Exam 6: Communication, Integration, and Homeostasis

The secretion of the hormone insulin in response to changes in blood glucose level is an example of a(n)________ reflex.

The ________ link membrane receptors to either ion channels or to membrane enzymes located on the cytoplasmic face of the membrane.

Match the term with its description: -the minimum stimulus to trigger a response

Design a flow chart or concept map to summarize the information in the text under the heading "Cell-to-Cell Communication." This chart should make clear the four basic methods of cell-to-cell communication, and the relevance of and distinction between paracrine, autocrine, neurocrine, and cytokine chemicals.

What is the half-life of a signal?

Explain the two forms of down-regulation.

What general action is shared by about half of the medical drugs currently in use?

Inositol triphosphate

When calcium becomes available inside a cell, it comes from

Lipid signal molecules that act in a paracrine fashion and combine with G-protein coupled receptors include ________ and ________.

The most significant difference between a paracrine and an autocrine is

Brain cells are able to absorb glucose independent of insulin.What must be missing from brain cells compared to most other cell types? One of the risks of diabetes mellitus is diabetic coma, which results when insufficient glucose is available to the brain.Would you expect diabetic coma to be triggered when insulin is low or high? Explain.(Hint: Think about regulation of the number of glucose transporters in brain cells and how the hyperglycemia present prior to insulin treatment may affect transporters.)

Asthma is a respiratory disorder characterized by construction of airways and mucus production which makes it very difficult to breathe.The constriction of airways, mucus production, and altered gene expression in the cells lining the airways of asthmatics is due to increased release of neurotransmitter acetylcholine.Explain how a single molecule can have such a large and diverse effect in a single cell.

What is an orphan receptor?

Describe the four classes of membrane receptor molecules.

Many second messenger systems activate ________, enzymes that transfer a phosphate group from ATP to a protein.The phosphorylation of proteins sets off a series of intracellular events that lead to the ultimate cellular response.

The fight-or-flight reaction prepares an animal to respond to a threatening situation, by either fighting or running away.One aspect of this response is changes in blood flow such that the skeletal muscles and heart receive higher blood flow (vessels dilate)while digestive organs receive less (vessels constrict).Which signal molecule(s)is/are involved in this response, and how do they produce these changes in blood vessels? Explain how this example illustrates one or more of the following concepts: multiple ligands for one receptor, multiple receptors for one ligand, agonists and antagonists.

Receptor molecules are located

A physiological parameter which is regulated in an up-down fashion by signals that are always present but change in intensity is said to be under ________.

Cells that respond to signals are usually called