ANIMAL GROWTH AND DEVELOPMENT: The Tadpole (External Gill Stage)
STRUCTURE FUNCTIONS ORIGIN FATE
ECTODERMAL DERIVATIVES CENTRAL NERVOUS SYSTEM BRAIN
prosencephalon Central nervous system Neural tube [from neural ectoderm]
telencephalon, diencephalon (forebrain); also give rise to parts of
brain and eye rudiments telencephalon (future
site)
language & communication, movement,
olfactory, memory emotion Neural tube [from neural ectoderm]
CEREBRAL HEMISPHERE [telencephalon (cerebral cortex,
basal ganglia, corpus stratum, olfactory bulb)]
diencephalon (future
site) receive input from optic nerves Neural tube [from neural ectoderm]
thalamus/hypothalamus, diencephalon
mesencephalon ? Neural tube [from neural ectoderm] optic lobes, corpora bigemina; cerebral aqueduct rhombencephalon autonomic functions Neural tube [from neural ectoderm] ?
OTHER
STRUCTURES
prosocoel divides with the prosencephalon into the telocoel and diocoel
Neural tube neurocoel (from neural ectoderm)
first and second ventricles of cerebral hemisphere
telocoel Relays nerve axons from the frontal lobe and
occipital lobe neurocoel
first and second ventricles of cerebral hemisphere
diocoel
Communicates with the lateral ventricles anteriorly, and with the mesencephalic duct
posteriorly
Neural tube neurocoel (from neural ectoderm)
third ventricle of cerebral hemisphere [3rd brain ventricle]
epiphysis
Releases hormones that play a major role in seasonal breeding, metabolism, hibernation in
animals, and in sexual development
neural tube (from neural ectoderm) pineal body or gland
infundibulum
Carries axons from the magnocellular neurosecretory of the hypothalamus down to the posterior pituitary where they release their
hormones into the blood
neural tube (from neural ectoderm) posterior pituitary gland
hypophysis Secretes hormones for growth, sex organ functions, and blood pressure
Anterior lobe of hypophysis: stomedeal epithelium (from epidermal ectoderm); posterior lobe
from the neural tube (from neural ectoderm)
anterior pituitary gland
mesocoel Relays between ventricles; connects the 3rd
and 4th brain ventricles neurocoel
optic ventricles, tectum (from the roof); cerebral aqueduct rhombocoel
Connects central canal of spinal chord to cerebral aqueduct. Relays nerve axons from
the pons, and the medulla oblongata
neurocoel fourth brain ventricle, aqueduct of Sylvius
plexus
basal plates Project motor fibers to skeletal muscle and
form the ventral roots of the spinal nerves neural tube (from neural ectoderm)
Gives rise to motor neurons; myelencephalon posterior choroid
plexus Produce cerebrospinal fluid neural tube (from neural ectoderm) posterior choroids plexus
SPINAL CORD
spinal cord Carries sensory signals and motor innervation to most of the skeletal muscles in the body
caudal portion of neural tube (from
neural ectoderm) spinal cord central canal Carries cerebrospinal fluid neurocoel; Neural tube (from neural
ectoderm) central canal
PERIPHERAL
NERVOUS SYSTEM
ORGANS OF THE
SENSES
EYE
optic cup Contains lens and other parts of the eye, used
for sight neural tube (from neural ectoderm) iris, optic cup pigmented epithelium Help to optimize visual contrast by reducing neural tube (from neural ectoderm) pigmented epithelium
retina
Innermost coat of the eye, is a delicate membrane whose sensory epithelium provides
a sensitive surface. It contains a pigmented layer lining the choroids and inner retina propoe consisting of neurosensory cells called
rods and cones.
neural tube (from neural ectoderm) retina
optic lens Focus the light rays onto the retina by refraction.
