Skeletal and Muscular System Flashcards
(27 cards)
Main functions of skeleton?
support, protection and movement
Main types of skeleton?
- hydrostatic skeletons
- exoskeletons
- endoskeletons
hydrostatic skeleton?
- consist of fluid held under pressure in a closed body compartment
- flatworms, cnidarians, nematodes and annelids
- to change the shape of fluid-filled compartments
exoskeleton?
- hard encasement
- deposited on the surface of animal
- found in molluscs and arthropods
endoskeleton?
-hard supporting elements
-bones
-found in sponges, echinoderms and chordates
mammalian skeleton is built more than 200 bones
Function of muscles and tendons?
help to support large land vertebrates
skeletal muscles are attached to the skeleton in?
antagonistic pairs
skeletal muscle consists of?
bundle of long fibers
muscle fiber?
bundle of smaller myofibrils arranged longitudinally
myofibrils are composed of?
- thin filaments (2 strands of actin and 1 strand of regulatory protein)
- thick filaments (staggered arrays of myosin molecules)
skeletal muscle is also known as and why?
- striated muscle
- the regular arrangement of the myofilaments creates a pattern of light and dark bands
in vertebrate skeletal muscle, each repeating unit is called?
- sarcomere
- bordered by Z lines
- thick filaments attached at the M lines centered in the sarcomere
- area contain myofilaments
- I band, A band and H zone
- muscle at rest
- partially overlap (thick and thin filaments)
sliding-filament model of muscle contraction?
- the filaments slide past each other longitudinally
- producing more overlap between thin and thick filaments
result of sliding?
- I band and H zone shrink
a. relaxed muscle fiber - I bands and H zone wide
b. contracting muscle fiber - thick and thin slide past each other, reducing the width of the I bands and H zone and shortening sarcomere
c. fully contracted muscle fiber. - sarcomere is shorter still
- thin filament overlap, eliminating H zone
- I bands disappear as the end of thick filament contract the Z lines
skeletal muscle fiber contracts?
when stimulated by a motor neuron
infoldings of the plasma membrane called?
transverse tubules
action potential along the T tubules?
causes the sarcoplasmic reticulum to release Ca2+
Why the Ca2+ binds to the troponin-tropomyosin complex on the thick filament?
exposing the myosin-binding sites and allowing the cross-bridge cycle to proceed
how many muscles are in the human body?
600 / 640
how many bones are in a adult human body?
206
Which system is responsible for creating red blood cells?
skeletal
A socket type of joint is one that can move to multiple directions. Which one below is a socket type of joint?
shoulder
A hinge type of joint is one that moves back and forth only. Which one below is an example of hinge type of joint?
elbow
What is the difference between ligament and tendon?
- ligament connects bone to bone
- tendon connects muscle to bone
