Chapter 10 - Muscular Tissue Flashcards
(3) types of muscular tissue
skeletal
cardiac
smooth
skeletal muscle
moves?
striated?
voluntary/involuntary?
moves bones
striated
works in voluntary manner but also controlled **subconsciously **
**Cardiac **Muscle
found where?
striated?
voluntary/involuntary action?
found **only **in walls of the heart
striated
involuntary
**Smooth **Muscle
located?
striated?
involuntary/voluntary action?
located in **walls of hollow internal structure **(blood vessels, airways & many organs)
lacks striations
usually involuntary
Functions of **Muscular Tissue **(4)
1) producing body movements
2) stabilizing body positions
3) moving substances within body
4) generating heat
Properties of Muscular Tissue (4)
1) electrical excitability
2) contractibility
3) extensibility (stretch)
4) Elasticity (can return to normal length)
Skeletal Muscle Tissue
connective tissue components
Fascia
Epimysium
Perimysium
Endomysium
Fascia
Dense sheet or broad band of irregular connective tissue that surrounds muscles
(3) layers of connective tissue extend from fascia to protect & strengthen skeletal muscle
1) Epimysium
2) Perimysium
3) Endomysium
1) Epimysium
The outermost layer of dense irregular connective tissue
circles entire muscle
2) Perimysium
Separates 10-100 muscle fibers into bundles called fascicles
3) Endomysium
penetrates interior of each fasicle & seperates individual muscle fibers from one another (mostly reticular fibers)
Tendon
cord that attached muscle to a bone
Aponeurosis
connective tissue elements extend as broad flat sheet
(broad flattened tendon)
Neurons that stimulate skeletal muscle to contract are ____________motor neurons
The axon of a somatic motor neuron typically ____________many times, with each ___ extending to a different skeletal muscle fiber
somatic
branches
branch
The ____________of skeletal muscle fibers is set before you are born
(most of these cells last a lifetime)
number
Muscle growth occurs by?
**muscular hypertrophy **- an enlargement of existing muscle fibers
What can stimulate hypertrophy?
**Testosterone **& **Human Growth Hormone **
what cells retain the capacity to regenerate damaged muscle fibers ?
satellite cells
The plasma membrane of a muscle cell
sarcolemma
Tiny invaginations of sarcolemma
Tunnel in from the plasma membrane
Muscle action potentials travel through
Transverse (T Tubules)
the cytoplasm of a muscle fiber
includes glycogen used for synthesis of ATP and a red-colored protein called ____ which binds oxygen molecules
Sarcoplasm
Myoglobin
**Myoglobin **& oxygen?
protein that binds oxygen and releases it when it is needed for ATP production
Thread like structures within the sarcoplasm which have a contractile function
myofibrils
membranous sacs which encircles each myofibril
Sarcoplasmic reticulum
dilated end sacs that butt against T-tubules from both sides
Stores calcium ions (Ca++)
& releases to trigger muscle contraction
terminal cisterns of
Sacoplasmic Reticulum
**(myo)filaments **
smaller protein structures within myofibrils that function in the contractile process
**thin **and thick
(2 **thin **for every thick)
compartments of arranged filaments
basic functional unit of a myofibril
Sarcomeres
(extend from one Z disc to another)
Narrow plate-shaped region of dense protein material
Separate one sarcomere from the next
Z discs
Thick and thin filaments overlap one another but the extent of overlap depends on?
whether muscle is contracted, relaxed or stretched
Darker middle part of sarcomere that extends entire length of thick filaments & includes parts of thin filaments that overlap thick filaments
A band
Zone of Overlap
toward each end of A band where thin & thick filaments lie side by side
lighter, less dense area of sarcomere that contains **thin **but no thick filaments
Z discs passes through center of each
I band
center of each A band which contains **thick **but no thin filaments
H zone
M line
supporting proteins that hold thick filaments together in H zone
Myofibrils are built from (3) kinds of proteins
1) contractile
2) regulatory
3) structural
Contractile proteins (2)
1) Myosin
2) Actin
Myosin
thick filaments
Functions as a motor protein (can achieve motion)
Convert ATP to energy of motion
Projections of each myosin molecule protrude outward (myosin head)
Actin
Thin filaments
**actin molecules **provide a site where a myosin head can attach
Myosin
head vs tail.
head - shaped like 2 golf clubs & protrude outward towards thin filaments
**tail - **point toward M line in center of sarcomere
Other parts of thin filaments other than actin
Tropomyosin and troponin are also part of the thin filament
In relaxed muscle
Myosin is blocked from binding to **actin. **Why?
