Lab 2 Terminology Flashcards
1
Q
animal pole (3)
A
- animal pole is located at the top of the egg
- has a lower concentration of yolk than the vegetal pole
- cells that divide near the animal pole are smaller than cells near the vegetal pole due to the lack of yolk
2
Q
vegetal pole (3)
A
- vegetal pole is located at the bottom of the egg
- has a higher concentration of yolk than the animal pole
- cells that divide near the vegetal pole are larger than cells near the animal pole due to the abundance of yolk
3
Q
blastocoel (3)
- defintion (2)
- function
A
- hollow space inside the blastula formed during blastula formation
- lined by undifferentiated/non-specialized cells
- no specific function, just a step that has to occur during development
4
Q
blastopore
A
- opening in the blastula outer surface
5
Q
archenteron (5)
A
- “early gut”
- new space formed within the embryo during gastrulation
- gives rise to the lumen of the digestive tract
- this space is lined by endoderm cells
- completely displaces the blastocoel
6
Q
coelom (2)
- development
- fate
A
- hollow space that forms between the two hypomere mesoderm layers
- gives rise to major body cavities of the adult
7
Q
mesolecithal (4)
- yolk size
- vertebrate type
- blastocoel and cell size (2)
A
- vertebrate egg type with a moderate amount of yolk
- embryo formed in amphibians
- large yolk causes blastocoel to be small and unevenly distributed (lies closer to the animal pole where there is less yolk)
- uneven cell size: larger cells near the vegetal pole where there is more yolk and smaller cells near the animal pole where there is less yolk
8
Q
microlecithal (4)
- yolk size
- vertebrate type
- blastocoel and cell size (2)
A
- vertebrate egg type with little yolk
- embryo formed in amphioxus or eutherian mammals
- due to small egg size, blastocoel takes up even distribution in the blastula
- more even cell sizes across the blastula
9
Q
macrolecithal (3)
- yolk size
- vertebrate type
- blastocoel and cell size
A
- vertebrate egg type with large yolk
- embryo formed in birds and many fish
- embryo initially develops as a flattened yolk disk sitting on top of the enormous yolk (yolk is not incorporated into the cell)
10
Q
egg
A
- female sex cell or gamete
11
Q
yolk (2)
A
- the nutritive material of an egg
- used as food by a developing, embryonic animal
12
Q
ectoderm (2)
A
- “outer skin”
- outer layer of cells
13
Q
mesoderm (2)
A
- “middle skin”
- middle layer of cells, sandwiched between the ectoderm and the endoderm
14
Q
endoderm (2)
A
- “inner skin”
- most inner layer of cells that line cavities within the egg
15
Q
epidermal ectoderm (2)
A
- surface ectoderm
- gives rise to tissues on the outer surface of the body
16
Q
notochord (3)
A
- arises from the medial region of the mesoderm
- a flexible rod that provides structural support
- signalling centre that directs cells
17
Q
neural plate ectoderm
A
- thickened plate of ectoderm cells that lie on the dorsal side of the egg
- formed in early neurulation/late gastrulation
18
Q
neural crest (3)
- development
- function
- fate
A
- cells that separate from the neural folds during neurulation
- most ectoderm cells are organized into large sheets, but neural crest cells can migrate independently through the embryo
- highly mobile cells will give rise to wide variety of structures in the adult
19
Q
neural tube (2)
- development
- fate
A
- formed when the neural folds fuse together to form a hollow tube during neurulation
- gives rise to the central nervous system, including the brain, spinal cord and parts of the eyes
20
Q
neurocoel (2)
- development
- fate
A
- hollow cavity in the neural tube that is formed during neurulation
- becomes the ventricles of the brain and the central canal of the spinal cord
21
Q
epimere mesoderm (3)
A
- “on top middle skin”: the mesoderm that is located near the dorsal portion of the embryo
- forms somites in the trunk region
- further differentiates into dermatome, myotome, and sclerotome
22
Q
mesomere mesoderm
A
- “middle middle skin”: the mesoderm that is located in the mid-section of the embryo
23
Q
hypomere mesoderm (2)
A
- “bottom middle skin”: mesoderm located near the ventral portion of the embryo
- solid sheet of hypomere mesoderm splints into two layers: somatic hypomere and splanchnic hypomere
24
Q
myotome mesoderm
A
- formed from epimere mesoderm
- gives rise to skeletal muscles
25
Q
dermatome mesoderm
A
- gives rise to dermis and connective tissue
- formed from epimere mesoderm
26
Q
sclerotome mesoderm
A
- formed from epimere mesoderm
- gives rise to vertebrae and ribs
27
Q
somatic mesoderm
A
- top layer of hypomere mesoderm
28
Q
splanchnic mesoderm
A
- bottom layer of hypomere mesoderm
29
Q
somatopleure (2)
A
- extra-embryonic ectoderm and somatic hypomere mesoderm
- form amnion and chorion
30
Q
splanchnopleure (2)
A
- extra-embryonic endoderm and splanchnic hypomere mesoderm
- form yolk sac and allantois
31
Q
homologous structures (2)
A
- features that share a common ancestry: structures arise from the same structure in their MCRA
- structures that are homologous may also be similar in function and appearance, but this is not true for all homologous structures
32
Q
phylogenetic tree (2)
A
- graphical representation of HYPOTHESIZED evolutionary relationships among taxa
- can use genetics, traits, behaviours, geography, etc to construct phylogenies
33
Q
convergent evolution
A
- produces similar characters that are NOT the result of inheritance from a common ancestor
34
Q
deuterostome development (2)
A
- during gastrulation, the blastopore will form in the posterior region of the embryo
- contrasts protostome development
35
Q
larva
A
- stage in the development of many animals, occurring after birth or hatching and before the adult form is reached
36
Q
dorsal hollow nerve cord (4)
- structure
- function
- development
- location
A
- hollow, fluid-filled structure
- forms the central nervous system (the brain and spinal cord)
- formed by invagination of ectoderm during neurulation
- located dorsal to the digestive tract, and
37
Q
notochord (4)
- structure
- development
- location
- function
A
- slender, flexible rod capable of lateral flexion (bending from side to side) but not axial compression (getting shorter from end to end)
- forms from mesoderm
- located dorsal to the digestive tract but ventral to the central nervous system
- provide support for locomotion by lateral undulation (propelling the body forward by bending the body from side to side)
38
Q
pharynx
A
- region of the digestive tract located just posterior to the mouth
39
Q
pharyngeal slits (2)
A
- openings in the walls of the pharynx
- arranged one after the other from anterior to posterior
40
Q
post-anal tail (3)
- structure
- location
- function
A
- muscular structure
- located posterior to the anus
- lateral undulation of the post-anal tail is often used for locomotion
41
Q
cranium (2)
A
- supports and protects the brain and other sensory structures
- composed of cartilage and/or bone.
42
Q
tunic (2)
A
- protective structure that is secreted by the epidermis and surrounds the body
- composed mostly of the protein tunicin and the polysaccharide cellulose
43
Q
myomeres (3)
- structure (2)
- development
A
- segmental blocks of skeletal muscle separated by layers of connective tissue - part of the body wall and are arranged in a series from anterior to posterior
- arise from the myotome epimere mesoderm of the somites
44
Q
endostyle (2)
A
- produces sticky mucus
- arises from ventral side of pharynx
45
Q
gonads (2)
A
- primary reproductive organs
- responsible for producing sperm and ova and secreting hormones
