Muscle Physiology and Cardiovascular System Review

Flashcards covering key concepts in Muscle Physiology and the Cardiovascular System.

The contractile organelle that runs the length of the myocyte is called __.

Myofibril

The __ is the functional unit of organization of the myofibril that gives the striated appearance.

sarcomere

Actin and myosin filaments interact during muscle contraction through the __ mechanism.

sliding-filament

The __ cycle describes the binding of myosin to actin, power stroke, and subsequent unbinding.

crossbridge

Acetylcholine (ACh) is released by somatic motor neurons to __ muscle contraction.

initiate

The gap between the axon terminal and the muscle fiber is called the __ cleft.

synaptic

Muscle fibers are innervated by __ motor neurons, which always activate them to contract.

somatic

The series of events that link the end-plate potential to muscle contraction is known as __-contraction coupling.

excitation

The enzyme responsible for breaking down ATP in the myosin head is called __.

ATPase

The __ mechanism of muscle contraction describes how muscles generate force while changing length.

isotonic

Muscle contractions that do not result in a change in muscle length are called __ contractions.

isometric

The __ principle refers to the recruitment of motor units in order from smallest to largest based on the force required.

size

During __, one twitch is not allowed to fully relax before another is produced, leading to increased force.

summation

The structural component of blood vessels that allows elasticity and distensibility is primarily due to __ and elastic fibers.

collagen

The pressure in the aorta during ventricular contraction is known as __ blood pressure.

systolic

The __ response occurs when blood flow is decreased to a tissue due to a prior increase in metabolic activity.

active hyperemia

The interactive relationship between venous pressure and blood volume is an example of the body's __ response.

homeostatic

Decreased oxygen concentration during local hypoxia acts to promote __ of arterioles.

vasodilation

Hormonal control of arteriolar radius can cause __ that increases blood pressure.

vasoconstriction

The two main factors impacting stroke volume (SV) include __ and afterload.

end-diastolic volume (EDV)

Alterations in heart rate (HR) and stroke volume (SV) occur simultaneously to impact __.

cardiac output (CO)

The __ layer, or epicardium, is the outer lining of the heart.

visceral

The __ system regulates blood flow and pressure through mechanisms like baroreceptor feedback.

nervous

The cross-sectional area of blood vessels facilitates faster exchange of materials in __.

capillaries

The formula for calculating mean arterial pressure (MAP) includes both systolic and diastolic blood pressures, specifically: MAP = DBP + 1/3(SBP - DBP).

True

muscle is responsible for voluntary movements and is characterized by striations.

Skeletal

The __ vessels serve as resistance vessels in the circulatory system, primarily affecting blood flow and pressure.

arterioles

The __ is a region of the sarcomere where thick and thin filaments overlap and is crucial for contraction.

A band

Increased contractility of the heart can be described by the __ law of the heart, which relates fiber length and strength of contraction.

Starling's