How do can muscle contractions occur?
**WHY? - ** because trands of tropomyosin cover the myosin-binding sites (held in place by troponin)
Calcium ion binding to troponin moves tropomyosin away from myosin- binding sites
Allows muscle contraction to begin as myosin binds to actin
Structural Proteins (2)
1) Titin
2) Dystrophin
1) Titin
stabilize position of myosin
accounts for much of the elasticity & extensibilituy of myofibrils
2) Dystrophin
links thin filaments to sarcolemma
Sliding Filament Mechanism
myosin heads attach to and “walk” along thin filaments at both ends of sarcomere
**pulling thin filaments toward center of sarcomere **
Z discs come closer together & sarcomere shortens leading to shortening of entire muscle
** Length–Tension Relationship **
___ of muscle contraction depends on __ of ___
forcefulness of muscle contraction depends on length of sarcomeres
When muscle fiber is stretched,
what happens to **overlap **and **tension (forcefulness) **?
LESS overlap between thick & thin filaments
tension is diminished
When a muscle fiber is shortened,
what happens to filaments and tension?
filaments are compressed (thick filaments crumple as they are compressed against Z discs)
fewer myosin heads make contact with thin filaments
**tension **is diminished
Neuromuscular Junction
synapse between a somatic motor neuron & a skeletal muscle fiber
Where communication occurs between a somatic motor neuron and a muscle fiber
synapse
Gap that separates the two cells
synaptic cleft
Chemical released by the initial cell communicating with the second cell
neurotransmitters
sacs suspended within the synaptic end bulb containing molecules of the neurotransmitter ______
Synaptic Vesicles
contain** acetylcholine (Ach) **
The region of the muscle cell membrane opposite the synaptic end bulbs that contains Acetylcholine receptors
Motor End Plate
The tension or force of muscle cell contraction varies and is dependant on (4)
1) The rate at which nerve impulses arrive (impulses/sec) - frequency of stimulation
2) The amount of stretch before contraction
3) The nutrient and oxygen availability
4) The size of the **motor unit **
Motor Units consists of a __ ___ and the __ __ it stimulates
motor neuron
muscle fibers
The axon of a motor neuron branches out forming __ ___ with different muscular fibers (about 150)
neuromuscular junctions
Control of precise movements consist of **many small motor units **
How many muscle fibers per motor unit for:
1) voice production muscles
2) muscle controlling eye movement
3) muscles in arm & leg
1) 2-3
2) 10-20
3) 2000-3000
The total ____________of a contraction depends on the size of the motor units and the **number that are activated **
strength
A small amount of ____________in the muscle due to weak contractions of motor units
Small groups of motor units are alternatively active and inactive in a constantly shifting pattern to sustain muscle ____________ to keep skeletal muscle firm
tautness (tension)
tone
(2) types of contractions
1) isotonic
2) isometric
**Isotonic **Contraction
tension developed remains constant while the muscle changes its length
Used for body movements and for moving objects
*ie. Picking a book up off a table *
Isometric Contraction
The tension generated is not enough for the object to be moved and the muscle does not change its length
tension **increases **without a change in muscle length
Holding a book steady using an outstretched arm
(2) types of isotonic contraction
1) concentric
2) eccentric
**concentric **isotonic contraction
tension generated is great enough to overcome resistance of object to be moved, muscle **shortens **& pulls on another structure to produce movement & to reduce angle at a joint
**eccentric **muscle contraction
length of muscle **increases **
Muscle fibers vary in their content of ___
**myoglobin **- red-coloured protein that binds oxygen in muscle fibers
Red Muscle Fibers
skeletal muscle fibers that have a **high myoglobin content **
- appear darker (dark meat in chicken legs & thighs)
contain **more mitochondria **
supplied by more blood capillaries
White Muscles Fibers
Have a low myoglobin content
Appear lighter (white meat in chicken breasts)
Muscle fibers contract at different speeds, and vary in how quickly they fatigue.
Muscle fibers are classified into (3) main types based on structural & functional characteristics.
