Tuesday, December 31, 2013

Parotid tumors mnemonic

I had trouble remembering that Warthin's tumor is "Papillary cystadenoma lymphomatosum" and this happened.
Yes, feel the "Warth" (or maybe I'm just weird!)


Wrath of the Pa-cyst-ans? Warthin's tumor? Papillary-cystadenoma-lymphomatosum? YES!

Saturday, December 28, 2013

Bio-statistics mnemonics, tips & tricks

Hey everyone!

I thought of writing the whole blog at once as I have a lot of mnemonics and tricks but I barely get time and it has been pending for a long time now so I thought of publishing it, hoping I'll keep updating this post as and when possible :)

Relative risk and Attributable risk mnemonic

Which cell secretes what? Gastric mucosa histology mnemonics

"pH" for Parietal cells secrete H+ ions.
Parietal cells are also known as oxyntic cells.

"PC" for Pepsin is secreted by Chief cells.
(Chief cells are also known as peptic cells or zymogen cells.)
Alternate mnemonic: I think of master chef making food rich in proteins, peptides being degraded by pepsin and that's how I remember the association that Chief cells secrete Pepsin.

G for G cells & G for Gastrin. (Hah! That was easy!)

S for S cells & S for Secretin! (Medicine is easy!)

Thursday, December 26, 2013

Cardiac Output and Venous Return curve mnemonic

Let's have some fun! =D

A diagram to brush up your memory..
(And to remind you it's all simple & easy and that you've got this!!)

Cardiac Output and Venous Return curve simplified
I used to freak out when I first starting seeing this graph and related multiple choice questions in question banks. It's only in a matter of time that I realized these problems need only three variables to be figured out to choose the right answer!

Wednesday, December 25, 2013

Case scenarios: When you don't give patients 100% O2 and why

Clinical scenario #1: Chronic lung disease patient.

The ventilatory drive of patients with chronic lung disease is primary due to their hypoxemia, rather than CO2 levels. This is because pCO2 receptors are adaptive. Chronically elevated pCO2 makes central receptors unresponsive in COPD patients. Administration of a high O2 mixture to relieve the hypoxemia is contraindicated because this removes the hypoxic drive, leading to severe hypoventilation.

Clinical scenario #2: Drug overdose where central receptors are blocked.

Monday, December 23, 2013

Healthy food: Salads


Hey everyone!

I thought of sharing something that inspired me.. It's about nutrition (Not my regular study post!)

In this age where cardiovascular problems and cancer have been on the rise like never before, it has become essential for us to eat healthy. We need to cut down on bad cholesterol and encourage fiber, nutrient rich, natural, unprocessed food.

Recently, there was a salad making competition held in my mom's school. Children of the second grade helped their mummy's make salads in the school.

Friday, December 20, 2013

Difference between Iris repositor and IOL dialer

Iris repositor has a straight or bent "blade" with blunt edges.

IOL dialer has a bent "tip".

This diagram should help you -

Sunday, December 15, 2013

Human developmental index and physical quality of life index mnemonic

For Human Developmental Index remember, "Humans LIKe development"
So it takes into consideration: Life expectancy, Income & Knowledge.

Physical Quality of Life Index, "LIL physical quality"
It takes into consideration: Life expectancy, Infant mortality, Literacy.

For remembering the I in both mnemonics, I think that development is linked to money (income).
LIL should remind you of the little one, that is, the kid & hence infant mortality!

Friday, December 13, 2013

Mnemonics on nutrition

Hey guys!
These are some mnemonics I made on nutrition which is a part of my Preventive & Social Medicine (also known as Community Medicine).
We'll keep updating this section.
Please, please, please feel free to add your mnemonics as well ^__^

Deficiency of vitamin B1:
Thiamine deficiency causes Ber1 Ber1 (B1).

Deficiency of vitamin B2:
"A2 B2 C2"
A2 - 2 ATPs (FAD and FMN are derived from riboFlavin)
B2 - Vitamin B2
C2 - Cheilosis, Corneal vascularization
Let’s call it ri-two-bo-flavin!

Saturday, December 7, 2013

Innervation of the tongue, palate, pharynx & larynx with mnemonic

Hey everyone!
We are learning innervation of some muscles today! Yaay!

Glossal means pertaining to or near the tongue.. That's your starting point.

All muscles ending in "glossus" are supplied by hypoglossus
..Except palatoglossus.

Why? Because palate!

All musles of the palate are supplied by the vagus
..Except tensor veli palatani.

Why? Because it's a tensor!
All muscles in the head beginning with "tensor" are supplied by V3.

Pharynx and larynx is easy too.. All you need is a mnemonic!

Tuesday, December 3, 2013

Competitive and non competitive inhibitors simplified


Let me present to you the most understandable, simplified, awesome analogy for explaining competitive and non competitive inhibitors =D

Sunday, November 24, 2013

Aortic arch derivatives mnemonic images

I made these diagrams guessing they'll be helpful ^__^

Aortic arch derivatives
The greater part of the first and second artery disappear. In adult life first arch artery is represented by the maxillary artery and the second arch persists for some part of fetal life as the stapedial artery.
The mnemonic people use for that is, "First is max" & "Second is Stapedial" =)

Saturday, November 23, 2013

Competitive vs Non-Competitive Inhibitors mnemonic

Competitive vs Non-Competitive Inhibitors mnemonic graph
Kompetitive Inhibition: Km Increases; no change in Vmax.

Non-kompetitive inhibition: No Km change, but Vmax decreases.

Usually, on the Lineweaver-Burk Plot, Vmax will represent the Efficacy of a drug on the Y axis & Km will represent the Potency on the X axis.

Mnemonic: "Very efficient & competent"

Of course, that Lineweaver-Burk guy was very efficient & competent! 

