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Chapter 11
1. How do skeletal muscles produce body movements by pulling on bones? (Hint:
Use the terms origin, insertion, and belly in your explanation.)
Ans: pg. 340 – the insertion end of the muscle pulls the belly of the muscle
toward the origin end of the muscle
2. When you flex your knee, where are the fulcrum and load?
Ans: pg. 340 – fulcrum: knee joint; load: weight of the lower leg
3. A soccer player kicks a soccer ball down the field, flexing his thigh forward at the
hip joint while keeping his knee locked in extension. What is the lever? The
fulcrum? The effort? The load?
Ans: pg. 340 – a) leg; b) hip joint; c) thigh muscle; d) leg
4. Two girls sit down on a playground seesaw, or teeter-totter. Both children weigh
the same amount. Maria sits at the end of her side of the seesaw while Tonya sits
halfway between the end and the fulcrum. Which girl will exert more force and
be lowered to the ground?
Ans: pg. 340 – Maria
5. Would a narrow, long muscle likely have a large range of motion or a highly
forceful contraction?
Ans: pg. 340 – large range of motion
6. Using Figure 11.2, give an example of a muscle named for each of the following
characteristics: direction of fibers, shape, action, size, origin and insertion,
location, and number of tendons of origin.
Ans: pg. 346, 347 – direction of fibers: rectus abdominis; shape: trapezoid; action:
depressor anguli oris; size: gluteus maximus; origin and insertion:
sternocleidomastoid; location: brachioradialis; number of tendons of origin:
biceps brachii
7. Why do the muscles of facial expression move the skin rather than a joint?
Ans: pg. 348 – they insert into skin or other muscles
8. Which muscles of facial expression would you use to blow up a balloon? To
squint? To pucker your lips? To frown?
Ans: pg. 350, 351 – a) buccinator; b) orbicularis oculi; c) orbicularis oris; d)
risorius
9. Which extrinsic eye muscles contract as you gaze to your left without moving
your head? Which relax?
Ans: pg. 352 – a) lateral rectus; b) medial rectus
10. Which extrinsic eye muscles cause elevation of the anterior eyeball?
Ans: pg. 352 – superior rectus
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11. What would happen if an injury resulted in loss of nerve stimulation (innervation)
to your masseter and temporalis muscles?
Ans: pg. 355 – mouth could not close
12. What are the functions of your tongue?
Ans: pg. 355 – aids in mastication, taste perception, deglutition and speech
13. When your physician says, “Open your mouth, stick out your tongue and say ahh”
so she can examine the inside of your mouth for possible signs of infection, which
muscles do you contract?
Ans: pg. 356 – genioglossus
14. What is the combined action of the suprahyoid and infrahyoid muscles?
Ans: pg. 358 – stabilize the hyoid bone
15. What should happen to the hyoid bone when the suprahyoid muscles contract?
When the infrahyoid muscles contract?
Ans: pg. 359 – a) elevate; b) depress (lower)
16. Which muscles do you contract to signify “yes”? Which do you contract to
signify “no”?
Ans: pg. 361 – a) semispinalis capitis; b) sternocleidomastoid
17. State the direction of the fascicles for the external oblique, internal oblique,
transverses abdominis, and rectus abdominis muscles?
Ans: pg. 363, 364 – external oblique: inferiorly and medially; internal oblique:
extend at right angles to those of external oblique; transverses abdominis:
transversely around the abdominal wall; rectus abdominis: down the entire length
of the anterior abdominal wall
18. Which abdominal muscle aids in urination?
Ans: pg. 363 – rectus abdominis
19. Which muscles do you contract when you “suck in your tummy,” thereby
compressing the anterior abdominal wall? Which do you contract when you
rotate the vertebral column?
Ans: pg. 363 – a) rectus abdominis, external oblique, internal oblique, transverses
abdominis; b) internal oblique, external oblique
20. Which muscles do you contract to increase the dimension of your thoracic cavity
during quiet, normal inhalation?
Ans: pg. 364 – diaphragm and external intercostals
21. Name the structures that pass through the diaphragm.
Ans: pg. 364 – aorta, esophagus, inferior vena cava
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22. What are the borders of the pelvic diaphragm?
Ans: pg. 368 – pubis (anteriorly), coccyx (posteriorly), one lateral wall of the
pelvis to the other
23. Which muscles help expel urine and semen? Which maintain erection of the
penis and clitoris?
Ans: pg. 370 – a) deep transverse perineal, external urethral sphincter, external
anal sphincter; b) superficial transverse perineal, bulbospongiosus,
ischiocavernosus
24. What are the borders of the perineum?
Ans: pg. 370 – from the pubic symphysis anteriorly, to the coccyx posteriorly , to
the ischial tuberosities laterally
25. What is contained within the borders of the urogenital triangle and the anal
triangle?
