1
Q
What symptoms are present in cystic fibrosis (CF)?
A
- Chronic cough
- Diarrhea
- Wheezing, respiratory issues
- Runny nose
- Salty skin
2
Q
What is CF characterized by?
A
Defective epithelial ion transport
3
Q
What are the secretory consequences of having CF?
A
- Thick, viscous secretions in the lungs, pancreas, liver, intestine and reproductive tract
- Increased salt content in sweat gland secretions
4
Q
Where is the faulty CF gene located?
A
- Chromosome 7
- Autosomal recessive
5
Q
What chance is there that an offspring of carriers of CF develops CF?
A
25%
6
Q
What chance is there that an offspring of carriers of CF does not develop CF?
A
75%
7
Q
What does the CF gene code for?
A
CF transmembrane conductance regulator (CFTR)
8
Q
What is the consequence of defective CFTR?
A
- Defective cAMP-activated chloride and sodium channel that is present on the surface of many epithelial cells
- NaCl becomes trapped in the cell, which pulls water in and dehydrates mucus
9
Q
What is the mutation in the CF gene?
A
- The amino acid phenylalanine in position 508 is missing (delta F508)
- Three letter codon is missing
10
Q
What are the underlying molecular mechanisms of CF?
A
- Mutated CFTR gene (gene is transcribed in the nucleus)
- Abnormal mRNA sequence (mRNA exits the nucleus) and binds to ribosome on RER (translation)
- Protein goes to the Golgi where it is processed or targeted for destruction
- Either no channel or faulty channel that does not allow NaCl out of the cell
11
Q
70-80% of patients with CF lack what?
A
The receptor
12
Q
What homeostasis is altered in CF?
A
Na+ and Cl- intracellular concentrations increase drastically
13
Q
What causes salty skin in CF?
A
- When CF is missing, chloride ions are not reabsorbed
- As sweat rises in the cell in the CFTR duct, cells do not reclaim the NaCl
14
Q
What are the accepted treatments for children and adults with CF?
A
- Airway clearance therapy
- Antibiotics
- Bronchial dilators
- Vitamin supplements
- Enzymes to aid digestion
15
Q
What is happening in cancer cells that explains the large size of their nucleus and the relatively small amount of cytoplasm?
A
Actively dividing cells (such as cancer cells) are duplicating the amount of DNA within their nucleus, which explains why it is larger (as it takes more room)
16
Q
What are symptoms of Tay-Sachs disease?
A
- Slow loss of muscle control and brain function
- Accumulation of gangliosides (loss of hexoaminidase A enzyme)
- Vision problems or blindness
17
Q
Why might the genetic test for mutations in the Tay-Sachs gene be more accurate than the test that detects decreased amounts of hexosaminidase A?
A
- Hexosaminidase A detection is an INDIRECT measurement
- The genetic test is a DIRECT measurement
18
Q
Is CFTR a chemically-gated, a voltage-gated, or a mechanically-gated channel protein?
A
Chemically-gated since it binds to ATP, allowing the channel to open and transport Cl- out of epithelial cells and into the lumen
19
Q
Why would failure to transport NaCl into the airways cause the secreted mucous to be thick?
A
- If NaCl is secreted into the lumen of the airways, water moves into the lumen as well, which thins the mucous
- If NaCl cannot be secreted into the lumen, there will be no fluid movement to thin the mucous
20
Q
Is CFTR protein on the apical or basolateral surface of the sweat gland epithelium?
A
The epithelial surface that faces the lumen of the sweat gland is the APICAL membrane
21
Q
Why would an individual with cystic fibrosis require pancreatic enzymes to be taken whenever they eat?
A
Because the thick mucus in the pancreatic ducts block the secretion of digestive enzymes into the intestine
22
Q
In which type of diabetes is the signal pathway for insulin more likely to be defective?
A
Type 2 diabetes
23
Q
In which form of diabetes are the insulin receptors more likely to be up-regulated?
A
- In type 1 diabetes, insulin is not secreted by the pancreas
- Type 1 is therefore more likely to cause up-regulation of the insulin receptors
24
Q
In the insulin reflex pathway, name the stimulus, sensor, integrating center, output signal, target, and response.
A
- Stimulus: increase glucose concentration in the blood
- Sensor: beta cells of the pancreas
- Integrating center: beta cells
- Output signal: insulin
- Target: any tissues of the body that responds to insulin
- Response: decrease in blood glucose
25
Why can't glucose simply leak into cells when the blood glucose concentration is higher than the intracellular glucose concentration?
