PHYSIO Flashcards
During fetal placental circulation, fetal hemoglobin (HbF) will have a higher affinity to oxygen than maternal hemoglobin (HbA) because
A. HbA does not bind to oxygen efficiently at high pO2
B. HbF has a lower affinity to 2,3-BPG
C. HbF always exists in T state throughout fetal
life
D. HbA is a tetramer while HbF is a monomer
with a lower p50 value - both are tetramers. HbA is composed of 2 alpha and 2 beta, while HbF is composed of 2 alpha and 2 gamma
B HbF has a lower affinity to 2,3-BPG
This greater affinity for oxygen is explained by the lack of fetal hemoglobin’s interaction with 2,3-bisphosphoglycerate (2,3-BPG or 2,3-DPG). In adult red blood cells, this substance decreases the affinity of hemoglobin for oxygen. 2,3-BPG is also present in fetal red blood cells, but interacts less efficiently with fetal hemoglobin than adult hemoglobin. This is due to a change in a single amino acid (residue 143) found in the 2,3-BPG ‘binding pocket’: from histidine to serine, which gives rise to the greater oxygen affinity.
True about the alternate pathway of the complement system
A. Has C1 complex as the recognition unit
B. Begins with C3 for activation
C. Has C4b2a as its C3 convertase
D. Properdin inhibits the pathway
Begins with c3 for activation
**2019
True regarding omega-3 PUFAS
A. Sources include canola oil and corn oil - Omega-6
B. Shown to decrease both LDL and HDL-cholesterol
C. Help lower total cholesterol especially in hypercholesterolemic patients
D. Decrease serum triacylglycerols
Omega 3 FAs are found in oily fishes such as tuna, salmon, and mackerel Lowers LDL and TAGs
increases HDL
Omega 3 FAs are found in oily fishes such as tuna, salmon, and mackerel Lowers LDL and TAGs
increases HDL
A more negative membrane potential results in the opening of this channel A. Calcium B. Potassium C. Sodium D. Magnesium
Potassium
PISO
Potassium In Sodium Out
At resting membrane potential, the cell is negatively charged at -65 mV
K is an intracellular cation (positively charged). Opening of K channels will cause voltage K to move extracellularly following its concentration gradient, leaving the cell more negative
Na is an extracellular cation. Opening of Na channels will cause Na to move intracellularly following conc. gradient, making the cell positive
In the skeletal muscle, cross bridge formation between actin and myosin filaments results from:
A. Acetylcholinesterase action at the synaptic junction
B. Ryanodine receptor activation leading to dihydropyridine channels opening
C. Hydrolysis of ATP at SERCA
D. Calcium binding to troponin leading to
tropomyosin activation
D. D. Calcium binding to troponin leading to
tropomyosin activation
In the resting state, myosin is thought to have partially hydrolyzed ATP (state a). When promotes movement of tropomyosin on the actin filament such that myosin binding sites on actin are exposed. This then allows the “energized” myosin head to bind to the underlying actin (state b). Myosin next undergoes a conformational change termed “ratchet action” that pulls the actin filament toward the center of the sarcomere (state c). Myosin releases ADP and Pi during the transition to state c. Binding of ATP to myosin decreases the affinity of myosin for actin, thereby resulting in the release of myosin from the actin filament (state d). Myosin then partially hydrolyzes the ATP, and part of the energy in the ATP is used to recock the head and return to the resting state.
