Biol 2160 exam 4

A genetic mutation that destroys SERCA pumps in skeletal muscle cells might have which of the following consequences?

Inability to relax skeletal muscle

At the neuromuscular junction, the end plate potential occurs:

On the skeletal muscle cell membrane

Blood leaving the legs and traveling to the heart will be carried by:

The Inferior Vena Cava

Compared to cardiac muscle, action potentials in skeletal muscle are:

Shorter in duration

During inspiration, alveolar pressure is __________ atmospheric pressure.

less than

During isovolumetric contraction:

Aortic pressure > Ventricular pressure > Atrial pressure

During ventricular filling, you would expect the mitral valve to be:

open

During ventricular ejection:

Ventricular pressure > aortic pressure

Low intensity exercise will most likely result in an increase in ___________ fibers.

Oxidative

If phosphatases stopped being produced, the duration of smooth muscle contraction would be much:

longer

If the tricuspid valve failed to open:

Blood could not flow from the right atrium to the right ventricle

In smooth muscle cells, what does Ca2+ bind directly to?

Calmodulin

Myosin has the highest ainity for actin when the myosin head is bound to:

ADP + Pi

Patent Ductus Arteriosus (PDA) is the result of which two blood vessels remaining connected aer birth?

Aorta and Pulmonary Artery

Pulmonary ventilation occurs:

In the lungs

Smooth muscle forms crossbridges.

True

The blood that undergoes systemic circulation is pumped by:

the left side of the heart

The nicotinic acetylcholine receptor is:

Equally permeable to Na+ and K+

The partial pressure for oxygen in the alveoli is ________ than the partial pressure for oxygen in pulmonary capillaries.

greater

The partial pressure for carbon dioxide in tissues is _______ than the partial pressure for carbon dioxide in systemic capillaries.

greater

The partial pressure of CO2 is higher in systemic arteries than it is in systemic veins.

false

The purpose of DHP receptors in skeletal muscle is to:

Detect action potentials along t-tubules

The purpose of pulmonary ventilation is to:

Create pressure gradients between alveolar air and atmospheric air

The force of the heartbeat is due to the activity of:

Contractile cells

Which type of muscle fibers will be darker in color?

Oxidative

Which of these is the thin, fiber-like protein that physically covers up the myosin-binding site on actin when Ca2+ levels are low?

Tropomyosin

Which of these is Calcium-sensitive?

Troponin

Which of these is a condition in which breathing does not meet the demands of the tissues?

Hypoventilation

Which event directly cocks the myosin head?

ATP hydrolysis

Which channel type is NOT opened before threshold?

L-type Voltage-gated Ca2+ channels

Which channel type allows the membrane potential of cardiac pacemaker cells to reach threshold?

T-type Ca2+ channels

The t-tubule is part of the:

Muscle cell membrane

Which channel is responsible for the stimulus that opens HCN channels in cardiac pacemaker cells?

Voltage-gated K+ channels

The three factors that determine air flow are: atmospheric pressure, alveolar pressure, and resistance. Which of these changes most often?

Alveolar pressure

Where would you expect pressure to typically be highest?

Arteries

The bicuspid valve:

Controls blood flow into the le ventricle

Where is the motor end plate found?

On the muscle cell

The valve separating the pulmonary vein from the le atrium is which type of valve?

There is no valve separating the pulmonary vein from the le atrium

Where does the majority of Ca2+ needed for smooth muscle contraction come from?

Outside the cell

The Vena Cava:

Carries deoxygenated blood to the heart

Voltage-gated Na+ channels inactivate during the cardiac pacemaker cells action potential.

True

Where does conduction of action potentials slow?

AV node

When would you expect the bicuspid valve to be closed?

When pressure in the le ventricle is higher than pressure in the left atrium

What determines whether a fiber is fast twitch or slow twitch?

How quickly the myosin head can hydrolyze ATP

When the diaphragm contracts:

Pressure in the lungs decreases

What is accomplished with the removal of the inorganic phosphate (Pi) during skeletal muscle contraction?

It begins the power stroke

What would happen if atmospheric air pressure were to suddenly drop?

Oxygen would flow out of your lungs very quickly

What is the main structural difference between the conducting zone and the respiratory zone?

The respiratory zone has thinner walls

What would be the consequence of the aortic semilunar valve not closing properly?

Oxygenated blood would flow from the aorta to the left ventricle

What is the purpose of L-type Ca2+ channels in contractile cells?

To ensure a long refractory period for the contractile cells

During skeletal muscle contraction, Ca2+ binds directly to ______________.

Troponin

DHP receptors are found

T tubules

ATP hydrolysis results immediately in:

cocking of the myosin head

______________ fibers will be darker in color.

oxidative

When bound to ATP, myosin will have a __________ affinity for actin.

low

During isovolumetric relaxation, pressure is higher in the __________.

Ventricles

During ventricular ejection, pressure in the ventricles will be _______________ than pressure in the aorta.

higher

What is the stimulus that OPENS funny channels?

Hyperpolarization

Which valve prevents back flow of blood into the left atrium?

Bicuspid valve

Which channel type allows for long duration action potentials in contractile cells?

L-type Ca2+ channel

During inhalation, the diaphragm will be:

Contracted

The partial pressure for CO2 will be ____________ in tissue cells than in systemic capillaries.

higher

When breathing exceeds the demands of the tissues, this is called _______________.

Hyperventilation

True or False:There is more oxygen in alveoli than there is in pulmonary capillaries.

true

Relaxing the diaphragm causes pressure in the lungs to ______________.

increase

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