110 Mt2

Front 1

4 major evolutionary transformations in the cranial skeleton

Back 1

1. jaw joint in mammals
2. middle ear of tetrapods
3. secondary palate of mammals
4. fenestration of the skull roof

Front 2

evolution of tetrapod jaw joint and middle ear are related. involve major (3 each) anatomical and functional transitions

Back 2

gills, jaws, ears
breathing, feeding, hearing.

Front 3

evolution of the mammalian jaw joint step 1: (4)

Back 3

-in tetrapod ancestors (eg sarcopterygian fish)
-amphistylic
-jaw joint between Quadrate and Articular
-hyomadibula involved in jaw suspension.

Front 4

evolution of the mammalian jaw joint step 2: (5)

Back 4

-early tetrapods, amphibians, most amniotes, including early synapsids
-secondary autostylic
-jaw joint between quadrate and articular
-hyomandibula not involved in jaw suspension
-hyomandibula: columella (involved in hearing, tympanic membrane transmitted to otic capsule, sound interpreted)

Front 5

evolution of the mammalian jaw joint step 3: (5)

Back 5

-cynodont therapsids
-secondary autostylic
-"double jaw joint": quadrate + articular, squamosal (part of temporal)+dentary.
-columella in middle ear
-dentary enlarges with new processes, postdentary bones reduced (trend)

Front 6

why have fewer number of bones in dentary?

Back 6

fewer number of bones: better biting force and chewing because fewer weak points and breaking potentials.

Front 7

why new jaw joint?

Back 7

involved in hearing: hear thru vibrations, so if chewing, can't hear. so new jaw joint to help in hearing

Front 8

evolution of the mammalian jaw joint, step 4: (6)

Back 8

- mammals
-secondary autostylic
-jaw joint: squamosal + dentary
-columella: stapes
-quadrate + articular join stapes in middle ear (as incus and malleus)
-single dentary bone

Front 9

3 parts of ear structure:

Back 9

inner ear, middle ear, outer ear

Front 10

inner ear (6)

Back 10

contains cochlea and semicircular canals
forms in otic capsule of chondrocranium.
filled with fluid
organs of hearing and balance+equilibrium
all craniates.
(fish only have this)

Front 11

middle ear (5)

Back 11

-air-filled chamber between inner ear that includes 1-3 tiny bones and tympanic membrane
-contains 1-3 ear bones (ossicles) (reptiles only have stapes, not necessarily better with 3)
-M, I, S connected by movable joint
-has connection to pharynx via eustachain tube
-only in tetrapods

Front 12

outer ear (3)

Back 12

-tympanic membrane to the outside
-well developed in mammals
-slightly developed in some reptiles and birds.

Front 13

auditory canals in mammals, birds, reptiles, snakes:

Back 13

long in mamals,
short in birds and reptiles
none in snakes

Front 14

most fish have...?

Back 14

lateral line system: sense movement of water around them, touch environment. responds to fluid
they're all canals.
feel vibrations in fluid.

Front 15

how weaker sounds on land? so what?

Back 15

sound waves in air have 1/64 the strength of sound waves in water. so tympanic membrane is sensitive to minimal energy. and hyomandibula was positioned right along the otic capsule.

Front 16

ancestral conditions that allowed the development of ear (2)

Back 16

1. sarcopterygian fish ancestor had amphistylic suspension with hyomandibula positioned between the otic region of braincase and the cheek bones near jaw joint.
2. first pharyngeal pouch (spiracular) is adjacent to the otic capsule and available to become the middle ear chamber.

Front 17

evolution of ear in amphibians, reptiles, and in birds (3)

Back 17

-first gill slit (spiracle) becomes middle ear cavity (air pocket for equalizing pressure) with columella;
-closed off by tympanic membrane on the outside;
-connected to pharynx via eustacian tube.

Front 18

ears development for sauropsids and synapids

Back 18

independently!

Front 19

evolution of the ear in mammals (8)

Back 19

-no evidence of tympanic membrane in early synapsids
-hyomandibula (stapes) is retained as a buttress between braincase and quadrate
-sound transmitted via ground vibrations to jaw (head on ground)
-derived synapsids (cynodonts): develop new bony process to support tympanic membrane called the reflected lamina of the angular (a dermal bone of lower jaw, which shrinks and becomes delicate)
-develop squamosal+dentary jaw joint; quadrate+articular become smaller and more mobile (loosely jointed)
-Dentary enlarges and takes over
-quadrate and articular removed from jaw joint and moved into middle ear (quadrate is incus, articular is malleus)
-ear becomes entirely separated from jaw joint, which is made up of squamosal and dentary bones.

Front 20

middle ear bones summary of transitions (4)

Back 20

from jaw bones:

-hyomandibula: columella: stapes
quadrate: incus
articular: malleus
angular: tympanic

Front 21

migration of ear apparatus

Back 21

from lower jaw to skull

Front 22

2 selection in hearing and feeding led to 2 results

Back 22

selection:
1. better hearing
2. greater jaw strength and chewing efficiency

result:
1. smaller ear bones
2. stronger jaw joint

Front 23

4 chain links for mammals with starting with endothermy

Back 23

1. endothermy
2. increased food requirements
3. but can only eat so fast, digest, so...? better food processing
4. stronger jaws and sharper teeth so break up food in mouth.

Front 24

primitive tetrapod condition (5)

Back 24

-primary palate
-vaulted rather than horizontal
-choanae (internal nares) open anteriorly
-retained in most living amphibians, reptiles, and birds
-4 bones: vomer, palatines, ectopterygoid, pterygoid

Front 25

secondary palate (5)

Back 25

-inward growth of marginal bones to produce bony palate below primary palate
-it separated airway from oral cavity (breathing and feeding)
-strengthens the rostrum.
-therapsid can eat and breathe at same time
-mammal: closes of oral cavity, so can breathe and eat.

Front 26

why secondary palate important? so why imp to breathe and eat at same time??

Back 26

requries you to breathe much more because higher O2 requirements.

Front 27

earliest amniotes. what species still like this?

Back 27

-had skulls without any openings in the cheek/temporal region.
-ANAPSID
-turtles
-a lot of air space
-braincase is small
-jaw muscles within the skull

Front 28

anapsid conditions gives way to...?

Back 28

skulls with 1 or 2 openings behind the orbit.

Front 29

head shapes of early amphibians (1) and early amniotes (3)?

Back 29

early amphibian: relatively flat head
early amniote: deeper head with larger jaw muscles. single opening in postorbital region.

Front 30

diapsid (6)

Back 30

-sauropsid:
-2 openings (dorsal and side)
-separated by bar made up of postorbital and squamosal.
-more room for muscles.
-very kinetic skulls in snakes sand lizard (snout can bend, protrude forward).
-snake maximize flexibility of skull.

Front 31

synapsid (2)

Back 31

one opening bordered above by postorbital and squamosal.
larger and continuous

Front 32

evolution of the synapsid skull (4)

Back 32

-single opening enlarges toward top of skull until those on each side nearly meet
-zygomatic arch (jugal and squamosal) below
-postorbital bar disappears.
-temporal openings enlarge because brain expands in size, jaw muscles enlarge and become more complex, allowing more complicated chewing movements.

Front 33

chewing muscles related to fenestration (5)

Back 33

-used to be all inside the skull
-muscles used to be attached to one thing
-more attachments on the sides going different directions
-masseter, swing jaws.
-can move from side with pterygoid muscle.

Front 34

3 general bone structures

Back 34

1. compact (cortical) vs. cancellous (spongy)
2. medullary cavity
3. periosteum

Front 35

periosteum (5)

Back 35

-membrane surrounding whole bone, tightly pressed.
-tissue lining bone with osteoblast: add cells outside of bone, enlarge in diameter.
-where muscles and tendon attach
-fibers going into bone
-shin splints because of this membrane and fibers.

