Week 10- Skeletal Muscle Movement & Anatomy Flashcards
what are the 3 types of muscle?
1) cardiac
2) skeletal
3) smooth
is cardiac muscle voluntary or involuntary and where would it be located?
involuntary
located in heart
is smooth muscle voluntary or involutary and where would it be located?
involuntary
- intestines
- blood vessels
- bladder
- eye
- uterus etc.
is skeletal muscle voluntary or involuntary and where would they be located?
voluntary
- attached to bones
- produce body movements
- posture
- generates heat
different groups of what determine the type of movement produced?
1) muscles
2) bones
3) joints
what are the 4 major factors that determine the type of muscle produced?
1) orientaton of the muscle
2) action of other muscles
3) type of joint
4) muscle tension
what is the orientation of the muscle and how does it help determine the movement produced?
where muscle originates and inserts
(the origin and insertion)
- depending on which bone the muscle is attached to and where it inserts on determines the movement
ex: biceps
origin = scapula
insertion = radius
what is the action of other muscles and how does it determine the type of movement produced?
- when there’s more than 1 muscle attached to bone
when different muscles that insert on the same bone across the same joint contract at the same time, a completely different movement is produced than if one contracts and the other doesn’t
what does not work in isolation?
muscles
movements usually result from what?
several skeletal muscles acting as a group
(antagonistic pairs)
- prime move/ agonist vs. antagonist
how does the type of joint determing the type of movement produced?
movement also regulated by number and arrangement of ligaments across joints
the shorter the ligament, the shorter the movement
(not as flexible)
how does muce tension determine the type of movement produced?
how much a mucle is stretched determines how much movement is produced
- there is a limit to how much a muscle can be stretched
ex: touching your hands to toes, people with tighter hamstring muscles are more resricted than others.
what are the 7 common characteristics used to name muscles?
1) direction of muscle fibres
2) size of muscle
3) shape of muscle
4) number of origins
5) specific location of muscle
6) points of origin & insertion
7) action
what is an example of naming a muscle based on direction of muscle fibres?
rectus abdominus:
rectus = “erect” / straight
abdominus = abdomen
what is an example of naming a muscle based on the size?
lattissimus dorsi
lattissimus = wide
dorsi = on back
= wide muscle on back
what is an example of naming a muscle based on its shape?
deltoid:
shape = triangular
what is an example of naming a muscle based on the location?
gluteus maximus
gluteus = buttock (in greek)
maximus = largest
= big butt muscle
what is an example of naming a muscle based on the action?
adductor longus:
adductor = adducts leg (going towards midline)
longus = long muscle
= long muscle adducts leg
what is an exampe of naming a mucle based on number of origins?
biceps brachii:
biceps = 2 points of origin
brachii = arm (in latin)
= arm with 2 pointd of origin
what are the 16 basic types of movement?
1) flexion / extension
2) abduction / adduction
3) rotation
4) circumduction
5) elevation / depression
6) planter flexion / dorsiflexion
7) inversion / eversion
8) supination / pronation
9) protraction / retraction
what is abduction vs. adduction?
abduction = away from midline
adduction = towards midline
what is the difference of rotation and circumduction?
rotation = promixal and distal end of bone moves
circumduction = distal end of bone moves in circular motion
what is the difference of flexion and extension?
flexion: decrease in joint angle
extension: increase in joint angle
what is the difference of supination and pronation?
supination: palm of had moves upwards
pronation: palm of hand moves downwards
- can also be used to determine different parts of body being moved
what is the difference of eversion and inversion?
eversion: foot moves away from midline
inversion: foot moves towards midline
**only used with feet**
what is the difference of plantarflexion and dorsiflexion?
plantarflexion: foot extends at ankle (ballerina)
- toes points away from body
dorsiflexion: foot flexes at ankle
- toes point towards body
what is the difference of protraction and retraction?
protraction: bone moves horizontally towards the front
retraction: bone moves horizontally towards the back
what is the difference of elevation and depression?
elevation: bone moves upwards
depression: bone moves downwards
what are ligaments?
bands of fibre that hold articulating bones together
what are tendons?
tough bands of fibrous connective tissue that connect muscle to bone
what are bursae?
pockets of synovial fluid that cushions areas where tendons and ligaments rub together
what is muscle tone?
partial contraction of skeletal muscle
what is paralysis?
loss/ impairment of motor function
- due to damage/interference of nerves or muscle
what is muscle atrophy?
decrease of muscle size
- lack of muscle activity reduces size, tone and power
what is muscular hypertrophy?
excessive increase in muscle fibre size
- increase diameter of muscle fibres
- increases mitochondria and glycogen reserves
what is muscular dystrophy?
group of inherited muscle-destroying diseases
what are the 3 levels of muscle organization?
