BISC 1112 Lecture Notes - Lecture 14: Dorsal Nerve Cord, Nictitating Membrane, Umbilical Cord
28 Aug 2016
School
Department
Course
Professor
Fetal Pig
Lab Intro
-Phylum Chordata
•most familiar animals from fish to animals are classified in this phylum
•members share several important characteristics:
-presence of pharyngeal gill slits at some point
-primary skeletal axis called the notochord that consists of an axial rod of cells
•remains throughout the life of the lower chordates, but in the higher vertebrates it is
replaced by the vertebral column in the adult
-blocks of muscles (myotomes) surrounding the notochord
-a hollow, dorsal nerve cord
-a post-anal tail
Phylum Chordata
-can be divided into several major clades:
•Cephalochordate
-28 living species includes lancelets, small, motile fish-like animals found in the shallow waters
of warm seas
•Urochordata (or Tunicata)
-clade of 2,000 living species includes salps, larvacea, and the sea squirts
•have u-shaped body, enclosed in a transparent covering
•marine-living sea squirts may be motile or sessile, colonial or solitary
•Vertebrata
-clade is distinguished by the presence of both an enlarged brain enclosed in a protective
cranium and a segmented vertebral column
-bodies of vertebrates are usually divided into a head, neck, trunk, and tail region and the
sexes are generally separate
-most are motile and inhabit nearly all ecological niches existing on earth
-composed of the following clades:
•Petromyzontida, Chondrichthyes, Actinopterygii, Actinistia, Dipnoi, Amphibia, Reptilia, and
Mammalia
External Structures
-females
•genital papilla
-fleshy tubercle projected from the urogenital orifice
•location of urogenital orifice is immediately ventral to the anal opening
-males
•scrotal sacs
-swellings located beneath the anal opening
•location of the urogenital orifice is posterior to the umbilical cord
-nipples
•presence on the ventral surface of both sexes
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-epitrichium or periderm
•thin, transparent layer usually displaced before birth by the hairs growing beneath it
•may cover skin
-eyes
•pupils
•iris
•sclera
-white layer around the iris that serves as an elastic layer of connective tissue
•cornea
-transparent area of the sclera that covers the lens and iris
•nictitating membrane
-located at the inner corner of the eye
-ears
•pinna
-pointed area of the external ear that is designed to catch sound
•external auditory meatus
-ear canal
•tympanic membrane
-eardrum
Respiratory System
-External Respiratory Structures:
•tongue
•teeth
•hard palate
•smooth soft palate on the roof of the mouth
•pharynx
-back of the mouth
-plays a role in both respiration and digestion
-three pharyngeal openings
•glottis
-opening to the larynx
•esophagus
-opening to the digestive system
•nasal passage
-opening at the top back part of the soft palate
•internal nares
-can see this by opening the soft palate
-connects to the external nares
•epiglottis
-flap of tissue hanging down at the back of the throat
-seals off the opening to the respiratory passage when food and liquids are swallowed
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Phylum chordata: most familiar animals from fish to animals are classified in this phylum, members share several important characteristics: Presence of pharyngeal gill slits at some point. Primary skeletal axis called the notochord that consists of an axial rod of cells: remains throughout the life of the lower chordates, but in the higher vertebrates it is replaced by the vertebral column in the adult. Blocks of muscles (myotomes) surrounding the notochord. Can be divided into several major clades: cephalochordate. 28 living species includes lancelets, small, motile fish-like animals found in the shallow waters of warm seas: urochordata (or tunicata) Clade of 2,000 living species includes salps, larvacea, and the sea squirts: have u-shaped body, enclosed in a transparent covering, marine-living sea squirts may be motile or sessile, colonial or solitary, vertebrata. Clade is distinguished by the presence of both an enlarged brain enclosed in a protective cranium and a segmented vertebral column.
