Which of the following statements regarding transforming growth factor b (TGF-b) are true? a. TGF-b expression is autoregulated b. TGF-b enhances collagen synthesis c. TGF-b inhibits extracellular matrix production d. TGF-b may inhibit or promote cellular proliferation

Which of the following statements regarding transforming growth factor b (TGF-b) are true? a. TGF-b expression is autoregulated b. TGF-b enhances collagen synthesis c. TGF-b inhibits extracellular matrix production d. TGF-b may inhibit or promote cellular proliferation
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Answer: a, b, d  TGF-b appears to be one of the key cytokines in control of tissue repair. TGF-b is strongly chemotactic for neutrophils, T cells, monocytes, and fibroblasts. TGF-b activates inflammatory cells to elaborate fibroblast growth factor, TNFa, IL-1 and increase their synthesis of extracellular matrix proteins. TGF-b also induces both the infiltrating cells and resident cells to produce more TGF-b. This auto-induction amplifies its biological effects at the site of injury and may play an important role in the development of chronic fibrosis in a variety of pathologic states. TGF-b enhances collagen synthesis as well. Lastly, TGF-b may function as a mitogen or growth inhibitor for a wide variety of cell types, including selected cell types of mesenchymal origin. Whether TGF-b stimulates or inhibits proliferation depends on the presence of other growth factors, the concentration of TGF-b, and the cell density. Thus, at low doses, TGF-b stimulates the proliferation of densely plated human marrow fibroblasts, but is inhibitory at high concentrations
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Which of the following is/are true of the actions of transforming growth factor beta (TGF-b) during wound repair? A. Increased matrix and proteoglycan synthesis. B. Inhibition of proteases. C. Stimulation of plasminogen inhibitor. D. Chemotaxis for fibroblasts and macrophages. E. Autoinduction of TGF-b.

Description : Which of the following is/are true of the actions of transforming growth factor beta (TGF-b) during wound repair? A. Increased matrix and proteoglycan synthesis. B. Inhibition of proteases. ... of plasminogen inhibitor. D. Chemotaxis for fibroblasts and macrophages. E. Autoinduction of TGF-b.

Last Answer : Answer: ABDE DISCUSSION: Through autocrine and paracrine mechanisms TGF-b stimulates the deposition of collagen and other matrix components by fibroblasts, inhibits proteases, blocks plasminogen inhibitor, ... effects. The sustained production of TGF-b at the wound site leads to tissue fibrosis

Which of the following statements regarding IL-1 are correct? a. While IL-1 and TNFa share many biologic effects, IL-1 appears to be more potent b. IL-1 expression is in part autoregulated c. IL-1 inhibits prostaglandin production d. The ability of IL-1 to upregulate endothelial cell-neutrophil adhesion molecules is relatively limited

Description : Which of the following statements regarding IL-1 are correct? a. While IL-1 and TNFa share many biologic effects, IL-1 appears to be more potent b. IL-1 expression is in part ... production d. The ability of IL-1 to upregulate endothelial cell-neutrophil adhesion molecules is relatively limited

Last Answer : Answer: b IL-1 and TNFa share many biologic properties. In addition, each potentiates the effects of the other one when given concurrently. Overall, IL-1 alone probably has weaker effects than ... IL-1 provides a key step in the extravasation of leukocytes to sites of local inflammation and injury

Which of the following statement(s) is/are true concerning pharmacologic agents used to accelerate wound healing? a. A number of these agents are now currently approved for use in this country b. PDGF (platelet-derived growth factor) promotes fibroblast proliferation, chemotaxis, and collagenase synthesis c. PDGF has been demonstrated in a number of clinical trials to promote healing in chronic wounds d. Growth hormone functions by promoting fibroblast proliferation and collagen synthesis

Description : Which of the following statement(s) is/are true concerning pharmacologic agents used to accelerate wound healing? a. A number of these agents are now currently approved for use in ... healing in chronic wounds d. Growth hormone functions by promoting fibroblast proliferation and collagen synthesis

Last Answer : Answer: b, c Currently there are no approved clinical agents that accelerate normal healing. Although a number of clinical trials are in progress, no agents are currently ... hormone administration significantly accelerates donor site healing, presumably due to its effects in minimizing catabolism

In contrast to adult wound healing with scar formation, which of the following are characteristic of scarless fetal skin repair? A. Matrix rich in hyaluronic acid. B. Increased inflammatory response. C. Increased production of TGF-b. D. No collagen deposition. E. Minimal angiogenesis.

Description : In contrast to adult wound healing with scar formation, which of the following are characteristic of scarless fetal skin repair? A. Matrix rich in hyaluronic acid. B. Increased inflammatory response. C. Increased production of TGF-b. D. No collagen deposition. E. Minimal angiogenesis.

Last Answer : Answer: AE DISCUSSION: The ability of a fetus to heal without scar formation depends on its gestational age at the time of injury and the size of the wound defect. In ... repair has possible clinical applications in the modulation of adult fibrotic diseases and abnormal scar-forming conditions

Cytokines with clearly defined actions in acute inflammation and early tissue injury include which of the following? a. Cysteine-X-Cysteine (C-X-C) chemokines b. Tumor Necrosis Factor (TNFa) c. Transforming Growth Factor-b (TGF-b) d. Interleukin-6 (IL-6) e. Platelet Derived Growth Factor (PDGF)

Description : Cytokines with clearly defined actions in acute inflammation and early tissue injury include which of the following? a. Cysteine-X-Cysteine (C-X-C) chemokines b. Tumor Necrosis Factor (TNFa) c. Transforming Growth Factor-b (TGF-b) d. Interleukin-6 (IL-6) e. Platelet Derived Growth Factor (PDGF)

