WorksheetsYear one Physiology Quiz
Total questions: 32
Worksheet time: 16mins
Which of the following transport mechanisms is most likely to exhibit "saturation kinetics" (Tmax)?
Simple diffusion through lipid bilayer
Facilitated diffusion of glucose via GLUT-4
Movement of water through aquaporins
Movement of oxygen into the pulmonary capillaries
In a cell with a resting membrane potential of -70mV, an increase in extracellular K^+ concentration would result in:
Hyperpolarization
Depolarization
No change in membrane potential
Increased driving force for K^+ efflux
The Na^+/K^+ ATPase pump is electrogenic because it:
Transports 3 Na^+ out and 2 K^+ in
Transports 2 Na^+ out and 3 K^+ in
Transports Na^+ and K^+ in equal ratios
Uses ATP to move ions down their concentration gradient
What is the primary determinant of the "Resting Membrane Potential" in most neurons?
The Na^+ equilibrium potential
The Ca^{2+} equilibrium potential
The K^+ equilibrium potential
The Cl^- equilibrium potential
During the absolute refractory period of a neuron, the inability to fire another action potential is primarily due to:
Opening of voltage-gated K^+ channels
Inactivation of voltage-gated Na^+ channels
The cell being in a hyperpolarized state
Low extracellular Ca^{2+} levels
Saltatory conduction occurs in myelinated fibers because:
Myelin increases the capacitance of the membrane
Voltage-gated channels are concentrated at the Nodes of Ranvier
Myelin decreases the length constant
The entire axon length is depolarized simultaneously
In skeletal muscle contraction, Ca^{2+} binds to which protein to initiate the cross-bridge cycle?
Tropomyosin
Troponin C
Troponin I
Myosin light chain
Which of the following is a characteristic of "Rigor Mortis"?
Increased ATP levels in the sarcoplasm
Lack of ATP preventing myosin dissociation from actin
Active pumping of Ca^{2+} into the sarcoplasmic reticulum
Relaxation of all muscle fibers
The "Triad" in skeletal muscle consists of:
Two Z-lines and one M-line
One T-tubule and two terminal cisternae
Two T-tubules and one terminal cisterna
One Myosin filament and two Actin filaments
Smooth muscle contraction differs from skeletal muscle in that it requires:
Binding of Ca^{2+} to Calmodulin
Troponin-Tropomyosin complex
Fast-acting Na^+ channels for depolarization
Absence of extracellular Ca^{2+}
Which plasma protein is the primary contributor to "Plasma Colloid Osmotic Pressure"?
Fibrinogen
Alpha-globulin
Albumin
Gamma-globulin
Erythropoietin (EPO) is primarily secreted by which cells in response to hypoxia?
Hepatocytes
Peritubular interstitial cells of the kidney
Red bone marrow cells
Splenic macrophages
A patient with Vitamin B12 deficiency is likely to show which RBC index profile?
Microcytic, Hypochromic
Macrocytic, Normochromic
Normocytic, Normochromic
Microcytic, Normochromic
In the "Extrinsic Pathway" of blood coagulation, the process is initiated by the release of:
Hageman Factor (Factor XII)
Tissue Factor (Factor III)
Platelet Factor 3
Thrombin
Which anticoagulant acts by inhibiting the action of Vitamin K epoxide reductase?
Heparin
Warfarin
Hirudin
EDTA
Which of the following is a feature of "Hereditary Spherocytosis"?
Increased surface area to volume ratio of RBCs
Defect in spectrin or ankyrin proteins
Resistance to osmotic fragility
Increased lifespan of RBCs
The primary function of "Neutrophils" in the innate immune response is:
Antigen presentation to T-cells
Antibody production
Phagocytosis and respiratory burst
Release of histamine and heparin
Which immunoglobulin is the only one capable of crossing the placenta?
IgA
IgM
IgG
IgE
Negative feedback loops are characterized by:
Amplification of the original stimulus
Moving the variable further from the set point
Reversing the direction of the initial change
Occurring only in pathological states
The "Total Body Water" of a 70kg male is approximately:
28 Liters
42 Liters
14 Liters
5 Liters
Which fluid compartment has the highest concentration of Magnesium and Phosphate?
Interstitial Fluid
Plasma
Intracellular Fluid
Transcellular Fluid
In the "G-protein coupled receptor" signaling, the alpha subunit possesses intrinsic activity to:
Phosphorylate proteins
Hydrolyze GTP to GDP
Synthesize cAMP
Open Ca^{2+} channels directly
"Accommodation" in a nerve fiber refers to:
Increase in threshold due to a slowly rising stimulus
Decrease in threshold due to repetitive firing
Exhaustion of neurotransmitter stores
Myelination of the axon
The velocity of conduction in a nerve fiber is directly proportional to:
The length of the axon
The diameter of the fiber
The intensity of the stimulus
The concentration of Cl^- ions
Which type of muscle fiber is characterized by high myoglobin content and high resistance to fatigue?
Type IIb (Fast glycolytic)
Type I (Slow oxidative)
Type IIa (Fast oxidative-glycolytic)
Type III (Fast oxidative)
In the NMJ, the enzyme "Acetylcholinesterase" is located:
Within the synaptic vesicles
On the pre-synaptic membrane
In the synaptic cleft/post-synaptic folds
Inside the muscle cytosol
What is the effect of "Hypocalcemia" on nerve excitability?
Decreases excitability by raising threshold
Increases excitability by lowering threshold
Has no effect on nerve tissue
Causes permanent hyperpolarization
Which component of the sarcomere stays constant in length during contraction?
I-band
H-zone
A-band
Sarcomere total length
The "Opsonization" of bacteria primarily involves which complement component?
C1q
C3b
C5b
C9
"Major Histocompatibility Complex (MHC) II" molecules are expressed on:
All nucleated cells
Only RBCs
Professional Antigen Presenting Cells (APCs)
Only T-cytotoxic cells
The "Plateau Phase" (Phase 2) of the ventricular action potential is primarily caused by:
Fast Na^+ influx
Efflux of K^+ through delayed rectifier channels
Influx of Ca^{2+} through L-type channels
Closure of Cl^- channels
According to the "Frank-Starling Law of the Heart":
Increased heart rate increases stroke volume
Increased end-diastolic volume increases stroke volume
Increased afterload increases cardiac output
Decreased venous return increases contractility
