Chapter 6 Muscles
when a weak but smooth muscle contraction is desired, _____ are stimulated at a rapid rate.
few motor units
a muscle cell
fiber
muscle group of the lateral leg; plantar flex and evert the foot
fibularis muscle
inserts on the metatarsals of the foot
fibularis, tibialis anterior
Antagonist, Fixator, Prime Mover, or Synergist?? immobilizes the origin of the prime mover
fixator
Antagonist, Fixator, Prime Mover, or Synergist?? postural muscles for the most part
fixator
the pectoralis major and deltoid muscles act synergistically to ______ the arm
flex
In climbing stairs, the hip and knee of the forward leg are both ______
flexed
An emergency appendectomy is performed on Carlos. The incision was made at the lateral edge of the right iliac abdominopelvic region. What muscles needed to be cut? What will be the affect? What movement shall be limited for a while?
The internal and external obliques must be cut. Movements that will be limited are rotation and flexion of the spine.
you have just touched you chin to your chest; this is ______ of the neck
flexion
in running, the action at the hip joint is ______ in reference to the leg moving forward and ______ in reference to the leg in the posterior position
flexion; extension
wrist flexor that follows the ulna
flexor carpi ulnaris
muscle that flexes the fingers
flexor digitorum superficialis
the extrinsic muscles of the hand originate on the ______
forearm
originates from the cranial aponeurosis
frontalis
"toe dancer's" muscle; a two- bellied muscle of the calf
gastrocnemius
inserts on the calcaneus via the achilles tendon
gastrocnemius
primary muscle in the calf: _____
gastrocnemius
_____ _______ is the primary muscle of the buttocks
gluteus maximus
used to extend the hip when climbing the stairs
gluteus maximus
named for the relative size of the muscle
gluteus maximus, adductor magnus
named for the location of the muscle relative to a bone or body region
gluteus maximus, biceps femoris, abdominis transversus, extensor carpi ulnaris, rectus femoris, and external oblique
smaller hip muscle commonly used as an injection site
gluteus medius
muscle group that extends the thigh and flexes the knee
hamstrings
the muscle group in the back of the thigh: ______
hamstrings
originates on the hip
hamstrings, adductors, illopsoas, glutes
hip flexor, deep in pelvis; a composite of two muscles
iliopsoas
besides the rectus abdominis and external oblique, name two muscle pairs that help form the natural abdominal girdle
internal oblique and transversus abdominis
______ is the ability for a muscle to respond to stimulation
irritability
A(n) ______is a contraction in which the muscle does not shorten but tension in the muscle keeps increasing
isometric contraction
A(n) ______ is a contraction in which the muscle shortens and work is done
isotonic contraction
large paired superficial muscle of the lower back
latissimus dorsi
muscle that adducts the shoulder and causes extension of the shoulder joint
latissimus dorsi
synergist to the trapezius muscle: _______
latissimus dorsi
which region of the sarcomere shortens during contraction- dark band, light band, or both
light band
to accomplish a strong contraction, ____ are stimulate at a rapid rate
many motor units
Gregor, who works at a pesticide factory, comes to the clinic complaining of muscle spasms that interfere with movement and breathing. A blood test shows that he has been contaminated with organophosphate pesticide, which is an acetylcholinesterase inhibitor. How would you explain to Gregor what this means?
The pesticide is a chemical that inhibits the enzyme ACh. ACh remains in the synapse and stimulates muscle activity.
Mrs. Sanchez says that her 6- year- old son seems to be usually clumsy and tires easily. The doctor notices that his calf muscles appear to be normal in size. If anything, they seem a bit enlarged rather than wasted. For what condition must the boy be checked? What is the prognosis?
The possibly has Duchenne muscular dystrophy. The condition could be fatal if it impairs respiratory muscles.
An emergency appendectomy is performed on Mr. Geiger. The incision was made at the lateral edge of the right iliac abdominopelvic region. Was his ractus abdominus cut?
The rectus abdominus is narrow and medially placed muscle that doesn't extend completely across iliac regions. That incision described does not cut the rectus abdominus
extension
movement that increases the angle between two bones
abduction
moving a limb away from the midline
adduction
moving a limb towards the midline
a long, filamentous organelle found within muscle cells that has a banded appearance
myofibril
actin- or myosin- containing structure
myofilament
______ are the thick microfilaments (A bands)
myosin
Susan, a massage therapist, was giving Mr. Graves a backrub. What two broad superficial muscles of the back were receiving the "bulk" of her attention?
