Deck 3: Extracellular Matrix

Question 1

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, highly stretchable skin, and kyphoscoliosis (hump back). The physician should suspect

A) scurvy
B) Ehler-Danlos syndrome
C) Marfan syndrome
D) cutis laxa
E) mucopolysaccharidosis

Answer 1

B

Question 2

A patient who is suffering from 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

Answer 2

D

Question 3

In Fig. Basallamina3, the clear area indicated by the tip of the arrow is rich in

A) hyaluronic acid
B) fibronectin
C) laminin
D) perlacans
E) cadherins

Answer 3

C

Question 4

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

Question 5

In Fig. Img_017, the predominant connective tissue element shown in this photomicrograph is a type of collagen fiber. Which type of collagen fiber is it?

A) type I
B) type II
C) type III
D) type IV
E) type VII

Question 6

An African-American patient had surgery, and a very thick, elevated growth has formed 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

Question 7

An elderly patient is seen by his dermatologist because he developed itching and blisters on his skin. If the blistering involves the region indicated by the arrows in this electron micrograph (Basallamina4), 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

Question 8

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. This component is

A) hyaluronic acid
B) keratan sulfate
C) dermatan sulfate
D) heparan sulfate
E) chondroitin-4-sulfate

Question 9

In Fig. Img_015b, which of the following familial disorders is due to abnormal development of the tissue shown in the accompanying photomicrograph?

A) Marfan syndrome
B) Beal's syndrome
C) Ehler-Danlos syndrome
D) cutis laxa
E) Supraclavicular aortic stenosis syndrome

Question 10

A 9-month-old infant is seen by her pediatrician, who notices a lack of weight gain as well as thin, knobby joints. The parents tell the physician that they are making their own baby food and that their daughter 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 also 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

Question 11

In Fig. Img_016, which of the following familial disorders is due to abnormal development of the tissue represented in the accompanying photomicrograph?

A) Ehler-Danlos syndrome
B) Marfan syndrome
C) osteogenesis imperfecta
D) Stickler's syndrome
E) benign hypermobility syndrome

Question 12

In Fig. Basallamina2, the arrow points to 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

Question 13

A male patient is seen for the first time by a 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

Question 14

A patient with Alport's syndrome is usually a male who presents with poor kidney function and blood in the urine. The mutation causing this syndrome involves the gene for the $\alpha$ -3 chain of type IV collagen. The reason why the patient is usually a male is that

A) males tend to get more urinary tract infections than females
B) the gene for $\alpha$ -3 chain of collagen is located on the Y chromosome
C) the gene for $\alpha$ -3 chain of collagen is located on the X chromosome
D) the gene for $\alpha$ -3 chain of collagen is located on chromosome 21 of males
E) hypertrophy of the prostate in elderly males exacerbates the incidence of kidney infections