Because glucose is lipophobic; must enter through facilitated diffusion
26
What happens to the rate of insulin secretion when blood glucose levels fall? What kind of feedback loop is operating?
- A decrease in blood glucose decreases insulin release
| - Negative feedback loop
27
To which of the three classes of hormones do the thyroid hormones belong?
Amino-acid derivatives (tyrosine + iodine)
28
If a person's diet is low in iodine, predict what happens to thyroxine production.
A person is unable to make thyroid hormones
29
In a normal person, when thyroid hormone levels in the blood increase, will negative feedback increase or decrease the secretion of TSH?
Decrease the secretion of TSH
30
In a person with a hyperactive gland that is producing too much thyroid hormone, would you expect the level of TSH to be higher or lower than in a normal person?
Lower (strong negative feedback)
31
Why is radioactive iodine (rather than some other radioactive element, such as cobalt) used to destroy thyroid tissue?
- Radioactive iodine is concentrated in the thyroid gland, and therefore selectively destroy the tissue
- Other radioactive elements distribute more widely throughout the body and may harm normal tissues
32
If levels of TSH are low and thyroxine levels are high, is Grave's disease a primary disorder or a secondary disorder (one that arises as a result of a problem with the anterior pituitary)? Explain your answer.
- In secondary hypersecretion disorders, you would expect the levels of the trophic hormones to be ELEVATED (which is not the case)
- The oversecretion of thyroid hormones is NOT the result of elevated TSH
- Grave's disease is a primary disorder that is caused by a problem in the thyroid gland itself
33
Antibodies are proteins that bind to the TSH receptor. From that information, what can you conclude about the cellular location of the TSH receptor?
The TSH receptor is a membrane receptor, as antibodies (proteins) cannot cross the cell membrane
34
In Graves' disease, why doesn't negative feedback shut off thyroid hormone production before it becomes excessive?
- Negative feedback is capable of shutting off endogenous TSH production
- But, it fails to respond to the thyroid gland's production of hormones as a result of the binding of antibody to the TSH receptor
35
What is Guillain-Barré syndrome? When does it appear?
- Relatively rare paralytic condition
- Strikes after a viral infection or an immunization
- Lost sensation returns slowly as the body repairs itself
36
What division(s) of the nervous system may be involved in Guillain-Barré syndrome?
- Problems with both afferent and efferent motor neurons
| - Or, problems with the CNS integrating center
37
In GBS, what would you expect the results of a nerve conduction test to be?
- In GBS, myelin around neurons is destroyed
| - Decreased conduction speed or blocked conduction
38
What is AMAN? What might it be triggered by?
- Acute motor axonal polyneuropathy (AMAN)
| - Triggered by a bacterial infection
39
How is AMAN initiated?
Damage of axons at neuromuscular junctions, the synapses between somatic motor neurons and skeletal muscles
40
Name diseases involving altered synaptic transmission.
- Parkinson's disease
- Depression
- Schizophrenia
41
What is the periodic paralysis disorder caused by?
Na+ or Ca2+ ion channel mutations in the membranes of the skeletal muscle fibers
42
What effect would continued movement of Na+ have on the membrane potential of muscle fibers?
The influx of positive charge depolarizes the muscle, and it remains depolarized
43
What is hypokalemic periodic paralysis characterized by?
Decreased blood levels of K+ during paralytic episodes
44
What is hyperkalemic periodic paralysis (hyperKPP) characterized by?
Either normal or increased blood levels of K+ during episodes
45
What ion is responsible for the repolarization phase of the muscle action potential, and in which direction does this ion move across the muscle fiber membrane? How might this be linked to hyperKPP?
- K+ leaves the cell during repolarization
| - The movement of K+ from the muscle fiber could contribute to elevated extracellular K+
46
In people with hyperKPP, when do attacks occur?
After a period of exercise (i.e., after a period of repeated muscle contractions
47
What are the characteristics of hyperkalemic periodic paralyses?
- Only last a few minutes to a few hours
- Generally involve only the muscles of the extremities
- Muscles become weak and unable to contract (flaccid paralysis)
48
What drugs may prevent hyperkalemic flaccid paralyses?
