Question | Answer |
Endocrine Glands | Develop from all 3 embryonic germ layers. Ductless. Secrete hormones directly into the blood stream that bind to receptors on cells. Help maintain homeostasis. Endocrinology. |
Endocrine vs. Nervous system (Both control) | Endocrine: slower. lasts longer. has widespread general effects & can affect any cell in the body. Uses hormones. Nervous: fast. need direct contact. Neurotransmitters. |
Hormones | Chemical messengers. Released into blood by endocrine glands that regulate specific body functions. |
Tropic hormones | Hormones that affect the release of other hormones. Act on glands. Not cells. Ex. Gonadotropins (LH & FSH) affect the release of sex hormones from the gonads. |
Three structural types of hormones | Peptides: chains of amino acids. Most common. ex. growth hormone (GH). Steroids: lipid derived from cholesterol. es. testosterone. Biogenic Amines: produced by altering a specific amino acid. ex. thyroid hormone (TH) |
Hypothalamus: 3 endocrine functions | 1. Produces regulatory hs that either stimulate or inhibit anterior pituitary hormone secretion. 2. Antidiuretic & oxytocin stored & released from posterior pituitary. 3. Overseer of ANS. Stimulates secretion of adrenal medulla-sympathetic innervation. |
Pituitary Gland (Hypophysis) "master gland" | Composed of Anterior Pituitary (Adenohypophysis), Hypophyseal portal system, and Posterior Pituitary (Neurohypophysis). |
Anterior Pituitary (Adenohypophysis) | Composed of glandular tissue. |
Hypophyseal portal system | Portal veins that shunt blood carrying regulatory hormones from hypothalamus to anterior pituitary before blood returns to the heart. |
Posterior Pituitary (Neurohypophysis) | Part of the brain. Nervous tissue. |
Posterior Pituitary Hormones | Made in hypothalamus. Antidiuretic hormone (Vasopressin) & Oxytocin. |
Antidiuretic hormone (Vasopressin) | Initiates water reabsorption during dehydration. Increases BP through vasoconstriction. Hypersecretion causes edema. Hypsecretion causes Diabetes Insipidus. More of this released at night-pee less. Target organ: kidney. |
Oxytocin | Induces smooth muscle contraction in reproductive organs. Uterine contractions and milk ejection. Surges during orgasm. |
Anterior Pituitary Hormones | FLAT PGM. Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), Adenocorticotropic Hormone (ACTH), Thyroid-Stimulating Hormone (TSH), Prolactin (PRL), Growth Hormone (GH), Melanocyte-Stimulating Hormone (MSH). |
Follicle-Stimulating Hormone (FSH) & Luteinizing Hormone (LH) | Help with reproduction. You go into puberty when these surge. Precocious puberty-happens too young. |
Adenocorticotropic Hormone (ACTH) | Affects adrenal gland. |
Prolactin (PRL) | Creates milk. |
Growth hormone disorders | Pituitary Dwarfism-hyposecretion of GH in children. Pituitary Gigantism-hypersecretion of GH in children. Ancromegaly-hypersecretion of GH during adulthood (epiphyseal plates closed). Bones get wider & thicker. |
Pineal gland | Small. End of short stalk on roof of diencephalon. Produces melatonin-helps regulate circadian rhythm-sleep/wake cycles. |
Thyroid gland | Butterfly shaped. Inferior to larynx. Largest pure endocrine gland. Produces thyroid hormone & calcitonin. |
Thyroid hormone (T3-triiodothyronine & T4-thyroxine) | Increases metabolic rate. |
Calcitonin | Lowers blood calcium level. Decreases osteoclast activity & increases osteoblast activity. |
Disorders of Thyroid Gland | ENDEMIC GOITER-dietary iodine deficiency. HYPERTHYROIDISM-excessive TH production. Graves disease-loss of thyroid feedback control. Exophtalmos (eyes pop), tachycardia. HYPOTHYROIDISM-decreased TH. Fatigue, weakness, dry skin, weight gain, reduced libido. |
Parathyroid Glands | Lie on posterior surface of thyroid gland. Microscopic. Produce parathyroid hormone (PTH). |
Parathyroid Hormone (PTH) | Increases blood Calcium concentration. Increases osteoclast activity and decreases osteoblast activity. Opposite effect of calcitonin. Antagonistic hormones. |
Thymus | Lower neck & midiastinum. Yellows & atrophies after puberty. Produces thymic hormones: thymopoietin & thymosins. They stimulate differentiation, growth, & maturation of T-lymphocytes (WBCs). |
Adrenal (Suprarenal) Glands | Pyramidal organs on kidney surface. |
Adrenal cortex | Aldosterone-water & salt retention-kidney. Cortisol-helps body deal with stressful situations. Androgens-sex hormones. |
Adrenal medulla | Epinephrine (adrenaline) & Norepinephrine-enhance fight or flight response. |
Corticosteroids | Steroid hormones from the adrenal cortex. ex. cortisol. Act on the immune sys by blcoking inflammation. Inhibit WBCs-sede effect to them is increased susceptibility to infection. Treat inflammation diseases-R arthritis, Lupis, Inflammatory bowel disease. |
Cushings Syndrome | Hypersecretion of cortisol. Symptoms: Re-distributed body obesity-from arms and legs to trunk. Moon face. Buffalo hump. Kidney stones. Skin becomes fragile and thin. |
Addison Disease | Hyposecretion of cortisol & sometimes aldosterone. Symptoms: Weight loss. General fatigue. Hypotesion. Skin darkening. |
Pancreas | Posterior wall of abdominal cavity. Pancreatic islets (Islets of Langerhans). Produces Glucagon-alpha cells. Glycogen breakdown in liver cells. Insulin-Beta cells. Cells take up glucose. |
Diabetes mellitus | Type 1: diminished production of insulin by pancreatic islet cells. Develops suddenly. Type 2: develops more slowly. Gestational: during pregnancy. 20-50% chance of development of maternal Type 2 later. |