Physiology Chapter 23: Endocrine Control PDF

**[Chapter 23 -- Endocrine Control of Growth and Metabolism]** **[23.2 Adrenal Glucocorticoids]** **[3. Diagram the HPA pathway in detail, including feedback signals and cellular mechanisms of action]**A diagram of a cell structure Description automatically generated with medium confidence \*This...

**[Chapter 23 -- Endocrine Control of Growth and Metabolism]** **[23.2 Adrenal Glucocorticoids]** **[3. Diagram the HPA pathway in detail, including feedback signals and cellular mechanisms of action]**A diagram of a cell structure Description automatically generated with medium confidence \*This was pretty much covered in CH.7 but it didn't show the specific targets of cortisol \***Cortisol = mediation of long-term stress** - **Metabolic effects (mostly catabolic)** - Promotes gluconeogenesis - Breakdown of SKM proteins - Enhances lipolysis - Suppresses immune system - Causes negative calcium balance - Influences brain function [4. Identify the hallmarks of **hypercortisolism and hypocortisolism**, and explain the possible causes] - **[Hypercortisolism]** -- too much cortisol - Caused by adrenal tumor secretes lots of cortisol - **Cushing's disease/syndrome** - Symptoms: hyperglycemia & tissue wasting - **[Hypocortisolism]** -- too little cortisol - Hyposecretion of all adrenal steroid hormones - **Addison's disease** - Symptoms - Hypoglycemia, fatigue, lack of appetite **[22.3 Thyroid Hormones]** **[7. Diagram the thyroid hormones control pathway, including feedback signals and cellular mechanisms of action. ]**  T3 = biologically active but very short half life T4 = longer half-life but inactive until it converts into T3 active form [8. Identify the hallmarks of **hyperthyroidism and hypothyroidism**, and distinguish between primary and secondary thyroid pathologies. ] - **Goiters** -- enlarged thyroid gland - Due to BOTH hypo & hyper thyroidism - **Hyperthyroidism** -- thyroid gland secretes too much hormone - Caused by Grave's disease - Accompanied by exophthalmos (bulging eyeballs) - Thyroid gland tumors can cause goiters - Increase O2 consumption, heat production, HR, & contractility - **Hypothyroidism** -- lack of hormone - Can be caused by lack of iodine (causes goiter) - Autoimmune - Treatment of other disorders - Slows metabolic rate & less O2 consumption, HR, & slower nervous system A diagram of a medical procedure Description automatically generated **[23.4 Growth Hormone]** [9. List the factors that influence normal growth] - Growth hormone & other hormones - Adequate diet - Absence of chronic stress - Genetics [11. Identify the hallmarks of hypersecretion and hyposecretion of **growth hormone** in children and adults.] - Hypersecretion - In children **giantism** - In adults **acromegaly** - Growth plates have calcified so increased bone deposits - Hyposecretion - **dwarfism** **[23.6 Calcium Balance]** [15. Explain the physiological functions of calcium] - Calcium (Ca2+) - Important signal molecule - Cements cell junctions - Cofactor in coagulation cascades - Plasma Ca2+ concentrations affect excitability of neurons and all muscle types [16. Diagram the distribution of calcium in the body, and explain the factors that influence its movement between compartments.] - Distributed among 3 compartments - Extracellular fluid - Intracellular Ca2+ - Extracellular matrix (bone) Total calcium in body = intake -- output - **Intake** Ca2+ ingested from diet - **Output** loss, primarily from kidneys [17. Diagram the endocrine control of plasma calcium concentration by parathyroid hormone and calcitriol, and calcitonin including the cellular mechanisms of action of each hormone] - **Parathyroid hormone (PTH)** -- raises plasma Ca2+ concentration - Stimulated for release by low plasma Ca2+ levels - Raises plasma Ca2+ levels 3 ways - PTH mobilizes Ca2+ from bone - PTH enhances renal absorption of Ca2+ - PTH indirectly increases intestinal absorption of Ca2+ via its effect on **calcitriol** - **Calcitriol / vitamin D** - Primary hormone involved in Ca2+ uptake - Regulated by **PTH** - Facilitates renal absorption - Mobilizes Ca2+ out of bone - **Calcitonin** from thyroid gland minor role in daily Ca2+ balance - Produced by C cells of thyroid gland - Released when plasma Ca2+ concentration is high - Lead to Ca2+ excretion via kidneys  **PTH** raises Ca2+ **Calcitriol / vitamin D** = enhance Ca2+ uptake / raise Ca2+   **Calcitonin** does the opposite & decreases Ca2+ levels Released by thyroid A diagram of a complex of vitamins Description automatically generated with medium confidence