Thursday, September 14, 2017

Thymus

Thymus of Human Organ


The thymus is a vascular organ of the lymphatic system situated just behind the breastbone. The human thymus continuous to grow for about a year after birth, reaching a weight of about 42 g; this size is maintained until puberty. After puberty the lymphatic tissue is replaced by fat, but the thymus remains functional throughout life.


Thymus of human organ and the function of thymus
Thymus



The main function of thymus is to process lymphocytes received from the blood producing bone marrow and fetal liver. These cells proliferate and differentiate in the thymus into thymic lymphoid cells called T cells, each one programmed for the number of antigens to which it will react. In humans the cellular immune system requires the presence of the thymus at birth; this system allows the body to recognize foreign, that is “non self” tissue and to attack malignant cells, viral infection, fungal infection, and some bacteria. Little is known of the factors and processes of thymic function. The importance of the thymus to the human immune system, however, is readily demonstrated in some patients with congenital thymic deficiency states by the restoration of immunological responsiveness after fetal thymus graft.

The thymus gland is an organ of the lymphatic system, which protect the body against infection. Located behind the sternum, near the heath and lungs, it is well supplied with blood vessel. Its two main lobes are each subdivided into numerous lobules; a network of delicate connective tissue holds the lobes together. Within each lobule are two zones of tissue, inner zones called the cortex and an outer zone called the medulla. The cortex is composed of lymphocytes, while blood cells that produced antibodies and attack bacteria; this lymphocytes are packed into a fiber structure called a reticulum. The medulla has a more cellular reticulum and contains thymic corpuscles, which are concentric clusters of epithelial cells enclosing a core of granular cells. The function of these corpuscles is not yet understood. The thymus is most active during fetal and childhood growth. Its main function appearing to be the production of lymphocytes and the destruction of defective lymphocytes. The thymus may also secrete a hormone that influence the response of lymphocytes for foreign tissue. After puberty the thymus slowly degenerates.

Thyroid Gland

Thyroid Gland

Thyroid Gland and Endocrine Gland



The thyroid, and endocrine gland, synthesizes stores and secretes two hormones, thyroxine or tetraiodothyronine (T4), and triiodothyronine (T3), that are chemically related and important to human growth and metabolism. Located below the larynx (voice box), the thyroid’s two lobes occurs on either side of the wind-pipe, connected by an isthmus (band of tissue). The gland is composed of many hollow sacs (follicles) filled with colloid (a gelatin material), which contains thyroglobulin, the storage form of the hormones. Essential to the synthesis of the hormones is inorganic iodide, which diffuses from citonin of calcitonin, acts against excessive levels of calcium in the blood and against the effects of parathyroid hormone on bone resorption.

Thyroid hormone secretion is controlled by thyroid stimulating hormone (TSH), or thyrotropin, from the anterior pituitary. In turn the resultant increase in the level of thyroid hormones in the blood serves to signal the pituitary to stop releasing the thyrotropin. This haemostatic mechanism keeps the level of thyroid hormones in the circulatory system within a constant range. A lack of thyroid function in infants causes cretinism, whereas a loss or low levels of the thyroid hormones later in life result in hypothyroidism, or myxedema and possibly Goiter. Over production of the hormones, or hyperthyroidism, also may result in goiter.

Thyroid Gland Function and Lab Test


A thyroid function test measures the efficiency of thyroxine and triiodothyronine production by the thyroid gland. These two thyroid hormones which contain iodine, regulate body metabolism. If the hormones are deficient, as in the condition called myxedema, metabolism is slowed down. If they are in excess, as in exophthalmic Goiter, metabolism is accelerated. The oldest method of measuring thyroid function is the determination of the basal metabolic rate, or BMR. The relationship of the BMR to thyroid hormone levels, however, is indirect and inexact. The BMR test has thus been superseded by such test as the radiation method, which measures the rate at which injected radioactive iodine become concentrated in the thyroid gland. This rate is directly related to the rate of thyroid hormone synthesis. Other test include measurement of the competitive protein binding of thyroxine, serum thyroxine, the level of thyroid stimulating hormone (TSH), free thyroxine in blood and urine, and triiodothyronine estimations.

