General Introduction Flashcards
Young dogs (2 years or younger) died most commonly of…
Trauma, congenital disease, and infectious causes
Older dogs died overwhelmingly of…
Cancer
Large breeds died more commonly of…
Cancer, musculoskeletal & GI causes
Small dogs died more commonly of…
Endocrine causes & metabolic disorders
What class of hormone does epinephrine, thyroxine & melatonin fall under?
Amino acid derivatives
What class of hormones do hypothalamic hormones/factors fall under?
Peptides
What class of hormones do growth hormones and prolactin fall under?
Proteins
What class of hormones do steroids (i.e., glucocorticoids) fall under?
Cholesterol derivatives
What class of hormones do prostaglandins fall under?
Fatty acid derivatives
Intracrine vs Autocrine
Intracrine - involves blood vessels
Autocrine - secretes into ECF
SC=TC
Juxtacrine vs Paracrine
Juxtacrine - involves blood vessels
Paracrine - secretes into ECF
SC secretes hormone into adjacent/neighbouring cell (TC)
Endocrine
SC secretes hormones via vascular system (bloodstream) into TC
Key differences between protein (peptide) and steroid hormones
Peptides require DNA transcription; steroids do not
Peptides are synthesized in RER and stored in secretory vesicle; steroids are synthesized in SER and mitochondria and diffuse out of cell after synthesis
Modes of secretion
- Phasic (surge; ex. large amounts of insulin, FSH)
- Episodic (pulsatile)
- Circadian, cyclic, circannual (i.e., melatonin, cortisol, thyroid hormone)
- Mixed
How is hormone availability & potency controlled?
- Control of secretion (neuroendocrine reflexes, -/+ feedback)
- Post-translational “processing”
- Storage & transport
- Receptors (types, #’s, distribution, internalization, etc.)
