Ch. 13 The Peripheral Nervous System and Reflex Activity

Marieb - Human Anatomy & Physiology 11th Edition

Marieb, Hoehn11th EditionHuman Anatomy & PhysiologyISBN: 9780136874034Not the one you use?Change textbook

Marieb, Hoehn 11th Edition

Ch. 13 The Peripheral Nervous System and Reflex Activity

Problem 10

Chapter 13, Problem 10

A reflex that causes reciprocal activation of the antagonist muscle is the
(a) crossed-extensor
(b) flexor
(c) tendon
(d) muscle stretch.

Name: Human Anatomy & Physiology
Author: Marieb, Hoehn
ISBN: 9780136874034

Verified step by step guidance

Step 1: Understand the concept of reciprocal activation in muscle reflexes. Reciprocal activation refers to the process where the contraction of one muscle (the agonist) is accompanied by the relaxation of its opposing muscle (the antagonist).

Step 2: Review the types of reflexes listed: crossed-extensor, flexor, tendon, and muscle stretch reflexes, and identify which one involves reciprocal activation.

Step 3: Recall that the muscle stretch reflex involves the muscle spindle detecting stretch and causing the agonist muscle to contract while simultaneously inhibiting the antagonist muscle through reciprocal inhibition.

Step 4: Recognize that the flexor reflex primarily causes withdrawal of a limb and does not necessarily involve reciprocal activation of the antagonist muscle in the same way.

Step 5: Conclude that the reflex responsible for reciprocal activation of the antagonist muscle is the muscle stretch reflex.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Reciprocal Innervation

Reciprocal innervation is a neural mechanism where activation of one muscle (agonist) causes inhibition of its antagonist muscle, allowing smooth and coordinated movement. This process prevents muscles that oppose each other from contracting simultaneously.

Muscle Stretch Reflex

The muscle stretch reflex is an automatic response where a muscle contracts in response to being stretched. It involves sensory receptors called muscle spindles that detect stretch and trigger motor neurons to activate the same muscle while inhibiting the antagonist.

Antagonist Muscle Activation in Reflexes

Certain reflexes, like the muscle stretch reflex, involve reciprocal activation where the agonist muscle contracts and the antagonist muscle is inhibited. Understanding which reflex causes this reciprocal activation helps identify the correct reflex type.

Recommended video:

3:01

Tendon Reflex

Related Practice

Textbook Question

Match the names of the cranial nerves in column B to the appropriate description in column A.

Column A

_______ (1) Causes pupillary constriction

_______ (2) The major sensory nerve of the face

_______ (3) Serves the sternocleido-mastoid and trapezius muscles

_______ (4) Purely sensory (two nerves)

_______ (5) Serves the tongue muscles

_______ (6) Allows you to chew your food

_______ (7) Impaired in Bell's palsy

_______ (8) Helps regulate heart activity

_______ (9) Helps you hear and maintain your balance

_______ (10) Contain parasympathetic motor fibers (four nerves)

Column B

a. Abducens

b. Accessory

c. Facial

d. Glossopharyngeal

e. Hypoglossal

f. Oculomotor

g. Olfactory

h. Optic

i. Trigeminal

j. Trochlear

k. Vagus

l. Vestibulocochlear

views

Textbook Question

The connective tissue sheath that surrounds a fascicle of nerve fibers is the

a. Epineurium

b. Endoneurium

c. Perineurium

d. Epimysium