1) Slow oxidative (SO) fibers
2) **Fast oxidative-glycolytic (FOG) **fibers
3) Fast glycolytic **(FG) **fibers
1) Slow oxidative (SO) fibers
diameter size?
power?
appearance?
generate ATP by?
speed of contraction?
time until fatigue?
for what activities?
smallest
least powerful
dark red (more myoglobin)
mainly aerobic cellular respiration
slow contraction speed (last 100-200 msec)
very resistant to fatigue
capable of prolonged, sustained contractions for many hours
adapted for **maintaining posture, aerobic, endurance-type **activities (running marathons)
2) Fast oxidative-glycolytic (FOG) fibers
diameter?
contains? appearance?
generates ATP by?
resistance to fatigue?
speed of contraction?
contribute to which activities?
**intermediate **diameter size
lots of myoglobin & many **blood capillaries **
**aerobic cellular respiration **but also anaerobic glycolysis
moderately high resistance to fatigue
**faster **contraction speed ( < 100 msec)
walking & sprinting
3)** Fast glycolytic (FG) **fibers
diameter?
strength?
contains? appearance?
generates ATP by?
resistance to fatigue?
adapted for?
**largest **
most powerful contractions
low **myoglobin, fewbloodcapillaries&mitochondria**
white in colour
mainly by **glycolysis **
fibers contract strongly & quickly
fatigue quickly
intense anaerobic movements of short duration (weight lifting)
Most muscles are a mixture of all 3 types of muscle fibers
Proportions vary, depending on ….(3)
1) action of the muscle
2) the person ’s training regimen
3) genetic factors
Postural muscles of the neck, back, and legs have a high proportion of ____________fibers
slow-oxidative (SO)
Muscles of the shoulders and arms have a high proportion of ____________fibers
**Fast-Glycolytic (FG) **
Leg muscles have large numbers of both ____________and ____________fibers
**Slow-Oxidative (SO) **and **Fast Oxidative-Glycolytic (FOG) **
Various types of exercises can induce changes in muscle fibers
1) ____________exercise transforms some FG fibers into FOG fibers (does not increase muscle mass)
1) endurance
Exercises that require short bursts of strength produce an increase in the size of ___ fibers
**Fast Glycolytic **(FG)
1) Individuals with a higher proportion of FG fibers excel in ____________activity ( 2 examples)
2) Individuals with higher percentages of SO fibers excel in ____________activities (2 examples)
**1) intense **activity (weight lifting, sprinting)
**2) endurance **activity (long-distance running)
Muscle enlargement (hypertrophy) due to increased…
synthesis of thick and thin filaments
Cardiac Muscle Tissue is the principal tissue in the ___ wall
**heart **wall
**Cardiac **Muscle Tissue
what connects the ends of cardiac muscle fibers to one another?
intercalated discs
Cardiac Muscle fibers have the same arrangedment of actin & myosin & same bands, zones & Z discs as skeletal muscle fibers but **intercalated discs **are unique to cardiac muscle fibers.
These discs contain (2)
1) **desmosomes **- hold fibers together
2) **gap junctions - **allow muscle action potentials to spread from one cardiac muscle fiber to anotehr
Cardiac muscle tissue contracts when stimulated by its own ____________muscle fibers
autorhythmic
major physiological difference between cardiac and skeletal muscle tissue
continuous, rhythmic activity
Contractions of cardiac muscle last ___ than a skeletal muscle twitch
longer
Cardiac muscle depends on _____ to generate ATP
aerobic respiration
many mitochondria
requires constant supply of oxygen
Smooth Muscle Tissue
usually activated ___
Action potentials are spread through the fibers by ____________junctions
Fibers are stimulated by certain ___ , __, or ___ signals
involuntarily
**gap **junctions
neurotransmitter, hormone or autorhythmic signals
**Smooth Muscle Tissue **
is found in the walls of? (4)
& muscles that attach/adjust? (3)
walls of arteries, veins, hollow organs, airways to lungs
muscles that attach to hair follicles, adjust pupil diameter & adjust focus on lens in eye
**Smooth Muscle **contains …? arrangement?
both **thick **and **thin filaments **
not arranged in sarcomeres
no regular pattern of overlap (not striated)
contains only **small amount of stored Ca2+ **
In Smooth muscle fibers, thin filaments attach to?
