Endocrinology (hormones)

Cell comm systems- use chem signal

• Nervous (high speed,short term)
• Endocrine (slow,long term)--> relies on horm secretion by endo glands and response by target cells.

Chem signals and target cells

• Target cells respond to chem (neurotrans or horm)
• Target cells possess prot (recept) that bind to neurotrans or horm.
• Bind stim changes in activ (signal transduction)
• Many cells respond to multi chem mess (many spec recep)

Endocrine + nervous syst {related}

• endo glands have neurosecretory cells related to neurons.
• some chem have both nerv and endo func (adrenaline)
• both have + and - feedback (maintain homeo)

Vertebrate endo syst

• Horm secreted by endo glands affect tiss.
• Sex horm eff most cells.
• Tropic horm- eff on other endo glands for coord of physio process.

Hormones

• 4 classes
• Differ in size,chem nature and phys.
• Based on AA or are prot.
• H2O soluble or insoluble.
• Some are lipids.

Chem signalling

• Most horm bind cell surf recep.
• Activate sig transd path.
• Some horm bind nuc recep (steroid).
• Alter gene express pattern.

Endo sig (feedback)

• Digestion- low pH stim secretin release.
• Sig pancreas release HCO3 (raises pH)
• Secretin rel off.

Hypothalamus + pituitary

• Hypo- lower brain.
• Coordinates endo syst.
• Receives info from nerves.
• Resp based on int and ext environ.
• Hypo secretions reg pit gland.
• 2 parts (anterior and posterior)

Posterior gland (neurohypophysis)

• ADH reg kidneys.
• Oxytocin reg fem reprod.
• Horm released to capill of gland.
• Hypo sends sig to pp--> neurosec cells rel neurohorm-->diffuse through blood-->alter targ cell-->resp…