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Madisen Bender – Physiology
12/10/2016
Final Writing Assignment
Cystic Fibrosis
Cystic fibrosis is an autosomal recessive disease in which the exocrine glands produce
thick secretions of mucus which can cause problems in the lungs, pancreas, liver, digestive
system, sinuses, and reproductive organs. Although this genetic disorder occurs in all racial and
ethical groups, it is most common among those with Northern European Ancestry and ranks as
one of the most common life threatening genetic disease of Caucasians in the United States. This
disease is most often detected in infancy or childhood; one in every 2,500 births results in cystic
fibrosis. There is a one in four chance of forming this disease if both parents carry the
appropriate gene. Effects of cystic fibrosis (CF) begin before birth, extend into early childhood,
and become increasingly more serious as the individual ages. The average life span for those
with this disease in 1950 was five years. Advancements in the science and medical community
have increased this number currently to a life expectancy of 40 years. Cystic Fibrosis is a very
serious and common life threatening disease.
This disease is known to be caused by the mutated gene cystic fibrosis transmembrane
conductance regulator (CFTR) which codes for a CFTR protein. Each person carries a CFTR
gene in their DNA, but cystic fibrosis occurs when both the mother and the father carry an
abnormal CFTR gene and the baby inherits both of them. This glycoprotein is formed in the
Endoplasmic Reticulum, that forms Cl- channels in the apical membrane of epithelial cells. This
protein does not move through the Golgi Apparatus to be processed which is responsible for
modifying, sorting, and packaging proteins for secretion. In result, CFTR does not get correctly
inserted in to vesicles that would guide it into the plasma membrane. Therefore, salt (NaCl) and
water (H20) movement across epithelial membranes of pancreatic ductules, sweat glands, and
respiratory airways is abnormal. This insufficient movement of particles produces salty sweat,
blocks several important internal ducts, decreases production of sodium bicarbonate, and
produces thick mucus in the pancreas and lungs which promotes pulmonary disorders. Exocrine
glands normally produce thin, slippery secretions such as mucus, sweat, tears and digestive
juices. With cystic fibrosis, the mucus is thick and sticky. This unusually thick mucus interferes
with the normal functioning of certain body systems. People with CF also lose excessive
amounts of salt when they sweat causing the homeostasis of salt in the body to be off balance,
which may cause abnormal heart rhythms.
One of the major organs cystic fibrosis influences is the lungs and respiratory system.
CF causes the mucus that coats the breathing tubes to become incredibly thick and sticky
