Comparative Anatomy Sensory and Endocrine Organs

1
Comparative AnatomySensory and Endocrine Organs

• Note Set 14
• Chapter 15 17

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Sense Organs

• Monitor external internal environment
• Somatic or visceral receptors
• Specific or general

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Special Somatic ReceptorsNeuromasts

• In skin of fish and amphibians
• Monitors mech, elect, and chem stimuli
• Ampullae of Lorenzini in shark snout

Figure 16.1 Ampullae of Lorenzini in shark.
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Special Somatic Receptors (cont.)Neuromasts

• Pit organs along shark gill region
• Lateral line canal
• Linear series
• Derived from ectodermal placodes

Figure 16.2 External openings of neuromast
organs in Squalus.
Figure 16.3 Neuromast organ and lateral line
canal in a fish.
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Special Somatic ReceptorsMembranous Labyrinth

• Vertebrates have pair of fluid filled membranous
  labyrinths
• Filled with endolymph
• Surrounded by perilymph

Figure 16.5 Membranous labyrinths of human.
Figure 16.4 Left membranous labyrinth of
craniates semicircular canals (1, 2, 3),
sacculus (s) and utriculus (u).
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Special Somatic Receptors (cont.)Membranous
Labyrinth

• Semicircular canals, utriculus, and sacculus
• Inside canals
• Otoliths
• Sensory hairs- perceive motion
• Angular motion detected by semicircular canals
• Linear motion detected by utriculus and sacculus

Figure 16.6 Vestibular apparatus.
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Figure 16.7 Human anatomy of the ear.
Figure 16.8 Anlagen of amniote inner ear
(otocyst). Embryonic head (a) and cross section
of head (b).
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Special Somatic Receptors (cont.)Membranous
Labyrinth

• Lagena
• Out pocketing of sacculus wall
• Gives rise to cochlea in mammals
• Organ of Corti

Figure 16.9 Cochlea and organ of corti in
mammal.
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Special Somatic Receptors (cont.)Membranous
Labyrinth

• Weberian ossicles
• Fish transmit sound waves
• Modified transverse process
• Sinus impar (some fish)
• Assists in transport of sound

(a)
(b)
Figure 16.10 (a) weberian ossicles (b) weberian
apparatus for transmitting swim bladder
vibrations to ear.
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Special Somatic Receptors (cont.)Membranous
Labyrinth

• Middle Ear of Tetrapods
• Canal from evagination of 1st pharyngeal pouch
• Eustachian tube
• Communication btwn pharynx and middle ear

Figure 16.11 Position of eustachian tube.
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Special Somatic Receptors (cont.)Membranous
Labyrinth

• Middle Ear of Tetrapods
• Bones
• Malleus, incus, and stapes
• Derived from 1st and 2nd visceral arches
• Stapes is columella in reptiles and birds

Figure 16.12 Middle ear bones.
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Special Somatic Receptors (cont.)Membranous
Labyrinth

• Middle Ear of Tetrapods

Figure 16.13 Development of the middle ear bones.
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Special Somatic Receptors (cont.)Membranous
Labyrinth

• Outer Ear of Tetrapods
• Pinnae
• Ear drum set back into skull
• Crocs, birds, and mammals
• Tympanic membrane on outside
• Frogs
• External auditory meatus
• Canal leading to tympanic membrane

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Special Somatic ReceptorsInfrared Receptors

• Pits that open to surface
• Btwn epidermal scales
• Loreal pits
• Pit vipers
• Btwn nostril and eye
• thermosensitive
• Labial pits
• Pythons
• Other thermosensitive pits
• Appear similar to neuromasts

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Special Somatic ReceptorsLight Receptors

• Photoreceptors
• Lateral eyes
• Median eye (3rd or pineal eye)
• On top of head
• Has lens and cornea
• Do not form retinal images
• Ex lamprey, ganoid fish, larval anurans, lizards

Figure 16.14 Parietal eye.
Figure 16.15 Parapineal organ of iguana.
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Special Somatic Receptors (cont.) Light
Receptors

• Median eye (3rd or pineal eye) (cont.)
• Part of epiphyseal complex
• Anterior parapineal is often photosensitive
• Lamprey- both pineal and parapineal are
  photosensitive
• Lizard- parapineal becomes 3rd eye
• Frontal organs
• 3rd eye in larval frogs
• Photosensitive

Figure 16.16 Epiphyseal complex of lamprey and
embryonic and adult lizard.
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Special ChemoreceptorsOlfactory Organs

• Ectodermal placodes
• Sink into head
• Internal naris- opening inside
• Lungfish and tetrapods
• External naris- opening outside
• Fish
• Higher vertebrates possess both types

Figure 16.17 Internal and external naris shown
and vomeronasal organ.
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Special Chemoreceptors (cont)Olfactory Organs

• Vomeronasal organ (Jacobsons Organ)
• Olfactory mechanisms isolated form nasal
• Snakes and lizards
• Insert forked tongue into organ

(a)
(b)
Figure 16.18 Snake collecting scent molecules
(a) that are then delivered to the vomeronasal
organ by the tongue (b).
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Special ChemoreceptorsOrgans of Taste

• Taste buds
• Similar to neuromasts
• In oral cavity and pharynx

Figure 16.19 Anatomy of the taste bud.
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Endocrine Organs

• Ductless organs
• Secrete hormones
• Derived from the 3 germ layers

Figure 16.20 Embryonic germ layers.
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Pituitary Gland
Figure 16.21 Phylogeny of the vertebrate
pituitary.
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Pituitary Gland (Hypophysis)

• Derived from ectoderm
• Two divisions
• Neurohypophysis (post. pit.)
• Adenohypophysis (ant. pit.)

