Chapter 12 Flashcards
(56 cards)
What are the three muscle types?
Skeletal muscle , cardiac muscle, smooth muscle
Where is cardiac muscle found
It is only found in the heart
What are most skeletal muscles attached to?
The bones of the skeleton by tendons made of collagen.
Where is smooth muscle located
The primary muscle of the stomach, urinary bladder, and blood vessels
What are skeletal muscles used for?
To move the skeleton
What is smooth muscle used for?
To influence the movement of material into, out of, and within the body.
What does cardiac muscle do?
Moves blood through the circulatory system.
What is skeletal muscle made out of?
Muscle cells that are called Muscle fibers. (Largest cells in body)
Each muscle fiber is a long cylindrical cell with up to several hundred nuclei near the surface of the fiber.
Muscle fiber
A collection of muscle cells
Satellite cells
Committed stem cells that lie just outside the muscle fiber membrane. They become active and differentiate into muscle when needed for muscle growth and repair.
Fascicles
Each muscle fiber is sheathed in connective tissue, with groups of adjacent muscle fibers bundled together into these units called fascicles
Sheath
A structure of living tissue which closely envelops another
Tendon
Made of collagen, attach bones to muscle
Sarcolemma structure and uses
The cell membrane of a muscle fiber, it acts as a barrier between the extra cellular and intracellular compartments, it defines each muscle fiber from its surroundings
Sarcoplasmic reticulum (SR) structure and uses
A form of modified endoplasmic reticulum that wraps around each myofibril like a piece of lace. It consists of longitudinal tubules with enlarged end regions.
The main function is to store calcium ions
Terminal cisternae uses and structure
The enlarged end regions of the longitudinal tubules of the sarcoplasmic reticulum.
Ensures rapid calcium delivery
Myofibril
The main intracellular structures in striated muscles
They are highly organized bundles of contractile and elastic proteins that carry out work of contraction
Sarcomere uses and structure
A structural unit of a myofibril in striated muscle, consisting of a dark band and a light band
Each sarcomere is composed of two main protein structures call actin and myosin which are the active structures responsible for muscular contraction.
Transverse tubule (t-tubule) structure and uses
Extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscles
Allow close interaction between the sarcoplasmic reticulum and sarcolemma
Components of a sarcomere
- Z disks
- I bands
- A band
- H zone
- M line
What does the Z disks do
One sarcomere has 2 Z disks. Zigzag protein structures that serve as the attachment site for thin filaments.
What do I bands do
These are the light color bands of the sarcomere , they represent a region occupied only by thin filaments. A Z disks run through the middle of every I band (each I band belongs to a different sarcomere)
What does the A band do
Dark colored sarcomere band, encompasses the entire length of a thick filament. The center of the A band is occupied by thick filaments only.
What does the H zone do
Central region of the A band, lighter than the outer edges of the A band because the H zone is occupied by thick filaments only.
