The Senses...Are you hearing this!?

Picture this...You are one week away from the midterm and you have the duty of recalling the last 5 weeks of anatomy structures. What is going through your head right now? Some may be thinking, "Oh, it won't be that bad," others may have the thought, "All those bones and muscles...that is so much to review," and others may just as well think, "This test is going to stomp me!" If there are anatomy students out there that currently have these thoughts, don't worry, it has happened to the best of us. Believe it or not, it happened to me when I took the class. My best advice I can give this week is as follows:

1. Study hard for the Central Nervous System quiz.
2. Once that is completed, use as much time as you can gather to be in the open lab reviewing the first 5 weeks of terms before Friday, February 19th at 1PM.
3. On Friday, February 19th, at 1PM, the midterm exam will be pinned and their will only be one room open for open lab.
4. Just a word of caution concerning this, with the midterm pinned, all you have to study from is at most two cadavers and specimens that are not being used on the test. Remember that the one open lab will be occupied all week by over 800 students.

**In a nut shell, do your best to start your review studies now and don't wait to the last minute to do so. The sooner you start, the better off you will be. Also, you will be much happier and who doesn't like to be happy?!

With that in mind, lets turn our attention to the material for this week, the Peripheral Nervous System. This week is full of so many fun and interesting structures. We have the cranial nerves that are responsible for most of our sensations, the structures of the eye and ear and also the major nerves of the brachial, femoral, gluteal and popliteal regions. It may seem like alot right now but as one begins to study these terms, one will soon find out just how much these structures help us enjoy the little beauties surrounding us. If that is not impressive enough wrap your mind around these interesting details. Did you know that the nose can remember over 50,000 different scents? Did you know that the eye has over 2 million working parts and can process over 36,000 bits of information every hour? Neat, huh!? The senses truly are extraordinary when considered on that kind of scale. Overall, the peripheral nerves, as tiny as they are, allow us to see life around us, taste great food, and hear the most beautiful sounds man and nature can create.

**As you marvel at the wonder of these creations, here are this week's study tips:

The 12 Cranial Nerves: There are a few sayings that you may hear to remember all 12 of these nerves. Here is the story I learned when I took the class:

On Old Olympus Towering Top, A Finely Vested German Viewed A Hawk

Olfactory(I), Optic(II), Oculomotor(III), Trochlear(IV), Trigeminal(V), Abducens(VI), Facial(VII), Vestibulocochlear(VIII), Glossopharyngeal(IX), Vagus(X), Accessory(XI), Hypoglossal(XII)

**Remember that all these names end in "nerve"

Things to note about the Cranial Nerves:

1. Vestibulocochlear nerve is two nerves running together. When studying this nerve, look for the one that is double barreled. It looks like it is coming out of Patrick's ear and this nerve's function is hearing.
2. Trochlear nerve originates at the base of the corpora quadrigemina and wraps around to the front of the pons. This one is a tiny thing so look closely for it!
3. Glossopharyngeal nerve rests above the Vestibulorcochlear nerve. Think of this nerve as being Patrick's glossy hair.
4. Facial nerve acts like Patrick's facial hairs.
5. Abducens nerve rests on Patrick's abdominal muscles.
6. Trigeminal nerve is Patrick's armpit hairs.
7. In Review, this is the order of a few nerves going from the base of the pons up the medulla oblongata: Oculomotor nerve, Abducens nerve, Trigeminal nerve, Facial nerve, Vestibulocochlear nerve, Glossopharyngeal nerve, Vagus nerve and Accessory nerve.

Brachial Plexus

**Look for the "M" nerve in the armpit region. Each leg of the "M" is a different nerve and it goes from lateral to medial according to this saying:

• Mickey Mouse University: Musculocutaneous nerve, Median nerve and Ulnar Nerve. The Radial Nerve dives deep into the "M" because it is too RAD to go to school.
• Musculocutaneous nerve dives deep into the brachial muscles.
• Median nerve is the central leg of the "M".
• Ulnar nerve is on the ulnar side of the arm.

The Eye

The Journey of a Tear:

1. lacrimal gland
2. excretory lacrimal ductules
3. lacrimal punctum: you can see this in your own eye; just look in a mirror, pull down your lower eyelid and look for the hole in the medial portion of the eye.
4. lacrimal canals
5. lacrimal sac
6. nasolacrimal duct: runs through the nasolacrimal canal in the skull.
7. Out the nose: This is why when your cry, your nose gets runny too!

Muscles of the Eye: a few pointers

1. Make sure to orient yourself with they eye specimens and understand what is the superior, inferior, lateral and medial portions of the eye.
2. Lacrimal gland is always lateral
3. Caruncle is always medial
4. On the Superior portion of the eye, the superior oblique is under the superior rectus
5. On the Inferior portion of the eye, the inferior oblique is over the inferior rectus
6. Trochlea: a loop-like piece of tissue that sits on the inside of the orbit and feeds the superior oblique like a pulley system.

Layers of the Eye

• From Superficial to Deep: Sclera, Choroid, Retina

Chambers of the Eye:

1. Anterior Chamber: Cornea to Iris
2. Posterior Chamber: Iris to Lens
3. These two chambers are filled with Aqueous Humor
4. Vitreous Chamber: Entire posterior segment of the eye, located between the posterior side of the lens and the retina
5. This chamber is filled with Vitreous Humor

The Ear

External Ear

• Auricle: Fleshy portion of the ear composed of elastic cartilage.

Middle Ear

• Auditory Ossicles: malleus(hammer), incus(anvil), stapes(saddle stirrup)
• Vestibular window: remember it as the oval window because the semicircular canals on the vestibule are oval shaped.
• Cochlear window: remember it as the round window because the cochlea is round shaped.

Inner Ear

• Vestibule: Innervated by the vestibular nerve; portion of the vestibulocochlear nerve
• Cochlea: Innervated by the cochlear nerve; portion of the vestibulocochlear nerve

Cross Section of the Cochlea

• The two pairs of "Scalas"
• Scala Vestibuli: wear your vest on top
• Scala Tympani: wear your pants on the bottom
• Both the "scalas" are filled with perilymph(Pair-e-lymph)
• Cochlear Duct is in between both "Scalas" and is filled with Endolymph
• Tectorial Membrane: resembles a diving board
• Spiral Organ of Corti: consists of ONLY the basilar membrane and the cochlear hair cells

** Have fun learning the senses and happy studying!!!