cardiovascular system

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Human Body Organ Systems
Nutrition and Cardiovascular Diseases Editor: The lack of a nucleus means that red blood cells contain no DNA and are not able to repair themselves once damaged. Inhalation breathing in is usually an active movement. Vegetables and fruits supply a rich amount of antioxidants and other nutrients that can support the ability of your immune system to protect the body from disease, infections, and toxins, which are associated with cancer. To avoid these dangers, it is best to consume mushrooms that have been cultivated under appropriate conditions.

Health benefits of mushrooms

Digestive System

The odour or smell of any material or object is a result of minute quantities of special chemicals that are detected by the olfactory membrane that in turn sends a signal via the olfactory nerve to the brain where it will be recognised for what it is. Their action is to supplement the action of the kidneys by reducing the electrolyte content of body fluids, especially when the level is higher than the kidneys can handle electrolyte — common chemical salts e.

The oropharynx consists of the mouth and the pharynx that is located immediately behind it. The palate is part hard and part soft. The choanal opening from the nasal cavity is the cleft in the palate.

The pharynx begins between the choanal opening and the common opening for the auditory tubes and extends to the rear to include that section of the oral cavity carrying the base of the tongue, the tip of which is located in the mouth. Behind the base of the tongue is found the rima glottidis or opening into the larynx, which is sometimes called the cranial larynx.

This opening is located in a conspicuous mound called the laryngeal prominence. The opening into the larynx is a median slit that is supported on each side by the arytenoid cartilages. These are special cartilages with a shape resembling the mouth of a jug or pitcher. It varies in length from approximately 8. During gasping while the bird is in a state of respiratory distress it can open to a width of 7 to 9 mm. There are no vocal cords, epiglottis and thyroid cartilages that are normally found in mammals.

This organ is a long tube with the function of moving the respiratory gases from the upper respiratory system to the organs of respiration — the lungs and air sacs or from the air sacs and lungs to the upper respiratory organs. The trachea in medium sized adults measures between 15 and 18 centimetres. It is held open permanently by to cartilaginous rings each one complete and lapping its neighbour. This arrangement prevents the trachea from collapsing or compressing but allows elongation and flexion.

Most of the muscles in the region are involved in the movement of the head and neck and are not associated with respiration. Numerous mucous secreting glands are also found in the tracheal lining. The syrinx is the vocal organ of the fowl. It is located at the caudal end of the trachea and is suspended within the clavicular air sac. At rest, it is compressed laterally at the sides. It consists of the pessulus, a wedge shaped cartilage located where the trachea divides into two to form the two bronchi plus the last four specialised cartilaginous rings at the bottom of the trachea.

Below this section there are thin, flexible syringeal cartilages which are fused at one end to the pessulus but which are free at the other.

These are sometimes called the intermediate cartilages or syringeal ears. At the syrinx the trachea forms two bronchi that then enter the lungs. The walls of the syrinx are two thin, vibrating membranes called the tympanic membranes. The bird makes sound by causing these membranes to vibrate.

The tension of these membranes is controlled by muscles and the tension governs the sound produced. It is interesting to note that the combined cross sectional area of the bronchi is more than double that of the caudal end of the trachea from which they arise 30 mm2 v This means that there is a significant reduction of air pressure and resistance to airflow in the bronchi than in the trachea. The cartilaginous rings of the bronchi extend from the syrinx to where the bronchi enter the lungs.

Ciliated epithelium with numerous mucous glands lines the primary bronchi. On entering the lungs, the primary bronchi divide to form four series of secondary bronchi and these, in turn, divide again to form numerous anastomising tertiary bronchi or parabronchi.

The secondary and tertiary bronchi are lined with squamous epithelium and not the ciliated epithelium of the primary bronchi. The tertiary bronchi are arranged in layers. They are not blind ending, but join others that in turn lead back to the secondary and primary bronchi. Ultimately, the bronchial system is continuous.

Leading off from the bronchi in the lungs are a large number of extremely small air capillaries ducts that are interlocked with the capillaries of the lung circulatory system.

The avian lung is a flattened structure that occupies the roof of the cranial or head end of the coelom. While on a body weight basis the volume of the avian lung is only one tenth of that of mammals of equal body size, it weighs significantly more 1. This indicates that the avian lung is very much denser than that of mammals. The surfaces adjacent to the ribs are very indented and the ribs lie within the grooves that are formed such that approximately one third of the lungs lie between the ribs.

The bright pink lungs are formed at the end of the bronchi and their terminal structures are called the air vesicles or sacs. Unlike other species, the avian lungs have very little elasticity. The air sacs are very thin walled extensions of the bronchi that could be likened to balloons.

This storage capacity allows the body to eat only a few times each day and to ingest more food than it can process at one time. In the course of a day, the digestive system secretes around 7 liters of fluids. These fluids include saliva, mucus, hydrochloric acid, enzymes, and bile. Saliva moistens dry food and contains salivary amylase, a digestive enzyme that begins the digestion of carbohydrates.

Mucus serves as a protective barrier and lubricant inside of the GI tract. Hydrochloric acid helps to digest food chemically and protects the body by killing bacteria present in our food. Enzymes are like tiny biochemical machines that disassemble large macromolecules like proteins, carbohydrates, and lipids into their smaller components.

Finally, bile is used to emulsify large masses of lipids into tiny globules for easy digestion. Digestion is the process of turning large pieces of food into its component chemicals. Mechanical digestion is the physical breakdown of large pieces of food into smaller pieces. This mode of digestion begins with the chewing of food by the teeth and is continued through the muscular mixing of food by the stomach and intestines.

Bile produced by the liver is also used to mechanically break fats into smaller globules. While food is being mechanically digested it is also being chemically digested as larger and more complex molecules are being broken down into smaller molecules that are easier to absorb.

Chemical digestion begins in the mouth with salivary amylase in saliva splitting complex carbohydrates into simple carbohydrates. The enzymes and acid in the stomach continue chemical digestion, but the bulk of chemical digestion takes place in the small intestine thanks to the action of the pancreas.

The pancreas secretes an incredibly strong digestive cocktail known as pancreatic juice, which is capable of digesting lipids, carbohydrates, proteins and nucleic acids. By the time food has left the duodenum , it has been reduced to its chemical building blocks—fatty acids, amino acids, monosaccharides, and nucleotides. Once food has been reduced to its building blocks, it is ready for the body to absorb. Absorption begins in the stomach with simple molecules like water and alcohol being absorbed directly into the bloodstream.

Most absorption takes place in the walls of the small intestine, which are densely folded to maximize the surface area in contact with digested food. Small blood and lymphatic vessels in the intestinal wall pick up the molecules and carry them to the rest of the body.

The large intestine is also involved in the absorption of water and vitamins B and K before feces leave the body. The final function of the digestive system is the excretion of waste in a process known as defecation. From Wikipedia, the free encyclopedia. The movement of oxygen from the outside environment to the cells within tissues, and the removal of carbon dioxide. This section is in a list format that may be better presented using prose. You can help by converting this section to prose, if appropriate.

Editing help is available. Retrieved from " https: Articles with short description Articles needing cleanup from February All pages needing cleanup Articles with sections that need to be turned into prose from February

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