Front 36

medullary cavity (2)

Back 36

-important from physiological standpoint because stores fat and produce red blood cells.
-in adults, only few places red blood cells made in hips and cranium.

Front 37

bone is living tissue and dynamic remodels throughout life to adapt to new loading patters using what two things for what?

Back 37

1. osteoclasts resorb bone that is not under stress
2. osteoblasts lay down new bone where there is stress

Front 38

compact bone (2)

Back 38

dense.
not vascular

Front 39

cancellous bone (4)

Back 39

-articular ends (joint) of bones
-made of struts called trabecula
-hydrovascular
-remodel and repair quicker than compact because more blood.

Front 40

some reasons bone can remodel? (shrink and add on? 2)

Back 40

exercise, going to space.

Front 41

ulna and radius relationship and dynamic bones

Back 41

-ulna and radius both hold up weight
-remove ulna
-all load on radius, strain is 210%
-radius changes shape because load causes it to bend.
-one side longer than the other
-after remodeled, back to 110% strain

Front 42

dog metatarsels

Back 42

-when not exercised (in a cast), osteoclasts go nuts and starts using energy for other purposes and loss of bone.
-if exercise dog, thicker and denser.

Front 43

4 important concepts for effect on bone

Back 43

force
load
stress
strain

Front 44

force

Back 44

push or pull on an object that results in motion or must be resisted to prevent motion (measured as pressure/unit area)

Front 45

load

Back 45

a general term referring to a force applied to a solid object. when a load is applied to an object (bone), it sets up an internal condition of pressure within the bone called stress.

Front 46

stress

Back 46

internal condition of an object under load (measured as load/unit area [kg/cm^2]. when an object or bone is placed under stress, a deformation or strain results.

Front 47

strain

Back 47

deformation due to a load (measured as percent change in length due to the load)

Front 48

loads can be broken down into...?

Back 48

2 components: one perpendicular and one parallel

Front 49

loads cause 4 different strains

Back 49

compression, tension, shear (offset), and torsion (turning shear)

Front 50

how do you normally break a bone?

Back 50

combination of compression, tension, and bending.

Front 51

what do you call the region in graph where big changes in stress causes only small amounts of strain?

Back 51

elastic region: if you release it, no damage and can come back.

Front 52

what do you call the region where little stress can make big strains?

Back 52

plastic region: beginning is where the load starts to break the trabecula struts. farther: bone fracture completely.

Front 53

what do you call the place inbetween the two regions?

Back 53

yield point

Front 54

what do you call the angle due to elastic region on this graph?

Back 54

Young's modulus of elasticity.

Front 55

E(modulus of elasticity) =

Back 55

stress/strain

Front 56

materials that do not deform much (like bone) are called

Back 56

"stiff" and have high values of E

Front 57

materials that deform easily (like cartilage) are called...?

Back 57

compliant and have low values of E.

Front 58

bone and cartilage with tension and compression

Back 58

bone does better with compression than tension
cartilage does WAY better with compression than tension.

Front 59

young's modulus among materials

Back 59

metal is strong
metal and bone both have elastic region with steady slope then flatten out for plastic
glass has no plastic region.

Front 60

definition of strength

Back 60

force required to break a specimen.

Front 61

monkeys

Back 61

-mammals usually strong against compression because of gravity and weight, but swinging animals are unusually strong with tension in arms from hanging off of stuff.

Front 62

bone is a composite material definition and (2) examples

Back 62

stuff made of multiple materials having different quality

inorganic component: apatite: gives bone its compressive strength (calcium, phosphorus)
organic component: collagen: gives bone its tensile strength.

Front 63

most fractures result from...? (3)

Back 63

bending, shear, or sudden impact.

Front 64

assumption of adaptations of bone

Back 64

bones have evolved to provide adequate strength with a minimum material. efficiency

Front 65

why are bones hollow? (2 ideas)

Back 65

-can argue because storing fat and blood cells
-but could be done and stored elsewhere, reason is structure

Front 66

bending creates what two important concepts on bone?

Back 66

tension and compression

Front 67

what is neutral axis?

Back 67

where no change in length of bone, not under strain.

Front 68

where should we put load to maximize strength of object or structure?

Back 68

far away from neutral axis.

Front 69

bone shape and cross-sectional geometry

Back 69

-influenced by direction of predominant stresses
-round when bending occurs in all directions
-oval when bending has a preferred direction
-greater diameter or width is oriented in the direction of expected loads
-in addition, cortical bone thickness increases where stress is greatest.

Front 70

bending strain affected by (3)

Back 70

1. bone length
2. thickness
3. cross-section shape

Front 71

name 2 axis where bending can occur

Back 71

1. mediolateral axis
2. anteroposterior axis

Front 72

strength in bending about AP axis:

Back 72

K(pi ab^3)/4

Front 73

strength in bending about ML axis:

Back 73

K (pi ba^3)/4

Front 74

if 2 materials same mass and length, what makes one stronger?

Back 74

hollow: so material farther away from neutral axis because wider.

Front 75

I-beam

Back 75

beam on 2 supports at ends causes compression on top, tension on bottom. beam on a wall is tension at top and compression on bottom.

Front 76

how are bones analogous to an I-beam?

Back 76

put material where it's needed the most

Front 77

wooden board

Back 77

maximum amount of material in line with respective load!

Front 78

cracks

Back 78

stress is concentrated in the area of a crack and so tends to propagate.

Front 79

structural adaptations of bone: crack-stoppers (2)

Back 79

1. cracks are stopped in bone by -heterogeneous composition (apatite and collagen): like fibrous collagen can stop a crack from going on, so strong against tension and crack.
2. lacunae (small spaces): made by how cortical bone grows. creates holes where they hold osteocytes, and stress is dissipated around that hole.

Front 80

structural adaptations of bone: shock absorption and stress distribution (2)

Back 80

1. presence of spongy bone at ends
2. trabecular orientation: take up load, shock absorbing. distribution by how trabecula oriented in bone, by being parallel to compressive forces, it isn't random and there is a specific way, and trabecula are remodeled in stress. struts connected to one another, connected to tiny plates, absorb shock (than compact bone). femur has stress lines (struts) aligned to get stress out to outer perimeter where bone is strongest.

Front 81

difficulty of hip replacement (5)

Back 81

-make artificial stainless steel femur with a spike and goes into bone in a new hip socket.
-new loading patterns set up
-tried to make similar to original loading pattern, but difficult because everyone is different with loading
-bone starts eroding where there is no more load and it will get loose.
-over time, replacement (10-15 years)

Front 82

joints (very general) 2

Back 82

1. vary in degree of motion allowed
2. mobile joints are synovial

Front 83

immobile joints where...?

Back 83

in skull, intervertebral joint

Front 84

synovial joint

Back 84

knee, with
1. articular cartilage on the bone
2. thick, flexible synovial membrane that forms a sac around the fluid
3. synovial fluid: secreted to lubricate the joint, minimize friction
4. articular capsule
5. meniscus: cartilagenous structural feature that divides joint cavity at distal end of femur.

Front 85

mobile joints: axes of motion or degrees of freedom (3)

Back 85

1. uniaxial: hinge joint: phalange
2. biaxial: hinge + translation: hand
3. multiaxial (3+): opposable thumb. hinge and twist around itself to touch, opposable spin around axis of thumb (so hinge, back and forth, and circular). also head and shoulder.

