Fundamentals of Anatomy and Physiology Ch. 10 Pt 3

What is hypertrophy?

An enlargement of the stimulated muscle; (an increase in tissue size without cell division)

What is an example of white muscles?

Chicken breasts contain "white meat" because chickens use their wings for only a short amount of time.

What is an example of red muscles?

Chicken legs contain "red meat" because chickens walk around all day.

What's the difference between fast and slow fibers?

Slow fibers have only about 1/2 the diameter of fast fibers and take 3x as long to reach peak tension after stimulation

What is a main characteristic of slow muscle fibers?

They are surrounded by a more extensive network of capillaries than is typical of fast muscle tissue, therefore they have a significantly higher oxygen supply to support mitochondrial activity

What do smooth muscles do around blood vessels?

They regulate blood flow through vital organs

What are slow fibers specialized to do?

They're specialized to enable them to continue contracting for long periods. (long after a fast fiber would've fatigued; this shows an improvement of mitochondrial performance in slow fibers)

What is atrophy?

When the muscle becomes flaccid, and the muscle fibers become smaller and weaker, a reduction in muscle size, tone, and power.

Why do fast fibers fatigue rapidly?

because their contractions use ATP in massive amounts. (and there are a few mitochondria to generate ATP.)

What's an example of muscular hypertrophy?

bodybuilder

What are most of the muscle fibers in the body called?

fast fibers; because they can reach peak twitch tension in 0.01 sec or less after stimulation

Where are cardiac muscle cells found?

only in the heart

What do muscles dominated by fast fibers produce?

powerful contractions

What are muscles dominated by fast fibers which often appear pale called?

white muscles

Structural Characteristics of Smooth Muscle Tissue:

-Cardiovascular System: regulate the flow of blood to the superficial dermis -Respiratory System: smooth muscle contraction or relaxation alters the diameters of the respiratory passageways and changes the resistance to airflow -Digestive System: Extensive layers of smooth muscle in the walls of the digestive tract play a vital role in moving materials -Urinary System: Smooth muscle tissue in the walls of small blood vessel alters the rate of filtration in the kidneys. Layers in the walls transport urine to the bladder; forces urine out -Reproductive System:Layers of smooth muscle help move sperm along reproductive tract in males and cause ejection of glandular secretions from accessory glands into reproductive tract. In females, oocytes move along tract and contraction expels the fetus at delivery

Structural Characteristics of Cardiac Muscle Tissue:

-contain organized myofibrils -aligned sarcomeres, therefore striated -relatively small -single, centrally placed nucleus (with some exceptions) -myocytes are usually branched -T tubules are short and broad, no triads -the T tubules encircle the sarcomeres at the Z lines -the SR lacks terminal cisternae, and its tubules contact the plasma membrane and T tubules -almost totally dependent on aerobic metabolism to obtain energy they need to continue contracting -contracts several others at specialized sites (intercalated discs)

What are characteristics of fast fibers?

Fast fibers are: large in diameter and contain densely packed myofibrils, large glycogen reserves, and a few mitochondria.

What do smooth muscle tissue form?

It forms sheets, bundles, or sheaths around other tissues in almost every organ.

Where does hypertrophy occur?

It occurs in muscles that have been repeatedly stimulated to produce near-maximal tension

What are muscles dominated by slow fibers known as?

red muscles; (because the extensive blood vessels and myoglobin (red pigment) give slow fibers a reddish color)

What are intercalated discs?

specialized sites where each cardiac muscle cell contacts

What happens at an intercalated disc?

the plasma membranes of two adjacent cardiac muscle cells are extensively intertwined and bound together by gap junctions and desmosomes.