Trapezius and latissimus dorsi
Depressor anguli oris
*Not in textbook* PM: depresses corner of mouth O: Tubercle of mandible I: Modiolus of mouth
Describe the contraction mechanism in a skeletal muscle cell
Achetylcholine (ACh) is released into the neuromuscular junction by the axonal terminal. ACh diffuses across the neuromuscular junction and binds to receptors on the sarcolemma. Depolarization occurs, and the action potential is generated. The action potential, carried deep into the cell, causes the sarcoplasmic reticulum to release calcium ions. The calcium ion concentration at the myofilaments increases; the myofilaments slide past one another, and the cell shortens. As calcium is actively reabsorbed into the sarcomplasmic reticulum, its concentration at the myofilaments decreases. The muscle cell relaxes and lengthens.
People with chronic back pain occasionally get relief from a tummy tuck. How does this help? What muscles could be impacted from obtaining this procedure?
By reducing the size of the abdomen, the abdominal contents are forced into a smaller space which would increase the intra-abdominal pressure. The rise in intra-abdominal pressure would force the vertebrae to move further apart, reducing vertebral compression and pressure oon the nerve fibers that transmit pain. The rectus abdominus and the external obliques are possibly affected during this procedure.
What specific muscles receive injections when a patient needs them?
Deltoid, gluteus medius, and vastus lateralus (part of quads group)
Sally was painting her house and fell off the ladder. She fractured her right clavicle. Treatment prescribed by the ER doctor included a sling for her right arm to immobilize the clavicle and speed its healing. What muscles are temporarily "put out of business" by the sling? What can Sally do to heal herself?
Deltoid, pectoralis major/ minor, trapezius, biceps, and triceps are temporarily "put out of business". Sally should keep her arm in a sling to keep it immobilized, ice and take pain killers to reduce pain and inflammation.
During an overambitious workout, a high school athlete pulls some muscles by forcing his knee into extension when his hip is already fully flexed. What muscles does he pull?
Hamstrings can be pulled when the hip is flexed and the knee is vigorously extended at the same time.
What is the difference between isometric and isotonic contraction? In addition, classify each of the following activities as either isometric or isotonic: a) bicep curls b) balancing on your tip toes c) tug of war d) sit- ups e) pushing against the wall
Isometric- muscle doesn't shorten but tension increases sustained contraction. isotonic- movement; muscle shortens/ contracts and changes length. a. bicep curls is isotonic b. balancing on your tip toes is isometric c. tug of war is isometric when deadlocked d. sit ups are isotonic e. pushing against the wall is isometric
circumduction
a combination of flexion, adduction, extension, and abduction
motor unit
a motor neuron and all of the skeletal muscle cells it stimulates
named for the direction in which the muscle fibers run relative to some imaginary line
abdominis transversus, rectus femoris, external oblique
raising the arms laterally away from the body is called ______ of the arms
abduction
___ are the thin microfilaments ( I bands)
actin
named for the action of the muscle
adductor magnus, extensor carpi ulnaris
muscle group that allows you to draw you legs to the midline of your body, as when standing at attention
adductors
Almost as soon as the depolarization wave begins, a repolarization wave follows it across the membrane. This occurs as _______.
K+ diffuses out of the cell
Antagonist, Fixator, Prime Mover, or Synergist?? reverses and/ or opposes the action of a prime mover
antagonist
muscle that allows you to bend (flex) the elbow
biceps brachii
named for the number of origins
biceps femoris
How is muscle contraction mechanical, chemical, and electrical in nature?
