L6

Question 1

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

Answer 1

long parallel cells (fibres), 30 - 100 μm

Question 2

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.

Answer 2

10-20 μm, 50-100 μm

Question 3

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.

Answer 3

2-10, 100-400

Question 4

Activation of Muscle

  Skeletal muscles are activated by ...

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

Answer 4

action potentials in the motor nerves

–neurogenic contractions

action potentials in autonomic nerves

–myogenic contractions

Question 5

Przypomnienie: Skeletal muscle innervation

Answer 5

• 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.

Question 6

…. 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

Answer 6

Troponin

Question 7

Opisz Type I and Type II skeletal muscle cells

Answer 7

Type I Slow Oxidative

Type II A Fast Oxidative II B Fast Glycolytic

Question 8

The Power of Muscles

Force =

Work =

Answer 8

mass x acceleration

force x distance moved by load

Question 9

Power = ….

jednostki force, work and power

Answer 9

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)

Question 10

Opisz co się dzieje z książką gdy:

Isotonic Concentric

Isotonic Eccentric

Isometric

Answer 10

– książka w górę

• książka w dół

– brak ruchu

Question 11

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

Answer 11

• 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