Front 86

function of joints (2)

Back 86

facilitate movement
shock absorption

Front 87

axial skeleton includes (4)

Back 87

1. vertebrae (notochord)
2. ribs
3. sternum (tetrapods)
4. medial fins (fish)

Front 88

functions of axial skeleton (4)

Back 88

1. protect nerve cord
2. attachment of muscles for locomotion
3. compression strut in fishes: so fish can push against dense medium (water), so don't accordion
4. suspend body weight in tetrapods

Front 89

typical amniote vertebra parts (5)

Back 89

1. neural spine: movement
2. transverse process
3 zygapophysis
4. centrum
5. vertebral foramen

Front 90

what replaces notochord?

Back 90

centrum, support, structural

Front 91

what does vertebral foramen do?

Back 91

protects nerve cord

Front 92

neural arch

Back 92

protect dorsal hollow nerve cord

Front 93

purpose of zygopophysis?

Back 93

restraining different movement. obstruction

Front 94

intervertebral disks (5)

Back 94

-separates body of vertebrae
-notochord inside (remnant)
-good shock absorber
-tough ligament inside
-vertebrae scrunch up as you age: lose thickness of intervertebral disks, get shorter

Front 95

herniated disk

Back 95

-tear of fibrous tissue
-nerves exiting
-pressing on nerves: pain
-numbing
-notochord slip out

Front 96

intervertebral foramen

Back 96

nerves come out (when 2 verbrae come together)

Front 97

5 types of centra

Back 97

1. amphicoelous
2. procoelous
3. opisthocoelus
4. acoelous
5. heterocoelous

Front 98

amphicoelous

Back 98

concave both sides, fishes some reptiles

Front 99

procoelous

Back 99

concave anteriorly, convex posteriorly (most reptiles)

Front 100

opisthocoelous

Back 100

concave posteriorly, convex anteriorly (amphibians)

Front 101

acoelous

Back 101

flat on both sides (mammals)

Front 102

heterocoelous

Back 102

saddle shaped on both ends (birds). very mobile

Front 103

what happens with bigger animal and more movement in vertebrae?

Back 103

bigger vertebrae, larger disk where more movement.

Front 104

ribs (4)

Back 104

-attach to vertebrae via synovial joints
-protect viscera
-attachment of muscles for respiration (tetrapods) and locomotion (in fish)
-calcify at sternum calficy with age

Front 105

rib development

Back 105

dorsal ribs go up and ventral ribs come down.

Front 106

fish versus tetrapods

Back 106

-tetrapods have 1 pair of articulation (with tuberculum and capitulum), positioned between myotome and coelom. can't tell if ventral or dorsal rib
-2 articulations with each vertebra: tuberculum and capitulum

Front 107

primitive condition of ribs

Back 107

ribs associated with each vertebra.

Front 108

ribs in tetrapods (2)

Back 108

-thoracic ribs meet at the sternum
-ribs of mammals and reptiles have a cartilaginous and an ossified portion.

Front 109

lung ventilation can be important but not for humans because

Back 109

we use diaphragm.

Front 110

development of vertebrae (1)

Back 110

-myotomes provide primary segregation
-sclerotome forms aggregation of mesenchymal cells around notochord and DHNC.

Front 111

centra development in amniotes (1, and 3 results)

Back 111

-sclerotomal aggregations migrate caudally to produce centra that are offset from mytomes

so result
1. myotomal muscle blocks cross two vertebrae
2. spinal nerves exit between vertebrae
3. ribs develop in septa between vertebrae

Front 112

evolution of the vertebral column (1, 2 sub-explanations)

Back 112

relative simplicity to relative complexity

increased complication of individual vertebrae - fewer parts but more processes
increased complexity along the entire column; regional differentiation (different in different parts of the body)

Front 113

fishes: trunk and caudal vertebrae (4)

Back 113

-typically, no specialized cervicals
-no zygapophyses because buoyant medium.
-heads attached to shoulder girdle to push against water, so fused for more support.
-more mobile in caudal because of locomotion.

Front 114

lamprey

Back 114

large, persistent notochord with small cartilages (arcualia) associated with it.

Front 115

primitive fishes (1 idea with 3 parts)

Back 115

-large, persistent notochord (not covered by bone or cartilage) with associated cartilages including
1. neural arch
2. dorsal and ventral arch bases
3. hemal arches on caudal vertebra

Front 116

advanced fishes (3)

Back 116

-defined centrum
-hemal arches below, not above
-protects blood flow with vessels and arteries

Front 117

chondrichthyes

Back 117

continuous, flexible cartilaginous sheath around partially calcified notochord.

Front 118

tetrapod ancestors (2)

Back 118

-large notochord
-neural arch and 3 ossifications a. pleurocentrum paired. connected by fibrous connective tissue.
b. intercentrum (surrounds notochord)

Front 119

what started appearing with first animals on land related to axial skeleton?

Back 119

zygopophysis

Front 120

early tetrapod and centrum (2 in extinct amphibians and amniotes)

Back 120

-intercentrum enlarges to become centrum in some extinct amphibians.
-pleurocentra (2 of them in pairs) enlarge and fuse to form the centrum and intercentrum disappear in amniotes

Front 121

vertebral column in water versus land (3 and 4)

Back 121

water
-stress reduced due to buoyancy
-mediolateral undulation
-head needs stiff articulation with spine

on land
-body mass loads the vertebral column (hind leg push onto socket, pressure on vertebral column)
-limb movements load the spine
-head is freed up
-transition to land selected for stronger vertebral column.

Front 122

evolution of tetrapods thru echthyostega (4)

Back 122

-large intercentrum
-zygapophyses: torsion CW and CCW, prevent vertebrae from moving too much, restraning movement.
-1 cervical vertebra: can move head up and down and that's it
-1 sacral vertebra so bony connection between leg socket and vertebral column so can push off and move. articulation to prevent 2 vertebral column from coming apart and off the back.

Front 123

fish. pectoral attached to..?

Back 123

head

Front 124

salamanders and movement

Back 124

bending and axial torsion

Front 125

turtles and special about ribs

Back 125

move ribs outside and dorsal scapula, bizarre

Front 126

early evolution of tetrapod axial skeleton (4)

Back 126

1. rib reduction
2. regional differentiation
3. more head mobility
4. more agility

Front 127

living salamanders (6) axial skeleton

Back 127

1. centra have zygapophyses with horizontal orientation: -vertebrae can move side to side with zygapophyses still on top and bottom, horizontally oriented.
2. opisthocoelous centra
3. cervical vertebra (atlas): limited mobility of head
4. trunk vertebrae bear ribs
5. sacral vertebra: single, enlarged to articulate with pelvic girdle
6. caudal vertebrae, lack zygapophyses.

Front 128

frogs, axial skeleton

Back 128

short, strong vertebral column because jumpers, totally different from salamanders. so not stretched out. no ribs, maybe cartilaginous.

Front 129

reptiles, axial skeleton

Back 129

1. cervical region: atlas and axis
2. 2-3 sacral vertebrae: because more active, bigger
3. ribs decrease in length posteriorly
4. usually procoelous vertebrae with horizontal zygapophyses

Front 130

birds (5) axial vertebrae

Back 130

-heterocoelous
-numerous cervical vertebrae (15-20): neck fancy because they have no hands. so do everything with head like grooming, etc.
-10-20 lumbar and caudal vertebrae fuse to two sacral vertebrae and pelvis to form synsacrum. compact thoracic region, a lot of loading with legs and pelvis. big single unit called synsacrum. fly, so no flex or extend because muscles are heavy, so they reduce muscles. so cement and lock up the body to save energy and drop weight.
-only 3-10 free trunk vertebrae
-6 or 7 free caudal vertebrae + pygostyle

Front 131

mammals and regional differentiation (5)

Back 131

1. usually have 7 cervical vertebrae (even giraffes)
2. usually about 20 trunk vertebrae clearly divided into Thoracis: bear ribs, and Lumbar: no ribs
3. 3 or more sacral vertebrae fuse to form a sacrum
4. caudal vertebrae
5. zygapophyses vary in orientation.