Last Answer : Answer: a, b, c, d, e Polypeptide mediators, such as TNFa and IL-1, are considered early response cytokines and are actively involved in the initiation of the ... of tissue repair. Thus, coagulation and platelet activation provide the initial foundation for subsequent cellular recruitment

Which of the following statements regarding fibroblasts and their function in wound healing are true? a. IL-1 has both inhibitory and promotional effects on fibroblast growth b. TNFa stimulates fibroblast collagen synthesis c. IL-1 and TNFa have opposite effects on the healing of bone d. In human clinical trials, EGF (epithelial growth factor) has been demonstrated to accelerate epidermal regeneration in cutaneous wounds

Description : Which of the following statements regarding fibroblasts and their function in wound healing are true? a. IL-1 has both inhibitory and promotional effects on fibroblast growth b. TNFa ... EGF (epithelial growth factor) has been demonstrated to accelerate epidermal regeneration in cutaneous wounds

Last Answer : Answer: a, d IL-1 appears to be important in the process of normal wound repair. IL-1 has been shown to stimulate skin fibroblast and keratinocyte growth, as well as ... that recombinant EGF enhances keratinocyte migration. EGF is also a potent chemoattractant for granulation tissue fibroblasts

Which of the following statement(s) is/are true concerning the proliferative phase of wound healing? a. The macrophage is the predominant cell type b. The pink or purple-red appearance of a wound is due to ingrowth and proliferation of endothelial cells c. Collagen, the dominant structural molecule of the wound matrix, contains two unique amino acids, hydroxyproline and hydroxylysine d. The predominant collagen type in a scar is type 3

Description : Which of the following statement(s) is/are true concerning the proliferative phase of wound healing? a. The macrophage is the predominant cell type b. The pink or purple-red appearance of a wound ... amino acids, hydroxyproline and hydroxylysine d. The predominant collagen type in a scar is type 3

Last Answer : Answer: b, c The proliferative phase of wound healing begins with the formation of a provisional matrix of fibrin and fibronectin as part of the initial clot formation. Initially, the provisional ... The principal collagen type scar is type 1, with lesser amounts of type 3 collagen also present

Which of the following statement(s) is/are true concerning the remodeling phase of wound healing? a. Total collagen content increases steadily through this phase b. The normal adult ratio of collagen is approximately 4:1 of type I to type III collagen. c. Eventually a scar will achieve the strength of unwounded skin d. The proteoglycans are responsible for the ground substance of the extracellular matrix

Description : Which of the following statement(s) is/are true concerning the remodeling phase of wound healing? a. Total collagen content increases steadily through this phase b. The normal adult ratio ... unwounded skin d. The proteoglycans are responsible for the ground substance of the extracellular matrix

Last Answer : Answer: b, d The transition from the proliferative phase to the remodeling phase of wound healing is defined by reaching collagen equilibrium. Collagen accumulation within the wound becomes maximal by ... in strength for six months or more, eventually reaching 70% of the strength of unwounded skin

Which of the following statements regarding hypercalcemia are true? A. The symptoms of hypercalcemia may mimic some symptoms of hyperglycemia. B. Metastatic breast cancer is an unusual cause of hypercalcemia. C. Calcitonin is a satisfactory long-term therapy for hypercalcemia. D. Severely hypercalcemic patients exhibit the signs of extracellular fluid volume deficit. E. Urinary calcium excretion may be increased by vigorous volume repletion.

Description : Which of the following statements regarding hypercalcemia are true? A. The symptoms of hypercalcemia may mimic some symptoms of hyperglycemia. B. Metastatic breast cancer is an unusual cause of ... fluid volume deficit. E. Urinary calcium excretion may be increased by vigorous volume repletion.

Last Answer : Answer: ADE DISCUSSION: Markedly elevated serum calcium levels produce polydipsia, polyuria, and thirst. Vigorous volume repletion and saline diuresis correct the extracellular fluid volume ... , from bony metastasis. The calcitonin effect on calcium is diminished with repeat administrations

Which of the following statement(s) is/are true concerning the microvascular and cellular response to shock? a. Osmodically induced mobilization of intracellular fluid is the initial response to restore intravascular volume b. With larger volume hemorrhagic shock deterioration of normal cellular transmembrane potential occurs resulting in an increase in extracellular sodium and water c. The accumulation of anaerobic metabolites override normal homeostatic vasomotor tone and contribute to the maladaptive vasodilatation d. Abnormal intracellular calcium homeostasis may contribute to the cellular dysfunction of shock

Description : Which of the following statement(s) is/are true concerning the microvascular and cellular response to shock? a. Osmodically induced mobilization of intracellular fluid is the initial ... d. Abnormal intracellular calcium homeostasis may contribute to the cellular dysfunction of shock

Last Answer : Answer: c, d Moderate hypovolemia results in a relatively rapid spontaneous restitution of intravascular volume through expansion of the plasma space. This plasma expansion by ... potassium pump. Cellular dysfunction also appears to be related to abnormal intracellular calcium homeostasis

Which of the following statements regarding TNFa are true? a. TNFa has a marked procoagulant effect b. Passive immunization of patients with neutralizing antibodies to TNFa improves survival from multi-organ system failure c. TNFa upregulates E-selectin expression d. The most potent known stimulus for TNFa production and release is IL-1

Description : Which of the following statements regarding TNFa are true? a. TNFa has a marked procoagulant effect b. Passive immunization of patients with neutralizing antibodies to TNFa improves survival from multi-organ ... expression d. The most potent known stimulus for TNFa production and release is IL-1

