9. Muscle Tissue Structure And Function Flashcards
What are the 2 types of striated muscle?
Skeletal
Cardiac
Is myoglobin present in any of the 3 muscle types?
In skeletal and cardiac, not smooth
Are the muscles voluntary or involuntary?
Skeletal is voluntary
Cardiac and smooth is involuntary
What is myoglobin?
Red protein, similar to subunit of haemoglobin
Stores oxygen
No cavity for CO2
What happens when striated muscle dies?
Myoglobin is released into the blood
What is the sarcolemma?
Outer membrane of muscle cells (like the plasmalemma)
What is the sarcoplasm?
Cytoplasm of muscle cell
What is the sarcosome?
Mitochondrion
What is a sarcomere?
Contraction unit in striated muscle
What is the sarcoplasmic reticulum?
Smooth endoplasmic reticulum of muscle cell
Contains Ca2+ for contraction
What is each fascicle surrounded by in skeletal muscle?
Perimysium
Is skeletal muscle uni or multinucleated?
Multinucleated
What is a striated muscle cell called?
Muscle fibre
What are myosin, actin and titin?
Actin in think filament
Myosin is thick filament
Titin acts as spring, pulls actin back to position
What are slow twitch muscle fibres?
Type 1 Red Rich capillary supply Aerobic Lots of myoglobin, mitochondria and cytochromes Endurance type activities
What are intermediate twitch fibres?
Type 2A Red to pink Rich capillary supply Aerobic Lots of myoglobin Many mitochondria and cytochromes Assist type 1 and 2B activities
What are fast twitch fibres?
Type 2B White Poor capillary supply Anaerobic Low myoglobin, mitochondria and cytochromes Strength activities
What are intercalated discs?
In cardiac muscle for electrical and mechanical coupling with adjacent cells
What are the 2 peptides that are released by the heart during heart failure and what do they do?
ANP (atrial natriuretic peptide) - released by atria
BNP (brain-type natriuretic peptide) - released by ventricles
Reduce arterial pressure by decreasing blood volume and resistance
What is hypertrophy?
Enlargement of individual cells
What is atrophy?
Shrinking of individual cells
What is hyperplasia?
Multiplication of cells
Where is the nuclei located in cardiac muscle cells?
In centre
Where is the nuclei located in skeletal muscle cells?
Peripheral
Where is the nucleus located in smooth muscle cells?
Centre, large nucleus
What stimuli do smooth muscle cells respond to?
Nerve signals
Hormones
Drugs
Local concentrations of blood gases
How can skeletal muscle be repaired?
Can regenerate by mitosis of satellite cells (stem cells)
Satellite cells also fuse with existing muscle cells to increase mass
How are cardiac muscle cells repaired?
Adult is incapable of regeneration
Scar tissue forms instead
How are smooth muscle cells repaired?
Retains mitotic activity, can form new cells
E.g. in pregnant uterus
