BIOL 2160 Exam 4

Which of these is a single muscle cell?

muscle fiber

Where is the motor end plate located?

On the muscle cell membrane

Which event immediately results in a power stroke?

removal of inorganic phosphate

Which protein physically covers up myosin binding sites on actin?

tropomyosin

During an ______ twitch, the muscle actually shortens.

isotonic

Which type of muscle fiber will be darker in color?

oxidative

Where are Ryanodine receptors found?

on the SR membrane

During low intensity exercise, fatigue results from:

depletion of glycogen

During smooth muscle contraction, Ca2+ binds to:

calmodulin

When bound to ATP, myosin has a ____ affinity for actin.

low

Which valve allows blood flow into left ventricle?

mitral valve

Which is the only vein in the human body to transport oxygenated blood?

pulmonary vein

When pressure is lower in the left ventricles than in left atrium, the aortic semilunar valve will be:

closed

Where would you generally expect pressure to be higher?

pulmonary artery

Where would you expect CO2 levels to be higher?

systemic veins

Which channels allow cardiac pacemaker cells to reach threshold?

T-type voltage-gated calcium channels

When funny channels open, the cell's permeability to K+ goes:

down

Which of these is true during isovolumetric contraction?

atrial Pr < ventricular Pr < aortic Pr

Which phase is the only phase in which ventricular pressure is greater than aortic pressure?

phase 3

Where would you expect partial pressure for oxygen to be higher?

alveoli

Swallowing will cause the epiglottis to cover up the opening to the:

trachea

Which part of the respiratory tract functions most similarly to veins and arteries?

conducting zone

During inspiration, the diaphragm will be:

contracted

During expiration, the volume of the lungs:

decreases

If air pressure in a room = 700 mm Hg, and is 70% N, what is the partial pressure of N?

490 mm Hg

The partial pressure for Oxygen will be higher:

in systemic capillaries

Which of the following is a normal physiological response?

hypernea

Which of the following will result in blood CO2 levels that are too high?

hypoventilation

What does Ca-calmodulin bind to?

MLCK

Which of the following is missing in smooth muscle?

sarcomeres

What is the purpose of DHP receptors?

detect the action potential on T-tubules

Funny channels are permeable to:

both Na+ and K+

Why are action potentials so slow in contractile cells?

to establish a longer refractory period

Which of these changes most often?

alveolar pressure

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

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+ channels

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