Quiz 2 Flashcards
1
Q
Hepatic Portal Vein
A
Large vein that lies in the gastrohepatoduodenal ligament
Formed from the union of the gastric, pancreaticomesenteric and lienomesenteric veins near the top of the dorsal lobe of the pancreas
2
Q
Gastric Vein
A
Accompanies gastric artery onto the dorsal and ventral surfaces of the stomach
3
Q
Lienomesenteric Vein
A
Extends along the dorsal lobe of the pancreas
Formed by confluence of the posterior lienogastric vein and posterior intestinal vein
4
Q
Posterior lienogastric vein
A
Vein that comes from the spleen and posterior part of the stomach
5
Q
Posterior Intestinal Vein
A
Arises from the posterior part of the intestine
6
Q
Pancreaticomesenteric Vein
A
Accompanies the pancreaticomesenteric artery to the beginning of the intestine, where it is formed by others such as the anterior intestinal vein and the anterior lienogastric vein
7
Q
Anterior Intestinal Vein
A
Extends parallel to the anterior intestinal artery
8
Q
Anterior Lienogastric Vein
A
Comes from the spleen and pyloric regions of the stomach
9
Q
Caudal Vein
A
Passes anteriorly through the hemal arches of the caudal vertebrae
10
Q
Afferent Renal Veins
A
Branch from the renal portal veins to carry blood to the kidneys
11
Q
Anterior Cardinal Sinus
A
Large vein that lies dorsal to the pharyngobranchial cartilages
Receives vessels that drain the eye, brain, head
12
Q
Orbital Sinus
A
Surrounds the eye and transports blood to the anterior cardinal sinus
13
Q
Inferior Jugular Vein
A
Thin vessel that drains the floor of the branchial region
14
Q
Hyoidean Sinus
A
Connects the anterior cardinal sinus and inferior jugular vein on either side of the head
Lies along the posterior surface of the hyoid arch
15
Q
Hepatic Vein/Sinus
A
Collects blood from the liver and opens into the posterior wall of the sinus venosus
16
Q
Common Cardinal Vein
A
Receives blood from the main vessels (except the liver), passing it back into the posterolateral corners of the sinus venosus
17
Q
Subclavian Vein
A
Enters the common cardinal vein just lateral to the entrance of the inferior jugular
18
Q
Posterior Cardinal Sinus
A
Large space lying dorsolateral to the esophagus, bounded by a thin-walled membrane
19
Q
Posterior Cardinal Vein
A
Vein that lies lateral to the dorsal aorta
20
Q
Efferent Renal Veins
A
Collect blood from kidneys and intersegmental veins that drain blood from body wall
21
Q
Lateral Abdominal Vein
A
Extends along the inside of the ventrolateral body wall on each side
Formed from confluence of cloacal vein and femoral vein
22
Q
Cloacal Vein
A
Vein that drains blood from the cloaca
23
Q
Femoral Vein
A
Drains blood from the pelvic fin
24
Q
Subscapular Vein
A
Extends parallel to the subclavian artery
25
Brachial Vein
Lies on the medial surface of the pectoral fin along with the brachial artery
26
Kidneys
Long, narrow structures on either side of the dorsal aorta on the roof of the body ccavity
27
Testes
Paired, elongated gonads of the male that lie dorsal to the liver in the pleuroperitoneal cavity
28
Ovaries
Paired, elongated gonads of the female that lie dorsal to the liver
29
Caudal Ligament
Between the posterior ends of the kidneys, arising from the vertebrae and passing to the tail
30
Epididymis
Most anterior part of the kidney in males, includes tubules that help transport sperm
31
Leydig's Gland
Middle third of the kidney in males that house tubules that make secretions to help transport sperm
32
Mesorchium
Mesentery that supports the testes and suspends them from the body cavity
33
Ductuli Efferentes
Small tubules in the anterior part of the mesorchium that extend from the testis to tubules in the epididymis
34
Archinephric Duct
Tightly convoluted, embedded in the ventral surface of the kidney (mature male)
Nearly straight in immature male, resembles oviduct
35
Sperm Sac
On ventral surface of seminal vesicle
Anteriorly blindly ending pouch
36
Accessory Urinary Duct
Thin duct that carries urine to the urogenital sinus
Extends along the medial margin of the kidney
37
Siphon
