Graphs in Physiology

Question 1

The horizontal axis of a graph is called the ______________, whereas the vertical axis is called the ____________.

Answer 1

x-axis or abscissa, y-axis or ordinate

Question 2

Which graph (A or B) shows the effect of Na⁺ conductance (gNa⁺) on the flux of Na⁺ ions across a cell membrane?

Answer 2

A: since gNa⁺ is on the abscissa, it is the independent variable producing the cause (Na⁺ flux).

Graph A is an example of a cause:effect usage and graph B has the convention reversed.

Question 3

Which graph (A or B) shows how transmembrane potential (Emem in mV) varies with extracellular [K+] in mM. Assume all other factors are equal.

Answer 3

B: The statement implies that [K⁺]_ECF is the independent variable causing a change in the dependent variable (E_MEM), so convention has [K+]_ECF plotted on the abscissa (x-axis).

Graph A would apply to some effect of E_MEM on [K+]_ECF, not what was posed here.

Question 4

This graph below shows the effect of __________________ to determine __________________.

Answer 4

lung ventilation, arterial O2

Question 5

This graph below shows the effect of __________________ to determine __________________.

Answer 5

arterial O2, lung ventilation.

Question 6

The graph below shows two physiological mechanisms: the effect of ___________ on ____________ and the simultaneous effect of _____________ on ___________.

Answer 6

Arterial O2, lung ventilation (and) lung ventilation, arterial O2.

Question 7

This type of graph below is called a ____________ plot and has _________ as the independent variable.

Answer 7

temporal, time

Question 8

An x-y plot shows how two variables change relative to _____________.

Answer 8

each other

Question 9

True or false: In an x-y plot, there is a definite cause-effect relationship between the x and y variables.

Answer 9

True if they represent a physiological mechanism; false if they simply occur simultaneously in time.