Question 1

Which of the following is most likely to increase the sensitivity of the stretch reflex?

Accepted Answer

A) Cutting dorsal root fibers associated with muscle in which stretch reflex is being examined 
B) Increasing activity of medullary reticular nuclei 
C) Bending head forward 
D) Increased activity in fusimotor (gamma motor neuron) system 
A) Cutting dorsal root fibers associated with muscle in which stretch reflex is being examined 
B) Increasing activity of medullary reticular nuclei 
C) Bending head forward 
D) Increased activity in fusimotor (gamma motor neuron) system D

Question 2

Which of the following is true regarding stimulation of type II sensory fibers innervating a muscle spindle?

Accepted Answer

A) Will inhibit muscle contraction 
B) Will activate an inhibitory interneuron in the anterior horn of the spinal cord and lead to inhibition of Golgi tendon response 
C) Will activate a gamma motor neuron connected to the muscle containing the spindle receptor 
D) Will activate an alpha motor neuron connected to the muscle containing the spindle receptor 
A) Will inhibit muscle contraction 
B) Will activate an inhibitory interneuron in the anterior horn of the spinal cord and lead to inhibition of Golgi tendon response 
C) Will activate a gamma motor neuron connected to the muscle containing the spindle receptor 
D) Will activate an alpha motor neuron connected to the muscle containing the spindle receptor D

Question 3

The sensitivity of the stretch reflex can be altered by which of the following?

Accepted Answer

A) Activity in the olivocerebellar tract 
B) Simultaneous stimulation of primary motor cortex and supplemental motor area of cortex 
C) Activity of pontine reticular nuclei 
D) Activity of corticospinal tract 
A) Activity in the olivocerebellar tract 
B) Simultaneous stimulation of primary motor cortex and supplemental motor area of cortex 
C) Activity of pontine reticular nuclei 
D) Activity of corticospinal tract C

Question 4

The stretch reflex initiated by tapping on the patellar tendon causes muscle contraction by which of the following mechanisms?

Accepted Answer

A) Activation of type Ia sensory fibers 
B) Activation of type Ib sensory fibers 
C) Activation of gamma motor neurons 
D) Activation of inhibitory interneurons 
A) Activation of type Ia sensory fibers 
B) Activation of type Ib sensory fibers 
C) Activation of gamma motor neurons 
D) Activation of inhibitory interneurons

Question 5

A 30-year-old man with bare feet steps on a broken bottle with his right foot. His right leg immediately lifts while his left leg extends before he can consciously react to the pain. Use this information to answer the next two questions.
-Which of the following best describes the name of this reflex?

Accepted Answer

A) Walking reflex 
B) Stretch reflex 
C) Patellar tendon reflex 
D) Golgi tendon reflex 
E) Flexor withdrawal reflex 
A) Walking reflex 
B) Stretch reflex 
C) Patellar tendon reflex 
D) Golgi tendon reflex 
E) Flexor withdrawal reflex

Question 6

A Golgi tendon organ is most likely to sense which of the following?

Accepted Answer

A) Fine touch 
B) Length 
C) Pressure 
D) Tension 
E) Vibration 
A) Fine touch 
B) Length 
C) Pressure 
D) Tension 
E) Vibration

Question 7

A 30-year-old man with bare feet steps on a broken bottle with his right foot. His right leg immediately lifts while his left leg extends before he can consciously react to the pain. Use this information to answer the next two questions.
-Which of the following best describes the type of reflex arc and sensory receptor for this reflex? $~~~~~~~\text { Reflex Arc } \quad~~~~~~ \text { Sensory Receptor }$
$\begin{array}{ll}
\hline
\text { A. Disynaptic } & \text { Pacinian corpuscle } \
\text { B. Disynaptic } & \text { Nociceptor } \
\text { C. Monosynaptic } & \text { Pacinian corpuscle } \
\text { D. Monosynaptic } & \text { Golgitendon organ } \
\text { E. Polysynaptic } & \text { Nociceptor } \
\text { F. Polysynaptic } & \text { Muscle spindle }
\end{array}$

Accepted Answer

The answer of A 30-year-old man with bare feet steps...

Question 8

Assuming all sensory, motor, and reflex neuronal pathways are intact, skeletal muscle contraction can be caused by stimulation of which of the following?

Accepted Answer

A) Type 1a sensory nerve endings 
B) Type 1b sensory nerve endings 
C) Neurons in ventromedial hypothalamus 
D) Preganglionic parasympathetic vagal nerves 
A) Type 1a sensory nerve endings 
B) Type 1b sensory nerve endings 
C) Neurons in ventromedial hypothalamus 
D) Preganglionic parasympathetic vagal nerves

Question 9

Under normal conditions, activation of which of the following can lead to muscle contraction?

