11th Class

The physiology of blood circulation was first described by Sir William Harvey in 1628. The blood circulation in our body is divisible into 3 circuits - (1) Coronary circulation : It involves blood supply to the heart wall and also drainage of the heart wall. (i) Coronary arteries : One pair, arising from the aortic arch just above the semilunar valves. They break up into capillaries to supply oxygenated blood to the heart wall. (ii) Coronary veins : Numerous, collecting deoxygenated blood from the heart wall and drains it into right auricle through coronary sinus which is formed by joining of most of the coronary veins. But some very fine coronary veins, called venae cordis minimae open directly in the right auricle by small sized openings called foramina of Thebesius. (2) Pulmonary circulation : It includes circulation between heart and lungs. The right ventricle pumps deoxygenated blood into a single, more...

Human respiratory system is derived from endoderm. Human respiratory system may be divided into two components- (1) Respiratory tract or conducting portion                           (2) Respiratory organs (1) Respiratory tract or conducting portion : It is the passage for the air. In this part gaseous exchange does not takes place. It is also called dead air space. It is divided in following parts*-answer-* (i) Nose (Latin-Nasa) (Greek-Rhine) : Cavity of nose is called nasal cavity. Nasal cavity is divided into two parts by nasal septum called mesethmoid. Each part is called nasal chamber. Each nasal chamber opens out side by external nares. Nasal septum has two part. First part is small and is made of cartilage (hyaline). Second part is major and it is bony. Vomer is the main bone. Each nasal chamber has three region. (a) Vestibular region : Vestibular region also known as vestibule, lined by non keratinized squamous epithelium, more...

In men the respiratory organ are a pair of lung. Some snakes have unpaired lungs. Respiration by lungs is called pulmonary respiration. Lungs are found in all vertebrates except fishes. In Lung fishes such as protopterus, neoceratodus and lepidosiren air bladder is found, which is modified lung. Respiration in men and rabbit is pulmonary. Lungs : Lungs lie in thoracic cavity on both side of heart in mediasternum space. Base of lung is attached to diaphragm. Right lung is divided into 3 lobes viz. Superior, Middle, Inferior and left lung is divided into two lobes Superior and Inferior. In rabbit, the left lung is divided into two lobes left anterior and left posterior where as the right lung has four lobes anterior azygous, right anterior, right posterior and posterior azygous. Lungs of reptiles are more complex than those of amphibians. In birds lungs are supplemented by elastic air sacs which more...

(1) Skin : Respiration by skin is called cutaneous respiration. Skin is the only respiratory organ in most annelids (earthworm and leeches) and an additional respiratory organ in amphibians (Toads and frogs). Skin should be thin, moist, naked, permeable and well vascular for respiration. For cutaneous respiration animal should have large surface area then its volume and should have relatively inactive life to minimize the use of oxygen. Some marine annelids such as sandworms (nereis) have parapodia (locomotory appendages) for respiration. In frog 100% cutaneous respiration during hibernatin. In all marine snakes 20% respiration by skin. (2) Tracheae : In insects, peripatus centipedes and millipedes tracheae are found for respiration. Tracheae are complex system of whitish, shining, intercommunicating air tubules. Tracheae are ectodermal air tubes. In cockroaches, three pairs of longitudinal tracheal trunks are present all along the length of body which are further connected with each other with the more...

Frog is an amphibious animal i.e. they are live in water as well as on land hence according to their adaptations they posses different modes of respiration, which are as follows - Frog is an amphibious animal i.e. they are live in water as well as on land hence according to their adaptations they posses different modes of respiration, which are as follows - (1) Cutaneous respiration : By the skin. Under water, during hibernation frog respires by only skin. On land cutaneous respiration continues as usual. Thus cutaneous respiration take place always. By cutaneous respiration frog fulfill its 30% need of oxygen. (2) Buccopharyngeal respiration : Like the skin, the mucosa of buccopharyngeal cavity in frog is also ideally adapted for gaseous exchange. Hence, while quietly floating upon water surface, and even when resting upon land, frogs respire by their buccopharyngeal cavity also. During this process, the mouth, gullet more...

