Apical Specializatoin

Question 1

What are 2 Types of Peripheral Microtubules?

Answer 1

1. “A” Microtubule

• 13 Tubulin protofilaments
• Side-by-side

2. “B” Microtubule

• 10 Tubulin protofilaments
• Does not form Complete Circle
• Shares a portion of its wall with “A” microtubule

*“Pair of Arms”

• Contain: DYNEIN
  
  • Microtubule protein
  • Produce Movement

Question 2

What is NEXIN?

Answer 2

1. Protein that links “A” microtubule with “B” microtubule of adjacent doublet
2. Restricts Sliding Movement

Question 3

What are Axonemes?

Answer 3

1. Form inner core of Cilia and Flagella
2. Continuous with Basal Bodies
   * Centrioles with triplets of (9) microtubules and Tubulin protofilaments (Anchor)

Question 4

What is Primary Ciliary Dyskinesia?

Answer 4

1. Mutation in gene coding for Ciliary Proteins
2. Inherited
3. Ultrastructural defects affecting DYNEIM ARMS (results in movement problems)
4. Conditions

• Sinusitis
• Chronic Respiratory Tract Infection
• Ear Infection
• Infertility- In males
• Situs Inversus Totalis (50% of people with PCD)

Question 5

What is Kartagener Syndrome?

Answer 5

1. Condition

• Situs Inversus
• Chronic Sinusitis
• Bronchietasis

Question 6

What are characteristics of Microvilli?

Answer 6

1. 20 to 30 Actin filaments cross-linked by FIMBRIN AND FASCIN
   * Bound by Myosin I
2. Stabalizes Spectrin
   * Anchors terminal web to Apical Cell Membrane
3. Undergo Myosin based movement
4. Surface coated with GLYCOCALYX

• Used for Cell recognition
• Contain proteins for digestion of Macromolecules
  
  • Pancreatic
  • Lipase
  • Trypsin
  • Chymotrypsin

*Gluten Enteropathy (Celiac Sprue)

• Wheat protein allergy
• Immune-mediated Inflammation

Question 7

What are Sterocilia?

Answer 7

1. Immotile Microvilli
2. Resemble Microvilli
   * Extremely Long
3. Actin filaments anchor to plasma membrane by ERZIN (actin protein)
4. Location

• Epidiymis
• Ductus Deferens (for absorption)
• Sensory cells of inner ear