Last Answer : Answer: a, c TNFa has a marked procoagulant effect on endothelial cells, precipitating intravascular thrombosis. TNFa causes endothelial cells to release procoagulant activity (tissue factor), ... to produce TNFa, however the most potent stimulus for TNFa production and release is endotoxin

There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s) is/are true concerning energy converting transport? a. The site of energy conversion and transport in the plasma membrane involves the phospholipid component b. The Na+-K++-ATPase derives energy from hydrolysis of extracellular ATP c. In some systems, energy inherent in the transmembrane ion gradient can be used to drive transport of a second species d. Examples of species transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Description : There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s ... transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Last Answer : Answer: c, d The selectivity of the plasma membrane, although impressive, cannot account for the nonequilibrium composition of living cells. A cell can be maintained in a nonequilibrium state only by ... to drive the transport of a second species such as protons, calcium, amino acids, or glucose

Products of platelet degranulation include: a. Tumor necrosis factor b. Interleukin-1 c. Transforming growth factor b d. Platelet-derived growth factor

Description : Products of platelet degranulation include: a. Tumor necrosis factor b. Interleukin-1 c. Transforming growth factor b d. Platelet-derived growth factor

Last Answer : Answer: c, d The initial response to injury and disruption of a blood vessel is bleeding. The hemostatic response to this is clot formation to stop hemorrhage. Platelet plug ... . Tumor necrosis factor and interleukin-1 also stimulate fibroblast proliferation, however are produced by macrophages

Which of the following statements regarding endothelial cells in acute inflammation are true? a. Endothelial cells are characterized by phenotypic homogeneity b. Specific patterns of receptor expression regulate leukocyte adherence c. Endothelial cell nitric oxide generation regulates regional blood flow and leukocyte adhesion d. Endothelial cells may be capable of phagocytosis

Description : Which of the following statements regarding endothelial cells in acute inflammation are true? a. Endothelial cells are characterized by phenotypic homogeneity b. Specific patterns of receptor expression ... blood flow and leukocyte adhesion d. Endothelial cells may be capable of phagocytosis

Last Answer : Answer: b, c, d Endothelial cells are increasingly recognized to be phenotypically heterogeneous. Specific receptor molecules are expressed at various sites where they help to direct lymphocytes and ... rather, they possess the ability to direct and focus many aspects of an inflammatory event

Antibacterial agents can be classified with regard to their structure, mechanism of action, and activity pattern against various types of bacterial pathogens. Which of the following statement(s) is/are true concerning antimicrobial classes? a. Penicillins and cephalosporins share the compound structure of a b-lactam ring which binds to bacterial division plate proteins b. Tetracyclines and macrolides such as erythromycin inhibit bacterial ribosomal activity and therefore protein synthesis c. Aminoglycosides act in a similar fashion to tetracyclines and therefore are both bacteriostatic d. Sulfonamides and trimethoprim act synergistically to inhibit purine synthesis

Description : Antibacterial agents can be classified with regard to their structure, mechanism of action, and activity pattern against various types of bacterial pathogens. Which of the following ... are both bacteriostatic d. Sulfonamides and trimethoprim act synergistically to inhibit purine synthesis

Last Answer : Answer: a, b, d Penicillins, cephalosporins, and monobactams possess a b-lactam ring of some type and act to bind bacterial division plate proteins, thus inhibiting cell wall ... act in different mechanisms to inhibit protein synthesis, therefore two agents in combination act synergistically

Interleukin-6 is recognized as the cytokine primarily responsible for the alteration in hepatic protein synthesis recognized as the acute phase response. Which of the following statement(s) is/are true concerning acute phase protein response to surgical stress? a. Glucocorticoid hormones inhibit this response b. Proteins such as albumin and transferrin which serve in serum transport are generally increased in this response c. Examples of acute phase proteins include fibrinogen and C-reactive protein d. In general, the physiologic role of acute phase proteins are to reduce the systemic effects of tissue damage

Description : Interleukin-6 is recognized as the cytokine primarily responsible for the alteration in hepatic protein synthesis recognized as the acute phase response. Which of the following statement(s) is/are true ... physiologic role of acute phase proteins are to reduce the systemic effects of tissue damage

Last Answer : Answer: c, d IL-6 is now recognized at the cytokine primarily responsible for the alteration in hepatic synthesis recognized as the acute phase response. Glucocorticoid hormones augment ... that generally inhibit the tissue destruction that is associated with the local initiation of inflammation

Which of the following statements are true of oxidants? A. In addition to their pathophysiologic roles in inflammation, injury, and infection, oxidants also have physiologic roles. B. Oxidants may be generated from activated neutrophils and during reperfusion following a period of ischemia. C. The deleterious effects of oxidants include lipid peroxidation and cell membrane damage, oxidative damage to DNA, and inhibition of adenosine triphosphate (ATP) synthesis. D. The mechanism of ischemia-reperfusion injury involved the catalytic production of superoxide anion (O 2•) by the enzyme xanthine oxidase.

Description : Which of the following statements are true of oxidants? A. In addition to their pathophysiologic roles in inflammation, injury, and infection, oxidants also have physiologic roles. B. Oxidants may ... involved the catalytic production of superoxide anion (O 2 ) by the enzyme xanthine oxidase.

