The Biology Project > Cell Biology > Cell Signaling > Problem Set

Cell Signaling Problem Set

Problem 4: Kinds of Signals

Tutorial to help answer the question

A cell secretes growth factors that have a slow diffusion rate, and interacting only with other cells in the immediate area is an example of _______________ signaling.

A.	exocrine
B.	synaptic
C.	paracrine
D.	cell contact

Tutorial

Types of signaling

Autocrine signals bind to receptors on cells that secrete them.

Paracrine signals bind to receptors and stimulate nearby cells.

Exocrine signaling occurs when cells secrete signaling molecules into the blood. For example, the ovaries in females and the testes in males are stimulated by hormones produced by the brain.

Synaptic signaling is similar to paracrine signaling but there is a special structure called the synapse between the cell originating and the cell receiving the signal. Synaptic signaling only occurs between cells with the synapse; for example between a neuron and the muscle that is controlled by neural activity.

Signaling by cell contact must have cells with adjacent plasma membranes. Later you will learn that cells are altered by their immediate environment and by signaling molecules from other cells.

The Biology Project > Cell Biology > Cell Signaling > Problem Set