The place where I live, there is a tailor's shop named competitive scissors. That's how I remember that competitive inhibitors cross the vectors at the Y axis in Lineweaver-Burk Plot.

Another way to remember this is, competitive inhibitors cross each other competitively, whereas noncompetitive inhibitors do not.

Another mnemonic to remember the shift to left or right in the simple graph is explained in the Oxygen hemoglobin dissociation curve mnemonic.

Hope it helps ^_^

-IkaN

Wanna reblog? Here's the link to the tumblr post!

Credits for "Competitive scissors" mnemonic goes to KhalifaUSMLE

Friday, November 22, 2013

Difference between ribose and deoxyribose sugar menmonic

Difference between ribose and deoxyribose sugar menmonic
In ribose, carbon atom 2 (C2) carries one hydroxyl group.

In deoxyribose, carbon atom 2 (C2) carries a hydrogen atom instead of a hydroxyl group.

Mnemonic:
"Conversion of RNA 2 DNA involves C2"
"Conversion of RNA to DNA involves the second carbon atom"


Wednesday, November 20, 2013

Nucleoside vs Nucleotide

Nucleoside vs Nucleotide
Nucleoside and Nucleotide mnemonic:
nucleoSide has Sugar and baSe.
nucleoTide has phosphaTe.

"Captain Obvious reporting to duty!"

Amino acids necessary for purine synthesis mnemonic

Amino acids necessary for purine synthesis menmonic
Amino acids necessary for purine synthesis menmonic:
"GAG"
Glycine. Aspartate. Glutamine.

The image helps me remember "Purines" & "Gag" together.

"PURr GAGa"

Tuesday, November 19, 2013

Purine and pyrimidine nucleotides mnemonic

Mnemonic for purine nucleotides:
"Pure as gold"
"PURe as AG"
Purine nucleotides are Adenine and Guanine.

"Goooold"












Mnemonic for pyrimidine nucleotides:
"Cut the pie"
"CUT the PY"
Pyrimidine nucleotides are Cytosine, Uracil and Thymine.

"3.14159265..."










How to remember that it is pyrimidine - pyrimidine dimers and not purine - purine dimers that are formed on exposure to UV light: Pyrimidine is the bigger word. People who have big hearts fall in love with each other.

"It's bigger on the inside."

-IkaN

Mnemonic for base pairing of nucleotides

DNA base pairs menemonic

Mnemonic for base pairing of nucleotides:
"GCAT"
G ≡ C, A = T.
Guanine forms three hydrogen bonds with cytosine.
Adenine forms two hydrogen bonds thymine.

"Gee.. CAT!"

Amino acids with electrically charged side chains mnemonic



Mnemonic for positively charged basic amino acids:
"He is liar"
"Heis LyAr"
Histidine. Lysine. Arginine.

"He is basically a liar, he is positively a liar, LyAr Heis."

Say that to yourself a few times and you've got em memorized! =P






Mnemonic for negatively charged amino acids:
"GA"

Glutamate. Aspartate.

Glutamic acid. Aspartic acid. Acidic amino acids.

"GAGAGAGAGA"








Updated on 22/11/2013:
Question asked on tumblr:
Basicity: the willingness to donate electrons
Wait, why would they be positive again? Aaaaahhhh

Answer:
Hey don’t get confused between your “basic” concepts! *pun intended*

I was talking about being positive in the physiological pKa.

All amino acids can act as either an acid or a base because they have a carboxyl group than can lose protons and an amino group than can gain protons/donate electrons.

Amino acids that are said to be basic have an extra moiety which will accept electrons (Their side chains contain nitrogen and resemble ammonia, which is a base at neutral pH).

They will have iso electric points at a pH higher than physiological pH and will be positively charged at physiological pH (You need a more alkaline environment to obtain an overall neutral charge because the amino group can hold onto another proton).

In other words, their pKa’s are high enough that they tend to bind protons, gaining a positive charge in the process.


Similarly, amino acids that are said to be acidic have an extra carboxyl group. They will have iso electric points at a pH lower than physiological pH and be negatively charged at physiological pH (You need a more acidic environment to obtain an overall neutral charge because the carboxyl groups can more easily lose a proton).

Sunday, November 17, 2013

Multiple Endocrine Neoplasia mnemonic

Hey everyone!

I modified the mnemonic I had for the MEN syndromes to make them work for me =)
Here it goes -

Mnemonic for MEN I: "I pee."
For MEN I, remember the P's.
Pituitary, Parathyroid, Pancreas.

One sounds like, "Won", reminding us that MEN I is also known as Wermer's syndrome.

Mnemonic for MEN IIA: "I am meant to sit in an AC room."
For MEN IIA, remember the C's.
Calcitonin, Calcium, Catecholamines.

I think of "2 ASS" to memorize MEN 2A is also known as Sipple Syndrome.

Mnemonic for MEN IIB:
"Every man wants to bePharaoh with a Medium Car on Mars with the New Romans."
Pheocytochroma, Medullary carcinoma, Marfan's syndrome, Neuromas.

I made an illustration for this too xD

MEN IIB illustration mnemonic

Friday, November 15, 2013

Tropia vs Phoria

What is Strabismus?
A condition in which the eyes are not properly aligned with each other.

What is tropia?
A misalignment of the two eyes when a patient is looking with binocular vision and the two eyes are looking at the same object.

What is phoria?
A misalignment of the two eyes that only appears when binocular viewing is broken and the two eyes are no longer looking at the same object.

Thursday, November 14, 2013

Progression of visual field defects in Glaucoma mnemonic

I had to memorize this for med school exams T_T

What is Glaucoma?
A group of disorders characterized by progressive optic neuropathy resulting in characteristic appearance of optic disc & a specific pattern of irreversible visual field defects that are associated frequently but invariably with raised intraocular pressure (IOP).
(Simply put, optic nerve fibres are damaged in glaucoma making the optic disc look funny & causes vision loss. It may or may not be associated with raised pressure in the eye.)

