Physiology Exam 1 Study Chapter 6 Communication & homeostasis

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Physiology Exam 1 Study

Chapter 6 Communication & homeostasis

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What are the two basic physiological signals?

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-Chemical -Electrical

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What are the basic methods of cell-cell communication?

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- Direct cytoplasmic transfer- Gap junctions- Contact-dependent signals- Local communication- Long distance communication

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Which method of cell-to-cell communication occurs by chemicals that diffuse through the extracellular fluid?

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-Local Communication

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This method of cell-to-cell communication involves the transfer of chemical and electrical signals between adjacent cells.

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-Gap junctions

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Where would you expect to find Gap Junctions in the body?

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-Heart-Smooth muscle of the GI tract

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What are the cells that receive electrical or chemical signals called?

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-Target Cells

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What is the simplest form of cell-to-cell communication?

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-Gap junctions

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A gap junction forms from the union of membrane-spanning proteins called____.

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-Connexon

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When do connected cells function like a synctium?

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-When the gap junction (connexon) is open.

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What is the only means by which electrical signals can pass directly from cell to cell?

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-Gap junctions

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What method of cell-to-cell communication utilize Cell Adhesion Molecules (CAMs) to transfer signals?

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-Contact Dependent

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How is local cell-to-cell communication accomplished?

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-Paracrine signaling-Autocrine signaling

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If a chemical signal acts on the cell that secreted it, it is called an _____ signal.

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-Autocrine

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If a chemical acts on cells in the immediate vicinity of the cell that secreted it, its is called ____ signal.

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-Paracrine

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If a cell secretes chemicals that act on distal cells it is a ____ signal.

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-Endocrine

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What is secreted by neurons to act on itself or neighboring cells?

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-Neuromodulators

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What are regulatory substances that mediate immune responses?

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-Cytokines

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Why are paracrine and autocrine signals only able to reach adjacent cells?

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-Because both of these signals reach their targets by diffusing through the interstitial fluid. Diffusion is limited by distance.

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Most long-distance communication between cells is the responsibility of what two organ systems?

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-Nervous system-Endocrine system

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An electrical signal travels along a ___ until it reaches the very end of the cell, where it is translated into a ____ .

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Neuron,Neurocrine

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If a neurocrine diffuses into the blood it is called a ____.

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Neurohormone

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If a neurocrine acts more slowly as an autocrine or paracrine signal, it is called a ______.

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Neuromodulator

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If a neurocrine has a rapid effect it is called a _____.

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Neurotransmitter

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What are Cytokines?

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Cytokines are regulatory peptides that act close to the site where they secreted.

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True or False? Cytokines are stored much like hormones?

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False(Cytokines are produced on demand.)

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True or False? A cytokine can act as an autocrine and a paracrine.

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-True

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Where are receptor proteins located?

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-Cytosol-Cell membrane-Nucleus

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This type of receptor mimics the effect of the naturally occuring ligand?

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-Agonist

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Which signal molecule is unable to enter the cell?

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-Lipophobic

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What are the four classes of membrane receptors?

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- Ligand-gated ion channels- Intergrin linked to cytoskeleton- G protein-coupled receptor with

seven membrane- Receptor Enzyme

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What is the result of a ligand binding to a ligand gated channel?

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-Channel opens or closes

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Which type of regulation results in the reduction in the number of receptors and/or binding affinity for the ligand?

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Down-regulation

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What is the result of a ligand binding to a G protein coupled receptor?

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-The G-protein receptor opens an ion channel or alters enzyme activity

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Which membrane receptor results in the activation of an intracellular enzyme?

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-Enzyme receptor

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Which membrane receptor result in a change to the cytoskeleton?

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-Intergrin

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Which of the four categories of membrane receptors do NOT use signal transduction?

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-Ligand gated

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Where are receptor proteins located?

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-Inside the cell or -On the cell membrane

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Chemical signals fall into what two broad categories?

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-Lipophillic-Lipophobic

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Where would you find Target cell receptors?

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-Nucleus-Cytosol-On the cell membrane

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If you find target cell receptors on the cell membrane, they are likely to be what type protiens?

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-Intergral proteins

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The location where a chemical signal binds to its receptor largely depends on what?

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-Whether the signal molecule can enter the cell

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About half of all drugs currently in use act on?

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-Receptors proteins

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What is signal transduction?

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- The process by which an extracellular signal molecule activates a membrane receptor that in turn alters intracellular molecules to create a response.

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What is a transducer?

