+ Health and Sciences +

Area outside the Blood brain barrier are called Circumventricular organs Mnemonic - M arble SOAP M edian eminence S ub fornical organ O rganum vasculosum A rea postrema P osterior Pitutary

Blood volume in lungs= 450ml, 9% of total blood volume. Blood flowing through Bronchial arteries- 1-2% of total Cardiac Output Pulmonary Vascular resistance= 1/7 of systemic vascular resistance Mean pressure= 15mmHg Pulmonary arteries constrict in response to hypoxia. Perfusion and Ventilation both are more in lower lobes Ventilation/resistance is maximum at the apex. Pulmonary veins are collapsed in upper and middle lobes, distended in lower lobes. This is because pressure in pulmonary veins of upper and middle lobes is less than atmospheric pressure. This causes the veins to collapse.

SA node: Sino-Atrial node is located at the junction of superior vena cava with right atrium, Just deep to the epicardium, near the sulcus terminalis. The SA node is made of modified cardiac muscle that has fewer strations and indistinct boundaries. These cells are small round with few organelles which are connected by gap junctions. These cells are called P cells (pacemaker cells). SA node is the fastest discharging part of the myocardium (70 to 80/min) Blood supply of SA node- Right coronary artery supplies the SA node in 65% of the cases. Nerve supply- SA node develops from the structures on the right side of the embryo, therefore SA node is supplied by Right vagus nerve and Right sympathetics. Noradrenergic nerve fibers are epicardial while vagal fibers are endocardial. AV node: Atrio-ventricular node is located in the right postero-infero region of the interatrial septum near the opening of coronary sinus. There are 3 bundles of fibers that connect the SA node with the AV node. Na...

Acne Vulgaris : Acne vulgaris is a self limiting disorder of teenagers and young adults.But 10-20% of adults may continue to experience this disorder. In adolescence, there is increased secretion of sebum from sebaceous glands. The glands get blocked with the retained sebum and kerotinous debris. Small cysts called Comedons are formed due to blockage of hair follicles. Proprionobacterium acnes is the cyst and caused production of fatty acids within the cysts. Thus causing infection of the cyst and bursting of the cyst wall. The extrusion of oily, keratinous debris triggers a foreign body reaction develops. Comedones : These are of two types- Closed comedones = White heads. Opened comedones = Black heads. The closed comedones are mostly associated with inflammatory lesions like papules , cysts and nodules. These are seen as small white heads with the naked eye or sometimes are not visible to the naked eye. The Open comedones are seen as Black heads. These are more st...

Pemphigus vulgaris is a blistering autoimmune skin lesion mostly seen in elderly patients.The disorder is characterised by a process called Acanthoysis (loss of cohesion between epidermal cells).Lesions are mostly flaccid blisters over the skin.These blisters burst out and the surounding skin gets denuded.In severe cases, substantial portions of the body get denuded.Manual pressue over these blisters can cause separation of epidermis.This is known as Nikolsky's sign. This finding is a characteristic feature of Pemphigus vulgaris but not the specific feature. Nikolsky's sign is also seen in Stevens Johnson Syndrome, Toxic epidermal necrolysis and few other skin conditions. Clinical Features: Sometimes the disorder starts with pruritis(itching).Lesions in Pemphigus vulgaris are usually seen over the oral mucosa, scalp, axilla, trunk, face, neck .Blisters are usually seen in the mouth first and then on other mucosa (pharyngeal, laryngeal, oesophageal, conjunctival, vulval or r...

Iron deficiency anemia is a condition where there is anemia and a clear evidence of iron deficiency. It is categorized under ‘Hypoproliferative Anemias’. Stages: Stage of negative iron balance – The demand (or loss) for Iron exceeds that of the body’s capacity to absorb from the diet. Most common causes of the above condition are pregnancy, blood loss from bleeding, growth spurts in adolescence. Blood loss of 25-30 micrograms/dL can exceed the total body’s capacity to absorb iron from diet. The iron from reticulo-endothelial system and other iron stores is utilized. In this condition, iron in stores like ferritin or stainable iron in bone marrow decrease. As long as iron stores are present and mobilized, serum iron, total iron binding capacity (TIBC) red cell protoporphyrin levels remain normal. At this stage, RBC morphology and indices are normal. Stage of Iron deficient erythopoiesis – When the iron stores are depleted, TIBC and red cell protoporphyrin levels increase. Marrow i...

Panic disorder is a type of anxiety disorder. Anxiety - Is defined as "Subjective sense of unease, dread or foreboding, can indicate a primary psychiatric disorder or can be a component of, or a reaction to a primary medical disease. Panic disorder - Defined as recurrent and unpredictable panic attacks which are distinct episodes of intense fear and discomfort associated with a variety of physical symptoms including palpitations, sweating, trembling shortness of breath, chest pain, dizziness and a fear of impeding doom or death,Paresthesias, gastrointestinal distress, air hunger and feelings of unreality are common. First attack is usually outside the home.Onset is usually in late adolescence to early adulthood.Anticipatory anxiety occurs in some people leading to generalized fear and avoidance of places or situations where panic attack may recur. Panic attack occurs suddenly over a period of 10 mins and resolving over a period of one hour.The attacks usually occur in an unexpec...

Most common form of Facial paralysis. Clinical features : Pain behind the ear may preced the palsy for one or two days. Onset is abrupt and maximal weakness is attained by 48 hours. Loss of taste sensation unilaterally (on one side). Hyperacusis may be present. Mild cerebrospinal fluid Lymphocytosis may be present. Presence of incomplete paralysis in first week is most favorable sign. 80% patients recover in few weeks to months. Pathophysiology : Bell's palsy is associated with presence of Herpes Simplex type I DNA in endonueral fluid and posterior auricular muscle.This indicates that reactivation of this virus may have some role.However this is not proven yet. Differenctial Diagnosis : Other causes of Facial Palsy - 1. Tumours of temporal bone - Carotid body tumor, Cholesteotoma, Dermoid cysts.The course is insidious and progressive. 2. Ramsay Hunt Syndrome - Due to Herpis zoster of geniculate ganglion.Consists of : Severe facial palsy; eruptions in pharynx, external auditory ca...