EXAM 3 ~ labs p.2

What is the ventricular system component associated with the diencephalon?

3rd ventricle

Why is the spinal cord shorter than the vertebral column in an adult human?

Because the bones of the skeleton, and therefore the vertebral column continue to grow long after the spinal cord has reached its full length.

Where is the subarachnoid space?

Between the arachnoid and pia mater

Which cranial nerve can be tested by shining a light into the patient's eyes to test pupillary constriction?

CN III or oculomotor.

Which cranial nerve or nerves is/are tested by drawing an "H" in the air with your finger, and asking the patient to follow your finger with their eyes?

CN III, IV, and VI

Which cranial nerve can be tested by asking the patient to clench their jaw tight by contracting their masseter muscle?

CN V - trigeminal nerve.

Damage to which nerve causes deafness?

CN VIII - vestibulocochlear

Which ventricle(s) is/are located in the cerebrum?

Lateral ventricles

The cell bodies of sensory neurons are located inside ____________.

The dorsal root ganglion contains the cell bodies of sensory neurons.

Which of the following cranial nerves carries only motor information?

abducens.

Which arteries travel through the interhemispheric (longitudinal) fissure to provide oxygenated blood to the medial portion of the cerebrum?

anterior cerebral arteries

arteries part of the circle of willis

anterior communicating artery, posterior cerebral artery, anterior cerebral artery, and posterior communicating artery.

What is the name of the knob-like projections that reabsorb CSF and return it to the bloodstream?

arachnoid granulations

The middle layer of meninges that has spider-web like projections extending from its inferior side is called the

arachnoid matter.

Where is the 4th ventricle?

between the pons and cerebellum

Which nerve plexus contains nerves that travel to the upper limb?

branchial plexus.

Which ventricular system component is associated with the midbrain?

cerebral aqueduct

Spinal nerves that innervate the upper extremity come from _____________ spinal levels.

cervical. The upper extremity is innervated by nerves from the brachial plexus. These nerves arise mostly from cervical spinal levels. The spinal levels that form the brachial plexus are spinal cord levels C5 - T1. Spinal nerves from the lumbosacral plexus innervate the lower extremity. The lumbosacral plexus is formed from the overlap of the lumbar plexus (levels L1 - L5) and the sacral plexus (L4-S4).

What produces cerebrospinal fluid or CSF?

choroid plexus

All of the pairs below are correctly matched

cranial nerve VI: eye movement. cranial nerve III: oculomotor nerve. optic nerve: sensory. cranial nerve III: pupillary constriction.

where is CSF found

deep to the arachnoid matter, between the arachnoid matter and Pia matter, central canal, and the subarachnoid space.

In the video, Dr. Jaworski mentions that spinal levels C3, C4, C5 innervate an important structure in the ventral body cavity by repeating this phrase "C3, 4, 5 keeps the __________ alive!" What is that structure?

diaphragm. The phrenic nerves are formed by contributions of spinal levels C3, C4 and C5 from the cervical plexus. These important nerves (one on each side of the body) leave the neck region, travel through the mediastinum of the thorax (in between the heart and lungs) and innervate the diaphragm - an important large, flat skeletal muscle that regulates breathing. If this muscle becomes paralyzed because of damage to the phrenic nerves (or because of a cervical spinal cord injury), a patient will need to be on a respirator for breathing.

Sensory information enters the spinal cord on the

dorsal side. Sensory information enters the spinal cord through the dorsal root entry zone on the dorsal side of the spinal cord. Motor information leaves the spinal cord on the ventral side of the spinal cord.

Separation of the periosteal and meningeal layers of the dura mater forms

dural sinuses

What cranial nerve can be tested by asking the patient to squeeze their eyes shut?

facial nerve.

The cervical enlargement

is located in the cervical area, and roots of the nerves that innervate upper extremity structures enter and leave the spinal cord in this region.

The tibial nerve innervates all of the following muscles

Gastrocnemius, Semitendinosus, and Biceps femoris.

How does CSF get into the subarachnoid space?

It leaves the 4th ventricle through holes or apertures to enter the Cisterna magna

Which cranial nerves carry the sensation of taste?

facial, glossopharyngeal, vagus.

Which combination of cranial nerves is responsible for controlling eye movements?

oculomotor, trochlear and abducens

Which nerve is injured when you hit your "funny bone"?

ulner nerve. The ulnar nerve is vulnerable to injury in the spot where it rests against the medial epicondyle in the elbow. Because of this, striking your "funny bone" or the medial side of your elbow results in pain and tingling in the medial side of your hand. If the injury is more severe, you may have trouble making a fist or gripping objects.