Loss of nerve fibres causes visual field defects & optic disc changes in glaucoma.

This blog post covers visual field defects =)

Mnemonic: IC BB Wings & SAD Steps

Progression of visual field defects in Glaucoma mnemonic

Friday, November 1, 2013

Intrinsic & extrinsic incubation period

What is incubation period?
The time interval between invasion by an infectious agent and the appearance of the first sign or symptom of the disease in question. (It is also known as intrinsic incubation period if spoken in reference to a vector borne disease.)

What is extrinsic incubation period?
In reference to vector borne diseases, it is the period of time necessary for the development of disease agent in the arthropod host or invertebrate which transmits infection.

For example: Malaria.
The extrinsic incubation period is the period of time required for the development of the parasite from the gametocyte to sporozoite stage in the body of the mosquito.
It is about 10-28 days depending on the vector species, temperature & humidity.

Monday, October 28, 2013

Hashimoto's & Graves' disease mnemonic

In Hashimoto’s disease, there are antibodies against thyroid peroxidase (TPO) and/or thyroglobulin.
It is the most common cause of primary hypothyroidism.

In Graves’ disease, there are antibodies against thyrotropin receptor (TSH receptor) also known as Thyroid Stimulating Immunoglobulins (TSI).
It is the most common cause of primary hyperthyroidism.

Thursday, October 10, 2013

Miosis & Mydriasis mnemonic

Hi everyone!
Eye see you reading this post.. EYE see you, get it? ;)
We are learning about the eye today, isn't that spectacular? =P

We should stop using ophthalmology puns, they are way too cornea! :D

Let's get started, seeriously!

What is miosis?
Constriction of the pupil.

What is mydriasis?
Dilation of the pupil.

Mnemonic:
MyDriasis has a D, D for dilates the pupil.

OR
Mydriasis is a bigger word, so it stands for big pupil (dilated pupil).
Miosis is a smaller word, and therefore is a constricted pupil. 

Nerve supply:
Parasympathetic axons innervate the iris sphincter muscle, producing miosis.
Sympathetic nervous system supplies the iris dilator, composed of radially arranged muscle fibers, producing mydriasis.

How do I remember this? @__@

I am really scared of ghosts, they stimulate my sympathetic nervous system (fight, flight or fright response)
Ghosts show up at night, when there is low light.
Pupils dilate in low light, when my sympathetic nervous system kicks in.
Sympathetic nervous system dilates the pupil!


Sympathetic nervous system dilates the eye (Mydriasis) mnemonic

That's a silly association I use to help me remember.
Hope it helps! ^__^

That's all!


Ghost be like, "I feel you creeping, I can see it from my shadow"

-IkaN


Sunday, October 6, 2013

Emoticon game on Pharmacology

Hey everyone!
We recently got 500 followers on tumblr & I couldn't think of a more fun way to celebrate it!! =D

Emoticon game
I won't be posting the answers online but you can email me on medicowesome@gmail.com for the answers and I'll get back to you as soon as I can!

That's all!

-IkaN

Tuesday, September 24, 2013

Monday, September 23, 2013

Wire vectis


Lid clamp or entropion clamp


Lens spatula


de Wecker's scissors


Corneal scissors or section enlarging scissors


Chalazion clamp




PSM flashcards

Hey everyone!
I've also been making PSM flashcards for myself.
For all those who don't know, PSM is Preventive and Social Medicine.

Cat paw retractor

*meow*

Saturday, September 21, 2013

Tuesday, September 17, 2013

Difference between Pemphigus vulgaris & Bullous pemphigoid mnemonic

Hello everyone!

Pemphigus vulgaris & Bullous pemphigoid are autoimmune diseases of the skin.

Here's a strange association I've made in my head to help me remember most of the points about Pemphigus vulgaris.. And then, I remember that the other one is the other one =D

Kelman-McPherson forceps


Cystotome (Capsulotome)



Introducing instruments

*talking to myself*

I have to learn about surgical instruments for my practical exams.
It's BORING.
Especially, when I know that I might never even get the chance to use them :\

Let's draw them!!
And write funny and cool descriptions about them!!

Friday, September 13, 2013

How to remember the difference between Wernicke's area and Broca's area

Hola!
We'll be learning about the Wernicke's area and Broca's areas of the cerebral cortex!

Let's get started <3

What is Broca's area?
It is the motor speech area.
Motor? Yeah, it helps in movements required to produce speech.

What is Wernicke's area?
It is the sensory speech area.
Sensory? Yes, it helps you understand speech.
It also helps in usage of correct words to express our thoughts.

Wednesday, September 11, 2013

Tuesday, September 10, 2013

Difference between chronic atrophic gastritis type A and type B

What is chronic atrophic gastritis?
It is a process of chronic inflammation of the gastric mucosa.

What are the causes of chronic atrophic gastritis?
It can be caused by persistent infection with Helicobacter pylori, or can be autoimmune in origin.

Thursday, September 5, 2013

Memorizing how to draw the nasal septum

Hey everyone!

Here's a mnemonic kinda video for how to draw the nasal septum --> http://www.youtube.com/watch?v=vY9dwSDNTLQ

I've always had problems remembering the names of various bones and cartilages so I made a silly mnemonic for myself.

Tuesday, August 20, 2013

Darrow-Yannet Diagrams simplified

What are Darrow Yannet diagrams?
They are graphs that tell you the osmolarity and volume changes of body fluids.

X axis represents volume.
Y axis represents solute concentration.

Total body water = 2/3 ICF (Intracellular fluid) + 1/3 ECF  (Extracellular fluid)

Remember:
All volume disturbances originate in the ECF compartment.
Changes in ICF are in response to changes in ECF.

