Anatomy & Physiology Chapter 10 Muscle Tissue 1st part

Ch 10 Muscle Tissue
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Terms in this set (...)

Movement, Posture, Support, Guard entrances & exits, Maintain body temperature, Store nutrients
General Functions of Muscles
Epimysium, Perimysium, Fascicles, Endomysium, Tendons, Aponeuroses
Connective Tissue Components of Muscle
Threadlike shape, many mitochondria, several nuclei
Shape and Structure of Muscle Cell
Fusion of many small cells
How is a muscle cell formed?
DNA & RNA for protein synthesis
Why are there so many nuclei?
Sarcolemma
Plasma membrane of muscle fibers
T tubules
Network of tubules & sacs
Extend across sarcoplasm perpendicular to long axis of muscle fiber
Formed by inward extensions of sarcolemma
Ion pumps continually transport Ca2+ inward from sarcoplasm
Allow electrical impulses traveling along sarcolemma to move deeper into cell
Myofibrils
Numerous fine fibers packed close together in sarcoplasm
Each myofibril contains thousands of thick & thin myofilaments
Sarcoplasmic reticulum (SR)
Pumps Ca2+ ions from sarcoplasm & stores ions for later release
Triad
Triplet of tubules
Sandwiched between two sacs of SR
Allows electrical impulse traveling along T tubule to stimulate membranes of adjacent sacs of SR
Sarcomere
Segment of myofibril between two successive Z disks
Each myofibril consists of many sarcomeres
Contractile unit of muscle fibers
A bands
Dark stripes
H zone runs across midsection of A band
I bands
Light stripes
Z disk extends across center of I band
Sarcoplasm
Muscle Cytoplasm
Sarcolemma
Muscle Plasma Membrane
Sarcoplasmic Reticulum
SR
Sarcoplasmic Reticulum
Temorarily Stores Calcium
Piece of sarcolemma that indents
T Tubules
Myofibrils
Made up of thousands of thick myofilaments. Packed closely together.
Myosin
Thick filaments are made up of only
Z line
Thin filaments are anchored by
A Band
Thick filaments a called
I Band
Thin Filaments are called
H line
Thick filaments are anchored by
Actin, Tropomyosin, Troponin
Thin Filaments are made up of
Actin
Globular protein that Forms two fibrous strands twisted around each other
Tropomyosin
Blocks active sites on actin molecules
Troponin
Holds tropomyosin molecules in place
Myosine
Makes up almost all thick filaments, Heads chemically attracted to actin molecules, Heads aka cross bridges when attached to actin.
I shortens, A stays the same length
How are the bands effected when a muscle contracts?
Nueral Control, Calcium Release, Thick Thin filament interaction
What are the 3 steps of muscle contraction?
IMPORTANT
Make cards on process of muscle contractions
Troponin changes shape
When calcium binds to troponin......
ATP
The energy source for muscle contraction is
Relaxation of Muscles
Immediately after Ca2+ is released, SR begins actively pumping it back into sacs. Ca2+ is removed from troponin molecules, thereby shutting down contraction
Small motor control
Less fibers in a unit, fine muscle control, precise movement
Large motor control
More fibers in a unit, fine muscle control, more powerful contaction
Muscle Tone
Tonic contraction. Continual, partial contraction of muscle. Small number of muscle fibers within muscle contract & produce tightness, or muscle tone. Muscles with less tone than normal are flaccid. Muscles with more tone than normal are spastic. Muscle tone is maintained by negative feedback mechanisms.
Isotonic contraction
Tension within a muscle remains same as length of muscle changes. All energy of contraction is used to pull on thin myofilaments & thereby change length of fiber's sarcomeres. Most body movements occur as result of both types of contractions. Two Types are Concentric & Eccentric.
Concentric
Muscle shortens as it contracts. Type of isotonic contraction.
Eccentric
Muscle lengthens while contracting
Concentric & Eccentric
What are the two types of Isotonic Contractions?
ATP
Energy source. Binds to myosin head. Transfers energy to perform work of pulling thin filament during contraction. Continually resynthesized from breakdown of creatine phosphate. Catabolism by muscle fibers requires glucose & O2. At rest, excess O2 in sarcoplasm is bound to myoglobin.
Aerobic respiration
Energy source. Occurs when adequate O2 is available
Slower than anaerobic respiration
Supplies energy for long term
Anaerobic respiration
Energy source. Very rapid. Provides energy during first minutes of maximal exercise. Low levels of O2.
Formation of lactic acid
Energy source. Occurs in Anaerobic respiration. Requires O2 to convert back to glucose. Produces "oxygen debt," or excess post-exercise O2 consumption.
Skeletal muscle contraction
What produces heat & can be used to help maintain set point body temperature?