Which cranial nerve is also known as "the wanderer" because it travels extensively, innervating many of the visceral organs of the thorax and abdomen?

vagus nerve. The vagus nerve, or CN X, is sometimes called the wanderer, because it is the only nerve that extends beyond the head and neck region, and in fact, extends through the thorax and into the abdomen. The vagus nerve has many functions, but also provides parasympathetic innervation to the heart, lung, liver and small intestine. The vagus nerve is responsible for slowing the heart rate.

Which statement is TRUE about the hypoglossal nerve?

If it is damaged, the patient's tongue will deviate toward the side of the lesion.

What is the name of the large artery that brings oxygenated blood to the anterior part of the brain?

Internal carotid artery

Deoxygenated venous blood leaves the brain through which large blood vessel?

Internal jugular vein

Sciatica is a condition that usually results from compression of nerve roots that contribute to formation of the sciatic nerve. In this condition, a patient may experience pain radiating

down the posterior side of the lower limb. The sciatic nerve has two divisions which provide innervation to the posterior thigh, posterior, anterior and lateral leg, and the foot. Injury to the sciatic nerve can have significant impact due to its extensive course through the lower limb.

Bell's Palsy is a condition in which a patient has paralysis or weakness of the muscles on one side of their face. Typical symptoms include drooping of the lower eyelid, one side of the mouth is turned down, inability to close the eye on one side, possible drooling or excessive tear production and loss of taste. In most cases, Bell's Palsy is thought be caused by a virus that affects one of the cranial nerves, and not by a stroke or TIA (transient ischemic attack). Which cranial nerve is affected in Bell's Palsy?

facial nerve or CN VII. Damage to the facial nerve causes Bell's Palsy (usually due to inflammation). Weakness or paralysis of the muscles of facial expression cause one side of the face to droop and may affect taste, saliva & tear production. This condition comes on suddenly, often overnight, and usually gets better by itself within a few weeks.

What is the name of the dural septum that sits in the longitudinal fissure between the 2 hemispheres of the brain?

falx cerebri

The sciatic nerve is formed from which nerve plexus?

lumbosacral plexus. The sciatic nerve is the largest nerve in the body and is formed by contributions of axons from spinal cord levels L4 - S3 (lumbosacral plexus).

nerve that is negatively affected during carpal tunnel syndrome

median nerve. The median nerve and the tendons of the flexor digitorum muscles travel through the carpal tunnel, a small tunnel that is formed by the position of the carpal bones in the wrist. Overuse and inflammation of the tendons cause the tendon sheaths that surround them to swell, compressing the median nerve. This causes tingling and numbness of the areas served by the median nerve, and weakness of the thumb muscles.

Which artery brings oxygenated blood to most of the lateral surface of the cerebrum?

middle cerebral artery

The femoral nerve innervates

muscles in the anterior compartment of the thigh.

The Peripheral Nervous System or PNS is made up of

nerves and ganglia.

Which cranial nerve can be assessed by asking the patient to smell a cotton swab that contains vanilla extract?

CN I - olfactory nerve.

Dr. Jaworski explained in her video that one of the cranial nerves can't be seen on the inferior surface of the brain or brainstem. However, she did explain that the axons from the cranial nerve do synapse on a structure that we can see on the inferior surface of the brain. What is the cranial nerve, and what is the structure that we can see on the inferior surface of the brain?

CN I - olfactory nerve; olfactory bulb.

Which cranial nerve collects visual images from the eye?

CN II - optic nerve

Which cranial nerve can slow the heart rate?

CN X - vagus

Which cranial nerve arises from upper spinal cord segments and then travels upward through the foramen magnum before traveling to innervate two major (and large) muscles of the head and neck?

CN XI - spinal accessory

Which cranial nerve will you be testing if you ask the patient to raise their shoulders, or to turn their head and resist you trying to push it back?

CN XI - spinal accessory nerve.

CSF is produced continuously throughout the day. What prevents too much accumulation of CSF in the brain?

CSF gets reabsorbed by arachnoid granulations which return CSF to a dural sinus called the superior sagittal sinus.

What is the name of the arterial anastomosis at the base of the brain?

Circle of Willis

Dr. Davies described that 3 cranial nerves have a role in swallowing. What are these nerves?

