Muscles Flashcards
types of muscles that are striated
Cardiac and skeletal
Which type of muscle has branching cells
cardiac muscle
what is a single cell of skeletal muscle called
a muscle fiber
sarcolemma
thin plasma membrane that surronds skeletal muscles
spindle shaped sells that form sheets of muscle
smooth muscle
muscle type with one nucleus
smooth
location of smooth muscle
walls of hollow organs
location of cardiac muscle
heart
Location of skeletal muscle
attached to bones and occasionally skin
Function of skeletal muscle
Locomotion, manipulation of environment and facial expression
function of smooth muscle
propels substances through hollow organs
function of cardiac muscle
propels blood
Involuntary muscles
cardiac and smooth
what is the most common tupe of tissue in the body
skeletal muscle
How many nuclei in skeletal muscle
20 or more
Excitability/Irritability
ability to respond to a stimulus
q
contractibility
forcefully shorten
extensibility
strech beyond resting length
Elasticity
recoil back to original resting length
Conductivity
cells can propagate action potentials
Epimysium
fibrous connective tissue surrounding skeletal muscle
Perimysium
surrounds muscle fasicles
fascicles
bundles of muscle cells
Endomysium
surrounds each individual muscle ceel/ fiber
Site of aerobic respiration in skeletal muscles
mitochondria
Organelle responsible for muscle contraction
Myofibril
Sarcoplasmic reticulm
net that surrounds muscle fibers,
Sarcoplasmic reticulum function
Controls calcium levels by storing and releasing
T-Tubules
tubes that run around muscle fibers by the sarcoplasmic reticulum
T-tubules function
allow for rapid transmission of “action potentials”
name of the muscles cytoplasm
sarcoplasm
What are myofibrils composed of
two kinds of myo fillaments
what are the two types of myo filaments
Myosin and Actin
Which is thicker, myosin or Actin
Myosin
Myo filament that looks like a string pearls
Actin
Myofillament that looks like a tree trunk with barnacles
Myosin
Basic functional unit of skeletel muscle
Sacromere
Sacromere
Section of a muscle fiber seperated by Z line
Structure of Actin
of two strings of monomers wrapped around each other
Structure of Myosin
Unusual shape: one end is shaped like a long rod and the other end is double headed (like…a 2-headed snake OR a 2-headed golf club).
Alpha-Actinin
anchors the actin to the z line on bothe ends
Troponin-tropomyosin function
prevents myosin-actin bonding during relaxation and facilitates bonding during contraction
how does a sarcomere contract
when the heads of the myosin filament pull on the 2 actin filaments
why does a myo fibril contract
simultaneous contraction of sarcomeres in a myofibril
why does a muscle fiber contract
Because all sacromeeres in all myofibrils contract simultaneously
how quickley is ATP depleted
6 seconds (once vigorours activity starts)
Jpw dpes ADP interacte with creatine phosphate
anerobicly
creatine phosphate
high energy compound stored in muscles
How quickly does ADP react with creatine
almsot instaentaneously
how long can creatine phosphate and ADP sustain maximum muscle power
10-15
Glycolysis
the initial pathway of glucose respiration, forms 2 pryuciv acid and a small amount of ATP
when there is an oxygen shortage, what happens to the pyruvic acid
it is converted into lactic acid (less efficient byt faster)
how long does anaerobic respiration provide ATP
30-40 minutes
what produces most of the ATP
respiration
Aerobic Respiration
Whem muscles are actively contracting, glucose becomes the primary fuel source.
where does aerobic respiration occur
the mitochondria
what does Aerobic respiration require
oxygen
results of aerobic respiration
glucose is broken down completley, resulting in large amounts of Atp
activities associated with anerobic repiration
tennis and soccer
activities associated with aerobic repiration
jogging and marathon runs
how many places are muscles attached to bone usually
two
insertion
the moveable bone
the origin
the immovable or less moveable bone
how do muscles create movement
pulling (nevr pushing)
what are skeletal muscles controlled by
a neuron
where are neurons located
Neroumascular junction
Synaptic cleft
gap between terminal end of the neuron and the muscle
what initaties muscle movement
nerve impulse
action potential
wave of depolarization along the nerve membrane
motor endplate
point where the nuron’s axon is attached to the muscle fiber
what happens when the wave of depolarization reaches the motor endplate
the membrane of the axons synaptic knob release acetylcholine into
acetylcholine
neurotransmiter across neuromuscular junction
why cant myosin interact with actin in resting muscle
the myosin heads are covered with tropinin
what happens when tropanin binds with calcium
they change shape and are repositioned to not interfere with the myosin and actin