Lies just deep to the skin on the ventral surface of the pelvic fin
38
Mesovarium
Mesentery that suspends the ovaries from the body wall
39
Oviduct
Lies on the ventral surface of each kidney
Narrow, unsupported by mesentery in immature
Larger and supported in adult
40
Mesotubarium
Mesentery that supports the oviduct in adult females
41
Ostium Tubae
Opening of the left and right oviducts in the free edge of the falciform ligament
42
Nidamental Gland
Swelling of the oviduct dorsal to the ovary
| Secretes a thin membrane around groups of eggs as they pass to the oviduct; where eggs are fertilized
43
Uterus
Enlargement of the oviduct that occurs posteriorly
| Contains developing pups
44
Ampullae of Lorenzini
Modified parts of the lateral line system
| Series of tube-like structures just below and parallel to the skin
45
Lateral Line Canal
Extends midlaterally along the length of the body and into the tail
Lies within the skin and leads to other canals in the head
46
Olfactory Sacs
Function in olfaction (duh)
Has lateral incurrent and medial excurrent nares
Has lamellae within on which sensory receptors lie
47
Superficial Opthalmic Nerve
Passes anteroposteriorly along the dorsomedial wall of the orbit
48
Oblique Muscles (2)
Dorsal & Ventral
| Pass from the anteromedial wall of the orbit and attach dorsally and ventralls
49
Rectus Muscles (4)
Lateral, medial, dorsal, ventral
Radiate toward the eyeball from the posteromedial wall of the orbit
- Lateral attaches to posterior surface
- Medial attaches to medial/anterior surface
- Dorsal attaches to the top- Ventral
50
Deep Opthalmic Nerve
Thin strand that passes anteroposteriorly through the orbit and adheres to the medial surface of the eye
51
Optic Nerve
Extends from the medial wall of the orbit, laterally to the eyeball
52
Infraorbital Nerve
Passes anteriorly and slightly ventrally in the orbit
| Nearly as wide as any of the extrinsic muscles
53
Preorbitalis
Muscle that passes anteromedially across the floor of the orbit
54
Oculomotor Nerve
Passes ventrally and around the margin of the ventral rectus
55
Abducens Nerve
Innervates the lateral rectus
56
Trochlear Nerve
Passes into the dorsal oblique
57
Mandibular Nerve
Lies on the posterior wall of the orbit, posterior to lateral rectus, extends laterally
58
Cornea
Lateral portion of the eyeball, transparent
59
Sclera
Remainder of the eyeball, cartilaginous
60
Iris
Pigmented structure of the eyeball visible through the cornea, with circular pupil at centre
- Modified vascular tunic
- Contains intrinsic musculature that allows control over the size of the pupil
61
Lens
Hard spherical structure within the eye
62
Choroid
Dark pigmented layer internal to the sclera
63
Suprachoroidea
Vascular tissue between the choroid and sclera on the medial wall of the eye where the pedicle attaches
64
Ciliary Body
Holds the lens in place
| Contains intrinsic musculature to help control shape of the lens
65
Retina
Light tissue internal to the choroid
| Light sensitive, contains photoreceptors responsible for absorbing light
66
Vitreous Chamber
Large cavity of the eyeball medial to the lens
67
Vitreous Humor
Gelatinous mass in the vitreous chamber, helps maintain eyeball's shape and holds retina in place
68
Anterior/Posterior Chamber
Divisions of the cavity lateral to the lens, subdivided by the iris
69
Aqueous Humor
Watery fluid that fills the anterior and posterior chamber
70
Membranous Labyrinth
Series of ducts and sacs in the inner ear
71
Cartilaginous Labyrinth
Series of canals and chambers that contain the membranous labyrinth
72
Anterior/posterior Semicircular Duct
Vertically oriented ducts within the membranous labyrinth
73
Lateral Semicircular Duct
Horizontally oriented duct within the membranous labyrinth
74
Sacculus
Large, triangular sac-like structure that extends between the vertical ducts and medial to the lateral duct
75
Endolymphatic Duct
Extends dorsally from the sacculus and reaches the exterior surface of the head through the endolymphatic pores
76
Anterior/Posterior Utriculi
