Chapter 1 Into To Physiology

Question 1

What is Physiology?

Answer 1

In the simplest terms:

-Study of the normal functioning of a living organism and its component parts

Question 2

How does the body, organs or tissues operate?

Answer 2

They operate via mechanisms.

Question 3

How are the mechanisms of the body determined?

Answer 3

Determined from experimental evidence or pathophysiology.

Question 4

What is used to validate a mechanism of the body, organ, or tissue?

Answer 4

Scientists use progressive steps in order to test the validity of a hypothetical mechanism called hypothesis testing

Question 5

What are the steps of Hypothesis Testing?

Answer 5

Observe a phenomenon
Formulate a hypothesis
Test the hypothesis (experimentally)
Analyze the results —> Does the results negate or support the hypothesis

Question 6

Why do we use the scientific method to validate mechanisms?

Answer 6

We can describe physiologic processes based on laws governing chemistry, biology and physics.

Question 7

What are the two groups that are used to test hypotheses?

Answer 7

Control group

Experimental group

Question 8

Who or what is the control group in an experiment?

Answer 8

Not subject to challenge/testing condition.

-usually given a placebo.

Question 9

What defines the experimental group of an experiment?

Answer 9

They ARE subject to challenge/testing condition

-this is the group where a variable is changed. e.g. They are given the specific drug that is being tested.

Their response is compared to the control.

Question 10

What causes variability in the samples during experiments?

Answer 10

There are always differences between the subjects this is referred to as variance

Question 11

How do you limit the effects of variance during an experiments?

Answer 11

Sampling of large populations limits the effects of variance

Question 12

What is the purpose of testing a mechanism or system?

Answer 12

Once we impose a “challenge” upon a biological system, we can then observe how the system or mechanism responds

Question 13

What is the independent variable in an experiment

Answer 13

It’s the variable that is being changed and its graphed on the x-axis.

Question 14

What is the Dependent Variable?

Answer 14

Variable being measured as it changes in response to the challenge

-Graphed on the Y-axis

Question 15

What is the importance of Physiology Research?

Answer 15

Basic (primary) research provides us an understanding of physiology processes.

-from an intellectual standpoint, all research contributes to our basic Knowledge

Question 16

We also preform physiology research because or what? And what is the term for this?

Answer 16

Clinical importance

-termed Translational Research

Question 17

What are the two models used in Translational research

Answer 17

-in vivo, and in vitro

Question 18

What is considered “in vivo” research?

Answer 18

Uses whole animal models. Usually does not include human models but it can

Question 19

What is considered ‘in vitro” research?

Answer 19

Uses tissue, cell cultures. More recently uses computer models

Question 20

What is Homeostasis?

Answer 20

It’s the maintenance of the relative constancy of the internal environment

Particular parameters are monitored and regulated

Maintained with a narrow range called a “set point”

Question 21

What is referred to as the internal environment during Homeostasis?

Answer 21

Extracellular fluid (plasma + interstitial fluid)

Question 22

What are some of the Homeostatically Regulated variables?

Answer 22

Arterial pH
Bicarbonate
Sodium
Calcium
Oxygen content
Urea
Amino acids
Totally Lipids
Glucose

Question 23

Define Negative Feedback Loop

Answer 23

A homeostatic feedback loop designed to keep the system at or near a set point.

Serve to maintain Homeostasis

It’s a response that counteracts a disturbance in the system.

Question 24

What are the components of a negative feedback loop?

Answer 24

A stimulus causes a disturbance—> sensor picks up the change—> input signal travels via the afferent pathway to—> integrating center—> output signal travels via the efferent pathway—>target or effector—> a response takes place

When the disturbance has been altered back within the homeostatic set point the negative feedback loop shuts of the response

Question 25

Give an example of a negative feedback loop

Answer 25

Lying down to standing up fast cause the blood pressure to drop (stimulus)—>blood pressure receptors pick up on this change, they are the (Sensors) —>sensor sends input signal via the afferent pathway to the Integrating center —> output signal via the Efferent pathway signals the heart to increase its rate, which results in a rise in blood pressure.

The negative feedback pathway stops when the blood pressure has come back within the set range.

Question 26

What is Antagonistic Control?

Answer 26

Some homeostatic parameters are maintained by two or more regulators with OPPOSING effects.

E.g. Blood glucose can go up or down having different effects which will cause the body to either raise insulin or decrease insulin causing an increase or decrease to blood glucose.

Question 27

Is a positive feedback loop homeostatic?

Answer 27

No a positive feedback loop is not homeostatic. The response reinforces the stimulus rather than decreasing or removing it.

Question 28

Give an example of a positive feedback loop is?

Answer 28

It involves the hormone control of uterine contractions during childbirth.

When the baby is ready to be delivered, it drops lower in the uterus and it begins to put pressure on the cervix. The pressure on the cervix send the signal via afferent pathway to the brain to cause the release of oxytocin, which causes the uterus to contract and push the baby out.

Not until this stretch from the cervix stops, after the deliver of the baby, the brain will not shut off the oxytocin. Once the stretch is gone the positive feedback loop will then stop

Question 29

When will a positive feedback loop stop?

Answer 29

Only when the stimulus is removed or an outside source intervenes