8. Muscular System Flashcards
How is cardiac muscle similar to skeletal muscle?
Besides the mechanism of contraction, it also stores calcium, has a sacroplasmic reticulum, many mitochondria and a system of transverse tubules.
How is cardiac muscle similar to smooth muscle?
The mechanism of contraction is essentially the same
What is the function of intercalated disks?
They allow muscle impulses to pass freely so that they travel from cell to cell, triggering contraction.
What characteristic of cardiac muscle contracts the heart as a unit?
when one portion of the cardiac muscle is stimulated, the impulse travels to other parts of the network, cell to cell.
Distinguish between the origin and the insertion of a muscle.
The immovable end of the muscle is the ORIGIN.
The movable end is its INSERTION.
When a muscle contracts, the insertion is pulled towards its origin
Define Prime Mover
The muscle that provides most of the movement, also called agonist.
What is the function of a synergist? An antagonist?
Synergists contract and assist a prime mover so that it’s actions are more effective.
Antagonists resist a prime movers action and cause movement in the opposite direction.
What information is imparted in the muscle’s name?
the muscle’s relative size, shape, location, action, number of attachments, or the direction of its fibers.
Which 6 muscles provide facial expressions?
Epicranius (raises eyebrow) Orbicularis Oculi (closes eye) Orbicularis Oris (closes and protrudes lips) Buccinator (compresses cheeks inward) Zygomaticus (raises corner of mouth) Platysma (draws angle of mouth downward)
Which muscles provide the ability to chew?
Masseter (elevates mandible)
Temporalis (elevates mandible)
Which 3 muscles provide head movements?
Sternocleidomastoid (pulls head to one side, pulls head toward chest or raises sternum)
Splenius capitis (Rotates head, bends head to one side or brings head into upright position)
Semispinalis capitis (extends head, bends head to one side or rotats head)
Which 5 muscles move the pectoral girdle?
Trapezius (Rotates scapula and raises arm; pulls scapula medially or pulls scapula and shoulder downward).
Rhomboid major (raises and adducts scapula)
Levator scapulae (elevates scapula)
Serratus anterior (pulls scapula anteriorly and downward)
Pectoralis minor (pulls scapula anteriorly and downward or raises ribs)
Which muscles move the abdominal wall?
External oblique (tenses abdominal wall and compresses abdominal contents)
Internal oblique (tenses abdominal wall and compresses abdominal contents)
Transversus abdominis (tenses abdominal wall and compresses abdominal contents)
Rectus abdominis (tenses abdominal wall and compresses abdominal contents; also flexes vertebral column
Three types of muscle tissue
Skeletal
Cardiac
Smooth
Broad fibrous sheets of connective tissue that attach to bone or to the coverings of adjacent muscles are called:
Aponeuroses
What is the name of the connective tissue covering the entire muscle
Epimysium
Want connective tissue separates muscle tissue into compartments called fascicles?
Perimysium
One muscle cell is called …
Muscle fiber
What is the region between to z lines called?
Sarcomere
Which two types of protein filaments make up a myofibril?
Myosin and actin
The characteristic striated appearance of skeletal muscle is due to the arrangement of alternating protein filaments composed of…
Myosin and actin
A motor neuron and all the muscle fibers it controls is know as a:
Motor unit
this model describes how the thick and thin filaments slide past each other during contraction:
The sliding filament model
A neuromuscular junction is the connection between a(n) _________ and a skeletal muscle fiber
Motor neuron
What is the name of the neurotransmitter responsible for stimulating muscle contraction?
ACH or acetylcholine
After a muscle impulse is triggered it travels over the surface of the muscle fiber. How does the muscle impulse travel deep into the fiber?
It travels through the transverse tubules to get deep within the muscle fiber
What is a cross bridge?
The binding of actin to myosin
When the cross-bridge of the myosin molecule forms linkages with actin filaments, the result is….
Shortening of the muscle fiber
What is the role of calcium in a skeletal muscle contraction?
It interacts with troponan and tropomyosin to expose binding sites on the actin
What is the major way that muscles become fatigued?
There is a build up of lactic acid that that lowers the pH of the muscle
What are two ways ATP is used in muscle contraction?
Provide power to “cock” the myosin cross-bridge
To release the linkage between actin and myosin
What are two things that lead to muscle relaxation?
Acetylcholinesterase must decompose acetylcholine
Calcium is pumped back into the sacroplasmic reticulum
Which molecule makes it possible for cells to regenerate ATP from ADP?
Creatine phosphate
What two molecules can provide oxygen to muscle cells in order to generate adequate ATP for muscle contraction?
Hemoglobin
Myoglobin
Want acid is a common cause for muscle fatigue?
Lactic acid
Cardiac muscle stores less calcium than skeletal muscle but they are able to get extra calcium from the extracellular fluid that travel through the transverse tubules. True/false?
true
Striations are only present on skeletal muscle. True/false
False
Cardiac muscle stores less calcium than skeletal muscle, but they are able to get extra calcium from the extracellular fluid that travel through the transverse tubules
True
Striations are only present on skeletal muscle. True/false
False
Smooth muscle contains actin and myosin filaments that are arranged very similarly to how they are arranged in skeletal muscle. T/F
False
The two types of muscle that have an involuntary mode of control are….
Smooth muscle and cardiac muscle
T/F Smooth muscles have many nuclei but lacks striations
False
T/F skeletal muscles have a well developed transverse tubule system
True
