Midterm Practice

The rate of Ca+ diffusion across a membrane is dependent on -

Na+ concentration on either side of a membrane plays a role in osmolarity, even if it is not permeable to the membrane.

The rate of diffusion for a solute across a membrane is dependent on -

Homeostasis in physiological systems refers to the maintenance of a static or constant conditions in the internal environment.

Influences on receptor-mediated channels refers to a protein

Osmotic pressure is the pressure necessary to allow the movement of water across a membrane.

Secondary active co-transporter proteins in a cell membrane have which of the properties listed below?

Which statement below is NOT true?

Active transport differs from facilitated diffusion in that it uses energy to move a substance uphill against its concentration gradient.

The equilibrium potential for a particular ion is the voltage in which that ions movement across a lipid membrane comes to a relative stop.

Depolarizing the membrane of excitable cells by ~10mV will initiate -

The Nernst Equation is important for:

When determining the "equilibrium potential" for Na+, we have to assume the membrane is permeable to Na+.

Which channel is most responsible for the depolarization phase of an action potential across a cell membrane?

Which process listed below is most responsible for maintaining the electrochemical gradient?

What two factors make using the Goldman Equation more appropriate for determining the "Resting Membrane Potential", instead of using the Nertz Equation?

Which ion is most responsible for the initial change (depolarization) in membrane potential during the action potential?

Ligand-gated channels are important for initiating an action potential at the neuromuscular junction.

Slow, oxidative muscle fibers -

The sarcoplasmic reticulum stores __________ when a muscle is relaxed and releases it for binding to _______ during contraction.

Put in to the correct sequence the following events involved in muscle cell contraction. 1. Voltage-gated sodium channels open, allowing sodium to flow in. 2. Spreading action potential reaches T-Tubles activating a DHP molecule. 3. Acetylcholine binds to receptors on muscle cell membrane. 4. Ligand-gated receptors allow small amounts of sodium into the cell changing membrane potential 10mV(+). 5. If enough sodium moves into the muscle cell, an impulse (action potential) develops.

Which molecule listed below is responsible for "physically" inhibiting the binding of the myosin head to the active binding site on actin?

In order to allow discrete events to occur, calcium is rapidly removed from the cytoplasm by __________.

When an action potential is generated within a motor unit -

The releasing of Ca++ inside the skeletal muscle cell (intracellular) is initiated by which protein receptor listed below?

The t-tubules are an extension of the cell membrane of the skeletal muscle cell.

The t-tubule of cardiac muscle

The fusing of synaptic vesicles with the terminal button membrane is initiated by Ca++ influx into the cell.

The plateau of the cardiac action potential results from opening of voltage-gated, slow _______ channels in the membrane of the cardiac cell.

Heart muscle has long refractory period due to extended K+ channel opening.

Increased activity within the parasympathetic nervous system will result in changes primarily within the

Which of the following is NOT involved in triggering the normal coordinated contraction of cardiac muscle cells?

The long refractory period of cardiac muscle prevents tetanic contraction of the heart.

The sinoatrial node requires external stimulation in order to generate an action potential.

Which of the following EKG events represents the depolarization of the ventricle?

The spontaneous action potential generated by the Sino-Atrial Node, Atrio-ventricular Node, and Purkinje Fibers is due to K+ leaking across the cardiac muscle cell membrane.

The depolarization of the atria (by the Sino-Atrial Node) will be communicated (sent) to the ventricles (Purkinje fibers) by the _________.

Diastolic pressure generated by the right ventricle must overcome pressure in the aorta to get blood flow out to the rest of the body.

The Frank-Starling mechanism of heart contraction state that as more blood enters the heart, the heart will respond by contracting with greater force. Which is the statements below helps explain how this works?

Contraction of motor units is a(n) ____________ manner allows a muscle to maintain a level of force for a duration of time without fatiguing.

Skeletal muscle fibers operate at near-optimal sarcomere length in the normal individual.

The speed at which the action potential travels through different parts of the heart conduction system is dependent on -

The influx of calcium into the axon terminal of a chemical synapse is responsible for the ____________.

Which substance below could be used to treat 'flaccid paralysis'?

Pressure in the right atria of the heart is ~0

Ventricular cardiac muscle cells demonstrate a stable resting membrane potential with no evidence of the slow depolarization of the specialized cardiac pacemaker cells.

Which specialized muscle tissues of the heart can generate the greatest number of action potentials in a minute?

An ion's overall electrochemical gradient will tend to force that ion across the membrane in a direction that will cause membrane potential to move toward that ion's equilibrium potential.

The electrical potential of a membrane at rest is closest to potassium's equilibrium potential because ___________.

As a consequence of Frank-Starling's Law of the heart, _________________________.