L6 Nervous and Endocrine Flashcards
Describe the brain centers
Forebrain
- olfactory
- pineal organ — light sensing
- hypothalamus
- pituitary
Midbrain
- optic
- lateral line
- learning
Hindbrain
- cerebellum (auditory, electro, coordination)
- medulla oblongata (motor-sensory neurons)
- Mauthner cells - escape reflex, direct route from auditory sensing to caudal tail motor neurons
Pituitary Gland
- associated hypothalamus (forebrain)
Hormones: - Adrenocorticotropin : steroid production –> interrenal
- Gonadotrophic H : stimulate gonad function/steroid
- GH: apetite -> growth
- Melanophore : pigment expansion/contraction
- Prolactin: osmotic balance
- Thyrotropin : –> thyroid
Pancreatic Islets
- pyloric ceaca
-metabolism regulation - insulin, glucagon, somatostatin, pancreaspeptide
Ultimobranchial Gland
Calcitonnin: calcium regulation, seawater adaptation
Gastrointestinal Mucosa
Regulate gut motility and secretions
- may secrete glucagon, somatostatin, insulin
Pathway for modifying colouration
The environment displays signal (colour)
- eyes register
– input to brain
— stimulate pituitary
—-MCH : melanophore concentrating hormone
—–plamsa
——mellanophores on non eye side adapt at cellular level
Chromaffin tissue
Adrenaline and noradrenaline (fight/flight)
Interrenal Tissue
-Head of kidney
- Steroids (cortisol) for long term stress response
—- osmoreg (kidney, gill, gastroint)
—-metabolism (protein and carb)
Corpuscle of Stannius
Associated w kidney
- Stanniocalcin (calcium reg - should be present in estuine spp)
—– Removal of tissue results in hypercalcemia
Describe the HPI axis
In stressful social interactions
- Hypothalamus releases CRF: corticotropin releasing factor
—- Pituitary – release (ACTH) adrenocortocotropin
———–Interreneal – release cortisol : fish can deal with stressor
Pineal
Hag fish light receptor
Has function in circadian rhyth (removal disrupts)
may secrete melatonin, seratonin
Thyroid
T4 and T contain iodine
Regulation skin and eye pigments (silvery guanine deposition), metabolism, metamorphosis, osmoreg (salt preference for salmon)
Gonads
Reproductive : androgens and estrogens
Caudal Neurosecretory system
Urotensin 1 and 2 : water balance? sodium regulation?
2 is increased in sucker during spawning
Smoltification
Change colouration, osmoreg (need to change methods) : proton pump moves Na+ into cells in freshwater while chloride cells regulate Cl- removal in salt (Na+ K+ ATPase);
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