urina creation

Urine creation II

Glomerular filtration produces a plasma-like filtrate containing waste, but also water and other substances the body needs. As the filtrate passes out of the glomerular capsule and through the renal tubule, substances like water, essential ions, glucose, amino acids, and proteins are reabsorbed into the body through cells along the tube wall. At the same […]

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funtion the skip

Function of the skin

The skin, nails, and hair of the integumentary system provide a barrier between the environment and tissues and organs within the body. The skin is the largest organ in the body. It absorbs nutrients, regulates internal body temperature, and eliminates waste. The epidermis is the outermost layer of skin that provides a barrier between the […]

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The process of seeing begins when light waves enter the front of the eye. Brightness and distinct colors are first interpreted by structures in the back of the eye, and then sent as stimulus signals that the brain interprets as vision. On the exterior of the eye is an area, called the cornea, that includes […]

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long bone formacion

Long bone formation

During embryonic development cells called chondroblasts begin secreting cartilage that develops in the shape of the skeleton’s long bones. The blue-ish, transparent, avascular tissue formed is called hyaline cartilage. As the cartilage grows, the chondroblasts in the interior calcify and die. Blood vessels penetrate the structure, and deliver osteoblasts. These cells lay down bone material. […]

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external respiration

External respiration

Inside the lungs, oxygen from the air is exchanged for waste carbon dioxide from the bloodstream. This process of external respiration takes place in hundreds of millions of microscopic sacs called alveoli. Oxygen from inhaled air diffuses from the alveoli into the pulmonary capillaries surrounding them, and is pumped through the bloodstream. Carbon dioxide from […]

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Pulmonary ventilation, or breathing, is induced by changes in the volume of the lungs and the air pressure within them. During normal inhalation the diaphragm and external intercostal muscles contract, and the ribcage elevates. As the volume of the lungs increases, air pressure in the lungs drops below atmospheric pressure, and air rushes in. During […]

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Specialized nervous system cells called neurons make this messaging possible. At one end of a neuron are dendrites that receive a messaging signal. In the neuron’s axon, a chain reaction moves the message to the synapse, where the signal is transferred. Before this process begins, the neuron is polarized with a net positive charge outside […]

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