Excretion System in Humans

Excretion is the process of removing metabolic waste in the form of liquid and gaseous substances. The remaining waste substances are in the form of urine (kidney), sweat (skin), bile (liver), and CO 2 (lungs). These substances must be removed from the body because if not removed will interfere with even poisoning the body. Besides excretion, there are also defecations and secretions. Defecation is the removal of waste products from the digestive process in the form of feces (feces) through the anus. While secretions are expenditures by cells and glands in the form of sap and are still used by the body for other processes such as enzymes and hormones.

Kidney

Humans have a pair of kidneys located in the right and left abdominal cavity vertebrae. The location of the left kidney is higher than the right kidney. That's because on the right kidney there is a large liver. Kidney shapes such as purplish red bean seeds with a length of about 10 cm and a weight of about 200 grams. Kidney is wrapped by a kind of thin membrane called 'capsule'.
Kidney function:

• Filtering metabolic waste from the blood released in the form of urine.
• Maintaining and regulating water balance in the body.
• Maintaining osmotic pressure by regulating the concentration of salt in the body.
• Maintaining a balance of acid and base levels by removing excess acid or base in the urine.
• Excreting metabolic remnants such as urea, creatinine, and ammonia through urine.

Renal Parts:
 

1. Cortex (kidney skin), there are millions of nephrons which consist of malphigi bodies. The malphigi body is composed of the glomerulus enveloped by the Bowman capsule and tubules (channels) consisting of proximal tubule, distal tubule and tubular collections.
2. Medulla (kidney marrow), consisting of several cone-shaped bodies (pyramids). Here there is the henle arch which connects the proximal tubule and the distal tubule.
3. The renal cavity (pelvis), is a place where the tubules burst, which is a temporary reservoir of urine that will flow into the bladder through the ureter and expelled from the body through the urethra.

The process of forming urine in the form of a scheme:

Blood from the aorta to the glomerulus (filtration or filtering) protein remains in the blood vessels and formed a primary urine containing water, salt, amino acids, glucose and urea >>> proximal tubule consortium (reabsorption or re-absorption) absorbs glucose, salt, water , and amino acids. Formed secondary urine containing urea >>> distal contour tubules (augmentation or release of substances) release substances that are not useful or excessive into the urine and form actual urine >>> tubular collections >>> renal cavity >>> ureter >> > bladder >>> urethra >>> urine exits the body.
(For more details, see the full picture in parts and anatomy of the kidney)
So, the formation of urine is divided into 3 stages, namely filtration, reabsorption (re-absorption), and augmentation (removal of substances).
Substances contained in urine:

• Water. Approximately 95%.
• Urea, uric acid, and ammonia and is a residual disassembly of proteins.
• Bile which gives the urine yellow color.
• Salt.
• Other toxic or excessive substances.

Factors that influence the amount of urine that comes out:

1. The amount of water you drink.
2. The amount of salt that must be removed from the blood for osmosis is balanced.
3. Effect of antidiuretic hormone (ADH) or vasopressin hormone. That is the hormone that regulates water levels in the blood.
4. Climate / season / weather. When the rainy season (cold) excessive urine production, when the dry season (hot) urine production decreases.
5. Stimulus or nerves.

Disorders and abnormalities in the kidney:

1. Uremia	accumulation of urea in the blood resulting in poisoning.
2. Albuminuria	urine contains albumin (protein) caused by damage to the glomerulus.
3. Diabetes insipidus	vasopressin deficiency disease or antidiuretic hormone (ADH) which results in loss of the ability to reabsorb fluid. As a result, sufferers can release abundant urine reaching 20 liters.
4. Diabetes mellitus	glucose is present in the urine. Occurs because of decreased insulin hormone produced by the pancreas.
5. Nephritis	disorders of the kidneys due to streptococcal bacterial infection so that the protein enters the urine.
6. Kidney stones	the presence of calcium salt deposits in the bladder
7. Kidney failure	the kidneys cannot function properly so they must be helped by dialysis or a kidney transplant.
8. Hematuria	urine contains blood because of damage to the glomerulus.

