Lecture 3 Flashcards
What is the centrum?
A structure that sits around the notochord
What is the neural arch?
A structure around the dorsal hollow nerve cord
What is the haemal arch?
A structure that may be around the blood vessels
Explain the role of hox genes in vertebrate evolution
They regulate the expression of genes that control body shape, especially around the body’s axis.
In regards to hox genes, what do vertebrates have?
They have a duplication of the entire hox gene complex
What kind of layer is the neural crest?
A germ layer
What are vertebrates?
Quadroblastic
Explain briefly the development of the neural crest cells. (Think the shape of a raindrop)
The neural crest cells develop adjacent to the neural tube and migrate out along define routes to contribute to various organs
What does the neural tube enclose as/in?
The neurocoel
Name some of the things that derive from the neural crest
Facial dermis, dentine, peripheral N.S, lower jaw, sensory capsules and heart connective tissue
Name the general patterns seen in higher vertebrates
There’s an increase in size, more complex regulatory systems, development of organs needed for this and the development of muscles and bone.
Explain the reasons behind the general vertebrate patterns
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
Why do vertebrates need protective integument?
To prevent organs from rubbing together/friction
What does the coelom in an embryo contain?
Internal organs.
Name the cavities for the internal organs in the coelom of an embryo
Pleuroperitoneal cavity (around viscera), pericardial (around heart). These are lined with thin mesodermal sheets: peritoneum & pericardium
What is the nephrotome?
A section of the mesoderm that eventually gives rise to the kidney and gonads
What do somites give rise to?
Skin, muscle and the back of the skull
What is the unsegmented lateral plate in the mesoderm?
Forms all internal nonsegmented portions: Connective tissue, blood vas. system, mesenteries, coelom linings and reproductive system ducts
What are the exceptions to the segmentation rule?
Locomotory muscles, limb bones, tendons and ligaments
Name the 5 types of tissue in vertebrates
Epithelial, connective, vascular, muscular and nervous
What does the mesodermal fibrous protein collagen make up?
Softer tissue of organs, organic matrix of bone and the tough tissues of tendons and ligaments
What is the fibrous protein (not collagen) that is only found in vertebrates? What layer is it primarily and where is it found?
Keratin, primarily ectodermal, found in the epidermis
What are the functions of the epidermis/dermis in the glands of a vertebrate?
Pheromones, lubrication and defence
What are the functions of the epidermis/dermis in the epidermis of a vertebrate?
Hair, scales, feathers and claws
What are the functions of the epidermis/dermis in the dermis of a vertebrate?
Bone dermis and the scales of sharks
What are the three layers of skin in order from top to bottom?
Epidermis, dermis and subcutaneous tissue/hypodermis
What is mineralization? Give an example
When inorganic ions are deposited in the organic matrix of tissue to harden. Hydroxyapatite, a calcium/phosphorus compound that helps to form bones
Name the 6 tissues that become mineralized in vertebrates
Enamel, dentine, bone, cartilage (skeleton of sharks), enamaloid and cementum (fastens teeth into sockets)
What are the two types of bone?
Dermal bone: Forms in the skin without a cartilagenous precursor. Endochondral bone: Formed inside cartilage.
Give a example of an organism with dermal bone
A dunkleosteus was a placoderm that had an armoured exoskeleton made of dermal bone. The primitive bone type found in fossil jawless vertebrates
Name where dermal and endochondral bone is found in humans
The braincase (dermal) and the endoskeleton (endochondral bone that follows initial cartilage growth)
What is the chondrocranium, splanchnocranium and dermatocranium
Around the brain (chondro), gill support (splanch) and dermatocranium (outer cover, forming skin
Grab a piece of paper or explain what the axial skeleton of primitive gnathostomes looks like
Top to bottom is the d.h nerve cord, notochord & blood vessel. Top and bottom of these three are the arches
What are the arches/spines called in primitive gnathostomes?
Neural spine, neural arch and interneural arch. At the bottom is the Pleurocentrum and intercentrum
Name the four major systems associated with energy acquisition and support of the metabolism.
Feeding & digestion, respiration & ventilation, cardiovascular system and excretory & reproductive systems
