Muscle and nervous tissue Flashcards
What is the main purpose of muscle tissue?
To convert ATP into use movement
How much of the body is made of muscle?
~50% of mass
What are the functions of muscle tissue?
Produces body movement, maintains posture and generates heat
What are the red types of muscle tissue?
Skeletal, Cardiac, Smooth
How many name skeletal muscles are there?
~650
Where is skeletal muscle found and how is it attached?
Attached onto bones by tendons
What does skeletal muscle look like under a microscope?
Striated cylindrical long cells that are multi nucleated, nucleus is pushed to the side
Is skeletal muscles conscious or unconscious control? voluntary or involuntary? Give an example
It is voluntary but not always conscious, e.g. posture is voluntary but it is involuntary
What is the smallest and largest muscle in the body? What are their sizes?
Stapedius = 1.25mm Sartorius = 60cm
What is the function of the stapedius muscle? What can cause it to not work? What happens when it doesn’t work properly?
Adjusts the way sound travel into your ear,
A viral infection can cause Bell’s palsy when the muscle doesn’t work causing hyperacusis (everything sounds loud)
Where is the Sartorius and what motion does it control?
It is from the hip to the tibia across the front of the thigh
helps leg rotate inwards
What is the reason for the striation of skeletal muscle fibres?
Due ot eh highly organised arrangement of myofibrils within the cells
What are myofibrils?
Filaments that fill the sarcoplasm (cytoplasm of striated muscle cells)
What are the types of filaments that make up myofibrils? Describe them
Thin filaments: mostly actin, 8nm diameter, 1-2μm long
Thick filament: myosin, 16nm diam, 1-2μm long
How are myofilaments arranged?
In compartments of sarcomeres
What is a sarcomere?
The basic functional unit of a myofibril
What separates sarcomeres from each other?
Z discs
What is the organisational level of muscle tissue?
Many sarcomere make up myofibril, these myofibril are packed together into a sucre fibre/cell. These muscle fibres are bundled together to form a fascicle. Multiple fascicles are bound together to form skeletal muscle
What is the composition of a sarcomere?
Thick filaments are in the middle and thick filaments slide over these and are attached to Z discs. M line is in the middle of the sarcomere and holds the thick filaments together and attic filament runs through the sarcomere to and from the Z disc
What is the full structure of skeletal muscle?
Myofibril make up the muscle fibre/cells. Endomysium coasts the muscle fibre. Muscle fibres are bundled together to form a fascicle and is coated by perimysium. Fascicle’s are bundled together to form the skeletal muscle. These muscle tissue is bound by epimysium and this then attaches onto the bone with tendons
What is the purpose of outer sheaths on each organisational level of muscle tissue?
Separates them from each other (e.g. separates muscle tissue, different muscles from each other) so they can slide over each other
What are the different bands in a sarcomere?
A band I band H zone Z disc M line
What is the A band?
Dark middle park that contains full length of the the thick filament (therefore includes the overlapping thin filaments)
What is the I band?
thin filaments excluding the overlapping thick filaments
What is the H zone?
Central zone where there are only thick filaments and no overlapping thin filaments
What is the Z disc? What is its function?
Plat of dense material within the I band
separates the sarcomeres
Where is the M line? What is its function?
In the middle of the sarcomere
Holds the thick filaments together
Where is the cardiac muscle found?
Only in the heart
What would cardiac muscle look like under a microscope?
Striated and branched with a single central nucleus connected with intercalated discs
What do the intercalated discs contain? What are the functions of these components? What is the function of the intercalated discs?
Desmosomes: bind intermediate filaments and provide adhesion in contraction
Gap junctions: communication for co-ordiated rapid conduction
It is to provide rapid communication channels in the hearts for co-ordinated contractions
What other types of tissue other than cardiac tissue can you find intercalated discs?
You can’t, they’re only found in cardiac tissue
Where can you find smooth muscle tissue? Give examples
In the walls of hollow internal structure, e.g. blood vessels and intestines
What would smooth muscle tissue look like under a microscope?
no striations, single nucleus per fibre, short small and spindle shaped (30-200μm long, 3-8μm thick in middle)