Mechanical: filaments slide (A and I bands) A bands- thick- myosin I bands- thin- actin Chemical- neurotransmitters, ACh, sodium- potassium pump, calcium in sarcoplasmic reticulum Electrical- nerve impulse- nerves send signal to contract
When the stimulus is delivered, the permeability of the membrane is changed, and ________, initiating the depolarization of the membrane
Na+ diffuses into the cell
deltoid
PM: Abducts arm (humerus) O: scapular spine and clavicle I: Humerus (deltoid tuberosity)
Quadriceps group (vastus, medualis, intermedius, and lateralis; and the rectus femaris)
PM: All extend the knee; rectus femaris also flexes hip on thigh O:vasti- femur Rectus femoris- pelvis I: tibial tuberosity via patellar ligament
Orbicularis Oculi
PM: Blinks and closes eyes O: Frontal bone and maxilla I: Tissues around eyes
Tibialis Anterior
PM: Dorsiflexes and inverts foot O: Proximal tibia I: first cuneiform (tarsal) and first metatarsal of foot
Flexor carpi ulnaris
PM: Flexes wrist and adducts hand O: distal humerus and posterior ulna I: carpals of wrist and fifth metacarpal
Zygomaticus
PM: Raises corner of mouth O: Zygomatic bone I: skin and muscle at corner of lips
Frontalis
PM: Raises eyebrows O: cranial aponeurosis I: skin of eyebrows
gluteus medius
PM: abducts thigh; steadies pelvis during walking O: ilium I: proximal femur
Adducter muscles
PM: adduct thigh O: pelvis I: proximal femur
Pectoralis Major
PM: adducts and flexes humerus O: Sternum, clavicle, and first to sixth ribs I: Proximal Humerus
Orbicularis oris
PM: closed and protrudes lips O: Mandible I: skin and muscle around mouth
Temporalis
PM: closes jaw O: Temporal bone I: mandible
Masseter
PM: closes jaw O: temporal bone I: mandible
Buccinater
PM: compresses cheek as in whistling and sucking; holds food between teeth during chewing O: Maxilla and mandible near molars I: orbicularis oris
Transversus abdominis
PM: compression abdomen O: Iliac crest, inguinal ligament, thoracolumbar fascia, and costal cartilages 7-12 I: Xiphoid process, linea alba, pubic crest and pecten pubis via conjoint tendon
Latissumus dorsi
PM: extends and adducts humerus O: lower spine and iliac crest I: proximal humerus
Erector Spinae
PM: extends back O: iliac crests, ribs 3-12, and vertebrae I: Ribs, thoracic and cervical vertebrae
Triceps Brachii
PM: extends elbow O: shoulder girdle and proximal humerus I: olecranon process of ulna
extensor digitorum
PM: extends fingers and wrist O: distal humerus I: distal phalanges of second and fifth fingers
gluteus maximus
PM: extends hip (when forceful extension is required) O: sacrum and ilium I: Proximal (gluteal tuberosity)
Trapezius
PM: extends neck and adducts scapula O: occipital bone and all clavicular and thoracic vertebrae I: scapular spine and clavicle
Extensor digitorum longus
PM: extends toes and dorsiflexes foot O: Proximal tibia and radius I: distal toes 2-5
extensor carpi radialis
PM: extends wrist and abducts hand O: humerus I: base of second and third metacarpals
Hamstring muscles (semitendinosus, semimembranosus, biceps femoris)
PM: flex knee and extend hip O: ischial tuberosity I: proximal tibia (head of fibula in the case of biceps femoris)
External oblique
PM: flexes and rotates vertebral column O: lower eight ribs I: iliac crest
Brachialis
PM: flexes elbow O: distal humerus I: proximal ulna
Biceps Branchii
PM: flexes elbow and supinates forearm O: scapula of shoulder girdle I: proximal radius
Iliopsoas
PM: flexes hip O: ilium and lumbar vertebrae I: femur (lesser trochanter)
Sternocleidomastoid
PM: flexes neck; rotates head O: Sternum and clavicle I: temporal bone (mastoid process)
Sartorius
PM: flexes thigh on hip O: ilium I: proximal tibia
Rectus abdominis
PM: flexes vertebral column O: pubis I: sternum and fifth to seventh ribs
Flexor carpi radialis
PM: flexes wrist and abducts hand O: distal humerus I: second and third metacarpals
flexor digitorum superficialis
PM: flexes wrist and fingers O: distal humerus, ulna and radius I: middle phalanges of second and fifth fingers
Fibularis muscles
PM: plantar flex and evert foot O: fibula I: metatarsals of foot
soleus
PM: plantar flexes foot O: proximal tibia and fibula I: calcaneus
gastrocnemius
PM: plantar flexes foot and flexes knee O: distal femur I: calcaneus (heel via calcaneal tendon)
Platysma
PM: pulls corners of mouth inferiority O: connects tissue covering of superior chest muscles I: tissue around mouth
Internal oblique
PM: vertebral flexion, rotation, compression O: Inguinal ligament, iliac crest, and the lunbodorsal fascia I: Linea alba, Pecten Pubis (via Conjoint tendon) and ribs 10-12
Muscles working together in the lower extremity
Primary Mover: Quadriceps Synergist: sartorius Antagonist: hamstrings Fixator: iliapsoas
muscles working together in the upper extremity
Primary mover: Biceps Antagonist: Triceps Synergist: brachioradialis and brachialis Fixator: deltoid
runs from the distal humerus to the proximal ulna; flexes the elbow
brachialis
the triceps surae insert in common into the ______ tendon
calcaneal
muscle type that coordinated activity to act as a pump
cardiac
muscle type that has a figure- 8 packaging of the cells
cardiac
muscle type that is banded in appearance
cardiac and skeletal
Muscle type that is involuntary
cardiac and smooth
winding up for a pitch can properly be called _____. To keep your seat when riding a horse, the tendency is to ______ your thighs.
