Skeletal muscle
Voluntary movements
Striated
Cardiac muscle
Involuntary beating of the heart - myogenic
Cells are electrically couples
Striated
Resistant to tearing and intense pressure
Action potential spreads fast
Myofibrils
Highly ordered assemblages of myosin and actin filaments
In muscle fibers
Actin
Thin filaments
Actin monomers + tropomyosin + troponin
Myosin
Thick filaments
Motor unit
One motor neuron and all the muscle fibers it synapses with
Muscle membrane
Sarcolemma
Muscle cytoplasm
Sarcoplasm
Troponin
Binds to actin, tropomyosin, and calcium
Muscle endoplasmic reticulum
Sarcoplasmic reticulum
Neuromuscular junction
Synapse of neuron to muscle
Tropomyosin
Covers myosin binding points on the actin filament
Hydrolysis of ATP
ATP + H2O –> ADP +Phosphate + Energy
Glycolytic system
Metabolism of glucose through enzymes
Available through the cytoplasm of the cell
Fast reaction
Harvesting of carbs
Power stroke
When the phosphate group falls off the myosin head, causing a large change in myosin conformation
Allows the filaments to slide past each other
Slow-twitch muscle fibers
Have a lot of mitochondria Use the oxidative system Contain myoglobin and blood vessels Low maximum tension but high resistance to fatigue Ex. hamstrings
Fast-twitch muscle fibers
Use the glycolytic system
High maximum tension but low resistance to fatigue
Good for short-term work
Ex. biceps
Noreponephrine
Accelerates heart rate
Inhibits smooth muscles
Released by the sympathetic nervous system
Neurotransmitter
Smooth muscle
Involuntary movement of internal organs Cells are arranged in sheets Long, spindle shaped Provide contractile force for most internal organs Stretch causes action potential
Immediate system
Uses pre-formed ATP and creatine phosphate
Available immediately
Osteoblasts
Fresh, new bone cells
Follows the osteoclasts and lays down the new bone material
Build up new bone
Osteocytes
Thick extracellular matrix layer
Osteoclasts
Dig the bone
Release calcium and minerals from the bone
Break down old bone
Oxidative system
Slow metabolism
Depends on mitochondria and oxygen
Takes time
The complete burning system of the muscle
Acetylcholine
Inhibits heart rate
Stimulates smooth muscle
Released by the parasympathetic nervous system
Hydrostatic skeleton
Liquid inside the body works with the muscles to provide movement
Exoskeleton
Skeleton is outside the body
When the body grows, the animal must molt, leaving it vulnerable
Provides good protection
Endoskeleton
Provides support
Allows the rest of the body to grow together
Osteoporosis
Loss of bone density
Joints
Where two or more bones come together
Ligaments
Hold bones together at joints
Tendons
Join muscles to bone
Flexor
The muscle that bends the joint
Extensor
The muscle that straightens the joint
Gap junctions
Connect the cardiac cells together
Allow the free flow of ions
Striated
Stripes
Skeletal muscles
In the sarcomeres
Sarcomere
Smallest unit of contraction
Found in skeletal muscles
Z line
Beginning to end of sarcomere
A band
Length of thick filament + overlap
H zone
Length of thick filament without overlap
I band
Thin filament only
M band
“midline”
Lind down the center
DHP receptor
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Ryanodine receptor
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