Medical Lad

Internal structure of the kidneys seen on a dissected specimen INTRODUCTION The closely packed structure and numerous functions of the kidney illustrate the beautiful workmanship of our creator. It not only applies to the kidney but to each and every part of our body. Synonyms The kidney are also called renes from which we have the derivative renal and nephros from which we have the terms nephron, nephritis, etc Definition Kidneys are a pair of excretory organs located on the posterior abdominal wall, one on each side of the vertebral column, behind the peritoneum. They remove waste products of metabolism and excess of water and salts from the blood, and maintain its pH. Location Location of the kidneys The kidneys occupy the epigastric, hypochondriac. lumbar and umbilical regions. Vertically they extend from the upper border of twelfth thoracic vertebra to the center of the body of third lumbar vertebra. The right kidney is slight

INTRODUCTION Abdominal cavity is the largest cavity. It encloses the peritoneal cavity between its parietal and visceral layers. Parietal layer clings to the wall of parieties while visceral layer is intimately adherent to viscera concerned. So their vascular supply and nerve supply are same as the parieties and viscera respectively. There are very lengthy organs in the abdominal cavity. These had to be disciplined with limited movements for proper functioning of the gut in particular and the body in general. Infections involving the parietal peritoneum impart protective "board-like rigidity" to the abdominal wall. Referred pain from the viscera to a dístant area is due to somatic and sympathetic nerves reaching the same spinal segment. NINE REGIONS OF ABDOMEN  For the purpose of describing the location of viscera, the abdomen is divided into nine regions by four imaginary planes, two horizontal and two vertical. The horizontal planes are the transpyloric and transtuber- cul

Ureter Introduction The ureters are a pair of narrow, thick-walled muscular tubes which convey urine from the kidneys to the urinary bladder.            They lie deep to the peritoneum, closely applied to the posterior abdominal wall in the upper part, and to the lateral pelvic wall in the lower part. DIMENSIONS  Each ureter is about 25 cm (10 inches) long, of which the upper half (5 inches) lies in the abdomen, and the lower half (5 inches) in the pelvis. It measures about 3 mm in diameter, but it is slightly constricted at five places.  Course General course of the ureter in the pelvis The ureter begins within the renal sinus as a funnel- shaped dilatation, called the renal pelvis. The pelvis issues from the hilus of the kidney, descends along its medial margin, or partly behind it. Gradually it narrows till the lower end of the kidney where it becomes the ureter proper.        The ureter passes downwards and slightly medially on the tips of trans

Different cell junctions  DEFINITION Cell junction is the connection between neighboring cells or the contact between the cell and extracellular matrix. It is also called membrane junction. Connection between two cells is called intercellular junction. Tight junction, gap junction, adherence junc- tion and desmosome are intercellular junctions. Contact between the cell and extracellular matrix are focal adherence and hemidesmosome. CLASSIFICATION   Cell junctions are classified into three types:  1. Occluding junctions. 2. Communicating junctions.  3. Anchoring junctions. OCCLUDING JUNCTIONS  Cell junctions which prevent intercellular exchange of substances are called occluding junctions, i.e. these junctions prevent the movement of ions and molecules from one cell to another cell. Tight junctions belong to this category.   TIGHT JUNCTION  Tight junction is the intercellular occluding junction that prevents the passage of large molecules. It

Large Intestine Features The large intestine extends from the ileocaecal junction to the anus. It is about blind 1.5 m long, and is divided into the caecum (Latin blind pouch), the ascending colon, right colic flexure, the transverse colon, left colic flexure, the descending colon, the sigmoid colon, the rectum and the anal canal. In the angle between the caecum and the terminal part of the ileum, there is a narrow diverticulum called the vermiform appendix (Latin attachment).  The general structure of large intestine is considered first followed by its parts one by one. The structure of the large intestine is adapted for storage of matter reaching it from the small intestines, and for absorption of fluid and solutes from it. The epithelium is absorptive (columnar), but villi are absent. Adequate lubrication for passage of its contents is provided by numerous goblet cells scattered in the crypts as well as on the surface of the mucous membrane. The presence of numerous solitar

Organelles Of Cell CYTOPLASM  Cytoplasm of the cell is the jelly-like material formed by 80% of water. It contains a clear liquid portion called cytosol and various particles of different shape and size. These particles are proteins, carbohydrates, lpids or electrolytes in nature. Cytoplasm also contains many organelles with distinct structure and function.  Cytoplasm is made up of two zones: 1. Ectoplasm: Peripheral part of cytoplasm, situated just beneath the cell membrane. 2. Endoplasm: Inner part of cytoplasm, interposed be- tween the ectoplasm and nucleus.  ORGANELLES IN CYTOPLASM  Cytoplasmic organelles are the cellular structures embed- ded in the cytoplasm. Organelles are considered as small organs of the cell. In Latin the word organelle means small organ. Some organelles are bound by limiting membrane and others do not have limiting membrane. Each organelle is having a definite structure and specific functions. ORGANELLES WITH LIMITING MEMBRAN