circumduction; adduct
During oxygen debt.....
decreased ATP, increased lactic acid, decreased oxygen, increased carbon dioxide
flexion
decreases the angle of a joint and brings two bones closer together
originate on the scapular spine and clavicle
deltoid
powerful shoulder adductor, used to raise the arm overhead
deltoid
prime mover for shoulder abduction
deltoid
shoulder muscle that is the antagonist of the latissimus dorsi
deltoid
the muscle of the shoulder cap is the ______
deltoid
binding of the neurotransmitters with muscle membrane receptors causes the membrane to become permeable to sodium, resulting in the influx of sodium ions and _______ of the membrane
depolarization
an unpaired muscle that accomplishes inspiration
diaphragm
Sam was advised by his physician to lose weight and start jogging. He began to jog daily. On the sixth day he was forced to jump out of the way of a speeding car. He heard a snapping sound that was immediately followed by pain in his right lower calf. A gap was visible between his swollen calf and his heel, and he was unable to plantar flex that foot. What do you think happened? What should be done to alleviate his discomfort?
Sam tore his calcaneal or achilles tendon. Wear a boot and keep foot elevated. Physical therapy and icing will also be needed.
Comparative Anatomy: Rabbit Vs. Human
Similarities: 1. Similar muscles found in similar locations. 2. 3. Differences: 1. Rabbits are digitigrade, meaning they walk on fingers and toes. This compares to to humans which are plantigrade and have the ability to walk on heels. 2. Rabbits have very muscular back legs in order to help power their hops. 3.
Why do you think skeletal muscle is multinucleated as opposed to cardiac muscle?
Skeletal muscle have multiple nuclei because they are composed of several skeletal muscles fused together, which retain their nuclei and need the length and enegy.
Would the muscles that cause flexion of the neck have their origin or their insertion on the head?
Sternocleidomastoid originates on the sternum and clavivle and inserts on the mastoid process. It flexes and turns the neck. The trapezius also flexes the neck and originates on the occipital.
Repolarization restores the ______ of the resting cell membrane
electrical conditions
out of control during a temper tantrum, Malcolm smashed his fist through a glass door. Seven tendons were sliced through the anterior wrist. What movements are likely to be lost if tendon repair is not possible?
Tendons attaching at the anterior wrist and flexion. He will lose his ability to make a fist and grasps things in his hand.
The ______ surrounds each muscle fiber
endomysium
thin connective tissue investing each muscle cell
endomysium
connective tissue ensheathing the entire muscle
epimysium
prime mover of back extension; a deep composite muscle consisting of three columns
erector spinae
inserts on thoracic and cervical vertebrae
erector spinal
when kicking a football, the action at the knee is ______
extension
named for the location of the muscle's origin and/ or insertion
extensor carpi ulnaris
inserts on distal phalanges of 2nd and 5th digits
extensor digitorum
muscle the extends the fingers
extensor digitorum
inserts on distal toes #2-5
extensor digitorum longus
deep muscles of the thorax that promote the inspiratory phase of breathing
external intercostal
originates from lower eight ribs
external oblique
part of the abdominal girdle; forms the external lateral walls of the abdomen
external oblique
What are two major antagonistic muscle groups located distally on the lower appendages? What are their primary movements, origins, and insertions?
The hamstrings and quadriceps are antagonistic muscles in the leg. The hamstrings flex the knee and extend the hip. They originate in the ischial tuberosity and insert in the proximal tibia. The quadriceps extend the knee and flex the hip. They originate on the femur and pelvis and insert on the patellar ligament.
