There are three types of  ion channels in cells of human body. They are as follows: 1. Ungated Ion Channels or leak channels     These channels are always open and there is free diffusion of ions through these channels along the concentration gradient of the ions. Leak channels are responsible for maintenance of Resting membrane potential of a cell. 2. Voltage gated Ion Channels Voltage gated ion channels respond to the change in resting membrane potential of the cell. These channels either open or close based on the voltage of the resting membrane potential. 3. Ligand gated ion channels These ion channels have a additional binding site for ligands and open or close based on weather the ligand is attached or not. Ligands act as keys and the channels act as locks.   A receptor can act as one of the types. NMDA receptor is an exception. NMDA receptor can act both as voltage gated and ligand gated channel.

  X-ray : basic interpretation X rays are one of the most frequently requested investigations and their interpretation is one of the fundamental skills of every doctor. In this blog series, we look into the basic interpretation of chest x-ray. If you have no or little knowledge regarding the interpretation of x rays   then it will give you a solid foundation upon which you can build your further knowledge. figure. x-ray source, detector, patient in between less dense like air=black,  more dense like bones=white,  moderate dense like water=grey   parts of the film -                 where x ray struck: black     where x rays are blocked/ no x ray struck: white     where some amount of x ray struck: shade of grey spectrum: radiolucent to radiopaque ( air, fluid, and soft tissue, bone, metal) there are 3 types of views for x ray:  ·  ...

  Syncope An abrupt loss of consciousness or loss of postural tone which is of short duration and is followed by spontaneous recovery is known as syncope.  There are four components of syncope An abrupt and transient loss of consciousness  Loss of postural tone Short Duration Spontaneous recovery Prodrome A constellation of symptoms like lightheadedness, diaphoresis, visual distrubances that can  precede the loss of consciousness. Prodrome can last for several seconds to minutes.     Chest pain, palpitations or dyspnea point to cardiac cause     Aura , Headache, Dysarthia, and limb weakness point to CNS causes Pre-syncope Occurance of prodromal symptoms of syncope without the subsequent loss of consciousness is known as pre-syncope. During Attack Is there a pulse? Limb jerking, Tongue biting, Urinary Incontinence? Hypoxic Seizures After Attack Rapid recovery: Arrythmia, VAsovagal syncope Prolonged, with drowsiness: Seizures Questions to...

 How are Shingles and Chickenpox related? If you remember someone or yourself getting chickenpox as a child then you might know that it causes skin rashes. Chickenpox is caused by a virus known as varicella-zoster. The virus is highly contagious and causes an itchy rash that affects the whole body. You can get singles later in life if you have had chickenpox in childhood. As someone recovers from chickenpox their body is never completely free of the virus. Instead, the virus stays inside the body in the less active or dormant form inside the nerves. In some people, the virus remains harmlessly for the rest of their lives. While in other people the inactive virus can suddenly get active and cause the disease again. This time the disease is known as shingles. What is the difference between the rash of chickenpox and shingles? Similar to chickenpox, shingles also causes a vesicular rash but it does not involve the whole body. The rash of shingles is more localized to an area of the bo...

Loop and thiazide diuretics have common clinical uses like in the treatment of hypertension, heart failure, edema, etc. But they have different actions in calcium excretion or retention. Loop Diuretics like Furosemide, Torsemide work by inhibiting Na+/K+/2CL- transporter in the thick ascending limb of the loop of Henle. Inhibition of this co-transporter causes loss of sodium, potassium into the urine, and drives loss of water. It also results in loss of lumen positive potential and decreases reabsorption of divalent ions like calcium. Thus there is increased loss of calcium in the urine.    Thus loop diuretics can be used in the treatment of hypercalcemia.     But they increase the chances of developing kidney stones. Thiazide diuretics like hydrochlorothiazide work by inhibiting NaCl transport in the early segment of DCT. Thus reduce intracellular sodium and increase the exchange of sodium and chloride in the basolateral membrane. Thus they increase calcium r...

What is Buerger's Disease/ Thromboangitis Obliterans? Buerger's disease or Thromboangitis Obliterans is a rare disease that affects veins and medium sized arteries of your hands and feet.   These blood vessels get inflamed and obstructed. Decreased blood flow causes ischemic pain known as claudication. In later stages there is death of cells and tissue in the area causing ulcers, gangrene and can also lead to amputation of hands and fingers.   What is the cause of Buerger's Disease? The cause of Buerger's disease is not known. But it is almost always   a disease of smokers.   The patient is usually a male smoker in his 20s or 30s. The symptoms are claudication, numbness, tingling. Raynaud phenomenon in which the fingers turn pale on exposure to cold can be seen. How is Buerger's Disease diagnosed?  There is no definitive test for diagnosis of Buerger's Disease. But a history of tobacco smoking, and younger age favours diagnosis. Physical ...

