Muscle Tissue Flashcards
What are two other names for muscle cells?
Muscle fibres and Myocytes
What is the purpose of muscle?
To convert ATP (energy molecule) into a force
What are the 3 types of muscle?
Skeletal, Cardiac and Smooth Muscle
Skeletal muscles are attached to bones by ___
Tendons
How do skeletal muscles appear under the microscope?
Striated - Striped, with the nuclei stuffed to the side of the cell
Is skeletal muscle under voluntary or involuntary control?
Usually voluntary
What shape are skeletal muscle fibres?
Cylindrical
What is the smallest skeletal muscle, where is it, and how long is it?
Stapedius, in the inner ear, stabilising the stapes bone, 1.25mm long
What is the longest skeletal muscle, where is it, and how long is it?
Sartorius, from the hip to the knee, acting as a knee flexor, up to 60cm long
How long can skeletal muscle cells be?
Between 1mm-30cm+
Are skeletal muscle cells multinucleate?
Yes, many peripheral nuclei pushed to the side
What are the functions of skeletal muscle?
Posture, Motion, Heat Production and Protection
What is the cell membrane of a muscle cell called?
Sarcolema
What is the cytoplasm of a muscle cell called?
Sarcoplasm
What are the tubular structures within a muscle cell?
Myofibrils
In relation to the length of the muscle cell, how long are myofibrils
They extend the full length of the muscle cell
What are the two types of filaments in a Myofibril?
Thin and thick myofilaments
What are thin myofilaments made of?
Actin
What are thick myofilaments made of?
Myosin
Do myofilaments extend the full length of the cell?
No
What are the repeating compartments of myofilaments called?
Sarcomeres
What are the “borders” of a Sarcomere?
Z discs/lines
What layer of connective tissue surrounds anatomical muscle?
Epimysium
What does the Epimysium do?
Prevents muscles from sticking together and gives them structure
What is a fascicle?
A group of muscle cells within a muscle
What surrounds fascicles?
Perimysium
What layer surrounds individual muscle cells (not the sarcolema)?
Endomysuim
Where are capillaries and nerves found in the muscle?
In the endomysuim surrounding each cell
What part of the sarcomere contains all the thick myofilaments (including some thin filaments)?
A Band
What part of the sarcomere only contains thin myofilaments?
I Band
What part of the sarcomere only contains thick myofilaments?
H Zone
Where is the M Line?
In the middle of the sarcomere
What does the M Line do?
Hold thick myofilaments together
Does the Z Disc/Line go through the I band?
Yes
What is the Z Disc/Line made of?
Actinins
What do Actinins do between sarcomeres?
Link the thin myofilaments between sarcomeres
Is Cardiac muscle striated?
Yes
What is the shape of cardiac muscle?
Branched
How do cardiac muscle cells join together end-to-end?
Through intercalated discs
What junctions do intercalated discs contain?
Desmosomes and Gap Junctions
Where is cardiac muscle found?
In the heart
Where are cardiac muscle nuclei found?
In the centre of the cell
Is cardiac muscle under voluntary or involuntary control?
Involuntary
Is smooth muscle striated?
No
Where are smooth muscle cells found?
In the walls of hollow internal structures (Intestines, Blood vessel walls, etc.)
What is the shape of smooth muscle cells?
Short, small, spindle-shaped
Is smooth muscle under voluntary or involuntary control?
Involuntary
In smooth muscle cells, thin and thick myofilaments attach to what?
Dense bodies
Functionally, dense bodies on smooth muscle cells are similar to what?
Z Discs/Lines
What is a major protein in Dense bodies?
Actinin
What are the non-contractile elements that also connect to dense bodies in smooth muscle cells?
Intermediate filaments
Due to the presence of intermediate filaments on smooth muscle cells, the cell can’t ___ when contracting, but instead it ___
collapse, twists
Where are smooth muscle nuclei found?
In the centre of the cells
