Week 1 Objectives Flashcards
1
Q
What are the 3 subphylum of the phylum Chordata?
A
1) Cephalochordata
2) Urochordata
3) Vertebrata
2
Q
What are the major classes of subphylum Vertebrata?
A
1) Pisces
2) Tetrapods
3
Q
Major characteristics of Pisces (one of the major classes of subphylum Vertebrata)
A
All fish extinct and alive
4
Q
Characteristics of Amphibia (a class of tetrapods)
A
Amphibians and modern frogs, toads, salamanders, and caecilians
5
Q
Characteristics of Reptilia (a class of tetrapods)
A
Reptiles
6
Q
Characteristics of Aves (a class of tetrapods)
A
All birds -> This class is characterized by its feathers
7
Q
Characteristics of Mammalia ( a class of tetrapods)
A
All mammals _> classified by hair and mammary glands
8
Q
Characteristics of phylum Chordata that may be shared with members of the invertebrate phyla
A
Cephalization Complete digestive tract Bilateral symmetry Metamerism Triple lastly Eucoelomate body cavity Closed circulatory system Deuterostomy
9
Q
Chordate membership requirements:
A
Dorsal hollow nerve chord
Pharyngeal “gill” slits, arches, and pouches
A notochord
Post anal tail (optional)
10
Q
Major characteristics of vertebrates
A
Head
Trunk
Tail
Appendages
11
Q
Characteristics of Cephalochordata ( a subphylum of phylum Chordata)
A
Notochord from tip of tail to tip of head
Ex. Amphioxus
12
Q
Characteristics of Urochordata ( a subphylum of phylum Chordata)
A
Notochord only in tail
Ex. Sea squirts
13
Q
Characteristics of Vertebrata ( a subphylum of phyum Chordata)
A
Notochord goes to the middle of the head
Contains vertebral column
14
Q
Axes and panes used to subdivide the body of an organism displaying bilateral symmetry:
A
1) Cranal/Caudal
2) Dorsal/Ventral
3) Left/Right
15
Q
3 types of planes:
A
1) Sagittal plane
2) Frontal (coronal) plane
3) Transverse (cross-sectional) plane
16
Q
What is a frontal (coronal) plane?
A
Cranial/caudal & left/right
17
Q
What is a transverse (cross-sectional) plane?
A
Dorsal/ventral & left/right
18
Q
5 types of body movements:
A
1) Flexion
2) Extension
3) Abduction
4) Adduction
5) Rotation
19
Q
Explain Flexion:
A
Takes place in a Sagittal plane around left/right axis
Brings 2 parts closer together
20
Q
Explain Extension:
A
Sagittal plane around a left/right axis
Results in a straightening of a bent part
21
Q
Explain Abduction:
A
Frontal plane around a Sagittal axis
Movement away from midline
22
Q
Explain Adduction:
A
Frontal plane around a Sagittal axis
Movement toward a midline
23
Q
Explain Rotation:
A
Movement of body part around its long axis (cranial/caudal) in a transverse plane
24
Q
Characteristics of Acoelomates:
A
Lack a body cavity separating the somatic tube from the visceral tube
Doesn’t have true body cavity
25
3 types of organisms that can be recognized based on type of coelom or lack of coelom
1) Acoelomates
2) Pseudocoelomates
3) Eucoelomates
26
Characteristics of Pseudocoelomates:
Possess a cavity but is only partly derived from embryonic mesoderm
Have body cavity but not completely derived from embryonic mesoderm which is required to be a true coelom ate
27
Characteristics of Eucoelomates
Include most animals, including chordates
They possess a body cavity that is completely lend with derivatives of mesoderm
The only ones that have a true coelom
28
What is a mesentery?
Transition points where the visceral and parietal peritoneum join to form double layers
29
What are the linings associated with the splanchnic tube called?
Splanchnic or visceral peritoneum, visceral pleural, or viscera pericardium
30
What are the linings associated with the somatic tube called?
Somatic or parietal peritoneum, parietal pleural, or parietal pericardium
31
Characteristics of the somatic tube:
Outer tube interacts with external environment and consists of skin and skeletal musculature
Allows organism to detect changes in its external environment and to respond to those changes
32
Characteristics of the splanchnic tube:
Inner tube involved in metabolic functions
Includes gut tube and its derivatives such as the liver and pancreas
Responsible for nutrients brought into its lumen (cavity) from external sources and making the energy and building blocks (AA's, fatty acids, monosaccharides, etc) derived from these nutrients available for anabolic and catabolic metabolism
33
How many pairs of appendages do all modern vertebrates have?
2
34
Define pectoral appendages
Appendages toward cranial end of body
35
Define pelvic appendages:
Appendages closer to the caudal end of the body
36
Define mesoderm:
1 of 3 embryonic germ layers
Gives rise to skeletal framework
37
Who has an internal mesoderm skeleton?
Only vertebrates... This is what makes them unique from invertebrates. Invertebrates only contain an external skeleton (exoskeleton)
38
Define myomeres:
Segmentally arranged blocks of skeletal muscle
39
In mammals, what partitions off pleural cavities from other cavities?
A muscular diaphragm
40
What separates the pericardial cavity from the pleuroperitoneal cavities in fish, amphibians, and some reptiles?
Fibrous transverse septum
41
What separates the pericardial cavity from the pleuroperitoneal cavities in some reptiles and birds?
A tendinous oblique septum
42
Collectively, mesodermal linings of cavities are known as what?
Serous membranes
43
Define dorsal mesentery:
Suspends gut tube from dorsal roof of coelom
44
Define ventral mesentery:
Connects gut tube to ventral floor of coelom
45
Defense Metamerism:
Refers to segmentation
Describes subdivision of body into repeating anatomical units on either side of the midline extending from cranial to caudal end
46
Define Tripoblasty:
Embryonic term referring to origin of the body plan from 3 embryonic germ layers (ectoderm, endoderm, mesoderm)
47
Name the 3 embryonic germ layers
1) Ectoderm
2) Endoderm
3) Mesoderm
48
Define the germ layer: ectoderm
The outermost layer, gets rose to outer layer of integumentary and nervous systems
49
Define the embryonic germ layer: endoderm
Innermost layer, gives rise to gut tube and derivatives
50
Define the embryonic germ layer: mesoderm
Middle Ayer, givers rise to connective tissues, cartilage, bone, muscle and other related structures and tissues
51
Define Deuterostomy
Not unique to chordates
Origin of oral opening in relation to anal opening during embryonic development
In deuterostomes, the original embryonic opening (the blastopore) becomes the anus, and the mouth develops as a secondary opening
52
Define Cephalication:
Not unique to chordates
Development of definite head characterized by an accumulation of sense organs
53
Define ontogeny
Embryonic development of an organism as well as any developmental changes that occur after birth or hatching
54
Define Teleology:
Idea that characteristics develop bc they are needed
Ex. Birds needed to fly so they developed wings
55
Define Baer's Law
Features that develop earliest in ontogeny are oldest phylogenetically
Features that develop later in ontogeny are more recent in phylogenic development
Features common to all members of a major taxonomic group develop earlier in ontogeny than do subdivisions of the group
56
Define organic evolution (a component of the synthetic theory of evolution)
Based on fossil records, organisms today aren't the same as those from the past and vice versa
57
Define genetic diversity (a component of the synthetic theory of evolution)
All members of a population exhibit genetic variation (except identical twins)
58
What are sources of variability for genetic diversity?
Sexual reproduction (independent assortment and crossing over), recombination (fertilization), mutation
59
What are the components of the theory of natural selection (a component of the synthetic theory of evolution)
Genetic variability exists in sexually reproducing populations
Some members of a population are more fit for the environments than others -> these individuals have a better chance of survival and having fertile offspring (survival of the fittest) -> These genotype so will become more frequent in the population over many years
If the environment stays the same, the population achieves genetic equilibrium and evolution slows down or stops
60
Who published the theory of natural selection?
