Fundamentals of Anatomy and Physiology

296 Chapter 12

Career

Focus

These are careers that are available to individuals who are interested in the endo-crine

system.

● Nuclear medicine technologists are individuals who administer radioactive drugs,

known as radiopharmaceuticals, such as radioactive iodine for the treatment of a hy-

peractive thyroid gland. These radioactive drugs are also used for diagnostic imaging.^

● Endocrinologists are physicians whose specialty is the endocrine system and the

treatment of endocrine problems.^

● Diabetes dieticians are individuals trained as dieticians who specialize in nutri-tional

therapy, counseling, and the planning of balanced meals for patients with diabetes

mellitus.

Body Systems Working

Together to Maintain

Homeostasis:^
The Endocrine System

Integumentary System

●● Melanocyte production in the skin is caused by
melanocyte-stimulating hormone from the anterior
pituitary.^
●● Melanocytes produce melanin, causing a darker
pigmentation to skin for protection against the
harmful rays of the sun.^
●● Androgens activate sebaceous glands; estrogen
increases hydration of skin.

Skeletal System

●● Calcium concentrations in bone are controlled by the
hormones calcitonin and parathormone.^
●● Nerve cells of the hypothalamus function properly
due to proper calcium ion concentration.^
●● Bones protect the endocrine glands in the brain,
pelvis, and chest.

Muscular System

●● Hormones can cause increased heartbeat rates, which
help to increase the amount of blood carrying oxygen

and nutrients to exercising muscle cells.^
●● Growth hormone stimulates muscular development.

Nervous System

●● Nerve cells of the hypothalamus control the
secretions of the pituitary gland.

●● Through negative feedback, hormonal levels control

the secretions of the hypothalamus.

Cardiovascular System

●● The blood carries hormones to their target organs.

●● Heart rates and the diameter of blood vessels are

controlled by hormones.

Lymphatic System

●● Hormones stimulate the production of T lymphocytes.

●● Hormones are involved in the development of the

immune system in children.^

●● Lymph can be a route for hormone transport.

Digestive System

●● Glucose levels in the blood are controlled by

hormones.^

●● Excess glucose is stored in the liver as glycogen and

is made available to cells between meals by the

combined actions of insulin and glucagon.^

●● Hormones also affect digestive activities, such as

increased appetites during puberty caused by higher

rates of metabolism.

Respiratory System

●● Low levels of oxygen in the blood stimulate hor-monal

production of red blood cell formation in bone marrow.

●● Red blood cells transport oxygen from the lungs to

body cells and carbon dioxide waste from cells to the

lungs.^

●● Epinephrine increases breathing rates.