Module 12: Endocrine System Flashcards
(18 cards)
Gap Junctions
a. Chemical mediator used:
b. Distribution of effects:
Paracrines
a. Method of signal transmission:
b. Distribution of effects:
Hormones
a. Method of signal transmission:
b. Distribution of effects:
Neurotransmitters
a. Method of signal transmission:
b. Distribution of effects:
Endocrinology
involves the diagnosis and treatment of endocrine system disorders
Endocrine glands
pituary, thyroid, adrenal glands and pancreas: multicellular glands producing hormone
There are other organs and tissues that produce hormones
adipose tissue produces leptin hormone; looking more globally
Target organs and target cells
whose functions are altered in response to a hormone
Nervous System
a. Communicate using neurotransmitters and action potentials
b. Act at synapses on target cells
c. Local, specific effects
d. Act within milliseconds
e. Stops quickly when stimulus stops
f. Adapts quickly
g. Short term stresses
h. Targets are muscles, glands, adipose tissue, neurons
Endocrine System
a. Communicate using hormones released into blood
b. Act on targets far from site of release
c. General, widespread effects
d. Act within seconds to days
e. Continues to respond long after stimulus stops
f. Adapts relatively slowly
g. Long term stresses
h. Targets are body cells
Monoamines (biogenic amines)
a. Produced from amino acids
i. Tyrosine
ii. Tryptophan
Peptide hormones
a. Chains of amino acids
i. Oligopeptides
ii. Polypeptides
iii. Glycoproteins
Steriod hormones
a. Made from cholesterol
Hydrophilic hormones freely circulate in blood
a. Effects are short-lived because
i. Diffuses out of blood and binds to receptors
ii. Filtered out at the kidney
iii. Broken down by enzymes in IF, plasma, liver, & kidney
Hydrophobic hormones must bind to transport proteins (albumins and globulins)
a. Bound hormone
b. Unbound hormone
c. Transport protein binding allows for longer hormone half-life
i. Provide protection from enzymes in plasma, liver, & kidney
ii. Prevent filtration at kidney
d. Bound hormone acts as hormone reserve
i. Replenishes free fraction
Hormone receptors
a. Cells have receptors for many hormones
i. Specificity
ii. Saturation
b. Cells have different combinations of receptors
c. Cells must have the correct receptor to be affected by a hormone
Plasma membrane receptors
a. Used by:
b. Mechanism of action:
i. Formation of a First Messenger
ii. Formation of a Second Messenger
c. Effects on the cell:
i. Phosphorylation of existing enzymes or increasing calcium concentrations
d. Signal amplification allows one hormone molecule to trigger the synthesis of an
enormous number of enzymes
e. Receptor number can change to adjust target cell sensitivity
i. Down-regulation
ii. Up-regulation
Intercellular Receptors
a. Diffusion of hormones across plasma membrane
b. Bind to receptors in cytoplasm or nucleus
c. Effect on the cell:
i. Activate or deactivate specific genes
ii. Increase rates of mitochondrial activity
d. It takes hours to days to show an effect
