The endocrine system

Hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

Hypothalamus

brain region controlling the pituitary gland

Hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

Hypothalamus

brain region controlling the pituitary gland

Hypothalamus is a

neuroendocrine gland

Pituitary gland

the master gland of the endocrine system

Parts of the pituitary gland

anterior pituitary and posterior pituitary

Negative feedback mechanism of hormone regulates

the concentration of hormones in blood within a narrow range.

Anterior pituitary hormones

GH, TSH, ACTH, FSH, LH, PRL, MSH

TSH (thyroid stimulating hormone)

Stimulates thyroid gland to produce thyroid hormones

ACTH (adrenocorticotropic hormone)

Stimulates adrenal cortex to release glucocorticoids (cortisol)

FSH (follicle stimulating hormone) and LH (luteinizing hormone)

stimulate the gonads (testes and ovaries) to produce gametes and sex hormones.

Prolactin (PRL)

Produced only after childbirth and causes the mammary glands to produce milk

Growth Hormone (GH)

promotes skeletal and muscular growth and stimulates the rate of protein synthesis.

Gigantism

abnormal growth of the entire body due to excessive secretion of growth hormone before puberty

Acromegaly

abnormal enlargement of hands and feet due to excessive secretion of growth hormone after puberty

Pituitary dwarfism

abnormally short height caused by under secretion of growth hormone from the pituitary gland

Posterior pituitary hormones

Antidiuretic hormone (ADH), Oxytocin

The function of ADH is to

conserve water

Oxytocin

stimulates uterine contractions during childbirth and milk letdown during breastfeeding.

Diabetes Insipidus (DI)

insufficient secretion of ADH

Symptoms of diabetes insipidus

Produce large amounts of urine, resulting in severe dehydration and loss of important ions

thyroid gland

endocrine gland that surrounds the trachea in the neck

Thyroid hormones (T3 and T4)

Iodine-containing hormones that control the body's metabolic rate

Functions of thyroid hormones

Calorigenic effect: Regulate the rate of metabolism

CVS: Increases HR, cardiac contractility and cardiac output

CNS: important for normal mental functions

Growth: Essential for normal growth in children

Reproduction: important for normal reproductive physiology

Hyperthyroidism

over secretion of thyroid hormones

Hyperthyroidism symptoms

heat intolerance, weight loss, sweating, anxiety, irritability, hyperactivity, palpitations, protrusion of eyes

Hypothyroidism

hyposecretion of the thyroid gland causing low thyroid levels in the blood

hypothyrodism symptoms

lethargy, weight gain, loss of hair, slower pulse, cold intolerance, lowered body temperature

Calcitonin

secreted by the thyroid gland; decreases blood calcium levels

parathyroid glands

four small glands on the posterior of the thyroid gland

Parathyroid hormones (PTH)

raises the blood calcium level if it is too low

Hypoparathyroidism

hyposecretion of the parathyroid glands

Hyperparathyroidism

overproduction by the parathyroid glands

Adrenal gland

sits atop our kidneys and secretes hormones involved in the stress response

adrenal cortex

the outer portion of the adrenal glands

Adrenal cortex hormones

Glucocorticoids, Mineralocorticoids, Sex hormones

Adrenal medulla hormones

Epinephrine (adrenaline) and Norepinephrine (noradrenaline)

Glucocorticoids (cortisol)

-Regulate carbohydrate, protein and fat metabolism

- Increase blood glucose level

- anti-inflammatory--> immunosuppression

- active in stress response

- repair of damaged issue

Mineralocorticoids (aldosterone)

Regulate electrolyte and fluid homeostasis

Renin-angiotensin-aldosterone system (RAAS)

a hormone cascade pathway that helps regulate blood pressure and blood volume

Addison's disease

a condition that occurs when the adrenal glands do not produce enough cortisol or aldosterone

Cushing's syndrome

hypersecretion of cortisol

Cushing's syndrome symptoms

central obesity, moon face, wasted extremities, buffalo hump, osteoporosis, amenorrhea, proximal muscle weakness, abdominal striae, high blood pressure

Hypothalamic-pituitary-adrenal axis (HPA) suppression during the period of steroid therapy

Tapering of the dose of steriod must be done carefully to avoid possible cortisol deficiency

Endocrine pancreas (islets of Langerhans)

-contain 3 cell types

-alpha cells make glucagon

-beta cells make insulin

-delta cells make somatostatin

Insulin

decreases blood glucose levels

Glucagon

increases blood glucose levels

Diabetes mellitus (DM)

insulin is not secreted adequately or tissues are resistant to its effects results in hyperglycemia