Lecture 1 - Lucas Flashcards
what are 4 ways that the muscle is used?
movement, energy source, heart circulation, digestive system, sight, heat
4 types of muscle overall
striated
-skeletal (voluntary)
-cardiac (involuntary)
smooth
- single unit ( gut muscles)
- multi unit (iris of the eyes)
2 types of striated muscle
skeletal (voluntary movement, straight thick) and cardiac (involuntary movement, curvy thick)
2 types of smooth muscle
Single-unit (e.g., gut muscles)
Multi-unit (e.g., iris of the eye)
muscle is thin and wavy for both
for slow, sustained contractions
muscle fibers are also called 2 other names
myocyte and muscle cell
muscle cells are [blank] due to fusion of [blank] cells during development.
multinucleated, precursor
muscle cells are compose of protein strands called
myofibrils
Myofibrils are divided into smaller units called [blank]
The arrangement of thick [blank] and thin [blank] filaments creates the striated appearance characteristic of skeletal muscle.
sacromeres, myosin, actin
Contractile Unit of Muscle
Components of Sacromere :
Name the bands and lines (6)
A band, I band, M line, Z line, titin, h zone
Sarcomere Structure (Contractile Unit of Muscle)
Components:
A-band: [blank]
I-band: [blank]
M-line: [blank]
Z-line: [blank]
titin: [blank]
h zone: [blank]
A band: Region of overlap between thick and thin filaments.
I band: area of thin filament only
M-line: A vertical line in the center of the A-band (center of sacromere) that links thick myosin filaments together.
z line (disc): anchor the barbed ends of actin filaments at the ends of the sarcomere (zig zag line in I band).
Titin: A connecting filament that links myosin filaments to actin filaments
H-zone: contains only thick filaments, lighter middle portion in thick filament
3D Organization of sacromeres
2 [blank] filaments surround 1 [blank] filament in vertebrate muscles.
thin, thick
thick filaments are made of myosin [blank] and myosin [blank] chains
myosin heavy and myosin light chains
Myosin heavy chains come in [blank]
pairs
head of thick filaments is made of 2 things
ATPase and actin binding site
right below the head of the thick filament is an …
essential myosin light chain
there is a regulatory myosing —— chain at the neck of the thick filament
light
Thick Filaments
Composed of myosin
Heads:
Arranged ——.
Interact with ——- for contraction.
Tails:
Form the filament’s ——
Bare Zone: Central region without myosin heads, also known as —–
Functional analogy: Brush bar of a vacuum cleaner.
heads are arranged spirally, shaped like a brush bar of a vacuum cleaner.
heads interact with actin
tails form the filament’s body and sticks out
H zone
Thin Filaments
Composed of:
—- actin and —- actin (polymer and monomer)
Componsed of Accessory proteins:
2 accesory proteins…
In f actin, myosin binding site on actin is always —— but in the thin filament (f actin + accesory protein), myosin binding site is regulated by ——-
f actin, a polymer of g actin (monomer)
composed of tropomyosin and troponin
available, but regulated by accessory proteins
Hierarchical Structure of Skeletal Muscle
Muscle fibers
Myofibrils
Sacromeres
Muscle
Fascicles
order them
Sacromeres - Myofibrils → Muscle fibers → Fascicles → Muscle.
What is wrapped in connective tissue sheaths for elasticity?
Attachments:
Muscle fibers connect to —–, which anchor to ——
fascicle and muscle
tendons, anchor to bones
connective tissue sheaths bring elasticity, protection, and help transmit force needed for movement
