Muscular System Flashcards
Muscules
What are the types of muscular tissue
smooth, skeletal, caridac
What are the 4 special properties of muscle tissue
excitability, contractility, extensibility, elasticity
Elasticity vs Extensibility
Elasticity is the ability of muscle cells to go back to original shape/ length after contraction or extension
Extensibility is the ability of muscle cells to stretch without damage
Contractility vs Excitability
Excitability is the ability of muscle cells to go from polarized to depolarized and vice versa
Contractility is The ability for muscle cells to respond to electrical signal (AP) by contracting
Majority of muscle cells develop from ________ however some muscle cells that turn into smooth muscle develop from _______.
mesoderm, ectoderm
_________ cells recieve signals to differentiate into ______ depending on signals they will differentiate into cardiac, skeletal, or smooth muscle.
mesoderm, myoblasts
Muscle cells are all long which is why they are also called _______ ______. Another name for this cell is ________.
muscle fiber, myocyte
What are the characteristics of smooth muscle? appearance, connection of cells, control by what, found where
Spindle-shaped, no striations, gap junctions (cells touching each other), under ANS control, hormones released by endocrine glands stimulate contraction
Found in walls of esophagus, stomach, intestines, hollow organs
Why does smooth muscle not have striations?
The contractile proteins (thin/thick filaments) are not arranged in organized way
Ways that smooth muscle can be organized/connected? myogenic or neurogenic control?
Smooth muscle can be organized as single-unit or multi-unit. Single unit is connected w/gap junctions so the AP can pass quickly from one cell to the other and contract at once in the walls of visceral organs. Is under myogenic control and neurogenic control.
Visceral muscle answers to hormones. Stretching of hollow organ stimulates single unit smooth muscle.
In multi-unit smooth muscle there are rarely any gap junctions meaning that they are not electrically coupled, each specific cell has to be stimulated individually. Is under neurological control
myogenic vs neurogenic control
myogenic- stimulus from inside of the muscle
neurogenic- controlled by nervous tissue/ Nervous system
Where is multi-unit smooth muscle found
iris, ciliary body, arrector pili, wall of large blood vessels, wall of small airways
What are the characteristics of cardiac muscle? appearance, connection of cells, control by what, found where
slightly striated, single nucleus, branched, communicate by intercalated discs (there are desmosomes holding cells together within discs and gap junctions that allow electrical signal to flow from one cell to the other) (wave like contraction—–> heart contracts——-> eject blood in 1 direction)
cardiac muscle cells are also called ________ _______ and are able to _______ on their own in a specific amount of times/min. Cardiac muscle is under ______ control ONLY therefore it is not controlled by the ______ ______ , it only modulates the times/min our heart contracts.
pacemaker cells( have autorythmicity), depolarize.
myogenic, nervous system
Cell division does not happen for what type of muscle cells and why not?
Cardiac muscle cells and skeletal muscle cells cannot perform cell division after we are born
Cardiac cells have intercalated disc so they cannot divide
a skeletal muscle cell is formed from the fusion of several myoblasts once fused they can divide anymore
What are the functions of muscle tissue
store and move substances ( muscles make up walls of hollow organs)
voluntary body movement
maintenance of body posture
heat production (contraction generates heat)
What is necessary for muscle contraction
calcium, threshold stimulus, ATP
What are the characteristics of skeletal muscle? appearance, connection of cells, control by what, found where
Striated muscle (organized arrangement) , multinucleated, neurogenic control, found in skeletal muscles, voluntary control
What is the unit of striated muscles arranged inlines? What does it consist of?
sarcomere consists of dark (a-band) and light (I-bands)
A row of sarcomeres is a ________. Between each sarcomere is a _______ that defines the end of each unit and anchors ________ therefore it will also ______ during contraction, ________ the whole length of the unit
myofibril, z-line
actin filaments, shorten, decreasing
The A-band is also called ________ and it contains lots of _______.
The I-band is also called __________ and it contains lots of _______.
The _______ or _______ is the center of the A-band and it is where there is only _______ present and no _______. The protein anchoring myosin in H-band is called ________.
Dark band, myosin
light band, actin (thin) (I light chicks and I cannot lie)
h-band, halo area, myosin and no actin
M-line
What are regulatory proteins, their functions, and location?
