Bio 365 lec 1

Feedback loops

Physiological mechanisms that regulate processes within normal ranges to maintain homeostasis.

Direct cell signaling

Communication where signaling and target cells are connected by gap junctions.

Gap junctions

Specialized protein complexes with six connexins forming an aqueous pore between adjacent cells.

Paracrine signaling

Short-distance indirect signaling where a chemical messenger diffuses to a nearby cell.

Autocrine signaling

Short-distance indirect signaling where a chemical messenger diffuses back to the signaling cell for self-regulation.

Endocrine system

Long-distance signaling system where hormones are transported by the circulatory system.

Nervous system signaling

Long-distance signaling where electrical signals travel along neurons to release neurotransmitters.

Peptide hormones

Hydrophilic messengers composed of amino acids, stored in vesicles, and bound to transmembrane receptors.

Steroid hormone precursor

Cholesterol, which is converted into various steroid hormones by the smooth ER or mitochondria.

Steroid hormones

Hydrophobic messengers derived from cholesterol that typically have slow effects on gene transcription.

Mineralocorticoids

A class of steroid hormones, such as aldosterone, that regulate electrolyte balance.

Glucocorticoids

Stress hormones like cortisol released by the adrenal cortex.

Amine hormones

Chemical messengers possessing an amine group that are mostly hydrophilic, with the exception of thyroid hormones.

Eicosanoids

Hydrophobic lipid messengers, such as prostaglandins, often involved in inflammation and pain.

Nitric oxide (NO)

A gas messenger that acts as a paracrine to relax and dilate blood vessels.