Charles Darwin and Alfred Wallace
61
Who is the author of acquired characteristics?
Jean Baptistery Lamarck
62
What are the components of acquired characteristics?
An organism may develop an atomic changes in response to specific pressures it encounters at any point during its life
These acquired characteristics may be passed on to offspring
63
Define Analogy
Similarity in function in structures in 2 or more species
Neither the anatomy nor the embryo logical development is similar
Ex. Wing of bird and wing of insect
64
Define analogous
Structures similar in function but different in anatomical structure
Not derived from common ancestors
65
Define Homology
Structural similarity uniquely evolved due to inheritance from a common ancestor or developed from a common embryonic
Function doesn't have to be similar
66
Define Homologous
Structures found in different organisms that are similar anatomically and in embryo development and may or may not be similar n function
Derived from common ancestor
67
Major differences between analogy and Homology
Analogy is not derived from common ancestor and Homology is
Analogy requires similarity in function and Homology does not
Homology requires similar structures and analogy does not
68
Define Homoplasy
Structural similarity between different organisms not due to inheritance from common ancestor
69
Define Parallelism
Independent development of similar characteristics in lineages that inherit from a common ancestor a potential for the trait but don't directly inherit them
Ex. Gerbil-rat and kangaroo come from common ancestor -> both jump and have bushy tail for balance
70
Define Convergence
Independent development of similar characteristics n 2 or more lineages even though they don't receive from the adaptations from a common ancestor
Ex. Dolphin and shark -> environment causes similarity
71
Define Paedomorphosis
Larval form does not metamorphose, larval form becomes the adult form and develops gonads and sexually mature
Ex. Amphioxus
72
Define Neoteny
A type of Paedomorphosis adult form retains 1 or more larval characteristic
Ex. External gills in salamanders
73
Explain how Paedomorphosis might be used to explain origin of vertebrates
Larval tunicate forms gave rise to cephalochordates and vertebrates (example of paedogenesis)
74
What geological period did vertebrates first appear?
Cambrian
75
What axis make up the sagittal plane?
The cranial/caudal & anterior/posterior
76
How does a pseudocoelomate differ from a eucoelomate?
Both posses body cavity but pseudocoelomates is only partly derived from embryonic mesoderm
77
What is a coelom?
Space separating somatic tube from splanchnic tube, lined by mesodermal derivatives associated with the 2 tubes
78
What is hypoxia like musculature?
Layers of skeletal muscle that form walls of body cavity as well as fish fins & tetrapod limbs
79
Vertebrate coeloms are divided into 2 subdivisions & mammals are divided into 3, what are these called?
Vertebrates: pericardial, pleuroperitoneal
Mammals: pericardial, pleura, peritoneal
80
What are the 3 main components of the synthetic theory of evolution?
- Organic evolution (organisms living today are not the same that lived in the past & vice versa)
- Genetic diversity (all members of a population demonstrate genetic variation)
- theory of natural selection (co-developed by Darwin & Wallace)
81
Which theory, authored by Lamarck, states that during its lifetime, an organism may develop anatomical changes in response to pressures it encounters & these traits may be passed to offspring?
Theory of acquired characteristics
82
Common ancestor of echinoderm and chordates were probably...
```
Sessile or semisessile
Deuterostomous
Coelomate
Bilaterally symmetric
Ciliated larval form
Lophophorate
```
83
What are the major anatomical characteristics of amphioxus?
Lacks cartilage and bone, has myomeres used for movements, cranial end consists of conspicuous tubular pharynx w/ pharyngeal slits on both sides. Mouth opens isn't pharynx & has an endostyle on floor of pharynx that secretes mucous which covers the inside of gill slits and traps food particles to bring to intestine.
84
Define a Clade:
Monophyletic group made up of an ancestor and all of its descendants
85
Define a paraphyletic group
Includes a common ancestor and some but not all of its descendents
86
Define a polyphyletic group
Includes descendants but not the common ancestor
87
Define synapomorphies
Derived characters that are shared by several lineages
88
Define a cladogram
A diagram that shows a sequential hypothetical evolutionary branching pattern of a group of Clare's
89
Define apomorphy
Derived character (a derived character is different from the ancestral condition)
90
List major characteristics of urochordates and compare the adult and larval forms.
(I.e. Tunicates/sea squirt)
- Adults- sessile bag of fluid, lack notochord and dorsal hollow nerve cord, but have well developed pharynx with gill slits. Has 2 short hoses (siphons).
- Larva-have all 3 chordate characteristics
91
List the 5 classes of fish
- Agnatha
- Acanthodii
- Placodermi
- Chondrichthyes
- Osteichthyes
92
Give examples and characteristics of of the class Agnatha
- Lamprey & hagfish
- Lacks jaws and paired appendages
- Oldest known vertebrates
- All extinct
- Devonian period
- 10 pairs of cranial nerves (we have 12)
- Dermal armor (possibly used for protection and phosphate storage but we don't know for sure)
93
Give examples and characteristics of of the class Acanthodii
- Climatius
| - streamlines body, large scales, most are freshwater
94
Give examples and characteristics of of the class Placdermi
- Coccosteus
| - Some are very large, they have a moveable head between head and trunk to be able to open mouth wider
95
Give examples and characteristics of of the class Chondrichthyes
- Sharks/rays
| - Cartilaginous, lack ability to form bone, large eggs, paired double nostrils
96
Give examples and characteristics of of the class Osteichthyes
- Lungfish/sturgeon/common fish
| - Can form bone
97
Compare the characteristics of the subclass ostracodermi with subclass cyclostomata
- Both lack jaws & paired appendages
- Ostracodermi have muscular pumping mechanisms, nasal openings and a pineal organ (photoreceptor) and dermal armor
- Cyclostomata has round mouth -> includes lamprey and hagfish
98
List 3 major developments that set gnathostomes apart from earlier fishes
- Development of jaws -> ingestion of food and presented of food allows for food storage
- paired appendages -> improved ability to pursue or escape
- buoyancy mechanisms (lungs/swimbladders) -> fish could control depth in water without having to swim continuously but sharks must swim to control depth and lack swim bladders!
99
List the major anatomical characteristic that distinguishes sarcopterygians from actinopterygians
-Fin anatomy: Sarcopterygians have lobe paired fins and Actinopterygians have ray fins
100
During which Paleozoic era did fishes appear?
Cambrian
101
Describe the significance of the major morhological development in the gnathostomes: development of jaws
can bite food into pieces, presence of stomach allows for food storage
102
List the 4 classes of tetrapods
- Amphibia
- reptilia
- Aves
- mammals
103
List an example and characteristics for Amphibians
- salamanders/frogs/toads
| - have pedicellate teeth, cyclindrical vertebral centra, 2 auditory ossicles
104
List an example and characteristics for Reptilians
- Lizards/crocs/turtles/dinos
- classification depends on holes (fenestrae) & intervening bony arches on back sides of skulls: anapsids, synapsids, diapsids, euryapsid
105
List an example and characteristics for Aves
- common bird
- "feathered dinosaurs"
- replaced bony tail with feathers, have reduces digits without claws, lack teeth
106
List an example and characteristics for Mammals
- humans/dogs,kangaroos
| - live birth, endothermy, hair/fur, mammary glands, 4 chambered hearts
107
What is the group of Devonian tetrapods presumed to have given rise to modern amphibians?
