Human Physiology Exam 3 Quiz Questions

Partial pressure of oxygen dissolved in blood is 50 mm Hg. That means that

It would be in equilibrium with gaseous oxygen that is at partial pressure of 50 mm Hg

Molar concentration of dissolved gas …

Is found from the Henry law

The principle that diffusion is faster in gases than in liquids is important in the pathogenesis of

Pulmonary edema

The principle that larger alveoli are less efficient than small ones in supporting gas exchange is important in the pathogenesis of

Emphysema

What causes the expansion of lungs during inspiration?

Neither surface tension or connective tissue fibers

Match the left column (form of hemoglobin) to the right column (what causes it)

Carbaminohemoglobin 

Oxyhemoglobin

 Deoxyhemoglobin

 Methemoglobin              

 Carboxyhemoglobin

Carbaminohemoglobin: CO2

Oxyhemoglobin: Oxygen

 Deoxyhemoglobin: Absence of oxygen

 Methemoglobin: Fe3+              

 Carboxyhemoglobin: CO

Chloride shift is mediated by

Countertransport

Which hemoglobin would be most effective in transferring oxygen from alveoli with 120 mm Hg oxygen pressure to a tissue with 40 mm Hg oxygen?

B because at 120 mm Hg, all three types are saturated; at 40 mm Hg, type A has less oxygen bound than B or C, therefore it will release the largest amount of oxygen

Oxyhemoglobin has a higher affinity for CO₂ compared to deoxyhemoglobin

False

A defect in type 2 alveolar cells would mostly affect

Inspiration

What happens to hydrogen ions produced by carbonic anhydrase in erythrocytes?

Binds hemoglobin

Oxygen diffusion from the lungs into the tissue can be described by the equation: F = P(C_lung – C_tissue). Which of these parameters is most affected by convection (ventilation)?

 

C_lung

The main reason why hemoglobin increases the blood capacity for oxygen has to do with

High concentration of oxygen-binding sites provided by hemoglobin 

Why is alveolar P_O2 close to 100 mm Hg?

Because alveoli are located deep in the body

Henry’s constant for nitrogen is 6∙10^-4 M/atm. A diver dives to a depth where nitrogen partial pressure is 3 atm. What would be the nitrogen concentration in the diver’s blood at equilibrium in mmol/L? (Put the number without units)

1.8

Bulk flow is driven by differences in protein concentration

False

Choose the sentence that makes most sense.

If cardiac output is constant, then an increase in resistance would cause an increase in arterial pressure.

Indicate in each case, whether a given quantity is larger in veins or in arteries. Put “v” if it is larger in veins, “a” if it is larger in arteries, and “e” if it is equal for veins and arteries.

Compliance                                                           

Pressure                                                                 

Velocity of blood flow (centimeters per second)

Total blood flow (liters per minute)                         

Compliance: v                                                        

Pressure: a            

Velocity of blood flow (centimeters per second): a 

Total blood flow (liters per minute): e

What can be the cause of the plateau in the middle section of this curve?

Contraction of vascular smooth muscle

The relationship between cardiac output (CO), mean arterial pressure (AP), and total peripheral resistance (PR) is

AP = CO*PR

What maintains a relatively steady arterial pressure during the entire cardiac cycle? Choose the best answer.

Tension in the artery

When proteins escape from capillaries, edema may develop. This fact can be explained by

Increase in the colloid osmotic pressure of the interstitial fluid

How is lactate production in the muscle expected to affect local circulation?

Dilate arterioles

Hydrostatic pressure of blood = 50 mm Hg

Hydrostatic pressure of interstitial space = 0

Oncotic pressure of blood = 30 mm Hg

Oncotic pressure of interstitial space = 20 mm Hg

 

Calculate pressure balance. Put the number in mm Hg without units. Add a minus if the total pressure is directed into the capillary.

40

Calculate blood flow rate if the vessel cross section area is 1 mm² and blood velocity is 20 mm/s. (Keep in mind that 1 mm³ = 1 μl)

20 μl/s

This is a picture from a lecture. What would be the blood flow rate for d = 3? Put a number without units

81

Indicate the pressure range where Korotkoff sounds can be heard

Between a and c

The blockage of lymph flow may cause edema by

An increase in the interstitial oncotic pressure

Insert yes, if you agree, or no, if you disagree

Sympathetic neurons regulate arterioles:

Capillaries regulate arterioles:

Veins regulate arterioles: 

Sympathetic neurons regulate arterioles: yes

Capillaries regulate arterioles: no 

Veins regulate arterioles: no

Suppose you put a clamp on the end of a horizontal blood vessel, so that blood flow in that vessel stopped. What can we say about the pressure difference along this vessel?

Equal everywhere along the vessel

The Starling forces determine primarily the exchange of

Water

Which is the correct expression for baroreceptor sensitivity? Use Y for firing rate and X for arterial pressure.

dY/dX

At what point is baroreceptor sensitivity the highest?

B

The main reason for creating a high osmolarity in the medulla is to …

Facilitate water absorption from the collecting duct

What is the main mechanism of elimination by the kidneys of toxins contained in the blood plasma?

Toxins lack transporters in the tubules

Glomerular filtration is enhanced by the constriction of the afferent arteriole

False

The basolateral membrane is shown on the right

True

Inhibition of P-glycoprotein may cause

Accumulation of drugs in the organism

Reabsorption of glucose takes place in

Proximal tubule

Calculate the glomerular capillary blood pressure, if the oncotic pressure, the net glomerular filtration pressure and the pressure in the Bowman’s capsule are all 15 mm Hg. (Put just the number without units)

 

45

Hypertension can be treated by inhibitors of sodium reabsorption because…

Sodium increases the osmolarity of the plasma

 

This is a table from the lecture:

Why do the flow rates decrease in the more distal parts of nephron?

Water is reabsorbed

 

High osmolarity of the medulla is created by

 

Salts removed from the ascending loop of Henle

Destruction of the special cells that cover glomerular capillaries is likely to cause

Loss of protein

In which area of the kidney (1-6) are podocytes located?

1

Arrange the steps in logical order (starting with 1 and ending with 5) as they lead to passive absorption of urea in the proximal tubule:

1. Osmotic absorption of water

2. Import of Na⁺ from the apical side

3. Increase in the luminal urea concentration

4. Active pumping of Na⁺ by the basolateral Na⁺-K⁺ pump

5. Passive diffusion of urea into the epithelium

42135

Factors that cause vasoconstriction often exhibit a second effect. What is it?

Stimulation of sodium reabsorption

Where does the blood flow in the left capillary along the loop of Henle: up (1) or down (2)? 

2

What is the main purpose of the loop of Henle?

Conservation of water