Last Answer : Answer: ABCD DISCUSSION: Oxidants are reactive oxygen metabolites that have both physiologic and pathophysiologic roles. As potent oxidizing agents, oxidants are involved in cytochrome P ... leukocyte infiltration and activation, causing further tissue damage by the release of cytotoxic proteases

Hemostasis and the cessation of bleeding require which of the following processes? A. Adherence of platelets to exposed subendothelial glycoproteins and collagen with subsequent aggregation of platelets and formation of a hemostatic plug. B. Interaction of tissue factor with factor VII circulating in the plasma. C. The production of thrombin via the coagulation cascade with conversion of fibrinogen to fibrin. D. Cross-linking of fibrin by factor XIII.

Description : Hemostasis and the cessation of bleeding require which of the following processes? A. Adherence of platelets to exposed subendothelial glycoproteins and collagen with subsequent aggregation of platelets and ... conversion of fibrinogen to fibrin. D. Cross-linking of fibrin by factor XIII.

Last Answer : Answer: ABCD DISCUSSION: Hemostasis requires the interaction of platelets with the exposed subendothelial structures at the site of injury followed by aggregation of more platelets in that area. ... form a stable clot that incorporates the platelet plug and fibrin thrombus into a stable clot

True statements regarding eicosanoids include which of the following? A. Prostaglandins and thromboxanes are synthesized via the cyclo-oxygenase pathway. B. The vasoconstricting, platelet-aggregating, and bronchoconstricting effects of thromboxane A 2 are balanced by the actions of prostacyclin, which produces the opposite effects. C. Leukotriene synthesis is inhibited by the action of nonsteroidal anti-inflammatory drugs (NSAIDs). D. The principal prostaglandins have a short circulation half-life and exert most of their effects locally.

Description : True statements regarding eicosanoids include which of the following? A. Prostaglandins and thromboxanes are synthesized via the cyclo-oxygenase pathway. B. The vasoconstricting, platelet-aggregating, ... prostaglandins have a short circulation half-life and exert most of their effects locally.

Last Answer : Answer: ABD DISCUSSION: The eicosanoids are a group of compounds arising from the metabolism of arachidonic acid. The prostaglandins and thromboxanes are synthesized via the cyclo-oxygenase ... effects and may be involved in the physiologic responses associated with anaphylactic and septic shock

Which of the following statements about extracellular fluid are true? A. The total extracellular fluid volume represents 40% of the body weight. B. The plasma volume constitutes one fourth of the total extracellular fluid volume. C. Potassium is the principal cation in extracellular fluid. D. The protein content of the plasma produces a lower concentration of cations than in the interstitial fluid. E. The interstitial fluid equilibrates slowly with the other body compartments.

Description : Which of the following statements about extracellular fluid are true? A. The total extracellular fluid volume represents 40% of the body weight. B. The plasma volume constitutes one fourth ... the interstitial fluid. E. The interstitial fluid equilibrates slowly with the other body compartments.

Last Answer : Answer: B DISCUSSION: The total extracellular fluid volume represents 20% of body weight. The plasma volume is approximately 5% of body weight. Sodium is the principal cation. The ... fluid and cerebrospinal fluid, the majority of the interstitial fluid exists as a rapidly equilibrating component

Factors that decrease collagen synthesis include all of the following except: A. Protein depletion. B. Infection. C. Anemia. D. Advanced age. E. Hypoxia.

Description : Factors that decrease collagen synthesis include all of the following except: A. Protein depletion. B. Infection. C. Anemia. D. Advanced age. E. Hypoxia.

Last Answer : Answer: C DISCUSSION: Collagen synthesis, an integral part of wound healing, is affected by many local and systemic factors. Protein depletion impairs fibroplasia. Hypoproteinemia leads to diminution of ... more than any other factor, wound infection is associated with the risk of wound failure

Cytokines are endogenous signals that stimulate: A. Local cell proliferation within the wound. B. The central nervous system to initiate fever. C. The production of “acute-phase proteins.” D. Hypoferremia. E. Septic shock.

Description : Cytokines are endogenous signals that stimulate: A. Local cell proliferation within the wound. B. The central nervous system to initiate fever. C. The production of “acute-phase proteins.” D. Hypoferremia. E. Septic shock.

Last Answer : Answer:ABCD DISCUSSION: Although cytokines exert primarily autocrine and paracrine effects, they may also cause systemic effects

Which of the following statements regarding cytokines is incorrect? A. Cytokines act directly on target cells and may potentiate the actions of one another. B. Interleukin 1 (IL-1) is a major proinflammatory mediator with multiple effects, including regulation of skeletal muscle proteolysis in patients with sepsis or significant injury. C. Platelet-activating factor (PAF) is a major cytokine that results in platelet aggregation, bronchoconstriction, and increased vascular permeability. D. Tumor necrosis factor alpha (TNF-a), despite its short plasma half-life, appears to be a principal mediator in the evolution of sepsis and the multiple organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates.

Description : Which of the following statements regarding cytokines is incorrect? A. Cytokines act directly on target cells and may potentiate the actions of one another. B. Interleukin 1 (IL-1) ... organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates.