Temnospondyls
108
List the orders of moderns amphibians and their major characteristics
- caudates (urodeles): they have a tail
- anurans (frogs & toads): lack a tail
- apodans (caecilians): lack limbs
109
What are the 2 groups of anapsids? List the characteristics for the one that is considered the stem reptile for all other reptiles.
- Cotylosaurs: stem reptile-may have been several feet in length, had dermal armor, skulls laterally flattened, not skull openings behind orbits.
- Chelonia
110
What are the distinguishing features between the 2 groups of dinosaurs?
The pelvic girdle
- ornithischians: bird hipped
- saurischians: lizard hipped
111
What are the 3 sub groups of modern lepidosaurs & what is their skull type with regard to lateral, post orbital openings?
- sphenodon: true diapsid skull
- snakes- diapsid but lost both bars
- lizards- diapsid but lost lower bars
112
Why do dinosaurs form a paraphyletic group?
Because it includes the ancestor of birds and dinosaurs but doesn't include the actual birds
113
List reptilian characteristics found in early birds such as Archaeopteryx
- bony tail
- separate fingers with claws
- teeth
114
What are some theories on the origin of flight in birds?
- as a means of thermal insulation
- insect-catching net
- allowed for better pursuit of prey or escape from predation
- may have allowed early archosaurs to roost in trees at night
115
What was the earliest group of synapsids?
Pelycosaurs
116
What are the characteristics shared by mammals & advanced therapsids?
- Secondary palate of premaxillary, maxillary, & palatine bones
- pterygoid bones fused to brain case
- enlarged dentary bone
- differentiation of teeth
- considerable regional differentiation of ribs and vertebrae
- jaw articulation pattern
- legs pulled in
- ilium extended forward
- elongated sacrum
- feet well developed
117
What some mammalian characteristics
- live birth
- endothermy
- respiratory diaphragm
- four chambered heart with completely divided ventricle
- neocortex
- double occipital condyle
- mandible consisting of a singe bone
- bony secondary palate
- loss of interclavicle (except in egg laying)
- hair/fur
- possess mammary glands
118
What are the 3 groups of modern mammals and what separates them?
- monotremes-egg laying
- marsupials- pouched mammals
- placentals- placental births
119
Identify the earliest group of mammals & describe their dentition
Morganucodonts- heterodont with triconodont molars
120
```
Birds are now thought to be most closely related to which of the following groups of reptiles?
A) Pelycosaurs
B) Pterosaurs
C) Dinosaurs
D) Cotylosaurs
```
C) Dinosaurs
121
```
Which component of the synthetic theory of evolution was proposed jointly by Darwin and Wallace?
A) Organic evolution
B) Genetic Diversity
C)Paedogenesis
D) Natural Selection
```
D) Natural Selection
122
```
Which of the following characteristics s unique to chordates?
A) Coelom
B) Triploblasty
C) Deuterostomous
D) Dorsal hollow nerve cord
```
D) Dorsal hollow nerve cord
*All other animals are found in most other animals so they aren't unique to chordates*
123
```
The similar body shapes in the shark and the dolphin represent an evolutionary phenomenon referred to by which of the following terms?
A) Parallelism
B) Convergence
C) Paedogenesis
D) Neoteny
```
B) Convergence
124
The agnathans are the earliest known vertebrates. Which of the following would NOT be characteristic of agnathans?
A) Armor plates covering much of the body
B) Lack of jaws
C) Pineal opening
D) Paired fins
D) Paired fins
125
List the requirements for terrestrialism
- Dessication control
- Resistance to gravity
- Changes in organs for special senses
- Excretion of nitrogenous waste
- Changes in reproduction
126
Describe Dessication control (a requirement for terrestrialism):
- Amphibians are subject to Dessication when out of water for a long time and require aquatic environment for reproduction
- Amphibians depend on their skin for gas exchange so skin must be kept moist to allow diffusion of respiratory gasses and must be thin and well vascularized
- When deprived of water, the pituitary changes to secrete vasopressin affecting permeability of certain tissues and allows water that would otherwise be lost to enter tissue spaces and be retained
127
Explain resistance to gravity (a requirement for terrestrialism):
- Requires anatomical adaptations that resist the pull of gravity and provide the body with support
- These adaptations include more dorsal positioning of vertebral column, considerable development of the pectoral and pelvic girdles and limbs, attachment of pelvic girdle to vertebral column, reduction in axial musculature in favor of an increased mass and complexity of the limb musculature
- During evolution, vertebrae became interlocking bones and less flexible
128
List the organs that have been changed for special senses (a requirement of terrestrialism):
- Lateral line system
- Ear
- Eye
129
Describe the changes made to the lateral line system (part of a requirement for terrestrialism)
Well developed in most aquatic organisms and allows organisms to detect electromagnetic waves n the water and is used extensively to find pray (all organisms send out electromagnetic waves)
130
Describe the changes made to the ear (part of a requirement for terrestrialism):
The ear changed and became able to conduct sound waves in air rather than water
- Lagnea formed the cochlea
131
Describe the changes made to the eye (part of a requirement for terrestrialism):
Evolution of the cornea allowed for coarse adjustments, while the lens allowed for fine adjustment
132
Name the 3 classifications of eggs
- Microlecithal
- Mesolecithal
- Macrolecithal
133
List the 2 types of egg distribution:
- Isolecithal
| - Telolecithal
134
Describe Microlecithal eggs:
Eggs containing a very small amount of yolk
Ex. Mammalian eggs (except egg-laying mammals)
135
Describe Mesolecithal eggs:
Contain a moderate amount of yolk
Ex. Amphibian eggs
136
Describe Macrolecithal eggs:
Contain a large amount of yolk
Ex. Bird and reptilian eggs
137
Describe Isolecithal eggs:
Small amount of yolk distributed evenly throughout
**Only microlecithal eggs**
138
Describe Telolecithal eggs:
Yolk is concentrated toward one pole of the egg
- The end of the egg with yolk concentration is the vegetal pole
- The opposite end of the egg with yolk free cytoplasm is the animal pole
* *Mesolecithal or Macrolecithal eggs
139
List the steps in development of a frog embryo from 1st cleavage through gastrulation:
1) 1st cleavage
2) 2nd cleavage
3) 3rd cleavage
4) Blastulation
5) Gastrulation
140
Describe the 1st cleavage in the development of a frog embryo:
- Begins in animal pole and sows in vegetal pole
- Mitotic activity not accompanied by growth
- Subsequent growth will result in formation of embryonic germ layers and beginning formation of specialized tissues and organs
- Produces 2 daughter cells (blastomeres)
141
What types of eggs undergo holoblastic cleavage?
Microlecithal and Mesolecithal
142
What types of eggs undergo meroblastic/discoidal cleavage?
Macrolecithal
143
Describe the 2nd cleavage in the development of a frog embryo
- Begins before the first cleavage is complete
| - Results in 4 daughter cells equal in size with the same amount of yolk in each
144
Describe the 3rd cleavage in the development of a frog embryo
- Perpendicular to the first 2 cleavages
- Not equal and is pushed above the equator of embryo into animal pole
- Results in 8 cells: 4 relatively small and yolk free (micromeres) and 4 large and densely packed with yolk (micromeres)
- Results in solid ball of cells consisting of more and smaller cells at animal pole and fewer and larger yolk-filled cells at vegetal pole
145
Define the Blastulation stage of the development of a frog embryo
- Cells begin to separate to form an internal cavity (blastocoele)
- Because of interference of the yolk, the blastocoel is displaced toward the animal pole
146
What is the internal cavity formed during Blastulation called?
Blastocoel
147
Describe the Gastrulation stage of the development of a frog embryo:
Cell movements and folding of cell layers resulting in a rearranged hollow ball stage (gastrula)
- Gastrula resembles blastula, but consists of several layers of cells and the cavity (gastrocoel) isn't the original blastocoel (this is the beginning of germ layers and formation of tissues)
148
How are frog gastrula related to the vertebrate body plan?
