Homeostasis - Foundations 1.2 08/10/17

Question 1

What are 5 examples of homeostasis in the body?

Answer 1

1. Body temperature
2. Blood volume
3. Body weight
4. Blood O2 levels
5. pH

Question 2

Definition of homeostasis

Answer 2

The body’s ability to maintain a relatively stable, constant condition in its internal environment

Question 3

Definition of equilibrium

Answer 3

No net change over time. Competing influences produce no net change.

Question 4

Definition of steady state

Answer 4

Supplied energy that keeps an individual system in its own balance (equilibrium) despite possibly being is non-equilibrium conditions w/ its environment

Question 5

Equation that relates steady state, equilibrium, and body temperature

Answer 5

Heat Production + Heat Gain = Heat Loss

Question 6

Definition of physiological gradients

Answer 6

A change w/ respect to distance of something that can be measured (think graph and axes)

Question 7

What 3 things do physiological gradients, in part, determine?

Answer 7

1. Thermal energy
2. Rate of movement of fluid
3. Ions and molecules

Question 8

Define pressure gradient

Answer 8

Pressure difference along a specified distance

Question 9

Body temp equation

Answer 9

Gradient = Ts - Ta /X

Question 10

Body temp equation in regards to thermal flux (Jt)

Answer 10

Jt = K(Ts - Ta)/X

Question 11

Blood pressure equation

Answer 11

Gradient = (P1 - P2)/X

Question 12

Gas gradient equation

Answer 12

Gradient = (PaO2 - PcO2)/X

Question 13

Are intracellular, interstitial, and blood osmotic pressures normally the same?

Answer 13

Yes; at 300 mOsm (milliosmoles)

Question 14

Hypertonic

Answer 14

Higher osmotic pressure

Question 15

Hypotonic

Answer 15

Lower osmotic pressure

Question 16

What does dehydration cause?

Answer 16

An increase in blood osmolarity, which causes the interstitial to shrink and become hypertonic relative to cells

Question 17

What is blood osmolality?

Answer 17

Ions, carbs, sugars, etc

Question 18

Define negative feedback

Answer 18

A response the body produces to allow the body to get back to its normal, set point

Question 19

Is negative feedback bidirectional?

Answer 19

Yes; meaning anything that goes below or above a set point for that process can activate negative feedback

Question 20

What are the negative feedback system components?

Answer 20

1. Controlled variable (BP, temp)
2. Feedback sensor (monitors controlled variable level)
3. Controller/comparator (controlled variable and set point compared, error signal determined)
4. Activator (physiological response to reduce deviation from set point)

Question 21

What are 5 examples of negative feedback control?

Answer 21

1. Body temperature
2. Blood pressure
3. Blood gases
4. Muscle movement
5. Thyroxin hormone

Question 22

Is arterial pressure under autonomic control?

Answer 22

Yes

Question 23

What increases arterial pressure?

Answer 23

Constriction of blood vessels

Question 24

Which nervous system stimulates the heart to constrict blood vessels?

Answer 24

Sympathetic

Question 25

Baroreceptor

Answer 25

Receptor that is sensitive to pressure (carotid)

Question 26

Chemoreceptors

Answer 26

Measure gas in the blood (arterial and medullary)

Question 27

Hypercapnea

Answer 27

High PCO2

Question 28

Muscle spindles

Answer 28

Muscle stretch receptors

Question 29

Positive feedback

Answer 29

A process by which deviation from the set point tends to promote even further deviation

Question 30

Cardiac Ischemia

Answer 30

Damage or disease in heart's major blood vessels

Question 31

Feedforward Mechanism

Answer 31

Controlled regulation for anticipation of a predicted outcome