Physio Lab Exam

Question 1

Define adsoprtion

Answer 1

binding of molecules to surface of a
substance

Question 2

experimental design for powerphys Effect of Dietary Fiber on Transit Time & Bile for experiment #1 and #2

Answer 2

Effect of Dietary Fiber on Transit Time
Dependent Variable: number of radiopaque markers in GI tract
Independent Variable: amount and type of fiber in meal
Controlled Variables: calories in meal nutrients in meal

Effect of Dietary Fiber on Bile Acid Adsorption
Dependent Variable: amount of bile acids in solution
Independent Variable: amount of fiber in meal
Controlled Variables: moisture in meal size of meal particles calories and nutrients in meal

Question 3

What is the difference between a monosynpatic and polysynaptic reflex? What role does an interneuron play in polysynaptic reflexes?

Answer 3

Monosynaptic Reflex
* Simplest of all reflexes
* Just one synapse; no interneuron
* Fastest of all reflexes
* Stretch reflexes

Polysynaptic Reflex
* More common type of reflex
* One or more interneurons are part
of the pathway
* Withdrawal reflexes
* Interneurons signal the motor
neuron to contract muscle involved

Question 4

What are the expected (normal) responses of the following reflex tests?
Patellar (knee jerk), calcaneal (ankle jerk, achilles), plantar reflex, biceps reflex, triceps reflex

Answer 4

patellar:
response 1: quadriceps contracts, swinging lower leg
response 2: hamstring stays relaxed, allowing extension of leg

calcaneal:
foot should jerk toward the plantar surface

plantar:
plantar flexion of the big toe; often there is also flexion and adduction of the other toes

biceps:
flexion of the forearm. You will feel the biceps tendon contract if the biceps reflex is stimulated by the tap on the brachioradialis tendon

triceps:
contraction of the triceps muscle (elbow extension)

Question 5

Review the steps of a reflex arc and apply these steps to each of the stretch reflexes we tested during lab.

Answer 5

reflex arcs have 5 components:
1. Receptor at the end of a sensory neuron reacts to a stimulus.
2. Sensory neuron conducts nerve impulses along an afferent pathway towards the CNS
3. Integrating center consists of one or more synapses in the CNS.
4. Motor neuron conducts a nerve impulse along an efferent pathway from the integrating center to an effector.
5. Effector responds to the efferent impulses by contracting (if the effector is a muscle fiber) or secreting a product (if the effector is a gland).

Question 6

Review the two-point discrimination test. What did we measure here? What does this indicate?

Answer 6

• Receptive fields can be measured by seeing at what distance a person can perceive two separate points of touch
• Measures tactile acuity (sharpness of touch
  perception)

Question 7

Which areas of the body are the most sensitive to touch? Least? Relate the size of the two-point threshold on different areas of the body to touch receptor density and receptive field size

Answer 7

Smaller receptive fields will have greater acuity but lower sensitivity.
As you increase the size of a receptive field the acuity decreases and the sensitivity increases.
The advantage of this is you can have high sensitivity receptive fields to detect low intensity stimuli and you can have high acuity receptive fields to make out fine details.

Question 8

cutaneous thermoreceptors

Answer 8

Cold Receptors – free dendritic endings
* There are many more receptors that respond to cold
than to hot
* Located in the upper dermis
* Stimulated by cold and inhibited by warm
* The temperature range of response is 8 to 28°C
* Warm Receptors
* Located deeper in the dermis
* Excited by warming and inhibited by cooling
* Different from receptors that detect painful heat

Question 9

What are the various components of blood?