1) Fascia
2) Fascicles
3) muscle fibres
what is the arrangment of muscle cells in skeletal muscles starting from the outside?
1) fascia
2) epimysium
3) perimysium
4) fascicle
5) endomysium
6) muscle fibres
what forms the tendon?
1) fascia
2) epimysium
3) perimysium
4) endomysium
** extends past muscles to form tendon**
what is fascia?
outside membrane of skeletal muscle
what is epimysium?
another membrane under fascia that holds together fascicles
- fibrous connective tisssue
what is a fascicle?
group of muscle fibres that are arranged in bundles
what is the perimysium?
fibrous membrane that surrounds fascicles
what is the endomysium?
connective tissue layer that surrounds each idvidual muscle fibre
whu does each muscle cell have its own nerve?
due to skeletal muscles being voluntary
- in the endomysium
what is the structure of an individual muscle fibre?
- long
- 1 muscle cell runs through whole length of bone
- multiple nucleus
why are skeletal muscles multi nucleate?
the myoblasts fuse together to form the muscle cell, each with their own nuclei
what is the advantage of having multiple nuclei?
control events locally rather than 1 nucleus controlling the whole muscle due to skeletal muscles being long
what is the structure of an individual muscle fibre?
1) sarcolemma
2) Transverse tubules
3) sarcoplasmic reticulum
4) sarcoplasm
5) myofilaments
6) myofibrils
7) many nuclei
8) mitochondria
what is sarcolemma?
cell membrane in the muscle cells that the cell is surrounded by
what is sarcoplasm?
the cytoplasm of the cell
what are transverse tubules?
tube like structures that extend into the cell between sarcoplasmic reticulum and myofibrils
- part of the sacrolemma
AKA the dents in the sacrolemma
what is the sacroplasmic reticulum?
surrounds the myofibrils
what are myofibrils?
structures responsible for muscle contraction
what are myofilaments?
the protein that myofibrils are made of
why is it important to have a lot of mitochondria?
needs tons in order to produce tons of ATP
what are the 3 kinds of protein that structure the myofibril?
1) contractile
2) regulatory
3) structural
what is the contractile proteins and fuction?
- actin
- myosin
generate the contraction force
what are the regulatory proteins and function?
- troponin
- tropomyosin
helps to start and stop contractions
what are the structural proteins and function?
- z-line
- m-line
- titan filament
keep contractile proteins aligned and stabilize the myofibril
what are the structures of a sacromere?
1) z-line
2) I band
3) A band
4) H zone
5) M line
why do we have striations when looking at a skeletal muscle?
due to the particular arangement of the myofibril proteins
what part of the myofilament is actin?
thin filaments
what part of myofilament is M-line?
middle line that holds myosin in place
what part of the myofilament is myosin?
thick filaments
what part of the myofilament is the Z-line?
part that holds actin in place
what is the titan filament?
coiled protein strand that is attached to both Z & M line
coils when muscle contracts
uncoils when muscle relaxes
what is the H-zone?
zone where only myosin is active
what is I band?
zone where only actin is present
what is A band?
zone where myosin and actin overlap
what happens to each zone when muscle contracts?
- ends get closer together when muscle contracts
- Actin and myosin do NOT get shorter as muscle contracts
- H (myosin only) and I (actin only) zone dissapear when muscles contract
what is the structure of a myosin molecule?
rod like tail
2 globular heads
what is the ultrastructure of thin filaments?
- mostly composed of actin
- spiral formation
- subunits contain active site that mysoin heads attach to
- Tropomyosin and troponin are regulatory subunits bound to actin
what lies on top of actin?
tropomyosin
prevents myosin and actin from binding
