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Presentation

1. ORAL PRESENTATION ON COURSE TITLE; NEUROENDOCRINOLOGY (PHS 401) GROUP TOPIC; HYPOTHALAMIC PITUITARY ADRENAL (HPA) AXIS PRESENTED BY GROUP 7

2. OUTLINE INTRODUCTION TO HPA AXIS IMPORTANCE OF HPA IN HUMAN PHYSIOLOGY PRODUCTION OF CRH REGULATION OF CRH PRODUCTION AND FUNCTIONS PITUITARY GLAND: LOCATION AND FUNCTION PRODUCTION OF ACTH ADRENAL GLANDS: LOCATION AND FUNCTION PRODUCTION OF CORTISOL AND OTHER GLUCOCORTIDS NEGATIVE FEEDBACK LOOP POSITIVE FEEDBACK LOOP

3. CONT. REGULATION BY OTHER HORMONES AND NEUROTRANSMITTERS DYSREGULATION/DISORDERS OF HPA AXIS SYMPTOMS OF HPA AXIS DYREGULATION/DISORDERS TREATMENT OF DISORDERS OF HPA AXIS SUMMARY CONCLUSION

4. INTRODUCTION The Hypothalamic-Pituitary-Adrenal (HPA) plays a crucial role in regulating various physiological processes in the body. HPA is also known as Limbic hypothalamic pituitary adrenal axis(LHPA axis) Component of hpa axis; 1.Hypothalamus: Produces and secretes corticotropin-releasing hormone (CRH) in response to stress, emotions, and other signals. 2.Pituitary Gland: Receives CRH from the hypothalamus and responds by producing and secreting adrenocorticotropic hormone (ACTH). 3.Adrenal Glands: Receive ACTH from the pituitary gland and respond by producing and secreting glucocorticoids (such as cortisol), mineralocorticoids (such as aldosterone), and androgens.

5. COMPONENT OF HPA AXIS The hypothalamus is a small, irregularly shaped structure located in the diencephalon region of the brain. It is situated below the thalamus and above the brainstem, and is approximately the size of an almond. Functions of the HPA axis iclude; Regulation of Body Temperature, Hunger and Thirst, Sleep-Wake, Emotions and Behavior, Hormone Regulation, Stress Response, Reproductive Functions, Blood Pressure and Heart Rate, Electrolyte and Water Balance, and Pain Modulations.

6. IMPORTANCE OF HPA IN HUMAN PHYSIOLOGY Stress Response: regulates the body's response to stress, enabling adaptation and survival. Metabolism: influences glucose and lipid metabolism, energy storage, and weight management. Electrolyte and Water Balance: helps maintain electrolyte and water balance, regulating blood pressure and fluid balance. Immune System: modulates the immune response, preventing excessive inflammation and autoimmune diseases. Reproductive Function:regulates puberty, menstruation, fertility, and pregnancy. Othe aspect in which HPA axis plays significant role are, CVS,mood & cognitive function,sleep wake cycle,bone health,

7. PRODUCTION OF CORTICOTROPIN-RELEASING HORMONE (CRH) CRH is primarily produced by the parvocellular neurosecretory cells within the paraventricular nucleus (PVN) of the hypothalamus. CRH is also synthesized in peripheral tissues and produced in response to stress. CRH can suppress appetite, increase subjective feelings of anxiety Increased CRH production has been observed to be associated with Alzheimer's disease. Once produced, CRH is released from the neurosecretory terminals of these neurons into the median eminence, a part of the hypothalamus. In the anterior pituitary, CRH stimulates the corticotroph cells to secrete adrenocorticotropic hormone (ACTH).

8. REGULATION OF CRH PRODUCTION AND FUNCTIONS Functions of CRH; Stress Response: CRH is the central driver of the hypothalamic-pituitary-adrenal (HPA) axis, coordinating the body’s response to stress by increasing cortisol levels1. Behavioral Effects: CRH also affects various brain regions, influencing behaviors such as anxiety, appetite suppression, and attention. Regulation of CRH is by; Negative Feedback: Elevated cortisol levels provide negative feedback to the hypothalamus and pituitary gland, reducing the release of CRH and ACTH to maintain balance.

9. PITUITARY GLAND: LOCATION AND FUNCTION The pituitary gland, also known as the hypophysis, is a small, pea-sized gland located at the base of our brain, just below the hypothalamus. The pituitary gland acts as our body’s “master gland” because it controls the functions and regulate other endocrine gland . The functions of master gland involve regulations of growth and development, electrolyte and water balance, reproductive processes, thyroid function, adrenal function, lactation and milk production, stress response, body temperature, appetite and satiety and Control of metabolism . Homones of pituitary gland are; ACTH, TSH,GH, PRL, FSH, LH, MNS,OX, and VP.

