Membranes Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Membranes and links to relevant pages within the course.
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| Which of the following immunoglobulin classes is chiefly responsible for the degranulation of mast cells and basophils: | View Page |
| Match the following terms with the statement that best describes each: | View Page |
| Proteins Involved in Adsorption The joining of the HIV and the host cell involves a spike on the HIV envelope and a CD4 molecule on the T-lymphocyte, macrophage, or brain cell.The molecule on the HIV spike is called glycoprotein 120 or gp120. The "120" refers to the molecular weight of the glycoprotein.While the CD4 site is important in viral binding, there is evidence that there are other molecules called co-receptors also involved.These molecules are embedded in the membranes of T-lymphocytes, macrophages, and brain cells. In the T-lymphocyte the abbreviated name of the protein molecule is CXCR4. | View Page |
| Overview Prevention of HIV exposure is the best line of defense to prevent occupational transmission of HIV as there is no vaccine available to develop specific immunity and the postexposure prophylaxis is toxic. Following appropriate workplace practices in the laboratory focus on preventing needlesticks or other sharps injuries and exposure of mucous membranes and abraded skin to HIV-infected blood or body fluids. | View Page |
| Face and Eye Protection Face shields, masks, and safety glasses protect your eyes and the mucous membranes of your nose and mouth.They must be worn whenever it is reasonably anticipated that splashing or spraying of blood or other contaminated materials may occur.Employees who wear prescription eyewear may be protected with a face shield, goggles, or with side shields attached to their glasses. | View Page |
| Gloves Gloves must be worn: when there is a reasonable chance of exposure to blood, other infectious body fluids, mucous membranes, or nonintact skin. during vascular access procedures, including phlebotomy. when handling contaminated items or surfaces.Wear only flat rings under gloves as large rings may tear gloves.Replace gloves: Between patient contacts If they are damaged or contaminated Before leaving the work area. Wash hands after removing gloves.Never wash disposable gloves. | View Page |
| The following workplace practices minimize risk of HIV exposure to mucous membranes or abraded skin: | View Page |
| Proteins Involved in Adsorption The joining of the HIV and the host cell involves a spike on the HIV envelope and a CD4 molecule on the T-lymphocyte, macrophage, or brain cell.The molecule on the HIV spike is called glycoprotein 120 or gp120. The "120" refers to the molecular weight of the glycoprotein.While the CD4 site is important in viral binding, there is evidence that there are other molecules called co-receptors also involved.These molecules are embedded in the membranes of T-lymphocytes, macrophages, and brain cells. In the T-lymphocyte the abbreviated name of the protein molecule is CXCR4. | View Page |
| The general signs and symptoms of smallpox include: | View Page |
| Agent: Pneumonic plague (Bacterium) Most likely means of dissemination: AerosolPrimary route of entry: InhalationGeneral signs and symptoms: High fever, chills, headache, coughing up of blood (hemoptysis), and toxemia, progressing rapidly to difficulty in breathing (dyspnea), and bluish discoloration of the skin and mucous membranes (cyanosis).There is another form of the disease called “bubonic plague”. While it is caused by the same organism, it is not transmissible through human contact. Pneumonic plague is transmissible through human contact. | View Page |
| O blood cell membranes contain which the following? | View Page |
| The growth of the yeast-like colonies shown in the upper image was obtained on blood agar from a skin culture only in the area overlaid by virgin olive oil. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The disease associated with this fungus is: | View Page |
| How is HBV Spread? Hepatitis B most often spreads when certain body fluids from an infected individual come in direct contact with another person.Contact may occur through:
a break or sore in the skin
a contaminated sharp
contact with mucous membranes that line the insides of the mouth, nose, eyes, and the genital organs.
HBV is not spread through casual contact, such as handshake, or through sweat. | View Page |
| Who is infected? Patients with Hepatitis B and other bloodborne infections can appear healthy, so you can't tell whose blood is infectious.So treat all:blood, body fluids, secretions (except sweat), excretions, non-intact skin, and mucous membranes as if they were infectious.That's what the term Standard Precautions means. | View Page |
| Standard Precautions! You cannot tell who is carrying a bloodborne pathogen. You must use Standard Precautions!This is required by the OSHA standard.Standard Precautions apply to all: BloodBody fluidsSecretions (except sweat)ExcretionsNon-intact skinMucous membranes | View Page |
| Gloves Must be Worn Gloves must be worn:
when there is a reasonable chance of exposure to blood, other infectious body fluids, mucous membranes, or nonintact skin,
during vascular access procedures, including phlebotomy,
or when handling contaminated items or surfaces.
