lecture 3 muscle Flashcards
muscles pull on bones to move the animal through space
locomotion
muscles move the jaw as part of oral processing of food
mastication
three type of muscle
skeletal
smooth
cardiac
describe skeletal muscle
attached to bone, moves skeleton
locomotion, respiration, generates heat by shivering
multinucleated somatic innervation (voluntary)
describe smooth muscle
GI tract and other organs, skin and most vessels
- moved ingesta, gland products and blood
Describe Cardiac Muscle
heart and great vessels
pumps arterial blood striated branched cells innervated by ANS (involuntary) Purkinje fibers corrdinate heartbeat
the force a muscle produces is related to the number of ___ active
muscle fibers
more active fibers = more force
muscles can only ___
pull
skeletal muscle cells are made up of bundle of ___
myofibrils
myofibrils are made of ___ and ___ in units called ____
thin (actin)
thick (myosin)
sarcomeres
when muscle contract ___ and ___ get closer together
myosin and actin
types of muscle fatigue
slow fatigue resistance
fast fatigue resistant
fast fatigue
(fast intermediate
example of slow fatigue resistant
migratory bird
slow contraction
- weak forces
- high resistance to fatigue
- maintain activity for long periods
- high oxidative enzyme, low glycoltic and ATPase
explain fast fatigue resistant
antelope running
fast contraction
force maintained over time
animal active for long periods
high oxidative and glycolytic capacity
explain fast fatigue
cheetah running
fast contraction
large forces, few contractions then needs rest
- high glycolytic activity and ATPase, low oxidative capacity
describe fast intermediate
catch all
- fast contraction but can maintain (some but not all) for an extended period
- fatigue resistance- varies between species
three type of contraction of muscle
concentric
eccentric
isometric
describe concentric contraction
shortens
load < muscle capacity
(bicep curl)
describe eccentric contraction
actively lengthens
load > capacity
- resists but lengthens
(lowering patient gently to floor)
describe isometric contraction
length remains constant
-angle unchanged
(carrying heavy box)
describe passive stretch
antagonist muscle working will pull (lengthen other muscle)
touch your toes
type of muscle fibers arrangments
strap
fusiform
pennate
circular
strap muscles
parallel fibers
fusiform muscles
converge at ends
(football shaped)
biceps
pennate muscles
fibers lie at angle to muscle axis
= more strength
unipennate- one tendon
bipennate- 2 tendons
multipennate- multiple internal tendons
___ cross section is perpendicular to muscle axis
anatomical
muscle axis (line from one end of muscle to the other- connects the two ends)
___ cross section is perpendicular to muscle fibers
physiologic
increasing the cross section between anatomical and physiologic will ___ force
angle between muscle axis and muscle fibers
increase force= bigger angle
muscle fibers are surrounded by ___
endomysium
groups of muscles are called ___ and are surrounded by ____
fascicles (fasciculi)
perimysium
whole muscle is surrounded by ___
epimysium
connective tissue of muscles from outside to inside
epimysium (around whole muscle)
perimysium (around fascicle)
endomysium (around muscle fiber)
narrow cordlike connection between muscles and bones
tendon
flat sheet like connection of muscles
aponeurosis
connection of muscle attachments where the connective tissue can not be seen by the naked eye
fleshy attachment
end of muscle that is more fixed or proximal
origin
end of muscle that is more mobile or more distal
insertion
tendons heal slowly because
they are poorly vascularized
motor unit
motor axon to muscle fibers
5-2000 muscle fibers per motor unit
sensory innervation of muscles
stretch receptors, tendon organs, pain receptors (in muscle and tendons)
___ help prevent friction and wear when pressure is applied from one side
bursa
outside of joint capsule (its own thing)
muscle and other tissue- bursa are not found bone to bone
when pressure is applied to more than one side (bone below and CT above ___ are formed
tendon sheaths
- form around tendons
- has little hole to allow innervation (mesotendon)
- example (retinaculum (CT) then tendon wrapped in tendon sheath then bone)
hole in tendon sheath to allow innervation and blood supply
mesotendon
skeleton is a system of ___ and levers. Muscles act on it to produce ____
supports
movement
___ support is support without muscular effort
static support
connective tissue (stay mechanism)
first order lever
head and spine
seasaw
head resistance down, fulcrum (spine in middle) muscle pulls down to keep head elevated
fulcrum between ends. resistance at one end. input force applied at other end of lever
second order levers
calcaneus and gastrocnemius
fulcrum (foot)
resistance from weight of animal pulls down
gastrocnemius pulls up
fulcrum at one end
force applied to other end
load is between input force and fulcrum
third order lever
elbow and bicep
resistance of weight of arm pulls down
- muscle pulls up (force)
- fulcrum (elbow)
fulcrum at one end
load is at other end
force applied between load and fulcrum
in 1st order levers
longer input levers =
more power to move load
output/input <1
(1st order fulcrum in between load and resistance)
in 1st order levers
longer output lever=____
longer output lever= load moves farther/time
output/input > 1
armadillo
lower output/input ration =
slower but more powerful motion of paw (digging)
kangaroo higher output/input ratio =
faster but less powerful motion of foot (hopping)
muscle that contracts to cause a motion
agonist/ prime mover
muscle that resists the motion of the agonist
antagonist
- muscles move opposite
biceps and triceps (one relaxed one active)
if antagonist muscles both contract the joint is ___
stabilized in fix position
muscle that helps move a joint
helper muscle (synergist)
biceps and brachialis
muscle fibers can shorten to ___ of their resting length
1/3
stretch or tear ligaments
sprains
bruise deep tissue without tearing the skin
contusions
inflammation/irritation of tendon of tendon sheath
tendinitis
inflammation of bursa
bursistis
mild injuries damage ___ % of muscle fibers and have ___ recovers
5
quick
Moderate injuries damage ___ muscle fibers and take ___ to heal
most
months
