Hypothalamo-Pituatory Axis PDF BIOL750 28 Aug 2024

The Hypothalamic-Pituitary Axis Dr. Nemat Khan [email protected] Office: A03024 Recent Advances in Endocrinology BIOL750  Presentation Title Goes Here DD Month 20XX ku.ac.ae 2 Endocr...

The Hypothalamic-Pituitary Axis Dr. Nemat Khan [email protected] Office: A03024 Recent Advances in Endocrinology BIOL750  Presentation Title Goes Here DD Month 20XX ku.ac.ae 2 Endocrinology Endocrinology is the understanding of hormone secretion, hormone action, and principles of feedback control. Endocrine glands are part of your endocrine system, and they secrete hormones. The endocrine system is evaluated primarily by measuring hormone concentrations. Endocrine glands secrete hormones directly into the bloodstream, while exocrine glands secrete other substances through a duct, either into the body or onto its surface.  Presentation Title Goes Here DD Month 20XX ku.ac.ae 3 Endocrinology Endocrine glands Exocrine glands do not have any ducts have ducts that release substances secrete various substances, including sweat, only secrete hormones sebum, enzymes, and mucus secrete substances into an organ or onto the secrete hormones directly into the bloodstream surface of the body Pancreas: Is this Endo or Exocrine gland?  Presentation Title Goes Here DD Month 20XX ku.ac.ae 4 Pancreas Exocrine Enzymes: Proteases: Lipases: Amylase: Endocrine Hormones: Insulin (beta cells) Glucagon (alpha cells) islet of Langerhans  Presentation Title Goes Here DD Month 20XX ku.ac.ae 5 Exocrine vs Endocrine glands Exocrine glands : Endocrine glands: Salivary glands: Salivary glands in the mouth produce saliva, Pituitary gland: The pituitary gland sits at the base of the brain and which helps with digestion as well as lubrication and protection of produces hormones for various functions, such as growth and the mouth and throat. metabolism. Sebaceous glands: Sebaceous glands on the skin secrete oil, Hypothalamus: The hypothalamus is part of the brain that produces or sebum, which helps lubricate and protect the skin. hormones. The hypothalamus and the pituitary gland regulate the rest Sweat glands: Sweat glands on the skin release sweat to help of the endocrine system. control body temperature. Thyroid gland: The thyroid gland produces thyroid hormones, which Mammary glands: The mammary glands in the breasts produce help support various functions in the body. milk for chest or breastfeeding. Adrenal glands: The two adrenal glands sit above the kidneys. The Pancreas: The pancreas releases digestive enzymes into adrenal glands help control functions such as heart rate and blood the small intestine to help support digestion. pressure. Stomach glands: Exocrine glands in the stomach release Pancreas: The pancreas is an organ in the abdomen that creates digestive enzymes to help break down food, regulate stomach pH hormones to support digestion and normal blood sugar levels. levels, and support the absorption of nutrients. Ovaries: The ovaries form part of the female reproductive Brunner glands: Brunner glands are in the duodenum, which is system and create estrogen and progesterone. the first section of the small intestine. The Brunner glands secrete Testicles: The testicles form part of the male reproductive mucus to protect the small intestine from stomach acid. system and produce sperm and testosterone.  Presentation Title Goes Here DD Month 20XX ku.ac.ae 6 Hormones The term hormone - derived from a Greek phrase meaning “to set in motion,” aptly describes the dynamic actions of hormones as they elicit cellular responses and regulate physiologic processes through feedback mechanisms. Cholesterol is a precursor to many important steroid hormones like estrogen, testosterone, and progesterone, Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods ☺  Presentation Title Goes Here DD Month 20XX ku.ac.ae 7 Mechanisms of hormone release a) Humoral: in response to changing levels of ions or nutrients in the blood (Example?) Insulin b) Neural: stimulation by nerves (Example?) Oxytocin, ADH (hypothalamus) c) Hormonal: stimulation received from other hormones (Example?) Hypothalamic-pituitary axis  Presentation Title Goes Here DD Month 20XX ku.ac.ae 8 Neuroendocrine system & Neurohormones The neuroendocrine system is the mechanism by which the hypothalamus maintains homeostasis, regulating reproduction, metabolism, eating and drinking behaviour, energy utilization, osmolarity and blood pressure etc. Hypothalamus regulates Pituitary Functions. Neurons in the hypothalamus secrete releasing hormones and inhibiting hormones in anterior pituitary gland. The secretory activity of many endocrine Neurohormone, any of a group of substances that glands(Pituitary, Thyroid, Adrenal and Gonads) is are produced by specialized neurosecretory cells of controlled by the nervous system. the nervous system, Examples? oxytocin and vasopressin (neurohypophysial hormones)  Presentation Title Goes Here DD Month 20XX ku.ac.ae 9 Neurotransmitters vs Neurohormones  Presentation Title Goes Here DD Month 20XX ku.ac.ae 10 Master Regulator – Pituitary gland Melanocyte-stimulating hormone  Presentation Title Goes Here DD Month 20XX ku.ac.ae 11 Hypothalamic-pituitary axis HPT HPG HPA (depending on target organs which is being affected)  Presentation Title Goes Here DD Month 20XX ku.ac.ae 12 Hypothalamus role? Controls many fundamental physiological activities including body temperature, hunger, thirst, sleep and some ANS functions. The interface between the endocrine and the nervous systems – it receives nerve fibres from nearly all areas of the brain. In response to various signals/stimuli, the hypothalamus can: Synthesise and release neurohormones into the circulation via the posterior pituitary,  Presentation Title Goes Here DD Month 20XX ku.ac.ae 13 Hypothalamus role? Synthesise and release hypophysiotropic hormones (releasing hormones) into the hypophyseal portal blood system to regulate hormone release from the anterior pituitary. Send neural signals to regulate the release of sympathetic nervous system hormones from the adrenal medulla The hypothalamus is connected to the Anterior Pituitary via the Hypothalamic-Hypophysial Portal System (HHPS).  ku.ac.ae Hypothalamic Releasing and Inhibiting hormones Hypothalamic -Releasing hormones : Growth hormone (GH) Prolactin (PRL) CRH (Corticotropn releasing Hormone) Adrenocorticotrophic hormone Stimulates the release of ACTH (ACTH) TRH (Thyrotropin-Releasing Hormone) Melanocyte stimulating hormone Stimulates the release of TSH (MSH) GnRH (Gonadotropin-Releasing Hormone ) Thyroid stimulating hormone (TSH) Follicle stimulating hormone (FSH) stimulates the release of FSH& LH Luteinising hormone (LH) GHRH(Growth Hormone Releasing Hormone) Stimulates the release of GH Hypothalamic Inhibiting Hormones : Dopamine MIH (melanotropin-inhibiting hormone) Inhibits the secretion of PRL inhibits the secretion of MSH. SRIF (Somatostatin Release Inhibiting Factor) Inhibits the secretion of STH  Presentation Title Goes Here DD Month 20XX ku.ac.ae 15 Hypothalamic-pituitary axis  ku.ac.ae Thank you ! 16