Scientific Measurement & Physiology Labs – Exam Review

35 question-and-answer flashcards that review key concepts from Lab 1 through Lab 13, covering measurement, graphing, osmolarity, sensory physiology, cardiovascular dynamics, and more.

What is the definition of “data” in scientific measurement?

Factual information or values gathered from experiments that serve as a basis for reasoning, discussion, or calculation.

In experimental design, what is meant by a “variable”?

A measurable factor that can be changed, adapted, or varied during an experiment.

Why is including a unit essential whenever you report a measurement?

Because physical variables require specific standards; without a unit, the measurement is meaningless.

How are metric-system units related to one another, and why is that helpful?

They are related by powers of ten, which makes converting between units as simple as moving the decimal point.

Why is calculating the mean valuable when evaluating physiological data?

It summarizes a data set and allows comparison of an individual’s value to the population mean to spot abnormalities.

Which type of graph is most appropriate for comparing average values of a variable between different groups?

A bar graph.

On an X–Y graph, which axis displays the independent variable?

The X-axis (horizontal axis).

How does a line graph differ from a scatterplot?

A line graph connects continuous data from the same individual, whereas a scatterplot shows separate points to compare different individuals and often uses a best-fit line.

What is a “best-fit line” used for on a scatterplot?

To illustrate the overall trend of the data points and allow prediction of one variable from the other without needing to touch every point.

When converting metric units, which direction do you move the decimal when going from a larger unit to a smaller unit?

Move the decimal to the right, giving the number a larger numerical value.

What does molarity (M) express?

The number of moles of solute per liter of solution.

Differentiate between solvent and solute.

The solvent is the liquid that dissolves substances; the solute is the substance being dissolved.

What is osmolarity, and how does ionization affect it?

Total solute particle concentration (osmoles per liter); if a solute dissociates into ions, osmolarity equals moles multiplied by the number of ions produced.

During osmosis, toward which area does water move?

Toward the area with higher solute concentration (lower water concentration).

How does temperature influence the rate of osmosis?

Higher temperature increases the rate; lower temperature decreases it.

Define a hypertonic solution relative to the cell interior.

A solution with higher solute concentration and lower water concentration than the cytoplasm.

What is osmotic pressure?

The pressure that must be applied to resist water movement across a membrane during osmosis; higher solute concentration equals higher osmotic pressure.

What two stimuli typically trigger the human diving reflex?

Cold water contacting the face and voluntary breath-holding (apnea).

Name the three hallmark physiological responses of the diving reflex.

Bradycardia, apnea, and increased peripheral vasoconstriction.

Which cranial nerve’s ophthalmic branch mediates the facial cooling component of the diving reflex?

The trigeminal nerve (cranial nerve V).

What does a two-point discrimination test reveal about a body region?

The density of tactile receptors: smaller receptive fields and more receptors give finer discrimination.

Why can pain from a heart attack be felt in the left arm (referred pain)?

Sensory pathways from the heart and left arm converge onto the same spinal neuron, causing the brain to misinterpret the pain’s location.

Interpret the meaning of 20/20 visual acuity.

At 20 feet you can read what a normal eye reads at 20 feet—considered standard (normal) vision.

What visual defect does astigmatism testing detect?

Irregular curvature of the cornea or lens that prevents uniform focusing, causing certain lines to appear blurred.

What is the anatomical basis of the eye’s blind spot?

The optic disc, where ganglion cell axons exit as the optic nerve; it lacks photoreceptors so produces no image.

What is the purpose of the pupillary light reflex, and which autonomic branches control constriction and dilation?

To regulate retinal light exposure; parasympathetic input constricts pupils, sympathetic input dilates them.

Which valves close to create the first heart sound ("lub")?

The atrioventricular (mitral and tricuspid) valves.

During manual blood-pressure measurement, what does the first audible Korotkoff sound represent?

The systolic blood pressure—the pressure when blood first begins to spurt through the compressed artery.

How do arterial baroreceptors respond to an acute rise in blood pressure?

Increased stretch increases their firing, prompting reflex parasympathetic activation that lowers heart rate and blood pressure.

What criteria define orthostatic hypotension?

A drop of ≥20 mmHg in systolic pressure or a rise of ≥20 beats/min in heart rate upon standing.

Why does heart rate decrease when a standing person squats?

Squatting boosts venous return and stroke volume, raising pressure sensed by baroreceptors, which reflexively slow the heart.

State Poiseuille’s Law formula for blood flow.

Blood flow = (π ΔP r⁴) / (8 η λ), where ΔP is pressure difference, r radius, η viscosity, and λ length.

What is the effect of increasing blood viscosity on flow through a vessel?

Higher viscosity raises resistance and therefore decreases blood flow.

If a vessel’s radius doubles, how does its resistance change?

Resistance drops to 1⁄16 of its original value, so flow increases sixteen-fold.

Explain the relationship between vessel radius and frictional resistance.

Larger radius means less blood touches the wall, reducing friction and resistance; smaller radius increases wall contact, boosting resistance.

King Henry Died by drinking Chocolate Milk. Unlike Normal People.

Mega: 10^6

King: Kilo 10³

Henry: Hecto

Died: Deka

by: Meter, Liter, Gram 10^0

drinking: Deci 10^-1

Chocolate: Centi 10^-2

Milk: Milli 10^-3

Unlike: Micro 10^-6

Normal: Nano 10^-9

People: Pico 10^-12

Proportion

a specific type of ratio in which two ratios are expressed as equal to solve for unknown quantities. Used to find unknown quantities/numerical values

Ratio

mathematical expression that relates two quantities by division and is used to compare two quantities

• Quantities must have the same units