Flashcards in Muscular System Deck (45)
What is myalgia?
What is Myocardium?
Muscular component of the heart
What is myasthenia?
Weakness of the muscles
What is Myopathy?
Any disease of the muscle
What is Myoclonus?
A sudden spasm of the muscles
What is a sarcolemma?
The outer membrane of the muscle
What is the sarcoplasm?
The cytoplasm of the muscle
What is the sarcoplasmic reticulum?
The smooth endoplasmic reticulum of a muscle cell
What are the three types of muscle?
What is the difference between red, intermediate and white muscle fibres?
Red have the smallest diameter, many mitochondria, contact slowly, repetivie and weak, fatigue slowly, few ATP-ases, in limbs of animals
Intermediate- in the middle
White- opposite and in Extraocular muscles (eye)
What is myoglobin?
Red protein with Haem
not present in smooth muscle
Diving animals have lots of myoglobin so can submerge for longer
Haemoglobin gives up oxygen to myoglobin
What causes the mobility of the tongue?
Multidirectional orientation of the tongue and plasticity and strength of connective tissue
What is atrophy of muscles?
Muscles fibres are destroyed more than replaced
What is hypertrophy of muscles?
Muscle fibres are replaced more than destroyed
What causes Atrophy?
Disuse- Not moving limb- loss of protein reduced fibre diameter, loss of power
Denervation- signs of ;power motor neurone lesions
What causes Hypertrophy?
More protein, increased diameter- exercise
How can more sarcomeres develop?
Increased by frequent stretching
What is MHAZI?
M line inside H zone
H zone inside A band
A band is inside the two Z discs
Z disc is inside the the I band
What are Troponin assays useful for?
Marker for Cardiac ischaemia (heart attack)
must measure in 20 hours
not proportional to degree of damage
What is Creatine Kinase used for?
Diagnose cardiac ischaemia (heart attack)
proportional to degree of damage
Can result from many reasons so Troponin used more
caused by- exercise, fall etc
What is the sliding filament model?
Actin filament (thin filaments)
Myosin (thick filaments)
Myosin heads form cross bridges with actin filaments exert force on them to move
Contraction begins when an ATP bound to myosin is hydrolysed to ADP and P
This causes myosin head to extend
Power stroke occurs- shortening sarcomere
ATP binds which caused the Myosin head to become unattached
When muscle is relaxed Tropomyosin blocks the binding sites, if calcium is present it binds to troponin which moves the tropomyosin
What are the events lead to contraction of a skeletal muscle?
1. nerve impulse arrives at neuromuscular junction
2. ACh is released into synaptic cleft causing local depolarisation of the sarcolemma
3. Na+ channels open and Na enter cells
4. General depolarisation occurs and spreads over the sarcolemma and into T tubules
5. Voltage sensor proteins in T tubules change their conformation
6. Gated Ca2+ are opened
7. Ca is released from the terminal in to the sarcoplasm
8. Ca2+ binds to the troponin
9. contraction initiated and ca returns
Where are nuclei positioned in cardiac muscle?
What is present is skeletal muscle that isn't present in cardiac muscle?
What are gap junctions in cardiac muscle used for?
What are Adherens-type junctions used for in cardiac muscle?
anchor cells and actin filaments
What is cell hypertrophy?
Enlargement of cell
What is cell Hyperplasia?
Multiplication of cells
What is heart Atrophy?
Heart is smaller than normal size