The body plans are virtually the same
149
List the basic steps in the early cleavage and development of avian embryo:
1) 1st cleavage
2) 2nd cleavage
3) 3rd cleavage
4) 4th cleavage
5) Delamination
150
Describe the first cleavage n the development of avian embryo:
- Represented by a furrow in cytoplasm of cytoplasmic disc at the top of the animal pole
- Cleavage doesn't extend into yolk but separates outward and deeper as the yolk is converted not cytoplasm
151
Why does cleavage of reptiles and birds occur within a flattened disc (blastodisc) versus a ball?
Because the eggs of birds and reptiles are filled with lots of yolk, so cleavage is restricted to a very small area of the animal pole
152
Describe the 2nd cleavage in the development of avian embryo
- Perpendicular to the 1st
- Similar to cleavage pattern of amphibians
- Results in 4 equal-sized blastomeres whose cytoplasm is in contact with yolk underneath and with continuous cytoplasm on periphery
153
The Avian embryo is used to illustrate amniote embryo development. What is referred to as an amniote?
Reptiles, birds, and mammals
154
Describe the 3rd cleavage in the development of avian embryo:
Furrows lie parallel and on either side of the 1st cleavage
| - Results in 8 connected blastomeres
155
Describe the 4th cleavage in the development of avian embryo:
- A circular furrow that forms the periphery of the first 3 cleavages, creating 16 blastomeres
- Yolk underneath central blastomeres undergoes dissolution, creating sub germinal space
- At ~16-32 cell stage, multiple layers of blastomeres created
- At ~several 100 cell stage, cell mass = the blastoderm and consists of 2 cell populations
- Cells separate out forming upper and deeper layers
156
What happens at about 16-32 cell stage during the 4th cleavage of the development of avian embryo?
Cleavage furrows begin to appear parallel to the surface of the blastodisc, creating multiple layers of blastomeres
157
What happens at several hundred cell stage during the 4th cleavage in the development of avian embryo?
The cell mass is referred to as the blastoderm and consists of 2 cell populations
158
Name the 2 cell populations contained in the blastoderm created during the several hundred cell stage of the 4th cleavage in the development of avian embryo:
Small yolk free cells and larger cells with yolk granules
159
Name the 2 layers created when the cells separate out forming an upper layer of small cells and a deeper layer of large cells during the 4th cleavage in the development of avian embryo:
Layer of small cells = epiblast
| Layer of large cells = hypoblast
160
Describe the stage of Delamination during the development of avian embryo:
- Goes from 1 end to another, the initiation spot is the future posterior end
- Epiblast separates from the lower layer of hypoblast forming a small cavity between the 2 layers
- When complete, hypoblast sinks into subgerminal space, creating space between the epiblast and hypoblast
161
What is the difference between Amphibian embryo cleavage and avian embryo cleavage?
Amphibian embryos undergo holoblastic cleavage whereas avian embryos undergo discoid all cleavage
162
What is meant by holoblastic cleavage?
Cleavage passes entirely through the egg
163
Describe the basic steps of early development and cleavage of mammalian embryo:
- Mammalian eggs are Isolecithal
- Cleavage is holoblastic
- 1st - 3rd cleavage is the same as the amphibian egg: equal and perpendicular to each other
- After the 4th cleavage, cleavage becomes unequal
- At about 4.5 days of cleavage, human embryo consists of ~8 larger inner cells and ~99 smaller outer cells (inner cells form inner cell mass and outer cells form trophoblast layer)
164
What is the difference between avian embryo cleavage and mammalian embryo cleavage?
Avian embryo cleavage is discoidal and mammalian embryo cleavage is holoblastic
165
What is a cavity lined with mesoderm referred to as?
A coelom
166
At about 4.5 days of mammalian cleavage, there are 8 large inner cells and about 99 smaller outer cells, what do these 2 layers form?
- Inner cells for inner cell mass
| - Outer cells for trophoblast layer
167
What does a trophoblast do at implantation?
It attaches to the endometrium and forms a cytotrophoblast and a syncytiotrophoblast
168
What is the cytotrophoblast?
Layer on cells on inside of the blastocyst, separated by cell membranes. Gives rise to the chorion.
169
What is the syncytiotrophoblast?
It forms on the side of the blastocyst that initiated implantation. Consists of syncytium-cytoplasm and membrane fused into a common mass.
170
What does the syncytiotrophoblast do?
It erodes into the endometrium and forms cavities (trophoblast lacunae) that will become filled with maternal blood that provides nutrients and oxygen to the embryo
171
The cytotrophoblast and syncytiotrophoblast form to combine....
The placenta
172
What do cells from the inner cell mass form?
The embryo proper and additional membranes that surround and support the embryo (amnion, yolk sac, allantoic stalk)
173
What are some advantages for embryos developing in an aquatic environment?
- Carbon dioxide and oxygen diffuse readily between the embryo and the environment
- Nitrogenous waste products (usually ammonia) can be readily excreted
- desiccation is reduced
174
What are some disadvantages for embryos developing in a terrestrial environment?
- Keeping the cell membrane moist, a MUST if diffusion is to occur, becomes difficult
- Copious amounts of water to dilute the highly toxic ammonia waste products are not available
- Food for the embryo may not be readily available
175
What are the 4 extraembryonic membranes?
- Chorion
- Amnion
- Yolk sac
- Allantois
176
What embryonic germ layers constitute the chorion?
-Ectoderm and mesoderm
177
What embryonic germ layers constitute the amnion?
-ectoderm and mesoderm
178
What embryonic germ layers constitute the yolk sac?
Endoderm and mesoderm
179
What embryonic germ layers constitute the Allantois?
Endoderm and mesoderm
180
List the major functions of the vertebrate integument:
1) Protection
2) Coloration
3) Sensory reception
4) Excretion
5) Gas exchange
6) Water regulation
7) Temperature regulation
8) Food storage
9) Nourishments
10) Locomotion
181
Define the major function of the vertebrate integument: Protection
- protection against mechanical injury and invasion by foreign organisms and substances
182
Define the major function of the vertebrate integument: Coloration
- Protection through camouflage
- Provide warming signals
- Involved in sexual recognition
183
Define the major function of the vertebrate integument: Sensory reception
- Integument may be densely packed with receptors for touch, pressure, temperature, pain, and or electromagnetic detection
184
Define the major function of the vertebrate integument: Excretion
May be used to excrete excess salt (fishes) or nitrogenous waste products
185
Define the major function of the vertebrate integument: Gas exchange
- Many vertebrates can carry out respiratory gas exchange partly or entirely through the integument
- In amphioxus, gas exchange occurs almost exclusively through the integument -> gills are used for filter feeding
186
Define the major function of the vertebrate integument: Water regulation
Integument is very important in preventing excess water loss
187
Define the major function of the vertebrate integument: Temperature regulation
- Especially in terrestrial vertebrates and marine animals
- Feathers in birds and hairs in mammals assist in temperature regulation
- Dilation and contraction of cutaneous blood vessel and associated sweating are important thermoregulatory mechanisms
188
Define the major function of the vertebrate integument: food storage
- Among mammals and birds, the connective tissue blew the dermis (hypodermis) is a common site for the deposition of adipose (fat) tissue, which can be used both for insulation and for energy storage
189
Define the major function of the vertebrate integument: Nourishment
Mammary glands in mammals (integumentary derivatives) are an essential source of nutrition for infants
190
Define the major function of the vertebrate integument: locomotion
- Webbing in the feet of aquatic birds and frogs
- Wing feathers in birds
- Flight membranes in bats
- Specialized ventral epidermal scales (scutes) in snakes
191
List the characteristics and function of the Chorion:
- Surrounds the embryo as well as the other membranes
- Not directly attached to the embryo
- Lies just below the shell of eggs of reptiles and birds
- In mammals, it's involved in the formation of the placenta
- In reptiles and birds, it fuses with the allantois to form the chorioallantoic membrane, which is important for gas exchange
192
List the characteristics and function of the amnion:
- Surrounds the embryo proper except where the yolk sac and allantoic sac are attached
- Creates a fluid filled environment
- Important in protecting the embryo from desscation
193
List the characteristics and function of the yolk sac:
- Continuous with gut endoderm of the embryo
- In reptiles, birds, and egg-laying mammals, the yolk sac contains a massive amount of yolk necessary for nutrition for the developing embryos
- In other mammals, the yolk sac eventual disappears but serves as the preliminary site for the formation of blood cells and germ cells
194
List the characteristics and function of allantois:
- Projects from gut endoderm of embryo just caudal to yolk sac
- In reptiles and birds the allantois stores nitrogenous waste in the form of Uric acid and fuses to the chorion to form the chorioallantoic membrane necessary for gas exchange
- In mammals, only the proximal part of the allantois is retained, it forms the umbilical cord connecting the embryo to the placenta (chorion)
195
Describe the anatomy of the protochordate Integument:
- simple epithelium on a layer of simple gelatinous connective tissue
- no glands
- no dermis/epidermis
- ciliated in larvae
- covered by cuticle in adult
- Tunicates are enclosed by "tunic" secreted by epithelium and made of cellulose and a few cells
196
What is the histological structure of the vertebrate integument?
