Communication & Signaling
This type of communication occurs through gap junctions between two cells of the same type.
Direct Communication
These hormones, such as T4 and Epinephrine, are small molecules structurally related to tyrosine or tryptophan.
Amino Acid Derivatives
The pituitary gland is also known by this name.
Hypophysis
These functional units of the thyroid are lined by simple cuboidal epithelium.
Thyroid Follicles
These pancreatic cells secrete insulin to lower blood glucose levels.
Beta (β) cells
In this signaling mechanism, a cell secretes a chemical messenger that affects itself.
Autocrine Communication
These are chains of amino acids; examples include Insulin and Growth Hormone.
Peptide Hormones
This specific lobe of the pituitary produces ACTH, TSH, and GH.
Anterior Lobe (Adenohypophysis)
This hormone is produced by C cells and helps decrease blood calcium levels.
Calcitonin
This region of the adrenal gland produces Epinephrine and Norepinephrine.
Adrenal Medulla
This highly specialized form of signaling uses neurotransmitters to send high-speed "messages" to very specific, localized destinations across a synapse.
Synaptic Communication
Steroid hormones are lipid derivatives derived from this specific molecule.
Cholesterol
This vascular arrangement allows the hypothalamus to transport regulatory hormones directly to the anterior pituitary.
Hypophyseal Portal System
This hormone is released by principal cells when blood calcium levels drop below 8.5 mg/dL.
Parathyroid Hormone (PTH)
This specific zone of the adrenal cortex is responsible for secreting aldosterone.
Zona Glomerulosa
This enzyme is responsible for converting ATP into the second messenger cAMP.
Adenyl Cyclase (or Adenylyl Cyclase/Adenylate Cyclase)
Because they are bound to specific transport proteins in the plasma, these lipid-derived hormones remain in circulation much longer than secreted peptide hormones.
Steroid Hormones
These two hormones are produced in the hypothalamus but stored and released by the posterior pituitary.
Antidiuretic Hormone (ADH) and Oxytocin (OXT)
About 90% of thyroid secretion is this hormone, which is later converted to the more active T3 in the liver.
Thyroxine (T4)
These hormones from the adrenal cortex (like cortisol) increase glucose and glycogen formation in the liver and provide a "glucose-sparing effect" for the body.
Glucocorticoids
In the IP3-DAG pathway, this enzyme cleaves membrane phospholipids to trigger calcium release.
Phospholipase C (PLC)
These large peptide hormones, such as TSH, LH, and FSH, are distinguished by the presence of carbohydrate side chains.
Glycoproteins
This hypothalamic hormone stimulates the release of FSH and LH from the anterior pituitary.
Gonadotropin-releasing hormone (GnRH)
To increase blood calcium levels, Parathyroid Hormone (PTH) stimulates the activation of these specific bone cells to erode the bone matrix, releasing stored calcium into the bloodstream.
Osteoclasts
This endocrine disorder occurs when the pancreas produces too little insulin, or the body's cells do not respond to it, leading to high blood glucose levels and sugar in the urine.
Diabetes Mellitus