| View Page |
| Face and Eye Protection The following protect your eyes and the mucous membranes of your nose and mouth: Face shields
Masks and safety glasses
They must be worn whenever it is reasonably anticipated that splashing or spraying of blood or other contaminated materials may occur.Employees who wear prescription eyewear may be protected with a face shield, goggles, or with side shields attached to their glasses. | View Page |
| Exposure Incident Even after taking all the proper precautions there is still a small chance of an exposure incident.Exposure incident:
Blood or another potentially infectious body fluid coming into direct contact with mucous membranes or nonintact skin.Parenteral exposure:
Needle stick or being cut by a contaminated sharp. | View Page |
| What are bloodborne pathogens? Bloodborne pathogens are infectious micro-organisms which live in the bloodstream.You can be exposed to bloodborne pathogens if you are injured with a contaminated needle.You can also be exposed if your mucous membranes, including eyes, mouth, or the inside of your nose come into contact with contaminated body fluids.
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| The cells marked by blue arrows in the photograph are associated with all of the following conditions except: | View Page |
| Hemoglobin H disease Hemoblobin H disease follows deletions of 3 of the 4 alpha globulin chains. Beta chains, unable to bind with insufficient numbers of alpha chains, form beta chain tetramers, or HbH.These beta chain tetramers appear as numerous dot size inclusions in erythrocyte cytoplasm, best seen in supravital brilliant cresyl blue stains (lower photograph).The most common molecular defect in alpha thalassemia is DELETION, not MUTATION; whereas, in beta thalassemia, the molecular defect is MUTATION.Leptocytes, as illustrated in the upper photograph,(lepto, derived from a Greek word meaning thin, fine, or slight), are characteristic of HbH disease. They have thinner cell membranes than the cells we recognize as target cells. They stain more lightly than normal erythrocytes and their centers are almost colorless.Subtle changes perhaps, but worth keeping in mind | View Page |
| A peripheral blood smear was submitted for review. The presence of sickle cells and target cells as shown is diagnostic of hemoglobin SC disease. | View Page |
| Ghost Cells Sometimes the red cells become so swollen that the cell membrane ruptures, causing the cell to lose hemoglobin. These empty membranes are known as "ghost" cells. | View Page |
| Familial disorders: summary Several additional familial and congenital disorders associated with atypical inclusions in WBCs are now recorded. These individual syndromes carry the following names: Fechtner, Alport, Epstein, Sebastian, and Paris-Trousseau.Fechtner syndrome( Peterson etal,Blood 65:397-406,1985)was described with 8 family members spanning 4 generations presenting with varying degrees of nephritis, deafness,and congenital cataracts. The syndrome is likely a variant of Alport syndrome with the addition of leukocyte inclusions and macrocytothemia. Several more cases involving other families have been reported. The inclusions resemble toxic Doehle bodies or those of the May-Hegglin anomaly by light microscopy, but are ultrastructurally unique.Alport syndrome in itself is autosomal dominant, X-linked , hereditary and characterized by sensorineural deafness and hereditary nephritis. It is believed to result from abnormal glycopeptide synthesis in renal basement membranes. Recurrent hematuria and slowly progressive renal insufficiency are clinical findings. Cataracts and platelet abnormalities may be added features.Epstein syndrome is essentially Alport syndrome with the addition of macrothrombocytopenia (Seri, et al. Hum Genet 110:182-186, 2002). Neutrophil inclusions are absent in this disorder; neutrophilic inclusions are considered part of the Fechtner syndrome. The Sebastian platelet syndrome is a variant of hereditary macrothrombocytopenia combined with neutrophil inclusions that differ from Doehle bodies, but are similar to those inclusions in Fechtner syndrome. (Greinacher, et al, Blut 61:282-288, 1990).Paris-Trousseau syndrome includes large platelets containing giant alpha granules identifiable in the peripheral blood.(Breton-Gorius, Blood 85:1805,1995) | View Page |
| More about lymphocytes, their impostors and varied faces In this photograph of blood cells from yet another submitted slide, we find cells resembling lymphoblasts with increased nuclear/cytoplasmic ratios and dense, finely meshed nuclear chromatin. In addition, note the extrusion of delicate strands of cytoplasm from the outer cell membranes (blue arrow). These are cells connoting hairy cell leukemia (HCL). Under scanning electron microscopy, the cytoplasmic extensions appear to be either slender microvilli or delicate pseudopods. The most helpful confirmatory finding is the detection of acid phosphatase isoenzymne 5 in the cytoplasm of suspected hairy cells by staining. The enzyme concentrates primarily in golgi bodies and in the nuclear membrane and its staining is not inhibited by the addition of tartrate. Stated in another way, hairy cells on the peripheral smears are detected by their staining positively for tartrate-resistant acid phosphatase. Be suspicious of HCL if marrow resists aspiration-a consequence of reticulin fibrosis of the marrow in HCL. | View Page |