Closely associated with the sacculus, communicates with it through small openings
- Anterior attaches to anterior and lateral semicircular ducts
- Posterior attaches to posterior semicircular duct
77
Lagena
Posteroventral extension of the sacculus
78
Ampullae
Little bulbs that occur at the ends of ducts in the inner ear
79
Epiphysis
Extends dorsally from the posterior side of the epithalamus to the epiphyseal foramen
80
Telencephalon
Most anterior portion of the brain
Contains:
- Olfactory bulbs
- Olfactory tracts
- Cerebrum
81
Olfactory Bulbs
Telencephalon
Bulbs at the anterior end of the olfactory tracts, attach to the olfactory sacs anteriorly
82
Olfactory Tracts
Telencephalon
Narrow tracts that attach the olfactory bulbs to the cerebrum
83
Cerebral Hemispheres
Telencephalon
Extend from the posterior sides of the olfactory tracts, a little ways before going ventrally on the brain
84
Cerebrum
Two cerebral hemispheres together
85
Diencephalon
Second portion of the brain, posterior to the telencephalon and anterior to the mesencephalonIncludes:
- Epithalamus
- Thalamus
- Hypothalamus
86
Epithalamus
Roof of the diencephalon
87
Thalamus
Side of the diencephalon
88
Hypothalamus
Floor of the diencephalon
89
Telea Choroidea
Diencephalon
Thin, vascular tissue that forms the epithalamus
Attaches anteriorly to the cerebrum
90
Third ventricle
Diencephalon
Cavity within the diencephalon that contains various vascular structures
91
Foramen of Monro
Diencephalon
Foramen through which the third ventricle leads to the left and right lateral ventricles
92
Lateral Ventricles
Diencephalon
Left & rightLie respectively in the left and right cerebral hemispheres
93
Mesencephalon
Third portion of the brain, posterior to the diencephalon and anterior to the metencephalon
94
Optic Lobes
Mesencephalon
Paired, rounded
95
Cerebellum
Metencephalon
Large, main structure of metencephalon
Partially overhangs optic lobes anteriorly and myelencephalon posteriorly
96
Auricles
Metencephalon, cerebellum
Project anterolaterally from the posterior end of the metencephalon
97
Metencephalon
Fourth portion of the brain, posterior to mesencephalon and anterior to myelencephalon
98
Myelencephalon
Most posterior part of the brain, largely tubular
99
Medulla Oblongata
Myelencephalon
Posterior part of the brain that narrows into the spinal cord
- Roof covered by telea choroidea
100
Fourth ventricle
Myelencephalon
Cavity of the medulla, revealed by removing the telea choroidea; has various ridges and grooves
101
Somatic Motor Columns
Myelencephalon
Two large midventral ridges on either side of the midventral groove within the fourth ventricle
102
Visceral Sensory Columns
Large longitudinal ridges lateral to the somatic motor columns (divided by a depression)
103
Visceral motor columns
Small columns between the somatic motor columns and visceral sensory columns
104
Somatic sensory column
Large longitudinal ridge dorsal to each visceral sensory column
Surface has form of small, bead-like swellings
105
Acousticolateral Area
Anterior enlargement of the somatic sensory column
106
Terminal Nerve
Most anterior cranial nerve
Passes along the medial side of the olfactory tract
107
Olfactory Nerve
Second most anterior nerve
Pass from olfactory sac into olfactory bulb
108
Oculomotor Nerve
Arises from ventral surface of the mesencephalon and branches to innervate ventral oblique and dorsal/ventral/medial rectus
109
Trochlear Nerve
Extends anterolaterally from the dorsal surface of the mesencephalon
Innervates dorsal oblique
110
Abducens Nerve
Arises from ventral surface of the medulla
Passes anterolaterally and innervates the lateral rectus (found on ventral side)
111
Trigeminal Nerve
Arises from the anterior part of the medulla, just behind the auricles of the cerebellum
Large nerve that divides into four branches on emerging into the orbit - superficial opthalmic, deep opthalmic, mandibular, maxillary
112
Superficial Opthalmic Branch
Branch of the trigeminal nerve
Most dorsal of the branches, passes just ventral to the dorsal margin of the orbit
