Lesson: Chapter 6 — Human body processes

Reflexes and the autonomic nervous system 2 of 3

Reflex actions

Reflexes are grouped by where they are controlled.

Spinal reflexes

Controlled by the spinal cord.

Pulling a hand away from a hot object or a thorn.

The knee jerk.

Cranial reflexes

Controlled by the brain.

Blinking when something comes near the eye.

The pupil narrowing in bright light; sneezing, coughing, salivating.

Try it — the knee jerk

Sit with one leg crossed loosely over the other. A partner taps just below the kneecap with the side of the hand. The lower leg kicks forward without your deciding to.