Muscle Physiology Quiz

The cell membrane is primarily composed of two layers of lipids, forming a bilayer structure. It acts as a barrier between the cell's interior and the external environment.

Sodium (Na+) is the primary ion found outside of cells, in the extracellular fluid. It plays a critical role in maintaining osmotic balance and nerve impulse transmission.

Proteins embedded within the cell membrane perform various functions, including facilitating transport of molecules, acting as receptors for signaling, and catalyzing biochemical reactions.

Isotonic saline is a solution containing 0.9% NaCl, mimicking the concentration of salts in the body's fluids. It's used in medical settings to maintain fluid balance.

Glucose, a sugar, enters cells through a process called secondary active co-transport. This means it's coupled with the movement of sodium ions, which provides energy for transport.

The sodium-potassium pump is a protein that actively transports sodium ions out of the cell and potassium ions into the cell. This process requires energy and maintains the resting membrane potential.

Integral proteins are embedded within the cell membrane and play crucial roles in various functions, including transporting molecules, receiving signals, and facilitating chemical reactions.

The rate at which substances diffuse across the cell membrane is inversely proportional to the thickness of the membrane. Thicker membranes slow down diffusion.

A type of muscle contraction where the muscle length remains constant while tension increases. Think holding a heavy object.

The neurotransmitter involved in stimulating muscle contraction at the neuromuscular junction.

Fast skeletal muscle fibers are specialized for rapid, powerful contractions. They rely on glycolysis for energy production.

The principle that a single muscle fiber will contract completely or not at all, based on whether the stimulus exceeds its threshold.

Muscle fatigue is a decline in muscle performance due to factors like ATP depletion, glycogen depletion, and decreased blood supply.

The structural unit of a nerve is a neuron. It's the basic building block responsible for transmitting nerve impulses.

The outer layer of a myelinated nerve fiber is composed of Schwann cells, which wrap around the axon and provide insulation.

The resting membrane potential is caused by an unequal distribution of ions between the inside (ICF) and outside (ECF) of the cell. This difference in charge is essential for nerve function.

The absolute refractory period is a time when a nerve can't be stimulated again, regardless of the strength of the stimulus. This is due to the inactivation of sodium channels.

The Na+-K+ pump actively pumps sodium (Na+) ions out of the cell and potassium (K+) ions into the cell, maintaining the electrochemical gradient and resting membrane potential. It requires energy from ATP.

The local response is a graded potential that occurs in a localized area of the nerve fiber. It can be summed and is not subject to the all-or-none law.

The firing level, or threshold, is reached when the membrane potential reaches a specific voltage, typically around -55mV. This initiates the action potential.

The relative refractory period is a time when the nerve is less sensitive to stimulation, but can still be stimulated if the stimulus is strong enough. This is due to the partial inactivation of sodium channels and the opening of potassium channels.

The cell membrane is a selectively permeable barrier that surrounds cells. It's composed of a phospholipid bilayer, which acts as a barrier to many molecules, with embedded proteins that facilitate transport and communication.

Sodium (Na+) is the primary ion found outside of cells, in the extracellular fluid. It plays a crucial role in maintaining osmotic balance and nerve impulse transmission.

Proteins embedded within the cell membrane perform various functions, including facilitating transport of molecules, acting as receptors for signaling, and catalyzing biochemical reactions.

Isotonic saline is a solution containing 0.9% NaCl, mimicking the concentration of salts in the body's fluids. It's used in medical settings to maintain fluid balance.

Glucose, a sugar, enters cells through a process called secondary active co-transport. This means it's coupled with the movement of sodium ions, which provides energy for transport.

The sodium-potassium pump is a protein that actively transports sodium ions out of the cell and potassium ions into the cell. This process requires energy and maintains the resting membrane potential.

Integral proteins are embedded within the cell membrane and play crucial roles in various functions, including transporting molecules, receiving signals, and facilitating chemical reactions.

The rate at which substances diffuse across the cell membrane is inversely proportional to the thickness of the membrane. Thicker membranes slow down diffusion.

The myelin sheath is a fatty layer that covers nerve fibers. It allows for faster transmission of nerve impulses by reducing the resistance to ion flow. This allows the signal to travel quickly and efficiently.

Chronaxie is the minimum duration time required to stimulate a nerve when the intensity of the stimulus is twice the rheobase (minimum intensity needed for stimulation). It is a measure of nerve excitability.

The strength-duration curve shows the relationship between the strength (intensity) of a stimulus and the duration (time) required to elicit an action potential in a nerve fiber.

The resting membrane potential is the electrical potential difference between the inside and outside of a cell. It is typically negative (-70mV) and is maintained by the sodium-potassium pump.

The local response is a graded potential that occurs in the dendrites and cell body of a neuron. It is not an all-or-none response, meaning its amplitude can vary depending on the strength of the stimulus. It can summate with other local responses.

The absolute refractory period is a period after an action potential during which a nerve cell cannot generate another action potential, no matter how strong the stimulus.

An anelectrotonic response is a decrease in membrane potential caused by a decrease in the sodium ion concentration in the extracellular fluid. This leads to an increase in nerve excitability.

The local response in a single nerve fiber can be elicited by a cathode current of threshold intensity. It is associated with increased potassium permeability and is dependent on the intensity of the stimulus. If the membrane potential reaches a certain threshold level (-65mV), it can trigger an action potential.

During the resting state, the extracellular sodium concentration is higher than its intracellular concentration. This concentration gradient is maintained by the sodium-potassium pump and contributes to the resting membrane potential.

The body's response to cold temperatures involves the activation of the sympathetic nervous system, which triggers shivering and increased thyroid hormone secretion.

Heat stress causes the body to initiate vasodilation in skin blood vessels, leading to increased blood flow and heat dissipation.

Obesity is a condition characterized by excessive body weight, often caused by overeating and genetic predisposition. It increases the risk of gallbladder diseases.

Leptin, secreted by fat cells (adipocytes), plays a role in regulating appetite and food intake. It signals the brain to decrease hunger and decrease food consumption.

The average hydrostatic pressure in systemic capillaries is the pressure exerted by blood against the capillary walls.

The oncotic pressure is primarily determined by the concentration of plasma proteins, particularly albumin. These proteins attract water, pulling fluid into the bloodstream.

The capillary membrane is mainly impermeable to large molecules, such as proteins, which are too large to pass through the tiny gaps.

Lung compliance refers to the ability of the lungs to expand in response to changes in pressure. A normal compliance value is approximately 0.2 L/cmH2O.

Increased elastic forces within lung tissues, as seen in diseases like lung fibrosis, can increase the resistance of the lungs to inflation.

Emphysema, a condition that damages lung tissue, increases lung compliance due to the destruction of elastic fibers.

Scoliosis, fractured ribs, and paralysis of respiratory muscles can all decrease chest compliance by making it harder for the chest wall to expand.

The recoil tendency of the lungs is due to the elastic forces of the lung tissue and the surface tension of the fluid lining the alveoli.

Compliance of large blood vessels is a measure of their ability to stretch and expand in response to changes in pressure. Veins are more compliant than arteries because their walls are thinner and more elastic.

The pressure-volume curve of veins shows that a large increase in blood volume is associated with a relatively small change in pressure. This reflects their high compliance.

Activation of the sympathetic nervous system can decrease the compliance of blood vessels, making them less stretchy and reducing blood flow.