113
Deep Opthalmic Branch
Branch of the trigeminal nerve
Passes through orbit and adheres to dorsoventral surface of eyeball
114
Mandibular Branch
Branch of trigeminal nerve
Extends laterally along posterior wall of orbit, almost directly posterior to lateral rectus
115
Maxillary Branch
Branch of trigeminal nerve
Contributes to infraorbital nerve
116
Infraorbital Nerve
Large nerve passing along the floor of the orbit and crossing the preorbitalis
117
Facial Nerve
Arises from the anterior part of the medulla, just behind the auricles of the cerebellum
Two branches: hyomandibular and palatine
118
Hyomandibular Branch
Branch of facial nerve
Forms hyomandibular nerve along with AVLLN
Passes over levator hyomandibulae
Has geniculate ganglion, swelling near origin
119
Palatine Branch
Branch of facial nerve
Participates in the innervation of the lining of the oral cavity
120
Statoacoustic Nerve
Arises from the anterior part of the medulla, just behind the auricles of the cerebellum
Short nerve that innervates the ear
121
Preotic Lateral Line Nerves
Arise from the anterior part of the medulla, just behind the auricles of the cerebellum
- Anterodorsal Lateral Line Nerve (ADLLN)
- Anteroventral Lateral Line Nerve (AVLLN)
- Otic Lateral Line Nerve (OLLN)
122
Glossopharyngeal Nerve
Arises posterior to the statoacoustic nerve
Extends through floor of otic capsule to first pharyngeal slit
Swelling, petrosal ganglion before emerges from the capsule
Divides into posttrematic and pretrematic branches
123
Postotic Lateral Line Nerves
Arise from the brain between the glossopharyngeal and vagus nerves
- Middle Lateral Line Nerve (MLLN)
- Supratemporal Lateral Line Nerve (STLLN)
- Posterior Lateral Line Nerve (PLLN)
124
Vagus nerve
Mainly innervates pharyngeal slits 2-5 and viscera
Arises from medulla just posterior to glossopharyngeal, clumped with postotic lateral line nerves
Has visceral and intestinal branches
125
Branchial Branches
Branches of the vagus nerve, visceral branch
Branches that innervate pharyngeal slits 2-5-
Subdivides into pretrematic, posttrematic and pharyngeal branches
126
Hypobranchial Nerve
Crosses the intestinal branch of the vagus nerve, innervates hypobranchial musculature
127
Occipital Nerve
Union of slender roots posterior to the vagus nerve, partially merges with vagus
128
Hypophysis
Ventral extension of the brain, just behind the optic nerves
129
Optic Chiasm
Where the optic nerves cross over to the opposite side of the brain toward the anterior part of the hypothalamus
130
Infundibulum
Forms the remainder of the hypothalamus not covered by optic nerve
131
Vascular Sac
Continuation of the infundibulum posterior to each inferior lobe
132
Central Canal
Narrow canal within the spinal cord, filled with cerebrospinal fluid in life (as are the ventricles)
133
Optic ventricle
Extension of the third ventricle into the optic lobes and hypophysis
134
Cerebellar ventricle
Continuation of the fourth ventricle into the cerebellum
135
Cerebellar Aqueduct
Narrow canal that connects the third and fourth ventricles
136
Synapsida
Clade within Amniota
Include Mammalia and fossil relatives
Characterized by synapsid skull type
137
Therapsida
Clade within Synapsida
| Contains mammals and relatives
138
Non-mammalian synapsids
Usually referred to as "mammal-like reptiles"
| - More reptile-like in general way of living
139
Mammalian Features
- Mammary glands
- Hair
- Muscular diaphragm
- Single dentary forms mandible
- 3 middle ear ossicles
- Complex tooth form
- Body above legs
140
Mammals vs. Reptiles
Mammal
- Single dentary forms each lower jaw half
- Three middle ear ossicles: malleus, incus, stapes
- Squamosal-dentary jaw joint
Reptile
- Several bones form each lower jaw half
- One middle ear ossicle: stapes
- Quadrate-articular jaw joint
In mammals, articular and quadrate have become the malleus and incus, respectively; angular has become ectotympanic
- At transitional stages, squamosal, quadrate, articular and dentary all involved in joint
