PRACTICAL SUMMARY
PRACTICAL PM1 LECTURE
Primary function of the pharynx in Chordates
Filtering feeding (no respiratory structures)
• Gill bars and gill slits
• Cilia conduct the flow of water
• Endostyl for mucus production (exocrine) (1)
• Epipharyngeal groove (2)
Secondary function of the pharynx
Transportation of water and food: GI-tract & respiration
• Gill septa with internal gill rakers (protection and sometimes filter feeding)
• Respiratory epithelium (gill filaments and lamellae)
• Muscles regulate flow of water
• Thyroid (endocrine) is homologous with endostyl (exocrine)
Tertiary function of the pharynx
Mammals (Amniotes)
Part of the digestive & respiratory system, involved in sound transmission.
• Different pharynx regions and the first tracheal rings
• Auditory ossicles
• Muscles attached to the various elements
Neurons in vertebrates
,Positions of spinal nerves (Kardong 16.19)
Spinal nerves in the sea lamprey (Kardong 16.19)
Chordate characteristics in this picture:
Notochord
Dorsal nerve cord
Post-anal tail
(The picture doesn’t show other chordate
characteristics like pharyngeal slits & endostyle /
thyroid)
Vertebrate characteristics in this picture:
Arcualia / vertebrae
Epidermis, dermis
(The picture doesn’t show the braincase,
tripartite
brain, muscular pharynx, endocrin system, duplication of the HOX-genes and ventral heart).
MORPHOLOGY OF THE LAMPREY: PM2
The brain of the lamprey is smaller than most other vertebrates. The fore brain region (telecephalon), associated with smell, and
the mid-brain region(mesencephalon, associated with vision, are well developed. However, the cerebellum and the hind brain,
associated with taste and acousticolateral systems, are both small. The medulla oblongata is one of the largest brain regions as it
is associated with the trigeminal nerve, which controls the extensive musculature associated with sucking. The eye has a dermal
and a scleral cornea. A lamprey accommodates to a more distant object by contracting a corneal muscle, that pulls the corne
inward and pushes the lens back.
,Venous system larval lamprey dorsal
view
Ammocoetes; oblique horizontal section, detail head
Ammocoetes; oblique horizontal section
, Even though the respiratory water flows in and out through the same gill slit in adult lamprey, there might still be unidirectional
flow over the gills and a counter current principle in place with respect to blood flow. The contraction of the gill basket is
achieved through muscle activity: the relazation by the elasticity of the cartilaginous elements.
The ammocoetes is a filter feeder . the fine organic mater extracted from the stream of water is pumped through the pharynx by
the muscular velum. Fine food particles are selectively captured in the mucus lining the parabranchial pouches nect to the
pharyngeal arches using a mucus gland. The endostyle similar to that in amphioxus.
What is the relation between hypophyseal pouch and the adenohypophysis?
How does the configuration of nerve fiber bundles in the spinal cord differ by higher vertebrates.
PRACTICAL PM1 LECTURE
Primary function of the pharynx in Chordates
Filtering feeding (no respiratory structures)
• Gill bars and gill slits
• Cilia conduct the flow of water
• Endostyl for mucus production (exocrine) (1)
• Epipharyngeal groove (2)
Secondary function of the pharynx
Transportation of water and food: GI-tract & respiration
• Gill septa with internal gill rakers (protection and sometimes filter feeding)
• Respiratory epithelium (gill filaments and lamellae)
• Muscles regulate flow of water
• Thyroid (endocrine) is homologous with endostyl (exocrine)
Tertiary function of the pharynx
Mammals (Amniotes)
Part of the digestive & respiratory system, involved in sound transmission.
• Different pharynx regions and the first tracheal rings
• Auditory ossicles
• Muscles attached to the various elements
Neurons in vertebrates
,Positions of spinal nerves (Kardong 16.19)
Spinal nerves in the sea lamprey (Kardong 16.19)
Chordate characteristics in this picture:
Notochord
Dorsal nerve cord
Post-anal tail
(The picture doesn’t show other chordate
characteristics like pharyngeal slits & endostyle /
thyroid)
Vertebrate characteristics in this picture:
Arcualia / vertebrae
Epidermis, dermis
(The picture doesn’t show the braincase,
tripartite
brain, muscular pharynx, endocrin system, duplication of the HOX-genes and ventral heart).
MORPHOLOGY OF THE LAMPREY: PM2
The brain of the lamprey is smaller than most other vertebrates. The fore brain region (telecephalon), associated with smell, and
the mid-brain region(mesencephalon, associated with vision, are well developed. However, the cerebellum and the hind brain,
associated with taste and acousticolateral systems, are both small. The medulla oblongata is one of the largest brain regions as it
is associated with the trigeminal nerve, which controls the extensive musculature associated with sucking. The eye has a dermal
and a scleral cornea. A lamprey accommodates to a more distant object by contracting a corneal muscle, that pulls the corne
inward and pushes the lens back.
,Venous system larval lamprey dorsal
view
Ammocoetes; oblique horizontal section, detail head
Ammocoetes; oblique horizontal section
, Even though the respiratory water flows in and out through the same gill slit in adult lamprey, there might still be unidirectional
flow over the gills and a counter current principle in place with respect to blood flow. The contraction of the gill basket is
achieved through muscle activity: the relazation by the elasticity of the cartilaginous elements.
The ammocoetes is a filter feeder . the fine organic mater extracted from the stream of water is pumped through the pharynx by
the muscular velum. Fine food particles are selectively captured in the mucus lining the parabranchial pouches nect to the
pharyngeal arches using a mucus gland. The endostyle similar to that in amphioxus.
What is the relation between hypophyseal pouch and the adenohypophysis?
How does the configuration of nerve fiber bundles in the spinal cord differ by higher vertebrates.