10. PRODUCTION OF ACTH Adrenocorticotropic hormone (ACTH) is a hormone produced by the pituitary gland that plays a crucial role in regulating the production of cortisol and other glucocorticoids by the adrenal glands. FUNCTIONS OF ACTH: 1. Stimulates cortisol production 2. Regulates adrenal function 3. Modulates immune response 4. Influences electrolyte balance ACTH production is regulated by: 1. Corticotropin-releasing hormone (CRH) 2. Glucocorticoid feedback 3. Stress

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12. ADRENAL GLANDS: LOCATION AND FUNCTION The adrenal glands are two small, triangular-shaped glands located on top of the kidneys. They are situated in the retroperitoneal space, near the spine. The adrenal glands produce and secrete several hormones that play crucial roles in the body's response to stress, regulating blood pressure, electrolyte balance, and metabolism. Cortisol which regulates metabolism, reduces inflammation, and helps the body respond to stress. Aldosterone: Maintains BP and electrolyte balance. Adrenaline and Noradrenaline: Increase heart rate, BP, and energy supply during stress. Androgens: Contribute to the development of secondary sexual characteristics and reproductive function.

13. PRODUCTION OF CORTISOL AND OTHER GLUCOCORTIDS In response to stress, the hypothalamus releases corticotropin-releasing hormone (CRH) CRH stimulates the anterior pituitary gland to secrete adrenocorticotropic hormone (ACTH). ACTH travels through the bloodstream to the adrenal glands, where it binds to receptors on cells in the zona fasciculata and zona reticularis. Functions of Cortisol and Glucocorticoids; Metabolism Regulation Immune Response. Stress Response Blood Pressure Regulation:

14. NEGATIVE FEEDBACK LOOP Negative Feedback: Elevated cortisol levels provide negative feedback to the hypothalamus and pituitary gland, reducing the release of CRH and ACTH to maintain hormone balance. A negative feedback loop is a regulatory mechanism that helps maintain homeostasis by reversing or counteracting changes in a system. IMPORTANCE OF NEGATIVE FEEDBACK LOOP: 1. Maintains homeostasis 2. Prevents excessive cortisol production (Cushing's syndrome) 3. Prevents deficient cortisol production (Addison's disease) 4. Regulates stress response 5. Ensures proper bodily functions

15. POSITIVE FEEDBACK LOOP A positive feedback loop is a process in which the end products of an action cause more of that action to occur. It amplify the original effect. This is in contrast to a negative feedback loop, which works to reduce or counteract changes. Example of positive feedback loop; Parturiton:During labor, the pressure of the baby’s head against the cervix stimulates the release of oxytocin which increases uterine contractions (process continue untill the baby is delivered) Blood Clotting:When a blood vessel is injured, platelets adhere to the site and release chemicals that attract more platelets (process continues untill clot is formed to stop the bleeding)

16. REGULATION BY OTHER HORMONES AND NEUROTRANSMITTERS Cortisols are steroid hormones produced by the adrenal cortex in the adrenal gland. They help us to respond to stress, regulate body metabolism. Neurotransmitters are chemical messenger that transmits signal from a neuron to target cells e.g dopamine, serotonin, ACTH and glutamatem Cortisol regulation is also influenced by other hormones and neurotransmitters, which includes: Insulin and thyroid hormones stimulates cortisol production. High glucagon level and prolactin stimulates cortisol production. Neurotransmitters like serotonin& Dopamine can Inhibit Cortisol production while Acetylcholine stimulates the production of cortisol.

17. DISORDERS OF HPA AXIS AND THEIR CAUSES Cushing’s Syndrome: excessive production of cortisol. Addison’s Disease: insufficient production of cortisol and aldosterone. Depression and Anxiety Disorders: dysregulation of the HPA axis Post-Traumatic Stress Disorder (PTSD): Chronic stress and trauma which can lead to long-term changes in HPA axis function. Other disorders include; Metabolic Syndrome, Chronic Fatigue Syndrome (CFS) and Autoimmune Diseases.

18. SYMPTOMS OF HPA AXIS DYSREGULATION/DISORDERS

19. TREATMENT OF DISORDERS OF HPA AXIS Cushing's syndrome: Surgery, medications (e.g., ketoconazole), or radiation therapy Addison's disease: Glucocorticoid and mineralocorticoid replacement therapy Adrenal insufficiency: Glucocorticoid replacement therapy Hypopituitarism: Hormone replacement therapy (e.g., glucocorticoids, thyroid hormone) Others; Healthy Diet, Therapy, Prioritize Sleep, Regular Exercise, Avoid Stimulants and Mindfulness and Meditation.

20. SUMMARY/CONCLUSION The Hypothalamic-Pituitary-Adrenal (HPA) Axis, is a complex neuroendocrine system, regulating various bodily functions, including stress response, metabolism, electrolyte balance, immune response, mood, and reproductive function. The HPA Axis consists of the hypothalamus, pituitary gland, and adrenal glands, which interact through negative and positive feedback loops.

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