Muscles Part 2 Bio 120 A&P1

Name the three groups of muscles constituting the intrinsic muscles of the hand. Briefly describe the structure and function of each of these groups.

1. Thenar: four muscles that act on the thumb and form the lateral rounded contour of the palm. 2. Hypothenar: three muscles that act on the little finger and form the medial rounded contour of the palm. 3. Intermediate: 12 muscles acting on all digits except the thumb; subgrouped as lumbricals, palmar interossei, and dorsal interossei, and located between metacarpals; needed for all phalangeal movements

With reference to the effort and load, describe the main difference between a lever operating with a mechanical advantage versus a lever operating at a mechanical disadvantage.

A lever operates at a mechanical advantage when a smaller effort can move a heavier load. The effort moves a greater distance at a faster rate than the load. A lever operates at a mechanical disadvantage when a larger effort moves a lighter load. The effort moves more slowly and for a shorter distance than the load. When the load is far from the fulcrum and the effort is applied near the fulcrum, the effort applied must be greater than the load to be moved. This type of leverage is mechanically advantageous because it allows the load to be moved rapidly through a large distance, with only minimal muscle shortening.

The knee (tibiofemoral) joint can be described by what statements? Select all that apply. a) The force is applied between the fulcrum and the resistance. b) The resistance is between the fulcrum and the force. c) The fulcrum is between the force and resistance. d) Produces a mechanical disadvantage. e) Produces a mechanical advantage. f) first-class lever g) second-class lever h) third-class lever

Answer 1: a Answer 2: d Answer 3: h

Briefly describe the three categories of levers based on the position of their fulcrum. Give an example of each type of lever and state whether the lever works at a mechanical advantage, disadvantage or both

If the fulcrum is between the effort and the load it is a first class lever. Scissors are an example of a first class lever. A first class lever can produce either a mechanical advantage or disadvantage depending on whether the effort or load is closer to the fulcrum. If the load is between the fulcrum and the effort, it is a second class lever. A wheel barrow is an example of a second class lever. They operate at a mechanical advantage because the load is always closer to the fulcrum than the effort. If the effort is between the fulcrum and the load, it is a third class lever. Forceps are an example of a third class lever. They operate at a mechanical disadvantage because the effort is always closer to the fulcrum than the load.

Briefly describe four main benefits of stretching before exercising.

Stretching can improve physical performance by increasing joint flexibility allowing the joint to move through a greater range of motion. Stretching decreases risk of injury by decreasing resistance in various soft tissues so there is less of a chance of exceeding maximum tissue extensibility during activity. Stretching can reduce some of the muscle soreness that results after exercise. Stretching can help realign soft tissues to improve and maintain good posture.

Discuss the roles of agonists, antagonists, synergists, and fixators in movement.

The agonist (prime mover) contracts to cause a particular movement. The antagonist causes the opposite action, and so, must relax while the agonist contracts. Synergists prevent unwanted movements during an action or aid the agonist during the movement, while fixators stabilize the origin of the agonist. Both allow the agonist to work more efficiently.

What anatomical structures of the musculoskeletal system correspond to the components of a lever system? Describe the arrangement of these parts in first, second, and third class lever systems.

The bone is the lever. The joint is the fulcrum. The muscle contraction pulling on its insertion point is the effort. The weight of the part to be moved is the resistance. A first class lever has the fulcrum between the effort and the resistance; a second class lever has the resistance in the middle; the third class lever has the effort in the middle. In all cases, the lever moves around the fulcrum.

Name and describe the locations and actions of the muscles typically used in breathing

The diaphragm forms the floor of the thoracic cavity. It flattens (contracts) during inspiration to increase the size of the thoracic cavity. The external intercostals are found between the ribs and they act to increase the lateral and anteroposterior dimensions of the thorax. Internal intercostals are also found between ribs and they act by pulling the ribs together to decrease the size of the thoracic cavity. The diaphragm relaxes during expiration to form a dome that decreases the size of the thoracic cavity. The anterior scalenes and the pectoralis minor also assist during forced inspirations.

Chuck has a rotator cuff injury. Which muscles and associated structures are most commonly involved in this type of injury? What sorts of activities commonly cause this injury?

