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Flashcards in Channelopathies Deck (31)
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1

What is an iron channel?

Transmembrane proteins that create a gates, water filled pore to help establish and control membrane potential by modulating the flow of ions between the intracellular and extracelluar environments

2

What is the type of pump used in neuron action potential?

Na/K ATPase pump

3

What is pumped out of the cell in a neuronal action potential during repolarization?

Na

4

What occurs when there is a genetic type of channelopathy?

Loss of function: too little flux
Gain of function: too much flux

5

What occurs when there is an acquired type of channelopathy?

Acquired disorder, drugs or toxins

6

If there is a loss of function does that mean cell function is lost?

No

7

If there is a loss of function in Na/Ca channels what occurs?

Depressed excitability

8

If there is a loss of function in K channels what occurs?

Enhanced excitability

9

If there is abnormal depolarization of neuron cells what could happen?

Seizures and epilepsy

10

What are some gain of function mutations due to Na influx?

Primary erythromelalgia, paroxysmal extreme pain disorder

11

What is a loss of function mutation due to Na influx?

Channelopathy associated insensitivity to pain

12

What is the most prevalent genetic disorder in Caucasians?

Cystic fibrosis

13

What is the most severe symptoms of CF?

Chronic pulmonary infections
Irreversible airways damage

14

What causes CF?

Mutations in the CFTR (CF transmembrane conductance regulator)
Chloride channel of epithelial cells
Abnormal protein folding prevents normal Cl- influx

15

What is the pathophysiology behind CF?

Impaired movement of Cl and Na
Less extracell water
Thicker, dehydrated mucus at epithelial surfaces
Impaired ciliary function and airways bacterial clearance

16

What would a person from CF often suffer from?

Recurrent infections and inflammation

17

What are some complications of CF?

No absorption of NaCl, gall stones, enzyme retention, infertility (not sterile)
Salty skin, auto-digestion of the pancreas

18

What are some treatments for CF?

Chest percussion and inhaled hypertonic saline to clear pulmonary secretions
Antibiotics
Pancreatic enzyme development replacement
Nutrition
Lung transplant

19

What is the main issue with cardiac channelopathies?

Bad channels lead to bad rhythms
Can be lethal (sudden arrhythmic death cases, SIDS)

20

In a normal heartbeat, what causes excitation/contraction (depolarization)?

Na and Ca channels

21

In normal heartbeat, what causes relaxations (repolarization)?

K channels

22

What is Long QT syndrome?

Prolonged repolarization
Inefficient repolarization allows abnormal excitation

23

What is the most common cause of Long QT syndrome?

K channel loss of function
Maybe gain of function of Na or Ca channels

24

What drugs may cause long QT syndrome?

Antiarrhythmic drugs (K channel blockers)

25

What might trigger an arrhythmia?

Swimming, emotional stress, alarms, post-partum

26

What is the insulin/glycemic control regulated by?

K-ATP channel

27

What stimulates insulin secretion from pancreatic beta cells?

ATP and and sulphonylureas (SUR1)

28

How does the K cause insulin levels to decrease?

K channel activity repolarizes cells
Calcium channels close
Lower calcium depresses exocytosis/secretion

29

What is the mechanism of insulin secretagoges (SUL)?

Stimulate insulin secretion by interacting with the ATP sensitive K channels
Must have functional beta cells

30

What occurs in a loss of function K-ATP channelopathy?

Hyperinsulinemic hypoglycemia
Loss of function mutation of Kir6.2 or SUR1