141
Pelycosaur
Early synapsid
| Not a natural group
142
Monotremata
```
Monotremes
Only three species: 1 platypus, 2 echidnas
- Retain cloaca
- Lack nipples
- Lay eggs w/ leathery shell
```
143
Theria
Includes Marsupialia & Eutheria
144
Marsupialia
- Occur in Australia & South America
- Females of many have pouch
- Young born at early stage, complete development in pouch
- Have placenta, but usually non-vascularized yolk sac placenta
145
Eutheria
- Much more numerous and widespread than marsupials and monotremes
- All have chorioallantoic placenta
- Young remain in utero to become more advanced before birth
146
Embrology
Processes involved in the early development of an individual
- Important for animal (obvi)
- Characters can be used to study phylogeny
- Helps understand basic organization of systems
147
Early embryological processes
Vary greatly among vertebrates
All lead to similar end, but get there differently
Differences mainly due to egg type, amount of yolk
- Microlecithal
- Mesolecithal
- Macrolecithal
148
Microlecithal
Egg with little yolk
149
Mesolecithal
Egg with moderate amount of yolk
150
Macrolecithal
Egg with a lot of yolk
151
Vegetal pole
Lower hemisphere of an egg that contains yolk
152
Animal pole
Hemisphere of egg that is less yolky and contains developing embryo
153
Microlecithal development
1. Two vertical divisions followed by a horizontal
2. Divisions continue to happen
3. Egg becomes spherical (blastula), 1 cell thick in amphioxus
154
Blastula
Spherical mass of cells with central cavity in developing egg
155
Blastocoele
Central cavity within a blastula
156
Mesolecithal development
- Initial cell divisions not equal
- Cells of animal pole smaller
- Blastula that is several cells thick
- Blastocoele displaced to animal pole
157
Macrolecithal development
- Only small bit of protoplasm at top
- Cell division occurs within small cap
- Blastula is plate of cells at animal pole
- Blastula separated from yolk by blastocoele
158
Mammalian development
- Embryo develops in uterus instead of egg
- Division forms spherical mass that appears superficially like microlecithal but is not
- Outer structure is trophoblast, within which there is a cell mass at animal pole
159
Trophoblast
Spherical structure of early mammalian embryo
160
Gastrulization
```
Division and migration of cells to produce a gastrula
Leads to 3 primary germ layers:
- Ectoderm
- Mesoderm
- Endoderm
```
161
Microlecithal Gastrulization
- Vegetal pole of blastula folds into cup-like structure by rolling cells into blastocoele
- Cells of animal
162
Gastrocoele
A.K.A. archenteron
Infolding of the gastrula after blastula has rolled into the blastocoele
163
Blastopore
Entrance into the gastrocoele
164
Ectoderm
Formed from the cells of the animal pole
Create outer layer of skin, nervous system, lining of oral cavity
- Covers neurectoderm/neural tube
165
Endoderm
Formed from the cells of the vegetal pole
Create digestive tract and visceral derivatives; liver, pancreas, lining of lungs, digestive tract and urinary bladder
- Expands dorsomedially and surrounds archenteron
166
Neurectoderm
Dorsal middle of ectoderm
Becomes brain, spinal cord, nerves and parts of eye
- Inpockets and is covered by ectoderm
- Neural crest cells begin to migrate
167
Mesoderm
```
Formed between the ectoderm and endoderm
Create skeleton, muscle, circulatory system
Two kinds:
- Chordamesoderm
- Lateral mesoderm
```
168
Chordamesoderm
Mesoderm along the dorsal midline, forms the notochord
169
Lateral mesoderm
```
Mesoderm except along dorsal midline
Forms the organs and stuff
- Expands laterodorsally on either side
- Subdivides forming the coelom
- Subdivides dorsoventrally into epimere, mesomere, hypomere; coelom enlarges
```
170
Neurogenic placodes
Clusters of cells in the neurectoderm that swell to become different structures
- Become various sensory head structures
171
Neural crest cells
Cells in the neurectoderm that migrate to other parts of the body
- Become visceral skeleton inc. jaws, meninges, etc.
