bones + muscles Flashcards
what are the functions of the skeletal system?
support
protection
movement
electrolyte balance
acid-base balance
blood formation
what are the types of bone cells?
osteogenic cells: stem cells that make other types of bone cells except osteoclasts
osteoblasts: bone forming cells (osteogenesis)
osteocytes: former osteoblasts trapped in the matrix of bone and live in lacunae joined by channels called canaliculi
osteoclasts: break down cells
how does bone elongation occur and when
occurs by epiphysial plate occurs until around 19-21 when epiphyseal plate closes.
what is appositional growth?
widening and thickening, this is the deposition of new tissue on surface and continues throughout life.
what is wolffs law?
our bones become thicker and stronger over time to resist forces placed upon them and thinner and weaker if there are no forces to act against, ie when you play tennis bones get wider.
what is the behaviour of skeletal muscle fibers
excitation
excitation-contraction coupling
contraction
relaxation
muscle twitch phases
latent period
contraction phase
relaxation phase
what is an isometric contraction
this is tension produced by the muscle by going to lift something but not actually lifting it, static change but no joint angle change.
what is an isotonic contraction
this is the change in length but no change in change in tension, dynamic strength
what is a concentric contraction
shortening and decreasing joint angles
what is eccentric contraction
this is the lengthening of joint angle.
During muscle contraction which bands of the sarcomere are shortened?
the I and H bands are shortened.
Which part of the sarcomere is the myosin myofilaments not attached to?
the Z disc
what is not transported back into the sarcoplasmic reticulum during contraction?
Ca+
