Anatomy and Physiology
ANATOMY AND PHYSIOLOGY 4
The body is made up of many organs. The organs are grouped accordingto their respective functions to form organ systems. The organs thatperform similar functions form the same organ system. Examples oforgan systems are the urinary system, the digestive system, and thebreathing system. All the organ systems then make up the whole bodywith each serving various roles.
The Digestive System
The digestive system is made up of organs that take part in thedigestion of food. The process of digestion involves a series ofprocesses that include ingestion, digestion, absorption, excretion,and secretion. The food is introduced into the body through themouth, and the process is known as ingestion. It is then chewed inthe mouth and rolled into many ball-like lumps through a processknown as mastication.
The food is then forced down into a tube-like structure called theesophagus through the larynx and down into the stomach. The processinvolves segmented contractions of the esophagus to produce wave-likemovements thus facilitating the movement of food. This process iscommonly known as swallowing. It is essential for the introduction offood into the stomach for further digestion.
The food is then taken to the duodenum where it is introduced tovarious digestive juices and enzymes. They help in breaking it downinto small pieces that can be absorbed into the body. Other partslike the pancreas and the gall bladder are used in the secretion ofthe digestive juices. The absorption of vitamins takes place in thestomach. There are two types of vitamins: fat soluble and watersoluble. When the food is completely broken down, it is passed intothe ileum for absorption of essential nutrients.
The ileum has many finger-like structures known as the villi andmicrovilli that increase the surface area for absorption. It is aboutthree meters long, and movement of food is slow to ensure that it hasample time for absorption. However, some waste products are producedduring digestion. They are excreted from the body through the anusand are referred to as feces.
The Urinary System
The urinary system consists of excretory organs like the urethra,ureters, kidneys and the bladder. The kidneys are the most importantorgans in this system. They exist as a pair in the body. The primaryfunction of the kidneys is to regulate the volume of fluids and thecomposition of chemicals in the body. This facilitates themaintenance of homeostasis in the body of an organism.
The kidney is involved in two main processes to accomplish its role.They include glomerular filtration and tubular transfer of water andsolutes. A mechanical process takes place to produce a plasmaultrafiltrate in the glomeruli. The variations in constriction of theafferent and efferent arterioles help in the regulation of glomerularfiltration.
The glomerular filtration rate is high thus producing many liters,which can add up to one hundred and fifty. However, daily amounts ofurine consist of up to one and a half liters meaning that many moreliters are reabsorbed into the body as they pass through the tubularsystem. Minerals such as sodium are absorbed together with water. Theabsorption of large amounts of potassium minerals may lead tohyperkalemia and metabolic acidosis. A decrease in absorption ofpotassium may also result in hypokalemia, which may causearrhythmias. It is, therefore, important to regulate the rate ofreabsorption.
It is appropriate to conclude that the both the urinary and thedigestive system are vital organ systems in the body. The digestivesystem provides essential nutrients to the body and excretion of thewaste products. The urinary system facilitates the excretion of urineand the reabsorption of water into the body. It is, therefore,important to keep their functionalities optimum at all times.
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