System Excretion in Humans (Part 2).

Assalamu’alaikum.

Happy Tuesday!

We will continue our discussion about yesterday about the excretory system in humans . tingga two organs of the four organs which we will discuss in this article .

3. skin

The skin is the outer portion of the body surface. Serves as a sensory tool, tool expenses, and the body's thermostat. Well, of course we are here to discuss the function of the skin as a means of spending, which is probably also a little later will connect as thermostat and body protection tool.

The structure of skin consists of three main layers, namely: the epidermis or epidermis, dermis cuticle, endo dermis contains fat reserves.

The epidermis : This is a brief of the epidermis is as follows . The epidermis is a stratified squamous epithelium , with beberpa layer visible . The main cells called keratinocytes . Which is the result of cell division in the deepest layer of the epidermis , which continues to grow to the outside , and then experienced the so-called terminal differentiation and forming cells of the surface layer ( stratum corneum ) .

The dermis is the layer of connective tissue just below the epidermis , and is the largest area of the skin . Overview of the dermis itself is like a woven fiber interlocking , consisting mostly of collagen fibers , and also by the elastin fibers . These fibers that make the dermis very strong and elastic , and is also very strong .

In this part of the skin structure important function is the dermis. Where in this section was the one that serves as excretion. For example: when friends do exercise, body temperature will rise, will make the blood vessels in the capillary expands, so will be more blood flow there. Thus making reddening of the skin. In addition, the sweat will be issued as a balancing of blood flow much earlier, then sweat it evaporated, well here's body temperature will drop.

The above process is also the lead after sweating we will feel thirsty.

4. Kidneys

In the human version, the kidney is the main excretory organ. Is the heaviest organ works to dispose of waste materials and regulate the balance of substances from the body.

Kidney shape itself as a big red beans. There are 2 kidneys or kidney pair, on the right and left upper abdomen of the human back. If split longitudinally, it will show the outside of the kidney (cortex) and the inside (the medulla, and the cavities of the kidney (pelvis).

Systems that work here is almost entirely carried out by the nephron. Nephron is the functional unit of the kidney. One kidney is composed of approximately one million nephrons.

Nephron consists of several parts, consisting of Bowman's capsule (which contained the glomerulus), proximal tubule, distal tubule and loop of Henle.

Some role in the renal excretion process are:

a. Secrete waste products, for example urea, uric acid, creatinine, keratin, and other substances that are toxic to our bodies.

b. Regulate blood plasma volume and the amount of water in the body.

c. Set the osmotic pressure in the blood, so that the body does not lose important salts in electrolyte balance.

d. PH acidity regulate levels in plasma or blood and body fluids. With secrete urine acidic or alkaline.

In the kidney, a process that is important for the excretion process of filtration, reabsorption, and augmentation so that later formed the urine and will be removed from the body.

In short we will discuss with the arrow diagram. Is as follows:

--> blood leading to glomerular filtration process --> undergo primary urine (urinary free blood cells and proteins) --> into the proximal tubule and Henle reabsorption --> occur (the re-absorption of glucose, amino acids, salts) --> secondary urine flow to the distal tubule --> augmentation process occurs addition of substances that are not needed --> addition of urea and certain substances -->  actual urine.

Finally we can finish from one system of the human body . Alhamdulillah . Exciting is not it? Of course we'll discuss further , regarding each of the organs which I have described in the excretory system and parts of two parts one .

Hopefully friends all could get benefit . DS apologize if there are errors in the writing . And if there is criticism or suggestions are very DS waiting in the comments field . Stay healthy , keep the spirit so that we can continue to learn about the science of this variety .

Wassalamu’alaikum.

Sources :

-Abdullah, Kirajuddin, dkk.2007.IPA TERPADU SMP dan MTs Jilid 3A untuk Kelas IX Semester 1.Jakarta:Erlangga

-Aryulina, Diah, dkk.2006.Biologi SMA dan MA untuk Kelas XI.Jakarta:Erlangga

-Djoko, Arisworo, dkk.2006.IPA Terpadu (Biologi, Kimia, Fisika).Jakarta:Grafindo Media Pratama

-Furqonita, Deswanty. 2007.Seri 3 BIOLOGI SMP kelas IX.Jakarta:Yudhistira

-Graham-Brown, Robin.2005.Dermatologi : Catat Kuliah.Jakarta:Erlangga