Answer 9

Plasma
Fluid portion

Cellular elements
Cells and cell fragments

Centrifuged blood
Plasma (top layer)
Buffy coat (middle)
Made up of platelets and leukocytes
Red blood cells (bottom layer)

Hematocrit (Hct)
The percentage of red blood cells in the total

sample
Males
~47%
Females
~42%

Question 10

characteristics of red blood cells

Answer 10

Transports oxygen from the lungs to the cells of the
body
 Transports carbon dioxide from body cells to the lungs
 Contains hemoglobin - oxygen carrying protein
 Biconcave shape gives increases surface area to enhance
diffusion
 Simple structure
Strong, flexible plasma membrane
 No nucleus
Extra room for hemoglobin
 Anaerobic metabolism
Don’t use the oxygen that they transport

Question 11

How did hemoglobin and hematocrit levels change at a higher elevation?

Answer 11

Hematocrit and hemoglobin increased after training at high altitudes for 2 months

hematocrit: the ratio of the volume of red blood cells to the total volume of blood.

hemoglobin: red protein responsible for transporting oxygen in the blood of vertebrates

Question 12

Blood typing
What determines a person’s blood type?
Who can donate to whom?
Who can receive from whom?
Define agglutination

Answer 12

Antigens
 A = Type A blood
 B = Type B blood
 A and B = Type AB blood
 Neither antigen A nor B =
Type O blood

O can donate to A, B, AB, O
A can donate to A and AB
B can donate to B and AB
AB can donate to AB

O can receive from O
A can receive from A, O
B can receive from B, O
AB can receive from A, B, AB, O

Agglutination
* Clumping of cells
* Leads to rupture of the
erythrocyte
o Can cause kidney damage

Question 13

What causes hemolytic disease of the newborn? How can this be prevented?

Answer 13

-caused by Rh incompatibility
-can be prevented if the mother is tested during pregnancy. If needed, she is given a shot of a medicine called RhoGAM at certain times during and after her pregnancy.

Question 14

What role do enzymes play in the body?

Answer 14

biological catalysts that:
* Increase the rate of a reaction
* Are not changed by the reaction (so can be used again)
* Do not change the nature of the reaction–the reaction could have occurred
without the enzyme, just much slower
* Lowers the activation energy of the reaction

Question 15

substrate, active site, allosteric site, optimal environment

Answer 15

substrate- reactants
active site- Specific region on enzyme for substrate binding- The substrate binds to the enzyme by interacting with amino acids in the binding site
allosteric site- a site that allows molecules to either activate or inhibit (or turn off) enzyme activity
optimal environment- environment that yields most products

Question 16

What enzyme did we study in this simulation? What substrate does it act upon? What are the products formed?

Answer 16

-sucrase
-acts on sucrose
-glucose and fructose

Question 17

Compare and contrast the lock-and-key model to the induced-fit model

Answer 17

lock and key: they fit into the active site like a key to a lock
induced fit: initial fit is not exact but will change as the substrate moves into the
active site

Question 18

What is the role of a cofactor and coenzyme?

Answer 18

cofactor:
Most enzymes need additional small
molecules to become completely
active
* Cofactors are metal ions such as, Ca2+,
Mg2+, Mn2+, Cu2+, Zn2+ and
selenium
* Cofactors help form the active site
through a conformational change of
the enzyme or help in enzyme-substrate binding

coenzyme:
Coenzymes are organic molecules derived from water-soluble
vitamins such as niacin and riboflavin
* They transport hydrogen atoms and other small molecules between
enzymes

Question 19

What factors influence enzyme activity and how? What does it mean when an enzyme becomes saturated

Answer 19

temperature, pH, substrate concentration,
Saturated means that every enzyme in the solution is being used
* Adding more substrate will
not increase the rate of the
reaction

Question 20

What is the difference between competitive vs. noncompetitive inhibition?

Answer 20

The competitive inhibitor binds to the active site and prevents the substrate from binding there. The noncompetitive inhibitor binds to a different site on the enzyme; it doesn’t block substrate binding, but it causes other changes in the enzyme so that it can no longer catalyze the reaction efficiently.

Question 21

What is end product inhibition?

