Skeletal muscle tissue Chapter 11 Flashcards
What is:
-Attached to the bones
-Striated
-Voluntary
Skeletal muscle
What are the 3 functions of skeletal muscles?
1-Motion
2-Maintenance of posture
3-Heat production
What is:
-Fibrous connective deep to the skin around muscle fibers and other organs and lines body walls
Fascia
Fascia is made up of what type of tissue?
Dense irregular connective tissue
(Extension of fascia)
What:
-Covers entire muscle
Epimysium
(Extension of fascia)
What:
-Covers fascicles which are bundles of muscle fibers
Perimysium
(Extension of fascia)
What:
-Covers and separates muscle fibers
Endomysium
(Extension of fascia)
What is:
-Extension of all 3
-Attaching muscle to the periosteum of bone
Tendon
(Extension of fascia)
What is:
-Flat broad shaped tendon
Aponeurosis
What are made from:
-Muscle cell
-Long cylindrical in shape
Muscle fibers
What is another name for muscle fibers?
Myofibers
(Anatomy of skeletal muscle)
What are made from:
-Plasma membrane
Sarcolemma
(Anatomy of skeletal muscle)
What are made from:
-Cytoplasm
Sarcoplasm
(Anatomy of skeletal muscle)
What are:
-Comparable to smooth endoplasmic reticulum
Sarcoplasmic reticulum
(Anatomy of skeletal muscle)
What are:
-Dilated sacs of sarcoplasmic reticulum
-High concentration of calcium ions
Terminal cisterns
(Anatomy of skeletal muscle)
What are:
-Extensions of the sarcolemma that penetrate the center of the muscle fibers
Transverse tubules (T tubules)
What are:
-Contractile elements of skeletal muscles
Myofibrils
Myofibrils contain smaller structures called _________
Filaments (Myofilaments)
What are the 2 major types of myofibrils
-Thick filaments
-Thin filaments
Myofilaments are arranged in compartments called __________ which run from Z disc to Z disc
Sarcomeres
Put these in order from largest to smallest:
-Myofiber (muscle cell)
-Filaments (Myofilaments)
-Fascicle
-Myofibril
-Muscle
-Muscle
-Fascicle
-Myofiber
-Myofibril
-Filaments
Which filaments are made up of protein molecules called myosin?
Thick filaments
Projecting myosin heads are called _____ ________
Cross bridges
These protein molecules make up what?
-Actin
-Tropomyosin
-Troponin
Thin filaments
Name the three protein molecules that make up thin filaments
-Actin
-Tropomyosin
-Troponin
Each actin molecule has a ________ _____
Binding site
(Components of a Sarcomere)
What are:
-Proteins that separate one sarcomere from the next
Z discs
(Components of a Sarcomere)
What:
-Extend from one end of thick filament to the other
A band
(Components of a Sarcomere)
What are:
-Thin filaments but no thick filaments
I band
(Components of a Sarcomere)
What are:
-Thick filaments but no thin filaments
H zone
(Components of a Sarcomere)
What are:
-Proteins that hold thick filaments together
M line
(Components of a Sarcomere)
What are:
-A protein that connects the Z disc to the M line
Titan
(Components of a Sarcomere)
What are:
-Very elastic and allows the sarcomere to return to its resting length after contraction or stretching of the muscle
Titan
What is:
-The region between a somatic motor neuron and a skeletal muscle fiber
Neuromuscular Junction
(Neuromuscular junction)
What is:
-The area between two neurons or a neuron and a muscle
Synaptic cleft
(Neuromuscular junction)
What is:
-Contain neurotransmitter (Acetylcholine)
Synaptic vesicles
(Neuromuscular junction)
What is the:
-Muscle fiber part of the NMJ
-Portion of sarcolemma
Motor end plate
(Nerve impulse activates muscle action potential)
1. Nerve impulse reaching _______ _____ _____ causing Ca2+ influx which releases acetylcholine (ACh) from synaptic vesicle
Synaptic end bulb
(Nerve impulse activates muscle action potential)
2.ACh molecules bind to receptors on motor end plate. Channels open & allow Na+ to flow into ________ _________.
Muscle membrane
(Nerve impulse activates muscle action potential)
3. Na+ inflow triggers an action potential in muscle. Action potential travels into __ ________.
T Tubule
(Nerve impulse activates muscle action potential)
4. ACh activity broken down by ________________________.
Acetylcholinesterase
(Sliding Filament Mechanism)
1. Muscle fiber action potential ( _________ )
Excitation
(Sliding Filament Mechanism)
2. AP conducted into fiber by __ _______.
T Tubule
(Sliding Filament Mechanism)
3. AP in T tubules cause _________ ________ to become permeable to calcium.
Terminal cisterns
(Sliding Filament Mechanism)
4. Calcium diffuses out of cisterns into _____________.
Sarcoplasm
(Sliding Filament Mechanism)
5. Calcium combines with troponin– tropin changes shape and pulls ___________ off active sites on actin
Tropomyosin
(Sliding Filament Mechanism)
6. ATP broken down into ADP + P and activates (energizes) the ______ _______.
Myosin head
(Sliding Filament Mechanism)
7. Attachment of head of myosin to active site (on actin). This causes release of the _________ _______.
Phosphate group
(Sliding Filament Mechanism)
8. ________ _______ - release of the phosphate group causes head to flex, pulling actin filament towards the center of the ______ ________ (H zone).
-Power stroke
-Thick filaments
(Sliding Filament Mechanism)
9. Once the head ______ it releases ADP.
Flexes
(Sliding Filament Mechanism)
10. ATP binds to ATP binding sites (on myosin) and causes _____ _______ to release.
Cross bridges
(Sliding Filament Mechanism)
11. What step does the process restart at?
Step 6
What process continues over and over, continually moving the thin filaments toward the H zone?
Sliding Filament mechanism
The Sliding Filament Mechanism repeats as long as what 2 things are present?
-Calcium level is high
-ATP is available
What happens when:
-Action potential ceases
-Calcium pumped out of sarcoplasm into the sarcoplasmic reticulum
-Fiber relaxes
Relaxation
What happens when:
-Troponin releases calcium
-Troponin molecule returns to original shape pulling tropomyosin strands over the active sites
Relaxation
What is:
-A state of muscular rigidity that begins 3-4 hours after death
Rigor Mortis
About how long does Rigor Mortis last?
24 hours
(Rigor Mortis)
After death, Ca2+ ions leak out of the SR and allow ______ ______ to bind to actin.
Myosin heads