Front 132

evolution of axial skeleton in mammals (3)

Back 132

1. early synapsid: ribs all the way back
2. loss of some ribs and something happens to tail
3. first mammal: something to ribs

Front 133

evolution of mammalian craniovertebral and atlas-axis joints (6)

Back 133

-atlas - skull: biaxial rotation
-atlas - axis: uniaxial rotation
-proatlas in early synapsid limits DV movement: limited in up and down
-no zygapophysis in atlas of mammal
-rotational movement facilitated by dens
-axis and atlas move head up and down, atlas protects nerve cord.

Front 134

whales (3)

Back 134

lighter, less complex zygopophyses because no gravity, buoyant.
-put together head and neck again
-7 vertebrae converge to push against water.

Front 135

locomotion and the vertebral column: fish (what undulation?)

Back 135

mediolateral undulation.

Front 136

locomotion and the vertebral column: early tetrapods. (2)

Back 136

-limbs
-mediolateral undulation (flat back, sprawling)

Front 137

diagonal gait order and explain what it is

Back 137

RF, LH, LF, RH
-1 foot off the ground at once, triangle with other 3 to support. can't change gait, can't gallop. mediolateral undulation

Front 138

some go ______ to increase speed

Back 138

bipedal

Front 139

mammals (movement and support 3)

Back 139

-limbs move fore-aft in sagittal plane.
-feet placed under body
-dorsoventral undulation of spine (so reorientation of zygapophysis)

Front 140

thoracic versus lumbar?

Back 140

thoracic is tied, don't move as much, lumbar vertical because locomotion

Front 141

what happens to dorsoventral locomotion in really big animal?

Back 141

reduced bending.

Front 142

appendicular skeleton includes (general)

Back 142

limbs or ventral fins
pectoral and pelvic girdles

Front 143

4 sequential evolutionary steps in development of appendicular skeleton

Back 143

1. no fins, ML undulation
2. fins, ML undulation
3. 4 limbs, ML undulation: -marine reptiles: flippers. -archosaurs: bipedality and flight
4. 4 limbs, DV undulation: -marsupials, rodents, and humans: bipedality. -marine mammals: flippers.

Front 144

where did fins come from? jawless fishes.

Back 144

not really fins. some pectoral fins, but don't know where they came from.

Front 145

hypothesis on where fins came from with amphioxus.

Back 145

amphioxus had continuous fins (dorsal, splits in ventral) then they started splitting up and cutting away, and now we have fins!:
-unpaired median: dorsal (1-2 fins), caudal, and anal
-paired ventral: pectoral and pelvic

Front 146

fin function (4)

Back 146

-stabilize fish when swimming in 3D by avoiding pitch yaw, roll
-for propulsion (caudal)
-steering (pectoral)
-lift (pectoral)

Front 147

evolution of the pectoral girdle

Back 147

always has dermal and endochondral component
endochondral portion always carries the limb articulation and associates muscles.

Front 148

early gnathostomes: head and pectoral girdle

Back 148

dermal armor in head region forms a connection between the head and the pectoral fin supports.

Front 149

fin support uses what skeletal feature?

Back 149

scapulocoracoid (endochondral)

Front 150

5 dermal elements in fin support in eusthenopterion (early gnathostome)

Back 150

1. post-temporalis
2. supracleithrum
3. cleithrum
4. clavicle
5. interclavicle: bends inwards and protects fish.

Front 151

glenoid fossa (eusthenopterion, early gnathostome)

Back 151

faces posteriorly

Front 152

primitive living fish pectoral girdle

Back 152

similar to early gnathostome.

Front 153

chondrichthyes pectoral girdle

Back 153

no dermal elements; only scapulocoracoid

Front 154

history of the pectoral girdle, observed trends (4)

Back 154

1. reduction of dermal elements; increased size of endochondral elements (for support)
2. reduction in the number of bones (strength)
3. reorientation of the glenoid fossa (locomotion)
4. enlargement of dorsolateral over ventral components (locomotion)

Front 155

pectoral girdle in icthyostega: early tetrapod (3)

Back 155

1. 3 dermal: cleithrum, clavicle, interclavicle (complex, protects chest)
2. endochondral: scapulocoracoid
3. glenoid faces laterally

Front 156

early amniote pectoral girdle (3)

Back 156

1. 3 derma; cleithrum, clavicle, interclavicle
2. 2 endochondral: scapula and anterior coracoid: anterior becase synapsids later has posterior coracoid as well.
3. glenoid faces laterally

Front 157

what happens after early amniote pectoral girdle evolution???

Back 157

synapsids and sauropsids division!!!!

Front 158

modern reptiles (lizards) pectoral girdle (5 facts)

Back 158

1. 2 dermal: clavicle, interclavicle
2. 2 endochondral: scapula + anterior coracoid
3. glenoid faces laterally
4. cleithrum lost because it was heavy and clunky.
-sphenodon, better agility, more cartilage, lighter.

Front 159

archosaurs (aves, dinosaurs, crocks) pectoral girdle (4)

Back 159

1. 1-2 dermal: interclavicle, clavicle
2. endochondral: scapula + anterior coracoid
3. glenoid faces laterally
4. no clavicle

Front 160

aves pectoral girdle (3)

Back 160

1. 2 dermal: interclavicle + clavicle, fuse to form furcula
2. 2 endochondral: scapula + anterior coracoid
3. scapula no longer a huge role because huge sternum, for flying upstroke/downstroke.

Front 161

mammals pectoral girdle

Back 161

1. dermal clavicle (between sternum and scapula, connection)
2. endochondral: scapula

Front 162

components of the mammalian scapula (4)

Back 162

1. spine
2. acromion process
3. glenoid faces ventrally
4. no ventral plates of bone

Front 163

early synapsid pectoral girdle

Back 163

1. 3 dermal: cleithrum, clavicle, interclavicle
2. 3 endochondral: scapula, anterior coracoid, posterior coracoid
3. glenoid faces ventrolaterally (diagonal)

Front 164

monotreme pectoral girdle

Back 164

1. 2 dermal: clavicle (getting smaller), interclavicle
2. 3 endochondral: scapula, anterior coracoid, posterior coracoid
3. acromion process associated with clavicle, little scapular spine on anterior border
4. glenoid faces ventrolaterally

Front 165

therian mammal pectoral girdle

Back 165

1. 1 dermal: clavicle
2. 2 endochonral: scapula and very reduced posterior coracoid (coracoid process)
3. glenoid faces ventrally
4. new features: scapular spine, supraspinous fossa, well developed acromion process (clavicle articulation)

Front 166

coracoid trend with evolution

Back 166

both shrink. anterior completely disappears.

Front 167

homologies (3)

Back 167

1. infraspinous fossa of therians: primitive scapula
2. scapular spine of therians: anterior border of primitive scapula
3. coracoid process of therians: posterior coracoid

Front 168

synapsid to mammal transition, shift in limb stance (5)

Back 168

sprawling to upright
reptile: supracoracoideus muscle adducts humerus, raising trunk upwards
mammal: supra- and infraspinatus extends humerus, raising trunk upwards.
supracoracoideus and supra- and infraspinatus have same function even though different origins.
They are homologous, and can tell homologies because keep same nerves.

