Cystic Fibrosis Overview and Genetic Traits

Questions and Answers

What describes a Mendelian Trait?

Phenotype that depends on multiple loci

Example of cardiovascular disease

Phenotype that depends on one locus (correct)

Example of height

What is a Multifactorial Trait?

Trait depending on multiple genes (correct)

Trait depending on one gene

Example of Cystic Fibrosis

Example of Hemophilia

What is the function of mucus in the lungs?

To capture pathogens and dust

What is Mucociliary Transport?

Movement of mucus covering the respiratory epithelium by the beating of cilia Signup and view all the answers

What is responsible for the movement of mucus upwards towards the throat?

The beating of the cilia Signup and view all the answers

Which gene is mutated in Cystic Fibrosis?

CFTR gene Signup and view all the answers

What are mucins?

High molecular weight glycoproteins found in mucus Signup and view all the answers

What channels are normally found in healthy lung cells?

Two Cl- channels and one Na+ channel Signup and view all the answers

How does CF cause lung infections?

Mutations in CFTR lead to denser mucus that traps bacteria Signup and view all the answers

What symptoms of CF are observed in the gastrointestinal system?

Blocked pancreatic ducts resulting in decreased pancreatic enzymes Signup and view all the answers

What symptoms of CF are observed in the lungs?

Mucus-obstructed airways and bacterial infections Signup and view all the answers

What happens to the mucus and periciliary layers in Cystic Fibrosis?

Mucus layer is thick, periciliary layer is abnormally thin Signup and view all the answers

Study Notes

Cystic Fibrosis Overview

Cystic Fibrosis (CF) is caused by mutations in the CFTR gene, which codes for a chloride channel.
It is an autosomal recessive disorder characterized by fibrosis and cyst formation in the pancreas.
CFTR is expressed in the lungs, pancreas, sweat glands, and vas deferens.

Genetic Traits

Mendelian Trait: Depend on the genotype at one locus; examples include blood groups, eye color, and Cystic Fibrosis.
Multifactorial Trait: Depend on multiple loci; examples include height, IQ, and cardiovascular disease.

Lung Function and Mucus

Mucus captures pathogens and dust, playing a crucial role in respiratory health.
Mucociliary Transport: Movement of mucus by cilia in respiratory epithelium; involves rapid forward stroke and slow recovery stroke.
Cilia beating helps move mucus upwards towards the throat; facilitated by coughing or throat clearing.

CFTR Gene and Channels

CFTR gene is located on chromosome 7 and has over 1,500 identified mutations.
Normal lung cells have two chloride channels and one sodium channel, regulated by ATP and calcium ions.
The CFTR protein regulates chloride and sodium concentrations that affect mucus osmolarity.

Impact of CF on Mucus

In CF, mutated CFTR leads to decreased chloride secretion and increased sodium absorption.
This results in lower osmolarity in mucus, causing it to become denser and harder to clear.
The thickness and density of mucus lead to trapped bacteria and ineffective pathogen clearance.

Symptoms of Cystic Fibrosis

Lung Symptoms: Characterized by mucus-obstructed airways leading to chronic bacterial infections and decreased lung capacity.
Gastrointestinal Symptoms: Blocked pancreatic ducts cause decreased enzyme production, leading to digestive issues and intestinal blockage.

Mucus Composition

Mucus is comprised mainly of mucins, high molecular weight glycoproteins that trap pathogens and dust.
The periciliary fluid serves as a medium for cilia and is essential for effective mucociliary transport; CF causes it to be abnormally thin.

CF Progression

The compromised function of CFTR results in a cascade of cellular changes: less chloride is secreted, increased sodium influx, leading to dense mucus that traps bacteria and causes lung infections.

Description

This quiz covers essential aspects of Cystic Fibrosis, including its genetic basis, lung function, and the role of the CFTR gene. You'll explore how mutations can lead to this autosomal recessive disorder and the implications for respiratory health. Test your knowledge on Mendelian and multifactorial traits as they relate to Cystic Fibrosis.