Lecture 3

Question 1

What is the centrum?

Answer 1

A structure that sits around the notochord

Question 2

What is the neural arch?

Answer 2

A structure around the dorsal hollow nerve cord

Question 3

What is the haemal arch?

Answer 3

A structure that may be around the blood vessels

Question 4

Explain the role of hox genes in vertebrate evolution

Answer 4

They regulate the expression of genes that control body shape, especially around the body’s axis.

Question 5

In regards to hox genes, what do vertebrates have?

Answer 5

They have a duplication of the entire hox gene complex

Question 6

What kind of layer is the neural crest?

Answer 6

A germ layer

Question 7

What are vertebrates?

Answer 7

Quadroblastic

Question 8

Explain briefly the development of the neural crest cells. (Think the shape of a raindrop)

Answer 8

The neural crest cells develop adjacent to the neural tube and migrate out along define routes to contribute to various organs

Question 9

What does the neural tube enclose as/in?

Answer 9

The neurocoel

Question 10

Name some of the things that derive from the neural crest

Answer 10

Facial dermis, dentine, peripheral N.S, lower jaw, sensory capsules and heart connective tissue

Question 11

Name the general patterns seen in higher vertebrates

Answer 11

There’s an increase in size, more complex regulatory systems, development of organs needed for this and the development of muscles and bone.

Question 12

Explain the reasons behind the general vertebrate patterns

Answer 12

They can’t rely on diffusion alone for respiration/food so the need blood transport. They become more active so it requires organs capable of working quickly & mobility requires muscle and bone with some protection

Question 13

Why do vertebrates need protective integument?

Answer 13

To prevent organs from rubbing together/friction

Question 14

What does the coelom in an embryo contain?

Answer 14

Internal organs.

Question 15

Name the cavities for the internal organs in the coelom of an embryo

Answer 15

Pleuroperitoneal cavity (around viscera), pericardial (around heart). These are lined with thin mesodermal sheets: peritoneum & pericardium

Question 16

What is the nephrotome?

Answer 16

A section of the mesoderm that eventually gives rise to the kidney and gonads

Question 17

What do somites give rise to?

Answer 17

Skin, muscle and the back of the skull

Question 18

What is the unsegmented lateral plate in the mesoderm?

Answer 18

Forms all internal nonsegmented portions: Connective tissue, blood vas. system, mesenteries, coelom linings and reproductive system ducts

Question 19

What are the exceptions to the segmentation rule?

Answer 19

Locomotory muscles, limb bones, tendons and ligaments

Question 20

Name the 5 types of tissue in vertebrates

Answer 20

Epithelial, connective, vascular, muscular and nervous

Question 21

What does the mesodermal fibrous protein collagen make up?

Answer 21

Softer tissue of organs, organic matrix of bone and the tough tissues of tendons and ligaments

Question 22

What is the fibrous protein (not collagen) that is only found in vertebrates? What layer is it primarily and where is it found?

Answer 22

Keratin, primarily ectodermal, found in the epidermis

Question 23

What are the functions of the epidermis/dermis in the glands of a vertebrate?

Answer 23

Pheromones, lubrication and defence

Question 24

What are the functions of the epidermis/dermis in the epidermis of a vertebrate?

Answer 24

Hair, scales, feathers and claws

Question 25

What are the functions of the epidermis/dermis in the dermis of a vertebrate?

Answer 25

Bone dermis and the scales of sharks

Question 26

What are the three layers of skin in order from top to bottom?

Answer 26

Epidermis, dermis and subcutaneous tissue/hypodermis

Question 27

What is mineralization? Give an example

Answer 27

When inorganic ions are deposited in the organic matrix of tissue to harden. Hydroxyapatite, a calcium/phosphorus compound that helps to form bones

Question 28

Name the 6 tissues that become mineralized in vertebrates

Answer 28

Enamel, dentine, bone, cartilage (skeleton of sharks), enamaloid and cementum (fastens teeth into sockets)

Question 29

What are the two types of bone?

Answer 29

Dermal bone: Forms in the skin without a cartilagenous precursor. Endochondral bone: Formed inside cartilage.

Question 30

Give a example of an organism with dermal bone

Answer 30

A dunkleosteus was a placoderm that had an armoured exoskeleton made of dermal bone. The primitive bone type found in fossil jawless vertebrates

Question 31

Name where dermal and endochondral bone is found in humans

Answer 31

The braincase (dermal) and the endoskeleton (endochondral bone that follows initial cartilage growth)

Question 32

What is the chondrocranium, splanchnocranium and dermatocranium

Answer 32

Around the brain (chondro), gill support (splanch) and dermatocranium (outer cover, forming skin

Question 33

Grab a piece of paper or explain what the axial skeleton of primitive gnathostomes looks like

Answer 33

Top to bottom is the d.h nerve cord, notochord & blood vessel. Top and bottom of these three are the arches

Question 34

What are the arches/spines called in primitive gnathostomes?

Answer 34

Neural spine, neural arch and interneural arch. At the bottom is the Pleurocentrum and intercentrum

Question 35

Name the four major systems associated with energy acquisition and support of the metabolism.

Answer 35

Feeding & digestion, respiration & ventilation, cardiovascular system and excretory & reproductive systems