Front 169

pectoral girdle in modern reptiles (lizards)

Back 169

1. 2 dermal: clavicle, interclavicle
2. 2 endochondral: scapula and anterior coracoid
3. glenoid faces laterally
4. cleithrum lost.

Front 170

ontogeny of opossum reveals the transition

Back 170

in mammalian evolution, supracoracoideus (ventral) of reptiles split and migrated dorsally to new origin on scapula and is renamed supra- and infraspinatus. we don't have supracoracoideus because we're not on 4 limbs.

Front 171

cursorial mammals and change in pectoral girdle? (2)

Back 171

-reduce or lose clavicle (lose shoulder chest brace), very mobile scapulae.
-ventral part of pectoral girdle used to be more important, but dorsal becomes more important.

Front 172

evolution of pelvic girdle in tetrapods (6)

Back 172

1. 3 endochondral elements: ilium, ischium, pubis
2. number of bones is stable
3. fenestra appear
4. articulation with the vertebral column is strengthened (more sacral vertebrae)
5. dorsal area of muscle origin increases as ventral area decreases
6. acetabulum orientation shifts from lateral to ventrolateral.

Front 173

pelvic girdle in sharks

Back 173

not 3 parts, just one part.

Front 174

sarcopterygians and their pelvic girdle

Back 174

bones not well defined, but different parts.

Front 175

synapsid to mammal transition: pelvic girdle. (2)

Back 175

early synapsids had bigger pelvic girdle and became lighter.
ventral portion reduced in later mammals and dorsal part became more important with moving legs forward and backwards.

Front 176

how appendicular skeleton supports body weight in tetrapods (5)

Back 176

-pectoral girdle has no bony attachment at the top (dorsal) so looser.
-pelvic is tighter, more structure
-pelvic: hindlimbs are in mostly locomotion.
-front limbs: climbing, grabbing
-much less adaptive in back end.

Front 177

eusthenopteron (lobe-finned fish) and fins (2)

Back 177

can see single proximal element: humerus
can see two distal elements: radius, ulna

Front 178

acanthostega: early organisms and digits

Back 178

had more than 5

Front 179

homology of limb axis question (2)

Back 179

-in sarcopterygian, primary axis of development and branch off to one side
-after more embryology, primary axis is thru the ulna, and middle of your wrist (curves)

Front 180

primary axis in the arm, with embryological evidence (6)

Back 180

-condensation of mesenchyme
-elements form by splitting and budding
-axis thru ulna
-digit 4 appears first and digit 1 appears last
-digit 5's timing is variable.
-if digit 5 buds accidentally, 6 fingers.

Front 181

difference between chihuahua, homo sapiens, and great dane

Back 181

chihuahua: 4 fingers

Front 182

homeotic genes (2)

Back 182

-genes that regulate the identity of body regions. mutations in homeotic genes cause the transformation of one body part into another.

Front 183

hox genes (5)

Back 183

-homeotic genes found in linked clusters
-master genes
-genes expressed for budding of body parts.
-ancestral: hox genes expressed along body axis
-recent: posterior hox genes expressed in both appendages, so 2 sets of paired appendages (not just pectoral fins)

Front 184

autopod (3)

Back 184

-developed later with tetrapods, where axis cuts thru wrist.
-phase I and II hox expression was branched
-phase III hox expression is autopod

Front 185

diverse lines of evidence support the evolution of the tetrapod limb from a fin (4)

Back 185

1. comparative anatomy
2. fossil record
3. embryology
4. developmental genetics

Front 186

muscle function (very general) 2

Back 186

1. involved in nearly all functions and systems of the body: digestion, circulation, thermoregulation, locomotion, vision, hearing.
2. in all cases, muscles do their jobs by pulling, they never push.

Front 187

3 general types of muscle

Back 187

1. skeletal
2. cardiac
3. smooth

Front 188

skeletal muscle (7)

Back 188

1. associated with bones or cartilage
2. striated
3. multinucleate
4. strong contraction force
5. fatigues (varies)
6. voluntary control
7. develops from myotomes

Front 189

cardiac muscle (5)

Back 189

1. only in heart
2. striated, branched
3. does not fatigue
4. involuntary
5. develops from splanchnic mesoderm of lateral plate mesoderm (because heart is middle of body, not somite)

Front 190

smooth muscle (6)

Back 190

1. unstriated
2. associated with visceral functions
3. involuntary
4. located in walls of digestive tract and blood vessels: constrict blood vessels to perimeter of body. cold, temperature in peripheral go down, restrict blood flow by smooth muscle and keep blood and heat in core.
5. does not fatigue
6. develops from splanchnic mesoderm.

Front 191

3 general parts of skeletal muscle

Back 191

1. origin: fixed, proximal
2. insertion
3. belly

Front 192

5 kinds of skeletal muscle, shapes and fiber orientation

Back 192

A. strap
B. fusiform with tendon
C. unipennate
D. bipennate
E. multipennate: fibers going in many directions, converging on tendon

A and B are flat, strap-like, with parallel fibers
C, D, and E are pennate with angled fibers.

Front 193

muscle actions (8)

Back 193

1. flexion/extension: close and open joint
2. adduction/abduction: abduction is take away from midline, adduction is bring to midline
3. elevation/depression: usually about jaw
4. protraction/retraction: think about quadrapedal animals, prot is bringing forward, retract is swinging back
5. supination/pronation: palm upward, palm down (radius spin around ulna) some animals can with feet, some can't do with either.
6. constriction/dilation: close (eyes) and open (eyes, mouth). circular muscles arranged in circular fashion.
7. dorsiflex/plantar flex: dorsi is toes toward head, plantar is point toes away
8. rotation: around axis that runs thru joint. atlas and axis joint (dens into atlas) -> head rotate

Front 194

any and all movement require more than one muscle, three parts

Back 194

1. prime mover(s): like flexing arm with biceps
2. antagonist(s): controlling rate happens by contraction in triceps
3. synergist(s): hold other parts of body in place. important for muscles crossing multiple joints. want only 1 joint to bend. like if hand bend finger, so many muscles, so if no synergist, whole hand would bend. some people have problem with this, nothing resisting constriction of muscles.

Front 195

muscle contraction = (simple)

Back 195

development of tension in a muscle

Front 196

muscles are made up of...?

Back 196

fibers collected into bundles, all wrapped in connective tissue sheaths that are continuous with one another.

Front 197

basic unit of muscle contraction

Back 197

sarcomere

Front 198

contractile mechanism (2 explanations)

Back 198

-cross bridges on thick myosin filaments attach and detach from thin actin filaments as they slide past one another
-prongs make hooks, hook onto sliding filaments, shortening muscle: sliding toward each other in sarcomere.

Front 199

fibers in muscle: if connective tissue stretched..?

Back 199

like spring in muscle, pulled apart, then elastic energy.

Front 200

2 parts of muscles participating in contraction

Back 200

1. active contractile part (connective tissue)
2. passive elastic part (tendon)

Front 201

eye movement versus gastronemus movement

Back 201

1 nerve to 10 fibers if you want fine control (fine different portions of muscle at different times for fine movement like eyes). 1 nerve to 2000 fibers, with motor end plate attaching to various fibers for locomotion.

Front 202

muscle fibers are organized into motor units (4)

Back 202

-motor units: motor neuron and the muscle fibers it supplies.
-the # fibers/nerve varies according to function.
-fibers contract fully or not at all
-to increase force output, recruit more motor units.

Front 203

2 muscle fiber types

Back 203

1. tonic
2. twitch (phasic)

Front 204

tonic (6)

Back 204

1. slow, sustained contraction, low force
2. single fiber receives multiple motor end plates from single neuron
3. slow to fatigue
4. uncommon in body of mammals (excessive eye movement)
5. so if fire, stimulate 1 motor end plate, and 1 small portion of fiber contact that is attached.
6. can have gradual, smooth contraction and action.

