Muscle Tissue Composition and Types

<p>Aerobic fibers are associated with endurance (D)</p> Signup and view all the answers

<p>Type 2B (B)</p> Signup and view all the answers

<p>Related to endurance (C)</p> Signup and view all the answers

<p>Sarcomere (D)</p> Signup and view all the answers

<p>5-8 nm (C)</p> Signup and view all the answers

<p>There is no binding between myosin and actin. (A)</p> Signup and view all the answers

<p>2.18 um (B)</p> Signup and view all the answers

<p>It defines constants for muscle performance under various loads. (C)</p> Signup and view all the answers

<p>The time from action potential to tension development. (D)</p> Signup and view all the answers

<p>Capillaries (B)</p> Signup and view all the answers

<p>Enables mass transfer between blood and tissues. (A)</p> Signup and view all the answers

<p>The pulmonary circulation is low pressure and involves gas exchange. (B)</p> Signup and view all the answers

<p>Venules have a larger diameter than large arteries. (D)</p> Signup and view all the answers

<p>Pulse pressure decreases. (C)</p> Signup and view all the answers

<p>It diminishes buffering of the pressure pulse. (D)</p> Signup and view all the answers

<p>Arteries increase in stiffness and decrease in diameter. (D)</p> Signup and view all the answers

<p>Pulse wave velocity increases as you move distally from the heart. (D)</p> Signup and view all the answers

<p>Partial reflection of the pressure wave back towards the heart. (B)</p> Signup and view all the answers

<p>It is converted into heat and dissipated. (D)</p> Signup and view all the answers

<p>Blood velocity decreases and dissipates energy. (D)</p> Signup and view all the answers

<p>It is damped out. (D)</p> Signup and view all the answers

<p>Movement of tropomyosin on actin (A)</p> Signup and view all the answers

<p>The myosin head tips, pulling the actin filament (C)</p> Signup and view all the answers

<p>Myosin head binds to a new actin site after relaxation (C)</p> Signup and view all the answers

<p>Constant length with varying tension (A)</p> Signup and view all the answers

<p>Increased frequency can lead to fused tetanus (B)</p> Signup and view all the answers

<p>The time between action potential and contraction (A)</p> Signup and view all the answers

<p>Length, velocity, and time (D)</p> Signup and view all the answers

<p>Exposes actin-binding sites when bound with calcium (B)</p> Signup and view all the answers

<p>Induce tetanic muscle contraction (A)</p> Signup and view all the answers

<p>It aids in the cleavage of ATP (D)</p> Signup and view all the answers

<p>To contract and relax to alter flow resistance (A)</p> Signup and view all the answers

<p>It becomes less elastic and expands (A)</p> Signup and view all the answers

<p>Isovolumetric contraction (D)</p> Signup and view all the answers

<p>Increased stretch of ventricular muscles leading to greater contractile force (A)</p> Signup and view all the answers

<p>Tunica media (D)</p> Signup and view all the answers

<p>To relax or contract arteriole caliber (B)</p> Signup and view all the answers

<p>Volume when the mitral valve closes (A)</p> Signup and view all the answers

<p>Maximum pressure generated when the artery is open (D)</p> Signup and view all the answers

<p>Oscillatory flow (A)</p> Signup and view all the answers

<p>Pressure decreases (D)</p> Signup and view all the answers

<p>Increased pulse wave velocity and decreased distensibility (A)</p> Signup and view all the answers

<p>60% (B)</p> Signup and view all the answers

<p>Ovaries (A)</p> Signup and view all the answers

Muscle type attached to bones, enabling voluntary movement.

Muscle type found in internal organs, operating involuntarily.

Muscle type forming the heart, enabling the pumping action.

A muscle cell, containing myofibrils and sarcomeres (contractile units).

The functional unit of muscle contraction, composed of overlapping actin and myosin filaments.

Muscle fiber type producing ATP with oxygen, suitable for endurance activities.

Muscle fiber type producing ATP without oxygen, enabling fast contractions but leading to fatigue.

Mechanism where actin and myosin filaments slide past each other, shortening the muscle.

The force a muscle can generate is dependent on its length. Optimal force is generated at an intermediate length, where there's maximum overlap of actin and myosin filaments. Too short or too long leads to reduced force because of interference or lack of binding sites.