Skin

The skin is one of the excretion tools. Because the skin sweat. Sweat comes out through the pores of the skin. Sweat contains water and mineral salts.
Skin function:

• A means of excretion (excretion) in the form of sweat.
• Protecting the body from physical disorders (light, pressure and temperature), biological disorders (fungi) and chemical disorders.
• Regulate body temperature.
• The place of making vitamin D from provitamin D with the help of sunlight.
• A place to store excess fat.
• As a sense of touch.

Leather Parts:

1. Epidermis (epidermis layer)

Is the outer portion that is very thin. This section consists of two layers, namely:
a. The horn / stratum corneum layer

• The outermost layer and composed of dead cells.
• Easy to peel off.
• Does not have blood vessels and nerves so it does not hurt and does not bleed when this layer is peeling.

b. Malpighi coating

• Composed of living cells.
• There are pigments that give skin tone and protect from the sun.
• There are nerve endings.

2. Dermis (hides of skin)

The dermis layer is thicker than the epidermis layer. In this layer there are the following parts:

• Blood vessels to transport nutrients to the hair.
• Sweat glands produce sweat that is released through the pores of the skin.
• Nerve endings. Consisting of pacini corpuscles (pressure receptors), meissner's corpuscles (touch / receptor receptors), ruffini corpuscles (heat receptors), pain receptors, and krause corpuscles (cold receptors).
• Oil glands. Produces oils that function to oil the hair and skin so they don't dry out.
• Hair bag is where the root of the hair is embedded.

3. Subcutaneous tissue (subcutaneous)

In this tissue there is fat that functions to hold body heat and protect the inner body from collisions.
(For more details, see the full picture in the parts and anatomy of the skin)
Factors that trigger sweat:

1. Increased body activity
2. increase in ambient temperature
3. emotional shock
4. nerves

Skin disorders:

 

1. Acne is a disorder of the oil glands that are commonly experienced by teenagers.
2. Scabies or scabies is a skin disease due to mites ( Sarcoptes scabies ).
3. Cutaneous pruvitus is a skin disease with symptoms of itching arising triggered by irritation of peripheral sensory nerves. 
4. Eczema or allergy is a skin disease due to infection or irritation from outside materials that are eaten or touch the skin.
5. Gangrene is a skin disorder caused by the death of body tissue cells. This is caused by poor blood supply in certain parts, one of which is due to pressure on certain blood vessels (such as bandages that are too tight).

Lungs

 

The lungs are also a means of excretion. Because the lungs emit CO 2 gas and water vapor. Lung function: The lungs function as an exchange of oxygen and carbon dioxide which is not needed by the body. In addition there are many more functions of the lungs including the body's acid-base balance guard. when acidosis occurs, the body will compensate by removing a lot of acidic carbon dioxide out of the body. Disorders of the lungs: 

• Asthma or shortness of breath. Caused by allergic to foreign objects that enter the nose.
• Lung cancer. Caused by smoking or inhaling too much asbestos dust, chromium, petroleum products, and ionizing radiation that affect the exchange of bases in the lungs.
• Emphysema is an alveolar swelling that causes the respiratory tract to narrow.

Heart

The liver is one of the excretion tools because the liver secretes urea and ammonia outside the body. The liver is located in the right abdominal cavity below the diaphragm. Dark brownish red heart weighing around 2 kg.
Liver function:

• Store glycogen (muscle sugar) which is the result of conversion of glucose due to the hormone insulin.
• Neutralize poison.
• Form prothrombin (for blood clotting).
• The place to convert provitamin A to vitamin A.
• The site of formation of urea and ammonia that comes from the breakdown of damaged proteins which are then removed from the body through urine.
• Place of formation of red blood cells in the fetus.
• As an excretion organ which is tasked with overhauling erythrocytes (red blood cells).

Disorders of the liver:

1. Wilson disease is a hereditary disease with excessive levels of copper in the body resulting in impaired liver function.
2. Hepatitis is inflammation or swelling of the liver.
3. Cirrhosis is a chronic liver disease and causes strokes in the liver so that the liver becomes dysfunctional. 

How? Have understood with the excretion system that may be useful