Last Answer : Answer: C DISCUSSION: Cytokines are soluble peptide molecules that are synthesized and secreted by a number of cell types in response to injury, inflammation, and infection. Cytokines, which ... is thought to play a central role in the stress response, particularly in response to endotoxemia

Which of the following statements regarding angiogenesis are true? a. Angiogenesis is a seminal biologic event with clinical relevance limited to its effect upon tumor growth b. C-X-C chemokines regulate angiogenesis c. PF-4 has angiogenic properties d. Sites of atherosclerosis demonstrate chronic angiogenic activity

Description : Which of the following statements regarding angiogenesis are true? a. Angiogenesis is a seminal biologic event with clinical relevance limited to its effect upon tumor growth b. C-X-C ... c. PF-4 has angiogenic properties d. Sites of atherosclerosis demonstrate chronic angiogenic activity

Last Answer : Answer: b, d An important component of tissue repair and wound healing is the process of angiogenesis. This normal, physiologic process is a local, transient event which is ... between these factors may govern overall angiogenic potential in a variety of physiological and pathophysiological states

Thiamine is useful in: A. Collagen synthesis B. Clotting factor production C. Epithelial integrity D. Cellular energy production

Description : Thiamine is useful in: A. Collagen synthesis B. Clotting factor production C. Epithelial integrity D. Cellular energy production

Last Answer : D. Cellular energy production

Which of the following substances, not normally present in the circulation, trigger the initiating events in the hemostatic process? a. Thrombin b. Platelet factor 3 c. Tissue factor d. Collagen

Description : Which of the following substances, not normally present in the circulation, trigger the initiating events in the hemostatic process? a. Thrombin b. Platelet factor 3 c. Tissue factor d. Collagen

Last Answer : Answer: c, d The initiating agents for hemostasis involve two substances that are not normally present in the circulation-collagen and tissue factor. Tissue factor is released from ... phospholipid surface to form the so-called prothrombinase complex which catalyzes the formation of thrombin

Reconstitution of the epithelial barrier (epithelialization) begins within hours of the initial injury. Which of the following statement(s) is/are true concerning the process of epithelialization? a. Bacteria, protein exudate, and necrotic tissue all will compromise this process b. Epithelial cells exhibit contact proliferation c. Epithelialization occurs only from the margins of the wound d. Visible scarring can occur only when the injury extends deeper than the superficial dermis

Description : Reconstitution of the epithelial barrier (epithelialization) begins within hours of the initial injury. Which of the following statement(s) is/are true concerning the process of epithelialization? a. ... d. Visible scarring can occur only when the injury extends deeper than the superficial dermis

Last Answer : Answer: a, d The initial step of epithelialization involves epithelial cells from the basal layer of the wound edge flattening and migrating across the wound, completing wound coverage within 24- ... abrasions and burns may scar significantly. Whenever the dermis is incised, a scar will form

Cell regulation can be thought of as the effector side of cell communication. Most commonly cell regulation occurs by means of extracellular chemical messengers. Which of the following statement(s) is/are true concerning these messengers? a. Paracrine regulation involves a messenger which is produced and acts systemically b. The extracellular signal or stimulus is received by a receptor on or in the target cell c. Neurocrine regulation depends on a physical connection between the neuron and the target cell d. Most hormones, local mediators, and neurotransmitters readily cross the cell plasma membrane

Description : Cell regulation can be thought of as the effector side of cell communication. Most commonly cell regulation occurs by means of extracellular chemical messengers. Which of the following statement(s ... d. Most hormones, local mediators, and neurotransmitters readily cross the cell plasma membrane

Last Answer : Answer: b, c Depending on how the extracellular messenger arrives, cell regulation can be classified as paracrine, endocrine, or neurocrine. In paracrine regulation, a chemical messenger ... , local mediators, and neurotransmitters are water-soluble and cannot readily cross the plasma membrane

A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance of these differences is/are true? a. The cell membrane is able to maintain a 10,000 fold gradient between the extracellular concentration of ionized calcium and the intracellular concentration b. The key to these differences is the fact that the plasma membrane is normally impermeable to sodium, potassium and calcium c. The selectivity of biologic membranes is highly consistent and seldom changes d. The selectivity of cell membranes relates only to ions and not organic compounds

Description : A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance ... d. The selectivity of cell membranes relates only to ions and not organic compounds

Last Answer : Answer: a The survival of the cell requires that cytosolic composition be maintained within narrow limits, despite the constant influx of nutrients and the simultaneous outflow of waste. A ... be altered drastically as a result of regulatory or signaling processes that occur within the cell

Which of the following statement(s) is/are true concerning the cell plasma membrane? a. The plasma membrane is composed of amphipathic molecules b. The hydrophobic core of the lipid bilayer of the cell membrane contains specialized transport proteins which maintain the intracellular ionic milieu different from the extracellular fluid c. Plasma membrane proteins extend externally and bear phospholipid moieties which contribute to the cell coat d. The membrane proteins of nerve cells are highly voltage-dependent

Description : Which of the following statement(s) is/are true concerning the cell plasma membrane? a. The plasma membrane is composed of amphipathic molecules b. The hydrophobic core of the lipid bilayer of the ... contribute to the cell coat d. The membrane proteins of nerve cells are highly voltage-dependent

Last Answer : Answer: a, b, d The plasma membrane defines the boundary of the cell and serves to contain and concentrate enzymes and other macromolecule constituents. The plasma membrane is ... and bear carbohydrate moieties primarily as oligosaccharide chains that contribute to the cell coat or glycocalyx

Which of the following is/are true? A. Because of its thickness, the tensile strength of a healing wound on the eyelid is much less than one on the thick skin of the back. B. By 2 days, the experimental burst strength of skin is minimal since collagen has been formed in the wound but has not yet cross-linked. C. Wound strength reaches a plateau by 3 weeks. D. Wounds rarely, if ever, regain the strength of intact tissues.

Description : Which of the following is/are true? A. Because of its thickness, the tensile strength of a healing wound on the eyelid is much less than one on the thick skin of the back. B. By 2 days, ... strength reaches a plateau by 3 weeks. D. Wounds rarely, if ever, regain the strength of intact tissues.

