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The outer layer of the epidermis is made up of dead cells The inner layer of the epidermis is made up of living cells that undergo rapid cell division and also make keratin, a tough, fibrous protein The epidermis also contains melanocytes: cells that produce melanin, a dark brown pigment
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The outer layer of the epidermis is made up of dead cells • The inner layer of the epidermis is made up of living cells that undergo rapid cell division and also make keratin, a tough, fibrous protein • The epidermis also contains melanocytes: cells that produce melanin, a dark brown pigment • There are no blood vessels in the epidermis Hair Sweat Pore Epidermis Nerve Dermis Oil gland Hair follicle Sweat gland Fat tissue Dermis: contains collagen fibers, blood vessels, nerve endings, glands (sweat and oil) and hair follicles Helps regulate body temperature: Hot: blood vessel dilate, produce sweat Cold: blood vessel constrict
Capillaries Renal Cortex Bowman’s capsule Glomerulus Renal artery Renal Medulla Renal vein Collecting tubule Ureter Vein Artery Loop of Henle To ureter
Reabsorption: • As the filtrate flows through the renal tubule, most of the water and nutrients are reabsorbed into the blood • The concentrated fluid that remains is called urine • Filtration: • Most filtration occurs in the glomerulus • Blood pressure forces water, salt, glucose, amino acids and urea into Bowman’s capsule • Proteins and blood cells are too large to cross • The fluid that enters the renal tubule is called the filtrate Secretion: - Substances such as hydrogen ions are transferred from the blood to the filtrat