Diuretics, which increase the rate at which the body excretes water and ions (including Na+ and K+)
49
Why does an Na+ channel that does not inactive result in a muscle that cannot contract (flaccid paralysis)?
If the muscle fiber is unable to repolarize, it cannot fire additional action potentials
50
Why does oral glucose help individuals with hyperkalemic flaccid paralysis?
- Glucose stimulates insulin release, and insulin increases Na+-K+-ATPase activity
- Removes Na+ from the cells and helps them repolarize
51
What is a heart attack?
Area of the heart that is dying because of a lack of blood supply (myocardial infarction)
52
Why would oxygen and nitroglycerin help during a myocardial infarction?
- Administration of oxygen increases O2 that reaches the heart and the brain
- Nitroglycerin is metabolized to nitric oxide, which dilates blood vessels and improves blood flow
53
What effect would the injection of isotonic saline have on an individual undergoing a heart attack? On their intracellular fluid volume? On their total body osmolarity?
- The extracellular volume increases
| - The intracellular volume and total body osmolarity does not change
54
What are the effects of tissue plasminogen activator (t-PA) during a myocardial infarction?
- Activates plasminogen
- Dissolves blood clots that are blocking blood flow to the heart muscle
- Helps limit the extent of ischemic damage
55
What enzymes or other substances may serve as a marker for a heart attack?
- Cardiac creatine kinase (CK-MB)
| - Troponin I (TnI)
56
Why would elevated blood levels of troponin indicate heart damage?
If troponin escapes from the cell and enters the blood, this is an indication that the cell either has been damaged or is dead
57
What happens to contraction in a myocardial contracile cell if a wave of depolarization passing through the heart bypasses it?
- It will not contract
| - Failure to contract creates a non-functioning region of heart muscle and impairs the pumping function of the heart
58
What is the function of beta blockers (B1-adrenergic receptors) following a heart attack? What does it cause to an individual's heart rate?
- Decreases heart rate and lowers oxygen demand, which decreases chances of cells dying
- Antagonist to the B1-adrenergic receptors, which function to increase the heart rate
59
What are common symptoms of myasthenia gravis?
- Blurred vision
- Drooping eyelids
- Muscle weakness
60
What are the results of a conduction test and an electromyography test in individuals with mysthenia gravis?
- Conduction velocity is fine
- Muscle response decreased QUICKLY during repeated nerve stimulation
- Indicates that muscle response fatigued over time
61
What is the cause of myasthenia gravis?
- Autoimmune disease
- Antibodies block or destroy Ach receptors at the neuromuscular junction
- Prevents nerve impulses from triggering muscle contractions
62
How is end-plate potential influenced in myasthenia gravis?
Declines in amplitude as the disease progresses, until the nerves no longer produce an AP
63
What are treatment options for individuals with myasthenia gravis?
- The removal of the thyroid gland
| - Neostigmine (acetylcholinesterase inhibitor) allows a greater amount of Ach to accumulate in the synaptic space
64
What are possible symptoms that may arise from a tumor near the pituitary?
- Abnormal growth
- Joint swelling and the presence of sores
- Underweight
65
Why would joint damage be associated with rapid growth and low testosterone levels?
- Testosterone is involved in the hardening of bones during growth
- Damage to the joints is related to low cortisol
66
What is the Eric's primary problem? What are secondary problems?
- Pituitary gland has issues (primary)
- Thyroid gland isn't working (secondary)
- Testes didn't mature (secondary)
67
Why would Eric be infertile?
- Because he is taking replacement end-level hormones (testosterone)
- Spermatogenesis requires FSH
68
What may potentially be able to solve Eric's infertility?
hCG, which acts as LH to attempt to initiate spermatogenesis
69
What is acromegaly?
Joints continue to grow due to the increase in growth hormone in adulthood
70
Why does Eric urinate so often at night?
Because he does not make enough ADH, causing diabetes insipidus
71
Can you live without a pituitary?
- Yes, if you get replacement pituitary hormones (FSH, LH)
| - Yes, if you get replacement end-stage hormones (thyroid, testosterone)
72
What are signs and symptoms of Grave's disease?
- Fast heartbeat
- Poor tolerance of heat
- Diarrhea
- Unintentional weight loss
- EYE BULGING
- Enlarged thyroid
73
With blood doping, would you expect a hematocrit value to be lower or higher than normal?
