The process of hearing involves sound waves creating mechanical motions that cause fluid in the ear to move in waves and trigger nerve impulses that the brain interprets as sound. The outer ear functions to funnel sound waves. The vibrations from these waves reach the middle ear and move the tympanic membrane, often called the […]

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soft tissue repair

Soft tissue repair

Soft tissue organs in the body repair injury through a multi-step process that begins as platelets from torn vessels work to form a mesh-like clot that prevents blood loss. Inflammation in the area occurs as tissue repair begins in the damaged area. Mast cells release histamine that dilates blood vessels and increases blood flow to […]

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female sexs cells

Female sex cells

The ovaries produce secondary oocytes -the female sex cells. During fetal development stem cells, called oogonia, go through mitosis. Some of these cells develop into 46-chromosome primary oocytes. At the onset of female puberty tens of thousands of primary oocytes each form part of a primordial follicle in the ovaries. Between menarche and menopause, each […]

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involuntary reflexes

Involuntary reflexes

Somatic reflexes are automatic responses to stimuli that allow for fast reactions, before messages reach the brain. These reflex actions occur in a series of steps known as the reflex arc. First a sensory receptor detects a stimulus and a signal travels through afferent neurons towards the spinal cord. When the signal passes through the […]

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cardiac aupt

Cardiac output

With each contraction of the ventricles blood is pumped out of the heart. Stroke volume is the amount of blood a ventricle pumps out in one contraction. Cardiac output is the volume of blood that each ventricle ejects every minute. To find the cardiac output volume, multiply the number of heart beats in one minute […]

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heart conduction

Heart conduction

The heart’s conduction system regulates the electrical impulses that make the heart beat. An impulse begins in a bundle of nerve tissue called the sinoatrial (or SA) node. The impulse makes the atria contract, and blood empties into the ventricles. Next, the impulse travels to the atrioventricular (or AV) node. It passes through the Bundle […]

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urine creation ii

Urine creation I

Each kidney includes over a million blood-filtering units called nephrons. Blood enters the nephron through a capillary bed called a glomerulus. It is surrounded by a cup-like structure, the glomerular capsule, which is the beginning of the duct called the renal tubule. As blood flows through the glomerulus, blood pressure forces it against a specialized […]

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