The endocrine system, vital for responding to environmental changes, is key for MCAT success. This video covers hormone types, major endocrine organs, and hypothalamic signaling pathways. Peptide hormones (polar, surface-acting) and steroid hormones (non-polar, nucleus-acting) define cellular responses. Starting with the hypothalamus, you’ll learn its role in regulating organs like the pituitary, thyroid, adrenal glands, pancreas, and gonads. Critical axes such as HPA, HPG, and HPT pathways are outlined, emphasizing test-relevant hormones like ACTH, TSH, LH, FSH, and more. Whether it’s cortisol’s stress response or insulin’s glucose regulation, this concise guide simplifies complex systems for test day success.