Front 205

twitch (phasic) fibers (3)

Back 205

1. each fiber has single motor end plate
2. stimulus travels fast along fiber - all or none contraction
3. slow-twitch (red) and fast-twitch (white) fibers.

Front 206

fast-twitch fibers (white fibers) (6)

Back 206

1. poor stamina
2. fewer mitochondria
3. low in myoglobin: lower in oxygen
4. fast contraction rate
5. fatigue quickly (goes into oxygen debt)
6. used for burst activity

Front 207

slow-twitch fibers (=red fibers)

Back 207

1. good stamina
2. lots of mitochondria
3. high in myoglobin, higher in oxygen
4. slow contraction rate
5. fatigue slowly (aerobic metabolism)
6. used for sustained activity (postural muscles)

Front 208

most muscles in our bodies are composed of what kind of fibers??

Back 208

most muscles are mixture of fiber types, and muscle fiber composition can change with use.
turkey is actually pretty divided.

Front 209

ducks

Back 209

dark, long distance flier.

Front 210

muscle contraction and work

Back 210

-development of tension in a muscle usually results in shortening and work being done, but not always

work = force x distance
1. isometric contraction = no work
2. isotonic contraction = work (usually muscles shorten by 1/3)
3. negative work = muscle lengthens as it contracts (like triceps, or semimembranosus and tendinosus get longer when standing up from chair)

Front 211

4 parts of muscle performance

Back 211

force
speed
power = force x speed
working distance

Front 212

factors that affect muscle performance (3)

Back 212

1. muscle length
2. number of fibers
3. fiber orientation

Front 213

muscle fiber length

Back 213

resting vs. stretched: maximum force is produced when muscle is slightly stretched while contracting (1-1.3x). little stretched out to enhance ability of cross bridge of actin and myosin. if too short, completely overlapping and cross bridges can't form and actin and myosin mechanism doesn't work. fibers stretched too much: pulling actin component away from myosin, so cross bridges can't even start being formed.

Front 214

significance

Back 214

longer muscle can be effective over a greater absolute working distance than a shorter muscle. if longer, more sarcomere. also shortens more quickly because it has more sarcomeres in series. long muscle good for working distance, speed of contraction, but not as much force as short muscle.

Front 215

factor that affect muscle performance 2: number of fibers

Back 215

more fibers means more force. maximum force capability is roughly proportional to cross-sectional area.

Front 216

pennate vs. strap muscle of same weight

Back 216

pennate has more fibers and greater x-sectional area so more force capability (index of force) but strap muscles has longer fibers and so a greater working distance (distance over where joint can move and still produce force).

Front 217

what do you do if don't have room for muscle?

Back 217

pennate: can pack more power/force (index of force) in small space. like scapula.

Front 218

what do you do if you want to REALLY stretch?

Back 218

long muscle, working distance

Front 219

factor that affect muscle performance 3: fiber orientation

Back 219

more force is produced per gram of muscle if fibers are oriented in the direction of pull. strap better. pennate: muscle pulling at angle to direction of motion. so wasted force. but sometimes not enough room, so increase number of fibers to counteract loss by shorter, fibers in different directions, to balance.

Front 220

mechanics of bone-muscle systems (3)

Back 220

1. torque: a turning force. magnitude dependent on contraction force and mechanical advantage (leverage)
2. speed (velocity) of movement
3. range of movement (working distance)

Front 221

lever

Back 221

any rigid bar or strut that transmits force by turning or tending to turn at a point

Front 222

inforce (Fi)

Back 222

that produced by the muscle

Front 223

outforce (Fo)

Back 223

resultant force

Front 224

effective lever arm (L, moment arm)

Back 224

perpendicular distance between line of action of the force and the pivot.

Front 225

equation of forces 1, 2 and lever 1, 2

Back 225

F1 x L1 = F2 x L2

Front 226

mechanical advantage

Back 226

Li/Lo
ratio of the in-lever to the out-lever.

Front 227

runner verses digger

Back 227

runner has small Li to Lo ratio
digger has larger Li to Lo ratio

Front 228

moment arm (Li) changes as...?

Back 228

ulna swings. it is maximum at only one position, usually resting position

Front 229

what is outlever?

Back 229

distance between pivot and the position of resistance

Front 230

to increase torque (Fo)

Back 230

1. increase contraction force (Fi)
2. Increase mechanical advantage (Li/Lo)

Front 231

why don't all muscles have big in-levers? (3)

Back 231

1. problems of bulk
2. problems of over-stretching
3. need for speed of movement.

Front 232

if speed of movement is important...

Back 232

place muscle insertion close to joint. if 2 muscles closer and farther to joint are contracted the same absolute distance and same time, the muscle closer will have a bigger angle, degree of motion than the muscle farther away.

Front 233

velocity ratio

Back 233

Lo/Li, to maximize speed of motion, increase this.

Front 234

if maximizing the range of movement is important...

Back 234

minimize muscle stretching by...:

1. lengthening muscle
if longer muscle, longer distance to contract before no longer effective. so minimize muscle stretching because if stretched too much, no longer effective.

2. placing either the insertion or origin closer to the joint: if origin or insertion closer to joint, going to move smaller arc relative to joint, not going to get as stretched.

Front 235

hippos

Back 235

-mandible with huge expanded angle.
-lengthen massater
-can be 1 1/3 stretched, but not necessary.
-one of attachments close to joint. so muscle will not be as stretched when goes thru arc of motion (not be as stretched with bigger angle change)
-pig: more stretch relative to resting, not as effective moving distance of muscle.

Front 236

determining homologies among muscles

Back 236

1. position and relationship to other muscles
2. embryology and paleontology: ontogeny of opossum, migration of single body supracoideus, arms and scapula split into stuff, so reinforces what nerves tell.
3. nerve supply: spinal nerves are conservative and they stick with muscle they innervate. tracing and knowing innervation -> clue to homology.

Front 237

why are muscles hard to determine evolutionarily?

Back 237

because they move, split, join, migrate to new origins and insertions.

Front 238

2 primary sources of muscles

Back 238

1. somites (myotomes)
2. lateral plate mesoderm

Front 239

lateral plate mesoderm 2 parts

Back 239

1. smooth - visceral muscles (behind head): associated with back tube and associated organs
2. striated - somatic, part of hypaxial: muscle of flanks, connects to appendicular skeleton like limbs and appendages

Front 240

somite or myotomes 4 parts

Back 240

1. axial and appendicular
2. hypobranchial: ventral part of pharynx and throat.
3. branchiomeric (visceral arc): gills. since 1st gill is jaw, associated with jaw.
4. extrinsic eye: mechanically moving your eye
2-4 are head and pharynx related

Front 241

head: somite and somitomeres, developing head of embryo, ontology stuff

Back 241

all cranial and visceral arch muscles are somatic.

behind head, very regular. myotomal segments. all line up, along body of developing fetus. looks like fish. simple segmented myotomal muscle arrangement.
at head, very confusing. thought was all derived from visceral because right next to gills and pharynx. actually myotomes for head
4 somite/myotome 1,2,3,4: these are anterior most somites. these look like somites that go all the way down body discretely and individually

1-7: the way head is organized and arranged. curve downward toward throat region and create branch or gill muscles. they're connected and believed to have been individuals before, and there are 4 parts also, 4 parts of original somites: 1&2, 3&4, 5&6, and 7. 8 lost in evolutionary history. 1-7 contribute to anterior branchial arches and mandibular muscles -> jaw and hyoid. then muscles of visceral (gill) arches.

so... know that all these parts of the head are all SOMATIC, not lateral plate mesoderm.