How to make the graph in your head -
Step 1. Figure out what happens to the osmolarity and volume in the ECF compartment (ECF is the smaller compartment)
Step 2. Think how is ICF affected?

Let's review some examples to make sure we understand the concept!

Thursday, August 15, 2013

How to remember lipoprotein disorders

Hello everyone!

Click here to read about Lipoproteins and apoproteins if you need a quick revision before we get started :)

In this blog post, I'll be talking about lipoprotein disorders, how to remember them and some facts that you need to know about the disorders.

Friday, August 9, 2013

What is the difference between prerenal failure & acute tubular necrosis?


What is prerenal failure?
Prerenal acute renal failure (ARF) occurs when a sudden reduction in blood flow to the kidney (renal hypoperfusion) causes a loss of kidney function.
In prerenal acute renal failure, there is nothing wrong with the kidney itself.

What is acute tubular necrosis?
Acute tubular necrosis is a kidney disorder involving damage to the tubule cells of the kidneys, which can lead to acute kidney failure.

What is the difference between prerenal failure & acute tubular necrosis?

Thursday, August 8, 2013

Arteriovenous fistula - What happens to cardiac output and total peripheral resistance and why?

What is an AV fistula?
An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein.

When an arteriovenous fistula is formed involving a major artery like the abdominal aorta, it can lead to a large decrease in peripheral resistance.

Why?

Wednesday, August 7, 2013

Medicowesome Flashcards 2 download

Hey everyone! <3

Here is the link for the second set of flashcards -
https://docs.google.com/file/d/0B47QBCwY_mUMYmZVbjdlMTlTU1k/edit?usp=sharing


Friday, August 2, 2013

Difference between iron deficiency anemia and anemia of chronic disease

Hi everyone!
Sometimes simply reading doesn't help you get the difference..
So I made these notes to help you have a visual idea of the terms used while describing these diseases.

Tuesday, July 30, 2013

Medicowesome Flashcards 1 download

Hey everyone!
The first set of flashcards are ready for download B)

I sorted them out in different folders in case you wish to study them separately ^_^
Personally, I like mixing them all together and recollecting random facts as they show up.. Gets tougher =D

Wednesday, July 24, 2013

Medicowesome flashcards

Hello!

I've been making flash cards for myself.
I've made them as images so that I can put it in my cellphone or tab and revise them while I'm traveling ^_^

Wednesday, July 3, 2013

Wednesday, June 19, 2013

Tuesday, June 18, 2013

Friday, June 14, 2013

Emoticon game on Microbiology

Hi everyone!

We will be doing something different and fun today ^___^
We are playing the emoticon game.. Difference is that it's on Microbiology!

Tuesday, June 11, 2013

Sunday, May 12, 2013

Oxygen - hemoglobin dissociation curve mnemonic

Hi everyone!
What is oxygen - haemoglobin dissociation curve or oxygen binding curve?
The oxygen - haemoglobin dissociation curve plots the proportion of haemoglobin in its saturated form on the vertical axis (fractional saturation of hemoglobin) against the prevailing oxygen tension on the horizontal axis.

What does it tell?
It tells you the affinity of hemoglobin for oxygen.

How does it do that?
It's simple!
If the curve shifts towards the right, hemoglobin has decreased affinity for oxygen.
If the curve shifts towards the left, hemoglobin has increased affinity for oxygen.

How do I remember the shift in curves?
Remember: Left shifted curve doesn't want to leave oxygen.

Friday, May 3, 2013

Obstructive and restrictive lung diseases

Happy friday everyone!
We’ll learn about obstructive and restrictive lung diseases today.
This is just a short summary for a quick review :)


Obstructive lung diseases - Characterized by airway obstruction.
You have an obstruction in air flow resulting in air trapping in the lungs.
Increased compliance: Due to the loss of alveolar and elastic tissue.
You have a problem getting air out of your lungs.
Mnemonic: Obstructive Out

They breathe like “poof poooooof”
In and oooooout
They take infinity to get it all out =P
So, FEV1 / FVC is decreased.

TLC and RV increased - Flow volume loop shifts towards left.

Examples: Any pathology that decreases the ability to develop a positive intrapleural pressure.
(Airways close prematurely at high lung volumes!)
Chronic bronchitis
Asthma
Bronchiectasis
Emphysema
COPD

Restrictive lung diseases - Characterized by restriction of lung expansion.
You have a problem getting air into your lungs.
Reduced compliance: Lungs become fibrotic, lose their distensibility and become stiffer.
Mnemonic: Restrictive Reduced compliance

They breathe like “poof pof”
In and out
They get everything out in one second =P
So, FEV1 / FVC is increased.

TLC and RV decreased - Flow volume loop shifts towards the right.

Examples: Any pathology that decreases the ability to develop a negative intrapleural pressure.
Pulmonary fibrosis
Asbestosis
Sarcoidosis
Pneumoconioses
Kyphoscoliosis
ARDS
Polio
Obesity

That's all!

I know you must've found the "poof" sounds pretty weird because that isn't the way you breathe
But they are a funny and they help me remember so I put it up anyway ^___^"
Just like "lup dubb" are official sounds for heart beats.. Which sounds would you assign to inspiration and expiration?

-IkaN

Updated: Diagram on 28th Nov, 2013.

Sunday, April 28, 2013

What are the factors affecting diastolic blood pressure?

Hi everyone!

What is diastolic blood pressure?
It is the pressure that is exerted on the walls of the various arteries around the body in between heart beats when the heart is relaxed.
It is the minimum pressure in the entire cardiac cycle.
So it basically represents amount of blood in arterial system during diastole.

Tuesday, April 23, 2013

Lateral medullary syndrome and lateral pontine syndrome mnemonic

*Super super excited to share this mnemonic with you* ^__^
 But let's get to the basics first!

