Lecture 6 Test 3 Flashcards
Largest contributor to body weight and volume in non-obese people.
Skeletal muscle
What does skeletal muscle regulate?
Body temperature, glycogen, ions
What is glycogen (energy)?
Large chain of sugars (starch) broken down to glucose
40% of body mass; large container?
Skeletal muscles
Targets or effectors of the CNS
Skeletal muscles
Where is glycogen stored?
Liver and muscles
Bone-bone connection are held by
Ligaments
Muscle-bone connection
Tendons
Are all tendons muscle-bone connections?
Vast majority yes but some are intermediary (muscle-muscle)
Tendon bridge?
muscle-muscle
Group of (200) myofibril
Muscle cell/fiber
Group of muscle fibers/cells
Fasciculous; (Plural) Fasciculli
Group of fasciculli
Muscle
Group of muscle
Skeletal muscle
Contractile proteins
Actin/Myosin
Cylinders that contain actin/myosin
Myofibril
Stronger the muscle cell =
More myofibrils
What control precise control of muscle movements?
Weaker muscle cells
Functional unit of myofibrils; where thin and thick filaments can overlap
Sarcomere
Collection of muscle fibers and a motor neuron
Motor unit
How many muscle cells can 1 motor neuron control?
1 or more
small motor unit is useful for
-easy to excite
-Smaller fine motor control, tasks
How is the large motor unit activated?
-Usually starts off with small motor unit and if we need more strength, larger motor unit is activated
-Harder to excite more stimuli req
2 types of skeletal muscles
Type 1: Longer contractions
- (red) slow contractions, lots of myoglobin (iron containing), lots of mitochondria
Type 2: Fast twitch
- (white) fast contractions, less mitochondria, less myoglobin
Ex. of type 1 muscle: Fast twitch
Chicken breast flying from low hanging tree
Ex Type 2 muscle: Longer contractions
Geese flying 30,000 ft
goose/duck breast
Dark meat
Chicken breast
White meat
AKA Soleus muscle
Calf muscle.
-Able to sustain a force for extended period of time per AP. Takes awhile to get going but contained weight bearing for a long period
Ocular muscles in regards to action potentials
Fast/short reaction time per AP. less myoglobin than calf muscle
Gastronecmius
Muscle next to soleus (calf) faster acting than soleus, in between ocular and soleus speed of contraction
Action potentials for ocular, gastrocnemius and soleus all look the same.
They just have different reaction contraction time response
T/F: All muscles in the body are a mix of the 2 types.
True
Muscle Cell wall
Sarcolemna
Fluids in sarcolemma
Sarcoplasm
Source of muscle ca++
Sarcoplasmic reticulum
Allows AP to be delivered deep into muscle fibers (myofibrils)
Transverse tubules
Other names for cardiac and skeletal muscle
Striated muscles
striation - alternating patterns within the muscle
Thick filaments
Myosin
Thin filament
Actin
End structure (sarcomere) where thin filaments (actin) are anchored
Z disk
Thin filaments section
I band
Area where actin/myosin overlap
A band
Area where it’s only myosin filaments
H band/zone
Stretchy connective tissue that anchors actin/myosin in skeletal muscle
Titin
*Look at pictures of mitochondria in the muscles under a microscope
Why are skeletal muscle multi nucleated?
Protein production, instructions
Motor neuron is really long with ATP on the end of the axon. Need a transport system to receive proteins from the nucleus on the other end of the neuron via
“train tracks”
1 Myosin “thick filament” consists of
200 Myosin molecules that are wrapped and twisted by their tails to make 1 filament.
Each myosin molecule has ___
6 chains total
2 (heavy chains): larger wrapped/spiraled around each other
4 (light chains): smaller
2 outer (essential) at the head atpase activity.
2 inner at the head - regulatory determine the heads activity level
do we have phosphorylations in skeletal muscles?
No
What is “F actin”?
Thin filaments; Actin molecules that Myosin head binds to
Actin (thin filaments)
2 protein strands
F actin - regulatory, and site for binding with myosin
Tropomyosin - functions as a shield and doesn’t let the myosin heads bind
Troponin complex
Regulatory - (3) proteins.
Troponin-I > grabs to actin
Troponin-T > grabs to tropomyosin
Troponin-C > 4 binding sites for calcium. When bound, twists T&I to allow myosin to bind to F actin and contract.
cross bridge cycling process
Is the process when the myosin head binds and detaches to the actin filaments
Steps for cross-bridge cycling
Ca++ binds to troponin-C > Troponin-C twists T&I > Myosin binds to actin > Myosin head dephosphorylate > Myosin head is full of energy and pulls on actin > shorten the Sarcomere closer together > releases GDP > Myosin head stuck on Actin > Myosin head contact with ATP and release from Actin > ATP metabolized (ADP + P) > relaxed state
What happens if there’s no ATP in the cross-bridge process?
Myosin head will stay stuck on the actin with no force = stiff (rigor mortis).
1 neuron can innervate how many muscle cells?
1 or more muscle cells
If a sarcomere is over stretched, can you produce force?
No,
ex. over time if the heart muscles get stretched over and over, walls get thinner and force of contraction decrease.
Optimal stretch and contraction.
A muscle that is stretched enough before the point of being overstretched can cause a strong contraction.
C based on the diagram is best per Dr. Schmidt
If a muscle is under stretched, can you generate any force?
No, there’s no room to contract (shorten)
What can you do to make under stretched muscles perform better?
Stretch them out.
When a ripped tendon (achilles) is surgically repaired, can it perform back to normal?
No, because when it’s repaired, they are overlapped and connected. Not the same as before. It is now increased stretch and decreased mobility
It will function but not optimally
Is the heart under stretched, overstretched or optimal stretched?
Understretched, in a normal person if we have more preload, it’ll stretch more and cause a more purposeful contraction. (Starlings law)
explain Active tension
If the muscle is under stretched and cause an AP, result would be minimal contraction.
If overstretched and produce an AP = no contraction.
If optimally stretched and produce an AP = strong contraction
passive tension
outside force to achieve a stretch
active tension
Force that’s produced in the contracting muscle as the result of the AP
Total tension
Combination of passive tension - active tension.
Achilles tendon tears repair process
fastens to the gastrocnemius and soleus muscle to the heel bone (calcareous bone)
