Basic Medical Histology (GMS6630) Unit 1 - Multiple Choice Questions

1. Which of the following techniques is most commonly used to locate glyscogen in cells?

Methylene blue staining

Feulgen's reaction

Periodic acid-Schiff (PAS) reaction

Enzyme histochemistry

Immunohistochemistry

Periodic acid-Schiff (PAS) reaction

Which of the following is the most characteristic type of intermediate filament protein found in epithelial cells?

Actin

Cytokeratin

Desmin

Glial fibrillary acidic protein

Integrin

Cytokeratin

Which of the following is the location of the electron-transport system?

Cristae

Inner mitochondrial membrane

Intracristal space

Matrix granules

Outer mitochondrial membrane

Inner mitochondrial membrane

Which of the following substances characteristically increases in abundance with increasing age in terminally differentiated cells such as neurons and muscle?

Cyclin

Desmin

Lipofuscin

Osmium

Phalloidin

Lipofuscin

How many somatic chromosomes are in a normal human karyotype?

22

23

24

44

46

44

A patient with cancer possesses cells that are undergoing mitosis at a very rapid rate. The contractile rings that are formed during cytokinesis are composed of

thin filaments

intermediate filaments

thick filaments

microtubules

neurofilaments

The answer is thin filaments. Contractile rings, composed of thin (actin) filaments form around the site where the cleavage furrow forms during telophase. Just prior to complete separation of the two daughter cells, the midbody forms, which is then incorporated into one of the two cells. Intermediate filaments, thick filaments, and neurofilaments (intermediate filaments of neurons) do not participate in the formation of contractile rings. The midbody is composed of polar microtubules and a bridge of cytoplasm.

Radioautography is the method of choice for revealing which of the following in a tissue section?

Sites of synthesis of various molecules

Molecular weights of products of cell synthesis

Diameter of a secretory cell

Number of copies of a particular species of mRNA

Cell structure in unstained tissue sections

Sites of synthesis of various molecules

Which of the following structures are organelles formed by the fusion of primary lysosomes and phagosomes and also sites of active digestion of phagocytosed materials?

Autophagosomes

Heterophagosomes

Secondary lysosomes

Polysomes

Residual bodies

Secondary lysosomes

Which of the following are composed primarily of actin or actin-like proteins?

Basal bodies

Cilia

Cytochalasins

Intermediate filaments

Microfilaments

Microfilaments

Ribosomes are not found in mature red blood cells. From this fact and from knowledge of ribosome function and distribution which of the following can be deducted?

Mature red blood cells are incapable of protein synthesis

Red blood cells lack nucleoli throughout their life cycle

Mature red blood cells lack cytoplasmic enzymes

Mature red blood cells contain inactive RER

Mature red blood cells contain smooth ER

Mature red blood cells are incapable of protein synthesis

The agents in which of the following procedures are intended to stabilize tissue structure by coagulating proteins and promoting cross-linking?

Clearing

Dehydration

Embedding

Fixation

Mounting

Fixation

A malignant cell of mesenchymal origin contains cytoplastic filaments composed of vimentin. Which of the following indicates the average diameter of these filaments?

5-7 nm

10-12 nm

24 nm

50-70 nm

100-120 nm

10-12 nm

Which of the following is the location of Krebs cycle enzymes and mitochondrial DNA?

Cristae

Inner mitochondrial membrane

Intracristal space

Matrix granules

Mitochondrial matrix

Mitochondrial matrix

Which of the following terms is applied to the smallest chromatin subunit in eukaryotic cells?

Chromosome

Euchromatin

Genes

Heterochromatin

Nucleosome

Nucleosome

Which of the following procedures entails impregnating a specimen with a solvent of the embedding medium?

Clearing

Dehydration

Fixation

Mounting

Rehydration

Clearing

Which of the following best described the appearance of a unit membrane under a transmission electron microscope?

Junctional complex

Lipid bilayer

Pentalaminar structure

Porous structure

Trilaminar structure

Trilaminar structure

Which of the following form the purse-string constriction around the equator of mitotic cells?

Centrioles

Intermediate filaments

Microfilaments

Microtubules

Protofilaments

Microfilaments

Which of the following is true of the Barr body?

Attaches to the inner surface of the plasma membrane during interphase

Is composed of euchromatin during the mitotic phase of the cell cycle

Its DNA replicated during every other cell cycle in normal males

In normal females, it is a member of a homologous chromosome pair

Occurs when homologous chromosomes fail to separate during anaphase

In normal females, it is a member of a homologous chromosome pair

Which of the following is the site of steroid hormone synthesis?

