Fluid Comp And Homeostasis

Question 1

Name the four body fluid compartments.

Answer 1

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

Question 2

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

Answer 2

60%

Question 3

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

Answer 3

2:1

(2/3 TBW ICF)

(1/3 TBW ECF)

Question 4

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

Answer 4

Interstitial fluid.

Plasma.

Question 5

What % of ECF does interstitial fluid comprise?

Answer 5

80%

Question 6

What % of ECF does plasma comprise?

Answer 6

20%

Question 7

What separates the ICF from the ECF?

Answer 7

Cell membrane or plasma membrane.

Question 8

What is intracellular fluid comprised of? (3 examples)

Answer 8

Sodium.

Potassium.

Protein concentrations.

Question 9

The composition of ECF is similar to _______.

Answer 9

Seawater.

Question 10

What separates interstitial fluid from blood plasma?

Answer 10

Capillary wall.

Question 11

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?

Answer 11

Plasma proteins.

Question 12

What are plasma proteins important for?

Answer 12

Keeping fluid inside the cardiovascular system.

Question 13

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

Answer 13

Edema.

Question 14

Define homeostasis.

Answer 14

The relative constancy of the internal environment.

Question 15

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

Answer 15

Constant.

Fluctuates.

Normal range.

Question 16

Homeostasis is in a state of _______ _______.

Answer 16

Dynamic constancy.

Question 17

At rest, the inside of a cell is what?

Answer 17

Slightly negative.

Question 18

When activated, the inside of a cell becomes what?

Answer 18

Positive.

Question 19

When an activated cell becomes positive, it generates what?

Answer 19

An action potential (AP).

Question 20

Activation of a cell is largely dependent upon what?

Answer 20

Concentrations of various ions in the interstitial fluid.

Question 21

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

Answer 21

Initiates reactions.

To correct or minimize changes.

Question 22

Name 4 homeostatic control systems.

Answer 22

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

Question 23

How can you increase body temperature when it drops?

Answer 23

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

Question 24

What continuously senses core temperature of body?

Answer 24

Thermoreceptors.

Question 25

Where is sensor information sent?

Answer 25

Integrating center.

Question 26

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

Answer 26

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

Question 27

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

Answer 27

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

Question 28

Define negative feedback and give an example.

Answer 28

Counter action of an effect by its own influence.

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

Question 29

What is a reflex arc?

Answer 29

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

Question 30

List the steps of a homeostatic reflex arc.

Answer 30

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

Question 31

What is a stimulus?

Answer 31

A detectable change in controlled variable.

Question 32

What is a receptor?

Answer 32

The sensor on which a stimulus acts.

Question 33

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

Answer 33

Feedforward mechanism.

Anticipates changes to minimize fluctuations.

Question 34

Give an example of a feedforward mechanism.

Answer 34

Olfactory cues to turn on digestive system.

Question 35

Define positive feedback and provide an example.

Answer 35

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

Hormonal control of uterine contractions during childbirth.

Question 36

What do homeostatic responses rely upon?

Answer 36

Communication between cells to cause a response.

Question 37

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

Answer 37

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

Question 38

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

Answer 38

A chemical messenger secreted by endocrine cells.

Found in bloodstream.

Question 39

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

Answer 39

A chemical messenger released by a neuron.

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

Question 40

Define a paracrine agent.

Answer 40

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

Question 41

Define an autocrine agent.

Answer 41

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

Question 42

What characteristic of chemical messengers determines what we call them?

Answer 42

Where their endpoint location is.