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