3. Homeostasis Flashcards

1
Q

Temperature of human environments

A

Outside: -10 and +40 C
Inside: 37 C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

PO2 of human environments

A

Outside: 160 mmHg
Inside: PaO2 95mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

PCO2 (breathing) of human environments

A

Outside: 0.23 mmHg
Inside: 40 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Water of human environments

A

Outside: 0-90 g/kg of air
Inside: 600 g/kg tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

pH of Human environments

A

Outside: ?/variable
Inside: pH 7.4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Ability of the body to maintain a relatively stable internal environment despite external variances

A

Homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The study of the various mechanisms that maintain homeostasis

A

Physiology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Water distribution
40% body weight; 28L
2/3 of total body water

A

Intracellular water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Water distribution
20% body weight; 14L
1/3 of total body water

A

Extracellular water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Water distribution
Part of extracellular
15% body weight; 10.5L

A

Interstitial fluid and lymph water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Water distribution
Part of extracellular water
5% body weight; 3.5L

A

Plasma (blood) water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Water distribution
60% body weight; 42L

A

Total body water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Gender with 60% water

A

Men
More testosterone leads to less body fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Gender with 50% water

A

Women
More body fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ionic composition of ICF and ECF

Intracellular: 14 Extracellular: 140

A

Na+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ionic composition of ICF and ECF

Intracellular: 120 Extracellular: 4

17
Q

Ionic composition of ICF and ECF

Intracellular: 1x10^4 (very low) Extracellular: 2.5

18
Q

Ionic composition of ICF and ECF

Intracellular: 20 Extracellular: 0.8

19
Q

Ionic composition of ICF and ECF

Intracellular: 10 Extracellular: 105

20
Q

Ionic composition of ICF and ECF

Intracellular: 10 Extracellular: 24

21
Q

Ionic composition of ICF and ECF

Intracellular: 7.1 Extracellular: 7.4

22
Q

Ionic composition of ICF and ECF

Intracellular: 290 Extracellular: 290

A

Osmolarity

23
Q

Cerebrospinal, synovial, and pleural fluids
Different from Plasma

A

Interstitial fluids

24
Q

Maintenance of a state that does not change with time, and energy expenditure may be necessary
Eg. ICF [Na+] < ECF [Na+] and concentrations are maintained at a set level balanced over time → requiring energy

A

Steady state
Na/K - ATPase pump
Solutes are in a steady state (body expends effort and energy to maintain uneven solute concentrations to allow optimal function)

25
Implies that two compartments have the same amount of free energy so there is no net energy transfer between two compartments.
Equilibrium Water is in equilibrium between ICF and ECF due to solute concentration difference
26
Homeostatic Mechanisms Physiological parameter being controlled
Controlled Variable
27
Homeostatic Mechanisms Receptor type (sense organ) that detects changes in the controlled variable
Sensor
28
Homeostatic Mechanisms Integration center that analyzes data from the sensor and compares to set point
Integrator/Comparator
29
Homeostatic Mechanisms “Normal” values predetermined but influenced by environmental adaptations
Set Point
30
Homeostatic Mechanisms Nerve pathways, hormones, cells, tissues that carry out the response needed to restore homeostasis
Effectors
31
Set Point deviation Since daily routine is so variable set points often vary between active (day) and passive (night) times i.e. K+ excretion is greater during the day than at night – more ingested during the day
24 hour cycle Circadian rhythm
32
Set Point deviation Changes in external environment i.e. Acclimation → one goes to live at high altitudes, set point for PO2 levels change
Environmental Changes
33
Set Point Deviations During infections i.e. Fever - increase in body temperature is an adaptation of set-point to minimize viral replication i.e. Plasma iron concentration decreases significantly to deprive bacteria of iron needed for replication
Protective Response
34
Set Point Deviations As disease progresses, set point elevates more and more i.e. Atheramatous plaques in blood vessels increase BP and resetting of BP set point → blood pressure continues to increase chronically as cardiovascular disease progresses
Aging or Pathological changes
35
The more vital the parameter to be controlled the more homeostatic mechanisms needed to control it • Complex interplay may exist among various control systems • If one mechanism fails then others can still maintain that parameter around set point → multiple control systems • Often there is more than 1 control mechanism as a back-up
Redundancy Example: Blood hemorrhage: Brain is Cardiovascular control center. Compares BP to set point and adjusts vascular tone and cardiac output accordingly.
36
Where set-point of some variables may be altered in order to maintain others i.e. changes in skin blood vessel diameter during exercise.
Homeostatic Hierarchy During exercise, outflow increases causing vasoconstriction, helps maintain BP. With strenuous exercise, temp control in hypothalamus inhibits sympathetic outflow to skin blood vessels causing vasodilation and heat loss During maximum exercise, the need to maintain blood pressure takes priority over maintaining body temp, blood vessels constrict again.
37
Deficient Homeostatic Mechanisms In many disease processes the normal negative feedback mechanisms may initially work to the benefit of the individual but as the disease progresses then normal compensatory responses fail and the normal negative feedback mechanisms are overtaken by positive feedback loops with disastrous consequences.
i.e. In chronic heart failure cardiac output falls and the body responds by retaining fluid. The retention of fluid increases the work load of the heart thus eventually making it even more likely to fail.