Accepted Answer

A) Free nerve endings 
B) Type Ia sensory fibers 
C) Nuclear chain fibers 
D) All of the above 
A) Free nerve endings 
B) Type Ia sensory fibers 
C) Nuclear chain fibers 
D) All of the above

Question 10

What is the function of the Golgi tendon organ?

Accepted Answer

A) To sense the length of the muscle tendon in which it is located 
B) To provide the cerebellum with feedback information concerning which motor impulses have arrived at the anterior motor neurons of the spinal cord 
C) To transmit muscle stretch information to higher brain centers 
D) To sense muscle tension and equalize the contractile force exerted by groups of muscle fibers in a muscle 
A) To sense the length of the muscle tendon in which it is located 
B) To provide the cerebellum with feedback information concerning which motor impulses have arrived at the anterior motor neurons of the spinal cord 
C) To transmit muscle stretch information to higher brain centers 
D) To sense muscle tension and equalize the contractile force exerted by groups of muscle fibers in a muscle

Question 11

Assuming all sensory, motor, and reflex pathways are intact, muscle contraction can be caused by stimulation of which of the following types of neurons?

Accepted Answer

A) Alpha motor neurons 
B) Gamma motor neurons 
C) Type 1a sensory endings from a nuclear bag fiber 
D) All of the above 
A) Alpha motor neurons 
B) Gamma motor neurons 
C) Type 1a sensory endings from a nuclear bag fiber 
D) All of the above

Question 12

In a muscle spindle receptor, which fiber is responsible for the dynamic response?

Accepted Answer

A) Extrafusal muscle fiber 
B) Static nuclear bag fiber 
C) Nuclear chain fiber 
D) Dynamic nuclear bag fiber 
A) Extrafusal muscle fiber 
B) Static nuclear bag fiber 
C) Nuclear chain fiber 
D) Dynamic nuclear bag fiber

Question 13

The dynamic response of the muscle spindle receptor can best be described as which of the following?

Accepted Answer

A) An increase in the activity of the nuclear chain fibers as a result of the change in length of the muscle fiber 
B) An increase on activity of the group II sensory afferents in response to the rate of change in length of the muscle fiber 
C) A decrease in the activity of the group 1a sensory afferents in response to a change in length of the muscle fiber 
D) An increase in the activity of the muscle spindle receptor that is proportional to the rate of change in length of the muscle fiber 
A) An increase in the activity of the nuclear chain fibers as a result of the change in length of the muscle fiber 
B) An increase on activity of the group II sensory afferents in response to the rate of change in length of the muscle fiber 
C) A decrease in the activity of the group 1a sensory afferents in response to a change in length of the muscle fiber 
D) An increase in the activity of the muscle spindle receptor that is proportional to the rate of change in length of the muscle fiber

Question 14

Type II sensory afferents from the muscle spindle receptor are attached to which of the following structures?

Accepted Answer

A) Extrafusal muscle fiber 
B) Dynamic nuclear bag fiber 
C) Nuclear chain fiber 
D) Gamma S fiber 
A) Extrafusal muscle fiber 
B) Dynamic nuclear bag fiber 
C) Nuclear chain fiber 
D) Gamma S fiber

Question 15

Activation of a type 1b sensory neuron is most likely to have which of the following effects?

Accepted Answer

A) Contraction of muscle fiber associated with this neuron 
B) An initiation of a complex spike output signal 
C) Central nystagmus 
D) Inhibition of muscle contraction in muscle fiber associated with this neuron 
A) Contraction of muscle fiber associated with this neuron 
B) An initiation of a complex spike output signal 
C) Central nystagmus 
D) Inhibition of muscle contraction in muscle fiber associated with this neuron

Question 16

Type 1a afferents innervate which of the following types of receptors in the muscle spindle apparatus?

Accepted Answer

A) Nuclear chain fibers 
B) Static nuclear bag 
C) Dynamic nuclear bag fibers 
D) All of the above 
A) Nuclear chain fibers 
B) Static nuclear bag 
C) Dynamic nuclear bag fibers 
D) All of the above

Exam 55: Motor Functions of the Spinal Cord; the Cord Reflexes

Which of the following is most likely to increase the sensitivity of the stretch reflex?

Which of the following is true regarding stimulation of type II sensory fibers innervating a muscle spindle?

The sensitivity of the stretch reflex can be altered by which of the following?

The stretch reflex initiated by tapping on the patellar tendon causes muscle contraction by which of the following mechanisms?