Ans: pg. 371 - urogenital triangle: external genitals; anal triangle: anus
25. Name the muscles that are used to raise your shoulders and those that are used to
lower your shoulders.
Ans: pg. 374 - raise: trapezius and levator scapulae; lower: pectoralis minor,
subclavius
26. Name the muscles that flex, extend, and adduct your arm at the shoulder joint.
Ans: pg. 377 – flex: deltoid (anterior fibers), coracobrachialis; extend: latissimus
minor; adduct: pectoralis major, latissimus dorsi, infraspinatus, teres major, teres
minor, coracobrachialis
27. The tendons of which muscles make up the rotator cuff?
Ans: pg. 376 – subscapularis, supraspinatus, infraspinatus, teres minor
28. Flex your arm at the elbow joint. Which muscles are contracting? Which
muscles must relax so that you can flex your arm?
Ans: pg. 377 – a) biceps brachii, brachialis, brachioradialis; b) triceps brachii,
anconeus
29. Name the muscles that supinate and pronate your forearm.
Ans: pg. 379 – supinate: supinator, biceps brachii, brachoradialis; pronate:
pronator teres, pronator quadratus, brachioradialis
30. Extend your hand at the wrist. Which muscles are contracting? Which muscles
must relax so that you can extend your hand?
Ans: pg. 382 – a) extensor carpi radialis longus, extensor carpi radialis brevis,
extensor digitorum, extensor carpi ulnaris; b) flexor carpi radialis, palmaris longus,
flexor carpi ulnaris, flexor digitorum superficialis, flexor digitorum profundus
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31. State the functions of the flexor retinaculum and extensor retinaculum.
Ans: pg. 383 – flexor retinaculum: secures the tendons of the flexors of the
fingers and wrist; extensor retinaculum: stabilizes tendons of the extensors of the
wrist and fingers
32. Which extrinsic and intrinsic muscles of the hand are used to flex the thumb? To
abduct the thumb?
Ans: pg. 386 – a) flexor pollicis brevis; b) abductor pollicis brevis
33. Name the extrinsic and intrinsic muscles of the hand that flex the fingers and
those that are used to adduct the fingers.
Ans: pg. 386 – flex: abductor digiti minimi, flexor digiti minimi brevis,
lumbricals: adduct: palmar interossei
34. Which muscle groups constitute the erector spinae?
Ans: pg. 390 – iliocostalis, longissimus, and spinalis
35. Name the muscle groups that laterally flex the head and those that laterally flex
the vertebral column.
Ans: pg. 390, 391 – laterally flex the head: spenius capitis, splenius cervicis,
anterior scalene, middle scalene, posterior scalene; laterally flex vertebral column:
iliocostalis cervicis, longissimus thoracis, multifidus, intertransversarii
36. What are the principal differences between the muscles of the upper and lower
limbs?
Ans: pg. 393 – upper limb muscles are characterized by versatility of movement;
lower limb muscles are larger and more powerful to provide stability, locomotion,
and maintenance of posture, they also often cross two joints and act equally on
both
37. Which busy muscles flex, adduct, and medially rotate the femur at the hip joint?
Ans: pg. 394 – adductor longus, adductor brevis, adductor magnus
38. Which muscles extend the leg at the knee joint?
Ans: pg. 397 – quadriceps femoris (rectus femoris, vastus lateralis, vastus
medialis, vastus intermedius)
39. Name the muscles that are part of the iliopsoas, quadriceps femoris, and
hamstrings. Where is each muscle group found?
Ans: pg. 396 397 – iliopsoas: psoas major and iliacus; quadriceps femoris: rectus
femoris, vastus lateralis, vastus medialis, vastus intermedius: hamstrings: biceps
femoris, semitendinosus, semimembranosus
40. Which busy muscle flexes, abducts, and laterally rotates the thigh at the hip joint
and flexes the leg at the knee joint?
Ans: pg. 398 - sartorius
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41. Which muscle tendons form the medial and lateral borders of the popliteal fossa?
Ans: pg. 397 – tendons of the biceps femoris muscles (laterally) and tendons of
the semitendinosus and semimembranosus muscles (medially)
42. Name the muscles that dorsiflex the foot at the ankle joint and those that plantar
flex it?
Ans: pg. 399 – dorsiflex: extensor hallucis longus and extensor digitorum longus;
plantar flex: fibularis longus and fibularis brevis
43. Which muscles flex the toes? Which extend the toes?
Ans: pg. 403 – a) flexor digitorum longus, flexor hallucis longus; b) extensor
digitorum longus, extensor hallucis longus
44. How do the intrinsic muscles of the hand and foot differ in function?
Ans: pg. 404 – muscles of the hand are specialized for precise and intricate
movements; muscles of the foot move the toes and contribute to the longitudinal
arch of the foot
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