The tendon of the scapularis, supraspinatus, infraspinatus, and teres minor make up the rotator cuff. The most commonly injured structure of the rotator cuff is the tendon of the supraspinatus muscle. Any activity involving vigorous circumduction of shoulder can result in a rotor cuff injury. Common examples of activities that lead to this injury include throwing baseballs, playing racket sports, and swimming

The rhomboid major is named for what characteristics? Select all that apply. a) Size b) Shape c) Number of origins d) Sites of origins e) Location

a b

Which muscle's insertion fuses with the calcaneal tendon? Select all that apply. a) soleus b) gastrocnemius c) plantaris d) popliteus e) flexor hallucis longus

a b c

Your friend nods back and forth to you, making the "yes" motion. What muscles are involved in this 'yes' motion? Select all that apply. a) bilaterally sternocleidomastoid b) unilaterally sternocleidomastoid c) bilaterally semispinalis capitis d) unilaterally semispinalis capitis e) bilaterally splenius capitis f) unilaterally splenius capitis g) bilaterally longissimus capitis h) unilaterally longissimus capitis i) spinalis capitis

a c e g i

Which muscles have a triangular fascicle arrangement that spreads over a broad area and converges at a thick central tendon? Select all that apply. a) pectoralis major b) rectus femoris c) deltoid d) pectoralis minor e) lattisimus dorsi f) orbicularis oris g) digastric

a d e

During inhalation, _____muscles contract to elevate the ribs. During forced exhalation, ______muscles contract to depress the ribs. a) external intercostals; internal intercostals b) transverse abdominis; diaphragm c) diaphragm ; transverse abdominis d) internal intercostals; external intercostals e) rectus abdominis; external obliques

a) external intercostals; internal intercostals

Which muscles help move the jaw during mastication? a) masseter, temporalis, pterygoid (medial and lateral) b) genioglossus, styloglossus, hyoglossus, palatoglossus c) omohyoid, sternohyoid, thyrohyoid d) sternocleidomastoid, longissimus capitis, splenius capitis e) orbicularis oris, levator labii superioris, depressor labii inferioris

a) masseter, temporalis, pterygoid (medial and lateral)

What terms can be used to describe forearm muscle movements at the wrist but NOT on the fingers at the interphalangeal joints? a) flexion, extension, abduction, and adduction b) extension and flexion c) abduction and adduction d) flexion and adduction e) pronation and supination

abduction and adduction

The muscle that serves as the "prime mover" during a movement is called the a) antagonist. b) agonist. c) synergist. d) asynergist. e) fixator.

agonist

If one is stabbed on the lateral side of the abdomen, what abdominal muscles, in order from superficial to deep, will the knife go through? a) rectus abdominis, external oblique, internal oblique b) external oblique, internal oblique, transversus abdominis c) transversus abdominis, rectus abdominis, external oblique d) external oblique, transversus abdominis, rectus abdominis e) internal oblique, transversus abdominis, external oblique

b) external oblique, internal oblique, transversus abdominis

"How much wood would a woodchuck chuck if a woodchuck could chuck wood" is difficult to say. What muscles work together to allow this to be spoken? a) masseter, buccinators, temporalis, platysma b) palatoglossus, styloglossus, genioglossus, hyoglossus c) risorius, zygomaticus minor, zygomaticus major d) mentalis, orbicularis oris, levator labii superioris e) sternohyoid, omohyoid, sternothyroid

b) palatoglossus, styloglossus, genioglossus, hyoglossus

Which of these groups includes only muscles that move the humerus but do NOT originate on the axial skeleton? a) serratus anterior, latissimus dorsi, trapezius b) supraspinatus, teres major, teres minor, infraspinatus c) deltoid, brachioradialis, latissimus dorsi, pectoralis major d) trapezius, pectoralis minor, pectoralis major, triceps brachii e) triceps brachii, biceps brachii, brachioradialis

b) supraspinatus, teres major, teres minor, infraspinatus

Forcefully blowing through a trumpet would require contraction of which muscle? a) buccinator b) zygomaticus major c) levator labii superioris d) risorius e) occipitofrontalis

buccinator

Which muscles help expel urine in both males and females? Select all that apply. a) compressor urethrae b) deep transverse perineal c) external urethral sphincter d) bulbospongiosus e) superficial transverse perineal f) ischiocavernosus

c d

Tapping your fingers against the table, similar to typing on a keyboard would use what muscles? Select all that apply. a) Flexor carpi ulnaris b) Extensor carpi ulnaris c) Flexor digitorum profundus d) Flexor digitorum superficialis e) Palmaris longus f) Extensor digitorum g) Extensor digiti minimi h) Extensor pollicis brevis

c d f g

Based on its name, which of the following best describes characteristics of the biceps femoris muscle? a) has two insertions and found in lower leg b) has two bellies and found in the upper leg c) has two origins and found in the upper leg d) has two origins and found in the upper arm e) has two insertions and found in the upper leg

c) has two origins and found in the upper leg

The transvers abdominis [dropdown 1] compress the abdomen, and [dropdown 2] flex the vertebral column like other anterior abdominal muscles. Dropdown choices: can cannot

