Lecture 3

Question 1

What are some skeletal tissues functions?

Answer 1

Support, protection, feeding, breathing, locomotion, mineral storage, endocrine (hormones), hematopoiesis (blood cells)

Question 2

Skeletal tissue types

Answer 2

Cartilage, Bone, Bone Marrow

Question 3

What are mature chondroblasts?

Answer 3

Chondrocytes

Question 4

What do the mechanical properties of cartilage depend on?

Answer 4

all come down to the relative abundance of these components in the matrix (extracellular matrix)

Question 5

True or false: cartilage is vascular

Answer 5

false: cartilage is avascular

Question 6

How do gas & nutrients exchange from chondrocytes?

Answer 6

Diffusion

Question 7

What is an osteoid

Answer 7

bone extracellular matrix

Question 8

True or false: bone is vascular

Answer 8

true

Question 9

What do osteoblasts produce

Answer 9

osteocytes

Question 10

what do osteoclasts come from

Answer 10

fusion of macrophages

Question 11

What do osteoclasts do?

Answer 11

secrete enzymes, eat away at extracellular matrix of the bone and take away

Question 12

What is bone homeostasis regulated by?

Answer 12

osteocytes embedded in the matrix

Question 13

What is the structural composition of bone dependent on?

Answer 13

bone homeostasis & resorption

Question 14

How is dermal bone formed

Answer 14

Formed within the dermis through intramembranous ossification

Question 15

What is dermal bone made of

Answer 15

calcium carbonate

Question 16

What do crocodilians use osteoderms for?

Answer 16

to regulate blood pH and temperature

Question 17

What intermembranous ossification

Answer 17

Bone forms on its own within a membrane (Membrane bone, Dermal bone)

Question 18

What is endochondral ossification

Answer 18

a template made of cartilage is replaced by bone during development

Question 19

Explain the steps of endochondral ossification

Answer 19

A template for the bone is made out of cartilage, Chondrocytes are now cut off from oxygen and nutrients so they start secreting help signals and the cartilage ECM begins to break down, Blood vessels are attracted to the chondrocyte’s help signals and infiltrate the center of the cartilage
Osteoblasts and osteoclasts hitch a ride on the blood vessels into the center of the cartilage template, Spongy (interior) and compact (exterior) bone replace the cartilage from the inside out.
This leaves a hollow center (medullary cavity) in the bone which is later filled with bone marrow and larger blood vessels

Question 20

What is bone marrow

Answer 20

fatty (adipose) tissue which sometimes contains hematopoietic and osteogenic stem cells

Question 21

Describe the skeletal tissue in agnathans

Answer 21

no bone, non-mineralized cartilage

Question 22

Difference in dermal bone between extinct and extant agnathans

Answer 22

extinct: dermal bone, extant: no dermal bone

Question 23

Describe the skeletal tissue in gnathostomes

Answer 23

reduction in cartilage, mineralized endo-skeletons

Question 24

Describe the skeletal tissue in chondrocytes

Answer 24

mineralized cartilage in endoskeleton, no bone

Question 25

Describe the skeletal tissue in osteichthyes

Answer 25

cartilage, bone (membrane), bone (endochondral ossification) - bone marrow (only hematopoietic in tetrapods)

Question 26

True or false: Neural crest cells are a vertebrate monophyletic group

Answer 26

false: Neural crest cells are a vertebrate synapomorphy

Question 27

What has been been hypothesized about neural crest cells

Answer 27

what allowed vertebrates to develop the necessary structures to switch from filter feeding to active predation

Question 28

Where is the chondrocranium?

Answer 28

surrounds the brain and encloses the sensory organs. Articulates with notochord

Question 29

Where is the slachnocranium?

Answer 29

supports the gills and contributes to the jaws / inner ear bones. Highly derived.

Question 30

what is the dermatocranium?

Answer 30

dermal bones that contribute to the jaws, brain case, facial bones. Encloses the chondrocranium and splanchnocranium (made of membranous bone, never cartilage)

Question 31

What happens in the chondrocranium during embryonic development?

Answer 31

During embryonic development two pairs of cartilaginous bars and 3 pairs of capsules develop, The parachordals associate with the notochord

Question 32

What happens to the capsules formed during embryonic development?

Answer 32

The capsules, bars and notochord eventually fuse and surround the brain and sensory organs

Question 33

True or false: In lineages with a dermatocranium the chondrocranium is only the base of the brain case

Answer 33

true

Question 34

What does the splanchnocranium develop from?

Answer 34

from the pharyngeal arches

Question 35

What does the splanchonocranium arise from during embryonic development?

Answer 35

pharyngeal arches

Question 36

What different functions are pharyngeal slits used for in non-vertebrate chordates vs. aquatic gill breathing vertebrates

Answer 36

used for filter feeding vs. some of them develop into the structures that houses the gills

Question 37

What is each pair of gills supported by?

Answer 37

a visceral arch, alternating with gill slits leading to gill pouches

Question 38

How many arches are in extant vertebrates?

Answer 38

7

Question 39

True or false: Chondrichthyes have a dermatocranium

Answer 39

false: Chondrichthyes do not have a dermatocranium

Question 40

What happens to the first 2 pharyngeal arches in gnathostomes?

Answer 40

develop into two cartilaginous structures that form the beginning of the jaw

Question 41

what happens to the mandibular and hyoid arch in Chondrichthyes?

Answer 41

the embryonic structures remain in place and form the Jaw

Question 42

where is the hyomandibular (H)

Answer 42

extends from otic area of chondrocranium

Question 43

where is the certaohyals (C)

Answer 43

about posterior end of the palatoquadrate and mandibular cartilage

Question 44

What is the main side of attachment for the jaw to the chondrocranium

Answer 44

the hyoid arch

Question 45

What form of jaw suspension do sharks have? Describe where it is and its function.

Answer 45

hyostylic ( jaw connects through the hyomandibula) - permits the shark to protact its jaws

Question 46

What do pharyngeal arches 3-7 do?

Answer 46

forms 5 brachial arches which support the 5 pairs of gills

Question 47

What happens to the cartilage splanchnocranium in many species?

Answer 47

eventually ossified through endochondral ossification?

Question 48

What does the operculum do in gill breathing bony fishes?

Answer 48

made of dermal bone that covers the gills and helps with buccal pumping like the spiracle - instead of spiracle

Question 49

What does the posterior position of the palataquadrate become in Non Mammalian Tetrapods

Answer 49

quadrate bone

Question 50

what does the posterior portion of Meckyl's cartilage become in Non Mammalian Tetrapods

Answer 50

articular bone

Question 51

What does the lower jaw connect by in non mammalian tetrapods?

Answer 51

articular hinge

Question 52

What do mammals use to attach the mandible (lower jaw) to the rest of the skull

Answer 52

dermal bones

Question 53

What does a secondary palate do in Mammals, Crocodilians, and some lizards?

Answer 53

separates the mouth from the nasal cavity

Question 54

What is the advantage of separating the mouth from the nasal cavity?

Answer 54

Can eat and breath at the same time