Golgi complex

Free polyribosomes

Mitochondria

RER

SER

SER

Which of the following methods involves immersing fixed tissue in increasing concentrations of ethanol in water?

Clearing

Dehydration

Embedding

Mounting

Rehydration

Dehydration

Which of the following is the site of actin and tubulin synthesis?

Centrioles

Free polyribosomes

Mitochondria

RER

SER

Free polyribosomes

Which of the following pairs of cellular structures regulate the distribution of membranous vesicles and organelles through their influence on microtubule polymerization?

Centrioles and satellite bodies

Chromosomes and mitotic spindles

Cilia and flagella

Golgi apparatus and endosomes

Laminal and intermediate filaments

Centrioles and satellite bodies

Because of the frequent presence of ribosomes on its outer surface, the nuclear envelope may be considered a specialized portion of which organelle?

Golgi complex

Nucleolus

Plasma membrane

RER

SER

RER

Ribosomal RNA (rRNA) is synthesized by which of the following?

Free polyribosomes

Nuclear envelope

Nucleolus

RER

SER

Nucleolus

The fluidity of the plasmalemma has well-established clinical significance. Which of the following molecules decreases the cell membrane fluidity?

a. glycerol

b. phosphate group

c. cholesterol

d. integral proteins

e. peripheral proteins

Cholesterol decreases membrane fluidity. The polar heads of phospholipids molecules are composed of glycerol, to which a positively charged nitrogenous group is attached by a negatively charged phosphate group. Unsaturated fatty acyl molecules increase membrane fluidity. Integral and peripheral proteins do not have an effect on membrane fluidity.

2. A patient with asthma has difficulty breathing and is treated with albuterol, a drug that relaxes bronchiolar smooth muscles. Albuterol acts as a(n)

a. cholinergic receptor antagonist

b. cholinergic receptor agonist

c. adrenergic receptor antagonist

d. adrenergic receptor agonist

e. inhibitor of kinase phosphorylases

Adrenergic Receptor Agonist. Albuterol is an agonist that acts on beta2-adrenergic receptors, which are located mainly on the cell membranes of bronchial tissues and, therefore, do not have many side effects. If it were an antagonist, then it would cause smooth muscle constriction

A patient who had surgery for ovarian cancer is placed on a combination of cisplatin and taxol therapy. Taxol is an antimitotic agent that

a. affects microfilaments

b. affects intermediate filaments

c. has defective dynein

d. prevents the polymerization of microtubules

e. stabilizes microtubules

Stablizes microtubules. Unlike most antimitotic agents that interfere with polymerization or depolymerization of microtubules, taxol stabilizes microtubules so that they cannot shorten or lengthen. In this fashion, the mitotic spindle apparatus cannot change its length, thus preventing the movement of the chromosomes during the mitotic event. Dynein, microfilaments, and intermediate filaments are unaffected by taxol.

A 9-month-old female Jewish baby, whose parents were born in Poland, is seen by her pediatrician because of neurological problems, including generalized paralysis and blindness. The pediatrician should suspect that the child has

a. spina bifida

b. cranial nerve X (vagus nerve) disorder

c. Tay-Sachs disease

d. Fabry disease

e. Refsum disease

Tay-Sachs disease.

Tay-Sachs disease affects mostly children of Eastern European Jewish ancestry as well as in certain families in Louisiana of Cajun ancestry. Children with this lysosomal storage disease cannot catabolize GM2 gangliosides that accumulate in their lysosomes, and the enlarged lysosomes interfere with cell function. The interference is most problematic in the neurons of the central nervous system and causes death by the third year of life. Neither spina bifida nor vagus nerve disorders would cause generalized paralysis or blindness. Fabry disease, although a lysosomal-storage, is due to an X chromosomal defect and affects males only. Refsum disease is due to the accumulation of phytanic acid, a by-product of chlorophyll metabolism and affects older children who already eat fresh fruits and vegetables.

Acid hydrolases are synthesized on the rough endoplasmic reticulum and are delivered to the Golgi complex to be packaged and distributed to their final destination. Patients whose protooncogenes have mutated to form ras protein related products known as ADP-ribosylation factor (ARF) may interfere with

a. coatomer II (COP II) synthesis

b. coatomer II (COP II) assembly

c. coatomer II (COP II) dissociation from vesicles

d. clathrin synthesis

e. clathrin assembly

Coatomer II (COP II) assembly.