Work of breathing is increased in a/an:
A. Asthmatic patient with adequate airway resistance
B. Preterm 32 weeks infant with increased lung elastance
C. COPD patient with minimal bronchial secretions
D. Patient with anterior neck mass not in cardiorespiratory distress
B
A 34 year old night shift nurse was stabbed on his way to work. Post-operatively, he is hypotensive for the past 6 hours despite fluid resuscitation. Continuous ischemia will compromise this liver zone & affect: A. Detoxification B. Bile synthesis C. Degradation of ROS D. Distribution of O2 and nutrients
B. Synthesis
This will lead to an increase in GFR: A. Increased sympathetic stimulation B. Decreased renal blood flow C. Outflow obstruction D. Hypoproteinemia
Hypoprotenemia
makes sense cos increased in GFR pag may nephrotic syndrome
Hypoprotenemia
The increase in cutaneous blood flow when there is an increase in the activity of sympathetic cholinergic nerves is through a vasodilator substance called:
A. Bradykinin
B. Norepinephrine C. Nitric Oxide
D. Adenosine
A. bradykinin
What voltage-gated ion channel causes the relative refractory period? A. Na+ B. Cl- C. Ca2+ D. K+
D. K+
The Relative Refractory Period frequently extends well beyond phase 3. Even after the cell has completely repolarized (due to K+ channels). This characteristic of slow-response fibers is called Post-Repolarization Refractoriness.
What type of intracellular communication (signaling) is used by organisms during early tissue development? A. Paracrine B. Juxtacrine C. Autocrine D. Endocrine
Autocrine
Autocrine Signals often occurs during early development of an organism to ensure that cells develop into the correct tissues and take on the proper function. It is particularly important for self renewal of embryonic stem cells.
Type 1 respiratory failure is due to: A. Decreased respiratory muscle activity B. Increased dead space C. Impaired gas exchange D. Increased minute ventilation
A
Type 1 Respiratory Failure (Acute Hypoxemic Respiratory Failure) occurs with alveolar flooding and subsequent intrapulmonary shunt physiology. Alveolar flooding may be a consequence of pulmonary edema, lung injury, pneumonia, or alveolar hemorrhage.
A child goes on a ride at an amusement park. This ride spins him first in one direction and then in the other. When he steps off the ride, he staggers to regain his balance. The ride has activated which descending tracts making postural adjustments to changes in head position?
A. Tectospinal
B. Reticulospinal
C. Lateral vestibulospinal D. Corticobulbar
C
The Lateral Vestibular Tract ensures that different muscle groups are coordinated during postural control.
Which statement is true based on B the normal oxygen-dissociation curve
of hemoglobin and myoglobin?
A. Hemoglobin is a better oxygen transporter than myoglobin because it has a higher oxygen affinity
B. The oxyhemoglobin dissociation curve shifts to right as a consequence of Bohr effect & increased 2,3 bisphosphoglyceric acid
C. The p50 value increases when affinity of oxygen to both hemoglobin and myoglobin increases
D. The hyperbolic shape of the oxygen- myoglobin
dissociation curve reflects the positive cooperativity of oxygen binding of myoglobin
B
The causes of shift to right can be remembered using the mnemonic, “CADET, face Right!” for CO2, Acid, 2,3-DPG, Exercise and Temperature. Factors that move the oxygen dissociation curve to the right are those physiological states where tissues need more oxygen. For example, during exercise, muscles have a higher metabolic rate, and consequently need more oxygen, produce more carbon dioxide and lactic acid, and their temperature rises.
Which of these patients will C benefit from primary prevention of diabetes using medical nutrition therapy? A. Obese 47 year-old male with an HbA1c 7.5 percent B. 7 year old female with low C-peptide and insulin assay C. Bank executive with an FBS of 109mg/dL on routine annual examination D. Hypersensitive with normal BMI & 2 hour 75g post glucose load of 206 mg/dL
C - prediabetic
Which of these increase HDL A levels? A. saturated fatty acids B. w-3 PUFA in diet C. high TAG levels D. w-6 PUFA in diet
A
Saturated fatty acids - Increase LDL & HDL
w-3 PUFA in diet - Decrease TAG
High TAG levels - Decrease HDL
w-6 PUFA in diet -Decrease LDL and HDL
In patients with HIV/AIDS, weight D assessment is best evaluated in
terms of
D
Loss of lean body mass, without loss in overall body weight, a condition called cachexia, can adversely affect a person’s ability to function and recover from injuries and illnesses.
• It has been observed in patients with HIV, even when successfully treated with HAART.
• Whilst AIDS wasting in the pre-HAART ear was predominantly caused by reduced calorie intake and diarrhoea, weight loss in people receiving HAART is more subtle and less well understood.
