Endocrine Gland Review PDF

ENDOCRINE GLAND 1. Primary Functions of the Endocrine System: Hormone Secretion: Regulates physiological processes. Functions Include: o Maintaining homeostasis (balance in body conditions). o Regulating growth and development. o Controlling metabolic ac...

ENDOCRINE GLAND 1. Primary Functions of the Endocrine System: Hormone Secretion: Regulates physiological processes. Functions Include: o Maintaining homeostasis (balance in body conditions). o Regulating growth and development. o Controlling metabolic activities. o Coordinating stress responses. 2. Insulin and Its Function: Produced by: Pancreas. Function: Regulates glucose metabolism by helping cells absorb glucose, thus lowering blood glucose levels. 3. Hormones Produced by the Thyroid Gland: Hormones: Thyroxine (T4) and Triiodothyronine (T3). Role: Regulate metabolism, energy production, and growth and development. 4. Endocrine vs. Exocrine Glands: Endocrine Glands: Secrete hormones directly into the bloodstream (e.g., pancreas). Exocrine Glands: Secrete substances through ducts (e.g., pancreas also secretes digestive enzymes). 5. Hormone That Stimulates Uterine Contractions: Hormone: Oxytocin. Target: Smooth muscle cells in the uterus. Function: Stimulates uterine contractions during childbirth. 6. Negative Feedback in Hormone Regulation: Concept: Negative feedback prevents excessive hormone production. It works by inhibiting the process that caused the hormone release. Example: The release of insulin lowers blood glucose, and as glucose levels normalize, insulin release decreases. 7. Example of Hormone-Regulated Feedback Loop: Example: Parathyroid Hormone (PTH) regulation of blood calcium levels.  o When calcium levels fall, PTH is released to increase calcium levels by releasing calcium from bones and enhancing absorption in the intestines. 8. Modes of Action: Steroid vs. Peptide Hormones: Steroid Hormones: Derived from cholesterol, can enter cells, bind to intracellular receptors, and affect gene expression (e.g., cortisol). Peptide Hormones: Bind to cell membrane receptors, activating second messenger systems (e.g., insulin). 9. Example Hormones: Steroid Hormone: Cortisol – Regulates metabolism and immune responses. Peptide Hormone: Insulin – Regulates glucose metabolism by promoting glucose uptake into cells. 10. Hormones Released by Different Glands: A. Thyroid Gland: Hormones: Thyroxine (T4) and Triiodothyronine (T3). Target: Various body tissues. Action: Regulate metabolism, energy production, and growth. Regulation: Stimulated by Thyroid-Stimulating Hormone (TSH) from the pituitary gland. Negative feedback loop controls release. B. Pituitary Gland: Hormone: Growth Hormone (GH). Target: Bones, muscles, and other tissues. Action: Stimulates growth and cell reproduction. Regulation: Controlled by Growth Hormone-Releasing Hormone (GHRH) and Growth Hormone-Inhibiting Hormone (GHIH) from the hypothalamus. C. Pancreas: Hormone: Insulin. Target: Liver, muscle, and adipose tissue. Action: Promotes glucose uptake, storage, and inhibits glucose production. Regulation: Released in response to high blood glucose levels and inhibited by low glucose levels. D. Adrenal Glands:  Hormone: Cortisol. Target: Liver, muscle, and adipose tissue. Action: Regulates metabolism, reduces inflammation, and affects immune response. Regulation: Controlled by the hypothalamus-pituitary-adrenal (HPA) axis; regulated by Corticotropin-Releasing Hormone (CRH) and ACTH. E. Ovaries (Female) / Testes (Male): Estrogen (Female): o Target: Female reproductive organs, breast tissue, and other tissues. o Action: Regulates the menstrual cycle and promotes secondary sexual characteristics. o Regulation: Stimulated by FSH and LH from the pituitary gland. Testosterone (Male): o Target: Testes, muscles, and other tissues. o Action: Stimulates sperm production, promotes secondary sexual characteristics, and influences muscle mass. o Regulation: Stimulated by LH from the pituitary gland. F. Parathyroid Glands: Hormone: Parathyroid Hormone (PTH). Target: Bones and kidneys. Action: Increases blood calcium levels by stimulating calcium release from bones and enhancing calcium reabsorption in kidneys. Regulation: Triggered by low blood calcium levels, inhibited by high levels. G. Pineal Gland: Hormone: Melatonin. Target: Various tissues, especially the brain. Action: Regulates sleep-wake cycles (circadian rhythms). Regulation: Controlled by light-dark cycles; secretion increases in darkness and decreases in light. CARDIOVASCULAR SYSTEM 1. Major components of blood and their respective percentages: o Red blood cells: 45% o Plasma: 55% o White blood cells and platelets: