Cell Communication

What is paracrine signaling?

Signaling that moves by diffusion through the extracellular matrix, examples include synaptic signals and neurotransmitters.

What is endocrine signaling?

Signals from distant cells that typically produce a slower response with a long-lasting effect, such as hormones.

What is autocrine signaling?

Signaling where the signaling cells can also bind to the ligand they release, meaning the signal and target cell can be the same.

What is direct signaling across gap junctions?

A form of signaling that allows intracellular mediators to move small signaling molecules between cells.

What role does acetylcholine play in the body?

It controls skeletal muscles and may function in the sleep-wake cycle, learning, memory, and mood.

What is the effect of botulinus toxin?

It acts as an antagonist by binding to presynaptic neurons and preventing acetylcholine release, causing muscle paralysis.

What is the effect of black widow spider venom?

It acts as an agonist, increasing the release of acetylcholine and causing muscle cramps and spasms.

How do organophosphorus insecticides affect the nervous system?

They block the action of acetylcholinesterase, leading to overstimulated nerves, muscle contraction/weakness, and convulsions.

What is the function of antihistamines?

They block histamine receptors to alleviate symptoms of allergic reactions.

What are the three main classes of hormones?

Amino acid derivatives, polypeptides, and steroids.

How do steroid hormones function?

They can enter the cell directly because they are hydrophobic and nonpolar.

What is the role of polypeptide and amino acid derivative hormones?

They are water-soluble and deliver messages by binding to receptors on the cell surface, releasing a second messenger.

What is the function of thyroxine?

It is an iodine-containing hormone produced by the thyroid gland, which can cause goiter when iodine is low.

What triggers the release of epinephrine?

It is released from adrenal glands in response to danger, increasing glucose availability for energy.

What is signal transduction?

The process by which a ligand binds to a receptor and transmits the signal through the cell membrane into the cytoplasm.

What is dimerization in cell signaling?

The process where two receptors bind to each other to form a stable complex.

What is the epidermal growth factor (EGF) receptor (EGFR)?

A receptor tyrosine kinase involved in regulating cell growth, wound healing, and tissue repair.

What is apoptosis?

A form of programmed cell death that can be induced by cell signaling.

What is quorum sensing in bacteria?

A signaling mechanism that utilizes autoinducers to communicate based on population density.

What is the role of growth factors in cell signaling?

They bind to tyrosine kinases, initiating pathways that lead to cell division.

What is the function of histamine in the body?

It is a neurotransmitter responsible for allergic reaction symptoms and causes the release of stomach acid.

What is the role of the hypothalamus in hormone regulation?

It controls the release of hormones directly or indirectly through the pituitary gland.

What is the function of insulin?

A hormone released by the pancreas to stimulate glucose uptake.

What is the significance of the signaling pathway?

It is a chain of events including second messengers, enzymes, and activated proteins that follow ligand binding to a receptor.

What happens when EGFR is activated inappropriately?

It may lead to uncontrolled cell growth, which can result in cancer.

What is the role of phosphatases in cell signaling?

They terminate signals by removing phosphate groups attached to proteins by kinases.