- epidermis (Stratified squamous epithelium): stratum corneum, stratum basale
Resting on...
-basement membrane: basal and reticular lamina
Resting on...
-dermis (dense irregular connective tissue): elastic fibers, collagen fibers, blood vessels, fibrocytes
197
What are the 2 basic types of glands?
- Exocrine: 1 or more excretory ducts, emptying contents into a body cavity or onto a surface
- endocrine: lack an excretory duct, emptying contents (hormones) into bloodstream
198
Glands can be considered.... (In regards to numbers of cells)
- Unicellular (goblet)
| - Multicellular
199
Name types of classifications of glands according to shape:
- Tubular
- Alveolar (acinar)
- Tubuloalveolar (-acinar or mixed)
200
What are the 2 types of secretion in glands?
Mucous or serous
201
What are the modes of secretion for glands?
- Merocrine (eccrine): cytoplasm and cell membrane and saved, most glands fall in this category
- Apocrine: apical membrane/cytoplasm is released with the product
- Holocrine: entire cell is destroyed and released with product
202
What types of glands are found in the epidermis of Agnathans?
Unicellular mucous
203
What types of glands are found in the epidermis of Chondrichthyes and Osteichthyes?
Unicellular and multicellular mucous
204
What is enamel secreted from and where is it derived?
Secreted by ameloblasts and derived from ectoderm
205
What is dentine secreted by and where is it derived?
Secreted by odontoblasts and derived from mesoderm
206
What is the difference in bone salts between enamel and dentine?
Enamel=90% bone salts (makes it very hard)
| Dentine=70% bone salts
207
What makes up an enameloid?
Amelogins and collagen
208
What is a ganoin?
Enamel arranged in layers
209
What is cosmine?
Radiating canals of dentine
210
What is osteodentine similar to?
Bone
211
What is pallial dentine?
Superficial layer of dentine
212
Describe placoderm scales
- Ancient armor, not in modern fishes, found in ostracoderms and placoderms
- Layers: Enamel-like substance, dentine, spongy bone, compact bone
213
Describe cosmoid scales
- Not in modern fishes, found in primitive crossopterygians and extinct dipnoans.
- Layers: (similar to placoderm, but dentine replaced by cosmine) Enamel-like substance, cosmine, spongy bone, compact bone
214
Describe placoid scales
- In sharks, reduced in rays, almost lost in ratfish.
| - Structure: bulk is made of dentine, covered by enameloid material, pulp cavity.
215
Describe palaeoniscoid scales
- Found in polypterus (chondrostean)
| - Layers: ganoin, cosmine, compact bone.
216
Describe lepidosteoid (ganoid) scales
- found in acanthodians, gar pikes, sturgeons
| - Layers: Ganoin, compact bone
217
Describe cycloid and ctenoid scales
- Cycloid found in bowfins (Amia), modern dipnoans, primitive teleosts (codfish)
- Ctenoid found in advanced teleosts
- Layers: Thin layer of compact bone on a thin layer of fibrous connective tissue
218
How have scales changed from early placoderm scales to modern scales?
-Many layers have been lost, scales have become much thinner and less productive
219
What was the major change that occurred in the integument of early amphibians that made it possible to exist in a terrestrial environment?
-Loss of armor for a keratinized (cornified) stratum corneum
220
Describe the stratum corneum beginning with amphibians
Outermost layer of integument. Consists of multiple layers of flattened cells joined by tight junctions. Cells in stratum corneum became keratinized beginning with amphibians
221
What is keratin?
A protein derivative of eleidin
222
What are keratinocytes?
Cells from stratum basale specialized to form keratin form keratin in their cytoplasm as they are pushed up from the stratum basale. Once they are separated from their oxygen supply and cytoplasm is replaced with keratin the cell is dead.
223
What is the most constant feature of the epidermis?
The stratum basale
224
What characteristics of the amphibians integument were important in the transition from an aquatic to terrestrial environment?
- Development of a true stratum corneum
- Highly vascularized dermis for gas exchange
- Numerous integumentary glands
225
What types of glands are associated with amphibian integument?
- Unicellular glands of Leydig-mucous glands in certain larval salamanders
- Multicellular mucous glands are common in amphibian integument. They secrete a water retaining layer of mucous on surface of epidermis.
- Multicellular granular (poison) glands are found in most amphibians and are especially well developed in toads and the poison dart frogs.
226
Describe the reptilian integument with emphasis on adaptations for terrestriality
- Stratum corneum is extremely well developed, reduces water loss and the necessity for many epidermal glands.
- Epidermal scales (derivative of stratum corneum) are actually folds in the stratum corneum rather than individual scales. Epidermis must be shed/molted for reptile to grow
227
Describe epidermal scales.
- Epidermal derivative
- interconnected by thin bridges of epidermis resulting in periodical shedding of entire continuous layer to allow for growth
- thickening and hardening of cornified epidermis results in formation of cornified scales (scutes)-- in snakes aid in locomotion
228
Describe dermal scales
- Dermal derivative and closely associated with bone
- In turtles, dermal scales contribute to the formation of carapace and plastron
- Overlapped and strengthened by epidermal scales
- Some lizards have "osteoderms"
- Crocs and sphenodon have gastralia (dermal bones on ventral body surface)
229
What are the major characteristics of avian integument?
- Relatively thin skin with well developed stratum corneum
- Reduced integumentary glands: Uropygial glands (base of tail) and modified oil glands associated with external ear opening
- Feathers are epidermal derivatives and are hallmark of avian integument (types- contour, down, filoplumes)
230
Describe the general structure of a contour feather.
- Shaft: base-calamus, longer distal part called rachis
- Barbs: extend out from rachis, equipped with hooks and barbules which interconnect
- Vanes: wide, flattened surface composed of rachis and barbs
231
What are the different types of feathers in birds? And what differentiates them?
- Contour feathers: feathers for flight attached to bone, all other attached to skin.
