Endocrine system Flashcards
What are the main endocrine organs
pineal, hypothalamus, pituitary, thyroid, PTH, thymus, pancreas and ovary/testis
What are hormones
chemicals that are released by 1 part of a cell and affect cells in a different body area
——- secreted
Difference between endocrine and Neuroendocrine
Endocrine: secreted into BS
Neuroendocrine: made by neurons + secreted into BS
What does exocrine mean
secreted into a duct which then goes into the BS
- not direct secretion into the BS
T or F: autocrine and paracrine chemicals are hormones
F- work locally not in a different part of body
What is autocrine
chemical that effect the same cell (or type of cell) that secretes it
What is a paracrine chemical
chemical that affect nearby cells; responses to allergens, tissue repair, and blood clotting
T or F: a chemical can be autocrine and paracrine
True
How do hormones work (general)
bind to target cell receptor and alter its activity by…
1) activating secondary messengers
2) direct gene activation (ex// steroid) —- go into cell directly
Effects of hormones on cells (general)
increase PM permeability, change protein synthesis, change enzyme states, stimulate mitosis
Where does hormone specificity come from
come from receptor binding; hormone binds to a specific receptors
- receptors can be found on only 1 cell type or can be on multiple tissues
What impacts receptor and hormone binding/activation
blood hormone levels, number of receptors on target, and affinity of hormone for receptor
—- can upregulate or downregulate receptor amount on target cell in response to hormone-receptor binding
T or F: hydrophobic hormones freely circulate in blood
F —- hydrophobic hormones need to be bound to protein
hydrophilic —- freely circulate
What controls hormone level in the blood
controlled by negative feedback loops
- vary within desired range
- concentration represents the rate of release, speed of inactivation and removal of hormone from the body
What stimulates hormone synthesis/release
1) humoral: ion/nutrient stimulated release; released based on changes in levels (Ex/// Calcium and PTH)
2) Neural: nerve fibers stimulate release (Adrenal medulla — NE + E)
3) Hormonal: release in response to different hormones (tropic — hormones that cause the release/effect other hormones)
Types of interactions of hormones with target cells
1) Permissiveness: 1 hormone doesn’t work without the others (allow each other to work)
2) Synergism: 2 hormones have the same effect
3) Antagonism: work against each other
T or F: The NS can override and take control of the endocrine system (ex// release of hormones —— go outside of normal range)
T
- NS can modify the stimulation of the endocrine glands and their negative feedback loops
—- if we really need something (ex// need more glucose due to stress) : NS can kick in and increase glucose amounts outside of the normal range set by the endocrine organs
T or F: Eicosanoids are true hormones
F - they are autocrine and paracrine
Types of Eicosanoids (general classes)
prostaglandins - inflammation , fever, induce labour, prevent BC
thromboxane - promote BC
leukotrienes - allergic rxn
T or F: Eicosanoids are derived from AA
true —- from AA in PM
- AA produced from alpha-linolenic acid (omega 3) and linoleic acid (omega 6)——— don’t make these
T or F: AA is converted into prostaglandins by LOX enzyme
F - Membrane PL —— AA (by phospholipase) —- PGH2 (COX) —— prostaglandins + thromboxanes
AA——- Leuokotrienes by LOX
What inhibits the COX enzyme
NSAIDS
What specifically inhibits COX2
VIOX — increase CVD risk
Different eicosanoids produced in the prostanoid path and their effects
Prostaglandins- induce labour, vasodilator, pain , pyretic
prostacyclins- inhibit BC, vasodilation
thromboxane - promote BC, vasoconstrictor