Muscles and Skin Flashcards
What are controls voluntary movement?
the somatic nervous system
Myocytes
muscle cells
Myofilaments
composed of actin and myosin
Sacromere
repeating unit of myosin and actin
What makes muscles look striated?
sacromeres
Which muscles have sacromeres?
skeletal and cardiac muscles
Two types of skeletal muscles
1) red slow-twitch
2) white fast-twitch
White fast-twitch fibers
type of skeletal muscle that has less mitochondria
relies on glycolysis for quick energy metabolism
Red slow-twitch fibers
type of skeletal muscle that has more mitochondria
relies on oxidative phosphorylation for endurance
Which type of cells have many nuclei?
skeletal muscles
Z-line
exists at the end of sarcomeres
M-line
middle of the sarcomere
H-zone
contains only thick filament (myosin)
I-band
contains only thin filament (actin)
A-band
entire thick filament
Cross bridge cycle 3 steps
1) ATP binds myosin head which triggers conformational change to release myosin
2) ATP is hydrolyzed to ADP to move myosin
3) Myosin rebinds actin at a further position and contracts
What is myosin normally blocked by?
trypomyosin
What is needed for contraction to occur?
Ca2+ and ATP
How does Ca2+ allow the contraction to occur?
Ca2+ binds to troponin to release myosin from trypomysosin and allow it to bid actin
How do neurons control muscle contraction?
neurons release acetylcholine
acetylcholine opens Na+ channels to depolarize cell
action potential causes Ca2+ to be released
Rigor mortis
occurs when myosin head can’t release actin
What could be a consequence of inhibited acetylesterases?
acetylcholine would not be degraded
this would cause constant muscle contraction
Intergumentary system
another name for skin
Where are mechanoreceptors found?
in the dermis and epidermis
Where are adipose cells found?
in the hypodermis
Vasodilation
helps with cooling
