Chapter 5 Lecture Slides Flashcards
what are the four basic methods of cell-to-cell communication that our bodies use, and are they local or long-distance? (5)
- gap junctions (local)
- contact-dependent signaling (local)
- autocrine and paracrine (local)
- endocrine uses hormones (long-distance)
- signaling pathways (long distance)
what is autocrine signaling?
source = target
source = target ?
autocrine signaling
what is paracrine signaling?
source does not equal target, but immediate vicinity
signal is secreted into the interstitial fluid and diffuses to nearby cells in the same tissue
paracrine
what is an example of paracrine signaling?
endothelial cells of the vascular system talk to neighboring tissue cells
where is the signal secreted in paracrine signaling? what happens next?
into the ISF and diffuses to nearby cells in the same tissue
redding at a scratch is due to release of?
paracrine molecule histamine
how does the endocrine system communicate?
hormones
hormones are used by ?
endocrine system
describe endocrine signaling?
source isn’t the target, far away
hormones are… (2)
- chemical messengers made by gland cells
- secreted into the bloodstream to act on target cells in another tissue or organ
how does the nervous system communicate?
combo of electrical and chemical signals
what provides the specificity in a signaling pathway?
receptors
where may the receptor be located, depending on the ligand?
on or in the target cell
steroid hormones: hydrophilic or hydrophobic?
hydrophobic
steroid hormones: lipophilic or lipophobic?
lipophilic
how are steroid hormones made?
from cholesterol and on demand
how are steroid-based hormones transported in the blood?
bound to carrier proteins
why do steroid-based hormones have to be bound to a carrier protein while in circulation?
because they are hydrophobic!
what does amphipathic mean?
hydrophilic and hydrophobic side
steroid hormones bind to receptors where? why? (2)
- in the cytoplasm. they are lipophilic/hydrophobic
- bind to HREs
what are HREs?
hormone responsive elements. DNA sequences that, when bound by their specific ligand/receptor complex, turn gene expression on or up
are lipophilic hormones fast acting?
no. they use intracellular receptors that initiate gene transcription to make mRNA