**dense bodies **& stretch from one dense body to another
**Dense bodies **of smooth muscle tissue
function?
function in same way as Z discs
during contraction, filaments pull on **dense bodies **causing shorting of muscle fiber
Contraction of smooth muscle lasts ____________than skeletal muscle contraction
initiated by? from?
longer (starts more slowly)
initiated by **Ca2+ **flow primarily from interstitial fluid & SR
Ca2+ moves slowly out of muscle fiber delaying relaxation
Smooth Muscle
Able to sustain long-term muscle tone because?
Prolonged presence of Ca++ in the cell provides for a state of continued partial contraction
Smooth Muscle is imporant in (2)?
Gastrointestinal tract where a steady pressure is maintained on contents of the tract
In walls of blood vessels which maintain a steady pressure on blood
Most smooth muscle fibers contract or relax in response to? (4)
1) action potentials from autonomic nervous sytem
2) in response to stretching
3) hormones
4) changes in pH, oxygen & CO2 levels
Muscles of the body are derived from ____________
**mesoderm **except muscles of iris & arrector pili
As the mesoderm develops it becomes arranged in dense columns on either side of the developing spinal cord
These columns undergo?
segmentation into a series of cube-shaped structures (somites)
The cells of a **somite **differentiate into (3) regions
1) myotome
2) dermatome
3) scleratome
1) myotome
2) dermatome
3) scleratome
1) Forms skeletal muscles of head, neck, and **limbs **
2) Forms the connective tissues, including dermis of skin
3) gives rise to the vertebrae
Cardiac muscle and smooth muscle develop from migrating mesoderm cells that migrate to & envelop developing ___
**cardiac muscle- **migrate to & envelop developing **heart while it is still in the form of endocardial heart tubes **
**smooth muscle - **migrate to & envelop developing gastrointestinal tract & viscera
the attachment of a tendon to the stationary bone
origin
the attachment of the muscle’s other tendon to the movable bone
insertion
the main movements of a muscle that occur during contraction
actions
** rigid structure (1)** that can move around a fixed point (2)
1) lever
2) fulcrum
A lever is acted on at two different points by **(2) different forces: **
1) **effort - **causes movement
2) **load **or **resistance **- opposes movement
1) force due to muscular contraction
2) weight that is moved
1) effort (E)
2) load or resistance
Motion occurs when?
the effort applied to bone at insertion exceeds load.
** (3) types of levers** that differ on the positions of the fulcrum, effort, and load
first-class levers - fulcrum between effort & load
**second-class levers - load **between fulcrum & effort
third-class levers - ****effort **between fulcrum & load
origin
attachement to stationary end of muscle
belly (body)
thickerm middle region of muscle
insertion
attachement to mobile end of muscle
All muscle fibers are parallel to one another within a single fascicle.
However, fascicles form **patterns **with respect to tendons (5)
1) parallel
2) fusiform
3) circular
4) triangular
5) pennate
thick in middle and tapered at ends
**(biceps brachii) **
fusiform
parallel fascicles
**(rectus abdominis) **
parallel
broad at origin and tapering to a narrower insertion
triangular
fascicles insert obliquely on a tendon
multipennate
fascicles arranged:
1) only on 1 side of tendon
2) both sides of centrally positioned tendon
1) unipennate
2) bipennate
ring around body opening
circular
**prime mover (agonist) **
produces most of force
contracts & causes action
syngergists
aid **prime mover **(located close)
stabilizes nearby joint to prevent unwanted movement
antagonist
opposes prime mover
preventing excessive movement & injury
fixator
stabilize origin of **prime mover **
prevents movement of bone
It is common to attribute a specific action at a joint to a single muscle bundle, but muscles do not work in _____________
Movements usually result from several skeletal muscles acting as a group. Most skeletal muscles are arranged in _____________ (antagonistic) pairs at joints
In an opposing muscle pair, one is called the prime mover or agonist and is responsible for the action, while the other muscle called the _____________ stretches and yields to effects of the agonist
To prevent unwanted _____________ at other joints or to otherwise aid the movement of the agonist, muscles called _____________ contract and stabilize the intermediate joints.
