Ch. 10 Muscle Tissue Flashcards
Anatomy of Skeletal Muscle
Largest to smallest component
Muscle
Fascicle
Muscle fiber
Myofibrils
3 connective tissue layers:
an outer epimysium (wraps a whole muscle):
a middle perimysium (wraps fascicle):
an inner endomysium (wraps an individual fiber):
1/3 connective tissue layers:
outer epimysium wraps around what
an outer epimysium (wraps a whole muscle):
a middle perimysium wraps around what
wraps fascicle
an inner endomysium wraps around what?
muscle fiber
Attachments of muscle to bone
What are cordlike structure of dense regular connective tissue
Tendons
thin, flattened sheet of dense irregular tissue
Aponeurosis
Parts of a muscle cell:
Bundle of Myofilaments
Myofibirils
Parts of a Myofibiril:
Thick filaments
Myosin
Parts of a Myofibiril:
Myosin Filaments are Thin or Thick?
Thick
Parts of a Myofibiril:
Thin Filaments
Actin
Parts of a Myofibiril:
Is Actin Thin or Thick?
Thin
2 Regulatory Proteins of Thin Filament
Tropomyosin
Troponin
internal membrane complex similar to smooth endoplasmic reticulum
Sarcoplasmic Reticulum
blind sacs of sarcoplasmic reticulum
Terminal Cisternae
What serves as reservoirs for calcium ions (Ca2+)
Sarcoplasmic reticulum
Myofilaments are arranged in repeating, functional units called
Sarcomeres
Part of Sacromere:
What are at the ends of Sacromeres
Z Discs
Part of Sacromere:
What do Z Discs do
(At the end of Sacromeres)
(anchors the thin filaments)
Part of Sacromere:
Light-appearing regions that contain only thin filaments
I-bands
(remember L I G H T band)
Part of Sacromere:
Dark-appearing region that contains thick filaments & overlapping thin filaments
A-band (remember D A R K band)
Part of Sacromere:
central portion of A band (only thick filaments)
H zone
Part of Sacromere:
middle of H zone
M line (mid line)
attachment site for thick filaments
Part of Sacromere:
attachment site for thick filaments
M line
Microscopic Anatomy of Skeletal Muscle
allows storage of oxygen used for aerobic ATP production
Myoglobin
motor neuron and all the muscle fibers it innervates and controls.
Motor unit
location where a motor neuron innervates a muscle fiber.
Neuromuscular junction
What houses synaptic vesicles
Synaptic Knob
small sacs filled with neurotransmitter acetylcholine (ACh)
Synaptic vesicles
Synaptic Vesciles are filled with what
neurotransmitter acetylcholine (ACh)
What has Ca2+ pumps in plasma membrane
Synaptic knob
voltage-gated Ca2+ channels are located in the
membrane
Ca2+ flows into cell (down concentration gradient) releasing what
neurotransmitters
What has many ACh receptors
Motor end plate
Locate Synaptic Cleft
What happens just after Na+ channels open,
they close and voltage-gated K+ channels open
When Na+ pushes K+ out what happens?
It repolarizes the cell
Sarcomere: Crossbridge Cycling :
When Ca2+ binds to what , it triggers crossbridge cycling
troponin
Step 1:
When Ca2+ binds to troponin, it triggers what
crossbridge cycling
“Cocked position” Mysosin Head binds to Actin forming “CrossBridge”
troponin and tropomyosin move so what is exposed?
Actin
What moves so Actin is exposed?
troponin and tropomyosin
Crossbridge cycling: has how many steps
4 repeated steps
Step 1:
What happens at Crossbridge formation?
myosin head attached to exposed binding site on actin
+Step 2:
What happens at Power Stroke?
myosin head pulls thin filament toward center of sarcomere
+ADP and Pi release
What releases during Power Stroke (Step 2:)
ADP and Pi release
Step 3:
What happens at the Release of myosin head
ATP binds to myosin head causing its release from actin
Step 3:
What binds to Myosin Head?
What does it do from there?
ATP binds to myosin head causing its** release from actin**
Step 4:
What happens during the Myosin head Reset
ATP split into ADP and Pi by myosin ATPase
provides energy to “cock” (reset) the myosin head
Step 4:
during the Myosin head Reset ATP splits into what
ADP and Pi by myosin ATPase
during the Myosin head Reset ATP, it provides energy to what
to “cock” the myosin head
Criteria for Classification of Muscle Fiber Types
Type of contraction generated (power, speed, duration)
[Fast-twitch fibers are more powerful and have quicker and briefer contractions than what
Slow-twitch fibers
The increase in muscle tension that occurs with an increase in stimulus intensity.
Recruitment (multiple motor unit summation
Increasing the stimulus frequency without increasing the voltage leads to:
wave summation (temporal summation):
wave summation (temporal summation):
wave summation (temporal summation):
relaxation is not completed between twitches
contractile forces add up to produce higher tensions
regions that contain only thin filaments
I-bands
Recruitment changes_____
Voltage
what innervates and controls muscle fibers
Motor Unit
What triggers cross bridge cycling
Ca2+ bins to Troponin
What is located on the membrane?
voltage-gated Ca2+ channels
Step 4:
ATP split into ADP and Pi by what?
myosin ATPase
Type of contraction generated (power, speed, duration) is the criteria for classification of What?
Muscle Fiber Types
ADP and Pi are released during what Step?
Step 2:
myosin head pulls thin filament toward center of sarcomere. ADP and Pi are released (PowerStroke)
Step 4:
What provides energy to reset the Myosin Head ?
ATP is split into ADP and Pi by Myosin ATPhase
What flows into cell (down concentration gradient) releasing Neurotransmitters?
Ca2+
relaxation is not completed between twitches
contractile forces add up to produce higher tensions
wave summation (temporal summation):
