Muscles Flashcards
(26 cards)
Focus on functional groupings and the large, key
muscles with familiar names (biceps brachii, triceps brachii,
quadriceps femoris etc.)
- List and explain the four unique properties of muscle tissue
- Identify the many roles (functions) of skeletal muscle in the body.
- Describe the levels of organisation in a skeletal muscle.
- Explain how and where muscles are attached to other body structures.
- Detail the components of muscle fibres.
- Describe the four organisational patterns in fascicles.
- Compare skeletal, cardiac and smooth muscle
- Explain how muscle names incorporate appearance, location, function,
orientation, and unusual features. - Identify the major muscles involved in: facial expression, mastication,
movement of the vertebral column, respiration (later in semester),
abdominal wall, movements of the upper and lower limb.
what are the four unique characteristics of muscle tissue
excitability: muscle cells are responsive to input from stimuli
contractility: stimulation of muscle fibre can lead to contraction and shortening of the muscle fibre
elasticity: a contracted muscle cell can return to resting length when applied pressure is removed
extensibility: the ability of a muscle fibre to be stretched beyond the ability of its rested length
what are the three types of muscle
skeletal, smooth and cardiac
characteristics of skeletal muscle tissue
each skeletal muscle is considered an organ
they contain all four tissue types
they are striated (marked with long, thin, parallel streaks)
and they are usually attached to bones
the functions of skeletal muscle tissue
- body movement
- maintanence of posture
- temperature regulation
- storage and movement of materials
- support
what is skeletal muscle comprised of
- muscle cells ( muscle fibres)
Each muscle fibre runs the length of the entire muscle - blood vessels
- organised nerves
what are the components of connective tissue
each muscle has three layers of concentric connective tissue composed of collagen and elastic fibres
this connective tissue provides protection, sites for blood vessel and nerve distribution, and a means of attaching the muscle to the skeleton
what are the components of connective tissue
- endomysium (endo = within, myo = muscle): the innermost layer that surrounds and electrically insulates the muscle fibre
areolar connective tissue - perimysium (peri = around): surrounds the fascicles
- epimysium (epi = upon): surrounds the entire muscle
is dense irregular connective tissue
deep fascia surrounds each muscle and separates muscle from each other
superficial fascia separates muscle from skin
terminology of muscle fibre
skeletal muscle fibre have many of the same components found in a typical cell, however they are also sometimes named differently.
list three typical cell names and their respective muscle fibre name
plasma membrane = sarcolemma
cytoplasm = sarcoplasm
smooth ER = sarcoplasmic reticulum
what does ‘sarco’ mean in muscle fibre terminology
flesh
describe cardiac muscles and give an example of where it is found
Cardiac muscles are found in the wall of the heart.
They are striated and form Y branches. They have one or two nuclei, are under involuntary control,
Cardiac muscle is autorhythmic, and doesn’t require nervous stimulation to generate a muscle impulse.
Describe smooth muscles and give two examples of where they are found
found in the walls of blood vessels and viscera, and walls of hollow organs (intestines)
they have short fusiform cells (which are wide in the middle and taper toward the ends)
there is one centrally located nucleus, it is not striated, thin filaments attach to dense bodies, and is under involuntary control
what are muscle attachments
- at the end of a muscle, all the connective tissue merge to form a tendon, which connects muscle to bone, skin, or another muscle
- muscles typically extend over a joint and connect to both articulating bones of a joint
- when a muscle contracts, one of the articulating bones will move more than the other. the less moveable point is the origin, and the more moveable point is the insertion.
describe a tendon
typically has a cordlike appearance
what is isometric contraction
length is constant - tension is changing
muscle tension is less than the resistance.
there is tension, but the muscle does not shorten, and no movement occurs
what is isotonic contraction
tension is constant - length is changing
muscle tension is the same as or more than the resistance.
the muscle shortens and there is movement
what are two types of isotonic contraction
concentric contraction where the muscle is shortening
eccentric contraction where the muscle is lengthening
what are the four different skeletal muscle fascicle arrangements and provide an example of each
- circular; mouth
- parallel; rectus abdominis
- convergent; pectoralis major (converges to one attachment point)
- pennate
unipennate; extensor digitorum
bipennate; rectus femoris
multipennate; deltoid
what are the three actions of skeletal muscles and provide an example of each
- agonist; produces a specific movement when it contracts
The triceps brachii is the agonist that causes forearm extension - antagonist; opposes the action of an agonist muscle
The biceps brachii is an antagonist to the triceps brachii - synergist: a muscle that assists the agonist in movement
the anconeus assists the triceps brachii in extending the forearm
how are skeletal muscles named
there is several criteria for naming muscles. the following is a list;
- muscle action
- specific body region
- muscle attachments
- orientation of muscle fibres
- muscle shape and size
- muscle heads/tendons of origins
what muscles aid in facial expressions and mastication
provide an example of each
axial muscles
Orbicularis oculi assists in closing and opening the eye
The pterygoid muscle causes side-to-side movement during chewing.
what are the two major muscle groups responsible for moving the vertebral column
erector spinae* and the transversospinalis group
what are the muscles involved in inhalation and exhalation (respiratory system)
external and internal intercostals, the transverse thoracis, the scalenes and the diaphragm