Tropomysoin and troponin are located in actin filament
tropomyosin covers the myosin binding site, what keeps tropomyosin on binding site is troponin.
when troponin binds to CA it changes shape and moves tropomyosin out allowing myosin to bind
Plasma membrane in muscle cells is _____ which is filled with ______while the cytoplasm is called ______ which contains _____.
sarcolemma (interstitial fluid), sarcoplasm (glycogen and myoglobin)
The sarcolemma invaginates going through the skeletal muscle cell in a transverse way, these invaginations are called __________. On the sides of the structures are _______ that are containers for ______. 1 _____ + 2_____= 1 triad
t-tubules.
terminal cistern, calcium
1 t-tubule+ 2 terminal cistern= triad
Skeletal muscle contraction pathway
Voltage gated calcium channels in presynaptic cell open causing calcium to bind to vesicles and release ACh. ACh leaves terminal buttons goes through synaptic cleft then binds to ligand gated Na channels causing Na to be released causing a change in voltage (depolarization) that open voltage gated Ca channels in terminal cistern, the Ca binds to troponin and it changes shape removing tropomyosin from myosin binding site so myosin can bind and cause contraction. Myosin needs 1 ATP to bind and form cross-bridge with actin and 1 ATP to release the binding site.
https://www.google.com/url?sa=i&url=https%3A%2F%2Fcourses.lumenlearning.com%2Fwm-biology2%2Fchapter%2Fneural-stimulation-of-muscle-contraction%2F&psig=AOvVaw0QcW4HdwMvtavmOdb5-N9v&ust=1711392744127000&source=images&cd=vfe&opi=89978449&ved=0CBIQjRxqFwoTCJDZsPfIjYUDFQAAAAAdAAAAABAD
Where is calcium kept in skeletal muscle cell?
sarcoplasmic reticulum (Endoplasmic reticulum)
What protein stores oxygen within muscle?
myoglobin
Mitochondria needs glucose and oxygen for ATP production. High endurance muscles require large amounts of oxygen therefore they have many ______ that carry oxygen which make the muscle ______ than other muscles.
These muscles have lots of mitochondria and myoglobin. Myoglobin is reg-pigmented so have many of these makes muscle darker.
Myofibrils are filled from what types of proteins? All proteins have what capabilities in common?
contractile(generate force during contraction:myosin/actin) , regulatory(tropomyosin/troponin), and structural proteins( keep thick/thin filaments aligned)
All give extensibility and elasticity, all link myofibrils to sarcolemma and extracellular matrix
Skeletal muscle consist of body connected by ____ to the skeleton. These structures are a fusion of the _______, _______, and _______ fused to periosteum of the bone.
tendon
endomysium, perimysium, epimysium
_________ surrounds a group of myofibrils forming a muscle fiber. _______ surrounds bundles of muscle fibers forming a fascicle. _______ binds fascicles together forming muscle belly or muscle tissue. All merge to form _______.
endomysium, perimysium, epimysium
tendons
Tendons are __________ connective tissue. They attach _______ to ______. They are minimally _____ and consist of ________ while lacking ______ cells
dense, regular
minimally vascular
consist of collagen fibers
lack muscle cells
origin vs insertion
point of attachment that remains stationary -origin
point of muscle attachment that is moveable
How do muscles get bigger and what is this called
increasing myofibrils in in skeletal muscle cells
hypertrophy
List in order the components of a skeletal muscle from outermost to inner
fascia, epimysium, fascicle, perimysium, muscle fiber, endomysium, myofibril
define fascia and its function
protective sheath made up of dense irregular connective tissue it surrounds, supports, and protects every organ, blood vessel, bone, nerve fiber, and muscle in place
The most abundant muscle type in the body are ______ muscles, they can either be ________ or ________.
parallel (fascicles running straight down not at an angle), fusiform, non-fusiform
Examples of non-fusiform parallel
and fusiform, parallel muscles
non-fusiform: sartorius
fusiform: biceps femoris, biceps brachii
Unipennate vs. Bipennate vs. Multipennate
pennate- tendon running down length of muscle w/fasicles running at an angle
unipennate- extensor digitorum, flexor pollicis longus
bipennate- rectus femoris
multipennate-deltoid
Convergent muscle +examples
all fascicles are converging to single point of attachment
pectoralis muscles (major)
Circular muscle +examples
fascicles arranged in a concentric way like circles around an opening
orbicularis oris, orbicularis oculi
Agonist vs. synergist
synergist is same movement as agonist however it is not the prime mover (helps the agonist) (ex. brachialis, brachioradialis)