Respiration is a process which involves intake of oxygen from environment and to deliver it to the cells. It include stepwise oxidation of food in cells with incoming oxygen, elimination of \[C{{O}_{2}}\] produced in oxidation, release of energy during oxidation and storing it in the form of ATP. It takes place in three basic steps - (1) Pulmonary ventilation : The first process, pulmonary (pulmo = lung) ventilation, or breathing, is the inspiration (inflow) and expiration (outflow) of air between the atmosphere and the lungs. (2) External (pulmonary) respiration : This is the exchange of gases between the air spaces of the lungs and blood in pulmonary capillaries. The blood gains \[{{O}_{2}}\] and loses \[C{{O}_{2}}.\] (3) Internal (tissue) respiration : The exchange of gases between blood in systemic capillaries and tissue cells is known as internal (tissue) respiration. The blood loses \[{{O}_{2}}\] and gains \[C{{O}_{2}}.\] Within cells, the metabolic reactions more...

The process of respiration is completed in 4 steps – (1) Breathing or ventilation          (2) Exchange of gases or External respiration (3) Transport of gases    (4) Cellular respiration (1) Breathing or ventilation : Movement of thorax, expansion (inflation) and deflation of lungs and flow of air into the lungs and from the lungs. It is extracellular, energy consuming and physical process. Sum of inspiration and expiration is called respiratory movement. There are two steps of breathing - (i) Inspiration : Intake of fresh air in lungs from outside. It is an active process. Blood pressure increases during later part of respiration. Following muscles are involve in inspiration. (a) Diaphragm : Principle muscles of inspiration. Its skeletal muscles attached to sternum, vertebral column and ribs. It is formed by radial muscles fibres. In relaxed condition it is dome shaped. Convex towards thoracic cavity and concave towards abdominal cavity. During inspiration it more...

(1) Skin : Many aquatic animals, such as Hydra and starfish, excrete ammonia into the surrounding water by diffusion through the body wall. In land animals, the skin is often not permeable to water. This is an adaptation to prevent loss of body's water. Mammalian skin retains a minor excretory role by way of its sudoriferous, or sweat glands and sebaceous, or oil glands. (i) Sweat gland : Sweat glands pass out sweat. The latter consists of water containing some inorganic salts (chiefly sodium chloride) and traces of urea and lactic acid. It also contains very small amounts of amino acids and glucose. (ii) Sebaceous glands : Oil glands pass out sebum that contains some lipids such as waxes, sterols, other hydrocarbons and fatty acids.  (2) Lungs : Carbon dioxide and water are the waste products formed in respiration. Lungs remove the\[C{{O}_{2}}\]and some water as vapour in the expired air. more...

(1) Pyelonephritis : It is an inflammation of renal pelvis, calyces and interstitial tissue (G.pyelos = trough, tub; nephros = kidney; it is = inflammation). It is due to local bacterial infection. Bacteria reach here via urethra and ureter. Inflammation affects the countercurrent mechanism, and the victim fails to concentrate urine. Symptoms of the disease include pain in the back, and frequent and painful urination. (2) Glomerulonephritis : It is the inflammation of glomeruli. It is caused by injury to the kidney, bacterial toxins, drug reaction, etc. Proteins and R.B.Cs pass into the filtrate. (3) Cystitis : It is the inflammation of urinary bladder (G.kystis = bladder, - it is = inflammation). It is caused by bacterial infection. Patient has frequent, painful urination, often with burning sensation. (4) Uremia : Uremia is the presence of an excessive amount of urea in the blood. It results from the decreased excretion of more...

(1) Protozoans : In protozoans like Amoeba and Paramecium carbon dioxide and ammonia are mostly excreted out by diffusion through general body surface. It is considered that the contractile vacuoles also play some role in the removal of excretory products.   (2) Sponges : In sponges, the nitrogenous metabolic waste (ammonia) leaves the body in the outgoing water current by diffusion. Most of the sponges are marine and have no problem of surplus water in their cells. A few sponges lie in hypotonic fresh water and have contractile vacuoles in most of their cells.     (3) Coelenterates : Hydra also lacks special excretory organs. The nitrogenous waste products like ammonia are removed through the general surface of the body by diffusion. Some nitrogenous waste products are also thrown along with indigestible matter through the mouth. more...