- Down feathers (plumules): usually evenly distributed, short calamus, lacks hooks and barbs, trap air, soft and fluffy
- Filoplumes: threadlike shaft, if it has a stiff rachis it is called a "bristle" (screens objects from nostrils, increase effective gape of mouth, form eyelashes)
232
What is a homeotherm?
Organism that can maintain relative constant body temperature in spite of variations in ambient temperature. Requires means of heat production and retention or loss of heat depending on the ambient temperature.
233
What is a poikilotherm?
Organism that takes on the surrounding ambient temperature. Can bask in the sun, press body against warm surface or seek shade to adjust.
234
What are some anatomical modifications that make homeothermy possible?
- Both feathers and hair (fur) trap air
- Air as insulator (helps retain body heat)
- High metabolic rate
- Sweating/panting
- Sending more or less blood to integument
235
Which vertebrate groups are considered homeotherms?
Birds and mammals
236
What are the general characteristics of The integument in mammals?
- Well developed epidermis and dermis
- stratum corneum
- Thick dermis
- Epidermal scales have generally disappeared from skin of mammals
237
What are some derivatives of mammalian integument?
- Hair (new derivative of stratum corneum)
- claws, antlers, hoofs, nails
- chromatophores
- Glands (mammary, sudoriferous, sebaceous, meibomian, glands of zeiss, ceruminous, scent)
238
What is meant by thick skin and thin skin?
Refers to the complexity, not the overall thickness of the skin
239
Where is thick skin found on the body?
-Found only on palms of hands and soles of feet
240
What are the layers of thick skin?
- Stratum basale (germinativum)
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
241
What are the characteristics of the stratum basale layer of thick skin?
- Deepest layer
- Single layer of cells held together by desmosomes
- High mitotic activity (produces stem cells that differentiate into keratinocytes)
242
What is a characteristic of the stratum granulosum layer in thin skin?
Makes up a whole layer in thick skin, but is comprised of only a few cels in thin skin
243
Is the stratum lucidum layer found in thick skin, thin skin, or both?
Only in thick skin
244
What are the characteristics of the stratum corneum layer in thick/thin skin?
- Multilayered (5-50), thicker in thick skin
| - Made of enucleated, flattened, dead keratinocytes
245
Describe the general histology of the dermis.
-Dermis is a dense, fibrous, irregular connective tissue layer beneath the epidermis. Derived from embryonic mesoderm. Has 2 layers:
Papillary (closest to epidermis)-loose connective tissue, separated from epidermis by basal lamina, network of fine elastic fibers and abundant capillaries.
Reticular layer- dense irregular connective tissue, includes fibrocytes, macrophages, and adipocytes.
-Hypodermis: Loose connective tissue that underlies dermis,technically not apart of skin, may contain fat cells.
246
What are the types of glands associated with the mammalian integument?
- Sudoriferous glands
- Sebaceous glands
- Mammary glands
- Meibomian glands
- Glands of Zeiss (eyelids)
- Ceruminous glands (ears)
- Scent glands
247
What are the characteristics and subtypes of Sudoriferous glands in mammals?
-Long, hollow, tubular glands. In humans, usually small and produce a thin watery secretion. In other mammals, tends to be larger and connected to hair follicles--secretes thick, milky, odoriferous fluid.
-Subtypes:
Merocrine sweat gland--watery secretion important in evaporative cooling and thermoregulation.
Apocrine sweat gland--associated with hair follicles in axiallary and pubic region, has thicker secretion that is acted on by bacteria
248
What are the characteristics of sebaceous glands in mammals?
Holocrine glands, in humans they are associated with hair follicles, keeps hair pliable and may provide role in waterproofing integument
249
What are the characteristics of mammary glands?
- Definitive characteristic in mammals,
- Histologically similar to Sudoriferous glands
- Both apocrine (fat) and merocrine (protein) secretion in humans
- Monotremes lack teats-glands open directly to body surface
- Human nipple is intermediate between version nipple of placentals and proliferation nipple of ungulates
250
What are the major characteristics (examples) of Cephalochordata?
Chephelochoradates or lancelets (ex. Amphioxus)
251
What are the major characteristics (examples) of Urochordata?
Ascidians (sea squirts), thaliaceans, and larvaceans, all of which are small marine organisms
252
What are the characteristics of the dorsal hollow nerve cord (a chordate membership requirement)?
- Arises embryo logically as a hollow tube located dorsal to the notochord
- The hollow nature of the embryonic neural tube is retained in all adult vertebrates in the form of hollow cavities within the brain (ventricles) and spinal cord (spinal canal)
- In many invertebrates, the nervous system consists of a solid ventral nerve cord
253
What are the characteristics of pharyngeal pouches (a chordate membership requirement)?
- The pouches may be open to the exterior as pharyngeal slits
- In many Chordates, such as fishes, these slits persist in the adult as gill slits
- Slits generally connect the interior of the pharynx with the external environment of the organism, but in the non-vertebrate Chordates (amphioxus), they open into a specialized chamber, the atrium, which then opens to the exterior via an opening called the atriopore
254
What are the major characteristics of the hypothetical ancestor of both echinoderms and chordates?
- sessile or semi sessile
- deuterostomous
- coelomate
- bilateral symmetry
- ciliated larval form
- lophophorates
- ciliary feeder
255
What are the major anatomical characteristics of an amphioxus?
- lack paired fins/limbs and jaws
- elongated, flattened, and tapered at both ends
- possess well developed notochord but no vertebral column
- nerve cord lies dorsal to notochord but doesn't have cranial enlargement
- lacks cartilage and bone
- "v"shaped myomeres flank notochord for swimming
- cranial end consists of conspicuous tubular pharynx with row of pharyngeal slits on either side
- mouth opens into pharynx
- gill slits open into atrium and atrium opens to exterior
- endostyle located on floor of pharynx secretes a thin film of mucous that covers inside of gill slits and traps food particles to bring to intestine
256
Where does the incurrent siphon in an adult sea squirt lead to?
Directly into a large, bag-like pharynx with numerous small filtration slits
257
What leads to the excurrent siphon in adult sea squirts? (Urochordate)
The intestine and atriopore
258
What is the outer wall in the sea squirt of the bag (tunic) made of?
-cellulose-like polysaccharide, tunic in, which is almost unheard of in the animal kingdom
259
Define pleisomorphies
Ancestral characters that are retained by the descendants of the ancestor
260
What are the 3 major classes of cartilage?
1) Hyaline
2) Elastic
3) Fibrocartilage
261
What is the function of cartilage?
- Compressible
- resists distortion
- absorbs shock in joints
- reduces friction in movable joints
- necessary for endochonral bone growth
- involved in bone fracture repair
262
Where is the hyaline cartilage located in mammals?
- External auditory meat us
- Ears, nose
- Movable joint surfaces
- Larynx
- Tracheal cartilages
- Bronchial cartilages
- Fetal long bones
- Articular ends of bones
263
Where is hyaline cartilage found in vertebrates of other than mammals?
- Entire skeletal system of Chondrichthyes
- Much of the skeletal system of some amphibians, especially limb girdles and distal limb components
**Reptilian skeletal system has much less cartilage in the adult skeleton than in amphibians**
264
Where is elastic cartilage found?
- auricle (pinna) of the ear
| - epiglottis
265
Where is Fibrocartilage found?
- Less movable joints: intervertebral discs, public symphysis
- Insertion of some tendons and ligaments
- Closely associated with dense connective tissue or hyaline
266
Where is fibro-elastic cartilage found?
In parts of the larynx
267
Describe the histology of hyaline cartilage:
- Most common type of cartilage, mostly a support cartilage
- Avascular
- Contains type 2 collagen fibers
- Surrounded by perichondrium
- Translucent, bluish gray to white
- Solid but flexible
- Chondrocytes are often found in cell groups (resulting from cell division)
- Growth patterns are appositional and interstitial
- Associated with highly movable joints
268
Cartilage tends to develop in regions of _____________; bone, however, tends to develop in regions of ___________
low oxygen; high oxygen
269
The Articular cartilage covering the ends of long bones lacks what? What does this mean?
