SHIKSHA FOR ALL

HOW STRESS CAN MAKE YOU SICK Cramming for a test trying to get more done than you've time to do stress is a feeling we all experience. when we are challenged or overwhelmed but more than just an emotion stress is a hard wired physical response that travels throughout your entire body in the short term stress can be advantageous but when activated too often or too long your primitive fight or flight stress response not only changes.  Your brain but also damages many of the other organs and cells throughout Your body your adrenal gland releases the stress hormones cortisol epidemic fran also known as adrenaline and Nora E. B. ineffably as these hormones travel through your bloodstream they easily reach your blood vessels and heart adrenaline causes your heart to beat faster and raises your blood pressure over time causing hypertension. Cortisol can also cause the endothelium or inner lining of blood vessels to not function normally scientists now know that this is an earl...

AXIS HYPERSOMNIA Axis Hypersomnia is a chronic neurological sleep disorder that leads to daytime sleepiness and/or long sleeping hours for over 9-10 hours in 24   hours,  Hypersomnia means excessive daytime sleep or when you spent excessive  time sleeping. You will often feel exhausted and find it it hard to stay awake  during the day. There are times when you will feel the need to sleep all day, even after taking sufficient sleep. People who have hypersomnia can fall asleep at any time, for instance, at  work, while they are driving or while performing any other activities. Some  other conditions may also include sleep-related problems, lack of energy,  and trouble thinking clearly. REAL LIFE CASE A 42-year-old man from Rajasthan's Nagaur district sleeps 300 days a year and has been dubbed as the real-life 'Kumbhkarna', the mythological character from Ramayan, famous for sleeping undisturbed for six months.  Pukharam, a resident ...

CYTOPLASM AND ITS ORGANELLES 1. ENDOPLASMIC RETICULUM (ER)  It is a complex series of tubules whose walls are made up of unit membrane. Through this network of tubules, substances may be deli vered from the outer membrane of cell proper to the membrane of the nucleus or to other inclusion bodies of the cells e.g. mitochondria: (i) Agranular or Smooth ER: Contains no granules. (a) It is site of steroid (Adrenocortical hormone) synthesis in steroid secreting cells and the site of detoxification processes in other cells. (b) As the sarcoplasmic reticulum, it plays important role in skeletal and cardiac muscles. (ii) Granular or Rough ER or Ergasto plasm. (a) Contains granules called ribo somes (diameter 15 nm; contains 65% RNA and 35% protein - Ribo nucleoprotein) which are attached to the cytoplasmic side of the membrane. 3-5 ribosomes clump together to form polyribosomes or polysomes. (b) It is the site of protein synthesis e.g., hormones that are secreted by the cel...

NUCLEUS AND ITS CHROMOSOMES Structure 1. It is a spherical structure (10 μm dia meter) surrounded by a relatively permeable membrane called nuclear membrane (or envelope). This is composed of two unit membranes and show large pores of 1000 Å diameter which are closed by thin homogenous membrane. Therefore, passage of macromolecules like RNA can take place through these pores. The space between the two folds is 300 Å and is called Perinuclear Cistern. 2. It is made up of chromosomes (each chromosome is made up of supporting protein plus giant molecule of Deoxyribonucleic Acid DNA), on which genes are present. Gene is a portion of DNA molecule which carries a complete blue print for all the heritable species and individual characteristics of an animal. During cell division, the pairs of chromosomes become visible, but between cell divisions the irregular clumps of dark material called chromatin are the only evidence of their presence. 3. It contains a nucleolus which is...

CELL MEMBRANE OR PLASMA MEMBRANE The fundamental unit of life is a cell, since virtually all tissues and any organised activity can be equated to the cellular level. THICKNESS:  70-100 Angstrom (A) or 7-10 nanometer  (nm) (1 nm = 10^-9 mts; 1A = 10^-10 mts). STRUCTURE (FLUID MOSAIC MODEL) 1. All membranes consist of a double layer of lipid molecules in which proteins are embedded. 2. Proteins make up 50% of the mass of the membrane and is of 2 types: (i) Lipoproteins (proteins  containing lipids): function as enzymes and ion  channels. (ii) Glyco-proteins (proteins containing carbohydrates): function as receptors for hormones and neurotransmitters. Some proteins are located in the inner surface of the membrane (intrinsic proteins) ; some are located in the outer surface of the membranes (extrinsic or peripheral proteins); while some extend through the membrane (transmembrane proteins): (i) Intrinsic proteins serve mainly as 'enzymes'. (ii) Extrinsic...