172
Coelom
Cavity within the lateral mesoderm
173
Epimere
Division of lateral mesoderm
| - Subdivides lateromedially into dermatome, myotome, sclerotome
174
Mesomere
Division of lateral mesoderm
| Becomes kidney, excretory and reproductive tracts
175
Hypomere
Division of lateral mesoderm
- Coelom expands further
- Extends dorsomedially to enclose endoderm
- Has somatic layer (becomes parietal serosa) & visceral layer (becomes visceral serosa, musculature, heart/blood vessels, lymph vessels, gonads)
176
Dermatome
Division of epimere
- Expands deep to ectoderm
- Becomes dermis of integument, dermal muscles, dermal skeletal structrues
177
Myotome
Division of epimere
- Expands dorsally between ectoderm and sclerotome and ventrally between ectoderm and hypomere
- Becomes epaxial and hypaxial musculature, appendicular skeleton
178
Sclerotome
Division of epimere
- Surrounds notochord and neural tube
- Becomes vertebral column
179
Integumet
(Skin)
- Covering for the body of an organism
- One of the largest organs
- Used for protection and various other tasks such as respiration, temperature regulation, odour secretion, claws, hair, feathers, nails, horns, etc.
180
Primary body tissues
- Epithelial tissue
- Connective tissue
- Muscular tissue
- Nervous tissue
181
Epithelial Tissue
Layer(s) of cells that form a barrier
- Covers exposed surfaces as part of skin
- Lines body cavities - serosa, mucosa
- Cells are tightly bound together
- Apical exposed surface
- Basal surface that attaches to underlying body structures via connective tissue
- Usually avascular
- Few, if any, nervous structures
182
Dermis
One of two main layers of integument
- Deep
- Connective tissue
- Formed mainly from dermatome
- Usually relatively
- Vascularized
- Contains sensory receptors
183
Epidermis
One of two main layers of integument
- Superficial
- Epithelial tissue
- Formed from ectoderm
- Usually relatively thin
- Up to five layers: two main are stratum corneum & stratum basale
184
Trends in Integument
Tends to increase in thickness from basal tp derived taxa
| - Derived taxa can still have (semi)permeable
185
Waterproofing Skin
Change nature of epidermis
- Most superficial part becomes layer of dead, hardened cells
- Incorporation of insoluble proteins (keratins)
- Known as cornified or horny
186
Hypodermis
A.K.A. superficial fascia
- Deep to dermis
- Mainly loose connective tissue, adipose connective tissue (fat)
187
Stratum Corneum
Layer of epidermis
- Most superficial layer
- Thin
- Consists of dead cells
188
Stratum Basale
Layer of epidermis
- Most deep layer
- Relatively thick
- Living; contains dividing cells
- Most cells are keratinocytes, which are constantly being formed near the deep portion of s. basale
- Keratinocytes pushed superficially as new ones formed: take on keratins, flatten, die
189
Integument of Fishes
- Skin is relatively thin
- Epidermis made almost entirely of live cells
- Few, if any, keratinized cells
- Secretes mucus to help reduce drag, protect against bacteria (can contain various chemicals)
- May form specialized keratinized structures in some (i.e. denticles in lamprey)
- Scales found in more derived fishes formed partly from dermis and epidermis
190
Scales
Can include up to three components of hard tissue:
- Enamel (epidermal)
- Dentine (dermal)
- Bone (dermal)
191
Placoid Scales
Scales present in sharks
- No dermal bone
- Scale is formed by dentine that projects through epidermis and is capped by enamel
192
Dermal Bone
Formed from dermis
- Present in bony fish
- Forms plates that covered head and trunk of many ostracoderms and placoderms
- Broken into dermal scales more posteriorly
193
Bony Fish Scales
Formed by dermal bone
- May be capped by enamel/dentine
- Different kinds based on presence and relative proportions of enamel & dentine
194
Cosmoid Scale
Scale formed from bone capped by enamel and dentine
| - Seen in primitive sarcopterygians
195
Ganoid Scale
Scale formed by bone that is sometimes capped by enamel
| - Seen in primitive actinopterygians
196
Teleost Scale
Scale that is formed solely by bone
| - Seen in derived actinopterygians
197
Integument of Amphibians
Thin skin, mostly all live cells
- Thin stratum corneum provides some protection against mechanical abrasion and water loss
- Scales absent except in some caeciians
- Cutaneous respiration common and very important to some species
- Capillaries extend into lower epidermis
- Generally have mucus and poison glands
198
Integument of Reptiles
- Extensive keratinization
- Dermal bone may be present, but is not generally associated with scales: osteoderms, gastralia
- Few skin glands: mainly scent glands
199
Reptilian Scales
Usually lack underlying dermal bone contribution
Epidermal scales
- Fold in the surface of epidermis
- May be modified into crests, spines or horns
200
Osteoderms
Small pieces of dermal bone found under epidermal scales
| - Seen in some turtle shell bones, crocodilians, some reptiles, extinct reptiles
201
Gastralia
Collections of dermal bone within the abdominal region
202
Epidermal Derivatives
- Scales
- Calluses
- Nails/claws/hooves
- Hair
- Feathers
- Baleen
- Horns/antlers
- Glands
203
Nails, claws and hooves
Keratinized epidermal structures that tip the digits of amniotes
- Protect digits
- Used in climbing, defence, food gathering, etc.
