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Ch 6 Communication, Integration, and Homeostasis

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Targets
Cells that respond to signals are usually called
Mechanical signals
Which is NOT a basic method of cell to cell communication?
Cytoplasmic transfer of signals
Contact dependent signals
Nerve and blood transport signals
Mechanical signals
The cell that responds to it
The most significant difference between a paracrine and an autocrine is
Are released by neurons and affect only cells with specific receptors
Neurotransmitters and neurohormones both
Some cells lack the necessary receptors
Why do some normal cells fail to respond to a chemical signal?
Determine that cells response and may allow a particular ligand to bind
Receptor molecules on the surface of a cell
In all these places: outer cell membrane, cytosol, nucleus, cell surface
Receptor molecules are located
Only decrease its number of receptors for a ligand
Down- regulation may allow a target cell to
Is a second messenger that is involved in the release of calcium into the cytosol
Inositol triphosphate
Bind to receptors inside the cytoplasm or nucleus
Lipophilic hormones
cAMP is formed
When adenylyl cyclase is activated
ALL OF THE ANSWERS
Second messenger molecules directly
Protein kinase A
Cyclic AMP activates
Phosphatidylinositol bisphosphate
Diacylglycerol is produced from
JAK kinase
Usually, cytokine binding activates
Citrulline
What by product results during the production of nitric oxide
Evaluates incoming signals and compares it with the setpoint
An integrating center
ALL: specificity, nature of the signal, speed, duration of action
Which of the following are considered differences between endocrine and neural control systems
Setpoint
The desired target value for a parameter
Integrating center
Receives information about the regulated variable and initiates a response
Threshold
The minimum stimulus to trigger a response
Effector
The organ or gland that performs the change
Sensory receptor
Continuously monitors its environment for a specific variable
Targets
Peripheal calls sensitive to the presence of hormones
Nitric oxide, carbon monoxide, hydrogen sulfide
A few gases are known to act as signal molecules, including
Endothelial cells, endothelial derived relaxing factor
Before nitric oxide was identified, its action was observed in ___ and it was given the name ___
Diseases
Can be caused by alterations in receptors or by problems with G protein or second messenger pathways
Eicosanoids, sphingolipids
Lipids signal molecules that act in a paracrine fashion and combine with G protein coupled receptors include
Signal transduction, first messenger, second messenger
__ is a process by which an extracellular signal molecule, called the ___, activates a membrane receptor that in turn alters intracellular molecules, called the __, to create a response
Connexins
A gap junction forms when opposing membrane spanning proteins called __ on two adjacent cells unite, creating a protein channel that is capable of opening and closing
Paracrine
A chemical that is secreted by a cell to act on cells in its immediate vicinity is called a
Autocrine
If the signal molecule acts on the cell that secreted it, the chemical is called an
Neurocrines
All molecules secreted by nerve cells are called
Antagonists
___ are molecules that bind to the receptor in such a way that they block the normal ligand from binding and turning the receptor on. As a result, the signal pathway remains inactive
Up regulation
If the concentration of an endocrine ligand decreases, the target cell may insert more receptors into the cell membrane in an attempt to keep its response at a normal level, in a process known as
Internal Environment
The nervous system has a role in preserving the "fitness" of the
G proteins
The ___ link membrane receptors to either ion channels or to membrane enzymes located on the cytoplasmic face of the membrane
Protein kinases
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.
Homeostasis
To maintain ___, the body uses a combination of simple diffusion across small distances; wide spread distribution of molecules through the circullatory system and rapid, specific delievery of messages by the nervous system
Nervous, endocrine
Most long distance communication between cells takes place through the ___ and ___ systems with their combination of chemical and electrical signals
Second messenger
An intracellular signal molecule that translates a signal from a neurotransmitter or hormone into an intracellular response is called a
Simple endocrine
The secretion of the hormone insulin in response to changes in blood glucose level s an example of a __ reflex
Receptor, effector
Homeostatic regulation usually involves a ___ that is sensitive to a particular stimulus and an ___ whose activity has an effect on the same stimulus
Constric, dilate
When epinephrine combines with alpha adrenergic receptors on smooth muscle in intestinal blood vessels, the blood vessels ___; however when epinephrine binds to beta-2 adrenergic receptors on certain skeletal muscle blood vessels, the vessels ___
Half life of a signal
The time required for a signal to lose half its activity
Orphan receptor
A receptor that has no known ligand
Protein Kinase
The intracellular effector in chemical signaling is often
The lipid solubility of the ligand
The most important factor determining which type of receptor a signal molecule will bind to is
Calcium
An ion widely important in intracellular signaling is
Extracellular fluid and intracellular storage
When calcium becomes available inside a cell, it comes from
Calmodulin
One intracellular calcium binding protein is
Specificity, competition, and saturation
Signal molecule receptors exhibit
Gene transcription
The binding of lipophilic messengers, such as steroid hormones, to their receptors triggers
The two hormones bind to different receptors and use a different second messenger
Both insulin and glucagon are peptide hormones that target liver cells. The response of the target cells to each of these two hormones is opposite. This information implies that
Local control
Homeostatic control that takes place at the tissue or cell by using paracrine or autocrine signals is called ___
Tonic control
A phisiological parameter which is regulated in an up down fashion by signals that are always present but change in intensity is said to be under