- Excitability.

-Def:- is the ability of cells to respond to stimuli.

-Excitability of cells and tissues is a basic function of life,as it is necessary for the functioning of nerves, muscles, and hormones,etc...

-The basis for the excitability of cells is their ion distribution, and the distribution of ions and molecules is determined by transport mechanisms associated with their plasma membrane structure.
-This structure permits and regulates various forms of ionic and molecular transport.

-Stimuli which induce Excitability are classified into two types:-
1-electrical. (galvanic ,faradric)
2-chemical.( ions , chemical transmitters, gases,……etc)

-you must know that:-
Excitable cells are those that can be stimulated to create a tiny electric current which in turn is transformed into physiological function and excitable cells are of three types:-

• Muscle cells.
• Nerve cells (neurons).
• Glandular cells.

- Anatomy of the External nose.

- The external nose extends the nasal cavities onto the front of the face and positions the nares so that they point downwards.

- The anterior parts of the nasal cavities are held open by a  skeletal framework (i.e external nose ).

- The external nose is pyramidal in shape , has anterior border called "dorsum" and two lateral sides.
- It´s root lies at the naso-facial suture.
- It´s apex called the tip of the nose.
- The septum below the tip of the nose called "columella".
- The opening of the nose to air is called "nostrils" or "anterior nares" which are openings through which air enters nasal cavities...

- The external nose is composed of two parts:

1- Upper bony part:-
which is composed of :

• Nsal bones which is articulate together in the middle line .
• Nasal process of frontal bone.
• Nasal process of maxillry bone.

2- lower cartilagenous part:-
which is composed of :

• upper lateral cartilage.
• Major alar cartilage(lower lateral cartilage).
• Minor alar cartilage at ala nasi.

N.B: Major alar cartilage is composed of two crura lateral and medial.
The two medial crura form "columella".

*References:-
-Netter anatomy atlas.
-Richard l.darke,wayne vogl& Adam mitchell:Gray´s anatomy for students.
-Mohammed Fareed:Illustrated Otolaryngology.
-Hassan Allam:Manual of Otorhinolaryngology.
-Mansoura E.N.T department:Essentials of Otorhinolaryngology.

-Ten ways to reduce risk of cancer.

1- Balanced diet ( which supply the body with sufficient food stuffs,satisfy body requirement,free of toxins or infection,selected in proper portion 50-60% cHO,15-20% proteins,20-30% fat).

2-choose diet rich in fibers.

3-Increase vegetables and fruits for more than 2 servings /day.

4-Control weight,avoid obesity.

5-Excercise regularly.

6-limit highly salted food.

7-limit smoky and  pickled food.

8-Decrease fat intake.

9-Stop alcohol.

10-Stop smoking with its different forms (cigarettes,Bidi,Cigar,Goza ,Hook-ah,Hubble-bubble,Tobacco chewing,Snuff,pipe).

Dr Ibrahim samaha

-Three in human ear.

There are...

- 3 parts of the human ear:-

1. External ear.
2. Middle ear.
3. Inner ear.

- 3 parts of the External ear:-

1. auricle (pinna).
2. external auditory meatus.
3. Tympanic membrane.

- 3 layers in tympanic membrane:-

1. Outter skin layer.
2. middle fibrous layer.
3. inner mucosal layer.

- 3 cranial nerves innervate the tympanic membrane:-

1. C.N. V (trigeminal).
2. C.N. IX(glossopharyngeal).
3. C.N. X (Vagus).

 -3 Parts of middle ear:-

1. Tympanic cavity.
2. Eustachian tube.
3. Mastoid air cells.

- 3 parts of the tympanic cavity:-

1. epi-tympanum.
2. meso-tympanum.
3. hypo-tympanum.

- 3 middle ear bones (auditory ossicles):-

1. malleus.
2. incus.
3. stapes.

- 3 parts of the malleus:-

1. Head.
2. lateral process.
3. handle.

- 3 parts of labyrinth:-

1. Bony cochlea.
2. 3 semicircular canals.
3. Vestibule.

- 3 semicircular canals :

1. Posterior.
2. lateral.
3. superior.

- 3 compartments of cavity of bony cochlea :-

1. scala vestibuli: Upper compartment.
2. scala media (cochlear duct):middle compartment.
3. scala tympani: lower compartment.

- 3 membranes in cochlear duct:-

1. vestibular.
2. Tectorial.
3. Basilar .

- 3 labyrnthine sensory end organs:-

1. Of cochlea..called organ of corti.
2. of s c c....called crista.
3. of utricle and saccule..called macula.

Enjoy it,,,,,
Dr Ibrahim...

-Dangerous area of the face.

Dangerous area of the face

- It is the area () the root of  the nose and 2 angles of the mouth.
- The veins in this region are connected to cavernous sinus so any infection in this area may lead to cavernous sinus thrombosis.

- Venous draingae of Dangerous area:-

• Antearior and  post etmoidal veins drain to opthalmic vein.
• sphenopalatine & greater palatine veins drain to pterygoid veins.
• Angular vein,lateral nasal and superior labial veins drain to facial vein...

- All of the above veins drain finally to cavernous sinus.

So, Donnot put your finger in your nose..:)

See you,
Dr Ibrahim...