The length of a sarcomere where the muscle can generate maximum force. This is typically around 2.18 µm.

The speed of muscle contraction is inversely related to the load. A heavier load results in slower contraction, while a lighter load leads to faster contraction.

A mathematical model describing the load-velocity relationship of muscle contraction, relating external load, contraction velocity, and muscle properties.

The time lag between the arrival of a nerve impulse at a muscle and the beginning of muscle contraction, representing the delay in the excitation-contraction coupling process.

The elastic and damping properties of muscle tissue, influenced by the connective tissue surrounding muscle fibers, contributing to the delayed rise in tension.

The arrangement of blood vessels throughout the body, starting with large arteries and branching down to capillaries, where exchange of oxygen and nutrients occurs.

Pulmonary circulation carries blood to the lungs for gas exchange, while systemic circulation delivers oxygenated blood to the rest of the body.

Energy loss during blood flow due to friction between blood and vessel walls, and within the blood itself.

Arterial walls stretch and recoil, absorbing energy from the pressure pulse and smoothing blood flow. Reduced viscoelasticity leads to a less smooth pulse and higher pressure.

Arteries become stiffer and narrower further from the heart, due to changes in their structure.

The speed at which the pressure wave travels through arteries.

When arteries branch or change diameter, there's a change in resistance to the pressure wave (impedance), causing some of the wave to reflect back.

Reflected waves add to the original wave, increasing pressure in certain regions, especially distal arteries. This explains why systolic pressure can be higher in the periphery.

As blood flows through capillaries, energy is lost due to friction and branching, reducing the pressure wave and ensuring a smooth, continuous flow.

The pressure wave is gradually reduced as blood travels through capillaries, ensuring gentle and steady blood flow at the microvascular level.

The body's ability to adjust blood distribution to meet the varying needs of different tissues and organs.

The capillaries offer the greatest resistance to blood flow, primarily due to their small diameter.

Arterioles, the small arteries, control blood flow into capillary beds by adjusting their diameter.

The process of diverting blood away from less active areas (like cold feet) to regions with greater demand (like the vital organs).

Veins act as a reservoir, storing a significant portion of blood (~60% of total volume), providing a reserve in case of loss.

The aortic root, the section closest to the heart, expands with age as the aorta loses elasticity.

Pericytes (smooth muscle cells) surrounding arterioles regulate blood flow by contracting or relaxing to control vessel diameter.

The heart operates as two interconnected pumps (right and left sides) working in a series.

The heart pumps blood through two separate circuits: pulmonary (to lungs) and systemic (to body), with different pressure demands.

The heart can adapt its output (volume and pressure) based on demand, like during rest or exercise.

The heart's ability to increase its contractile force when stretched by increased incoming blood volume.

The heart is composed of specialized chambers: atria (holding) and ventricles (pumping), with valves regulating blood flow between them.

The heart's rhythmic cycle involves distinct stages: systole (contraction) and diastole (relaxation), each with specific changes in volume and pressure.

After ATP is cleaved into ADP and Pi, myosin heads tip, pulling the actin filament towards the center of the sarcomere.

Calcium ions (Ca2+) bind to troponin, causing a conformational change in tropomyosin, which exposes the myosin binding sites on actin.

When ATP binds to the myosin head, it causes the release of the myosin head from the actin binding site, allowing for muscle relaxation.

Isotonic twitches maintain constant tension while the muscle changes length, like lifting a weight. Isometric twitches maintain constant length while tension changes, like pushing against an immovable wall.

Increasing stimulation frequencies lead to greater contraction force. This is because subsequent muscle contractions build upon previous ones, achieving a sustained contraction.

The delay between the action potential arrival and the start of muscle contraction, reflecting the time required for excitation-contraction coupling.

A sustained muscle contraction achieved by repetitive muscle stimulation at sufficiently high frequencies (>30Hz), representing the physiological muscle contraction mode for real life activities.

The tension generated during muscle contraction depends on the muscle's length, the velocity of the contraction, and the time of the contraction.

At the optimum length, there is maximal overlap of actin and myosin filaments, allowing for maximum cross-bridges to form and thus maximal force generation.

As the load increases, the velocity of muscle contraction decreases. This is known as the load-velocity relationship, a fundamental principle in muscle mechanics.