GI absorption Chapter (2):- the oral cavity part(1)

§Av been overthinkin lately

Its been hard on me

Even after sleep i can't rest

I need to think but

Don't want to

I fear my mind to go in a blank

To stop working or functionnn

Ooooo

I don't wanna think§

-by me hahaha

Man yesterday was a weird day, suddenly i couldnt accept more info, maybe i have overdid it and need a rest hahaha!!

*disclaimer:- many new concepts will be present here and i only put a pic to convey there meaning, also most of the time i referred to the human body as our kid so be awar!!

Here is chapter 2 LETS STARTTTTT

Chapter(2):- the oral cavity part(1)

“Food, food? I see foooooood!” The optic nerve shouted excited,

and at the same time our kid’s olecranon nerve stated, “ what a lovely smell!!?”

These two are cranial nerve 1 (Olfactory) and cranial nerve 2 (optic) that controul our smell and sight respectively

We humans simply have two major division of nerves, center nervous system which compose of the brain and the spinal cord,

And the peripheral nervous system which one of its types is the cranial nerves

12 cranial nerves that control many of our senses. CN 1 is the olfactory nerve, while CN 2 is the optic nerve.

*knock~knock* Meanwhile, in his cranial cavity resides the tired brain.

Hearing the knocks on his door, he shouted, “who in the world dares to miss with me while i need food???”

“FOOD”, the two cranial nerves shouted but the brain simply responded with a laim response, “huh? He this uni kid is surely seeing food in the streets, sigh go tell the minor salivary glands to secret some slayiva”

~anatomy and histology~

The minor salivary glands are small glands distributed in the mucous membrane of the mouth and the tongue.

Do you when I told you that the digestive tract is made up from muscles and its covering epithelial?

Well it is quite more complicated than that hahaha!

Our digestive tract is composed of four layers:-

1- mucosa or the mucus membrane:-

  i- an epithelial lining

   ii- a loose connective tissue called lamina propria

  iii- some smooth muscles

   iv- and some minor glands that secrete mucus

2- submucosa:- a denser connective tissue that has the main supply of nerves, blood vessels and lymph nodes

3- muscularis:- which is composed of two layers of muscles with the internal layer in a longitudinal configuration and the outer one to be in a circular configuration، except in the ureter which is the opposite

4- serosa:- the lining epithelial or mesothelium that lines all cavities

Now our uni kid’s moth can be only described as a watery-mouth but…

~neurology~

Suddenly the two salivary nuclei lights, the superior and inferior salivatory nuclei, light in a bright way inside the brain’s cranial cavity

“Fo-fo food has really appeared!”, with a trampling voice he was shocked

“Finallyyyyyy, i want every type of nerves to start acting as fast as they can” the brain is really excited this time, after all only taste buds found on our tongue’s papillae can induce these two signals

In an angry tone, the brain continued issuing his orders, “ parasympathetic nerve be ready,”

“Stimulate the facial nerve and the glossopharyngeal nerve at once” those are the seventh cranial nerve and the ninth cranial nerve respectively

“The war has begun”, and this was his last order for now, meanwhile the seventh nerve went into his destination the sublingual and the submandibular glands.

In the oral cavity there are three main salivary glands, the sublingual, submandibular and the parotid gland.

The seventh nerve is responsible to stimulate the sublingual and the submandibular glands, as for the ninth nerve is responsible for the parotid gland.

When the ninth nerve, named the glossopharyngeal nerve, reached the parotid gland it stated “a message from the controller, a message from the brain”

Stopping for a while while preparing the message, (by a while i literally mean less than a second!), “at once start the secretion of saliva, food has been served, here is your ACh”

Then throwing a large bunch of small particles through exocytosis, then simply leaving

Holding the bunch the particles through its protein receptors, the parotid gland smirked slightly and thought to itself, ‘looks like those two will start secreting their secretions too, hohoho lets see who is the best secrtor hahaha’

“Now lets wise use our given Acetylcholi…”, but before it continues its speech someone intriptid her, “OHIOOOO”

“Yo, long time no see parotid, i have no time, so here is your norepinephrine”, without saying any word she, the parotid gland, took the other signal in fear from its new visitor.

What she was given are two neurotransmitters that need to be used wisely or else she may die.

The first was acetylcholine (ACh) the main neurotransmitter of the parasympathetic system, this autonomic nervous system controls our basic homeostasis responses such as thirst and hunger.

But the other neurotransmitter was norepinephrine, the main signal used by the sympathetic nervous system, which controls our fight or flight response.

A very strong response that can initiate the burn of the whole body to produce as much energy as possible, that is why the parotid gland was afraid from him.

~physiology~

Returning to our parotid gland she ordered it’s cells, “at once! Right now stimulate the production of muscarinic receptors by the newly acquired ACh”

She continued shouting, “we need the highest homeostatic amount of 1,4,5-triphosphate (ip3) right now!!”

One of her cell minions asked, “but why Ip3 madam?”

She sweetly answered, “ we need them for the IP3R receptors”

The cell did not understand and shook it’s head will saying, “huh?”

‘What a silly cell I have!’, The parotid gland wanted to laugh enterinaly from this cell’s cuteness, but answered frimley, “ will you see, what do we have in our acinar cells?”

“Some enzymes such as a-amylase and lingual lipase, but most important water and electrolytes such as Na, Cl & K”

“Ok, and what do we have in our endoplasmic reticulum?”

The cell not understanding the reason for these question answerd, “ a large storage of Ca++”

But suddenly a light bulb appeared on top of the cell’s head, “ and the IP3R receptors that need IP3 to be activated have the function of secreting our cytoplasmic calcium, right?

“Yes you are right, but what will happen next?” The parotid asked

“An electrochemical gradient that will secrets other electrolytes outside the cell” with amazement the cell answerd.

“You are right, we the parotid gland secrets a serous secretion, but the sub duo secrets a mixture of our section and a mucus secretion” she added , then looked into the cell in a challenging manner, “ do you know what’s the difference?

“Yes I know, mucus is filled with the disgusting mucins glycoproteins, and cuz of its glycoprotein continent it traps water so it acts as a lubricant” the cell answered in a rapid manner.

“Very good, very good…” she started prising the cell but suddenly her composition changed, “WHY ARE YOU LAZING AROUND?, go work”

“Ye-yes madam” and the cell run into it’s working place

“Sigh, Really the myoepithelial cells ask too much”, the myoepithelial cells are the ones that control the secretion, because they have actin and myosin filaments they contract exactly like muscles.

~histology~

There are many parts in a gland that effects its secrtion:-

1- the ancius which has many shapes mostly alveolar and tubular

2- the duct system

Now lets see what happens intracellularly in the ancius of the parotid gland

Hehehe still need some editing but am toooo tired to do that! Seeya guys next timeee