204
Horns & antlers
Cranial appendages that are widespread, esp. among mammals
| - Used for defence, mate selection, dominance
205
True Horn
Keratinized sheath supported by unbranched bony core/spike
- Seen in cattle, antelope, goats, sheep
- Not shed
206
Antlers
Bone covered by velvety skin when immature
- Usually confined to males
- Shed annually
- Tend to be branched
207
Rhinoceros Horn
Keratinized epithelium made from fused, hairlike epidermal papillae
208
Giraffe Horn
Cartilage core that has been ossified and covered by skin
209
Hair
Mammalian feature
- Epidermal sheath that sits in a follicle extending into the dermis
- Dermal papilla supplies blood vessel
- Hair grows basally
- Cells are pushed up, become keratinized and die
210
Arrector pili
Small muscle associated with a single hair follicle, erects hair
211
Sebaceous glands
Glands associated with hair follicles
| - Secretes oily substance to lubricate and protect hair
212
Apocrine glands
Sweat glands used for chemical signalling and viscous secretion:
- Mammary glands
- Scent glands
213
Glands
Epidermal structures found in all vertabrate clades
| - Can be single celled or multicellular
214
Uropygial Gland
Found in birds
- Near base of tail
- Secretes oily substance used in preening to protect feathers and repel water
215
Salt Gland
Found in birds
- On head of some
- Secretes excess salt
216
Sudoriferous Glands
Sweat glands in mammals, two kinds:
- Eccrine
- Apocrine
217
Eccrine Glands
Sweat glands that secrete salt, urea, water
218
Mammary Glands
Modified apocrine glands that secrete milk
219
Scent Glands
Modified apocrine glands that secrete scents
| - Used to mark territory, in individual recognition, courtship
220
Skeleton
Composed of various kinds of connective tissue
221
Connective Tissue
- Formed by mesenchyme
- Reinforces epithelia and other soft body tissues
- Acts as a support for the body
- Consists of cells scattered through a matrix (that is normally secreted by the cells)
- Included cell types and materials determine structure, properties and function of the tissue
- Main types are bone and cartilage
222
Mesenchyme
Embryonic material mainly derived from epimere and hypomere
- Network of cells that links outer tube and developing organs
- Differentiates into connective tissue, most of the circulatory system, most muscles
223
Bone Tissue
- Heavily mineralized matrix
- Extremely metabolically active
- Osteocytes reside in lacunae within the matrix
- Highly vascularized
- Bone grows by expansion at surface
- Lacunae stellate connect with other chambers
224
Cartilage Tissue
- Different cartilage types based on differing materials
- Rigid, but not hard like bone
- Chondrocytes reside in spherical, isolated lacunae
- Avascular
- Not very metabolically active
- Grows by internal and surface expansion
225
Bone vs Cartilage
- Used to be thought that cartilage was primitive to bone, but not the case
- Each tissue has properties that make it suitable for different things
- Bone ideal for compression
- Fibrous cartilage ideal for tension
226
Parts of the Skeleton
- Dermal Skeleton
- Endoskeleton
- Heterotopic Skeletal Elements
227
Dermal Skeleton
Membranous bone that forms directly in connective tissue
- Generally relatively superficial
- Never performed by cartilage
- E.g. bony plates in early fish, osteoderms, turtles, armadillos, parts of the skull
228
Endoskeleton
Endochondral bone
- Lies deeper than dermal
- Always preformed by cartilage: replacement of embryonic cartilage by adult bony structure
- Forms most bones of the body
- Subdivided into somatic and visceral skeleton
229
Somatic Skeleton
Subdivision of endoskeleton
- Outer tube of body
- Formed by somites
- Two kinds: axial & appendicular
230
Axial skeleton
Kind of somatic skeleton
| - Forms most of skull, vertebral column, ribs
231
Appendicular skeleton
Kind of somatic skeleton
| - Forms paired appendages and limb girdles
232
Visceral Skeleton
Subdivision of endoskeleton
- Associated with branchial skeletons or derived from them