Articular cartilage covering the ends of long bones lacks a perichondrium therefore it cannot be repaired or replaced if it is damaged and it deteriorates due to aging or pathological processes
270
Define appositional growth:
Growth that occurs by adding more material to the outside of existing material
271
Define interstitial growth:
Growth that occurs by inserting additional material into the existing substance
272
List the cartilage components:
- Cells: Chondrocytes and chondroblasts
| - Extracellular matrix: collagen fibers and amorphous ground substance
273
What are chondroblasts?
Cartilage-forming cells
274
What are Chondrocytes?
Cartilage-maintenance cells
275
The extracellular matrix of cartilage consists of collagen fibers, what type of collagen is this?
Mostly type 2 collagen
- Type 1 in Fibrocartilage
276
Describe the perichondrium (a characteristic of cartilage):
- Outer fibrous layer surrounding a mass of cartilage that contains fibroblasts
- Inner chondrogenic layer that gives rise to chondroblasts, which become Chondrocytes. The Chondrocyte is involved in the production of the collagen and Proteoglycans in the matrix
277
Describe Avascular (a characteristic of cartilage)
- Slow to heal
- Nurtients and oxygen are derived from blood vessels that surround the cartilage and must diffuse through the matrix to the cells
278
List the 3 components that are involved in the formation of cartilage and their function:
1) Chondroblasts: lay down cartilage matrix and become Chondrocytes
2) Chondrocytes: maintain cartilage matrix
3) Lacunae: pockets within the matrix where the chondroblasts and Chondrocytes are found
279
What makes up the hyaline cartilage matrix?
- chondroitin sulfate
- collagen fibers
- Proteoglycans
280
What are the 2 major components of bone matrix?
1) Osteoid - organic component
| 2) Hydroxyapatite - inorganic component, makes up 35% - 65% of the matrix
281
What are the 3 major categories of bone?
1) Woven bone - during bone development and repair
2) Compact bone - AKA lamellar bone
3) Spongy bone - AKA trabecular or cancellous bone
282
Describe the general histology of compact bone:
- Lacks cavities and forms a dense plate on the outside of long or flat bones
- Consists of Haversian lamellae which encircle a central blood vessel (and associated nerves) forming a Haversian system
- Osteocytes are found between the lamellae located in lacunae and are connected to each other and the Haversian canal via canaliculi
- Volkmann's canals run perpendicular to the Haversian canals and connect the Haversian Canada's to each other and to the surface of the bone
283
List the components of compact bone:
- fibrous periosteum
- osteopenic periosteum
- lacuna
- lamellae
- canaliculus
- Haversian canal
- Volkmann canal
Haversian system/osteopenic = lacuna, lamellae, canaliculus, Haversian canal
284
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Amphibian eggs contain a moderate amount of yolk that allows development to attain a free-swimming larval stage. Such eggs are best classified by which of the following terms?
A) Microlecithal
B) Mesolecithal
C) Macrolecithal
D) centrolecithal
```
B) Mesolecithal
**micro = little, macro = a lot, meso = moderate**
285
```
Cleavage in an amphibian egg passes through the entire egg, including the vegetal pole. Which of the following terms best describes this form of cleavage?
A) Meroblastic
B) Isoblastic
C) Holoblastic
D) Discoidal
```
C) Holoblastic
**Holo = whole, cleaves the whole egg**
286
```
During amphibian development, following Gastrulation, the roof of the gastrocoel is lined wth cells that form which of the following structures?
A) Notochord
B) Neural Plate
C) Gut endoderm
D) Future skeletal muscle
```
A) Notochord
287
Discoidal cleavage in the avian embryo in a 2 layered embryo is referred to as the blastoderm. This bilayer end mass of cells separates into an upper layer of yolk-free cells and a lower layer of yolk-filled cels. This separation process is referred to as Delamination. Which of the following characterizes Delamination?
A) Delamination separates the ectoderm from the mesoderm
B) The point at which Delamination begins marks the future posterior end of the embryo
C) The point at which Delamination begins marks the future anterior end of the embryo
D) Delamination creates the body coelom
B) The point at which Delamination begins marks the future posterior end of the embryo
288
In human development, the embryo at 4.5 days following fertilization consists of a ball of cells composed of 8 large cells surrounded by ~99 smaller cells. The outer cells form the trophoblast layer. What is the fate of the trophoblast layer?
A) Form the future skin ectoderm of the developing fetus
B) Form the future neural tube
C) Forms all the membrane surrounding the developing fetus
D) Forms the placenta
D) forms the placenta
289
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Which of the following extraembryonic membranes is composed of ectoderm and mesoderm and creates fluid-filled environment that protects the embryo from desiccation?
A) Amnion
B) Yolk sac
C) Allantois
D) Chorion
```
A) Amnion
290
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The vertebrate epidermis is classified as which of the following types of epithelium?
A) Simple squamous
B) Simple cuboidal
C) Stratified squamous
D) Simple columnar
```
C) Stratified squamous
291
Who developed the synthetic theory of evolution?
Earnst Meyer
292
Given that we have 2 groups of dinosaurs, what is the major anatomical feature that we use to divide the 2?
Pelvic girdle
293
What were the earliest mammals in the early Triassic period?
Morganucodont
294
What is the name of the earliest reptiles?
Catelosaurs
295
What is the name of the earliest amphibians?
Tennosphodyls
296
Where all does water pass through when moving through a sea squirt?
- pharyngeal slits into atrium
| - atrium via atriopore to excurent siphon
297
What were early Devonian tetrapods referred to? (Usually placed with amphibians)
-Labyrinthodonts
298
Which class co-existed with Devonian tetrapods and became extinct without giving rise to additional groups?
-Lepospondyls
299
What were some characteristics of early Devonian tetrapods?
- Probably aquatic
- lungs well developed and frequently used
- probably retained fish-like scales
- pineal body
- notch at back of skull for tympanic membrane
- rod like stapes attached to inside of tympanic membrane and inserted into a hole (fenestra ovalis) in side off braincase
300
What is the theory on the origin of birds?
-probably evolved from a bipedal archosaur (probably a saurischians)
301
Microlecithal eggs produce what kind of young?
"Miniature adults" must derive energy from development form nutrients obtained from maternal blood
302
Mesolecithal eggs produce what kind of young?
Larva
303
Macro lecithin eggs create what kind of young?
Adult-like
304
Following gastrulation in amphibian development, what happens to the surface layer of cells covering the gastrocoel?
Go through a folding process called neurulation resulting in formation of a tubular structure (neural tube) which will form the entire nervous system
305
What is the structure of hair?
- matrix of living, mitotically active tissue gives rise to shaft
- Multi-layered follicle (layers from bot epidermis and dermis)
- Vascularized dermal papilla (provides matrix with oxygen and nutrients)
- arrector plum muscle
306
What is the structure of claws, nails, and hoofs?
- essentially similar (compressed layers of stratum corneum)
- Keratin that makes up these structures and hair is "hard keratin" has a higher sulfur content than that of the epidermis
- Generic structure: ungis (hard dorsal plate), subungis (softer, innervated and vascularized ventral plate), matrix (modified layer of stratum germinativum found at the proximal end of the ungis),
307
In reference to what they walk on, what are horses, cattle, and related animals called and what kind of stance do they have?
- Ungulates
| - unguligrade stance
308
What kind of stance are members of the cat and dog family said to have?