  The Bishop Score Score 0 1 2 3 Dilation of cervix in centimeters 0 1 or 2 3 or 4 5 or more Consistency Firm Medium Soft   Length <2cm 2-1 1-0.5 cm <0.5cm Position Posterior Central Anterior   Station of presenting part -3 -2 -1 or 0 Below ischial spines   What is the Bishop Score? The Bishop Score is a scoring system used to assess the cervix during induction of labour.   During labor, there is spontaneous softening, shortening, effacement, and dilation of cervix. Cervix also moves forward from posterior position to more anterior position.   Factors more favourable for labor are Dilated cervix Soft consis...

Different methods of induction of labour are: Membrane Sweeping This method is only performed at term and placenta previa is ruled out prior to the procedure. After cervix begins to dilate, a gloved finger is inserted through the cervix and is rotated around the inner rim of cervix. In this method chorionic membrane is stripped off from underlying decidua which causes release of natural prostaglandins.   Prostaglandin Prostaglandin is available in form of gel, pessary, or tablet. PG E2 is the most common formulation. It can be inserted vaginally into the cervix to ripen cervix and initiate contractions.   Artificial rupture of membranes Prostaglandin alone may not be sufficient for a successful induction of labour especially in primiparous women. In cases Artificial rupture of Membranes and Oxytocin are used.   Oxytocin Oxytocin can be used after rupture of membranes. It is   given in IV infusion as dilute solution.   3-5 cont...

  What is a preterm labour? Preterm labour is the onset of labour before 37   weeks of gestation.   The easy medical mnemonic for medical students for different causes of pre term labour is " Infected Weak MUM Has Pre-Term labour"   @ Infected & Weak MUM H as Pre-term labour   Infections   Weak Cervix   M ultiple Pregnancy & Uterine distension   U terine Anomalies   M aternal or Fetal Stress   H emorrhage   Infections: Chorionamnionitis is the infection of fetal membranes and is a major cause of Pre-term birth particularly in < 32 weeks.   Weak Cervix: Cervical weakness causes PAINLESS dilation of cervix and there is history of PAINLESS 2nd trimester pregnancy loss. Past history of cervical surgery is a major risk factor.   Multiple Pregnancy & Uterine distension : Uterine distension by multiple pregnancy or less commonly by polyhydra...

  Causes of Cushing's Syndrome are as follows:   Looking at causes of Cushing Syndrome on basis of plasma ACTH levels, later helps in understanding the approach to investigations performed in diagnosis of Cushing's disease .   First use of exogenous steroids should be ruled out. Iatrogenic use of steroids is common cause of Cushing's Syndrome. Exogenous steroids cause feedback inhibition of ACTH secretion.   If plasma ACTH level is undetectable and there is no exogenous use of steroids then the source of increased cortisol level is likely an adrenal adenoma/ cancer / hyperplasia . The feedback inhibition due to increased cortisol levels make ACTH levels undetectable.   If ACTH levels are increased then it means the cause of high cortisol levels is high ACTH levels. This increased ACTH is due to either pituitary cause or ectopic ACTH secretion .   What are causes of ectopic ACTH secr...

A 45-year-old woman presented with a two-day history of diarrhea, vomiting, progressive numbness around her mouth and generalized body cramps. She had undergone a total thyroidectomy for a multinodular goiter seven months back. Her vital signs were stable. Trousseau sign was evidenced a few seconds after the sphygmomanometer cuff was inflated to more than the systolic blood pressure on the left upper arm. What is the most likely diagnosis? Diagnosis is at the end of the article but first let's answer these questions           what is Trousseau sign?    and what is Chvostek sign? Signs of Hypocalcemia The Chvostek Sign is a clinical sign of existing nerve hyperexcitability (tetany) seen in hypocalcemia. It refers to an abnormal reaction to the stimulation of the facial nerve. When the facial nerve is tapped in front of tragus the facial muscles on the same side of the face will contract momentarily (typically a twit...

In the thalassemias, the synthesis of either the α- or the β-globin chain is defective. Imbalance in α- and β-globin synthesis leads to precipitation of excess goblin chain e.g. α4-tetramers in β-thalassemias                    β4-tetramers(HbH) and γ4-tetramers(Hb Barts) in α-thalassemias 3. (**Click on above image for better view on smartphones) Clinical Features of Thalassemias β-thalassemia minor and α-trait are often asymptomatic with mild microcytic and hypochromic anemia. β-thalassemia major: Decreased synthesis of goblin chain causes microcytic, hypochromic anemia, growth retardation and are sustained by repeated blood transfusions. "Target Cells" (so called because hemoglobin collects in the center of the cell) are common. Precipitation of α4-tetramers causes Extravascular hemolysis of mature RBCs Ineffectiv...