What is lateral medullary syndrome?
Neurological symptoms due to injury to lateral part of the medulla.
Also called Wallenberg's syndrome.

When does it happen?
When the posterior inferior cerebellar artery is occluded.

What is lateral pontine syndrome?
Neurological symptoms due to injury to lateral part of the pons.

When does it happen?
When the anterior inferior cerebellar artery is occluded.

Saturday, April 20, 2013

Wednesday, April 17, 2013

Free water clearance

Hi everyone!
This is my attempt of explaining everything I know about free water clearance.. Hope you understand :)

What is free water clearance?
Free water clearance (CH2O) is the volume of blood plasma that is cleared of solute-free water per unit time.

What does it mean? @_@
Water follows salt everywhere it goes.
[Think of salt and water as a lovey dovey couple, in a very codependent relationship of course, water being the lead role xP ]

Tuesday, April 16, 2013

Virus mnemonic

Do you know viruses have various shapes?
The simple viruses are either icosahedral or helical.

Cool and important fact:
Icosahedral viruses can either be simply a naked caspid virus or it can be an enveloped caspid virus.
But if a virus is helical, it HAS to be enveloped and surrounded by a nice lipid bilayer (mostly derived from the host cell membrane)

How I remember that helical viruses are always enveloped is:
Think of our DNA!
We have a helical structure.. So the helical viruses can not survive without our cell membranes.
Helical virus forms can not be naked.

I know it's stupid but it makes life easy for me < 3

If you want to stuff your hippocampus with some other facts:

Sunday, April 14, 2013

Nervous system origins mnemonic

Hello everyone :)
Let's get to CNS and PNS origins =D

Neural crest derivatives:
Neural creSt cells have S
Schwann cells have S
Sensory neurons have S
How I remember that neural crest cells give rise to post ganglionic autonomic neurons is that I remember adrenal medulla is derived from neural crest cells which is as good as a post ganglionic neuron!

Note: The cells that give rise to the adrenal medulla are called chromaffin cells.

Mesoderm gives rise to Microglia which are Macrophages of the CNS

Saturday, April 13, 2013

Inactivated sodium channels and Lidocaine (Lignocaine)

Why is lidocaine preferred in patients with arrhythmias following myocardial infarction?

Hypoxic tissue is depolarized.
Na+ - K+ ATPase doesn't work.
Na+ has accumulated in the cell and no one pumps it out.
All the sodium channels are in the inactivated state.

These inactivated channels slow the conduction of electrical activity in ischemic tissue.
This is how arrhythmia arises.
It causes disparity in the way action potentials are propagated in the heart  muscle cells.
The normal fibres wanting to go fast and the hypoxic tissues slowly firing in between :|

That's why you use class Ib antiarrhythmic, lidocaine, in patients with arrhythmias following myocardial infarction.
They block inactivated sodium channels.

Blocking inactivated sodium channels doesn't change any flux of sodium into the cells.
But if you are keeping it inactive, you are preventing it's return back to the resting state.
So you are keeping those cells in hypoxic tissue refractory, keeping them from going back to resting and preventing them in firing new action potentials on their own.

Lidocaine also decreases action potential duration by blocking slow sodium window channels.
In any other healthy cell, this would be proarrhythmic.
But in hypoxic tissue over here, which is already slow in conduction, you'd help it recover faster and help it go back with the healthy tissue for electrical speed.
Or simply by decreasing APD, you'll have more time in disatole for filling.
Either way, you are improving the cardiac output of the ischemic heart :)

Since digoxin is also going to depolarize the heart by blocking sodium channels, lidocaine is also used in digitalis toxicity.

Cool fact:
Lidocaine is also a local anesthetic.
However, preparations for cardiac use contain no preservatives.
Local anaesthetic preparartions should not be used for cardiac purposes.
It is used i.v. due to high first pass metabolism.

Another cool fact:
Mexiletine and Tocainide are lidocaine like drugs and are available in oral formulations.

That's all for today!
 Have a happy healthy Saturday <3
-IkaN

Cardiac fast fibers and slow fibers - Why does a less negative membrane potential convert a normally fast fiber into a slow fiber?

Greetings everyone! :)

What are fast fibers?
Fast fibers have functioning fast channels.
Fast fibers include ventricular fibers, atrial fibers and Purkinje fibers.

What are fast channels?
They are sodium channels that quickly open and close on depolarization.
  
What are slow fibers?
SA node and AV node.
They lack functioning fast channels.
That's why depolarization is so slow in them.

So what will happen if fast fibers lose their fast sodium channels?
They'll convert into slow fibers!

When does this happen? @_@
When the resting membrane potential is less negative.

Why does this happen?
Less negative potential inactivates sodium channels.
Repolarization is necessary for returning the sodium channels to the ready state.

So.. what will depolarize a slow fiber?
L type Calcium channels! =D
Also known as slow channels.
They allow sodium to pass as well.
It's known as the sodium window current.
So you can appropriately call em slow calcium sodium channels.

Other ways of saying the same thing but worth noting:
Capacity of a cell to depolarize depends on the number of sodium channels in ready state.
The more negative resting potential, the faster the response.
(-90mV in atrial and ventricular cells, compared to -60mV in pacemaker cells)
Slow response fibers have no appreciable Na+ current during phase 0 in these cells because the Na channels are either absent or in an inactivate form because of the existing voltage (-60mV, remember?)

That's all!
^______^
-IkaN

Thursday, April 11, 2013

Behind the scenes: Subendocardial fibres lack phase 1

Hello everyone!

I know my "Why are there differences in cardiac action potential in different parts of the heart?" post is not like the regular posts where I tell the usual facts and mnemonics and it seems out of place.

So I thought of doing a behind the scenes version of it. Who said only videos have behind the scenes? Each writing, each painting, each piece of art has a behind the scenes!

