a brief summary...
The human body has multiple ways of maintaining homeostasis, the most prominent of these is the disposal of wastes through the excretory system. Every living thing creates useless and sometimes toxic byproduct through necessary processes. The excretory system filters these wastes out of the blood and sends them to the kidneys to be processed and disposed of. Wastes are also disposed of through the skin. Without the excretory system, life would not be able to maintain homeostasis and survive.
The Kidney is the most important of the excretory organs. They remove waste products from the blood, maintain blood pH, and regulate the water content of the blood (along with blood volume). The Kidneys are located on either side of the spinal column. Dirty blood comes in from the Renal artery. The blood is filtered. Clean blood goes back into circulation through the Renal Vein. A tube called the ureter leaves the kidney and carries the processed waste to the urinary bladder to be disposed of. The inner part of the Kidney is called the Renal Medulla. The outer part is called the Renal Cortex. The functional unit of a kidney is the nephron. It is the unit that does the actual processing. Blood will enter the nephron through the arteriole. It will go through the nephron being filtered. The wastes will be emptied into the collecting duct. The clean blood will leave through the venule. Filtering the blood is done by two processes: Filtration and Reabsorption. |
Filtration takes place in the part of the nephron called the glomerulus, which is enclosed in a capsule called the Bowman’s Capsule. Unwanted things that are small enough to fit through the capillary walls will be expelled from the blood. These things are urea, glucose, water, salts, and amino acids. These ingredients are collectively called the filtrate. The actual blood is too large to fit through the capillary walls, so it remains.
Some of the wastes and 99% of the water filtered by the kidneys make it back into the blood through reabsorption. The material that remains after reabsorption is called urine. It is emptied into the urinary bladder and eliminated. Another aspect of the Excretory System is the skin, also called the Integumentary System. The skin serves as a barrier against infection and injury, regualtes body temperature, but it also removes waste products. The outermost layer of the skin is the epidermis. The outside is made of dead cells, the inside of living ones. The epidermis contains melanocytes, which produce melanin. The distribution of melanin across the skin determines skin color. The Dermis is the inner layer of the skin. It has sweat and sebaceous glands. They produce sweat and oil, respectively. The skin is covered with tiny holes called hair follicles, out of which grows hair. Hair follicles are tubelike holes that house hairs and extend down into the Dermis. |
TERMS TO KNOW ;
· Epidermis- the outer layer of the skin
· Keratin- a protein that waterproofs and protects the cells and tissues underneath
· Melanin- protects deeper cells from the damaging effects of ultraviolet rays of sunlight
· Dermis- the thicker second layer of skin below the epidermis
· Hair Follicles- hair cells that grow out of holes in the dermis
· Sebaceous glands- glands in the skin that produce oil
· Kidneys- two bean-shaped organs that filter out wastes, water, and salt from the blood
· Urea- nitrogenous waste product produced as a byproduct to protein synthethis
-The excretory system helps maintain homeostasis within an organism and also prevents damage from happening to the organism.The excretory system removes any excess and unwanted materials.
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-The excretory is responsible for the exaltation of bodily wastes produced by metabolism such as liquid and gaseous wastes, urine, sweat, and exhalation.
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