A Golgi tendon organ is most likely to sense which of the following?

Assuming all sensory, motor, and reflex neuronal pathways are intact, skeletal muscle contraction can be caused by stimulation of which of the following?

Under normal conditions, activation of which of the following can lead to muscle contraction?

What is the function of the Golgi tendon organ?

Assuming all sensory, motor, and reflex pathways are intact, muscle contraction can be caused by stimulation of which of the following types of neurons?

In a muscle spindle receptor, which fiber is responsible for the dynamic response?

The dynamic response of the muscle spindle receptor can best be described as which of the following?

Type II sensory afferents from the muscle spindle receptor are attached to which of the following structures?

Activation of a type 1b sensory neuron is most likely to have which of the following effects?

Type 1a afferents innervate which of the following types of receptors in the muscle spindle apparatus?

Functional Organization of the Human Body and Control of the Internal Environment

The Cell and Its Functions

Genetic Control of Protein Synthesis, Cell Function, and Cell Reproduction

Transport of Substances Through Cell Membranes

Membrane Potentials and Action Potentials

Contraction of Skeletal Muscle

Excitation of Skeletal Muscle: Neuromuscular Transmission and Excitation-Contraction Coupling

Excitation and Contraction of Smooth Muscle

Cardiac Muscle; the Heart As a Pump and Function of the Heart Valves

Rhythmical Excitation of the Heart

The Normal Electrocardiogram

Electrocardiographic Interpretation of Cardiac Muscle and Coronary Blood Flow Abnormalities: Vectorial Analysis

Cardiac Arrhythmias and Their Electrocardiographic Interpretation

Overview of the Circulation; Biophysics of Pressure, Flow, and Resistance

Vascular Distensibility and Functions of the Arterial and Venous Systems

The Microcirculation and Lymphatic System: Capillary Fluid Exchange, Interstitial Fluid, and Lymph Flow

Local and Humoral Control of Tissue Blood Flow

Nervous Regulation of the Circulation and Rapid Control of Arterial Pressure

Role of the Kidneys in Long-Term Control of Arterial Pressure and in Hypertension: the Integrated System for Arterial Pressure Regulation

Cardiac Output, Venous Return, and Their Regulation

Muscle Blood Flow and Cardiac Output During Exercise; the Coronary Circulation and Ischemic Heart Disease

Cardiac Failure

Heart Valves and Heart Sounds; Valvular and Congenital Heart Defects

Circulatory Shock and Its Treatment

The Body Fluid Compartments: Extracellular and Intracellular Fluids; Edema

Red Blood Cells, Anemia, and Polycythemia

Resistance of the Body to Infection: I Leukocytes, Granulocytes, the Monocyte-Macrophage System, and Inflammation

Resistance of the Body to Infection: Ii Immunity and Allergy

Blood Types; Transfusion; Tissue and Organ Transplantation

Hemostasis and Blood Coagulation

Pulmonary Ventilation

Pulmonary Circulation, Pulmonary Edema, Pleural Fluid

Physical Principles of Gas Exchange; Diffusion of Oxygen and Carbon Dioxide Through the Respiratory Membrane

Transport of Oxygen and Carbon Dioxide in Blood and Tissue Fluids

Regulation of Respiration

Respiratory Insufficiencypathophysiology, Diagnosis, Oxygen Therapy

Aviation, High Altitude, and Space Physiology

Physiology of Deep-Sea Diving and Other Hyperbaric Conditions

Organization of the Nervous System, Basic Functions of Synapses, and Neurotransmitters

Sensory Receptors, Neuronal Circuits for Processing Information

Somatic Sensations: I General Organization, the Tactile and Position Senses

Somatic Sensations: II Pain, Headache, and Thermal Sensations

The Eye: I Optics of Vision

The Eye: II Receptor and Neural Function of the Retina

The Eye: III Central Neurophysiology of Vision

The Sense of Hearing

The Chemical Sensestaste and Smell

Cortical and Brain Stem Control of Motor Function

Contributions of the Cerebellum and Basal Ganglia to Overall Motor Control

Cerebral Cortex, Intellectual Functions of the Brain, Learning, and Memory

Behavioral and Motivational Mechanisms of the Brainthe Limbic System and the Hypothalamus

States of Brain Activitysleep, Brain Waves, Epilepsy, Psychoses, and Dementia

The Autonomic Nervous System and the Adrenal Medulla

Cerebral Blood Flow, Cerebrospinal Fluid, and Brain Metabolism

General Principles of Gastrointestinal Functionmotility, Nervous Control, and Blood Circulation

Propulsion and Mixing of Food in the Alimentary Tract

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