Muscle Anatomy and Physiology Flashcards
What are the three types of muscles?
Skeletal, cardiac and smooth
Define STRIATED MUSCLE TISSUE
Striated muscle tissue features repeating functional units called sarcomeres which are seen as a series of visible bands along the muscle fibres. Movement of these fibres is voluntary, aside from the heart. These muscle tissues fatigue rapidly.
Define SMOOTH MUSCLE TISSUE
Smooth muscle tissue is found within the walls of hollow organs and are non-striated. Movement of these muscles is involuntary and they fatigue slowly.
Define a TENDON
A tendon is a flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone. Most tendons have white collagen which is inelastic.
What is the role of a tendon?
- to connect muscle to bone
What is the structure of a tendon?
It is made of a number of structures that all fit inside one another, which demonstrate how the tendon is able to retain its strength.
Tendon is made up of fascicle, fibril, subfibril, microfibril.
Define the CRIMP
The crimp appears in tendons when collagen fibrils are parallel to each other and closely packed. They show a wave like appears and allow the tendon to have some flexibility. The bigger the crimp is, the more elastic the tendon is.
Define a LIGAMENT
A ligament is a short band of tough, flexible fibrous connective tissue which connects two bones or cartilages or holds together a joint.
What is the sarcoplasmic reticulum?
The sarcoplasmic reticulum is a network of tubules that extend through muscle cells. It regulates calcium concentration in the cytoplasm of striated muscle cells.
Describe smooth muscle
It is regulated by to autonomic nervous system and influenced by hormone secretion. Non striated cylindrical cells with a nucleus.
Describe cardiac muscle
This appears in the heart only and is striated.
Describe skeletal muscle
Used voluntarily. Has many nuclei and is striated.
What are the 4 muscle shapes?
Pennate, circular, parallel and convergent
Describe a pennate muscle
Fibre groups radiate from one point. Fascicles are around 1 central tendon. They are strong but inflexible
Describe a circular muscle
Sphincters, usually a junction. Their role is to open and close to let things in or out.
Describe a parallel muscle
The fibres are parallel to the long axis. Their force is lower, so they are not the strongest, but they allow extension, meaning they can stretch.
Describe a convergent muscle
One where the origin is wider than the insertion.
What is the hierarchy of skeletal muscle?
Skeletal muscles have a hierarchical structure - the organ is comprised of fascicles which are composed of fibres. Fibres are composed of myofibrils. Myofibrils are made up of repeating units called sarcomeres. Sarcomeres are the functional unit of the muscle cell. Actin and myosin are found here.
What are myofilaments?
The sarcomere is made of the myofilaments actin and myosin. Actin is the thin filament and myosin is thick filament. They both work together to allow muscle physiology and movement.
Define a NERVE CELL
A nerve cell is a neurone, and its job is to make messages travel by sending electrical messages that travel across cell membranes.
What is the synaptic system?
- Electric message is sent along the neurone
- It meets the gap (the synapse) and jumps across
- It notifies the next nerve cell to move the message along
What does the CNS control?
The brain (forebrain, midbrain and hindbrain) and the spinal cord.
What does the PNS control?
The somatic (voluntary) and autonomic (involuntary) nervous systems as well as the sympathetic and parasympathetic nervous systems.
What is the function of muscles?
- to produce movement
- to maintain postures and positions
- to keep joints stable
- to control cavity pressure (drawing in/expelling air)
- to maintain body temp. (shivering)
- controls exits and entrances to the body
- energy storage
Define a SARCOMERE
A sarcomere is the functional unit of the muscle cell.
What are the regions of the sarcomere?
- A band, in the middle
- I band is near the edges and is only ever actin
- H band is in the middle of A and is only ever myosin
- Z lines identify the start and the end of the sarcomere
Actin is secured to the Z line by alpha atin and myosin is secured to the Z line by titin.
What is sliding filament theory?
Actin and myosin do not shorten and instead they slide past one another to shorten the sarcomere. As a result, the whole muscle contracts. I band shortens, H band shortens, A band stays the same.
What are the properties of muscle?
Contractibility, excitability, extensibility, elasticity
Define INNERVATION
Innervation is the process of supplying nerves to something.