EPIDERMAL ECTODERM epidermal placodes (ectoderm,
neural tube)
optic lens
EAR
otic vesicles for hearing and equilibrium; auditory vesicle epidermal placodes (ectoderm) INNER EAR sacculus, utriculus OLFACTORY
ORGANS
olfactory epithelium Lines olfactory canal EPIDERMAL ECTODERM
epidermal placodes (ectoderm) olfactory epithelium
olfactory canal For smelling EPIDERMAL ECTODERM
epidermal placodes (ectoderm) Choanal canal external nares Opens to the exterior (sor to the air to come in) EPIDERMAL ECTODERM
epidermal placodes (ectoderm) external nares internal nares It is an extension of the tubular opening from
the external nares to the pharynx
EPIDERMAL ECTODERM
epidermal placodes (ectoderm) internal nares
CRANIAL NERVES
optic nerves (II)
A large nerve; curves around to the ventral side and emerges from an X-shaped structure called optic chiasma; It supplies retina of the
eye
NEURAL TUBE (neural ectoderm,
trigeminal ganglion (V)
Sends branches to the mandibular and
maxillary processes of the first visceral arches neural crest trigeminal(V) nerve
acoustico-facialis ganglion (VII-VIII)
innervates facial muscles, utriculus and sacculus of inner ear. FACIAL- -it is related to
facial muscles and taste buds;AUDITORY -sense nerve, which is associated with geniculate ganglion; innervates facial muscles,
utriculus and sacculus of inner ear
neural crest
facial (VII) nerve, auditory(VIII) nerve Nerve VII innervates the facial muscles; nerve VIII innervated the utriculus and sacculus of the inner
ear glossopharyngeal
ganglion (IX) Sends branches to the first branchial arch neural crest glossopharyngeal(IX) nerve
SKIN
epidermis outer protective covering (stratified epithelium) epidermal placodes (ectoderm) skin, epidermis melanophores Contains melanin- -Gives color to the skin neural crest melanophores/ melanocytes
Additional
structures
oral suckers adhesive glands *(organ of adhesion) epidermal placodes (ectoderm) disappears
oral cavity
Wide chamber that is exposed upon opening the mouth; for ingesting prey and for adult frogs
- - passageway of air into the lungs; receives food
Rupturing of oral plate epidermal
ectoderm buccal cavity, mouth stomodeum
depression Lines the mouth cavity epidermal placodes (ectoderm) Lining of mouth cavity ENDODERMAL
DERIVATIVES
FOREGUT
RESPIRATORY
SYSTEM
pharynx Source of several endocrine glands such as thyroid and parathyroid
anterior portion of endodermal gut
(endoderm) PRIMITIVE GUT pharynx
pharyngeal pouch secretes hormone directly to the bloodstream PRIMITIVE GUT middle ear, Eustachian tube, Parathyroids
external gills *Carries respiration, which require no gill cleft, while the larva is still confined to the egg-mass.
Primitive gut (endodermal
evagination) disappears
LUNGS endoderm lungs
lung buds The single short tubular connection opens into
the foregut Primitive gut lungs
trachea Also known as windpipe, where air passes to
two bronchi, one leading to each lung primitive gut/ endodermal gut trachea
THYROID GLAND
(It drains the tail); Endocrine gland that secretes hormones which stimulates metabolism and influence development and maturation in vertebrates and a hormone which
lowers blood calcium levels blood calcium levels in mammals
DIGESTIVE SYSTEM esophagus transfers food (bolus) to the stomach; by
peristalsis endodermal gut/primitive gut esophagus stomach
Temporary storage and initial digestion of food; secretes digestive enzymes for the digestion of
food
endodermal gut/primitive gut stomach
liver
Produces bile which aids in digestion and absorption of fats, prepares nitrogenous wastes
for disposal and detoxifies poisonous chemicals in the blood
endodermal gut/primitive gut liver gall bladder stores and releases bile endodermal gut/primitive gut gall bladder
MIDGUT
midgut (consist of a large yolk cells) Where most of the intestines are derived from
PRIMITIVE GUT;archenteron
(endoderm) duodenum, ileum, small intestine
yolk Nutrients stored in the egg endoderm disappears
HINDGUT large intestine and rectum of the
adult frog hindgut Posterior part of alimentary canal PRIMITIVE GUT ; archenteron
posterior to yolk mass (endoderm) large intestine cloaca
Common opening for digestive, urinary and reproductive tracts in all vertebrates except
most mammals
primitive gut cloaca
anus The opening where feces are expelled from inside the body
in the region of blastopore/blastoporal lip
(proctodeum)
anus
NOTOCHORD axial support chordamesoderm disappears
MESODERMAL DERIVATIVES EPIMERE SKELETON AND MUSCLES dermatome
Group of tissues which develop into the skin; dermal layer of skin, intermuscular connective
tissues of both somatic and appendicular muscles, connective tissue layers of the skin.
