Case study 2 - The Nervous System

Where in the neuron are neurotransmitters manufactured? a. Rough endoplasmic reticulum (Nissl bodies) b. Nucleus c. Axon d. Dendrite

a. Rough endoplasmic reticulum (Nissl bodies)

Which of the following correctly name sites that are routinely used to test myotatic reflexes?

- Patellar ligament - Achilles (calcaneal) tendon - Triceps brachii - Finger flexors - Biceps brachii - Patellar ligament - Brachioradialis

Match each term to the most appropriate corresponding answer 1. The area of skin on the body supplied by one spinal nerve 2. All of the muscles innervated by one spinal nerve 3. well defined, localised sensory loss 4. Widespread but poorly-defined region of sensory loss 5. The site of injury or disease in the nervous system A. likely spinal nerve lesion B. dermatome C. myotome D. likely cutaneous branch lesion E. lesion

1. B 2. C 3. D 4. A 5. E

Arrange the following structures in the correct order where 1 is medial (closest to the spinal cord) and 4 is lateral. - Dorsal root - Dorsal root ganglion - Spinal nerve - Dorsal rootlet

1. dorsal rootlet 2. dorsal root 3. dorsal ganglion 4. spinal nerve

In what situations would a clinician perform a myotatic reflex?

A clinician would perform myotatic reflexes if they wished to evaluate that the components of the myotatic reflex (i.e peripheral nerves and spinal cord) are intact and not damaged. This is a routine part of a neurological exam.

What is a myotatic reflex?

A reflex is an involuntary, stereotyped response to a specific stimulus. In the case of a myotatic reflex the specific stimulus is a stretch of the muscle spindle and the stereotyped response is a reflex contraction of the same skeletal muscle that has been stimulated.

What does an absent myotatic reflex indicate?

It indicates that there is dysfunction of one or more component(s) of the reflex system. This could be due to a problem with the: 1. Afferent neuron 2. Spinal cord (the integrating centre) 3. Efferent neuron 4. The skeletal muscle itself.

What is the muscle spindle? Do all three types of muscle contain muscle spindles?

The muscle spindle is a specialised non-contractile sensory organ. It is exclusively found in skeletal muscle. The muscle spindle detects static length of a muscle and dynamic length changes (stretch). It is innervated by efferent gamma (γ) motor neurons and also afferent sensory neurons.

Clinical testing of myotatic reflexes is performed using a reflex hammer. Which anatomical area would you strike with your hammer to elicit a reflex?

The tendon of the muscle

In which region of the spine do spinal nerves exit the vertebral canal superior to their named vertebrae? a. Cervical b. Thoracic c. Lumbar d. Sacral and coccygeal

a. Cervical

Which of the following structures can be found on neurons, muscles and glands? a. Post-synpatic membrane b. Pre-synaptic membrane c. Axon terminal d. Dendrites

a. Post-synpatic membrane

Which area of a neuron receives information that leads to the propagation of an action potential? a. Axon b. Dendrite c. Myelin sheath d. Axon terminal

b. Dendrite

Sensory information enters the spinal cord through the __________ horn and motor information exits the spinal cord through the ____________ horn. a. Anterior, ventral b. Dorsal, ventral c. Ventral, dorsal d. Dorsal, median

b. Dorsal, ventral

When you look at the central nervous system, why does white matter appear white? a. It contains myelin produced by Schwann cells b. It contains myelin produced by oligodendrocytes c. It does not contain any myelin d. It contains nerves and ganglia

b. It contains myelin produced by oligodendrocytes

The connective tissue sheath that surrounds a fascicle of axons is the... a. Endoneurium b. Perineurium c. Epinerium d. Schwann cell

b. Perineurium

The axons of a ventral ramus can either be segmented or integrated with axons from other ventral rami to form a plexus. The ventral rami of which of the following regions remain segmented and do not form a plexus? a. Cervical b. Thoracic c. Lumbosacral

b. Thoracic

The presence of what structure allows us to identify the ventral side of the spinal cord? a. Posterior median sulcus b. Posterolateral sulcus c. Anterior median fissure d. Central canal

c. Anterior median fissure

Which of the following is true about myelination? a. The myelin sheath insulates the axon and slows down the transmission of action potentials b. Only multipolar neurons have a myelin sheath c. Both the myelin sheath and the nodes of Ranvier speed up the transmission of action potentials d. A neuron cell body produces its own myelin shea

c. Both the myelin sheath and the nodes of Ranvier speed up the transmission of action potentials

What fluid is found in the subarachnoid space and central canal? a. Blood b. Plasma c. Cerebrospinal fluid d. Lymph

c. Cerebrospinal fluid

Which type of neuron has its cell bodies in the spinal cord and stimulates muscle? a. Bipolar b. Pseudo-unipolar c. Multipolar

c. Multipolar

There are a number of reasons why epidural injections are safer to perform caudal to the level of L1/2. Which one of the following is not one of these reasons? a. There is an absence of spinal cord below this level b. There is less risk of severe neural injury c. There is no epidural space caudal to L1/2 d. The vertebral canal primarily contains nerve roots caudal to this level

c. There is no epidural space caudal to L1/2

Which of the following are functions of the nervous system? i) Establishing and maintaining mental activity ii) Receiving sensory input iii) Controlling muscles and glands iv) Integrating information a. ii and iii b. i, ii and iv c. iv only d. All of the above

d. All of the above

Which of the following statements is true? a. The ventral root of a spinal nerve contains only the axons of motor neurons b. The dorsal root of a spinal nerve contains only the axons of sensory neurons c. The dorsal primary ramus and ventral primary ramus contain axons of both sensory and motor neurons d. All of the above e. None of the above

d. All of the above

Why is there a need for an increased spinal cord volume at the cervical and lumbosacral enlargements? a. Nerves to and from the upper and lower limb synapse with the spinal cord in these locations b. The areas house many cell bodies and tracts c. A large surface area is needed to integrate the large volume of sensory and motor information coming in and out of the area d. All of the above

d. All of the above

Which of the following structures would you not find in grey matter in the central nervous system? a. Cell bodies b. Dendrites c. Synpases d. Myelinated axons

d. Myelinated axons

A collection of cell bodies in the central nervous system is called a ________ but a collection of cell bodies in the peripheral nervous system is called a ____________. a. Nerve, tract b. Tract, nerve c. Ganglion, nucleus d. Nucleus, ganglion

d. Nucleus, ganglion

Which of the following sensations may lead to stimulation of a pseudo-unipolar neuron? a. Pain b. Pressure c. Heat d. Cold e. All of the above f. None of the above

e. All of the above