Figure 16.22 Anterior and posterior pituitary.
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Pituitary Gland (cont.)

• Neurohypophysis
• Infundibulum of diencephalon
• Stores hormones
• Adenohypophysis
• Cells evaginate away from stomadeum
• Secretes hormones
• Rathkes pouch

Figure 16.23 Embryogenesis of the amniote
pituitary.
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Caudal Neurohemal Organ

• Endocrine gland unique to some fish
• Urophysis
• Neurosensory organ
• Occurs at tip of tail off of spinal cord

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Pineal

• Derived from ectoderm
• Produces melatonin
• Gonadal regulator
• Photoperiodism

Figure 16.24 Location of the pineal gland in the
human brain.
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Adrenal Gland

• Adrenal Medulla
• Derived form ectoderm
• From neurocrest cells
• Adrenal Cortex
• Derived from mesoderm

Figure 16.25 Cross section of Rt adrenal gland
(top) and anatomical position of the adrenal
glands.
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Gonads

• Derived from mesoderm
• Within kidney tissue in some rayfin fish
• Corpuscles of Stannius

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Endodermal Origin

• Pancreatic Islets of Langerhans
• Thyroid gland
• Foramen Cecum- reminant of thyroid evagination
• Bursa of Fabricius
• Outpocket of cloaca
• Thymus in nature

Figure 16.27 Mammalian thyroid development.
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Pharyngeal Pouches

• Derived from endoderm
• Fish
• Pouches 2, 3, 4, 5 (dorsal)- thymus
• Pouch 5 (ventral)- ultimobranchial bodies
• Amphibians
• Pouches 3, 4, 5 (dorsal)- thymus
• Pouch 5 (ventral)- ultimobranchial bodies

Figure 16.28 Contributions of the embryonic
pharyngeal pouches to development of endocrine
glands.
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Pharyngeal Pouches (cont.)

• Mammals
• Pouches 3 4 (dorsal)- thymus
• Pouches 3 4 (ventral)- parathyroids
• No ultimobranchial bodies

Figure 16.29 Contributions of the embryonic
pharyngeal pouches to development of endocrine
glands.
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Literature Cited

• Figure 16.1- http//people.eku.edu/ritchisong/342n
  otes11.html
• Figure 16.2, 16.4, 16.8, 16.10 (b), 16.15, 16.16
  16.17- Kent, George C. and Robert K. Carr.
  Comparative Anatomy of the Vertebrates. 9th ed.
  McGraw-Hill, 2001.
• Figure 16.3- http//fig.cox.miami.edu/cmallery/15
  0/neuro/senses.htmillusions
• Figure 16.5- http//anatomy.iupui.edu/courses/hist
  o_D502/D502f04/lecture.f04/Earf04/Ear.f04.html
• Figure 16.6- http//faculty.etsu.edu/currie/study/
  hearing.htm
• Figure 16.7- http//anatomy.iupui.edu/courses/hist
  o_D502/D502f04/lecture.f04/Earf04/Ear.f04.html
• Figure 16.9- http//faculty.etsu.edu/currie/study/
  hearing.htm
• Figure 16.10 (a) http//www.voiceproblem.org/anato
  my/learning.asp Figure 16.11- http//www.familydoc
  tor.co.uk/htdocs/deafness/deafness_specimen.html
• Figure 16.12- http//137.222.110.150/calnet/Aud/pa
  ge2.htm
• Figure 16.13- http//anatomy.iupui.edu/courses/his
  to_D502/D502f04/lecture.f04/Earf04/Ear.f04.html
• Figure 16.14- http//www.anapsid.org/parietal.html
  

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Literature Cited

• Figure 16.18- http//www.massasauga.ca/stewardship
  _guide/section_2/pg16.htm
• Figure 16.19- http//www.csus.edu/indiv/l/loom/oct
  1920f05.htm
• Figure 16.20- http//www.bme.gatech.edu/vcl/Tissue
  _Engineering/Background/2_cell_types.htm
• Figure 16.21, 16.23, 16.27, 16.28 16.29-
  Kardong, K. Vertebrates Comparative Anatomy,
  Function, Evolution. McGraw Hill, 2002.
• Figure 16.22- http//www.abcbodybuilding.com/magaz
  ine03/endocrineinsanity1.htm
• Figure 16.24- http//webs.uvigo.es/endocrinologia/
  marco_izquierda.html
• Figure 16.25- http//www.bartleby.com/61/imagepage
  s/A4adregl.html