Chapter 5 Flashcards
(20 cards)
Chemical Precursor
Peptide Hormones: Amino Acids (Polypeptides)
Steroid Hormones: Cholesterol names end with -one, -ol, or -oid
Location of Receptor
Peptide Hormones: Extracellular (cell membrane)
Steroid Hormones: Intracellular/Intranuclear
Mechanism of Action
Peptide Hormones: Stimulates receptor (usually G protein-coupled receptor) affecting levels of second messengers (commonly cAMP). Initiates signal cascade
Steroid Hormone: Binds to receptor, induces conformational change, regulates transcription at DNA level
Method of Travel in Bloodstream
Peptide Hormones: Dissolves and travels freely
Steroid Hormones: Binds to carrier protein
Rapidness of Onset
Peptide Hormones: Quick
Steroid Hormones: Slow
Duration of Action
Peptide Hormones: Short-lived
Steroid Hormones: Long-lived
Amino Acid-Derivative Hormones
- Made by modifying amino acids
- Ex: adding iodine to tyrosine (thyroid hormone production)
Direct Hormones
- Secreted into bloodstream
- Travel to target issue where they have direct effects
Tropic Hormones
Cause secretion of another hormone that travels to target tissue to cause an effect
Gonadotropin-releasing Hormone (GnRH)
- Hypothalamic releasing hormone
- Hormone from anterior pituitary: follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
- Target organ: Gonads (testes or ovaries)
- Hormones released by target organ: Testosterone cortical sex hormone (testes) or estrogen and progesterone (ovaries)
Corticotropin-releasing Factor (CRF)
- Hypothalamic releasing hormone
- Hormone from anterior pituitary: Adrenocorticotropic hormone (ACTH)
- Target organ: adrenal cortex
- Hormones released by target organs: Glucocorticoids (cortisol and cortisone)
Thyroid-releasing Hormone (TRH)
- Hypothalamic releasing hormone
- Hormones from anterior pituitary: Thyroid-stimulating hormone (TSH)
- Target organ: thyroid
- Hormones released by target organ: Triiodothryonine (T3) and thyroxine (T4)
Dopamine
- Hypothalamic releasing hormone
- Hormone from anterior pituitary: Prolactin (decrease in dopamine promotes prolactin secretion)
- Target Organ: breast tissue
- No hormones released by target organ
Growth Hormone-releasing Hormone (GHRH)
- Hormone from anterior pituitary: Growth hormone
- Target organ: bone, muscle
- No hormones released by target organ
Calcium Homeostasis
Hormones involved:
1. Calcitonin:
* From parafollicular (C-) cells of thyroid decreases blood calcium concentration
- Parathyroid Hormone:
* From parathyroid glands
* Increases blood calcium concentration
Catecholamines
Synthesized by adrenal medulla
* * Including epinephrine and norepinephrine
Glucose Homeostasis
Pancreatic Hormone Drivers:
1. Glucagon
* From a-cells of pancreas
* Increases blood glucose concentration
- Insulin
* From B-cells of pancreas
* Decreases blood glucose concentration - Somatostatin
* Produced by sigma cells and inhibits insulin and glucagon secretion
* Always inhibitory
Water Homeostasis
Three Hormones Involved:
1. Antidiuretic Hormone (ADH/vasopressin)
* From hypothalamus (released by posterior pituitary
* Increases blood volume
* Decreases blood osmolarity
- Aldosterone:
* From adrenal cortex
* Increases blood volume
* No effect on blood osmolarity
* Mineralcorticoid
* Renin converts plasma protein angiotensinogen > angiotensin I
* Angiotensin I > Angiotensin II by angiotensin-converting enzyme
* Angiotensin II stimulates adrenal cortex to secrete aldosterone - Atrial Natriuretic Peptide (ANP):
* From heart
* Decreases blood volume
* No effect on blood osmolarity
Iodine Deficiency (inflamation of thyroid)
- Can cause hypothyroidism
- In infants can cause cretinism
- Swelling of thyroid gland (goiter)
Peptide Hormone
Hormones that act via second messengers (ex: cAMP) and are relatively large in size (short peptides/complex polypeptides)
* Commonly ends in -in
* Made of chains of amino acids
* Too large, polar, and charged to cross membrane
* Bind to extracellular receptors and rely on second messengers