Other muscles act as _____________ , stabilizing the origin of the agonist so that the agonist is more efficiently
isolation
opposing
antagonist
movement
synergists
fixators
Muscles of facial expression
located?
originate? insert?
lie within subcutaneous layer
originate in fascia or skull bones
insert into skin
Because of their insertions, the muscles of facial expression move the ____________rather than a ____________when they contract.
**skin **rather than a joint
Facial expression muscles innervated by?
facial (VII) nerve (CN VII)
(6) extrinsic eye muscles control movements of each eyeball.
(originate on outside of eyeballs in bony orbit & insert on outer surface of sclera)
superior recti
inferior recti
lateral recti
medial recti
superior oblique
inferior oblique
superior rectus
moves eye **superiorly & medially **(elevation & adduction)
rotates eye medially
inferior rectus
moves eye inferiorly (depression) & medially (adduction) & rotates medially
lateral & medial rectus
move eye laterally (abduction) & medially (adduction)
inferior oblique
elevation & abduction & rotates laterally
superior oblique
depression, abduction & rotates medially
Recti muscles of the eye have obvious actions.
The actions of the (2) oblique eye muscles can’t be deduced from their names.
origin & insertion of oblique eye muscles
1) superior oblique
origin: sphenoid, superior & medial to tendinous ring in orbit
**insertion: **between superior & lateral recti (via tendon that passes through trochlea)
2) inferior oblique
**origin: **maxilla in floor of orbit
**insertion: **between inferior & lateral recti
levator palpebrae superioris
origin, insertion, action
does not move eyeball
origin: roof of orbit
**insertion: **skin of upper eyelids
**actions: **elevates upper eyelid (opens eyes)
Muscles of the tongue
(2) types
1) **intrinsic **- alter shape of tongue
2) extrinsic -move tongue, connect tongue to hyoid, styloid process, palate & inside of chin
(4) extrinsic muscles of the tongue
genioglossus - down & forward
styloglossus - up & backward
Hyoglossus - down & flattens
Palatoglossus - raises posterior portio
**Muscles of Mastication (4) **
Masseter - close mouth
Temporalis - elevate & retract
Medial Pterygoid - elevate, protrude, side to side
Lateral Pterygoid - protract, depress (open), side to side
**Muscles of Mastication **
arise from?
insert on?
arise from **temporomandibular joint (TMJ) **insert on **mandible **
Temporalis and Masseter _________ the mandible
Medial and Lateral Pterygoids help elevate, but produce ________ swinging of jaw
close
side to side
The ____________, ____________, and medial ____________account for the strength of the bite.
The medial and lateral ____________muscles help to chew by moving the mandible from side to side. Additionally, these muscles protract (protrude) the mandible.
Masseter, Temporalis & medial pterygoid
pterygoid
swallowing & speech
(2) main muscle groups in the anterior neck
**1) suprahyoid **- superior to hyoid
**2) infrahyoid **- inferior to hyoid
Both Suprahyoid & Infrahyoid muscles ___ the hyoid bone, allowing it to serve as a firm base on which the __can move.
stabilize
tongue
**Muscles of the neck that move the head **
e head articulates with the vertebral column at joints formed by the ____________& ____________bone.
atlas & occipital
An important landmark (the ____________muscle) divides the sides of the neck into two major triangles: anterior and posterior
Sternocleidomastoid
Muscles of the neck that move the head (5)
sternocleidomastoid
semispinalis capitis
splenius capitis
longissimus capitis
spinalis capitis
**Muscles of the Abdomen (protect the viscera and move the vertebral column) **
The ____________abdominal wall includes the external oblique, internal oblique, and ____________abdominis muscles which form 3 protective layers around the abdomen
anterolateral
transversus
The aponeuroses of the external & internal oblique & transversus abdominis form the ____________ which enclose the?
rectus sheaths
rectus abdominis muscles
the rectus sheaths form the ___ ___
linea alba
a connective tissue band extending from the xiphoid process to the pubic symphysis
Muscles of the Thorax that Assist in Breathing (3)
1) diaphragm
2) external intercostals
3) internal intercostals
most important respiratory muscle
diaphragm
Muscles of the Pelvic Floor (3)
Levator Ani (pubococcygeus & iliococcygeus)
Ischiococcygeus
the levator ani & ischiococcygeus together with the fascia covering their internal & external surfaces are referred to as the?
