blood in circulation passes through entire circulatory circuit in how long?

Answer 2

1 minute at rest, 6 times a minute when extremely active

Question 3

How does the baroreceptor system work to control arterial blood pressure?

Answer 3

baroreceptors in the walls of the bifurcation region of the carotid arteries of the neck and in the arch of the aorta in the thorax are stimulated by the stretch of the arterial wall and send impulses to the medulla to inhibit the vasomotor center resulting in diminished pumping activity and dilation of peripheral blood vessels

Question 4

Most control systems of the body act through which mechanism?

Answer 4

negative feedback

Question 5

Examples of negative feedback?

Answer 5

carbon dioxide regulation, arterial-pressure regulating mechanisms

Question 6

What is “gain” of a control system?

Answer 6

the degree of effectiveness with which a control system maintains constant conditions (equal to correction/error)

Question 7

What is positive feedback and why does it lead to instability?

Answer 7

initiating stimulus causes more of the same, think of blood loss–>arterial pressure falls–>flows to heart through coronary vessels diminishes–>more weakness of heart–>death

Question 8

Examples of healthy positive feedback.

Answer 8

blood clotting, uterine contractions, nerve signals (action potentials)

Question 9

What is feed-forward control in muscle contraction?

Answer 9

sensory nerve signals from the moving parts apprise the brain whether the movement is performed correctly and if not, corrects the next movement (adaptive control)