can cannot

Which fascicle arrangement, under voluntary or involuntary regulation of contraction, can control the opening or closing an orifice (opening)? a) pennate b) triangular c) circular d) parallel e) fusiform

circular

During knee flexion, what is the effort? a) knee joint b) contraction of hamstring muscle group c) weight of lower leg and foot d) femur e) tibia

contraction of hamstring

Motion will occur at a lever system when a) resistance at the insertion exceeds the load. b) the force of the contraction is not more than the load. c) effort at the origin exceeds the load. d) effort at the insertion exceeds the load

effort at the insertion exceeds the load

Your friend nods back and forth to you, making the "yes" motion. What muscle actions on the head at the neck are involved in this 'yes' motion? a) rotation and circumduction b) lateral and medial rotation c) extension and flexion d) protraction and retraction e) elevation and depression

extension and flexion

Tim ate something that is not agreeing with his digestive tract. He needs to go to the bathroom to defecate, but there is a line. What muscle helps keep the anal canal and anus closed? a) bulbospongious. b) ischiocavernosus c) obturator internus d) external anal sphincter e) sphincter urethrovaginalis

external anal sphincter

The ______ are the synergist muscles to the diaphragm during inspiration. a) external intercostals b) external obliques c) rectus abdominis d) internal intercostals e) internal obliques

external intercoastals

Your friend nods "yes" to you, going through flexion, extension and hyperextension. This movement at the fulcrum represents a a) first- class lever system b) second- class lever system c) third-class lever system d) third-class lever system

first class

Your friend nods back and forth to you, making the yes motion. What lever system is being represented by this 'yes' motion? a) First-class lever b) Second-class lever c) Third-class lever

first class lever

This type of muscle works by stabilizing the origin of the agonist so that it can act more efficiently. a) synergist b) agonist c) antagonist d) fixator e) secondary mover

fixator

) Due to the muscle attachments, a fracture to the ischial tuberosity would affect what lower limb movement? a) adduction of the thigh b) dorsiflexion of the foot c) extension of the leg d) flexion of the leg e) abduction of the thigh

flexion of the leg

A woman complains of problems going up steps. Tests reveal hip extension weakness but no issues with hip flexion or knee flexion or extension. What muscle is most likely damaged? a) Adductor magnus b) Gluteus maximus c) Gluteus medius d) Semitendinosus e) Sartorius

gluteus maximus

Protrusion of an organ through a structure that normally contains it is referred to as a a) hernia. b) goiter. c) strain. d) sprain. e) hydrocele.

hernia

Most muscles cross at least one a) tendon b) joint c) bone d) ligament e) body plane

joint

When the knee is being flexed, what is the fulcrum? a) femur b) weight of lower leg and foot c) knee joint d) tibia e) contraction of quadriceps femoris

knee joint

Robert is training for a track race. He slightly tears his calcaneal tendon. The doctors prescribe P.R.I.C.E and give him medicine for inflammation and pain. Robert most likely has a a) muscle sprain b) muscle strain c) repetitive strain injuries d) plantar fasciitis e) compartment syndrome

muscle strain

This muscle, which is found in the neck, functions to elevate the hyoid bone and help press the tongue against the roof of the mouth during swallowing. a) mylohyoid b) sternothryroid c) sternocleidomastoid d) digastric e) masseter

mylohyoid

The attachment of a muscle's tendon to the stationary bone is called the _____; the attachment of the muscle's other tendon to the movable bone is called the _____. a) origin, action b) insertion, action c) origin, insertion d) insertion, origin

origin, insertion

Which motions can be made by the upper limbs but NOT by the lower limbs? a) pronation and supination b) flexion and extension c) adduction and abduction d) lateral and medial rotation

pronation and supination

Which of these muscles flexes the thigh at the hip joint alone, but extends the knee working in a group? a) biceps femoris b) rectus femoris c) semitendinosus d) semimembranosus e) vastus lateralis

rectus femoris

Which of these muscles has fascicles parallel to the midline? a) external obliques b) transverse abdominis c) rectus femoris d) biceps femoris e) orbicularis oculi

rectus femoris

When the biceps brachii contracts, the radius is pulled closer to the muscle, while the scapula remains still. Based on this information, the biceps brachii origin is [a]and the insertion is [b]. Answer options [a] and [b] Scapula Radius Ulna Clavicle Elbow joint

scapula radius

A 1 year old child presents with crossed eyes. While she seems fine and is able to recognize people, the patient is diagnosed with a) nystagmus. b) strabismus. c) presbyopia. d) myopia. e) hypermetropia.

strabismus

Which of the following is a muscle whose insertion is found on the clavicle and acromion process of the scapula within the pectoral girdle? a) trapezius b) pectoralis major c) latissimus dorsi d) gracilus e) sartorius

trapezius