Exam 2: Lecture X, Endocrine System Flashcards
Endocrine System Regulates
Homeostasis Long-term Metabolic Processes RBC production Growth and Development Reproduction and differentiation
“Hormone” info
secreted directly into blood stream
Act at long range, and slowly on distant organs and tissues
Anterior Pituitary Gland
- Hypothalamus secretes 7 hypothalamic hormones into portal system (H1)
- APG secretes 7 pituitary hormones (H2)
- Glands of internal secretion release hormones in blood (H3)
Posterior Pituitary Gland
- Hypothalamus secretes 2 hormones through PPG
2. ADH + Oxytocin
Complexity of Endocrine System
- single gland can produce multiple hormones
- single hormone maybe secreted different glands
- single hormone may induce more than 1 type of effect
- rate of hormone may vary considerable
- single target can be effected by more than 1 hormone\
- same messenger maybe hormone or NT
Hormone Secretion can occur in…
Pulses (ie every 15 min)
Constant (steroid secretion)
Rhythms
Hormone Half-life
Seconds, Minutes, Days
Within CNS
Hypothalamus (command center)
Pituitary (Master gland)
Pineal
Endocrine activity regulated by….
Neg/Pos Feedback
Neuroendocrine reflexes
Circadian Rhythms
Endocrine disorders….
Hormone Hypo-/Hyper-secretion
Abnormal Target
Hormone Classes
Peptides
Steroids
Amines (Catecholamines/ Thyroid Hormone)
Peptide Info
Structure: chain of specific amino acids
Solubility: Hydrophilic - water soluble
Transport: Free Hormone
Receptor Site: Surface of target cells
Steroid Info
Structure: Cholesterol Derivative
Solubility: Lipophilic - Lipid soluble
Transport: Mostly bound to plasma protein
Receptor Site: Inside of target cells
From Adrenal Cortex, Gonads, Placenta
Amines (Catecholamines) info
Structure: Tyrosine Derivative
Solubility: Hydrophilic - water soluble
Transport: 50% bound to plasma protein
Receptor Site: surface of target cells
From Adrenal Medulla
Amines (Thyroid Hormone) info
Structure: Iodinated Tyrosine Derivative
Solubility: Lipophilic - Lipid soluble
Transport: Bound to plasma protein
Receptor Site: Inside of target cells
From Thyroid follicular cells
Water Soluble (Peptides/Catecholamines)
dissolved in plasma
cannot pass through lipid membrane
Bind with surface membrane receptors
Lipid Soluble (Steroids/Thyroid hormone)
bound in plasma with plasma proteins
enter cell across the membrane
bind with nuclear receptors -HRE
Growth Hormone (GH, Somatotropin)
stimulates cell growth, body growth
triggers release of somatomedins from liver cells
Thyroid Stimulating Hormone (TSH, thyrotropin)
stimulates growth of thyroid gland
triggers release of thyroid hormone
Adrenocorticotropic Hormone (ADCTH, corticotropin)
stimulates adrenal gland
stimulates glucocorticoids release
Melanocyte-Stimulating Hormone (MSH)
stimulates melanin production
Follicle Stimulating Hormone (FSH, folliculotropin)
stimulates estrogen secretion
stimulates egg development in women
stimulates sperm production in men
Luteinizing Hormone (L.H, Luteotropin)
causes ovulation and progestin production in women
causes testes to secrete test production in men
Prolactin (PRL)
stimulates development mammary glands and milk production
may enhance immune system