functions like a muscular pump that forces blood through the vessels
Heart
round and contain a substance called hemoglobin. Iron is an essential part of hemoglobin.
is just one of the systems that functions to remove waste from the body
Functions of the Endocrine System
• Maintaining the body’s internal environment
• Responding to internal and external challenges (stress, infection, trauma)
• Controlling the progress of growth and development
• Controlling reproductive and sexual functions
Carry oxygen rich blood away from the heart
Arteries
are colourless. Each has a particular function, and therefore has a little different structure. They protect the body against infection. They are also produced by the bone marrow, but they live only about 9 days.
White Blood Cells
Each about 10 cm (4 inches) long and shaped like lima beans. They lie just above the waist, under the rib cage and back muscles. They are made up of an elaborate system of coiled tubes called nephrons.
Kidneys
A system used to sense deviations from a set point, causing a response that moves the system back to the set point.
Negative feedback system
Carry un-oxygenated blood back to the heart
Veins
needed for blood clotting. They are also produced by the bone marrow. Their life span is about 4 days
Platelets
Tubes that carry the urine from the kidney down to the bladder. Each tube is approximately 30 cm (12 inches) long
Ureters
generates an electrical signal that causes the upper heart chambers (atria) to contract.
sinoatrial node
A short tube that leads from the opening of the bladder to the outside. The female urethra is approximately 4–6 cm (1½ to 2½ inches) long and the male urethra is approximately 19–24 cm (7½ to 9½ inches) long
Urethra