Swineburn W1

homeostasis

essential for health and survival

negative feedback

• stabilizes a process, or can turn it off

• maintaining physiological variables within a tight range despite internal/external challenges.

negative feedback

stabalizes a process or can turn it off

feed forward controls

organs prepare

endocrine system

an anatomically distributed but functionally connected system that serves as one of the body’s two control systems

hormones

chemical messengers that are released into the bloodstream from the site of secretion to reach their site of action, serum levels low, nano molar and picomolar

endocrine glands

ductless glands producing hormones (pituatary, thyroid, adrenal, pancreas, gonads, hypothalamus)

non-glandular hormone secreting cells

heart, liver, stomach, brain

endocrine cell-cell signaling

hormones act on distance targets via blood

paracrine cell-cell signaling

local action of neighboring cells

autocrine cell-cell signaling

local action on neighboring cells

synaptic cell-cell signaling

neurotransmitters at cell junctions

biogenic amines

tyrosine derivatives

• catecholamines

• thyroid hormones

major tissue sources of biogenic amines

hypothalamus, adrenal medulla, thyroid gland

catecholamines

water soluble, released via SNARE- mediated

• norepinephrine

• epinephrine

thyroid hormones

iodine-containing derivatives produced from a complex biosynthetic cascade

thyroid hormone synthesis

synthesized in the thyroid gland through a complex mechanism involving massive extracellular colloid particle

peptide/protein hormones

largest class, processed fro preprohormones, water-soluble

• insulin

biosynthesis of peptide/protein hormone

• ribosomes of the rough the ER translte prehormones

• ER enzymes cleave to prohoromones

• Prohoromones post-translationally modified and packaged into secretory vesicles in the Golgi

steroid hormones

cholesterol derivatives, lipid soluble

• cortisol

• aldosterone

• sex steroid

biosynthesis of steroid hormone

• hormones are controlled at the level of biosynthesis rather than secretion

• relative expression of biosynthetic enzymes in a given cell-type determines which hormone is secreted

adenoma

benign tumor of glandular orgin

paraneoplastic syndrome

set of symptoms caused by the chemical produced by a tumor, can be a non-endocrine tumor

parasympathetic roles

increases secretion and motility

sympathetic roles

decreases secretion and motility, reduces blood flow

ENS sensory neurons

monitor luminal activity = distention, pH, osmolarity, nutrients, mechanical stimulation

ENS activation

promote or inhibit smooth muscle contraction, epithelial cell secretions, endocrine hormone production, submucosal bloos vessel behvaior