2015 physiology midterm

Question 1

The blood pressure of a patient increased. The baroreceptors sensed the increase and transmitted a signal to the cardiovascular center in the brain. This center then sent a signal to the heart in order to decrease the heart rate. What is the role of the heart in this homeostatic mechanism?

a) Effector
b) Sensor
c) Afferent pathway
d) Integrating center

Answer 1

a) Effector

Question 2

Which of the following subjects has the highest percentage of total body water?

a) A 20-year-old male
b) A 20-year-old female
c) A 40-year-old male
d) A 50-year-old female

Answer 2

a) A 20-year-old male

Question 3

A human normally ingests 2L of water daily. However, the same amount needs to exit the body in order to maintain homeostasis. Which organ is most responsible for this process?

a) Skin
b) Sweat gland
c) Liver
d) Kidney

Answer 3

d) Kidney

Question 4

More Na+ ions are present in the plasma than in the interstitial fluid. What is the reason behind that?

a) Na+ ions are too large to cross the capillary walls
b) Proteins in the plasma have a negative charge that attracts the Na+ ions
c) Proteins in the interstitial fluid have a positive charge that repels the Na+ ions
d) Na+ ions are required in the blood plasma

Answer 4

b) Proteins in the plasma have a negative charge that attracts the Na+ ions

Question 5

What is the osmolarity (mOsm/L) of a 5% glucose solution? (MW=180)

a) 277
b) 304
c) 312
d) 0.277

Answer 5

a) 277

Question 6

What is the osmotic pressure of the previous 5% glucose solution when placed in a semipermeable membrane having pure water on the other side?

a) 5867
b) 5346
c) 5.346
d) 6021

Answer 6

b) 5346

Question 7

compartment A= 1.5M of KCl
compartment B= 1.5M of NaCl
The membrane between compartment A and B is only permeable to Na+, what will occur?
a) Na will be equally distributed between the two compartments
b) Positive charges will be distributed equally between the two compartments
c) More positive charges will be accumulated in compartment B
d) More positive charges will be accumulated in compartment A

Answer 7

d) More positive charges will be accumulated in compartment A

Question 8

If ATP is hydrolyzed to carry substance against the concentration gradient, what mechanism of transport is this?

a) Facilitated diffusion
b) Primary active transport
c) Secondary active transport
d) Tertiary active transport

Answer 8

b) Primary active transport

Question 9

container A= 250 ml of 2% NaCl
container B= 500 ml of 0.9% NaCl
What is the final concentration after combining these 2 containers?
a) 2.1%
b) 2.7%
c) 1.2%
d) 1.7%

Answer 9

c) 1.2%

Question 10

Which of the following results in the reduction of the ICF osmolarity?

a) Excessive water intake
b) Loss of 1L of blood
c) Intravenous injection of 750ml 0.9% NaCl solution
d) Drinking sea water

Answer 10

a) Excessive water intake

Question 11

Which of the following results in the reduction of ICF volume?

a) Excessive water intake
b) Loss of 1L of blood
c) Intravenous injection of 750ml 0.9% NaCl solution
d) Intravenous injection of 400ml 2.4% NaCl solution

Answer 11

d) Intravenous injection of 400ml 2.4% NaCl solution

Question 12

Which of the following is the fastest mean of vesicle transport in a cell?

a) Movement along myosin I
b) Movement along actin filament
c) Facilitated diffusion
d) Movement along microtubule

Answer 12

d) Movement along microtubule

Question 13

During repolarization, the conductance of K+ ions decreased from 30Sn to 0Sn in a channel. Which gate was responsible for this decrease?

a) Inactivation
b) Deactivation
c) Activation
d) Inhibition

Answer 13

d) Inhibition

Question 14

Which of the following may cause insulin secretion?

a) Activation of ATP-sensitive K-channel
b) Hyperpolarization of the beta cells’ membrane
c) Inactivation of voltage regulated Ca-channels
d) Increase in ATP/ADP ratio