Last Answer : Answer: BD DISCUSSION: Tensile strength measures load per cross-section area at rupture, whereas burst strength measures load required to break a wound, regardless of dimension. Therefore, skin wounds have ... a slower rate for more than a year. Wounds do not regain the strength of normal tissue

Which of the following is/are true concerning wound fibroblasts? A. Fibroblasts synthesize and secrete collagen molecules. B. Wound fibroblasts are derived from blood-borne precursor cells. C. Fibroblasts migrate to a wound along fibrin strands, which are used as a scaffold. D. Large amounts of fibrin or blood clot can act as a physical barrier to fibroblast penetration, which delays normal wound healing.

Description : Which of the following is/are true concerning wound fibroblasts? A. Fibroblasts synthesize and secrete collagen molecules. B. Wound fibroblasts are derived from blood-borne precursor cells. C. ... clot can act as a physical barrier to fibroblast penetration, which delays normal wound healing.

Last Answer : Answer: ACD DISCUSSION: Fibroblasts appear in the wound on about the third day of healing and begin to synthesize and secrete collagen molecules. Wound fibroblasts arrive from cells surrounding ... enzymes, and large amounts of fibrin and blood clot prevent fibroblasts from entering the wound

Which of the following statement(s) is/are true concerning the pulmonary response to shock? a. The acute pulmonary vascular response to shock differs markedly from that of systemic vasculature b. The pulmonary edema of ARDS occurs in the face of elevated left heart pressures c. The initial physiologic changes of ARDS involve the capillary endothelial cells and the type I pneumocyte d. Mechanisms proposed in the pathogenesis of ARDS include injury from mediators of inflammation elsewhere and from activated cellular elements e. A decrease in lung compliance may result from the loss of type I pneumocytes

Description : Which of the following statement(s) is/are true concerning the pulmonary response to shock? a. The acute pulmonary vascular response to shock differs markedly from that of systemic vasculature b. The ... elements e. A decrease in lung compliance may result from the loss of type I pneumocytes

Last Answer : Answer: c, d, e Contributing pathophysiologic processes to the pulmonary manifestations of shock include the pulmonary component of the cardiovascular response, disruption of the normal ... injury from mediators of inflammation elaborated elsewhere, and from activated cellular blood elements

The complement system consists of a series of serum proteins that exist in a quiescent or very low-level state of activation in the uninfected host. Which of the following statement(s) is/are true concerning complement activation? a. The alternate (properdin) pathway of complement activation can occur directly through contact with fungal or bacterial cell wall compounds b. Complement component fragments may serve to decrease vascular permeability c. Excessive complement activation can produce deleterious effects d. Fragments of certain complement components serve as chemoattractants to additional cellular components of the host defense mechanism

Description : The complement system consists of a series of serum proteins that exist in a quiescent or very low-level state of activation in the uninfected host. Which of the following ... certain complement components serve as chemoattractants to additional cellular components of the host defense mechanism

Last Answer : Answer: a, c, d Complement activation can occur through either classic or alternate (properdin) pathways, both of which eventuate in deposition of terminal complement pathway components on the ... and release of lysosomal enzymes that can directly damage certain target tissues, such as the lung

The following statement(s) is/are true concerning cellular defense mechanisms. a. Macrophages function solely as antigen processing cells in the initial reaction to exposure to an antigen b. Macrophages may become activated and secrete cytokines c. Macrophages serve as phagocytic cells in the tissues but not within the bloodstream d. Polymorphonucleocytes (PMNS) are normally present in only small numbers within the tissue and enter an area of infection through diapedesis

Description : The following statement(s) is/are true concerning cellular defense mechanisms. a. Macrophages function solely as antigen processing cells in the initial reaction to exposure to an antigen b. Macrophages ... in only small numbers within the tissue and enter an area of infection through diapedesis

Last Answer : Answer: b, d A wide variety of cell types serve to provide host defense at several levels. Macrophages act as the initial antigen processing cell that serves to ... through diapedesis after chemotactic stimuli are excluded by macrophages, bacterial breakdown products, and complement activation

Which of the following statement(s) is/are true concerning wound contraction? a. Wound contraction accounts for similar rates of reduction of wound size regardless of their location b. The fibroblast, at the cellular level, is the primary force driving wound contraction c. Excessive wound contraction, when occurring over a joint, may lead to disability d. Actin microfillaments are found in fibroblasts and may play a role in wound contracture

Description : Which of the following statement(s) is/are true concerning wound contraction? a. Wound contraction accounts for similar rates of reduction of wound size regardless of their location b. The fibroblast ... d. Actin microfillaments are found in fibroblasts and may play a role in wound contracture

Last Answer : Answer: b, c, d Wound contraction is an important event which contrasts healing open wounds and closed incisions. When open wounds contract, the surrounding skin is pulled over the open wound ... number in contracting wounds and are felt to play an active role in the process of wound contraction

Which of the following statements are true? 1. Cytokinins promote stomatal opening 2. Sprays of indole -3 acetic acid can inhibit premature fruit fall 3. The growth movements caused by a unilateral stimulus are known as nastic movements 4. The seeds of desert plants will not germinate unless they have been subjected to a high temperature for some time Questions Select the correct answer from the following: (a) 1, 2, and 4 (b) 2 and 4 (c) 1, 2, and 4 (d) 1, 2, 3, and 4

Description : Which of the following statements are true? 1. Cytokinins promote stomatal opening 2. Sprays of indole -3 acetic acid can inhibit premature fruit fall 3. The growth movements caused by a unilateral stimulus are known as nastic movements 4. The ... 4 (b) 2 and 4 (c) 1, 2, and 4 (d) 1, 2, 3, and 4

Last Answer : Ans:(a)

