Clin Phys Week 1 E Flashcards
What does epimysium cover?
Entire muscles
What does perimysium cover?
Fascicles (bundles of muscle fibres)
What does endomysium cover?
Muscle fibres (cells)
What are the micro structures of muscles?
Myofibres (Muscle cells)
Intracellular proteins (myofilaments)
Myofibrils (made of long lengths of sacromeres)
Sacromeres (smallest functional unit of a muscle)
What are the universal characteristics of muscle tissue?
Responsiveness
Conductivity
Contractility
Extensibility
Elasticity
What is responsiveness?
The capability of the muscle to respond to chemical signals, stretch or other signals and responding with electrical changes across the membrane
What is conductivity?
Local electrical charge triggers a wave of excitation that travels along the muscle fibre
What is contractility?
The muscle fibre is shortened when stimulated
What is extensibility?
The muscle fibre is capable of being stretched
What is elasticity?
The muscle fibre returns to its original resting length after being stretched
What is the sarcolemma and what are it’s features?
The muscle cell membrane (similar to plasma membrane of normal cells)
It forms a layer over the outside of the cell on the exterior surface of the muscle. It has transverse tubules (t-tubules) extending deep into the muscle cell in order to be in contact with all myofibrils of the muscle. It does this so that it can effectively activate all muscle fibres as it is used to propagate the action potential.
What is the sarcoplasm?
The muscle cell cytoplasm. It is filled with myofilaments organised into sacromeres/ myofibrils.
What is the sarcoplasmic reticulum? What are it’s features?
The equivalent of the smooth endoplasmic reticulum for muscle cells.It comprises of 2 parts:
tubules: hollow pipes which run perpendicular to t-tubules of the sarcolemma
terminal cisternae: large end chambers of the sarcoplasmic reticulum that join the t-tubules.
The sarcoplasmic reticulum contains calcium, which is essential for skeletal muscle contraction. One t-tubule and 2 terminal cisternae form one triad.
What are the myofilaments?
There are 2 types of myofilaments:
Contractile filaments:-actin-myosin.
Regulatory proteins:-troponin-tropomyosin
What is a sarcomere?
It is the functional contractile unit of the muscle. One myofibrils is made of a chain of many sarcomeres.It is a specific arrangement of contractile and regulatory proteins.