COMPOSITION OF BLOOD Total blood volume : 5-6 litres (8% of body weight or 80  ml/kg body weight) Specific gravity : 1050-1060 Viscosity : 4-5 times that of  water  PH : 7.4 ± 0.05; alkaline If anticoagulated sample of blood is allowed to stand in a narrow tube, on settling it separates out into cells and plasma. CELLS The cellular elements of blood represents 45% of the total blood volume, called Packed Cell Volume (PCV) or Haematocrit. It  includes: 1. Erythrocytes  or Red Blood Corpuscles  (RBC's) Normal count: 5 million/cumm (5 x 10 per cumm). 2. Leucocytes  or White Blood Corpuscles  (WBCs) Normal count: 4,000-11,000/cumm (4-11 x 10³ per cumm). 3. Platelets  or Thrombocytes Normal count: 1.5-4 lacs/cumm (0.15-0.4 x  10° per cumm). PLASMA 1. Plasma is a clear, straw coloured portion of the blood and represents 55% of  the total blood volume. It contains: (i) 91% water; and (ii) 9% solids. The solids comprises of:...

RBC is a circular, biconcave, non nucleated disc. Advantages of biconcave disc: (i) Allows considerable alteration in cell volume. Thus, can withstand consider able changes of osmotic pressure resist hemolysis. and (ii) Allows easy folding of RBC on itself when it passes through capillaries. (iii) Haemoglobin remains distributed in the centre of the RBC which facilitates optimal and quick exchange of gases (i.e. oxygen and carbon dioxide). The mature RBC has no nucleus, no mitochondria and no ribosome, still it can live for 120 days and can carry out its normal activities. How? RBCS depend entirely on glucose metabolism for its energy supply.Glucose is transported easily across the cell membrane by facilitated diffusion (i.e. carrier mediated passive process). Although the cell has no mito chondria but it has cytoplasmic enzymes for metabolizing glucose and other substances and for utilization of oxygen. As these metabolic systems become progressively less active with time...

Monkey B Virus led first human death reported in China - Is  B deadlier than Coronavirus? WHAT HAS HAPPENED? As the world grapples with the devastating Covid-19 pandemic, a new viral infection has been reported in China.  The Monkey B Virus (BV) claimed its first victim in the country after a veterinary surgeon contacted the virus while dissecting two animals. The victim, a 53-year-old veterinarian based in Beijing, was the first documented human case of the virus in China. HOW THE CASE WAS DETECTED? The surgeon was infected with the virus after he dissected two  dead monkeys in early March. Later he started experiencing nausea and vomiting and a month later, fever and neurological symptoms followed. He visited several hospitals but eventually died on May 27,  China CDC Weekly revealed Saturday. Around mid-April, researchers collected cerebrospinal fluid from the patient for next-generation sequencing and the readings suggested possible alphaherpesvirus i...

Platelets or Thrombocytes (Platelets =small plate; thrombo = lump or  clot; cytes = cells) 1. Platelets are the smallest blood cells, colourless, spherical, oval or rounded granulated bodies;  2. 2-5 µm in diameter with an average volume 5.8 μm³;  3. Leishman staining shows a faint blue cytoplasm with distinct reddish purple granules; nucleus is not present. THROMBOPOIESIS or MEGAKARYO-CYTOPOIESIS i.e. DEVELOPMENT OF PLATELETS Site of origin: bone marrow Steps : Pluripotent stem cell                      ↓ Committed stem cell  (polyploid precursor cell)                     ↓ Megakaryoblast (Stage I)                     ↓ Pro-megakaryocyte (Stage II)                     ↓ Granular megakaryocyte  (Stage III)            ...

The different types of leucocytes present in the circulation are: A. Granulocytes i.e. WBC with granules in  their cytoplasm                                     Percentage             Absolute count 1. Neutrophils.             50-70%                3000-6000/cumm 2. Eosinophils                1-4%                  150-300/cumm 3. Basophils                   < 1%                  10-100/cumm B. Agranulocytes (Agranular) 1. Lymphocytes.        20-40%               1500-2700/cumm 2. Monocytes              2-8%...

WHO Emergency Committee warns about spread of more dangerous Covid variants WHAT HAS HAPPENED? The World Health Organization's emergency committee on Covid-19 on Thursday warned that the pandemic was not over and that it continued to evolve with four variants of concern. WHAT THE EMERGENCY COMMITTEE SAID? "The committee recognised the strong likelihood for the emergence and global spread of new and possibly more dangerous variants of concern that may be even more challenging to control," the panel said in a statement. The committee said that the pandemic was still an "extraordinary event" that continues to hurt public health, and needs a coordinated international response. The statement also said that the committee emphasised on the risk of emergency of new zoonotic diseases during the pandemic.  Zoonotic diseases are caused by germs that spread between animals and people, according to United States' Centers for Disease Control and Prevention.  A...