Study Guide 4: Chapters 12, 13, 14 & 15 Flashcards

Flashcards for Chapters 12, 13, 14, and 15 focusing on key definitions and concepts related to skeletal muscles, reflexes, cardiac physiology, and blood pressure regulation.

Skeletal Muscles

Muscles attached to bones, responsible for movement; voluntary and striated.

Transverse Tubules (T-Tubes)

Invaginations of the sarcolemma that transmit action potentials deep into the muscle fiber.

Sarcomere

The basic contractile unit of a muscle fiber; includes A band, I band, H zone, and Z discs.

Latent Period

The time between the action potential and the beginning of muscle contraction.

Motor Units

A motor neuron and all the muscle fibers it innervates.

Effectors in a Reflex

Muscles or glands that respond to a stimulus in a reflex arc.

Reflex Arc

The neural pathway involved in a reflex action, including a receptor, sensory neuron, integration center, motor neuron, and effector.

Crossed Extensor Reflex

A contralateral reflex where one limb withdraws from a stimulus while the opposite limb extends to support the body.

Intercalated Discs

Specialized junctions connecting cardiac muscle cells, containing gap junctions and desmosomes.

End-Diastolic Volume (EDV)

The volume of blood in the ventricles at the end of diastole (relaxation).

Cardiac Output (CO)

The volume of blood pumped by each ventricle per minute (heart rate x stroke volume).

Starling's Law of the Heart

The greater the stretch on the heart muscle (increased EDV), the stronger the contraction.

Metarterioles

Short vessels that link arterioles and capillaries, regulating blood flow into capillary beds.

Angiogenesis

The formation of new blood vessels.

Mean Arterial Pressure (MAP)

The average arterial pressure throughout one cardiac cycle. MAP = diastolic pressure + 1/3(pulse pressure).

Pulse Pressure

The difference between systolic and diastolic blood pressure.

Osmotic (Oncotic/Colloid) Pressure

The pressure exerted by proteins in the blood plasma that tends to pull water into the circulatory system.

Baroreceptors

Pressure-sensitive receptors in the aortic arch and carotid sinuses that detect changes in blood pressure.

Excitation-Contraction Coupling

The sequence of events by which an action potential in the sarcolemma leads to the sliding of myofilaments.

Sliding Filament Theory

The mechanism of muscle contraction based on the sliding of actin and myosin filaments past each other.

Muscle Fatigue

Decline in muscle force and/or velocity resulting from previous contractile activity; caused by depletion of energy reserves, accumulation of metabolites, or failure of excitation-contraction coupling.

Isotonic Muscle Contraction

Muscle contraction that involves a change in muscle length (concentric or eccentric).

Isometric Muscle Contraction

Muscle contraction that involves no change in muscle length.

Autonomic Reflexes

Reflexes that involve involuntary responses of smooth muscle, cardiac muscle, or glands.

Somatic Reflexes

Reflexes that involve voluntary responses of skeletal muscles.

ECG Waves

P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization).

Heart Sounds

Sounds produced by the closing of the heart valves (S1: AV valves, S2: semilunar valves).

Isovolumic Contraction

Phase of ventricular systole when ventricles are contracting but volume is not changing.

Local Vasodilators

Substances that cause dilation of blood vessels in a specific area (e.g., K+, H+, CO2, adenosine).

Local Vasoconstrictors

Substances that cause constriction of blood vessels in a specific area (e.g., thromboxane A2, endothelins).

Active Hyperemia

Increased blood flow to a tissue due to increased metabolic activity.

Reactive Hyperemia

Increased blood flow to a tissue after a period of ischemia (e.g., after releasing a tourniquet).