The Endocrine System

Flashcards covering key concepts of the endocrine system, including organs, hormone functions, disorders, and the effects of aging.

What is the primary function of the endocrine system?

To regulate internal processes through the secretion of hormones into the blood.

What are hormones?

Chemical messengers that initiate physiological changes in cells.

List three pure endocrine organs.

Pituitary, pineal gland, thyroid gland, parathyroid glands, adrenal glands.

What type of glands secrete hormones?

Ductless glands.

What are amino acid-based hormones?

Hormones made from modified amino acids, peptides, or proteins.

What are steroids?

Hormones derived from cholesterol.

How do hormones bind to cells?

They bind to specific receptors on target cells.

What is humoral secretion control?

Secretion in direct response to changing ion or nutrient levels in the blood.

What is neural secretion control?

Secretion stimulated by sympathetic nerve fibers.

What is hormonal secretion control?

Secretion initiated by hormones released from other glands.

What does the hypothalamus control in relation to the pituitary gland?

It controls the secretion of the anterior lobe of the pituitary gland.

What are releasing hormones?

Hormones that stimulate the release of other hormones from the pituitary gland.

How many hormones does the pituitary gland secrete?

Nine major hormones.

What is the adenohypophysis?

The anterior lobe of the pituitary gland consisting of glandular tissue.

What is the neurohypophysis?

The posterior lobe of the pituitary gland consisting of neural tissue.

What hormone does the anterior pituitary release in response to thyrotropic cells?

Thyroid stimulating hormone (TSH).

What is the primary function of ACTH?

Stimulates the adrenal cortex.

What hormones are produced by the anterior lobe of the pituitary?

TSH, ACTH, FSH, LH, MSH, GH, and Prolactin.

What is the role of antidiuretic hormone (ADH)?

Increases water retention in the kidneys.

What is the function of oxytocin?

Induces contractions of reproductive organs and ejects milk during breastfeeding.

What are pinealocytes?

Cells in the pineal gland that produce melatonin.

What does melatonin regulate?

Circadian rhythms.

What do thymic hormones do?

Stimulate the development and maturation of T lymphocytes.

What is calcitonin's function?

Lowers blood calcium levels.

What hormone is produced by the parathyroid glands?

Parathyroid hormone (PTH).

What is the primary function of the adrenal medulla?

Secretes epinephrine and norepinephrine in response to stress.

What is the primary function of the adrenal cortex?

Secretes corticosteroids.

What are mineralcorticoids?

Hormones involved in regulating salt and water balance, such as aldosterone.

What are glucocorticoids?

Hormones that help the body deal with stress, such as cortisol.

What hormone do alpha cells in the pancreas secrete?

Glucagon.

What hormone do beta cells in the pancreas secrete?

Insulin.

What are the two main types of gonads?

Testes and ovaries.

What hormones do testes primarily secrete?

Androgens.

What hormones do ovaries primarily secrete?

Estrogen and progesterone.

What is the function of atrial natriuretic peptide (ANP)?

Decreases blood volume and blood pressure.

What hormone does the placenta secrete during pregnancy?

Estrogens, progesterone, and HCG.

What is diabetes insipidus?

A condition where the pars nervosa does not make enough ADH.

What causes type 1 diabetes?

T cell–mediated autoimmune response destroys beta cells, leading to insufficient insulin secretion.

What is Graves’ disease?

The most common type of hyperthyroidism caused by abnormal antibodies stimulating TH secretion.

What is myxedema?

Adult hypothyroidism characterized by a low metabolic rate.

What is Cushing's syndrome?

Hypersecretion of glucocorticoid hormones.

What is Addison’s disease?

A disorder characterized by deficiencies of both mineralocorticoids and glucocorticoids.

What tissue does the thyroid gland develop from?

Endoderm on the floor of the pharynx.

How does aging affect hormone secretion?

Generally leads to a decrease in hormone-secreting cells and increased connective tissue.

What structural change is seen in the anterior pituitary with age?

Increase in connective tissue and lipofuscin.

Name a hormone that decreases with age.

Thyroid hormones.

What do parathyroid glands primarily maintain?

Calcium homeostasis.

What happens to GH levels as one ages?

Marked drops in secretion occur.

Describe the changes in the adrenal cortex with age.

Normal rates of glucocorticoid secretion continue.

What is the significance of the infundibulum in the pituitary gland?

It connects the pituitary gland to the hypothalamus.

What function do the adrenal hormones serve?

Help the body cope with danger, terror, or stress.

Growth Hormone (GH)

Produced by the pituitary gland, it stimulates growth and cell reproduction.

Thyroid Stimulating Hormone (TSH)

Produced by the anterior pituitary gland, it stimulates the thyroid gland to produce thyroid hormones (T3 and T4).

Adrenocorticotropic Hormone (ACTH)

Produced by the pituitary gland, it stimulates the adrenal cortex to produce cortisol.

Luteinizing Hormone (LH)

Produced by the anterior pituitary gland, it triggers ovulation in females and testosterone production in males.

Follicle Stimulating Hormone (FSH)

Produced by the anterior pituitary gland, it stimulates the growth of ovarian follicles in females and sperm production in males.

Prolactin (PRL)

Produced by the pituitary gland, it stimulates milk production in breast tissue after childbirth.

Oxytocin

Produced by the hypothalamus and released by the pituitary gland, it stimulates uterine contractions during childbirth and milk ejection during breastfeeding.

Antidiuretic Hormone (ADH)

Produced by the hypothalamus and released by the pituitary gland, it promotes water reabsorption in the kidneys.

Thyroxine (T4) and Triiodothyronine (T3)

Produced by the thyroid gland, they regulate metabolism, energy levels, and growth.

Calcitonin

Produced by the thyroid gland, it lowers blood calcium levels by inhibiting bone resorption.

Parathyroid Hormone (PTH)

Produced by the parathyroid glands, it regulates calcium levels in the blood by promoting bone resorption.

Insulin

Produced by the pancreas, it lowers blood sugar levels by facilitating the uptake of glucose into tissues.

Glucagon

Produced by the pancreas, it raises blood sugar levels by promoting the conversion of glycogen to glucose.

Epinephrine (Adrenaline)

Produced by the adrenal medulla, it increases heart rate, muscle strength, and blood pressure.

Norepinephrine (Noradrenaline)

Produced by the adrenal medulla, it prepares the body for 'fight or flight' responses.

Cortisol

Produced by the adrenal cortex, it helps control blood sugar levels, regulate metabolism, and reduce inflammation.

Aldosterone

Produced by the adrenal cortex, it regulates sodium and potassium levels, thus controlling blood pressure.

Estrogen

Produced mainly in the ovaries, it regulates the female reproductive system and menstrual cycle.

Progesterone

Produced mainly in the ovaries, it prepares the uterus for pregnancy and regulates the menstrual cycle.

Testosterone

Produced mainly in the testes, it regulates the male reproductive system and influences secondary sexual characteristics.

Melatonin

Produced by the pineal gland, it regulates sleep-wake cycles.