Front 242

3 parts in embryo muscles

Back 242

extrinsic ocular muscles (eye ball)
branchiometric muscles
hypobranchial muscles: tongue, larynx, pharynx.

Front 243

skeletal components of a single gill arch

Back 243

1. pharyngobranchial
2. epibranchial
3. ceratobranchial
4. hypobranchial

Front 244

muscular components of gill arches of fishes

Back 244

I. branchiometric:
a. levators (expand the gill, cucullaris): pharyngobranchial
b. adductors (compress, pull): epi and cerato
c. constrictors (compress, pull): epi and cerato

II. hypobranchial
a. hypobranchialis (expand): hypobranchial

Front 245

synovial joint

Back 245

squeeze and expand like accordion, muscles attached.

Front 246

because 1st epi and cerat become jaws... adductors and constrictors...?

Back 246

close jaws.

Front 247

jaw muscle of fishes

Back 247

branchiomeric:
a. adductor mandibulae (closes jaw; homolog of adductors of arch 1)
hypobranchial
a. coracomandibularis (opens jaws; homologous with hypobranchials of gills)

Front 248

early tetrapods: arch 1

Back 248

branchiomeric
a. adductor mandibulae (arch 1) has split to form 2 muscles with different line of action
1. adductor externus
2. pterygoideus (smaller, internal)

Front 249

early tetrapods: arch 2

Back 249

1. levator of arch 2 becomes depressor mandibulae (opens jaws, small because gravity)
2. constrictor of arch 2 becomes sphincter colli (skin muscle around neck, assist in swallowing, squeeze from outside, simple. humans complex, squeeze in inside)

Front 250

jaw muscles of early tetrapods: arch 3-7

Back 250

1. branchiomerics
a. levators become trapezium, others become sternocleidomastoid complex, laryngeal muscles
2. hypobranchials
a. hyoid apparatus and tongue support muscles: swallowing aid, holds adams apple. fish don't chew like tetrapods so no tongue, but land animals have a tongue.

Front 251

evolution of jaw musculature in tetrapods (step 1)

Back 251

step 1: shift in orientation of the adductor externus to provide better mechanical advantage when the jaws are closed. slanted to vertical. slanted good to initiate closure. but not good when already bit down. so vertical better for power. amphibian (early) has to chase fast fish, so accelerate and initiate bite. adductor externus vertical in reptile has mechanical advantage to crush and cut up prey.

Front 252

evolution of jaw musculature in tetrapods, because of vertical muscles.

Back 252

associated with this, reptiles develop deeper skulls to provide more room for larger adductor muscles. functional implication: stronger bite especially when jaws are near closed.

Front 253

evolution of jaw musculature in tetrapods: therapsid to mammal (early synapsid to early cynodont)

Back 253

early synapsid similar to reptiles with a poor mechanical advantage for jaw adductors. advanced cynodonts show a number of improvements, including evolution of the coronoid process (lever) of the dentary.

Front 254

evolution of jaw musculature in tetrapods: therapsid to mammal 2.

Back 254

2. adductor externus enlarges and dives into temporalis and masseter outside in mammals, new (origin on zygomatic arch)

Front 255

evolution of jaw musculature in tetrapods: therapsid to mammal 3.

Back 255

develop new jaw opening muscle: digastric (from constrictors of arches 1-2) 2 bellies.

Front 256

why all these changes of jaw muscles??? (2)

Back 256

1. evolution of middle ear apparatus (reduced post dentary bone for hearing and biting)
2. improved, more complex jaw mechanisms: larger jaw muscles, improved mechanical advantage, side-to-side chewing with precise tooth occlusion (coming together of top and bottom teeth).

Front 257

so... the 3 jaw musculature changes in tetrapods summary?

Back 257

1. shift in orientation of adductor externus to provide better mechanical advantage when jaws closed
2. adductor externus enlarges and divides into temporalis and masseter
3. develop a new jaw opening muscle: digastric

Front 258

temporalis, masseter, and coronoid process contribute to...?

Back 258

coronoid process stick up in orbit so muscles can attach on both sides. temporalis inside coronoid, outside masseter outside, allows jaws to swing side to side: creation of a muscular sling for the jaws.

Front 259

how do you make jaws swing right?

Back 259

contract left pterygoideus m. and right masseter m.

Front 260

anapsid -> synapsid -> mammalian condition of skull. changes?

Back 260

muscles for jaw used to be inside, now outside the solid braincase.

Front 261

why did side-to-side chewing and precise dental occlusion evolve? (2) and also side note

Back 261

better chewing abilities
1. increase rate of passage of food (endothermy)
2. expand range of food choices (especially plant matter, hard to digest. herbivores evolved after carnivores)

also increase surface area so digest faster. saliva digestion.

Front 262

summary of mammalian branchiomerics and hypobranchial muscles (6)

Back 262

branchiomerics:
1. temporalis: closes jaw arch 1
2. masseter: closes jaw 1
3. pterygoid: closes jaw 1
4. digastric: opens jaw 1 and 2
5. muscle of facial expression 2, homologous with sphincter of colli of reptiles: thin muscles, can be hard to duplicate because split and subdivided. but innervated by same nerve from sphincter colli.
6. trapezius and sternocleidomastoid 3-7

Front 263

fishes and axial musculature

Back 263

locomotor organ and that's it!

Front 264

tetrapods and axial musculature (4)

Back 264

1. movement of vertebral column
2. support of abdominal viscera
3. breathing
4. suspension of trunk on pectoral girdle.

Front 265

segmental arrangement in fishes

Back 265

1. epaxial (above lateral septum)
2. hypaxial (below lateral septum)

Front 266

tetrapods: necturus and rabbit and axial musculature (3)

Back 266

reduce size of axial musculature but increase subdivision

1 set of muscles of necturus
epaxial divided in rabbits, move in all ways.

Front 267

epaxial: 3 parts (before it was one giant area)

Back 267

a. transversospinalis (medial-most)
b. longissimus
c. iliocostalis (lateral most) - rib

Front 268

lateral-most and medial-most of epaxial and mammals and reptiles

Back 268

reptiles: lateral-most component is largest because mediolateral movement: mechanical advantage with lever.
mammals: medial most component importnat for dorsoventral.

Front 269

3 components of hypaxial muscles

Back 269

1. dorsomedial (subvertebrals, so ventral part of dorsal)
2. lateral (obliques, intercostals, serratus ventralis, rhomboideus)
3. ventral (rectus abdominis)

Front 270

hypaxial muscle functions (4 and which muscle?)

Back 270

1. breathing: intercostals
2. abdominal support: rectus abdominis and obliques
3. trunk suspension (serratus ventralis, rhomboideus, trapezius* and pectoralis*)
4. support of vertebral column: rectus abdominis.

Front 271

trunk suspension in reptiles

Back 271

ventral bony connection to sternum via clavicles and coracoid. if push in one limb, push against the other side, muscular connection via the serratus ventralis and supracoracoideus.

Front 272

trunk suspension in mammals (3)

Back 272

no bony connection between the forelimb skeleton and trunk (lose coracoid and reduce clavicle)

4 muscles form the attachment: rhomboideus, trapezius, serratus ventralis, pectoralis.

LOOSE

Front 273

support of vertebral column in mammals

Back 273

-rectus abdominis acts as string of a bow. resist sway back and collapse of backbone.
-reversal bow part, splenius pulls back and holds head up. resisting tendancy to sway back, support structure.
-rectus abdominis assist your back and support weight.
-tail and head act as cantilevers, dorsiflexing spine.
-horses: note height and orientation of thoracic neural spines because of huge head to support back (relatively stiff) and keep it back.
and presence of elastic nuchal ligament to raise head.

