BL Muscles Flashcards
Outline the types of muscles
non striated muscle - smooth muscle
striated muscle - skeletal + cardiac muscle
What is myalagia?
Muscle pain
What is myasthenia?
Muscle weakenss
What is myoclonus?
Sudden spasm of muscles
What muscle types are striated?
What are the main features?
Skeletal muscle
Cardiac muscle
Myoglobin present
Striped
What is myoglobin?
Red protein containing haem
Carries and stores oxygen in striated muscle cells
What is detected in the blood when skeletal muscle dies?
Myoglobin
What can high levels of myoglobin in the blood cause?
What can be used to detect this?
Renal damage»_space; tea coloured urine
Define each of these words:
- sarcolemma
- sacroplasm
- sarcosome
- sacromere
- sacroplasmic reticulum
- sarcolemma - outer membrane of a muscle cell
- sacroplasm - cytoplasm of a muscle cell
- sarcosome - mitochondrion
- sacromere - contraction unit of striated muscle
- sacroplasmic reticulum - smooth ER of muscle cell
Explain the relationship between haemoglobin and myoglobin
Haemoglobin gives up oxygen to myoglobin, especially when pH is lowered
Active muscles produced CO2 or lactic acid»_space; results in acidic conditions
What is a muscle fibre?
A striated muscle cell
Describe the skeletal muscle structure
- Actin and myosin within sarcomeres
- Many sarcomeres makes up a myofibril
- Many myofibrils make up a muscle fibre
- Muscles fibres are packaged into fascicles
- Endomysium between individual muscle fibres
- Perimysium wraps around a fascicle
- Epimysium wraps around many fascicles
What is created at the origin and insertion tendon point of skeletal muscle?
Tension at origin tendon point
Movement at insertion tendon point
Describe a sarcomere under a microscope
A band - myosin + actin - dark
H zone - myosin only
I band - actin only - light
Z lines at either end of the sacromere
Dark M lines in middle of sarcomere
Dark Z line | light I band | dark A band | light I band | Dark Z line
Causes of muscle atrophy
Muscle inactivity
Malnutrition
Cancer
Neurogenic
What are the types of muscle contraction speeds?
Slow - red
Fast - white
Intermediate - white
Compare slow and fast twitch fibres in relation to:
- capillary supply
- aerobic or anaerobic
- myoglobin levels
- mitochondria
- cytochromes
- colour
- fatigue
- function
Slow twitch:
- rich blood supply
- aerobic
- high myoglobin levels
- many mitochondria
- many cytochromes
- red
- fatigue resistance
- endurance type activities
Fast twitch:
- poor capillary supply
- anaerobic
- low myoglobin levels
- few mitochondria
- few cytochromes
- white/pale
- rapidly fatigues
- strength
Describe the structure of actin filament
- Forms a helix
- Tropomyosin molecules coil around > reinforcement
- Troponin complex attached to tropomyosin molecule
- Made of actin fibres + actin globules
What does continued muscle contraction depend upon?
Ca2+ ions
Amounts of ATP
Describe the structure of cardiac muscle fibres
Striated
Centrally positioned nuclei
Intercalated discs
Branching
Explain and describe the use of troponin in enzyme assay
Used a marker for cardiac ischaemia
Released from ischaemic cardiac muscles
Indicative of cardiac muscle damage
What can be detected in the blood after cardiac muscle damage?
Troponin
Outline the morphology, connections, control and power of skeletal muscles
-
Morphology - long parallel cylinders
- multiple peripheral nuclei
- striations -
Connections - fascicle bundles
- tendonds - Control - somatic + voluntary
- Power - rapid + forceful
Outline the morphology, connections, control and power of smooth muscles
-
Morphology - spindle shaped tapering ends
- single central nuclei
- no striations -
Connections - gap junctions
- connective tissue - Control - involuntary
- Power - slow + sustained
Outline the morphology, connections, control and power of cardiac muscles
-
Morphology - short branched cylinders
- single central nuclei
- striations - Connections - junctions
- Control - involuntary
- Power - lifelong variable rhythm
What is creatine kinase used for?
To measure and diagnose heart attacks
What could a rise in creatine kinase by due to?
Heart attack
IM injection
Rhabdomyolysis
A fall
Vigorous physical exercise
What are natriuretic peptides?
Peptide hormones that are synthesised by heart, brain and other organs
Atrial natriuretic peptides - atria
Brain-type natriuretic peptides - ventricles
When are natriuretic peptides released?
Where from?
- By heart during heart failure (atrial + ventricle distension)
- LV hypertropy + mitral valve disease BNP
- Congestive heart failure ANP
- Atrial natriuretic peptides - atria
- Brain-type natriuretic peptides - ventricles
What do natriuretic peptides do?
Reduce arterial pressure
- By decreasing blood volume + systemic vascular resistance
- reduce renin release
- vasodilation
What are purkinje fibres?
Specialised myocardial cells which carry impulses to ventricular muscle from AVN to allow ventricles to contract in a synchronous manner
Cellular features of purkinje fibres
Abundant glycogen
Sparse myofribrils
Extensive gap junction sites
Location of smooth muscles
Forms contractile walls of passageways or cavities
What are indicators are muscle injury?
Creatine kinase - all muscle
Myoglobin - skeletal muscle
Troponin I - cardiac muscle
What is an indicatior of skeletal muscle damage?
Myoglobin
What is an indicatior of cardiac muscle damage?
Troponin I
Why is troponin I assay better to diagnose than creatine kinase?
More specific
CK is all muscle
Troponin I is cardiac muscle
- Actin and myosin within **
- Many sarcomeres makes up a **
- Many myofibrils make up a **
- Muscles fibres are packaged into **
- ** between individual muscle fibres
- ** wraps around a fascicle
- ** wraps around many fascicles
- Actin and myosin within sarcomeres
- Many sarcomeres makes up a myofibril
- Many myofibrils make up a muscle fibre
- Muscles fibres are packaged into fascicles
- Endomysium between individual muscle fibres
- Perimysium wraps around a fascicle
- Epimysium wraps around many fascicles
Describe the structure of the three types of muscle cells
skeletal:
- striated
- multi nucleated
cardiac:
- striated
- single central nucleus
- intercalated discs
- branching
smooth:
- non striated
- central nuclei
- spindle shaped
Outline skeletal muscle repair
- cannot divide
- regenerate but mitotic activity of satellite cells
- causing hypertrophy + hyperplasia
Outline cardiac muscle repair
- incapable of regeneration
- fibroblasts invade, divide + lay down scar tissue > fibrosis + loss of function
Outline smooth muscle repair
- retain mitotic activity
- stable cells