pelvic diaphragm
a diamond-shaped area inferior to the pelvic diaphragm that extends from the pubic symphysis anteriorly, to the coccyx posteriorly, and to the ischial tuberosities laterally.
perineum
(2) layers of perineal muscles
1) deep
2) superficial
superficial perineal muscles (3)
superficial transverse perineal
bulbospongiosus
ischiocavernosus
Deep muscles of perineum (5)
deep transverse perineal
external anal sphincter
compressor urethrae
sphincter urethrovaginalis
external anal sphincter
deep muscles of the perineum assist in ?
urination and ejaculation in males and urination and compression of the vagina in females
Muscles of the Thorax that Move the Pectoral Girdle
(2) groups
1) anterior thoracic muscles
2) posterior thoracic muscles
1) anterior thoracic muscles
subclavius
pectoralis minor
serratus anterior
2) posterior thoracic muscles (4)
trapezius
levator scapulae
rhomboid major
rhomboid minor
Axial muscles that move humerus (2)
pectoralis major
latissimus dorsi
scapular muscles that move humerus (7)
deltoid
subscapularis
supraspinatus
infraspinatus
teres major
teres minor
corachobrachialis
7 of 9 muscles that cross shoulder joint originate on the scapula except…
this is why they are called axial muscles
latissimus dorsi & pectoralis major
(4) deep muscles of shoulder form the **rotator cuff **
subscapularis
supraspinatus
infraspinatus
teres minor
forearm flexors
biceps brachii
brachialis
brachioradialis
forearm extensors (2)
triceps brachii
anconeus
forearm pronators
pronator teres
pronator quadratus
forearm supinator
supinator
Muscles of forearm (move wrist, hand thumb & digits)
(2) groups (2 in each)
anterior (flexor) - superior & deep
posterior (extensor) - superior & deep
superficial anterior (flexor) compartment
flexor carpi radialis
palmaris longus
flexor carpi ulnaris
flexor digitorum superficialis
deep anterior (flexor) compartment
flexor pollicis longus
flexor digitorum profundus
superficial posterior (extensor) compartment
extensor carpi radialis long
extensor carpi radialis brevis
extensor digitorum
extensor digitorum minimi
extensor carpi ulnaris
deep posterior (extensor) compartment
abductor pollicis longus
extensor pollicis longus
extensor pollicis brevis
extensor indicis
Intrinsic muscles of the hand (palm) (move digits)
(3) groups
thenar (lateral)
hypothenar (medial)
intermediate (midpalmar)
thenar eminance formed by?
thenar muscles + adductor pollicis
thenar (lateral aspect of palm) muscles
abductor pollicis brevis
opponens pollicis
flexor pollicis brevis
adductor pollicis
hypothenar (medial aspect of palm) muscles
abductor digiti minimi
flexor digiti minimi brevis
opponens digiti minimi
intermediate (midpalmar)
lumbricals
palmar interossei
dorsal interossei
Muscles of the Neck and Back that Move the Vertebral Column
Splenius
Erector spinae (iliocostal, longissimus, spinalis)
transversospinales
segmental
scalenes
Erector spinae group
3 columns muscle
from sacrum to ribs extends vertebral column
Semispinalis group
vertebrae to vertebrae
extends neck
Multifidis
vertebrae to vertebrae
rotates vertebral column
quadratus lumborum
ilium to 12th rib
lateral flexion
muscles of the back (4)
erector spinae group
semispinalis group
multifidis
quadratus lumborum
muscles of the gluteal region that move the femur
iliopsoas (psoas major & iliacus)
gluteus maximus, medius & minimus
tensor fascia latae
piriformis
obturator internus & externus
superior & inferior gemellus
quadratus femoris
adductor longus, brevis & magnus
pectineus
Muscles of the thigh
(3) compartments
1) medial (adduction)
2) anterior (extensor)
3) posterior (flexor) - flex & extend thigh
Muscles of the leg that move the foot & toes
(3) compartments
1) anterior - dorsiflex foot
2) lateral (fibular) - plantar flex & evert
3) posterior (superior & deep)
Intrinsic muscles of the foot that move the toes
(2) groups
1) dorsal
2) plantar
There is only ____________dorsal muscle which extends toes 2–5 at the MTP joints.
2
Plantar muscles are arranged in __layers with the most superficial of these called the first layer, etc.
4