Let's get to it =D

Behind the scenes of:

Why are there differences in cardiac action potential in different parts of the heart?


My quest started off with the statement, "Subendocardial fibres lack phase 1"
And when you Google "Subendocardial fibres" it tells you about "Purkinje fibers" which is not the same.


The lord is testing me
"Why do subendocardial fibres lack phase 1?" seemed impossible to answer at first!
"Quit, don't quit? Noodles, don't noodles? You are too concerned about what was and what will be." —Oogway (Kung Fu Panda)
I decided to keep going. After poking around here and there I discovered that purkinje fibers have a prominent phase 1. That means subendocardial fibers can NOT be purkinje fibres.

The heart cells in the subendocardial region lack phase 1 and the conducting cells (Purkinje fibres) in the same region have a prominent phase 1.
I believed there was beauty in how it was created. How our bodies are designed. But I didn't know why.
"What a piece of work is a man! How noble in reason, how infinite in faculty! In form and moving how express and admirable! In action how like an angel, in apprehension how like a god! The beauty of the world. The paragon of animals. And yet, to me, what is this quintessence of dust?"
—Shakespeare
I had to push further to find out why..

I learnt there was a difference: Cells in different regions of the heart do not have the same action potential. We have a tendency to generalize things and principles to everything. The statement was a mind opener for me!
"We are all equal in the fact that we are all different. We are all the same in the fact that we will never be the same. We are united by the reality that all colors and all cultures are distinct & individual. We are harmonious in the reality that we are all held to this earth by the same gravity. We don't share blood, but we share the air that keeps us alive."
 ― C. JoyBell C.
I learnt why was there a difference: The repolarization phenomenon being different in every cells. Repolarization in a cell occurs because the action pulse has only a certain duration; thus the cell repolarizes at a certain instant of time after its depolarization, not because of the repolarization of an adjoining cell.

Because it's the differences make life interesting!
"Sunshine is delicious, rain is refreshing, wind braces us up, snow is exhilarating; there is really no such thing as bad weather, only different kinds of good weather."
― John Ruskin
Then I learnt what causes the difference: The potassium channels conductance. The action potential notch is due to the presence of a transient outward current (Ito), which diminishes in amplitude from the epicardial to endocardial surfaces.
"There is little difference in people, but that little difference makes a big difference. The little difference is attitude. The big difference is whether it is positive or negative." 
― W. Clement Stone
I learnt why is that necessary: Help the heart contract in an organized fashion and prevent haywire spread of cardiac excitation.
"You can become blind by seeing each day as a similar one. Each day is a different one, each day brings a miracle of its own. It's just a matter of paying attention to this miracle."
 ― Paulo Coelho
In the process I also learnt that without something pushing you to find the answers it's just impossible to keep looking. Thank you for being my reason.
"Passion rebuilds the world for the youth. It makes all things alive and significant."
 ―Ralph Waldo Emerson
 And that's how I ended up finding my answers to the all my questions. It took me three days of asking and three hours of Google search to get to my answer. And I'd like to end by quoting the last quote on hard work :D
"So if you wanna do something, if you've thought about something you wanna do, take it head on. Decide that you're gonna face it; that whatever shortcomings you have, that you're gonna stiffen yourself there; whatever training that is required, that you're gonna get that training; that you're gonna get started right now; do what you can, where you are, with what you have and never be satisfied."
 ― Les Brown
That's all!
Hope you had fun learning with me and see you in the next post xoxo
-IkaN

Wednesday, April 10, 2013

Why are there differences in cardiac action potential in different parts of the heart?

Cells in different regions of the heart do not have the same action potential.

The difference is major between conducting system and the myocytes.
And there is a minor variation in the action potential in distinct parts of the ventricle (endocardial and epicardial)

What is epicardium and endocardium?
Epicardium is the outer side of the cardiac muscles and endocardium is the inner side (towards the cavity of the ventricle)

What causes the difference in action potential?
This is due to the nature of repolarization.
Unlike depolarization, the repolarization is not a propagating phenomenon.

When a cell depolarizes, another cell close to it then depolarizes and produces an electric field which triggers the depolarization phenomenon.
In this way, the depolarization proceeds as a propagating wave within cardiac tissue.

Repolarization in a cell occurs because the action pulse has only a certain duration; thus the cell repolarizes at a certain instant of time after its depolarization, not because of the repolarization of an adjoining cell.

If the action pulses of all cells are of equal duration, the repolarization would of course accurately follow the same sequence as depolarization.
In reality, however, this is not the case in ventricular muscle. The action pulses of the epicardial cells (on the outer surface) are of shorter duration than those of the endocardial cells (on the inner surface).

Coming back to our original statement.. What is the minor variation in the action potential of endocardial and epicardial fibres?

The epicardial action potential exhibits a prominent notch between phase 1 and phase 2 that results in a spike and dome configuration. The notch is smaller in midmyocardial cells and absent in endocardial cells.
Subendocardial fibres lack phase 1.
The action potential notch is due to the presence of a transient outward current (Ito), which diminishes in amplitude from the epicardial to endocardial surfaces.

This current is due to potassium efflux (potassium going out of the cell)
You see, if the sodium channels simply closed at phase 0 the action potential would stay up there. It is the closure of potassium channels which cause the repolarization and the phase 1.

It simply means epicardium has more outward current than endocardium.
Outward potassium current is little in endocardial cells.
So very little potassium is going out.. And that too is balanced by calcium coming in. That's why no phase 1. Hope that made sense ^_^"

In real heart muscle, since the action potential duration at the epicardium is actually shorter than at the endocardium, the recovery phase appears to move from epicardium to endocardium, that is, just the opposite to activation.

