Intro to Endocrine Flashcards
What is the goal of the endocrine system?
Homeostatic regulation of physiological processes through coordinated function of the endocrine and autonomic nervous system. Critical for metabolism, reproduction, and growth. Has behavioral components
What coordinates components of the endocrine system?
Hypothalamus
What does endocrine mean?
Secrete internally, usually into systemic circulation
What is a hormone?
Chemical substance produced by a gland or tissue that acts upon distant targets at low concentrations. Targets must have receptors
What are the functions of a hormone?
- Reproduction and sexual differentiation
- Development and growth
- Maintenance of the internal environment
- Regulation of metabolism and nutrient supply
What is a permissive effect?
One hormone may have an effect on another hormone. to reach it’s physiological max
How do you get integrated activity of the endocrine and nervous system?
- Endocrine reflex loop
- Autonomic reflex loop
- Regulatory behavior
What is the endocrine reflex loop?
- Stimulus from afferent nerves
- Central integration (hypothalamus)
- Release hormone
- Hormone action upon target
- generally negative feedback loop
What are the types of hormones?
- Metabolism
- Growth
- Reproduction
What are the types of metabolism hormones?
- M-energy
- M-Mineral
What are the M-energy hormones?
Insulin, glucagon, cortisol, epinephrine, thyroid hormone, growth hormone
What are the M-mineral hormones?
Parathyroid hormone, calcitonin, angiotensin, renin, aldosterone
What are the growth hormones?
Growth hormone, thyroid hormone, insulin, estrogen, androgens, Growth factors
What are reproduction hormones?
-Estrogen, androgen, progesterone, LH, Follicle-stimulating hormone, prolactin, oxytocin
What are the different chemical composition of hormones?
- Proteins
- Peptides
- Amines
- Thyroid hormone
- Steroids
Which hormones are proteins?
- Growth hormone
- Insulin
- Corticotropin
How are protein hormones made?
Synthesized as prehormones and modified to prohormones. They are stored within granules in the gland until released via exocytosis
Which hormones are peptides?
- oxytocin
- Vasopressin
- Angiotensin II
- Cholecystokinin
Which hormones are amines?
- Dopamine
- Nor/Epinephrine
- Melatonin
Which hormones are steroids?
- Adrenocortical
- Sex hormones
How are steroid hormones made?
Synthesized from cholesterol in the liver and they are released as they are made
What percentage of hormones are proteins and peptides?
85%
Where are protein receptors?
Cell membrane. Proteins are water soluble so they don’t cross the membrane
Why can’t you administer peptide hormones orally?
They are easily digested and inactivated by gastrointestinal enzymes
What percentage of hormones are steroid hormones?
15%
Where are steroid hormone receptors?
Cytoplasmic receptors. Steroids have hormone-receptor complex traffic to nucleus
Can you administer steroid hormones orally?
Yes
Amino acid and fatty acid derived hormones are derived from what?
Tyrosine or tryptophan
The adrenal medulla produces?
Catecholamines (Nor/Epinephrine)
What produces melatonin?
Pineal gland
What is an intracrine system?
Goes within cell, not a hormone, usually second messenger signaling
What is the paracrine system?
Released and goes to neighboring cell. If it enters blood cell ->local hormone