Transcript Energy for Muscle Contraction

Energy for Muscle Contraction
Direct Phosphorylation
Aerobic Respiration
Anaerobic Glycolysis
Vocabulary
• Aponeurosis: A sheetlike fibrous
membrane that binds muscles together or
as a means of connecting muscle to bone.
• Motor Unit: A single motor neuron and all
the muscle fibers it stimulates.
• Ligament: A sheet or band of tough,
fibrous tissue connecting bones or
cartilages at a joint
Vocabulary
• Epimyusium: The external sheath of
connective tissue surrounding a muscle.
(outermost)
• Perimysium: The fibrous sheath
enveloping each of the primary bundles of
skeletal muscle fibers. (Middle)
• Endomysium: The connective tissue layer
surrounding an individual skeletal muscle
fiber. (Innermost)
Direct Phosphorylation
• Uses Creatine
Phosphate
– Found only in muscle
– Regenerates ATP
from ADP
– CP exhausted in 20
seconds
– No Oxygen Used
Aerobic Respiration
• Generates ATP in
mitochondria
• Uses Oxygen
• Oxidative
Phosphorylation
• Glucose is broken
down to CO2 and H2O
– 36 ATP per 1 glucose
– Slow process
– Lasts for hours
Anaerobic Respiration
• Glycolysis uses no
oxygen
• Occurs in cytosol
• Broken down to pyruvic
acid which is converted to
lactic acid when oxygen
cannot keep up to
demand
• 2 ATP per glucose
• 30-60 seconds
Energy Sources
• First: Glucose
• Second: Pyruvic
Acid
• Third: Fatty Acids
stored in adipose
tissue
• Fourth: Amino Acids
from protein
catabolism
Muscle Fatigue
• Muscle cannot
contract even
when stimulated
• Weaker and
weaker until it
stops
• Results from
Oxygen debt
• Build up of lactic
acid and lack of
creatine
phosphate and
ATP reserves
Oxygen Debt
• Prolonged
workouts
• Oxygen uptake
can no longer
keep up
• Results in rapid or
deep breathing
• Muscle may quit
entirely
Hitting the Wall
•
•
•
•
Bonk
Glycogen depletion
Extreme fatigue
Remedied by
carbohydrates
Movements
• Flexion
• Extension
• Hyperextension
Movements
• Abduction
• Adduction
• Circumduction
Movement
• Plantar Flexion
• Dorsiflexion
Movement
• Rotation
• Medial Rotation
• Lateral Rotation
Movement
• Supination
• Pronation
Movement
• Inversion
• Eversion
Review Sarcomere
More Vocabulary:
• Sarcolemma: Plasma membrane of a
muscle cell
• Myofibril: Long organelles that fill the cell
and are composed of myofilaments
• Myofilaments: threadlike protein fibers
– Thick filaments = Myosin
– Thin Filaments = Actin
Muscle Characteristics
• Skeletal: Multinucleate, Striated, Long
Thin Cells. Attached to bones. Voluntary
• Cardiac: Branched, Uninucleate,
Striated, Intercalated discs. Walls of
Heart. Involuntary
• Smooth: Fusiform (tapered),
Uninucleate, No striations. Involuntary.
Vocabulary
• A Bands = Dark bands of a myofibril
• I Bands = Light bands of a myofibril
• Z Disc or Z Band= Interruption in the
center of the I Band
• M Line: Holds thick filaments together and
can be seen in the center of the H zone
• H Zone: Light central area of sarcomere
that lacks actin (also bare zone) this
disappears during contraction when fibers
overlap
Muscle Contraction Review
1. Motor neuron is
stimulated and
the action
potential
travels along
the neuron.
Muscle Contraction
2. Acetylcholine is
released from
the neuron end
plate into the
neuromuscular
junction
Muscle Contraction
3.Acetylcholine diffuses across the neuromuscular
junction gap
Muscle Contraction
4. The muscle
fiber
membrane is
stimulated,
impulse travels
through
transverse
tubules to
sarcoplasmic
reticulum
Muscle Contraction
5. Sarcoplaspic
reticulum
releases
Ca+2 into the
sarcoplasma
Muscle Contraction
6. Calcium binds
to troponin on
the actin (thin)
filaments
allowing
myosin (thick)
filaments to
form crossbridges
Muscle Contraction
7&8 Power
Stroke occurs
and repeats as
long as calcium
is present and
the muscle
shortens
Muscle Contraction
9. Motor neuron
stimulation
stops.
Cholinesterase
causes the
breakdown of
acetylcholine
Muscle Contraction
10. Calcium ions
are pumped out
into the
sarcoplasmic
reticulum using
active transport
Muscle Contraction
11& 12 Linkages
between actin
and myosin are
released. The
muscle relaxes to
its pre-stimulated
length
Quiz Tuesday – Muscle Physiology