Front 274

appendicular limb musculature: fish with simple arrangement: in vertebrate ontogeny, limb muscles first appear as ...?

Back 274

dorsal and ventral mass (muscle) on the limb buds. all limb muscles are derived from these two masses.

Front 275

appendicular musculature: human in anatomical position, limbs!!!

Back 275

1. forelimb: flexors, anterior; extensor, posterior.
2. hindlimb: flexors, posteromedial on back of leg; extensors, anterolateral.

Front 276

appendicular musculature in tetrapods

Back 276

-same as humans in hind limbs, but backwards switches in forefore limbs.
-extensor on embryo flexes to form elbow. so flex and make elbow and knee, rotating to decide which way.
-they walk with hands prone, extensors twisted forward.
-note: dorsal (extensor) mass of fishes is twisted on front limb, and anterior on hind limb. the ventral (flexor) mass is also twisted on the front limb and posterior on the hind limb.
-lions have radius that turns and twists across with muscles associated with it.

Front 277

speed equation

Back 277

speed = stride length x stride frequency

Front 278

3 relevant parameters for speed in running

Back 278

1. top speed (maximum running speed)
2. maximum aerobic sustainable speed
3. acceleration

Front 279

trends with speed and stamina? (2)

Back 279

-larger animals faster with more stamina
-mammals and reptiles have similar top speeds but reptiles have poor stamina because reptiles use anaerobic to sustain muscles, not endotherms.

Front 280

over past 65 millions of years...

Back 280

-mammals have tended to get more cursorial in response to environmental change.
-cursocial: run fast and far
-before, big lumpy
-then got cursorial with slender limbs to escape from predator and to catch prey
-predator prey arms race
-change in environment: green, climbing, run short -> forest opens up, fun faster, longer legs. happened in different places at the same time, so converged independently.

Front 281

so goal in evolutionary game in cursoriality is...? (3)

Back 281

increase stride length, stride frequency, or both.

Front 282

to increase stride length...: (2)

Back 282

1. increase limb length relative to body size (leopard versus cheetah)
a. lengthen bones by distal elongation
b. change in foot posture
c. increase scapular mobility
2. increase flexion/extension ability of the spine

Front 283

distal elongation (definition and 3 ways to do it)

Back 283

evolution of longer legs occurs by lengthening distal segments relative to proximal segments

-concentrates muscle mass close to trunk so lighter at distal
-allows for long energy-saving elastic tendons in distal.
-greater foot excursion (swing) for a given contraction because close to center of rotation

Front 284

change foot posture why? and 3 kinds

Back 284

can produce longer leg without increasing limb mass
1. plantigrade: metatarsels parallel to ground
2. digitigrade: on tippy toes
3. unguligrade: on toes, standing on toes, lengthening limbs.

Front 285

increase scapular mobility

Back 285

-eliminate clavicle
-develop narrow, deep chest
-allows scapula to swing force and aft.
-deer has no joint
-scapula swing allows forelimbs to reach farther -> adding length of limb by changing joint and adding another element with shoulder moving.

Front 286

increase flexion/extension ability of the spine (extension range of spine) to increase stride length (5)

Back 286

-back dorsiflexes and hindlimbs travel farther
-back extends and forelimbs travel farther
-scapula swing allows forelimb to reach farther.
-alter zygapophyses in lumbar region to enhance flexion ability.
-lengthen the lumbar region.

Front 287

larger animals like horses?

Back 287

less spinal flexion in large bodied mammals

Front 288

increase stride frequency by...? (2, 3 subdivisions)

Back 288

1. move muscle insertions closer to joints (because flexing muscles more is energetically expensive)
2. increase the number of joints involved in forward motion:
a. add scapular mobility
b. add spinal flexion and extension
c. change foot posture.

Front 289

what do you call muscles close to fulcrum?

Back 289

high gear muscle. closer: bigger arc, smaller contraction, move more, less time, more motion.

Front 290

velocity, and how increasing number of joints is wonderful

Back 290

velocity = speed in a given direction
all joint/limb velocities are summed up.

Front 291

speed and increased body mass: problems of size (2)

Back 291

-as body length increases x times, mass (volume) will increase x^3 and surface areas will increase x^2 times.
-bone and muscle strength are a function of cross-sectional area so their strength will lag behind the volume they have to support if increase occurs via isometry.

Front 292

how do elephants solve this problem of increased body mass?

Back 292

-elephants have much thicker bones (to increase cross sectional area to support): 14% for elephant, 4% for shrew.

Front 293

muscle is always about 40-45% body mass. how can this be and how is this solved? (4)

Back 293

large animals reduce the need for lots of muscle by reducing the loads on the muscles

1. stiffen the back
2. reduce the mass of limbs
3. concentrate muscle mass proximally
4. alter limb posture to have relatively erect, unbent limbs.

Front 294

3 of the solutions to the elephant muscle mass situation do what?

Back 294

reduce the problem of moving an oscillating limb. in an oscillating system, energy is expended to reverse direction.

Front 295

kinetic energy of a rotating body. and so what? (3)

Back 295

0.5 IW^2 where I=moment of inertia and w=angular velocity.
-moment of inertia includes both mass and the distribution of the mass. mass farther from axis of rotation "costs" more to move.
-so move muscle closer to body

Front 296

save energy, reduce cost of oscillation by..? stiffening back. how do you do this? (3)

Back 296

1. high broad neural spines
2. u-shaped articulations between zygapophyses
3. no up and down or side to side motion in back

Front 297

reduce limb mass by..? (4)

Back 297

a. reducing muscles that abduct/adduct limbs (just forward)
b. have tight interlocking joints: reduce muscle in joints.
c. reducing distal bones (bone fusion and loss)
d. evolve passive (no energy cost) mechanisms to perform tasks done by muscles. for example, the horse knee-locking mechanism)

Front 298

concentrate muscle mass proximally, making it less costly to reverse limb direction, by: (2)

Back 298

a. distal elongation with long tedinous insertions
b. replacing muscle with ligamentous slings (elastic springs)

Front 299

elephants are considered to be...?

Back 299

graviportal: erect limb posture; long limbs without distal elongation fastest gait: fast walk.

Front 300

fossorial digging mammals (importance in 1 sentence)

Back 300

selection for strength over speed

Front 301

3 types of fossorial mammals

Back 301

1. scratch diggers (like dogs)
2. humeral rotation diggers (moles, like swimming)
3. tooth diggers (naked mole rat)

Front 302

diggers display adaptations to...? (4)

Back 302

1. maximize out-force of forelimb
2. improve their ability to break up and transport soil
3. resist rearward forces when digging
4. prevent dirt from entering their mouths, ears, and eyes

Front 303

to maximize outforce... (1 equation, 5 scenarios)

Back 303

-increase ratio of Li/Lo
-long olecranon process
-short forelimb and phalanges
-muscles insert far from joints.
-increase size of muscles
-large area of muscle origin and insertion

Front 304

humeral rotation diggers have what..?

Back 304

large teres major, spins humerus around its long axis.

Front 305

how do diggers improve their ability to break up and transport soil?

Back 305

long, rapidly growing claws.

Front 306

adaptations to resist rearward forces when digging?

Back 306

1. strong sacrum
2. large hindlimb muscles capable of exerting strong groundward force.

Front 307

adaptations to prevent dirt from entering their mouths, ears, and eyes?

Back 307

1. reduced or absent eyes (dark anyway)
2. reduced or absent external ear opening
3. small nares
4. tight closing teeth (lips behind)