IX, X and XI. cranial nerves IX (glossopharyngeal), X (vagus) and XI (spinal accessory) all have a role in swallowing. The glossopharyngeal nerve and vagus nerves innervate muscles of the pharynx and larynx, and anatomists say that CN XI (spinal accessory) innervates pharyngeal muscles through fibers that actually travel with cranial nerve X (vagus).

You enter a patient's room and find them on the floor unconscious. You immediately shine a light into their eyes and tell your colleague, "Their pupils are fixed and dilated." Which of the following statements is most likely to be true?

This isn't good. CN III (oculomotor) has been affected in some way.

structures involved in removing deoxygenated blood from the brain

When 2 layers of dura come together, they can form special dura folds called dural septa. These dural septa separate different parts of the brain and have specific names, depending where they are located. The dural septum that extends into the interhemispheric fissure and separates the right and left cerebral hemispheres is called the falx cerebri. There is another dural septum that forms a tent-like structure over the cerebellum - it is called the tentorium cerebelli, and provides support for the posterior portion of the cerebrum. Venous blood flows in the spaces between the layers of dura, and these spaces are called dural sinuses or venous sinuses. The sinuses collect blood from the veins of the skull and brain and all drain inferiorly until they eventually drain into the internal jugular vein. The dural sinus that is located at the superior surface of the brain in the interhemispheric fissure is called the superior sagittal sinus, and the sinus in the inferior edge is called the inferior sagittal sinus.

What three nerves can be tested by asking the patient to repeat the phrase pa, ka, ta?

facial, glossopharyngeal, hypoglossal. these three cranial nerves need to be intact to make these three sounds. The facial nerve controls the muscles of facial expression, so CN VII must be intact in order for the patient to make the "P" sound when they say "pa". The glossopharyngeal nerve must be intact in order for the patient to make the "K" sound when repeating "ka". The hypoglossal nerve controls movements of the tongue, so CN XII must be intact in order to make the "T" sound of "ta".

The brain is protected by 3 layers of meninges but the spinal cord is only protected by dura mater.

false. Both the brain and spinal cord are protected by 3 layers of meninges that are continuous between the brain and spinal cord.

Which ventricle is continuous with the central canal of the spinal cord?

fourth ventricle.

five spinal cord levels

from top to bottom: cervical C1-C8 Thoracic T1-T12 Lumbar L1-L5 Sacral S1-S5 Coccygeal Co1

choroid plexuses

hang from the roof of each ventricle form CSF. These plexuses are clusters of blood capillaries covered by pia mater and then by a layer of ependymal cells lining the ventricles. Fluid filters from the blood capillaries and the composition of the fluid is modified by special pumps in the ependymal cells. The composition of the CSF is carefully controlled by the ependymal cells, which is important because CSF mixes with the extracellular fluid bathing the neurons in the brain. The cilia on the apical surface of the ependymal cells help keep the CSF in constant motion as it flows through the ventricular system.

What is the name of the condition that results if the flow of CSF is blocked or obstructed in some way?

hydrocephalus

Which nerve can be tested by asking the patient to stick out their tongue?

hypoglossal - CN XII

List the structures that CSF flows through (in order) as it travels through the ventricular system.

lateral ventricles, interventricular foramina, 3rd ventricle, cerebral aqueduct, 4th ventricle

What is one way that cranial nerve V, or trigeminal nerve can be tested?

lightly brushing the face on the forehead, cheeks and jawline and ask the patient whether each side feels that same. The trigeminal nerve or cranial nerve V has three sensory divisions that collect sensory innervation from the three regions of the face. The trigeminal nerve also innervates the muscles of mastication (somatic motor).

Droopy upper eyelids, double vision and dilated pupils can result from injury to the

oculomotor nerve. In addition to its other functions of controlling extraocular eye muscles (eye movements) and autonomic functions of the eye (pupil constriction and lens focusing), the oculomotor nerve, or CN III provides somatic motor innervation to the levator palpebrae muscle which is responsible for lifting (levator) the upper eyelid (palpebrae). Don't confuse this function with CN VII (facial nerve) which is responsible for controlling the muscles of facial expression. CN VII controls the orbicularis oculi which is responsible for squeezing the eyes shut, but does not control lifting the eyelid. You don't need to know the names of these muscles for ANPS19, but you should understand the clinical significance of injuries to these nerves and how a patient would present if they had an injury to these nerves.

A patient is suffering from the inability to distinguish various types of odors. This patient may have damage to which of the following?

olfactory nerve (I).