Digitigrade stance
309
What type of stance are mammals such as humans and bears said to have?
Plantigrade stance
310
What is the structure of horns?
- Permanent structures
- Solid core of bone attached to frontal bone and covered by a thick layer of stratum corneum
- outer epidermis is solidly attached to the bony core
- outer epidermal layer can be shed seasonally but after death, the bony core remains attached but outer stratum corneum becomes detached
311
What is the structure of antlers?
- usually only found in males but reindeer is the exception
- bony outgrowth of the frontal bone
- growing bone is covered by layer of highly vascularized skin called "velvet"
- usually, just prior to breeding season, velvet loses blood supply and becomes dry and rubs off
- after breeding season, bony antlers fall off and are regrow not the following year
312
What are the major defining characteristics of mammals?
- Vertebrate
- homeothermy
- hair/fur
- mammary glands
313
What do many organisms use gill slits for?
Respiratory gas exchange, but the original function was for filter feeding
314
The pharynx is the cranial portion of what?
The gut tube
315
The primitive vertebrate pharynx was a device for...
Filtering food out of a respiratory water stream
316
What are the characteristics of the notochord (a chordate membership requirement)?
- In adult modern birds, reptiles, and mammals, the notochord is almost or completely obliterated
- It's remnants may be found in the intervertebral discs of mammals and reptiles as the nucleus pulposus.
- The notochord is also responsible for initiating the formation of the central nervous system, which is always located dorsal to the notochord
317
Name the 4 ways a gland can be classified:
1) Based on # of cells
2) Based on shape
3) Based on type of secretion
4) Based on mode of secretion
318
What is the earliest known subclass of fish to lack jaws and paired appendages?
Ostracodermi (subclass of class Agnatha)
319
A bees wings compared to a birds wings would be an example of what?
Analogy
320
Similar body shape between animals would be known as what?
Convergence
321
What is the similarity between amphioxus and sea squirts?
They take food and water in through their mouth which then goes through slits to be filtered
- Water goes into atrium and goes out atriapore
322
Describe the significance of the major morhological development in the gnathostomes: buoyancy mechanism
- Evolved form of lungs and swim bladder
- Fishes could control depth in water without having to swim continually
- Sharks must swim to control depth and lack swim bladders
323
Describe the significance of the major morhological development in the gnathostomes: paired appendages
Improved ability to pursue or escape
324
What are the steps in membrane bone formation?
- Bone laid down in fibrous (collagen) connective tissue matrix
- osteoblasts use collagen fibers as framework to deposit bone matrix
- bone formed within original mesenchyme has spongy texture spongy bone)
- periosteum may form on either side of spongy bone and lays down layers of compact bone on top of spongy bone (apposition all growth)
325
Where are membrane bones generally found?
-in bones that form walls of cavities such as cranial vault
326
Do membrane bones have attached tendons and ligaments? Why or why not?
No membrane bones do not form complex articulations and surfaces for tendons and ligaments
327
Which ways can membrane bones grow?
-appositionally in both thickness and diameter
328
Where does endochondral bone formation occur?
Within hyaline cartilage model
329
In endochondral bone formation, does cartilage turn into bone?
NO, it is REPLACED by bone
330
Endochondral bone can be remodeled by what types of cells?
-Osteoclasts and osteoblasts
331
What are the steps (in detail) of endochondral bone formation?
- Primary ossification center occurs in diaphysis of cartilage model
- chondrocytes become hypertrophic and secrete vascular endothelial growth factor
- blood vessels break through perichondrium, bringing in osteoprogenitor cells
- hypertrophic cartilage cells undergo apoptosis leaving behind thin strands of calcified matrix
- osteoblasts use calcified strands as substrates for deposition of osteoid
- osteoid is calcified
- simultaneously, cells derived from initial perichondrium begin to secrete osteoid appositionally
- perichondrium now = periosteum
- secondary ossification center occurs in epiphyses
- Epiphyses and diaphysis are separated initially by epiphyseal plate (growth plate) (contains reserve zone, proliferative zone, hypertrophic zone, and vascular invasion zone)
- Osteoblasts break down bone in center of diaphysis forming medullary cavity
- more cartilage continually added to distal end of epiphyseal plate
- cartilage at proximal end of epiphyseal plate is replaced by bone
- bone increases in length
- when cartilage in plate is overtaken by bone replacement, growth stops and epiphysis fuses to diaphysis
- Cartilage at either end of bone remains as articular cartilage
332
What is the epiphyseal plate made of?
Hyaline cartilage
333
What is another name for the epiphyseal plate and what four zones does it contain?
- growth plate
- Reserve zone
- proliferative zone
- hypertrophic zone
- vascular invasion zone
334
Cartilage at which end of the epiphyseal plate is replaced by bone in endochondral bone formation?
-proximal end
335
Where does the secondary ossification zone occur in endochondral bone formation?
In the epiphyses
336
The epiphyseal plate initially separates what?
The epiphyses and the diaphyses
337
Osteoclasts break down bone where to form the medullary cavity in endochondral bone formation?
-diaphyses
338
In endochondral bone formation, when blood vessels break through perichondrium, what type of cells do they bring in?
Osteoprogenitor cells
339
Where do the strands of calcified matrix that are used as substrates for deposition of osteoid by osteoblasts in endochondral bone formation come from?
They are left behind when hypertrophic cartilage cells undergo apoptosis
340
What type of cells, in endochondral bone formation, secrete vascular endothelial growth factor?
-hypertrophic chondrocytes
341
What is a diaphysis?
The shaft of long bone
342
What is epiphysis?
The ends of long bones
343
In endochondral bone formation, how is the network of cartilage matrix calcified?
By deposition of calcium salts
344
```
In the anatomical position, which of the following motion pairs occurs in a coronal plane (aka frontal plane) around an anterior/posterior axis?
A) Circumduction
B) Outward rotation-inward rotation
C) Abduction-Adduction
D) Flexion-extension
```
C) Abduction-Adduction
345
```
Which of the following classes of fishes includes the oldest known vertebrates as well as all extinct forms? Members of this group are characterized among other things by lack of jaws and paired appendages.
A) Placoderms
B) Ostracoderms
C) Osteichthyes
D) Sarcopterygians
```
B) Ostracoderms
346
```
Vertebrates first appeared in the fossil record during which of the following periods?
A) Cambrian
B) Carboniferous
C) Permian
D) Jurassic
```
A) Cambrian
347
```
Destruction of bone matrix during bone growth and remodeling or for repair is carried out by which of the following cells?
A) Osteocytes
B) Osteoblasts
C) Osteoclasts
D) Fibroclasts
```
C) Osteoclasts
348
```
Which of the following is unique to vertebrates?
A) Bilateral symmetry
B) Notochord
C) True Coelom
D) Vertebral Column
```
D) Vertebral column
349
```
A respiratory diaphragm, four-chambered heart with completely divided ventricle, neocortex, double occipital condolences, mandible consisting of a single bone (dentary) and a bony secondary palate are all characteristic of which of the following vertebrate groups?
A) Amphibians
B) Reptiles
C) Mammals
D) Dinosaurs
```
C) Mammals
350
```
In compact bone, the living cells that deposit and maintain the bone matrix depend on a system of tiny canals that bring oxygen and nutrients. These canals that interconnect the spaces occupied by the bone cells are referred to by which of the following terms?
A) Volkmann canals
B) Haversian canals
C) Canaliculi
D) Irrigation canals
```
C) Canaliculi
351
```
Cattle, deer, sheep and related mammals share a common characteristic related to the part of the foot that contacts the ground during standing and running. This is equivalent to the human toe nail and is referred to by which of the following terms?
A) Matrix
B) Frog
C) Ungis
D) Subungis
```
C) Ungis