Why is there a difference in action potential?
According to me, the differences in action potentials cause a difference in conducting velocities and difference in refractory period (changing their respective response to stimulation rate)
It is these differences that help the heart contract in an organized fashion and prevent haywire spread of cardiac excitation.
I mean, we don't want the impulse transmitted to the epicardium from the endocardium go back into the endocardium now, do we?
So we let the epicardium repolarize first (shorter action potential) and make sure that the endocaridum is refractory till then.
Otherwise we'd have an impulse going back and forth from the epicardium to the endocardium!

That is why, during depolarization, the impulse is carried from endocardium to epicardium, and during repolarization, the impulse moves from epicardium to endocardium.

What helps one of my best friend's remember this is "What depolarizes last, repolarizes first"
So to sum it all up, it's the variation in potassium (potassium conductance) which plays a major role in impulses going here and there in the heart. That's why potassium injections are lethal if not in range.
Thank you so much for being there in my life (:

Cool fact: 
Purkinje fibres have a prominent phase 1.
The heart cells in the subendocardial region lack phase 1 and the conducting cells (Purkinje fibres) in the same region have a prominent phase 1.
It is breathtakingly beautiful how our body is designed :)

Another cool fact: The changes in action potential also change the response of various drugs on different parts of the heart. This I came to know during my extensive Google search :P
So all of these minor changes might have relevance in your future practice as a doctor =D

That's all!

If you search hard enough for something, you will find it.. Yes, even the answers to your silly questions! ^_^

Read behind the scenes, which questions lead me to which answers & making of this post by clicking here.

-IkaN

References: 
http://www.bem.fi/book/06/06.htm
http://cpt.sagepub.com/content/2/1/61.short
http://en.wikipedia.org/wiki/Endocardium
http://physrev.physiology.org/content/85/4/1205.full

Monday, April 8, 2013

Why does heart stop in diastole when plasma potassium level rises?

Normally, potassium has a tendency to move outside the cells due to the concentration gradient.

As plasma potassium rises, this concentration gradient is reversed. 
So potassium will move into the cells. 

The cell's resting membrane potential is very sensitive to changes in extracellular potassium ion concentration.
Elevated potassium, or hyperkalemia, causes the resting electrical potential of the heart muscle cells to be lower than normal (less negative). 

Without this negative resting potential, cardiac cells cannot repolarize. 

That means all your cells are depolarized.
This inactivates sodium channels. 

Inactivated sodium channels means the cells can not fire. 
The heart can not contract. 
That's why, heart stops in diastole. 

Hope you understand :)

This is the mechanism of execution by lethal injection, sudden depolarization of the cell without the ability to repolarize.

Increased extracellular potassium is also seen in rhabdomyoloysis, tumor cell lysis, hemolysis etc.

Cool fact:
In ischemic tissue, potassium in the surrounding interstitium rises. 
Wanna know why?
Ischemic tissue does not receive oxygen.
So there is lack of ATP.
Na+ - K+ ATPase doesn't work
K+ leaves the cell and no one can pump it back in.
(Special thanks to a friend for explaining this fact to me ^_^ )

Another cool fact:
Increased extracellular calcium tend to stop the heart in systole (contracted).
This is known as calcium rigor.

That's all!

-IkaN


Sunday, April 7, 2013

Cerebellum mnemonics

Hello everyone!
This post is for those having trouble remembering the cerebellum

I modified a mnemonic I got online :)
So if you have a little bit of anatomic imagination cerebellum should be a piece of cake for you!


Region: Hemisphere (lateral)
Principle input: Cerebrocerebellar
Function: Peripheral coordination and planning
How to remember: It’s location is around the periphery of cerebellum

Region: Flocculonodular lobe
Principle input: Vestibulocerebellar
Function: Ear, eye, balance, body co-ordination.
How to remember: Pops out to the edges, looks like bunny ears to me =P

Region: Vermis
Principle input: Spinocerebellar
Function: Axial equilibrium
How to remember: It is located in the axis of cerebellum
And looks like the spinal column

Also, the intermediate hemisphere influences the lower motor neurons via the rubrospinal and reticulospinal tracts

I think of climber plants and the fruit olive
And that's how the "climbing fibres" and "olivocerebellar tracts" come together xD

Superior Sends out
Superior cerebellar peduncle in the major outflow from the cerebellum

That's all the mnemonics I got
Feel free to add more in the comments ^__^

-IkaN


Thursday, April 4, 2013

Spinal cord organization mnemonic

Hello, all my Pokemon and cat fans =P

Spinal cord organization mnemonic
“SAD MEW”

S - Sensory
A - Afferent
D - Dorsal

M - Motor
E - Efferent
V V - Ventral


"Sad mew" Spinal cord organization mnemonic

-IkaN

Wednesday, April 3, 2013

Cochlear nerve, pathway and mnemonic

It's time to finish off the cochlear part of the vestibulocochlear nerve! :)

It starts off from the organ of corti, central processes of the spiral ganglion forms the cocchlear nerve and they terminate into the cochlear nuclei

From the cochlear nucleus, most of the axons cross to the opposite side in the trapezoid body and terminate in the superior olivary nucleus

The axons arising from the superior olivary nucleus form the lateral leminiscus
and reach the inferior colliculus

The fourth neurons pass through the inferior brachium to reach the medial geniculate body

The axons of the fifth neurons form the auditory radiation which passes through the sublentiform part of the internal capsule to reach the auditory area in the temporal lobe

How am I ever gonna remember all this? @_@
Mnemonic! =D
SLIM
S = Superior olivary nucleus
L = Lateral leminiscus
I = Inferior colliculus
M = Medial geniculate body

I sorted out the whole pathway for you :P

Now, all you need to remember is that lesion in the cochlear part of the 8th nerve of the cochlear nucleus will cause a unilateral sensorineural hearing loss
Because fibres haven't crossed yet

If it is a bilateral senorineural hearing loss, the lesion is at higher levels such as the brainstem, thalamus or cortex
These patients will also have a decreased ability to localize a sound source