Delivery of proteins manufactured on the rough endoplasmic reticulum to the Golgi complex is accomplished in COP II-coated vesicles. ARF catalyzes the assembly of COP II molecules to form coatomer on the cytoplasmic aspect of these transfer vesicles. Synthesis of COP II proteins as well as the disassembly of the coatomer is not influenced by ARF. Clathrin coats mediate the endocytotic pathway as well as the pathway that leads away from the trans-Golgi network.

Patients with sickle cell anemia possess hemoglobin S, a mutated form of hemoglobin. Hemoglobin S is

a. synthesized on free ribosomes

b. synthesized on the rough endoplasmic reticulum

c. modified in the Golgi apparatus

d. packaged in the trans-Golgi network

e. stored in condensing vesicles

Synthesized on free ribosomes.

Hemoglobin, whether normal or mutated, is present freely in the cytosol; therefore, it is synthesized on free ribosomes. Only proteins that are to be packaged are synthesized on the rough endoplasmic reticulum. Because hemoglobin is not packaged, it does not enter the Golgi apparatus.

A neonatal baby boy is observed to have malformed hands, feet, and skull. Additional examination displays jaundice, hepatomegaly, and hypotonic muscles with psychomotor retardation. The pediatrician diagnoses the baby with cerebrohepatorenal syndrome (Zellweger syndrome). This condition is due to problems with which of the following organelles?

a. mitochondria

b. lysosomes

c. early endosomes

d. late endosomes

e. peroxisomes

Peroxisomes.

Children with cerebrohepatorenal syndrome die at an early age due to mutations in their peroxin genes that code for defective receptors that are unable to transfer enzymes destined for peroxisomes into these organelles. Mitochondria, lysosomes, and endosomes are not affected by this mutation.

A 20-year-old man presenting with deteriorating vision in both eyes, especially his central vision, seeks help from his ophthalmologist. The patient also evidences cardiac dysrhythmia and an apparent demyelination of the optic nerve. The ophthalmologist suspects Leber hereditary optic neuropathy, a condition caused by a point mutation that is not X-linked but is transmitted only by females. This condition is due to problems with which of the following?

a. lysosomes

b. early endosomes

c. late endosomes

d. mitochondria

e. peroxisomes

Mitochondria.

Leber hereditary optic neuropathy is due to a point mutation on the mitochondrial DNA. Because the spermatozoon does not contribute mitochondria to the zygote, only the female can transmit this condition to her offspring. Lysosomes, peroxisomes, early and late endosomes do not possess DNA.

Which description refers to cadherins?

a. They are peripheral proteins.

b. They are associated with cell-cell adhesion.

c. They are associated with adherence to the basal lamina.

d. They have binding sites for heparin sulfate.

e. They are associated with hemidesmosomes.

They are associated with cell-cell adhesion.

Cadherins are integral proteins that are designed to assist cells to maintain contact with one another. Hemidesmosomes, heparin sulfate, and basal lamina are all associated with cell to extracellular matrix contact

Dynein arms are always attached to one of the following. Which one is that structure?

a. central sheet

b. singlets

c. subunit A

d. subunit B

e. radial spoke

Subunit A

Dynein arms are microtubule-associated proteins that function in the achievement bending the cilium. These molecular motors are attached to the subunit A of the axoneme. The central sheet and the radial spokes are both composed of an elastic protein that become stretched during the "cocking" of the axoneme and, as they return to their normal length, they effect ciliary motion.

A 2-month-old baby is brought to be examined, and the physician notices that he has flaccid muscles, a smaller head than usual, a large tongue, a short nose, and a broad face. The parents say that the baby is very quiet and hardly ever cries. The pediatrician suspects aneuploidy. The child probably has which of the following chromosomal configurations?

a. Monosomy

b. Trisomy

c. Normal diploid complement

d. Haploid complement

e. Tetraploid complement

Trisomy.

The baby most probably has trisomy 21, Down syndrome, in which chromosome 21 is present instead of two chromosomes, one from the mother and the other from the father. During meiosis, nondisjunction occurs, so that one cell has the extra chromosome 21 and the other cell is monosomic; that is, it is missing chromosome 21

A patient with a chromosomal complement of XXY has

a. trisomy of the autosomes

b. Turner syndrome

c. monosomy of the sex chromosomes

d. Klinefelter syndrome

e. a female phenotype

Klinefelter syndrome. The patient has Klinefelter syndrome and exhibits a male phenotype. Because there are three sex chromosomes, this is not a monosomy or a trisomy of the autosomes. Turner syndrome is exhibited by females who lack the second X chromosome.

