wsu biology 251 exam 3

in smooth muscle cells, calcium entering the cell first binds to ...; this complex in turn activates myosin light-chain kinase to initiate the contraction mechanism.

e. calmodulin

crossbridge cycling between actin and myosin in smooth muscle requires...?

d. the phosphorylation (activation) of myosin heads of the thick myofilaments by myosin light-chain kinase, thereby allowing them to bind with actin

which of the following most accurately lists the source of calcium required for the complete contraction of cardiac muscle cells?

c. calcium comes from both the extracellular fluid (ECF) surround the cells and from the sarcoplasmic reticulum (SR) of the muscle cells

what is the function of the sodium-calcium exchanger, i.e., a type of secondary active transporter in cardiac muscle cells?

d. to remove calcium from the cell by transporting it to the extracellular fluid (ECF), thereby relaxing the muscle

which of the following is NOT a part of the excitation-contraction coupling in cardiac muscle?

e. calcium binds to calmodulin in the cytoplasm to initiate contraction

what is the primary function of the heart valve?

a. to permit blood to flow forward through the heart while preventing it from flowing backward

where are pacemaker cells cells located in the heart?

d. both SA node and AV node

what phase of the cardiac cycle is the heart in when the aortic and pulmonary heart valves are open, and the ventricular pressure is sufficiently high to push blood out of the ventricles into the arteris?

b. ventricular ejection

pacemaker cells in the SA node receive nervous system input from ...?

c. both sympathetic and parasympathetic nervous system

in the heart, these structures allow electrical signals (action potentials) to pass from cells of the conduction pathway to the contractile cells, thus leading to their contraction.

e. gap junction

an increase in sympathetic nervous system input to the SA node of the heart would ... the heart rate (HR) leading to a(n) ... in cardiac output (CO).

c. increase : increase

which of the following is the correct conduction pathway for electrical signals through the heart, beginning where action potentials first originate?

d. SA node, AV node, bundle of His, Purkinje fibers

which of the following would increase the rate of blood flow through a blood vessel?

b. vasodilation of the vessel

which of the following components of an ECG represents ventricle depolarization?

d. QRS complex

a decrease in afterload, i.e. if blood pressure in the aorta falls, will lead to which of the following?

b. increased stroke volume (SV)

which of the following would decrease mean arterial pressure (MAP)?

b. a decrease in heart rate

the parasympathetic nervous system can decrease cardiac output (CO) by ...?

c. decreasing heart rate (HR)

which of the following causes vasoconstriction of arterioles, thus increases total peripheral resistance (TPR) and, therefore, increasing mean arterial pressure (MAP)?

e. all of the above would cause vasoconstriction of arterioles and increase MAP

an increase in cardiac output (CO), with no change in total peripheral resistance (TPR), would ...?

a. elevated mean arterial pressure (MAP)

an increase in total peripheral resistance (TPR), in the absence of any change in cardiac output, would ...?

c. elevate mean arterial pressure (MAP)

drugs that block angiotensin ii activity, i.e., angiotensin receptor blockers (ARBs), wold cause which of the following? remember our discussion in class.

a. decreased total peripheral resistance (TPR), and therefore, reduced mean arterial pressure (MAP)

the hormone vasopressin (also known as anti-diuretic hormone) acts to ...?

b. vasoconstrict arterioles, thus increasing total peripheral resistance (TPR)

as part of the baroreceptor reflex, which of the following would occur if arterial baroreceptors detect a lower than normal mean arterial pressure (MAP)?

b. the sympathetic nervous system would increase cardiac output (CO) and total peripheral resistance (TPR) to increase MAP

what is the volume of air moved into and out of the lungs in a single breath during unforced breathing called?

c. tidal volume (VT)

which of the following is NOT a function of the respiratory system?

b. maintain electrolyte balance of blood

according to Boyle's Law, what is the relationship between the volume of a gas and the pressure exerted by the gas?

b. the larger the volume of a gas, the lower the pressure of that gas

true or false, during inspiration, contraction of the diaphragmn results in an increase in volume of the intrapleural space, which lowers the intrapleural pressure, thus allowing the alveoli to expand.

a. true

in the lung, these cells engulf pathogens and debris such as dust or smoke particles that may reach the alveoli.

b. alveolar macrophages

the surface tension inside the alveoli is reduced by pulmonary surfactants produced by what type of cells?

d. type ii alveolar

the difference between what two pressures drives air into and out of the alveoli?

b. atmospheric pressure (Patm) and alveolar pressure (Palv)

in the lungs, which of the following occurs when alveolar pressure (Palv) is less than the atmospheric pressure (Patm)?

a. air moves from the atmosphere through the air passageways and into the alveoli

in a mixture of gases, the driving force for the diffusion of an individual gas within that mixture is ultimately the ...?

c. partial pressure of that individual gas in the mixture

during expiration (breathing out), elastic recoil of the alveoli causes their volume to decrease. this in turn causes their alveolar pressure (Palv) to ... and air moves ... the alveoli.

b. increase : out of

an increase in ventilation, i.e., an increase in minute volume, caused by input from respiratory chemoreceptors would lead to ... within the blood.

d. a decrease in CO2 and an increase in O2

during intense exercise, lactic acid produced in active muscles causes ... in the affinity of hemoglobin for oxygen, thus ... the release of oxygen into the active tissues; this response is known as the Bohr effect.

c. a decrease : increasing

how is most of oxygen transported in the blood?

b. bound to hemoglobin in red blood cells

central chemoreceptors are neurons in the brainstem that respond indirectly to changes in ...?

a. carbon dioxide (CO2) in the cerebrospinal fluid (CSF)

which of the following decreases the affinity of hemoglobin for oxygen, and therefore, increases the unloading of oxygen to tissues?

c. an increase in 2,3-DPG in red blood cells during anemia

how is most of the carbon dioxide (CO2) transported in blood?

d. as bicarbonate dissolved in the plasma

the enzyme carbonic anhydrase (CA) converts CO2 to carbonic acid to produce bicarbonate. in the blood, this reaction occurs in the ...?

a. red blood cells