- Formed by neurectoderm
233
Heterotopic Skeletal Elements
Stray skeletal elements not associated with any other part of the skeleton
- Not preformed in cartilage
- E.g. sesamoid bones, small bone in diaphragm of camels, bone in septum of heart of ruminants, bone in upper eyelid of crocodile, baculum/os penis, os clitoris
234
Diaphysis
Shaft of a long bone
235
Epiphysis
Flared ends of a long bone
236
Epiphyseal Line
Line separating the epiphysis from the disphysis
237
Epiphyseal Plate
Layer of hyaline cartilage between the epiphysis and diaphysis of juveniles; ossified during development
238
Periosteum
Fibrous connective tissue surrounding a bone
239
Medullary Cavity
Hollow cavity within the diaphysis of a bone
240
Endosteum
Connective tissue lining the cavities and spaces within bones
241
Articular Cartilage
Cartilage found at the joints of bones
242
Postcranial Skeleton
Skeletal structures of the body not including the head
- Formed largely by endoskeletal elements
- Mostly somatic
- Mainly formed from mesenchyme
243
Vertebral Column
- Little muscular attachment in fishes; instead, most muscular force is exerted on myosepta
- Ribs develop at the intersections of connective tissue, increasing efficiency of muscular effort
- Precise rib formation depends on position
- Dorsal ribs at intersection of myoseptum and HSS
- Ventral ribs along coelomic cavity
244
Vertebral Types
- Amphiocoelous
- Procoelous
- Opisthocoelous
- Acoelous
- Heterocoelous
245
Amphicoelous Vertebrae
Vertebrae that are concave at both ends of the centrum
| - Typical of fishes and early tetrapods
246
Procoelous Vertebrae
Vertebrae whose centra are concave anteriorly and convex posteriorly
- Typical of amphibians and reptiles
247
Opisthocoelous Vertebrae
Vertebrae whose centra are concave posteriorly and convex anteriorly
- Typical of amphibians an reptiles
248
Acoelous Vertebrae
Vertebrae whose centra are nearly flat at both ends
| - Typical of the trunk of mammals and birds
249
Heterocoelous Vertebrae
Vertebrae whose centra are saddle-shaped
| - Typical of the neck vertebrae of birds
250
Trends in Vertebral Evolution
Tendency is for there to be increased differentiation along the column in increasingly advanced forms
- Fish: trunk & caudal
- Tetrapods: 1+ articulates with pelvic girdle (sacral)
- Advanced tetrapods: trunk vertebrae divided into cervical and dorsal
- Mammals: dorsal vertebrae divided into thoracic and lumbar
251
Embryology of Vertebrae
Develop from sclerotome of epimere
- Initially segmentally arranged
- Develop so they are intersegmentally arranged with respect to musculature
- This ensures that musculature forms across adjacent vertebrae
- Note: more variable in fish since myomeres exert force on myosepta not vertebrae
252
Evolution of Postcranial Skeleton
Fish
- Simple and small appendicular skeleton
- Dermal skeleton mostly behind operculum dominates
- Main element: cleithrum
- Can't bend neck
- Pectoral > pelvic
Tetrapods
- Large and more complex appendicular skeleton
- Needed to keep body off ground and for propulsion
- Cleithrum and clavicle reduced
- New interclavicle lies between clavicles
- Can move neck
- Pectoral < pelvic
253
Evolution of Pectoral Girdle
- Initially formed from dermal and endoskeletal parts, with fin supported by endoskeletal
- Endoskeletal portion expands, with scapular centre of ossification dominating
- Only clavicle remains of dermal elements in mammals
- Designed to absorb shock
254
Evolution of Pelvic Girdle
- Initially small and not attached to body
- Begins to extend dorsally and fuses with sacral vertebra(e)
- Now, hind limbs provide nearly all force in tetrapod locomotion
255
Evolution of Posture
- In early tetrapods, limbs were perpendicular to body axis and extended laterally (sprawled posture); move mainly by fish-like lateral movements
- Manus and pes rotated to point forward; lateral bending of body propelled each forward
- Limbs became tucked underneath body and more vertically aligned with parasagittal plane; efficient for-aft motion