Answer 21

the final product in a series of reactions inhibits an enzyme from an earlier step in the sequence.

Question 22

What are the best practices to follow when creating a graph?

Answer 22

-Figure legend
-Y-axis starts at 0. Labeled w/ units
-Color may not be necessary
-Remove default Excel title
-Standard Deviation
-Labeled columns
-error bars

Question 23

Which graphs must always start at 0 on the Y-axis? Which do not need to start at 0?

Answer 23

bar graphs should start at 0 while line and scatter plots do not need to

Question 24

When is it appropriate to make a bar graph vs. scatterplot vs. line graph. Be able to decide this if given sample data.

Answer 24

A Line Chart is ideal for showing growth rates or trends at even intervals.

A Scatter Plot works best in displaying relationships between varying variables.

Bar graphs are used to compare things between different groups or to track changes over time

Question 25

On what type of graph should we include a regression line?

Answer 25

scatterplots

Question 26

When should a paired vs. unpaired t-test be used

Answer 26

If you have one and the same sample that you survey at two points in time, you use an paired t-test.
If you want to compare two different groups, whether they come from one sample or two samples, you use an unpaired t-test.

Question 27

variable

Answer 27

any factor that can be manipulated, controlled, or measured in
an experiment

Question 28

independent variable

Answer 28

variable being manipulated/changed

Question 29

dependent variable

Answer 29

affected by the manipulation of independent variable, outcome, what we are measuring

Question 30

Controlled variables/constants

Answer 30

all other variables held constant

Question 31

control group

Answer 31

parallel set up that uses the same materials, but independent variable is either eliminated or set at a standard value; what we use as a
comparison

Question 32

experimental group

Answer 32

the group in a scientific experiment where the experimental procedure is performed

Question 33

trials

Answer 33

A trial is an individual instance of an experiment used to test different variations of the experiment settings

Question 34

replication

Answer 34

repeating a study’s procedure and observing if the prior findings repeat in similar conditions

Question 35

randomization

Answer 35

the process by which participants in clinical trials are assigned by chance to separate groups that are given different treatments or other interventions.

Question 36

placebo

Answer 36

an inactive substance that looks like the drug or treatment being tested.

Question 37

steps of the scientific method

Answer 37

1. observation
2. hypothesis
3. experimentation
4. results
5. conclusions

Question 38

difference between a hypothesis and prediction?

Answer 38

hypothesis: Educated guess, proposed explanation for phenomenon based
on observations and existing knowledge
* Must be testable and falsifiable

prediction: A prediction is the outcome you would observe if your hypothesis were correct
* Predictions often written in If X…, then Y… statement;

Question 39

How do you distinguish between credible versus non-credible sources of information?
What are some examples of each?

Answer 39

• Credible sources are ones the reader can
  trust
• Journals by authors who are experts in their
  field
• Websites from credible institutions (Mayo
  Clinic, Universities, .edu, .gov)
  -be skeptical of blogs, personal websites, advocacy groups

Question 40

What are some characteristics of peer reviewed (scholarly) journals?

Answer 40

Have a serious appearance.
The words “Journal,” “Transactions,” “Proceedings,” or “Quarterly,” may appear in the title.
Written for professors, students or researchers.
Signed by the authors.
Articles are reviewed by a board of experts or “peer reviewers.”
Follow a format: abstract, literature review, methodology, results, conclusion, possibly footnotes, endnotes and/or bibliography.
May include tables, graphs or illustrations to support research.
Very little advertising.

Question 41

In what order should you read the sections of a primary research article?

Answer 41

1. Begin by reading the introduction, not the abstract
2. Identify the big question
3. Summarize the background in five sentences or less
4. Identify the specific question(s)
5. Identify the approach
6. Read the methods section
7. Read the results section
8. Determine whether the results answer the specific question(s)
9. Read the conclusion/discussion section
10. Go back to the beginning and read the abstract
11. Find out what the other researchers say about the paper