epimere (mesenchyme) appendicular musculature, dermis
myotome Group of tissues that develop into the body wall
muscle epimere (mesenchyme)
axial musculature; gives rise to most skeletal muscles of trunk, striated
muscles, appendicular skeleton, muscles of the appendages sclerotome Group of tissues that develop into the vertebrae epimere (mesenchyme) vertebral column; sclerotomal sheath,
axial skeleton branchiomeric
muscles
For closing the mouth, aids in swallowing,
movement of the shoulder epimere (mesenchyme)
become the muscles operating the mouth
parachordal cartilage Fuse to form the basal plate which is pierced with openings for the exit of cranial nerves
NEURAL CREST [epimere (mesenchyme)]
floor of chondrocranium, floor of ethnoid plate / intranasal plate prechordal/trabecular
cartilage
Forms ethmoid plate which separates the nasal cavity from the brain
NEURAL CREST [epimere
(mesenchyme)] floor of ethnoid plate/intranasal plate
visceral arches
[For breathing, support of tongue and larynx] *Visceral skeleton that supports pharynx. Transmit the aortic arches from the ventral aorta to the dorsal aortic roots. Support the gills
and the blood vessels associated with the gills.
epimere (mesenchyme), ectoderm, mesoderm, endoderm
visceral skeleton that supports pharynx, forms the jaw hypobranchial
cartilage Moves and stabilizes larynx and hyoid neural crest part of visceral skeleton
MESOMERE
EXCRETORY
SYSTEM
pronephros kidney Filters urine from the pericardium mesomere (intermediate mesoderm)
most disappear replaced by mesonephric kidney (duct), small
portion becomes mesonephron (functional mesonephros) pronephric duct Where wates and water are swept into to be
secreted through the cloaca mesomere (intermediate mesoderm)
stimulates the development of mesonephric tubules, disappears and
replaced by mesonephric duct
COELOM hypomere body cavities
pericardial cavity Encloses the heart
cavity formed when hypomere separates into splabchnic and somatic (coelom, splanchnic
mesomere)
body cavity, pericardial cavity
parietal pericardium Lines the wall of pericardial cavity somatic hypomere/ somatic
mesomere parietal pericardium visceral pericardium Surface epithelium of the heart splanchnic hypomere/ splanchnic
mesomere visceral pericardium peritoneal cavity Surrounds the gut coelom/ splanchnic mesomere pleuroperitoneal cavity parietal peritoneum Surface epithelium of the gut SOMATIC MESODERM parietal peritoneum
visceral peritoneum Lines the wall of visceral organs splanchnic mesoderm visceral pericardium also, smooth muscle of the gut
AORTIC ARCH splanchnic mesoderm
I & II never develop; III external and internal carotids; IV systematic arch;
V- disapears; VI - pulmocutaneousartery efferent branchial
vessels
It supplies blood to the brain; the deep head
sutures and arm splanchnic mesoderm
afferent branchial vessels
It supplies blood to the tongue, the arm, and
the floor of the mouth splanchnic mesoderm
dorsal aorta (paired,
HEART truncus arteriosus Receives low oxygen blood from right ventricle
and oxygen rich blood from left ventricle splanchnic mesoderm truncus arteriosus conus arteriosus Serves as the base for all arteries splanchnic mesoderm conus arteriosus
atrium Receives blood returning to the vertebrate
heart splanchnic mesoderm right and left auricles
ventricle Pumps blood out of the heart splanchnic mesoderm ventricle common cardinal vein Serves as a major return channel to the heart;
receives anterior and posterior cardinal vein splanchnic mesoderm anterior vena cava
sinus venosus Pacemaker of the heart splanchnic mesoderm sinus venosus
OTHER PARTS
anterior cardinal vein Major drainage channel from the cephalic part
of the body splanchnic mesoderm jugular/subclavian vein posterior cardinal
vein
Major drainage channel from the caudal part of
the body splanchnic mesoderm
posterior vena cava, some will degenerate
caudal artery Supplies blood to the tail splanchnic mesoderm disappears
caudal vein It drains the tail splanchnic mesoderm disappears
gill capillaries In here, gas exchange occurs between the
blood and the water bathing the gills. splanchnic mesoderm disappears vitelline veins Collects blood from the liver and brings it to the
sinus venosus splanchnic mesoderm
posterior vena cava anterior section of postcaval vein, hepatic system, (hepatic vein, hepatic portal vein),