Higher hematocrit to increase oxygen-carrying capacity
74
What is the molecular cause of sickle cell anemia?
- Glutamate is replaced by valine
| - Results in abnormal hemoglobin that crystallizes when it gives up oxygen
75
How does sickle cell anemia result in tissue damage and pain from hypoxia?
- Sickled cells become tangled with other sickled cells as they pass through smallest blood vessels
- The blockage creates tissue damage and pain from hypoxia
76
What is a treatment for sickle-cell anemia?
- Administration of hydroxyurea
- Compound that inhibits DNA synthesis
- Alters bone marrow function so that immature blood cells produce the fetal form of hemoglobin, instead of adult hemoglobin
77
What are hallmarks of a recent blood transfusion?
- Elevated hemoglobin
| - Elevated hematocrit
78
How might an individual, who has undergone blood doping, reduce his hematocrit without removing red blood cells?
- By drinking fluids, he would increase his plasma volume quickly
- If plasma volume increases, hematocrit will decrease even if RBC volume does not change
79
One hallmark of illegal EPO use is elevated reticulocytes in the blood. Why would this suggest greater-than-normal EPO activity?
- Reticulocytes are the final immature stage of RBC development
- If RBC development is more rapid, more reticulocytes may be released into the blood before they have time to mature
80
What occurs physiologically in a cleft palate?
- Palatine bones fail to unite completely
- Only partially separate the nose and mouth
- Produces difficulty in swallowing and speech
81
What are the causes of cleft palates?
- Genetic: mutant gene (trisomy 13)
| - Non-genetic: teratogenics (corticosteroids, benzodiazepines, and anticonvulsants)
82
Cleft palates result from a developmental defect due to decreased _________________.
migration of neural crest cells
83
What may be used to correct cleft palates?
Bone graft
84
How may you reduce the changes of cleft palates?
By taking a multivitamin with folic acid (48% reduction)
85
What is chronic obstructive pulmonary disease?
- Air exchange is impaired by narrowing of the lower airways
| - Most people with COPD have emphysema or chronic bronchitis, or both
86
What do patients with chronic bronchitis ressemble?
- "Blue bloaters"
- Bluish tinged skin (low blood O2 levels)
- Tendency to be overweight
87
What do patients with emphysema ressemble?
- "Pink puffers"
- Thin, have normal (pink) skin coloration
- Often breathe through pursed lips, which helps open their airway
88
What causes recurrent lung infections in cystic fibrosis?
- There is no solute movement from the ECF to the lumen
- Cilia become trapped in thick, sticky mucus and can no longer move
- Mucus cannot be cleared, and bacteria colonize the airways
89
Why do people with chronic bronchitis have a higher-than-normal rate of respiratory infections?
Bacteria trapped in the mucus can multiply and cause respiratory infections
90
What occurs in a pneumothorax?
- If the sealed pleural cavity is opened to the atmosphere, air flows in
- The bond holding the lung to the chest wall is broken, and the lung collapses, creating a pneumothorax (air in the thorax)
91
A victim has been stabbed in his left lung. Why does the left side of his rib cage seem larger than the right side?
- Loss of adhesion between the lung and chest wall would release the inward pressure exerted on the chest wall
- The rib cage would expand outward
92
Name the muscles that patients with emphysema use to exhale actively.
- Internal intercostal muscles
| - Abdominal muscles
93
Why would an individual with emphysema have an increased RBC count and hematocrit?
- Her arterial partial pressure of oxygen is low
- The major stimulus for RBC synthesis is hypoxia
- Triggers EPO release
3) Mammalian Physiology
flashcards
Decks in class (24)
# Cards
-
Lab 1: Histology188
-
Lab 2: Blood and the Immune System83
-
Lab 3: Heart Dissection, Recording and Interpreting ECG104
-
Lab 4: Renal Function44
-
Set 1198
-
Histology Slides72
-
Set 2114
-
Case Studies93
-
Set 3 (Part I)159
-
Set 3 (Part II)107
-
Set 4 (Part I)114
-
Set 4 (Part II)116
-
Set 5 (Part I)133
-
Set 5 (Part II)125
-
Set 6 (Part I)148
-
Set 6 (Part II)154
-
Set 7 (Part I)128
-
Set 7 (Part II)93
-
Set 8121
-
Set 9109
-
Set 10104
-
Set 11 (Part I)134
-
Set 11 (Part II)38
-
Histology34
