Biology 2404 Chapter 6
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Biology 2404 Chapter 6
What is the essential function of muscle tissue?
Contraction or Shortening
Identify the three types of muscle tissues?
Smooth, Skeletal, and Cardiac
What specifically is a muscle "fiber"?
A Muscle Cell
What do the prefixes "myo-", "mys-", and "sarco-" indicate?
Describe the general shape of a Skeletal Muscle Fiber?
Elongated, Blunt Ends
What does "striated" imply about the appearance of a Skeletal Muscle fiber?
Fibers have obvious stripes perpendicular to the long axis.
As a "voluntary" muscle how is a skeletal muscle unique compared to smooth and cardiac muscle?
It is the only muscle type subject direct conscious controll.
Describe the skeletal muscle in regard to its general speed of contraction, ablitiy to deliever force, and ability to maintain contraction and force?
General speed of contraction
Ablitiy to maintain contraction and force
Define and locate Endomysium?
Wraps each muscle fiber.
Define and locate Perimysium?
Wraps around a bundle of muscle fiber within a organ.
Define and locate Epimysium?
Covers entire muscle organ.
What is a fascicle and which connective tissue sheath surrouds each single fascicle?
Bundle of muscle fibers within a muscle organ: surrounded by a perimysium.
Distinguish between epimysia, tendons, and aponeuroses?
: capsules around a muscle organs body.
TENDONS & APONEUROSES
: connect the connectine tissue fiber form the EPI/PERI/ENDOMYSIA to bones or other structures.
: are cordlike
: are sheet-like
What is the general function of a tendon?
Attach muscles directly to bones.
How is a tendon better suited than muscle tissue to cross over a joint?
Tendons are mostly tough collagenic fibers, so they can cross rough boney projections, which would tear the more delicate muscle tissues.
What is the most abundant fiber in tendons?
How does smooth muscle differ from skeletal muscle in apperance and degree of "control"?
Smooth muscle lacks striations and is not under voluntary control.
In which type of stuctures is smooth muscle commonly found in the body?
Found mainly in the walls of hollow visceral organs such as the stomach, urinary bladder, and respiratory passageways.
How does smooth muscle compare to skeletal muscle in the speed of contraction and ability to maintain contraction and force?
Speed of contraction
Ability to maintain contraction and force
What is the most common arrangement of smooth muscle cells within the wall of an organ?
Usually arranged in two layers ( circular and longitudinal)
Where specifically is cardiac muscle located?
Wall of the heart.
What do "striated" and "involuntary" indicate about the appearance and control of cardiac muscle?
"Striped" and not under direct conscious control.
What is the most common arrangement of cardiac muscle cells within the wall of the heart?
Arranged in spiral or figure 8-shaped bundles around the body of the heart.
Describe the shape of cardiac muscle cells?
Elongated, Blunt ends, and Some branching.
What is an Intercalated disc?
Special junctions between attached cardiac muscle cells that helps coordinate cells activity.
In general, when smooth and cardiac muscle tissues contract, do the make the chamber they are assoicate with larger or smaller?
Smaller ( cardiac makes the heart chamber smaller and thus push the blood out).
Idenitify the four common functions of muscle tissue particularly skeletal muscle.
Producing movement, maintaining posture, stablizing joints, and generates heat.
What is a sarcolemma?
The plasma membrane of the muscluar fiber.
Describe the general appearance of myofibrils?
Rod-like protein organelles running the entire length of fiber, run parallel to one another, densely pacted: hundereds to thousands in each fiber: fill most of the cell, occupying 80% of cell volume.
What are sarcomeres?
The contractile unit of muscle fiber or the distance from z disc to z disc.
How are sarcomeres arranged within a myofibril?
Aligned end-to-end like cars in a train.
Define Actin Filaments?
Thin, composed of protien actin, have binding cites for myosin attachment.
Define Myosin Filaments?
Thick, composed of protien myosin, have sideways projections called heads that connect with action during muscle contractions.