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Flashcards in endocrine system Deck (32):
1

allow cells to communicate with each other to regulate body activities
-most are produced by a specific collection of cells or gland

chemical messenger

2

organ consisting of epithelial cells that specialized in secretion

gland

3

controlled release of chemicals from a cell

secretion

4

– secreted in a local area
-stimulates the cell that originally secreted it

autocrine

5

act locally on nearby cells
-secreted by one cell type in ECF and affect surrounding cells

paracrine

6

– secreted by neurons
-activate an adjacent cell, whether neuron, muscle cell or glandular cell
-secreted into synaptic cleft
-can be considered paracrine agents

neurotransmitters

7

– secreted into the bloodstream by certain glands and cells
-affect cells distant from source

endocrine

8

composed of – endocrine glands + endocrine cells (throughout the body)

endocrine system

9

– chemical messengers secreted into bloodstream, not into a duct

hormones

10

types of hormones
– nonpolar
-steroid, thyroid, fatty acid derivative (e.g. eicosanoids)

Lipid-soluble hormones

11

type of hormone
– polar
-protein, peptide, most amino acid derivative

water soluble hormones

12

• Circulate as free hormones (dissolve directly into blood and delivered to target tissue w/o attaching to binding proteins) because they can dissolve in blood

water soluble hormones

13

• Tend to diffuse from the walls of the capillaries more slowly (because they are big)

water soluble hormones

14

• Capillaries regulated by these hormones are usually fenestrated or very porous

water soluble hormones particularly protein

15

type of hormone that • Have short half-lives

water soluble

16

• Travel in the bloodstream attached to binding proteins (because they are small and low solubility in aqueous fluids, this prevents them from being degraded or eliminated)

lipid soluble hormones

17

hormones from the anterior pituitary gland

tropic hormones

18

type of control of hormonal release
• These hormones are sensitive to blood levels of a particular substance
occurs when there are bloodborne molecules that can directly stimulate the release of some hormones

Humoral stimuli

19

type of control of hormonal release
occurs when neurons release a neurotransmitter into the synapse with the cells that produce the hormone

control by neural stimuli

20

– hormones that are secreted by neurons directly into the blood when they are stimulated

neuropeptides

21

– neuropeptides that stimulate hormone secretion from other endocrine cells
-usually for hormones from hypothalamus

releasing hormones

22

occurs when a hormone is secreted and in turn stimulates the secretion of other hormones

control by hormonal stimuli

23

type of regulation of hormones
– regulates most hormones
-hormone’s secretion is inhibited by the hormone itself once blood levels have reached a certain point and there is adequate hormone to activate the target cell (self-limiting system)

negative feedback

24

type of regulation of hormones
some hormones, when stimulated by a tropic hormone, promote the synthesis and secretion of the tropic hormone in addition to stimulating their target cell (self-propagation system)

positive feedback

25

proteins where hormones bind to exert their actions

receptors

26

portion of each receptor molecule where a hormone binds

receptor site

27

tendency for each type of hormone to bind to one type of receptor

specificity

28

class of receptor
where lipid soluble hormones bind (because they are small and can diffuse into the plasma membrane)
-found in cell nucleus or in the cytoplasm (but move to nucleus when activated)
-hormone-receptor complex interacts with DNA in the nucleus or w/ cellular enzymes to regulate the transcription of particular genes in the target tissue

nuclear

29

class of receptor
where water soluble hormones bind (because they are big and cannot diffuse into PM)
-proteins that extend across the plasma membrane’s outer surface
-hormone-receptor complex initiates a response inside the cell

membrane-bound

30

MBR activate responses in 2 ways:

1. Altering the activity of G proteins at the inner surface of PM
2. Directly altering the activity of intracellular enzymes

31

chemical produced inside a cell once a hormone or another chemical messenger binds to certain MBR, which then activates specific cellular processes
-some are second messengers
-second-messenger system

intracellular mediator

32

happens wheneach receptor produces thousands of second messengers
-a single hormone activates many second messengers, each of which activates enzymes that produce an enormous amout of final product

signal amplification

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