The endocrine system: Endocrine glands and hormones

Where is the pineal gland located

Small, cone shaped body in the posterior epithalamus

What hormone does the pineal gland secrete, and what does it do

Melatonin; helps regulate the sleep wake cycle

Describe the thyroid glands shape and location

Butterfly-shaped; right and left lobes connected by a midline isthmus in the anterior neck

What does calcitonin do

Lowers blood calcium by inhibiting osteoclast activity and promoting calcium deposition in bones

What does thyroxine do

Increases metabolic rate (BMR) and supports normal growth and development

What causes hypothyroidism, and what are its symptoms

Causes: thyroid failure of iodine deficiency

Symptoms: low BMR, weight gain, lethargy

What is a goiter? What is congenital iodine deficiency syndrome?

Goiter: enlarged thyroid

Congenital iodine deficiency: Inadequate maternal/infant iodine or thyroid hormone, causing slowed growth and intellectual disability

What is Graves disease

An autoimmune disease causing thyroid hormone hyper secretion

What are symptoms of graves disease

• Agitation

• Nervousness

• Bulging eyes

• Goiter

Where are the parathyroid glands located

Usually four small glands on the posterior surface of the thyroid gland

What does parathyroid hormone (PTH) do

Raises blood calcium by stimulating calcium release from bones and increasing calcium reabsorption in kidneys and absorption in intestines

How PTH and calcitonin work together

They are antagonistic: PTH raises blood calcium; calcitonin lowers it. Together they maintain calcium homeostasis

Where is thymus located, and how does it size change with age

Just above the heart and deep to the sternum. Larger in infants and children then adults

What does the thymus secrete, and what is it’s function

Thymosins; support development of mature T cells for immune function

Where are the adrenal glands located, and what are their two regions

Paired glands on the superior borders of the kidneys; outer cortex and inner medulla

What are the three adrenal cortex layers and their hormones

Superficial to deep: mineralocorticoids (aldosterone), glucocorticoids (cortisol), and gonadocorticoids (androgens)

What does aldosterone do

Increases sodium and water reabsorption by the kidneys, helping regulate blood volume and blood pressure

What does cortisol do

Helps regulate metabolism and the stress response; increases blood glucose and has anti-inflammatory effects

What do adrenal gonadocorticoids do

Contribute to sex drive and secondary sex characteristics

What does the adrenal medulla secrete

Epinephrine and norepinephrine

What is the function of epinephrine and norepinephrine

Help produce the sympathetic nervous system’s flight or flight response

Where is the pancreas located, and what are it’s functions

Between the duodenum and spleen, posterior to the stomach. Has both exocrine and endocrine functions

What does insulin do

Lowers blood glucose by promoting glucose uptake and storage

What does glucagon do

Raises blood glucose by promoting glycogen breakdown and glucose production

How are insulin and glucagon related

They are antagonistic hormones that work together in opposite ways to regulate blood glucose

What characterizes type I diabetes

Lack of insulin secretion; typically early onset. Treatment includes glucose monitoring and regular insulin injections

What characterizes type II diabetes

Normal or increased insulin secretion, but target cells have reduced insulin sensitivity. Typically later onset

How is type II diabetes managed according to the lecture

Blood glucose monitoring, diet, exercise, and medication

What do the gonads produce

Sex hormones and germ cells: oocytes in ovaries and spermatozoa in testes

Where are the ovaries located, and what hormones do they produce

Female gonads in the pelvic cavity; produce estrogen and progestorne

What are the major functions of estrogen

Supports female secondary sex characteristics, regulates the menstrual cycle, and promotes growth of the uterine lining

What are major functions of progesterone

Helps maintain the uterine lining and supports pregnancy

Where are the testes located, and what hormones do they produce

Male gonads in the scrotum; produce androgens such as testosterone

What are the major functions of testosterone

Supports male secondary sex characteristics, promotes sperm production, and helps maintain male reproductive function