Answer 14

d) Increase in ATP/ADP ratio

Question 15

Repolarization of nerve cells occurs because of:

a) Influx of Na+ ions through gated sodium channels
b) Efflux of K+ ions through gated potassium channels
c) Efflux of K+ ions through sodium potassium leak channels
d) Influx of Cl- ions through gated chloride channels

Answer 15

b) Efflux of K+ ions through gated potassium channels

Question 16

What is the main reason for the cessation of neurotransmitter secretions in the presynaptic membrane?

a) Binding of the neurotransmitter to the presynaptic receptors
b) Accumulation of the neurotransmitter in the synaptic cleft
c) Synthesis of new neurotransmitter molecules
d) Influx of Na+ ions into the presynaptic nerve

Answer 16

a) Binding of the neurotransmitter to the presynaptic receptors

Question 17

In order for neurotransmitters to be released into the synaptic cleft, the level of intracellular Ca must increase. Where does the Ca come from?

a) Endoplasmic reticulum
b) Mitochondria
c) Vesicles
d) Extracellular fluid

Answer 17

d) Extracellular fluid

Question 18

Which of the following molecules is used by WBCs during an inflammation?

a) Cadherins
b) Integrins
c) Selectins
d) N-CAMs

Answer 18

c) Selectins

Question 19

A cell produced a certain chemical into the blood circulation in order to reach its target. What type of communication is this?

a) Paracrine
b) Autocrine
c) Neurocrine
d) Endocrine

Answer 19

d) Endocrine

Question 20

Which of the following describes peptide hormones?

a) Hydrophobic and bind to carrier proteins in plasma
b) Hydrophilic and attach to nuclear membrane receptors
c) Lipophobic and attach to plasma membrane receptors
d) Lipophobic and attach to nuclear membrane receptors

Answer 20

c) Lipophobic and attach to plasma membrane receptors

Question 21

Which of the following 2nd messengers mobilizes calcium from intracellular stores, such as the endoplasmic reticulum?

a) 3’5’-cyclic Adenosine Monophosphate
b) 3’5’-cyclic Guanosine Monophosphate
c) 1,2-diacylglycerol
d) Inositol 1,4,5-triphosphate

Answer 21

d) Inositol 1,4,5-triphosphate

Question 22

How is the cell affected in the presence of the cholera toxin?

a) Activation of Gi protein
b) Inhibition of adenylate cyclase
c) Decrease in cAMP levels
d) Increase in cAMP levels

Answer 22

d) Increase in cAMP levels

Question 23

Which of the following molecules can initiate the TGFβ/SMAD pathway?

a) Mullerian inhibiting factor
b) Growth hormone
c) Erythropoietin
d) Prolactin

Answer 23

a) Mullerian inhibiting factor

Question 24

Where is the thyroid hormone receptor located in a cell?

a) Bound to the nuclear membrane
b) Bound to the plasma membrane
c) Bound to the hormone response element on the DNA
d) Both in the cytoplasm and nucleoplasm

Answer 24

c) Bound to the hormone response element on the DNA

Question 25

What is the electric potential of a cell that has 15mM concentration of chloride ions inside and 150mM outside?

a) -61 mV
b) +61 mV
c) +49 mV
d) -49 mV

Answer 25

a) -61 mV

Question 26

What is the electric potential of a cell that has 35mM concentration of sodium ions inside and 120mM outside?

a) -32.6 mV
b) +32.6 mV
c) +56.4 mV
d) -56.4 mV

Answer 26

b) +32.6 mV

Question 27

Given that the concentration of a one-liter solution of CaCl2 is 111 osmol/L, what is the amount of solute present in this solution?

a) 42 moles
b) 34 moles
c) 11 moles
d) 37 moles

Answer 27

d) 37 moles

Question 28

A Subject has total body solutes of 18000 mOsmoles and osmolarity of 300 mOsm/L. What’s the osmolarity (mOsm/L) after equilibrium if we infuse 1L of 500 mOsm/L solute intravenously?

a) 320.3
b) 303.2
c) 298.4
d) 280

Answer 28

b) 303.2

Question 29

The concentration of Na inside the cell was 140, and outside the cell was 14, what is the membrane potential if only Na channels were open?

a) +61 mV
b) -61 mV

Answer 29

b) -61 mV