The Endocrine System

(first 33, 1/13/2026)

Symptoms of Diabetes Mellitus

Fatigue, weight loss without trying, appetite increase, thirst frequent urinating

Three P’s for Diabetes

Polydipsia (increased thirst/drinking), Polyphagia (increased eating), Polyuria (increased urinating)

Urinalysis

Clinical Test #1 for Diabetes; sample of urine is tested with a dipstick and is used to see if excess glucose in in the urine (meaning so much in blood that its spilling into kidneys)

Serum Blood Glucose Test

Clinical Test #2 for Diabetes'; patient fasts for 8 hours and a vial of blood is drawn to measure level of glucose in plasma

Normal Glucose Level

70-100 mg/dl

Oral Glucose Tolerance Test (OGTT)

Clinical Test #3 for Diabetes; patient chugs liquid with 100g of glucose and over the next 3 hours, 5 vials of blood are drawn and tested for glucose; Normal=glucose rises fast then falls to below 140mg/dl in the next 2 hours

Endocrine System

system of glands that secrete hormones to control the body’s functions

Important Brain Glands

Hypothalamus, Pituitary gland, and Pineal gland

Important Neck Glands

Thyroid and Parathyroid glands

Important Abdomen Glands

Pancreas and Adrenal Glands

Important Chest-Thoracic Gland

Thymus

Important Pelvis Gland

Testes/Ovaries

2 Main Control Systems of the Body

Endocrine and Nervous System

Endocrinology

study of hormones and endocrine organs

Nervous System (from chart)

Quickly initiate short duration responses, acts via action potentials and neurotransmitters, acts at specific locations determined by axon pathways, neurotransmitters act over very short distances

Endocrine System (from chart)

Slowly initiate long duration responses, act via hormones released into blood, acts at diffuse locations (anywhere blood reaches), hormones act over long distances

Exocrine Glands

have ducts; produce non-hormonal substances (saliva, sweat); secrete products into ducts to carry secretion to outside surface or into an organ cavity

Endocrine Glands

Produce hormones; lack ducts; secrete directly into blood

Glands with both Endocrine and Exocrine Functions

Pancreas, Gonads, and Placenta (secrete directly into bloodstream and out into ducts into organs or body surfaces)

Hormones

chemical messengers of endocrine system (travel long distances in blood)

Water-based Soluble Hormones

Amine, Peptide/Protein, and Eicosanoid hormones; all amino acids EXCEPT thyroid hormone; CANNOT ENTER CELL (think phospholipids)

Lipid-based Soluble Hormones

Synthesized from cholesterol; bind to receptor inside the cell; steroid and thyroid hormones; directly activate genes

G-Protein “Second Messenger”

Amine, Peptide, and Protein hormones use this cell pathway; called G-Protein because it’s made of Guanine compounds; these hormones NEVER MAKE IT TO CELL

G-Protein Step 1

hormone binds to G-Protein

G-Protein Step 2

enzymes move around in cytoplasm and turn ATP into cyclic AMP molecule

G-Protein Step 3

cAMP activates (called cascade)

G-Protein Step 4

cell responds and does what the hormone wants

Lipid Soluble Hormones Step 1

Lipid-based hormone diffuses right through plasma membrane

Lipid Soluble Hormones Step 2

Receptor-hormone complex enters nucleus and binds to specific region of DNA

Lipid Soluble Hormones Step 3

Initiates DNA transcription to produce mRNA

Lipid Soluble Hormones Step 4

mRNA move to Ribosomes, then translated into specific protein (proteins have various functions)

Lipid-Soluble Pharmacology

can be taken by mouth, since they can easily cross the intestinal lining and not get damaged in the stomach (steroids and thyroid hormones)

Water-Soluble Pharmacology

get broken down by stomach acid & digestive enzymes that break peptide bonds (ie. why insulin, a protein, must be injected)