A patient with a chromosomal complement of XO has

a. trisomy of the sex chromosomes

b. Turner syndrome

c. monosomy of the autosomes

d. Klinefelter syndrome

e. a male phenotype

Turner syndrome.

Patients with Turner syndrome are females who lack the second X chromosomes; therefore, they are monosomal for the sex chromosomes not for the autosomes. Turner syndrome is a male phenotype with an extra X chromosome.

A patient with a chromosomal complement of XXX has

a. male phenotype

b. female phenotype

c. a very short life span

d. a higher IQ than his/her siblings

e. trisomy of autosomes

Female phenotype.

The patient is a female who has the triple X syndrome, thus she has an extra sex chromosome rather than trisomy of the autosomes. These patients usually have a lower IQ than their siblings but have a normal life span and can even give birth to children with a normal chromosomal complement.

Which RNA synthesis is catalyzed by RNA polymerase II?

a. tRNA

b. rRNA that codes for the large ribosomal subunit

c. rRNA that codes for the small ribosomal subunit

d. mRNA

e. tRNA that carries the start codon

mRNA.

RNA polymerase II catalyzes the synthesis of messenger RNA (mRNA). The synthesis of all tRNA is catalyzed by RNA polymerase III, whereas all rRNA synthesis is catalyzed by RNA polymerase I.

During a routine examination of a 3-year-old child, the pediatrician notes that the color of the pupil is white and that the child is cross-eyed. She asks the father if there are any cases of retinoblastoma in the family, and, because the answer is in the affirmative, she calls in a pediatric ophthalmologist. The ophthalmologist knows that retinoblastoma is due to the mutation of the Rb gene (retinoblastoma gene) and that it is a recessive trait.

Retinoblastoma can metastasize to the brain via the

a. optic nerve

b. superior division of the oculomotor nerve

c. trochlear nerve

d. abducent nerve

e. inferior division of the oculomotor nerve

Optic Nerve.

The retina is attached to the brain via the optic nerve; therefore, malignant cells can use the optic nerve as a passageway to the brain. The superior and inferior divisions of the oculomotor nerve, the trochlear nerve, and the abducent nerve all innervate the external muscles of the eye and do not contact the retina.

During a routine examination of a 3-year-old child, the pediatrician notes that the color of the pupil is white and that the child is cross-eyed. She asks the father if there are any cases of retinoblastoma in the family, and, because the answer is in the affirmative, she calls in a pediatric ophthalmologist. The ophthalmologist knows that retinoblastoma is due to the mutation of the Rb gene (retinoblastoma gene) and that it is a recessive trait.

Not all cases of retinoblastoma have a familial component. There is the sporadic form of retinoblastoma in which the child's normal genetic complement does not predispose the child to have retinoblastoma. If this child had the sporadic form of retinoblastoma, then

a. one copy of the Rb genes mutated

b. both copies of the Rb genes mutated

c. the patient's future children will most probably have one mutated Rb gene

d. the patient's future children will most probably have two mutated Rb genes

e. the mutated Rb gene is known as a proto-oncogene

both copies of the Rb genes mutated.

Because retinoblastoma is a recessive trait, both copies of the Rb gene would have to have mutated. The normal gene, which codes for the Rb protein is known as a proto-oncogene, whereas its mutated form is known as an oncogene. Because the mutations did not occur in the gametes, the patient's future children will not have any mutated Rb genes.

Chiasmata formation

a. occurs during metaphase II

b. results in the exchange of genetic material between non-homologous chromosomes

c. occurs during the pachytene phase

d. results in nondisjunction

e. results in the formation of the synaptonemal complex

occurs during the pachytene phase.

Chiasmata formation occurs during the pachytene phase of prophase I of the first meiotic event. Homologous pairs of chromosomes line up during the zygotene phase of prophase I, forming the synaptonemal complex, thus permitting crossing over to occur during the pachytene phase so that there could be a random exchange of genetic material that contributes to a more diverse gene pool. Nondisjunction occurs when the homologous pairs of chromosomes separate during anaphase I.

During meiosis, some chromosomes do not separate from each other. This is called

a. diplotene

b. nondisjunction

c. diakinesis

d. zygotene

e. leptotene

Nondisjunction.

