The topic: grammar, spelling and nerves.

Wait, did I read that correctly?

Yes. Not only did I expect my students to be on top of their anatomy and physiology when they handed in written reports, I even went so far as to correct their spelling. Particularly after we’d finished studying nerves.

What? Why?

Because there is a difference between how one should use the words affect and effect.

Yes, I know it sounds picky. No, I’m not perfect at grammar and spelling, not even close. But someone who has just finished studying nerves in an college level anatomy and physiology course should know the difference between afferent nerves and efferent nerves.

I’m lost.

Okay. Normally, I’d use the standard example of holding a bare hand over an open flame. But, for fun, let’s take this down a more romantic pathway…

Nate pulled Katherine out of the sudden rainstorm to stand beneath the building’s overhang. His strong arm wrapped about her waist as he tugged her tightly against his hard length. His other hand cupped the base of her skull, pulling her face close enough so that the heat of his breath warmed her lips. The scent of wet wool and something that was uniquely Nate met her nose. The rough pads of his thumbs brushed over the angle of her jaw. Every nerve tingled in anticipation of his kiss.

We can break the nervous system down into two categories: afferent nerves and efferent nerves.

Oh, sorry, did I interrupt your fantasy? *snaps fingers* You’re in class. Focus.


Afferent nerves, aka sensory nerves, conduct impulses TOWARD the central nervous system (the brain and spinal cord = CNS).

Let’s focus on Katherine. In this case, our hero’s presence is sensed by our heroine’s afferent nerves. She can feel his arm, his breath, his thumbs. She can smell his clothes, the soap he used.

Nate is affecting Katherine’s senses. She’s not – for the moment – doing anything. She’s standing there and letting outside influences act upon her. She is being acted upon, feelings are stirring.

Out -> In.

Affect (v): 1) to act on; produce an effect or change in 2) to impress the mind or move the feelings of.

Katherine slid her hands upward over Nate’s firm chest, her fingers curving over his broad shoulders. What was he waiting for? She tipped her face upward and closed her eyes. Still nothing. He was far too much the gentleman. She pushed onto her toes and dragged him downward, humming with deep contentment when at last their lips met.

Ahem. *taps toe*

Efferent nerves, aka motor nerves, carry impulses AWAY from the central nervous system causing muscles to contract, to do something.

In this case, Katherine has effected a change. Her hands, fingers, face, toes, arms – all of them, courtesy of a number of moving muscles, contributed to physical movement that ended with Nate kissing her. Her actions produced an effect on Nate – which had the desired effect: a kiss.

In -> Out.

Effect (v): to produce as an effect; bring about; accomplish; make happen (n) a change that occurred.

Generally speaking, the way to think about this is to consider the person, place or thing that is being influenced. Is it being acted upon? Affected. As Katherine was when Nate drew close. Or is it causing an action to occur? Effected. As Katherine did when she caused Nate to kiss her.

And there you have it, the odd, rambling and strange manner a former biology professor uses to remember the difference between affect and effect. Perhaps it will also help you the next time you need to choose between the two words?

About Anne

Though USA TODAY bestselling author Anne Renwick holds a Ph.D. in biology and greatly enjoyed tormenting the overburdened undergraduates who were her students, fiction has always been her first love. Today, she writes steampunk romance, placing a new kind of biotech in the hands of mad scientists, proper young ladies and determined villains.

Anne brings an unusual perspective to steampunk. A number of years spent locked inside the bowels of a biological research facility left her permanently altered. In her steampunk world, the Victorian fascination with all things anatomical led to a number of alarming biotechnological advances. Ones that the enemies of Britain would dearly love to possess.

To chat with Anne, stop by on Facebook or join the Department of Cryptobiology Facebook group. You can also join her newsletter list to have cover reveals, sneak peaks, sales and giveaways delivered straight to your inbox.

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