1. Structure and function of body system Flashcards
Axial and Appendicular skeleton
Axial: skull, column, ribs and sternum
Appendicular: limbs system
Column vertebrae numbers
5 cervical, 12 thoracic, 5 lumbar, 5 sacral, 3-5 coccygeal
Categories of joint
Fibrous -> cartilaginous -> synovial
Synovial are: Uniaxial, biaxial e multiaxial
Layers of muscle tissue
Epimysium contiguous with tendons cover the muscle system.
Perimysium, fasciculi of muscle fibers
Endomysium, single muscle fiber contiguous with sarcolemma.
Motor unit structure
Motor neuron that innervate a group o muscle fibers, linked by the neuromuscular junction
myofibrils
They dominate the sarcoplasma, and are myosin and actin. Their connection is a cross bridge
Strain and sprain
Muscle get strain
Tendon get sprain
Sarcomere structure and size
Length 2.5u
Myosin is surrounded by 6 actine
Actine is surrounded by 3 myosin
Structure: Z [I - A(H) - I] Z
What band do not change length during contraction ?
A band do not change.
Steps for a muscle contraction
- Motor neuron fires an electrical impulse called action potential
- Acetylcholine is released across the NJ
- Calcium stored into the sarcoplasmic reticulum is spread into the sarcomere by T-tubules
- Actine and myosin link and contracts
Actine and Ca+
When Ca+ reach actine, Troponin binds with Calcium ions, and Tropomyosin moves and let the actine active site for the myosin head attach.
In resting phase how the actine a myosin acts ?
There’s a little concentration of Ca+ in the myofibrils and even if actine site is covered, there’s tension between some myosin and actine
Power stroke comes from ?
hydrolysis of ATP into ADP and phosphate and a release of energy.
Twitch and tetanus
Twitch: single brief contraction
Tetanus: merge of twitches in sequences
Classification motor units
Ia slow, IIa fast aerobic, IIx fast anaerobic
Power and strength came from
Increase in firing rates of singles MU and larger recruitment of them
Muscle spindle
Intrafusal or extrafusal fibers the run along the muscle fibers and provide information about the length of the muscle. If danger length occur so the m.spindle create a greater activation of the agonist muscle
Golgi tendon organs
Located as dots in the tendon, if the tension on it increase, they inhibit the motor neuron
Blood path
(from big circulation)
Vena cava - Right atrium - tricuspide valve - right ventricle - pulmonary artery
(get O2 in lungs small circulation)
Pulmonary vein - left atrium - mitral valve - left ventricle (bigger) - Aorta
(to big circulation with O2)
Sinoatrial node SA and Purkinje fibers
pacemaker of heart rhythm of impulse
AV nodes pass the impulse to ventricle and Purkinje fibers conduct to all parts of ventricles.
Waves P Q R S T
P depolarization of atria
QRS depolarization of ventricle
T repolarization of ventricle
Exchange of gases occur in
Alveoli with diffusion