During the anaphase I of meiosis, the homologous chromosomes may remain attached to each other, and the two newly formed cells will have unequal chromosomal numbers. This process is known as nondisjunction. Diplotene, zygotene, diakinesis, and leptotene are phases of prophase I of the first meiotic division.

The binding of cyclin B to CDK1 (cyclin-dependent kinase 1) permits the cell to progress from

a. S phase into G2 phase

b. G2 phase into M phase

c. G1 phase into G2 phase

d. G1 phase into S phase

e. prometaphase into metaphase

G2 phase into M phase.

The formation of the cyclin B-CDK1 complex allows the cell to enter the mitotic cycle, that is, progress from G2 phase into the M phase. The cell cycle cannot go from G1 to G2 directly; it has to first go through the S phase. Cyclins D and E are required to enter S from G1. Cyclins A and B are both required for the entry from S phase into G2 phase.

A patient whose symptoms include discolored, violet-colored skin with large blisters, fever, malaise, rapid heart rate, and a great deal of pain is diagnosed with necrotizing fasciitis. The rapid spread of Staphylococus aureus and group A streptococci that ravage the connective tissue of this patient is due to the ability of these organisms to destroy one of the components of the extracellular matrix of the skin. Which is this component?

a. hyaluronic acid

b. keratan sulfate

c. dermatan sulfate

d. heparan sulfate

e. chondroitin-4-sulfate

hyaluronic acid.

Hyaluronic acid is a very large glycosaminoglycan that is not sulfated and is not bound to a protein core. It is able to bind a very large number of proteoglycans, thus forming a very large molecule with an enormous domain. This very large macromolecule complex is responsible for the "gel state" of the extracellular matrix. Staphylococus aureus and group A streptococci possess hyaluronidase that cleaves hyaluronic acid and converts the gel to a "sol (soluble) state," making it much easier for the microorganisms to spread very rapidly through the connective tissue element, destroying the tissues in its path. Some call these microorganisms, flesh-eating bacteria. The other four glycosaminoglycans are much smaller and, by binding to a protein core, form proteoglycans. They are not large enough by themselves to form a gel.

An African-American patient had surgery and forms a very thick, elevated growth at the site of the skin incision. This elevated growth is known as a keloid and is due to the excessive accumulation of

a. hyaluronic acid

b. proteoglycans

c. type I collagen

d. elastic fibers

e. oxytalan fibers

Type 1 collagen.

African Americans are especially predisposed to the excessive accumulation of type I collagen at the site of wound healing.

The tensile strength of the healing wound about a week after the cut surfaces of the skin are sutured to each other is about 10% of the normal tensile strength of skin. The initial weakness of the dermis during wound healing is due to the material elaborated by fibroblasts to close the wound in a very rapid fashion. This material is

a. type I collagen

b. type II collagen

c. type III collagen

d. type V collagen

e. type VII collagen

Type III collagen.

The first collagen to be formed by fibroblasts to effect initial closure of a wound is type III collagen (reticular fibers). This slender collagen type has a very weak tensile strength and is replaced by type I collagen within 4 weeks of the injury and, at that point, the tensile strength of the healed tissue is about 80% of the tensile strength of intact skin.

A male patient is seen for the first time by his physician; the patient has very thin, slender legs and unusually long, slender fingers. The patient's history indicates that he has been diagnosed with a connective tissue disorder, known as Marfan syndrome. The mutation that causes this syndrome affects

a. tropomyosin

b. troponin

c. microfibrils

d. elastin

e. fibrillin

Fibrillin.

Marfan syndrome is due to a mutation that involves the gene that codes for the component of elastic fibers known as fibrillin. Individuals with this condition frequently have cardiovascular problems, including aortic aneurysm, high blood pressure, dislocation of the lens of the orb. Their collagen fibers, muscle fibers, and actin filaments are normal.

A patient with leukocyte adhesion deficiency will have a/an

a. autosomal dominant disorder

b. sex-linked chromosomal disorder

c. dysfunctional adhesins

d. dysfunctional integrins

e. dysfunctional cadherins

Dysfunctional integrins.

Leukocyte adhesion deficiency is an autosomal recessive disorder that results in the inability of white blood cells to synthesize the beta chains of their integrin molecules. Therefore, the leukocytes are incapable of adhering to the endothelial cells and are unable to migrate to the site of inflammation. Patients with this disease have difficulties resisting bacterial infections. Adhesins are surface antigens of many microorganisms that permit them to adhere to mammalian cell surfaces, whereas cadherins are responsible for cell-cell adhesions.

