Question

21 true or false 2 points
a vascular shunt allows blood to bypass capillaries by providing direct routes between arteries and veins.
true
false

22 multiple choice 2 points
choose the correct order and events for the steps of skeletal muscle contraction:

1. troponin changes shape and tropomyosin moves away from active sites; 2. calcium released from sarcoplasmic reticulum; 3. calcium binds troponin; 4. myosin heads bind to active sites, creating cross bridges
2. calcium released from sarcoplasmic reticulum; 2. calcium binds troponin; 3. troponin changes shape and tropomyosin moves away from active sites; 4. myosin heads bind to active sites, creating cross bridges
3. myosin heads bind to active sites, creating cross bridges; 2. calcium released from sarcoplasmic reticulum; 3. calcium binds troponin; 4. troponin changes shape and tropomyosin moves away from active sites

23 multiple choice 2 points
what is the resting potential inside a neuron?
+70 mv
-70 mv
+40 mv
0 mv
-40 mv

Explanation:

Analyze Question 21

A vascular shunt (metarteriole–thoroughfare channel) directly connects an arteriole to a venule, bypassing the true capillary bed.

$$ \text{Vascular Shunt} \implies \text{Arteriole} \to \text{Venule} \quad (\text{Bypasses Capillaries}) $$

Analyze Question 22

The physiological sequence of skeletal muscle contraction:

1. Calcium is released from the sarcoplasmic reticulum.
2. Calcium binds to troponin.
3. Troponin changes shape, moving tropomyosin away from the active sites on actin.
4. Myosin heads bind to the active sites, forming cross-bridges.

Analyze Question 23

The typical resting membrane potential of a neuron is approximately \(-70\text{ mV}\).

$$ V_m = -70\text{ mV} $$

Answer:

Question 21

• True (Correct answer)
• False

Question 22

• 1. troponin changes shape and tropomyosin moves away from active sites; 2. calcium released from sarcoplasmic reticulum; 3. calcium binds troponin; 4. myosin heads bind to active sites, creating cross bridges
• 1. calcium released from sarcoplasmic reticulum; 2. calcium binds troponin; 3. troponin changes shape and tropomyosin moves away from active sites; 4. myosin heads bind to active sites, creating cross bridges (Correct answer)
• 1. myosin heads bind to active sites, creating cross bridges; 2. calcium released from sarcoplasmic reticulum; 3. calcium binds troponin; 4. troponin changes shape and tropomyosin moves away from active sites

Question 23

• +70 mV
• -70 mV (Correct answer)
• +40 mV
• 0 mV
• -40 mV