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-A device that convets a signal from one form into a different form.

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What turns a signal molecule into multiple second messengers?

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-Signal amplification

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What is the function of an amplifier enzyme?

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-An enzyme that activates several more molecules.

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Place the following words in correct order of signal transduction:* RESPONSE * RECEPTOR* AMPLIFIER* TRANSDUCER* EXTERNAL SIGNAL

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What is protein kinase?

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-Enzymes that transfer a phosphate group from ATP to a protein.

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What two things can an activated membrane receptor do after it turns on its associated proteins?

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-Activate protein kinase-Activate amplifier enzymes

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What is protein kinase?

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-Enzymes that transfer a phosphate group from ATP to a protein.

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Once created by amplifier enzymes, second messeger molecules do what three things?

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-Alter gating channels-Increase intracellular calcium-Change enzyme activity

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What are the three most common amplifier enzymes?

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-Adenylyl cyclase-Guanylyl cyclase-Phospolipase C

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Where is the amplifier enzyme Adenylyl cyclase located?

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-Membrane.

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What activates Adenylyl cyclase?

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-G protein-coupled receptor

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Where is the amplifier enzyme Guanylyl cyclase located?

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-Membrane-Cytosol

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What activates Guanylyl cyclase?

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-Receptor enzyme Nitric Oxide (NO)

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What are the three categories of second messengers?

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-Nucleotides-Ions-Lipid-derived

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Memorize

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Which second messenger is causes exocytosis, muscle contraction, cytoskeleton movement, channel opening?

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-Ca2+

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Ca2+ Binds to what?

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-Calmodulin and other proteins

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Name the two second messengers that fall under nucleotides

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-cAMP-cGMP

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Which second messengers activates protein kinase A, G, C?

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- cAMP activates protein kinase A - cGMP activates protein kinase G - DAG activates protien kinase C

(there is a C in DAG, Diacylglycerol)

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Which second messenger releases calcium from intracellular stores?

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-IP3

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Which second messenger(s) effects phosphorylates and alters channel opening?

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Both cAMP & cGMP

(nucleotides)

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What are the steps of signal transduction?

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1. Signal molecule binds to receptor that

2. Activates a protein that3. Creates second messengers

that4. Creates a response

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Name the two regions of receptor enzymes and there locations?

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1. Receptor region; extracellular side of cell membrane

2. Enzyme region; on the cytoplasmic side

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Where are ligand-gated ion channels most often located?

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Excitable tissues of nerve and muscle

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Where are most intracellular Calcium ions stored?

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Endoplasmic reticulum

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What 5 properties are used to compare Neural and Endocrine Control?

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1. Specificity2. Speed3. Duration of action4. Coding for stimulus

intensity5. Nature of signal

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Memorize

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The duration of action of this type of reflex is usually very short?

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Neural Reflex

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What mediates a longer duration of action for a neural reflex?

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Neuromodulators

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Chemical signals are secreted in the blood for distribution throughout the body by this type of reflex?

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Endocrine Reflex

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The response to this type of reflex depends on which cells have receptors for the hormone?

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Endocrine Reflex

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Each signal is identical in strength pertaining to this type of reflex?

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Neural Reflex

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This type of reflex coding for stimulus intensity is correlated with the amount released?

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Endocrine Reflex

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This type of reflex coding for stimulus intensity is correlated with frequency?

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Neural Reflex

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Memorize

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Name the Afferent pathway of an Endocrine Reflex

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It doesn’t have an Afferent pathway

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Name the Efferent pathway of an Endocrine Reflex

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Hormone

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Name the Integrating center of Neural and Neuroendocrine Reflex

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Brain or

spinal cord

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Name the intergrating center of an Endocrine Reflex

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Endocrine Cell

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Name the Effector(s) of a Neural reflex

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Muscles &

glands, some adipose tissue

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Name the Effector(s) of a Neuroendocrine reflex

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Most cells of the body

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Name the Effector(s) of a Endocrine reflex

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Most cells of the body

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Which Reflex response includes contraction and secretion primarily?

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Neural Reflex

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Which Reflex sensor or receptor includes special and somatic sensory receptors?

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Neural Reflex&

Neuroendocrine Reflex

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Match the following:

*Food in stomach *Target Cell*Insulin *Stimulus*Spinal Cord & Brain *Classic

hormone*Adipose cell *integrating

center

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*Food in stomach = *Stimulus*Insulin = *Classic hormone*Spinal Cord & Brain = *Integrating center*Adipose cell = *Target Cell