A ______ consists of many muscle fibers
fascicle
a discrete bundle of muscle cells
fascicle
the perimysium surrounds each ______
fascicle
bundles of muscle cells are called _____
fascicles
when a muscle is being stimulated but is not able to respond due to "oxygen debt" the condition is called _______
fatigue
When the _______ reaches the ends of the axon, the neurotransmitter is released, and it diffuses to the muscle cell membrane to combine with receptors there
nerve impulse
runs from the frontal bone and inserts on the tissue around the eyes
orbicularis oculi
inserts on tissue surrounding mouth
orbicularis oris, platysma
There is a greater concentration of Na+ _____, and there is a greater concentration of K+ _______
outside the cell; inside the cell
prime mover for shoulder flexion and adduction
pectoralis major
inserts on humerus
pectoralis major, latisssimus dorsi, deltoid
connective tissue surrounding a fascicle
perimysium
standing on your toes as in ballet is _____ of the foot. Walking on your heels is _____
plantar flexion; dorsiflexion
Antagonist, Fixator, Prime Mover, or Synergist?? agonist
prime mover
action that moves the distal end of the radius across the ulna is ______
pronation
the bulk of the tissue of a muscle tends to lie ______ to the part of the body it causes to move
proximal
group of muscles that inserts on the tibia via the patellar ligament
quadriceps
muscle group that extends the knee
quadriceps
the insertion tendon of the ______ group contains a large sesamoid bone, the patella
quadriceps
the muscle group in front of the thigh is called ______
quadriceps
the name means "straight muscle of the abdomen"
rectus abdominis
originates on pubis and inserts on sternum and #5-7 ribs
rectus abdominus
The _____ are replenished by the ________
relative ionic concentrations on the two sides of the membrane during rest; activation of the sodium- potassium pump, which moves Na+ into the cell and K+ out of the cell
using a screwdriver with a straight arm requires ____ of the arm
rotation
rotation
rotation is a movement of a bone around its longitudinal axis
A ______ is the smallest functional unit of contraction
sacromere
plasma membrane of the muscle cell
sarcolemma
contractile unit of muscle
sarcomere
strap- like muscle that is weak thigh flexor; "tailors muscle"
sartorius
muscle type that is dense connective tissue packaging
skeletal
muscle type that is referred to as the muscular system
skeletal
muscle type that is voluntary
skeletal
muscle type that moves bones and facial skin
skeletal
muscle type that is longitudinally and circularly arranged in layers
smooth
inserts directly on the calcaneus
soleus
like the two- bellied muscle that lies over it, this muscle is a plantar flexor
soleus
acting alone, each muscle of this pair turns the head toward the opposite shoulder
sternocleidomastoid
runs from the sternum and clavicle to the temporal bone
sternocleidomastoid
Antagonist, Fixator, Prime Mover, or Synergist?? performs the same movement as the prime mover
synergist
Antagonist, Fixator, Prime Mover, or Synergist?? stabilizes a joint so that the prime mover can act at more distal joints
synergist
runs from the temporal bone to the mandible
temporalis
cordlike extension of connective tissue beyond the muscle, serving to attach it to the bone
tendon
the connective tissue around muscles comes together at the ends to form ______
tendons
_______ is a continuous contraction that shows no evidence of relaxation
tetanus
synaptic cleft
the actual gap between an axonal ending and the muscle cell
axonal terminal
the axon of each motor neuron has numerous endings
inverts and dorsiflexes the foot
tibialis anterior
muscle that allows you to shrug your shoulders or extend your head
trapezius
named for the shape of the muscle
trapezius
originate from occipital bone
trapezius
the muscle that contracts when you shrug your shoulder: _______
trapezius
______, _____, + _______ are the primary muscles when rowing
trapezius, deltoid, and pectoralis
antagonist muscle to the biceps: _____
triceps
originate on the shoulder girdle and proximal humerus
triceps
muscle that extends the elbow
triceps brachii
______, ______, + ________ are the primary muscles working when doing push- ups
triceps, biceps, and pectoralis
______ are the chambers that contain high concentrations of calcium
tubules
How would stimulation of smooth muscle contraction affect blood pressure, air inhalation, and defecation?
vasoconstriction leads to high blood pressure, while vasodilation leads to lower blood pressure. Smooth muscle lines the inside of vessels, so when they are contracted, blood pressure increases. Smooth muscle also lines the airway, so contraction of them may cause wheezing and coughing, as well as hacking up mucus. Smooth muscle is also in the GI tract which helps with defecation.
achetylcholine
within the axonal endings are many small vesicles containing a neurotransmitter substance
Briefly describe how you can tell when you are repaying the oxygen debt?
your rate of respiration is much faster and you breathe more deeply