I'll add the mnemonic for the auditory tests here too

W, for Webers test, is a symmetrical alphabet ie made up of two V's
So it tests both ears simultaneously
Also, tuning fork is placed on the Vertex

R, for Rinnes test, is asymetrical
Tests only one ear
It's kinda stupid but works for me :)


That's all!
-IkaN

Vestibular nerve, pathway and mnemonic for the receptors

Hello everyone! We'll finish off the vestibulocochlear nerve today :)
It isn't as hard as it seems, trust me <3

Vestibular receptors are:

The macuLae of the utricLe and saccuLe
And what do they sense? Linear acceLeration

The Cristae of the semiCircular canal
And what does it sense? Circular movements (rotatory)

It's a no brainer really =D

Sunday, March 31, 2013

Lipoproteins and apoproteins

Hey guys!
We have always had difficulty remembering lipoproteins and apoproteins and stuff.. And what makes it simpler? Mnemonics!

After you eat, dietary trigylcerides is transported via chylomicrons from the intestine to the adipose tissue.
VLDL carries endogenous triglycerides from the liver to the peripheral tissues.

Both triglyceride transporters contain apoB

Chylomicrons have micro
Micro means small
So they have a small number, that is, apoB 48

VLDL have the larger number, apoB 100

apoC II is a Cofactor for lipoprotein lipase
Which hydrolyzes the triglycerides into fatty acids and glycerol
LIpoprotein LIpase is activated by InsuLIn

apoE helps in rEmnant uptake by lEvEr (Liver =P )

Chylomicron (B48, C-II, E) > Chylomicron remnant (B48, E)
 

VLDL (B100, C-II, E) > IDL (B100, E) > LDL (B100)
VLDL loses apoC-II to become IDL
IDL loses apoE to become LDL
LDL will transport cholesterol to peripheral tissues

apoA-I Activates lcAt (LCAT)
Also, I looks like l
It's on HDL
Converts cholesterol to cholesterol esters
(LCAT transfers a polyunsaturated fatty acid from 2nd carbon of glycerol to cholesterol forming lysolecithin and cholesterol ester)

*phew* That was work!
Let's have a look at the deficiencies now =)

So what happens if you have apoB deficiency?
No triglycerides is incorporated into VLDL and chylomicrons
Serum triglycerides, cholesterol and phospholipids are low
Beta lipoprotein (LDL) is absent
Lipids and lipid-soluble vitamins (especially A and E) are poorly absorbed (steatorrhea)
Hemolytic anemia—lipid imbalance causes RBC membranes to pucker (acanthosis)

What happens in lipoprotein lipase deficiency?
Increased triglycerides in chylomicrons and VLDL!
(You can't breakdown triglycerides to fatty acid and glycerol for uptake)

What happens if you have a LDL receptor deficiency?
There will be and increased levels of LDL and cholesterol
(Because peripheral tissues can't take them without the LDL receptor)

What happens if you have LCAT deficiency?
You have increased unesterified cholesterol
(You can esterify the cholesterol you have)
You also have increased phoshatidyl choline which is a component of lecithin

That's all!
 Have an awesome week <3

-IkaN

Post is continued here

Southern, Northern, and Western blot mnemonic

Hello everyone!

The mnemonic to remember blotting techniques is "SNoW DRoP"

S -    Southern - DNA     - D
N -   Northern - RNA     - R
O -   Oooooo - Ooooo    - O
W -  Western - Protein   - P


Blotting techniques illustration and mnemonic :)
There's another simpler one for all those who can speak the language Hindi.. Southern in Hindi is Dakshin for DNA & Western in Hindi is Paschim for Protein!

Cool facts on blotting techniques that the mnemonic doesn't cover -
If you want to visualize DNA at replication level, you will use Southern blot. This will require a DNA probe attached to phosphate.
RNA at transcription level can be visualized with Northern blot. This will require a DNA probe attached to phosphate too.
Remember: If you want to visualize protein at transcription level, you will go with Northern blot!
Proteins at translation level are just antigens (Whether they are cell membrane, cytoplasmic or secretory proteins!) Therefore, antibodies (not probes) are used to visualize proteins byWestern blot.
DNA binding proteins also known as transcription factors go to the nucleus and bind to DNA. They are proteins but they work at the DNA level. They are different than just regular antigens and therefore, we use DNA probe (not antibodies!) to visualize them. This is known as the South Western blot :)

That's all!

Hope you won't go, "Which direction was that again?" in the exam =P

-IkaN

Updated on 4th December, 2013: Hindi mnemonic & illustration.
Updated on 5th December, 2013: Cool facts that you may have not known.

Sunday, March 24, 2013

Leukocyte adhesion deficiency mnemonic

Leukocyte adhesion deficiency mnemonic

Chemokines (chemoattractants) mnemonic

Here is something for chemoattractants..

Phagocytic cells are in blood vessels which is like street of city
Now they want to go in tissues which is like a dark forest

Somebody suggested phagocytic cells that if you want to go,
"Before (B4) going, make sure you can See five (C5a) clearly In Light (IL8) and form peptides (N-formyl peptides)"

So it is B4, C5a, IL8, N-formyl peptides.

-IkaN

HLA, MHC & CD T cell mnemonic

Hello everyone!
Time for another immmunology mnemonic =D

MHC class I:
CD8+ T-cells recognize MHC I.
It takes only 1 stroke of the pen to write “8

The genes have only one alphabet. (HLA-A, HLA-B, HLA-C)

CD8 x MHC1 = 8
CD8+ are Cytotoxic T cells because "EighT" has T for "Toxic"

All cells have one nucleus, so all nucleated cells have class I MHC.

MHC I has one chain (alpha chain) & one microglobulin (Beta 2 microglobulin).
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