Muscles Flashcards
(43 cards)
Three types of Muscle
Smooth, cardiac, skeletal
define myofilaments
Myofilaments are threadlike structures that comprise the myofibril inside the muscle cell (or muscle fiber). There are two main types of myofilaments: (1) thin filaments and (2) thick filaments. In a skeletal muscle, the myofilaments are arranged in a repeating pattern of light and dark bands.
Threadlike structure of muscle fibres (cells)
Thin and thick filaments
Repeating light and dark banks
Define sarcomere
A sarcomere is the basic contractile unit of muscle fiber. Each sarcomere is composed of two main protein filaments—actin and myosin—which are the active structures responsible for muscular contraction. The most popular model that describes muscular contraction is called the sliding filament theory.
Active vs myotin
Actin is a group of globular proteins that are the most abundant proteins in most eukaryotic cells and help in providing shape, structure, and mobility to the body. Myosin is a family of motor proteins that, together with actin proteins, form the basis for the contraction of muscle fibers
3 main functions of muscles
Movements, posture, heat production
other muscle functions
Storage of substances e.g. glycogen and oxygen
Movement of substances
Hemoglobin vs myoglobin
Hemoglobin is a heterotetrameric oxygen transport protein found in red blood cells (erythrocytes), whereas myoglobin is a monomeric protein found mainly in muscle tissue where it serves as an intracellular storage site for oxygen.
do arteries and veins have muscles?
Yes, these help to move blood around the body
Define a wave of contraction
Peristousis, a movement where
4 main muscle properties
Contractibility - shorten
Excitability - can conduct electrical current i.e. nerve impulse
Extensibility - stretch without damage
Elasticity - spring back to original location
Striated vs non-striated muscle
striated: muscle cells that are lines up parallel to one another. a strict contraction e.g. in the heart, bicep - a uniform contraction. Skeletal and cardiac
Non-striated: no visible stripes, can run in other unusual directions. Smooth muscle
Which muscle is auto-rythmic and what does this mean?
Cardiac muscle generates their own rhythmic contraction
where can you find smooth muscle
blood vessels, walls of the gut and the iris (coloured part of the eye)
Which muscles are striated
Cardiac and skeletal
Name 2 involuntary muscles
Cardiac and smooth
how many skeletal muscles in the body?
640
What % of our body weight is muscle?
40%
What is fascia?
skeletal muscle is covered by fascia - a dense connective tissue that organises muscle, secures it to skin and provides stability
What is the major component of fascia?
Collagen
What are myocytes?
Myocytes are the cells within the heart tissue that generate the tiny electrical impulses that cause heart muscle cells to contract, and the heart to ‘beat.
Define sarcolemma function
As the muscle cell membrane, the sarcolemma functions as a barrier between the extracellular and intercellular parts of the muscle fiber cells.21 Jul 2021
Define a Z line
What is the Z-line anatomy?
The structure indicated is the Z-disc/Z-line formed between adjacent sarcomeres. A sarcomere is the name given to the basic unit of muscle, composed of sliding protein filaments of actin and myosin. The thinner actin filaments are all bound to the Z-line, which makes up the boundary of the sarcomere
What is sarcoplasmic reticulum
The sarcoplasmic reticulum (SR) is a type of smooth endoplasmic reticulum that abounds in the myocyte (muscle cell). In myocytes, it can be seen as a membrane-bound structure inside the myocyte, containing calcium ions. The network of tubules extends throughout the myocyte.
What is acetylcholine
Acetylcholine is a chemical messenger, or neurotransmitter, that plays an important role in brain and muscle function.
