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Flashcards in L6 Deck (11):

Skeletal muscle is made up of ...., .... in diameter, and vary from mm to ~10cm. Myofibrils (roughly 1 μm diameter).

long parallel cells (fibres), 30 - 100 μm


Cardiac muscle cells are .... in diameter, ...  in length, connected end to end at intercalated discs for mechanical and electrical continuity, at desmosomes (fascia adherens) and gap junctions, respectively; myocardium, functional syncytium.

10-20 μm, 50-100 μm


Smooth muscle cells are about .... μm wide and .... μm long. They are joined together both mechanically (at intermediate junctions) and electrically (at gap junctions), to form functional units in bundles or sheets.

2-10, 100-400 


Activation of Muscle

      Skeletal muscles are activated by ...

      Cardiac and most smooth muscle have an intrinsic rhythm that is modulated by ....

action potentials in the motor nerves

–neurogenic contractions



action potentials in autonomic nerves

–myogenic contractions 


Przypomnienie: Skeletal muscle innervation

•Skeletal muscles are supplied by nerve fibres that are myelinated and have their origin in the CNS.

•Such nerves are called motor nerves.

•When a motor nerve fibre enters a muscle, it branches so that one motor axon makes synaptic contact with a number of muscle fibres.

• The motor neuron, its axon and all the muscle fibres supplied by the axon and its branches form a motor unit. 


.... holds tropomyosin in position to block myosin-binding sites on actin. 

However, Ca2+ binds to ...., which changes the shape of the troponin-tropomyosin complex and uncovers them, causing contraction because myosin binds to actin




Opisz Type I and Type II skeletal muscle cells

Type I Slow Oxidative

Type II A Fast Oxidative II B Fast Glycolytic


The Power of Muscles

Force = 


Work = 

mass x acceleration


force x distance moved by load 


Power = ....

jednostki force, work and power

 work ÷ time = (force x distance) / time = force x velocity


Force= 1 Kg x 1m s-1 = 1 Newton (1 N)

Work = (1 Kg x 1m s-1 ) x 1 m = 1 Newton Metre (1 N.m) or Joule (J)

Power = (1 Kg x 1m s-1 x 1 m) / time = Joule / second ( J s-1 ) or Watts (W)


Opisz co się dzieje z książką gdy:

Isotonic Concentric 

Isotonic Eccentric



– książka w górę

 - książka w dół

 – brak ruchu



The force developed by a muscle depends on (5):

•The number of active motor units

•The cross-sectional area of the muscle

•The frequency of stimulation: – summation of contractions

•The rate of shortening

•The initial length of the muscle