A 9-month-old baby is seen by her pediatrician, who notices a lack of weight gain in the infant as well as thin, knobby joints. The parents tell the physician that they are making their own baby food and that the child has been very irritable and cries a lot when she is crawling on the floor. The baby's gums appear to be overly red. The pediatrician suspects lack of vitamin C in the baby's diet and recommends that the parents switch to commercially prepared baby foods and urges them to offer the child citrus fruits. Additionally, the child is to receive high doses of vitamin C for 7 days and a lower dose for an additional 30 days. Vitamin C is necessary for the synthesis of normal

a. elastin

b. fibrillin

c. tropocollagen

d. troponin

e. hyaluronic acid

Tropocollagen.

Vitamin C is necessary for the hydroxylation of proline residues. Hydroxyproline is required to hold the alpha chains of tropocollagen molecules to each other. The synthesis of elastin, fibrillin, and hyaluronic acid are not affected by vitamin C. Troponin is a protein present in skeletal and cardiac muscle and is not affected by the lack of vitamin C.

A 12-year-old child complains to his physician that he frequently dislocates his joints. Upon examination, the physician notes that the patient has hyperextensive joints, has highly stretchable skin, and has kyphoscoliosis (hump back). The doctor should suspect

a. scurvy

b. Ehlers-Danlos syndrome

c. Marfan syndrome

d. cutis laxa

e. mucopolysaccharidosis

Ehlers-Danlos syndrome.

The doctor should suspect Ehlers-Danlos syndrome because individuals with this genetic disorder have very flexible joints, occasional kyphoscoliosis, and skin that can be stretched a couple of inches, and upon release, the skin returns to its previous position. A patient with scurvy would be recognized by bleeding gums and possible disfiguration of the long bones of the leg. Patients wtih Marfan syndrome are usually tall and thin and possess especially long fingers. Cutis laxa is characterized by stretchy skin that hangs loosely in folds. Patients with mucopolysaccharidosis die at a very young age.

The lamina densa of the basil lamina is an area that is rich in

a. type I collagen

b. type II collagen

c. type III collagen

d. type IV collagen

e. type VII collagen

Type IV collagen.

The lamina densa of the basal lamina is formed mostly of a network of type IV collagen. Type I collagen is the most common collagen present in the body, and it forms thick bundles of collagen fibers. Type II collagen is present in the matrix of cartilage, and type III collagen is also known as reticular fibers, a thin fibrous collagen with many sugar groups that allow it to bind silver stain. Type VII collagen is located in the lamina reticularis of the basement membrane.

The clear area indicated represents the basil lucida and is rich in

a. hyaluronic acid

b. fibronectin

c. laminin

d. perlecan

e. cadherins

Laminin.

The clear area indicated by the tip of the arrow in this electron micrograph represents the lamina lucida component of the basal lamina. It is rich in laminin, a glycoprotein that facilitates adhesion between the basal lamina and epithelial cells. Fibronectin is located on the connective tissue side of basal lamina. Cadherins are transmembrane proteins that permit cells to contact and adhere to one another. Neither hyaluronic acid nor perlecans is located in this region.

An elderly patient is seen by his dermatologist because he developed itching and blisters of his skin. If the blistering involves the region indicated by the arrow in this electron micrograph and if the patient is shown to have IgG along the same area indicated by the arrows, the patient is probably suffering from

a. dermatitis herpetiformis

b. atopic dermatitis

c. pemphigus vulgaris

d. pemphigus foliaceus

e. bullous pemphigoid

Bullous pemphigoid.

Bullous pemphigoid is a relatively rare autoimmune condition occurring in elderly patients in which the patient produces IgG against his or her hemidesmosomes and separation of the epidermis from the dermis by the formation of blisters. Dermatitis herpetiformis is similar to bullous pemphigoid in that the vesicles form at the interface of the epidermis and dermis and is accompanied by itching. However, the condition begins at the highest points of the dermal ridges, and it is only later that the entire epidermal-dermal interface becomes involved. The main difference is that IgA rather than IgG is the antibody involved. Pemphigus vulgaris and pemphigus foliaceus are both blistering conditions; however, the blister is intraepidermal and involved autoantibodies against desmosomes. Atopic dermatitis is more prevalent in children than in adults and is usually located at the joints where flexion occurs. It is accompanied by edema, a thicker than normal epidermis, and excessive development of the rete apparatus.