The Endocrine System Flashcards
The Endocrine System
Organ system that controls the body using chemical messengers called hormones
Major Processes Regulated By the Endocrine System
- Reproduction (estrogen (in females)), testosterone (in males))
- Growth + Development (growth hormone, thyroid hormone)
- Mobilization of Body Defenses (thymic hormone)
- Electrolyte + Water Balance (ADH, ANP, Aldosterone)5. Regulation of Cellular Metabolism + Energy Balance (insulin, glucagon)
Major Endocrine Glands
- Pineal Gland
- Hypothalamus
- Pituitary Gland
- Thyroid Gland
- Parathyroid Gland
- Thymus Gland
- Adrenal Gland
- Pancreas
- Ovary
- Testes
Other Hormone Producing Structures and what they produce
- Adipose Cells: produces Leptin
- Mucosa of Digestive System: produces Gastrin, Secretin
- Kidneys: produces Erythropoietin (make RBCs)
- Heart: produces atrial natriuretic peptide (ANP)
- Skin: produces Vitamin D
- Placenta: produces hCG (indicates pregnancy), Progesterone + Estrogen (keep pregnancy going), Prostaglandins (helps push baby out)
Other Hormone Producing Structures
- Adipose Cells
- Mucosa of Digestive System
- Kidneys
- Heart
- Skin
- Placenta
Circulating Hormones
carried by blood, act on distant target cells
- Endocrine Glands:
- are ductless
- secrete into interstitial fluid (IF)
Local Hormones
do not circulate in blood
- Paracrines- local hormones acting as neighboring cells
- Autocrines- local hormones acting on own cells
Chemical Classes of Hormones
- Lipid- Soluble= steroids + thyroid hormone
2. Water- Soluble= amines, peptides/proteins, and eicosanoids
Chemical Classes of Hormones: Water- Soluble Hormones
Can dissolve in water
- Amines- modified amino acid (epinephrine, norepinephrine)
- Peptide- less than 50 amino acids (ANP)
- Protein- (Insulin, Growth Hormone)
- both chain of amino acids - Eicosanoids- modified fatty acid (arachidonic acid)
- most act as local hormones
Chemical Classes of Hormones: Lipid- Soluble Hormones
Can dissolve in lipids (fats)
- Steroids- estrogen, testosterone
- modified from cholesterol - Thyroid Hormone- contain iodine’s
Mechanisms of Hormone Action
- Lipid-soluble hormones use Direct Gene Activation
2. Water-soluble hormones use Second Messenger Activation
Direct Gene Activation by Lipid-soluble hormones
- Hormone diffuses through plasma membrane
- Binds to intracellular receptor
- Transcription of specific gene
- New protein is made by cell (translation)
Second Messenger Activation by Water-soluble hormones
- Hormone (1st messenger) binds to receptor on cell surface
- This causes a 2nd messenger to be made inside the cell
- 2nd messenger activates protein kinase
- Protein kinase activates a protein
An example of a 2nd messenger is
cyclic AMP (cAMP)
What causes Endocrine Glands to secrete hormones?
- Humoral Stimulus
- Neural Stimulus
- Hormonal Stimulus
What causes Endocrine Glands to secrete hormones?
Humoral Stimulus
gland responds to change in chemical composition of blood
ex: increase Ca+2 –> thyroid gland releases calcitonin –> decreases Ca+2
ex: decrease Ca+2 –> thyroid gland release parathyroid –> increase Ca+2
What causes Endocrine Glands to secrete hormones?
Neural Stimulus
gland responds to Nervous System
ex: sympathetic division (fight or flight) –> adrenal medulla will release epinephrine + norepinephrine
What causes Endocrine Glands to secrete hormones?
Hormonal Stimulus
gland responds to a hormone
(1st endocrine gland stimulates hormone secretion from 2nd endocrine gland)
ex: adrenal cortex is hormonally stimulated by one of the pituitary hormones
Hypothalamus makes what kind of hormones?
Water-soluble
Pituitary Gland makes what kind of hormones?
Water-soluble
tract
branch of axons
What is the Hypophysis?
the Pituitary Gland
Neurohypophysis
posterior pituitary and infundibulum
-the hypothalamic-hypophyseal tract is the neural connection between hypothalamus and posterior pituitary
Hypothalamic- hypophyseal tract
the neural connection between hypothalamus and posterior pituitary