Which of the following statements about septic shock are true? A. A circulating myocardial depressant factor may account for the cardiac dysfunction sometimes seen with shock due to sepsis or SIRS. B. A cardiac index (CI) of 6 liters per minute per square meter of body surface, a pulmonary capillary wedge pressure of 15 mm. Hg, and a systemic vascular resistance index (SVRI) of 800 dynes-sec/(cm 5-m 2) is a hemodynamic profile consistent with septic shock. C. An increase in SvO 2 in septic patients may be explained by the finding of anatomic arteriovenous shunts. D. Results of human trials employing antimediator therapy, such as antiendotoxin antibodies, IL-1 receptor antagonist, and tumor necrosis factor (TNF) antibodies, have confirmed animal studies that demonstrate a significant im

Description : Which of the following statements about septic shock are true? A. A circulating myocardial depressant factor may account for the cardiac dysfunction sometimes seen with shock due to sepsis or ... animal studies that demonstrate a significant improvement in survival with the use of such agents.

Last Answer : Answer: AB DISCUSSION: Shock due to sepsis or SIRS frequently manifests as a hyperdynamic cardiovascular response, consisting of an elevated CI and a decreased SVR or SVRI. Occasionally, ... been encouraging thus far in human clinical trials, despite the promising results from many animal studies

Which of the following statements are true of the multiple organ dysfunction syndrome (MODS)? A. The “two-hit” model proposes that secondary MODS may be produced when even a relatively minor second insult reactivates, in a more amplified form, the systemic inflammatory response that was primed by an initial insult to the host. B. The systemic inflammatory response syndrome (SIRS), shock due to sepsis or SIRS, and MODS may be regarded as a continuum of illness severity. C. Prolonged stimulation or activation of Kupffer cells in the liver is thought to be a critical factor in the sustained, uncontrolled release of inflammatory mediators. D. The incidence of MODS in intensive care units has decreased owing to increased awareness, prevention, and treatment of the syndrome.

Description : Which of the following statements are true of the multiple organ dysfunction syndrome (MODS)? A. The two-hit model proposes that secondary MODS may be produced when even a relatively ... intensive care units has decreased owing to increased awareness, prevention, and treatment of the syndrome.

Last Answer : Answer: ABC DISCUSSION: MODS is part of a clinical continuum that begins with the systemic inflammatory response syndrome, which is the host's stress response to any major insult such ... pathogenesis of MODS, the incidence of MODS continues to increase without a significant improvement in outcome

Total body mass is composed of an aqueous component and a nonaqueous component. The nonaqueous component is made up of which of the following? a. Liver b. Tendons c. Skeletal muscle d. Extracellular fluid e. Adipose tissue

Description : Total body mass is composed of an aqueous component and a nonaqueous component. The nonaqueous component is made up of which of the following? a. Liver b. Tendons c. Skeletal muscle d. Extracellular fluid e. Adipose tissue

Last Answer : Answer: b, e The nonaqueous portion of total body mass is made up of bones, tendons, and mineral mass as well as adipose tissue. The aqueous component contains the body cell ... and circulating blood cells. Also contributing to the aqueous portion is the interstitial fluid and intravascular volume

Which of the following statements regarding the alternative complement pathway are true? a. C1, C4 and C2 are involved b. NH3 apparently activates complement via this pathway c. Factors B and D are involved d. Endotoxin activates complement via the alternative pathway

Description : Which of the following statements regarding the alternative complement pathway are true? a. C1, C4 and C2 are involved b. NH3 apparently activates complement via this pathway c. Factors B and D are involved d. Endotoxin activates complement via the alternative pathway

Last Answer : Answer: b, c, d The alternative pathway differs from the classic pathway in that the first steps involving C1, C4 and C2 are bypassed. (See Figure 6-3 previously reproduced.) ... been correlated with impaired renal function and the presence of complement components at the sites of renal injury

Which of the following statements regarding neutrophils are true? a. The neutrophil undergoes final maturation after release into the circulation b. Patients with chronic granulomatous disease have a defective neutrophil H-oxidase system c. Neutrophil killing of bacteria is achieved by oxidants, proteinases and cationic proteins d. The normal human neutrophil circulates in the blood for 7–10 days

Description : Which of the following statements regarding neutrophils are true? a. The neutrophil undergoes final maturation after release into the circulation b. Patients with chronic granulomatous disease have a defective ... proteins d. The normal human neutrophil circulates in the blood for 7-10 days

Last Answer : Answer: b, c The neutrophil is a migratory phagocytic cell that defends the host against bacteria and eliminates necrotic tissue. The neutrophil matures in the bone marrow and is ... phagocytose bacteria, they are unable to kill the intracellular microbes and chronic, unresolved infections result

Which of the following statements regarding the complement system are true? a. Complement activation yields products which are directly cytotoxic as well as products which act indirectly via activated leukocytes b. Complement products referred to as anaphylatoxins include C1, C3a, C4a, and C5a c. The principal role of C5a is in bacterial opsonization d. The alternative and classical pathways converge proximal to generating the membrane attack complex (C5b-9)

Description : Which of the following statements regarding the complement system are true? a. Complement activation yields products which are directly cytotoxic as well as products which act indirectly via activated ... and classical pathways converge proximal to generating the membrane attack complex (C5b-9)

Last Answer : Answer: a, d The complement system is composed of two different but linked sequences, the classic and alternative pathways. The pathways involve serum proteins that act to amplify the inflammatory-immune ... the C5 level proximal to generating the membrane attack complex (C5b-9) (Figure 6-3)

Which of the following statements regarding the transmission of infectious agents through blood transfusions is/are true? A. The transmission rates for human immunodeficiency virus (HIV) have been decreasing progressively since the early 1980s. B. The transmission rates of hepatitis have been decreasing steadily since the 1980s. C. Cytomegalovirus (CMV) is the infectious agent most commonly transmitted in blood. D. Severely immunocompromised patients (such as patients undergoing transplantation) should receive specially screened blood products.

