Physiology Practice Exam Review: Neuromuscular, Cardiovascular, and Respiratory Systems

Flashcards covering key physiological concepts across autonomic control, muscle mechanics, cardiac electrophysiology, hemodynamics, and comparative respiratory strategies.

Parasympathetic Bronchiole Response

The constricting of lung bronchioles occurring when an organism is in a parasympathetic dominant state.

Sympathetic Pancreatic Response

The autonomic response where the pancreas causes glucose to be released in a sympathetic dominant state.

Parasympathetic Digestive Motility

The increase in digestive tract motility that occurs during a parasympathetic state.

Acetylcholine (Autonomic Role)

The primary neurotransmitter utilized more abundantly by an animal when it is in a relaxed state.

Autonomic Dominance Shifting

The ability of an organism to switch between sympathetic and parasympathetic states using sensory information, internal mental state, and conscious choice or control.

Tract

A group of axons following the same pathway located within the central nervous system.

Nerve

A group of axons following the same pathway located within the peripheral nervous system.

Withdrawal Reflex Interneurons

A neural circuit arrangement in the withdrawal reflex where excitatory and inhibitory interneurons are paired together.

Dihydropyridine Receptors

Receptors in skeletal muscle whose decrease in quantity causes a decrease in muscle contraction rate.

T-tubules (Transverse Tubules)

Invaginations that spread the action potential throughout skeletal muscle fibers.

Superfast Muscle Adaptations

Specializations that include an increased number of mitochondria and a larger sarcoplasmic reticulum, but do not include an increase in myoglobin content.

Myosin Light Chain Kinase (MLCK) Activation

The mechanism triggering smooth muscle contraction when MLCK phosphorylates regulatory light chains located on the myosin head.

Fast-Glycolytic Fibers

The specific skeletal muscle fiber type most heavily relied upon when training for power lifting.

Actin (Activation State)

The contractile protein component that does not transition from an inactive to an active state during muscle contraction.

Calsequestrin and Ryanodine

Molecules and channels that actively regulate the release of $Ca^{2+}$ within muscle tissue.

Tonic Smooth Muscle

Smooth muscle whose sustained contraction is primarily regulated by the intracellular $Ca^{2+}$ level rather than action potentials.

Phasic Smooth Muscle

Smooth muscle whose rhythmic contraction is primarily triggered and regulated by action potentials.

Muscle Elasticity Hierarchy

The relative ranking of muscle tissue types from most elastic to least elastic: smooth muscle (most), cardiac muscle, and skeletal muscle (least).

Relaxed Muscle Fiber State

The structural state where the myosin cross-bridge binding site on actin is physically covered by the troponin-tropomyosin complex.

Twitch Summation Determinant

The relative timing of motor neuron action potentials that determines whether successive muscle twitches summate.

Neuromuscular Junction End Plate Potential

The graded potential produced at the motor end plate mediated by the neurotransmitter acetylcholine.

Voltage-Gated $Na^+$ Channels (Muscle)

The channels in muscle tissue that open first following an incoming action potential at the neuromuscular junction.

Tetanus

The phase of muscle twitch characterized by a sustained, maximal contraction without relaxation.

Coronary Arteries

The arterial blood vessels responsible for delivering oxygenated blood directly to the heart muscle itself.

Venous Return Aids

Physiological mechanisms that facilitate blood returning to the heart, including valves and the skeletal muscle pump, but excluding highly elastic vessel walls.

Decreased Extracellular Cardiac $K^+$

An electrolyte imbalance around cardiac tissue that causes repolarization to proceed faster.

Decreased Extracellular Cardiac $Na^+$

An electrolyte disturbance around cardiac tissue that leads to a decrease in heart rate.

Increased Extracellular Cardiac $Ca^{2+}$

An alteration in myocardial extracellular fluid that causes the cardiac action potential plateau phase to lengthen.

T-type $Ca^{2+}$ Channels (Cardiac)

Cardiac pacemaker channels whose accelerated or premature opening causes heart rate to increase.

Mammalian Cardiac Conduction Pathway

The sequential electrical pathway in the heart progressing: SA node, AV node, Bundle of His, then Purkinje fibers.

Prostacyclin and Nitric Oxide

Endothelial-derived factors in hemostasis that directly prevent the growing platelet plug from becoming excessively large.

Norepinephrine Channel Targets

Cardiac ion channels acted upon by norepinephrine, including funny $Na^+$ channels (HCN channels) and L-type $Ca^{2+}$ channels, but not $K^+$ channels.

Platelet Plug Recruitment

The activation and aggregation cascade during hemostasis that operates via positive feedback.

Hypercapnic Vasodilation

The widening of blood vessel lumen triggered by increasing carbon dioxide levels in the local blood supply.

Peripheral Resistance

Vascular resistance whose increase directly results in an increase in mean arterial pressure (MAP).

Parasympathetic Cardiac Limitation

The consequence of isolated parasympathetic innervation of the heart, resulting in the loss of regulation over stroke volume.

Pleural Cavity

The fluid-filled anatomical space that prevents the lungs from collapsing by maintaining negative intrapleural pressure.

Pulmonary Surfactant

A surface-active lipoprotein complex that functions to equalize surface tension among alveoli of differing diameters.

Countercurrent Gas Exchange

An efficient respiratory mechanism in aquatic organisms that maintains a relatively constant partial pressure gradient across the entire exchange surface.

Piscine Heart Oxygenation

The circulatory characteristic of fish hearts, which contain exclusively deoxygenated blood.

Bohr Effect (Low pH)

The physiological phenomenon where lower, more acidic pH decreases the binding affinity of hemoglobin for oxygen.

Mammalian Gas Exchange Efficiency

A comparative respiratory characteristic showing mammals to have the least efficient gas exchange system when compared to birds and fish.

Alkaline Blood Respiratory Response

The respiratory reflex where blood becoming more basic or alkaline leads to a lowering of the breathing rate.

Chloride Shift ($Cl^-$)

The ionic exchange process wherein chloride is utilized to transport $HCO_3^-$ across red blood cell membranes.

Chelonian Ventilation

The breathing mechanism seen in turtles that utilizes limb movements to aid ventilation within a rigid shell.

Ram Breathing

A forward-motion ventilation strategy that expends the least amount of active energy, representing the most energetically efficient breathing method.