BMS 302 Exam 1

Resting membrane potential definition

measure of potential energy difference between the inside and outside of the cell membrane

Which ions are found in a greater concentration in the extracellular fluid than in the cytoplasm?

Na+ and Cl-

Which ions are found in a greater concentration in the intracellular fluid than in the extracellular fluid?

K+ and A-

What is the driving force dependent on?

concentration gradient and electrical gradient

The ability of a cell to generate an action potential is a measure of its

excitability

The ability of a cell to propagate an action potential is a measure of its

conductivity

How is the resting membrane potential of -70 mV (millivolts) best interpreted?

 

The inside of the fiber is 70 mV more negative than the outside

The resting cell membrane is permeable to:

K+ and Cl-

The resting cell membrane is impermeable to:

Na+ and A-

The concentration gradient for ______ is from the inside of the cell to the outside.

K+ and Anions

The concentration gradient for ______ is from the outside of the cell toward the inside.

Na+ and Cl-

The electrical gradient for ______ is from the outside of the cell to the inside.

Na+ and K+

Can all cells develop resting membrane potentials?

yes (and they do)

What types of cells can conduct action potentials?

smooth muscle cells, cardiac muscle cells, neurons, and skeletal muscle cells

During membrane depolarization, _________ move into the cell through _______ channels.

Na+, voltage gated channels

During membrane repolarization, ______ move out of the cell through _______ channels.

K+, voltage gated channels

What is the correct sequence of events leading to an action potential?

stimulus; depolarization; repolarization; Na+-K+ pump activity

What are four factors that can influence conduction velocity?

temperature, diameter, myelin sheath, pharmacologic agents

A compound nerve action potential is the result of:

The sum of electrical activity from all the neurons making up the nerve

When a higher stimulus than threshold produces a greater action potential in a compound nerve it is an example of what?

recruitment

Procaine….

Decreases conduction velocity, Decreases amplitude of compound nerve action potentials, Dissolves in the lipid rich neuronal membrane, Prevents Na+ voltage gated channels from opening when a neuron is stimulated

Physiology is defined as the branch of biology dealing with_______, while anatomy is the study of ________.

the functions and vital processes of living organisms; the morphology or structure of living organisms.

___________ neurons carry information toward the Central Nervous System, and _________ neurons carry information away from the Central Nervous System.

Efferent; afferent

Efferent or motor neurons conduct information to:

exocrine glands, skeletal, smooth, or cardiac muscle

What are some examples of effectors on the body?

muscles and glands

Which parameter in Ficks law of diffusion is the single most important factor in determining the rate of diffusion?

concentration gradient

Which parameter(s) are particularly important in determining the rate of diffusion across a cell membrane?

temperature, lipid solubility, surface area, and diffusion distance

Congo red's molecular weight is 697, methylene blue's is 320. Both were placed on the agar at the same time. The diameters are different because:

The solubility of congo red in agar is enough greater than that of methylene blue to overcome the fact that congo red has a greater molecular weight.

Sarcolemma

cell membrane surrounding the skeletal muscle cell

T tubules

system for rapid, efficient conduction of action potentials from cell surface to interior of muscle cells

Fiber

another name for cell when referring to muscle

Myofilament

elements involved in contraction, two type: actin and myosin

The movement of Ca⁺⁺ from the sarcoplasmic reticulum is via ______.

Passive transport and Simple diffusion

What event must occur before the myosin head detaches from the actin binding site during relaxation?

ATP combines with the myosin head in the low energy state.

What other event must occur for muscle relaxation to take place?

A calcium pump actively pumps Ca⁺⁺ back into the sarcoplasmic reticulum.

Muscles involved in "fine motor skills" will have _____ muscle fibers per motor unit than/as muscles involved in "gross motor skills".

fewer

Recruitment of motor units:

refers to more and more motor units contracting as the stimulus strength increases and results in a larger force of contraction

A very ____ allows skeletal muscle to respond to a subsequent stimulus before complete relaxation from the previous twitch and therefore a greater contraction is seen due to wave summation.

short refractory period

cholinergic definition

describes the neurons, neurotransmitters or drugs associated with the PANS

adrenergic definition

describes the neurons, neurotransmitters or drugs associated with the SANS

Describe the differences between the somatic, autonomic, sympathetic, and parasympathetic nervous system

the somatic nervous system (ONE neuron) controls voluntary movement through glands; the autonomic nervous system is divided into sympathetic, fight or flight, and parasympathetic, rest and repose

Describe the pathway of CNS to effectors in the PANS

Long preganglionic neuron releases Ach into ganglion and short postganglionic neuron releases Ach into effectors

Describe the pathway of CNS to effectors in the SANS

SHORT preganglionic neuron releases Ach into the ganglion and the long postganglionic neuron releases NE into effectors

What’s the difference in latent period between smooth and skeletal muscle?

skeletal muscle is 100x faster

ASK: The means of excitation for skeletal muscle is the

Somatic Nervous System

Rhythmic sub-threshold oscillations in membrane potential are called what?

slow wave potentials, a result of waxing and waning of sodium potassium pump

______ when the membrane potential reaches threshold in the visceral smooth muscle pacemaker cell.

Ca⁺⁺ voltage gated channels open

Describe the cholinergic agents used in lab

acetylcholine: agonist neurotransmitter, atropine: antagonist pharmacologic agent, pilocarpine: agonist

Describe the adrenergic agents used in lab

Epi: agonist hormone, NE: agonist neurotransmitter

Plasticity is the property of visceral smooth muscle that is seen when muscle fibers are stretched. Initially, stretch _______ muscle tone, followed by _______ in tone over time.

decreases; an increase

The actin:myosin ratio in smooth muscle is _____ that of skeletal muscle.

greater than

The ability of visceral smooth muscle to exhibit plasticity is the partly the result of:

unorganized arrangement of actin and myosin filaments.

As the fetus grows within the uterus, the fetus does not experience continual pressure because of the property of _______, which is characteristic of visceral smooth muscle cells.

plasticity