Description : Which of the following statements regarding the transmission of infectious agents through blood transfusions is/are true? A. The transmission rates for human immunodeficiency virus (HIV) ... patients (such as patients undergoing transplantation) should receive specially screened blood products.

Last Answer : Answer: ABCD DISCUSSION: The incidence of both HIV and hepatitis transmitted via blood transfusions has been steadily decreasing since the 1980s. This is related to improved ... , severely compromised patients such as those undergoing transplantation should receive CMV-negative blood products

Under certain circumstances, the gut may become a source of sepsis and serve as the motor of systemic inflammatory response syndrome. Microbial translocation is the process by which microorganisms migrate across the mucosal barrier to invade the host. Which of the following mechanisms can promote bacterial translocation? a. An increased number of gut bacteria b. Altered intestinal mucosal permeability c. Decreased host defense mechanisms d. Lack of enteral feeding

Description : Under certain circumstances, the gut may become a source of sepsis and serve as the motor of systemic inflammatory response syndrome. Microbial translocation is the process by which microorganisms ... intestinal mucosal permeability c. Decreased host defense mechanisms d. Lack of enteral feeding

Last Answer : Answer: a, b, c, d 99 Translocation is promoted in three general ways: 1) altered permeability of the intestinal mucosa as caused by shock, sepsis, distant injury, or cell toxins; 2) ... trauma patient d. Fifty percent of non-nitrogen caloric requirements should be provided in the form of fat

Which of the following tissues contain significant collagen useful for placing sutures to allow the prolonged tension necessary to maintain tissue approximation? a. Dermis b. Intestinal submucosa c. Muscular fascia d. Blood vessel wall

Description : Which of the following tissues contain significant collagen useful for placing sutures to allow the prolonged tension necessary to maintain tissue approximation? a. Dermis b. Intestinal submucosa c. Muscular fascia d. Blood vessel wall

Last Answer : Answer: a, b, c, d It takes at least three weeks for collagen to undergo sufficient remodeling and cross linking to attain moderate strength. Since most skin sutures are removed at one to ... , Scarpa's fascia, and blood vessel wall represent a partial list of tissues with high collagen content

Which of the following interfere with normal collagen formation or cross-linking? A. Beta-aminopropionitrile. B. Iron chelators. C. Vitamin C depletion. D. Proline analogs (e.g., cis-hydroxyproline). E. D-Penicillamine.

Description : Which of the following interfere with normal collagen formation or cross-linking? A. Beta-aminopropionitrile. B. Iron chelators. C. Vitamin C depletion. D. Proline analogs (e.g., cis-hydroxyproline). E. D-Penicillamine.

Last Answer : Answer: ABCDE DISCUSSION: Intramolecular and intermolecular cross-links are crucial for collagen structural stability. Formation of cross-links can be inhibited by two ... concentration, proline analogs prevent collagen formation with minimal effects on noncollagenase protein synthesis

Which of the following is an adhesion glycoprotein? A. Fibronectin. B. Tenascin. C. Laminin. D. Hyaluronic acid. E. Collagen type IV.

Description : Which of the following is an adhesion glycoprotein? A. Fibronectin. B. Tenascin. C. Laminin. D. Hyaluronic acid. E. Collagen type IV.

Last Answer : Answer: ABC DISCUSSION: Cell adhesion glycoproteins such as fibronectin, vitronectin, laminin, and tenascin provide a railroad track to facilitate epithelial and mesenchymal cell migration over the wound ... , and collagen type IV is a protein that is a crucial component of basement membrane

Local anesthetics: A. Inhibit transmission of nerve impulses by increasing sodium membrane permeability and the displacement of ionized calcium. B. Are classified as amides or esters. C. Produce peripheral vasodilation. D. Are weak acids.

Description : Local anesthetics: A. Inhibit transmission of nerve impulses by increasing sodium membrane permeability and the displacement of ionized calcium. B. Are classified as amides or esters. C. Produce peripheral vasodilation. D. Are weak acids.

Last Answer : Answer: BC DISCUSSION: Local anesthetics act within the nerve membrane, where they inhibit transmission of nerve impulses by reducing sodium membrane permeability and the displacement of ionized ... based on this bond. All local anesthetics except cocaine produce vasodilatation and are weak bases

In the nutritional support of patients with cancer, which of the following statements is/are true? A. Nutritional support benefits the patient's lean body mass but does not enable the tumor to grow. B. In experimental animals, the growth of implanted tumors is directly proportional to the amount of calories and protein supplied. C. Prospective randomized trials of nutritional support utilizing chemotherapy and radiation therapy have revealed benefits to patients receiving total parenteral nutrition. D. Studies of nutritional support for patients with cancer about to undergo surgery revealed decreased morbidity and mortality, especially morbidity from sepsis.

Description : In the nutritional support of patients with cancer, which of the following statements is/are true? A. Nutritional support benefits the patient's lean body mass but does not enable ... with cancer about to undergo surgery revealed decreased morbidity and mortality, especially morbidity from sepsis.

Last Answer : Answer: B DISCUSSION: The problem with the patient with cancer is a very vexing one. Clearly, one of the metabolic effects of cancer, cachexia, affects patients in the last quartile ... undoubtedly reveal that there are certain nutrients that tumors require, which probably should be best avoided