Fluid Comp And Homeostasis Flashcards

1
Q

Name the four body fluid compartments.

A

1) Intracellular fluid (ICF)
2) Extracellular fluid (ECF)
3) Interstitial fluid
4) Plasma

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2
Q

How much of the body’s total body weight is comprised of water?

A

60%

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3
Q

Of the total body water (TBW), what is the ratio of ICF to ECF?

A

2:1

(2/3 TBW ICF)

(1/3 TBW ECF)

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4
Q

Extracellular fluid (ECF) is comprised of _______ and ________.

A

Interstitial fluid.

Plasma.

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5
Q

What % of ECF does interstitial fluid comprise?

A

80%

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6
Q

What % of ECF does plasma comprise?

A

20%

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7
Q

What separates the ICF from the ECF?

A

Cell membrane or plasma membrane.

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8
Q

What is intracellular fluid comprised of? (3 examples)

A

Sodium.

Potassium.

Protein concentrations.

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9
Q

The composition of ECF is similar to _______.

A

Seawater.

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10
Q

What separates interstitial fluid from blood plasma?

A

Capillary wall.

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11
Q

Both plasma and interstitial fluid contain similar molecules/ions (I.e. Na, Ca, K). What is the one component plasma contains that interstitial fluid contains very little of?

A

Plasma proteins.

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12
Q

What are plasma proteins important for?

A

Keeping fluid inside the cardiovascular system.

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13
Q

What is it called when there is too much interstitial fluid?

A

Edema.

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14
Q

Define homeostasis.

A

The relative constancy of the internal environment.

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15
Q

In homeostasis, variables do not stay _______ and constantly ________ around a ________ ________.

A

Constant.

Fluctuates.

Normal range.

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16
Q

Homeostasis is in a state of _______ _______.

A

Dynamic constancy.

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17
Q

At rest, the inside of a cell is what?

A

Slightly negative.

18
Q

When activated, the inside of a cell becomes what?

A

Positive.

19
Q

When an activated cell becomes positive, it generates what?

A

An action potential (AP).

20
Q

Activation of a cell is largely dependent upon what?

A

Concentrations of various ions in the interstitial fluid.

21
Q

What does the body do in response to changes in the ECF composition? Why?

A

Initiates reactions.

To correct or minimize changes.

22
Q

Name 4 homeostatic control systems.

A

1) Ions, pH
2) Fluids
3) Blood sugar
4) Body temperature

23
Q

How can you increase body temperature when it drops?

A

1) Need a sensor or sensors
2) Need an integrating center to compare against a set point
3) Need effectors

24
Q

What continuously senses core temperature of body?

A

Thermoreceptors.

25
Q

Where is sensor information sent?

A

Integrating center.

26
Q

Where is the integrating center located and what does it do?

A

The hypothalamus and it compares variables to a set point. It then will produce changes in effectors to adjust for deviation from set point.

27
Q

What are some examples of effector response to decreased body temperature?

A

1) Constriction of blood vessels
2) Curling up via voluntary muscles
3) Shivering (general muscle activity)

28
Q

Define negative feedback and give an example.

A

Counter action of an effect by its own influence.

When body temperature drops, the body will try to warm back up.

29
Q

What is a reflex arc?

A

A biological control system that directly links a stimulus to its response.

30
Q

List the steps of a homeostatic reflex arc.

A

1) Stimulus
2) Receptor
3) Afferent pathway
4) Integrating center
5) Efferent pathway
6) Effector
7) Response

31
Q

What is a stimulus?

A

A detectable change in controlled variable.

32
Q

What is a receptor?

A

The sensor on which a stimulus acts.

33
Q

Negative feedback typically induces a lag time, therefore a ______ ______ is needed. What does this mechanism do?

A

Feedforward mechanism.

Anticipates changes to minimize fluctuations.

34
Q

Give an example of a feedforward mechanism.

A

Olfactory cues to turn on digestive system.

35
Q

Define positive feedback and provide an example.

A

When a stimulus initiates an amplification of its effect by own influence.

Hormonal control of uterine contractions during childbirth.

36
Q

What do homeostatic responses rely upon?

A

Communication between cells to cause a response.

37
Q

Communication between cells happens using different messengers. Name the 4 broad types.

A

1) Hormones
2) Neurotransmitters
3) Paracrine agents
4) Autocrine agents

38
Q

Define a hormone and it’s location in the body.

A

A chemical messenger secreted by endocrine cells.

Found in bloodstream.

39
Q

Define a neurotransmitter and it’s location in the body.

A

A chemical messenger released by a neuron.

Affects muscles, glands, and nerves. Travels synaptic cleft.

40
Q

Define a paracrine agent.

A

A chemical messenger released by a cell that acts on nearby cells.

41
Q

Define an autocrine agent.

A

A chemical messenger released into the interstitial fluid that acts upon the cell that secreted it.

42
Q

What characteristic of chemical messengers determines what we call them?

A

Where their endpoint location is.