Anatomy 241 Exam I chapter 2
Terms
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copy deck
- organisms with bilaterial symmetry
- bilateria
- organisms with a fluid filled body cavity
- coelomates
- "first mouth" Animals which develop a mouth from the blastopore
- protostomes
- "second mouth" Animals which develop a mouth from the opposite end of the digestive tract.
- deuterostomes
- What are the four fundamental features that chordates share?
-
dorsal hollow nerve cord
notochord
postanal tail
pharyngeal slits - The notochord serves as an "_" and flexes laterally from side to side.
- elastic rod
- the notochord with a fluid core may be classified as a _
- hydrostatic organ
- the pharynx, part of the digestive tract, is located just _ to the mouth
- posterior
- pharyngeal slits likely first evolved to aid in _ and later with _
- feeding, respiration
- cilia that line the pharynx establish the _ of water and move _ into the digestive tract
- current, food laden mucus
- _ are an assortment of invertebrates whose structure and design may represent chordates at their origins
- protochordates
- the three protochordates:
-
Hemichordata
Urochordata
Cephalochordata -
Defination of
1. Hemichordata
2. Urochordata
3. Cephalochordata -
1.half chordates
2.tail backstring
3.head chordate -
Hemichordates are marine worms that appear to link _ and _
they lack a _ and _ - Echinoderms, Chordates, notochord, tail
- hemichordates have a structural _ which was thought related to the notochord, but has failed genetic comparisions.
- stomochord
- Hemichordates exist within 1 of 2 taxonomic groups
-
Enteropneusta
Pterobranchs -
Definations:
1. enteropneusta
2. pterobranchs -
1. burrowing animals
2. sessile animals -
enteropneusta "_ worms" are marine burrowing worms
Their body is divided into three regions: -
acorn
1. proboscis
2. collar
3. trunk - each region of enteropneusta has its own coelom (3)
- protocoel, mesocoel, metacoel
- The first "true" members of the phylum chordata and at some point of their life cycle they generally show all four of the characteristics common to chordates.
- Urochordata
-
Urochordates may be divided into 3 taxonomic groups:
_ - sessile
_ and _ - pelagic (plankton) -
Ascidiacea
Larvacea & Thaliacea - Ascidians "_" do not greately resemble what we think of as chordates, but the _ state exhibits all 4 chordate characteristics.
- sea squirts, larval
- Ascidians often refered to as "_" because the adult forms are covered by a covering called a tunic
- tunicates
- Amphioxus is a _ that we studied in lab
- cephalochordata
- cephalochordata, anatomically simple animals that are designed to be suspension feeders based on their _ (much like _)
- pharyngeal filtering aparatus, protochordates
- The oldest known member of the cephalochordate is the _ which is an extant version of the _ (Amphioxus)
- Pikala, Branchiostoma
- Amphioxus has muscles arranged in segments (_) which are seperated from one another by partitions (_)
- myomeres, myosepta
- The _ and _ contraction of these muscles propels amphioxus through the water and aides in burrowing into the sediment.
- orderly, sequential
- In the digestive system of the Amphioxus food first moves into the _ before entering the pharynx.
- oral hood
- _ project outward from the oral hood and prevent large particles from entering
- Buccal cirri
- _ tracts inside the oral hood give the impression of rotation and are collectively termed the "_"
- ciliated, wheel organ
- _ - one of the dorsal tracts in the vestibule (similar to the wheel organ)
- Hatschek's pit
- some propose that the Hatschek's Pit may be the forerunner to the vertebrate _ gland.
- pituitary
- The trapping of food (Amphioxus) occurs in a _ - _ direction.
- ventral - dorsal
- the _ secretes mucus to trap food
- endostyle
- _ move the mucus dorsally
- cillia
- the food trapped in the mucus is directed to the _ and then into the digestive tract.
- epipharyngeal
- The posterior wall of the oral hood is defined by a diaphragm called the _
- velum
- sensory structures (_) sense and sort material before it passes through the opening of the velum and into the pharynx
- velar tentacles
- water that enters the pharynx passes through the pharyngeal slits and exits the body via the _ in the posterior portion of the _
- atriopore, atrium
- the midgut diverticulum (cecum) is thought to be the forerunner of the liver due to: (2)
-
anatomical location
blood supply - the hepatic diverticulum may also be related to the _ because cells in the wall secrete digestive enzymes.
- pancreas
- The digestive (GI tract) of the anphioxus includes: (3)
-
midgut
ileocolic ring
hindgut - Waste materials exit the body via the
- anus
- The amphioxus has _ heart
- no
- the task of pumping blood for the amphioxus is distributed among several _
- blood vessels
-
Blood circulation is laid out on the same general pattern as that of the _:
_ carries blood anteriorly
_ carries blood posteriorly - vertebrates, ventral aorta, dorsal aorta
- amphioxus exchange gasses via _
- diffusion
- in the amphioxus gases are exchanged between the water and vessels of the _ within the pharyngeal bars
- pharyngeal complexes of blood vessels