Ch. 2: Homeostasis

Question 1

Normal range equals

Answer 1

Physiological tolerable range

Question 2

What is normal range?

Answer 2

Temporary loss in homeostasis in one or more variables is tolerable
Ex.) rise in blood glucose after eating a meal
Ex.)Elevated body temperature during exercise

Question 3

What kind of problems can result from chronic loss in homeostasis?

Answer 3

Type II Diabetes - blood level is high for a extended period of time
Heat stroke - if body temp stays elevated for a long period of time results in a heat stroke

Question 4

Homeostasis at each of the __________levels

Answer 4

Chemical 
Cellular
Tissue 
Organ
System
Organism

Question 5

What is 60% or our body mass made of?

Answer 5

Composed of fluid

Question 6

What is consisted up of the fluid compartments?

Answer 6

Intracellular (70%)

Extracellular (30%)

Question 7

What makes up the extracellular fluid?

Answer 7

Plasma- fluid portion of the blood

Interstitium- the area with a tissue between the cells

Question 8

How are VOLUME, TEMPERATURE, CHEMICAL CONTENT different?

Answer 8

Different between compartments and differences must be maintained for homeostasis

Question 9

What is homeostasis dependent on?

Answer 9

The dynamic exchange of fluid between compartments

Question 10

Why is extracellular fluid important?

Answer 10

Extracellular fluid serves as a means through which cells throughout the body can communicate with each other

Question 11

How do cells communicate with each other?

Answer 11

By releasing chemicals into the extracellular fluid

Ex.) growth factors, hormones, neurotransmitters

Question 12

What do the chemicals used for cell communication alter the activity of?

Answer 12

The cell that produced the chemical (autocrine)
Other cells that reside in the same tissue (paracrine)
Or cells in a different organ system (endocrine)

Question 13

Neurons release chemicals called

Answer 13

Neurotransmitters

Question 14

What are neurotransmitters?

Answer 14

Are chemicals se created by neurons that diffuse across a small gap to to target cell
Neurons use electrical signals too

Question 15

What are the 2 types of short range cell communication

Answer 15

Autocrine and paracrine

Question 16

What are 2 of the long range cell communication

Answer 16

Endocrine in the blood stream
Hormones are released by the endocrine glands into the blood
Only target cells with receptors for the specific hormones respond to that signal

Question 17

Why is fluid volume important?

Answer 17

Fluid volume influences the concentration of chemicals in the extracellular and intracellular fluid
Ex.) extra or intracellular goes down the concentration goes up
If you sweat too much loose Water so concentration is not as diluted
Ex.) extra or intracellular goes up the concentration goes down
If you drink too much then you pee a lot causing a decrease in solutes more watery

Question 18

Why is temperature important?

Answer 18

Temp of extra and intracellular fluid reflects the balance between heat production and heat loss

Question 19

What do enzymes control

Answer 19

Control chemical reactions and hence influence the concentration of chemicals
Regulate the speed of a reaction
Are sensitive to temperature
Once the enzymes slow down the body slows down bc temp gets to high

Question 20

What is the importance of concentration?

Answer 20

Influences the activity or function of cells

Question 21

What do the different set point values for the intra and extra cellular compartment illustrate?

Answer 21

Illustrate separate control mechanisms exist for maintaining 
Intracellular homeostasis (maintain temp)
    -Intrinsic local control mechanisms
Extracellular homeostasis (aid other organs/systems to maintain homeostasis )
    -extrinsic control mechanisms

Question 22

What is normal range?

Answer 22

Physiologically tolerable range for normal cell, tissue, organ, and organ system function
If the measurement is outside the normal range the body will not function properly

Question 23

What does the degree of oscillations provide?

Answer 23

Some indication of the relative importance of a variable to homeostasis
Ex.) small (pH)
Ex.)Large (glucose )

Question 24

What is feedback control?

Answer 24

Mechanisms that attempt to maintain the normal range during “normal” and “stressful” conditions
Ex.) fasting and disease

Question 25

What are the 2 types of feedback control?

Answer 25

Negative and positive feedback control

Question 26

What are the 2 types of negative feedback?

Answer 26

Simple negative feedback and antagonistic effectors

Question 27

What is positive feedback?

Answer 27

Same direction
Effector causes an amplification of the initial response
Ex.) contractions during child birth

Question 28

Are positive feedback mechanisms embedded in the negative feedback loop?

Answer 28

Yes and positive feedback accelerates the completion of negative feed back
Example is activation of blood clotting factors
Bleeding ->clotting factors ->clotting factors -> no bleeding
1 clotting factor leads to all the clotting factors to stop the bleeding
Domino effect
Positive feedback itself would lead to death
Positive feed back doesn’t happen by itself it happens with negative feedback

Question 29

What is Intrinsic feedback control?

Answer 29

A cell tissue/organ achieves homeostasis without the help of other physiological systems

• control mechanisms are built in
• Autocrine and Paracrine are release factors that maintain homeostasis of the cells within a organ or tissue

Question 30

What is extrinsic feedback control?

Answer 30

A cell/tissue/organ achieves homeostasis by relying on factors produced by other physiological systems (extrinsic factor)
Ex.)nervous system influence in the heart
Ex.)Insulin promoting glucose uptake by cells

Question 31

2 examples of extrinsic feedback control

Answer 31

Autonomic nervous system influence on cardiovascular system

Endocrine system influence on skeletal muscle

Question 32

What is simple negative feedback

Answer 32

Sensor -A cell that detects a rise in the internal environment (chemical signal)
Integrating center -another cell receives info from other senses and decides the appropriate response
Effector-brings about a change in the opposite direction
Sensor->Integrating center->effector

Question 33

What are 2 antagonistic effectors

Answer 33

Two simple negative feedback mechanism working together to maintain homeostasis of a variable/chemical
Effectors have opposing actions-
one or more effectors are pushing the variable in one direction and the other effector is pulling it in the opposite direction
Primary mechanism of homeostasis

Question 34

What does parasympathetic and sympathetic do in the autonomic nervous system?

Answer 34

Sympathetic increase the heart rate and parasympathetic decrease the heart rate

Question 35

What are the antagonistic effectors in homeostasis of blood glucose

Answer 35

Insulin-Decrease blood glucose

Glucagon- increases blood glucose

Question 36

True or false
The inability of numerous cells within a tissue to be able to maintain homeostasis can influence the function of not only the tissue that houses the cells but also the function of cells in other organ systems

Answer 36

True if you have problems with the heart you are going to have problems with a lot of other tissues and organs

Question 37

Can a set point be changed ?

Answer 37

Yes because for heart rate during endurance training the heart rate goes down and for body weight during pregnancy increase and blood pressure increases the body will adapt

Question 38

What is application of concepts?

Answer 38

Compare it to measured normal range

And see where the problem arises -homeostatic mechanisms not regulating properly

Question 39

When homeostasis goes wrong what happens

Answer 39

Secondary complications arise many problems

Question 40

What is homeostasis?

Answer 40

Maintenance of relatively constant conditions in the body
Conditions:
Volume
Temperature
Chemical content
Of fluid inside and outside of cells, tissues, and organs