Damage to which nerve causes blindness?

optic nerve

Which cranial nerve can be assessed by testing whether the patient's visual fields are intact?

optic nerve - CN II

This purely sensory cranial nerve carries signals associated with vision.

optic.

Name the most important nerve from the cervical plexus and identify the structure it innervates.

phrenic nerve: diaphragm. The cervical plexus is formed by a network of nerve fibers from spinal nerves C1 through C5. Some of these small nerves innervate muscles of the neck, but the single most important nerve (one on each side of the body) from this plexus is the phrenic nerve which is formed by nerve fibers from C3, C4 and C5. The phrenic nerve runs inferiorly through the thorax, passes by the heart and supplies both motor and sensory fibers to the diaphragm, which is the chief skeletal muscle involved in breathing.

Which artery brings oxygenated blood to the posterior part of the cerebrum?

posterior cerebral artery

Which nerve plexus gives rise to the sciatic nerve?

sacral plexus.

The dorsal root ganglion contains the cell bodies of neurons carrying which type of information?

sensory. The dorsal root ganglion contains cell bodies of sensory neurons which are bringing sensory information (touch, temperature, pain, joint position) from the periphery to the CNS. There are no synapses in the dorsal root ganglion because the sensory neurons are of the pseudounipolar type of neuron. These neurons have one axon which divides into a peripheral process (the part from the periphery) and central process (extends to the spinal cord). The action potentials travel through the axon from the periphery to the spinal cord and do not need to stop at the dorsal root ganglion.

choroid plexus

special structure responsible for the production of CSF.

All of the following statements are TRUE about spinal nerves and cranial nerves

spinal nerves can form nerve plexuses which means that a single skeletal muscle can be innervated by nerve fibers from multiple spinal cord levels, spinal nerves are mixed nerves with both sensory and motor nerve fibers, and cranial nerves extend from the brain to structures in the head and neck.

Which space contains the CSF?

subarachnoid space

What is the name of the dural sinus at the superior edge of the falx cerebri?

superior sagittal sinus

The basilar artery supplies oxygenated blood to

the brainstem and cerebellum

As a cook chops red onions he begins to tear up due to activation of the lacrimal gland. Which of the following nerves provided the stimulus?

the facial nerve (VII).

What is the name of the very large nerve that can be found on the surface on the pontine protuberance? It has 3 sensory divisions and 1 motor division.

the trigeminal nerve.

How do spinal nerves leave the bony vertebral column to get to the periphery?

they travel through intervertebral foramina. The dorsal and ventral rootlets of each spinal cord level join together to form the spinal nerves. Each spinal nerve travels through the intervertebral foramen that was formed between two adjacent vertebrae. For instance, the spinal nerve from cervical level 5 (C5) travels through the intervertebral foramen (hole) formed by the C4 and C5 vertebrae. Make sure you understand the difference between the intervertebral foramen, which is the lateral hole that spinal nerves travel through to exit the vertebral column, and the vertebral foramen, which is the large hole in the center of each vertebral bone, which forms the vertebral column when the vertebrae are stacked on top of each other.

The two divisions of the sciatic nerve are the

tibial and common fibular nerves. The sciatic nerve is actually made up of two nerves that travel within one connective tissue sheath (epineurium), until they separate, usually just proximal to the popliteal fossa (posterior side of knee). These two nerves are the tibial nerve and the common fibular nerve.

What forms the blood-brain-barrier (BBB)?

tight junctions between epithelial cells of capillaries and foot processes of astrocytes.

nerves that innervate muscles of the forearm

ulnar, median, and radial nerves.

Which cranial nerve innervates most of the visceral organs?

vagus. The vagus nerve has many targets in the thoracic and abdominal cavities and innervates many of the visceral organs.

Which structure contains the axons of motor neurons leaving the spinal cord?

ventral root. The cell bodies of motor neurons are located in the ventral horn gray matter of the spinal cord. The axons of these motor neurons leave the spinal cord through the ventral root and travel to the periphery to innervate skeletal muscles.

What is the name of the arteries that travel through the foramen magnum to provide oxygenated blood to the posterior portions of the brain?

vertebral arteries

Which of the listed nerves are purely sensory?

vestibulocochlear or CN VIII.

Problems in balance may follow trauma to which nerve?

vestibulocochlear.

Which nerve is being tested by asking the patient when they can hear the rubbing sounds?

vestibulocochlear. Cranial nerve VIII is the vestibulococlear nerve. This nerve is purely sensory and has two divisions. The vestibular division conveys the sense of equilibrium and balance, and the cochlear division is responsible for hearing (audition).