LO1 Endocrine System Flashcards
What method of communication does the endocrine system use?
chemical signaling
Endocrine Glands
Endocrine Gland Hormones ** See Chart 17.2 **
Growth hormone (GH) - Gland/Effect/Chemical Class
- Promotes growth of body tissues
- Anterior Pituitary
- Protein
Peptide Promotes milk production - Gland/Effect/Chemical Class
- Promotes milk production
- Pituitary (anterior)
- Peptide
Thyroid-stimulating hormone (TSH) - Gland/Effect/Chemical Class
- Pituitary (anterior)
- Glycoprotein
- Stimulates thyroid hormone release
Adrenocorticotropic hormone (ACTH) - Gland/Effect/Chemical Class
- Pituitary (anterior)
- Peptide
- Stimulates hormone release by adrenal cortex
Types of Hormones ** See Chart 17.2 **
- Amine Hormone (Norepi)
- Peptide Hormone (Oxytocin)
- Protein Hormone (Growth Hormone)
- Steroid Hormone (Testosterone/Progesterone/Estrogen)
Amine Hormones
Hormones derived from the modification of amino acids are referred to as amine hormones.
Peptide Hormone Example
antidiuretic hormone (ADH), a pituitary hormone important in fluid balance, and atrial-natriuretic peptide, which is produced by the heart and helps to decrease blood pressure.
Protein Hormone
- growth hormone, which is produced by the pituitary gland
- follicle-stimulating hormone (FSH), which has an attached carbohydrate group and is thus classified as a glycoprotein. FSH helps stimulate the maturation of eggs in the ovaries and sperm in the testes.
Steroid Hormone
Estrogen/Testosterone
- Hydrophobic
Pathways of hormone action
- Hormone Receptor
- Target Cell
Pathways Involving Intracellular Hormone Receptors 17.2
Pathways Involving Cell Membrane Hormone Receptors 17.2
Downregulation
allows cells to become less reactive to the excessive hormone levels.
For example, the presence of a significant level of a hormone circulating in the bloodstream can cause its target cells to decrease their number of receptors for that hormone.
Upregulation
When the level of a hormone is chronically reduced, target cells engage in upregulation to increase their number of receptors.
This process allows cells to be more sensitive to the hormone that is present. Cells can also alter the sensitivity of the receptors themselves to various hormones.
The permissive effect
which the presence of one hormone enables another hormone to act.
The synergistic effect
in which two hormones with similar effects produce an amplified response.
The antagonistic effect
in which two hormones have opposing effects.
ex) Insulin and glucagon
Humoral Stimuli
are changes in blood levels of non-hormone chemicals, such as nutrients or ions, which cause the release or inhibition of a hormone to, in turn, maintain homeostasis.
Pituitary Hormones chart 17.3
Anterior Pituitary Hormones and Chemical Class
- Growth Hormone (GH) (Protein) - Promotes growth of body tissues
- Prolactin (PRL) (Peptide) - Promotes milk production from mammary glands
- Thyroid-stimulating hormone (TSH) (Glycoprotein) - Stimulates thyroid hormone release from thyroid
- Adrenocorticotropic hormone (ACTH) (Peptide) - Stimulates hormone release by adrenal cortex
- Follicle-stimulating hormone (FSH) (Glycoprotein) - Stimulates gamete production in gonads
- Luteinizing hormone (LH) (Glycoprotein) - Stimulates androgen production by gonads
Posterior Pituitary Hormones and Chemical Class
- Antidiuretic hormone (ADH) (Peptide) - Stimulates water reabsorption by kidneys
- Oxytocin (Peptide) - Stimulates uterine contractions during childbirth
_____________ signal the posterior pituitary to release antidiuretic hormone (ADH)
osmoreceptors
The target cells of ADH are located in the tubular cells of the _________
Kidneys
Pituitary Gland
Thyroid Gland
Thyroid Hormones
Thyroxine (T4), triiodothyronine (T3) - (Amine) - Stimulate basal metabolic rate
Calcitonin - (Peptide) - Reduces blood Ca2+ levels
Parathyroid Gland
Adrenal Gland
Hormones of the Adrenal Glands
Adrenal gland Associated hormones Chemical class Effect
Adrenal cortex Aldosterone Steroid Increases blood Na+ levels
Adrenal cortex Cortisol, corticosterone, cortisone Steroid Increase blood glucose levels
Adrenal medulla Epinephrine, norepinephrine Amine Stimulate fight-or-flight response
Pineal Gland
Pancreas
Cells and Secretions of the Pancreatic Islets
The pancreatic islets each contain four varieties of cells:
The alpha cell produces the hormone glucagon and makes up approximately 20 percent of each islet. Glucagon plays an important role in blood glucose regulation; low blood glucose levels stimulate its release. The beta cell produces the hormone insulin and makes up approximately 75 percent of each islet. Elevated blood glucose levels stimulate the release of insulin. The delta cell accounts for four percent of the islet cells and secretes the peptide hormone somatostatin. Recall that somatostatin is also released by the hypothalamus (as GHIH), and the stomach and intestines also secrete it. An inhibiting hormone, pancreatic somatostatin inhibits the release of both glucagon and insulin. The PP cell accounts for about one percent of islet cells and secretes the pancreatic polypeptide hormone. It is thought to play a role in appetite, as well as in the regulation of pancreatic exocrine and endocrine secretions. Pancreatic polypeptide released following a meal may reduce further food consumption; however, it is also released in response to fasting.
Glucagon
Insulin
Hormones of the Pancreas
Associated hormones Chemical class Effect
Insulin (beta cells) Protein Reduces blood glucose levels
Glucagon (alpha cells) Protein Increases blood glucose levels
Somatostatin (delta cells) Protein Inhibits insulin and glucagon release
Pancreatic polypeptide (PP cells) Protein Role in appetite
Reproductive Hormones
Gonad Associated hormones Chemical class Effect
Testes Testosterone Steroid Stimulates development of secondary sex characteristics and sperm production
Testes Inhibin Protein Inhibits FSH release from pituitary
Ovaries Estrogens and progesterone Steroid Stimulate development of secondary sex characteristics and prepare the body for childbirth
Placenta Human chorionic gonadotropin Protein Promotes progesterone synthesis during pregnancy and inhibits immune response against fetus
Organs with Secondary Endocrine Functions and Their Major Hormones
Organ Major hormones Effects
Heart Atrial natriuretic peptide (ANP) Reduces blood volume, blood pressure, and Na+ concentration
Gastrointestinal tract Gastrin, secretin, and cholecystokinin Aid digestion of food and buffering of stomach acids
Gastrointestinal tract Glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP-1) Stimulate beta cells of the pancreas to release insulin
Kidneys Renin Stimulates release of aldosterone
Kidneys Calcitriol Aids in the absorption of Ca2+
Kidneys Erythropoietin Triggers the formation of red blood cells in the bone marrow
Skeleton FGF23 Inhibits production of calcitriol and increases phosphate excretion
Skeleton Osteocalcin Increases insulin production
Adipose tissue Leptin Promotes satiety signals in the brain
Adipose tissue Adiponectin Reduces insulin resistance
Skin Cholecalciferol Modified to form vitamin D
Thymus (and other organs) Thymosins Among other things, aids in the development of T lymphocytes of the immune system
Liver Insulin-like growth factor-1 Stimulates bodily growth
Liver Angiotensinogen Raises blood pressure
Liver Thrombopoietin Causes increase in platelets
Liver Hepcidin Blocks release of iron into body fluids