Thursday, September 7, 2017

Kidney Structure

Human Kidney and Function of Kidney


Kidney is a human organ  like kidney beans shaped. In humans, kidney size, which is a length of 10 to 12 cm, width 5-6 cm, and thick, 3-4 cm, weighing about 140 grams. In cross kidneys, visible parts are different. The sections are from outside into the cortex, medulla, and pelvis. In the renal cortex and medulla there are about 1 million nephrons. Nephron is the structural and functional unit of the smallest of the kidney. Nephron serves as a screening tool.


Human Organ

Nephron is shaped like a large worm-headed eagle with a body like the winding. At the head there is a fine mesh that can only be bypassed by certain substances. Blood cells and blood proteins can not pass through this filter because it was bigger. The composition of the nephron consists of the following sections.

1) Malpighian Body, which includes Bowman's capsule and glomerulus.
2) convoluted tubules including proximal tubules, Henle, and distal tubules.

Some tubular-shaped winding, and some straight. The first section of the tubular winding, called the proximal tubule. After that there is a loop of Henle. Tubule weaved again as the second bend of the distal tubule called then concatenated with the tubule reservoir across the cortex and medulla. Each nephron consists of malpighi body. In this malpighi there is a section called Bowman's capsule-shaped bowl and in it there is glomerus. In the glomerular capillaries have blood.

Kidney Parts

Monday, November 3, 2014

Animals Nose

In vertebrates nose have function to expel air for respiration in conjunction with mouth. As like human, behind nose are olfactory mucosa and sinuses. Behind the nasal cavity, air will passes through pharynx, shared with digestive system, then air into the rest of respiratory system.

As like in human vertebrates’ nose also have similar function like inhale air from the atmosphere and take oxygen after passes the lung then release carbon dioxide. In vertebrates nose also have inner hairs whose functions to stop unwanted particles from entering the lungs.

In wet nose like dogs is useful for the perception of direction. Sensitive to cold receptors in the skin detect the place where the nose is cooled the most and this is the direction a particular smell that the animal just picked up comes from. The sensitive of smell on Dog nose is better than other normal animals.

Different in reptiles, nose have function to sense of heat that can predict the distance of other animal. The nasal chamber is generally larger, with the choanae being located much further back in the roof of the mouth. In crocodilians, the chamber is exceptionally long, helping the animal to breathe while partially submerged. The reptilian nasal chamber is divided into three parts; anterior vestibule, main olfactory chamber and posterior nasopharynx.

Sunday, October 27, 2013

Bladder Cancer

Bladder cancer is a type of cancer that develops in the bladder; a balloon shape organ located in the pelvis that deviate urine. Most of these cancers start in the cells that line inside of the bladder.

This cancer usually attacks adults, although all age groups have the same opportunities. Generally, the cancer is diagnosed at an early stage of development, where the cancer is still treatable.

SYMPTOMS
Bladder cancer has the following symptoms:
  • There is blood in the urine (hematuria) or urine may be normal, but blood can be detected by microscopic examination .
  • Frequent urination
  • Pain during urination
  • Infection of the urinary tract
  • Pain in the stomach area
  • Backache
Causes; Risk Factors

It is unclear what causes bladder cancer. Bladder cancer has been linked to smoking, parasitic infections, radiation and exposed to chemical substances. Bladder cancer occurs due to mutations in cells. This mutation causes cells to grow out of control and then live while the other cells die.

Risk factors
Some factors that increase the risk of bladder cancer include:
  • Increasing age
  • white skinned
  • Smoking
  • Exposure to certain chemicals ( eg arsenic )
  • The use of anti-cancer drug cyclophosphamide ( Cytoxan ) for previous cancer
  • Chronic Bladder Inflammation
  • Personal notes or family with cance
Prevention

Although there is no guarantee to prevent bladder cancer , but you can take steps to reduce your risk of developing bladder cancer . Among others:
  • Do not smoke
  • Beware of chemicals in your environment
  • Drink enough water so that toxins can be wasted along with the urine
  • Choose fruit or vegetable foodstuffs