Muscle Tissue Flashcards
What are the functions of Skeletal muscle?
Movement Maintenance of posture Support soft tissues Sphincter function Thermoregulation
Describe the Cells of skeletal muscle?
Large multinucleated cells (fibres)
Describe formation of skeletal muscle?
Fused myoblasts surrounded by loose connective tissue (contain collagen and elastin fibres) merge into the tendon at sites of muscle attachment
Describe Muscle Fibres?
Non-dividing cells surrounded by satellite cells
What is Muscle Cell Membrane called?
Sarcolemma
What type of Tissue in Skeletal muscle?
Striated Voluntary muscle
What are Satellite cells?
Undifferentiated muscle stem cells with regenerative potential
What is the Function of Satellite cells?
Reserve that can be activated to replace or increase muscle
What is Muscle composed of?
1) muscle fibre (fused myocytes) surrounded by endomysium
2) Bundles of 1 form of muscle fascicle surrounded by perimysium
3) Bundles of 2 form muscle surrounded by epimysium
What is Inside the Muscle fibre?
Myofilamets - thin filaments (actin, tropomyosin, troponin) and thick filaments (myosin)
Bundles of 1 form myofribrils surrounded by sarcoplasmic reticulum
Describe Function Transverse Tubules?
Form tunnels through muscle fibre and encircle myofibrils, conduct AP for initiation of contraction
What is a Sarcomere?
Smallest functional unit of muscle
Describe Z band?
Bound sarcomere, formed by protein that supports the thin filaments
Describe I bands?
Light in appearance , consist of thin filaments
Describe A bands?
Dark in appearance, consist of thick filaments
Describe M line?
Consist of proteins supporting the thick filaments
Describe the H zone?
Contains thick filaments only
Describe the Zone of Overlap?
Contains both thick and thin filaments, contraction achieved by sliding motion between both filaments
What are the differences between Cardiac and Skeletal muscle?
Only found in Heart (cardiocytes)
Not fused (single nucleus) branched
Smaller than skeletal muscle fibres
Describe Cardiac muscle?
Intercalated discs at end of cardiocytes
Convolutions of sarcolemma between cardiocytes with gap junctions and desmosomes
What can the Cardiac muscle do?
Stabilise the tissue by exchanging ions and small molecules allowing spread of action potentials
Why can Cardiac muscle cause Medical problems?
No regeneration of Cardiocytes which is why heart muscle can slowly degenerate with age
What cells in Cardiac muscle stimulate Contractions?
Pacemaker cells, nervous system can only alter rate of activity
What kind of Muscle is Cardiac muscle?
Striated Involuntary muscle
Where can Smooth muscle be located?
Cardiovascular system Skin Respiratory system Digestive Urinary Reproductive
Describe Structure of Smooth muscle cells?
Small, slender, tapering with a single nucleus (not fused)
No sarcomeres
Where are the Sarcomeres in Smooth Muscle Cell?
Actin and Myosin are scattered throughout the cell
Where is the Thin filament in the Smooth muscle?
Anchored to dense bodies located underneath the cell membrane
Where is the sites of the Cell-Cell attachment?
Outside of cell along with matrix proteins and connective tissue
What is Smooth muscle capable of?
Division and tissue regeneration, can trigger own contractility or be innervated
What is Smooth muscle known as?
Non-striated Involuntary muscle
