Lab 1: Lower Chlrdates and jawless Vertebrates Flashcards
Cranial, caudal, Rostral
Closer to head
Closer to tail
Structures just within the head (cranial)
Superior and inferior in humans
Dorsal, ventral
Closer to vertebral column or backbone
Closer to the belly
Posterior and anterior in humans
Lateral and medial
More to the side of the body
More towards the midline
Proximal and distal
Closer to point at which limb attaches to body
Further
Ex: elbow is proximal to the wrist because elbow is closer to shoulder than wrist. The wrist is distal to the elbow
Superficial and deeps
Lie closer to the skin surface
Sagittal plane
Midsagittal section
Parasagittal section
Passes through the body from dorsal to ventral (animals) from head to toe in humans
Divides the body into equal right and left halves
Sagittal section not in the midline
Frontal plane
A section made that divides the body into dorsal and ventral parts longitudinally.
For humans, this plane divides us into front and back halves. For quadrupeds, the frontal plane separates the back from the belly.
Transverse plane
Cross section
Divides into cranial and caudal parts
Chordate characteristics
Notochord
Dorsal tubular nerve cord
Post anal muscular tail
Pharyngeal hill slits
Sub pharyngeal gland (thyroid) that binds iodine
Hemichordates and example
Wormlike marine animals
-generally not considered chordates (true notochord in question)
Acorn worms- live in shallow coastal water and burrow into sand. Belong to genus Balanoglossus
Echinoderms
Sea stars and urchins
Chordates, hemichordates and echinoderms are all
Deuterostomes
Ambulacraria includes which groups
Echinoderms and hemichordates
Balanoglossus body can be divided into what regions
Proboscis
-conical anterior portion of body
-pushed forward during burrowing
-supported by stomochord (notochord analog)
Collar
-collar coelom inflates to anchor the work in its burrow, deflates when proboscis inflates to move.
Trunk
Stomochord
Near stalk or proboscis
-analogue if notochord
-partly chitinous, but walls consist of vacuolated cells which resemble the notochord.
Balanoglossus water enters the …. And exits the …..
Mouth and pharynx
Numerous dorsal pharyngeal gill slips
Slits empty into an atrium, space formed by lateral fold of body (genital folds)
In Balanoglossus, numerous external outpouchings of the ______ are evident in the anterior part of the intestine
Hepatic cecae
Balanoglossus have ______ gill slits
Internal
Urochordates (Tunicates)
-common name
-phylum
-mobility
Sea squirts
-chordates
-mainly sessile species
The contracted siphons of Urochordates (Tunicates) lie at the ______ which is the ______ surface.
The incurrent siphon is _______ at the _____ and the excurrent siphon lies more to the ______
Top
Dorsal
Larger
Top
Side
Urochordates (Tunicates) Tunic
Is leathery and is secreted by the epidermis cell layer, can be seen beneath the tunic
The anterior surface of Urochordates (Tunicates) is at the ______ and the posterior surface is at the _____
Incurrent siphon
Excurrent siphon
Mantle
Thin, transparent, Muscle Covering of organs in tunicates that helps contract to expel water from the pharynx
Most of the inside of Urochordates (Tunicates) is occupied by the ____
Pharynx
The gill slits of the pharynx are _____ shaped and the openings are lined with _______ to create a current that draws water through the slits in Urochordates (Tunicates)
Spiral shaped
Cilia
Urochordates (Tunicates) feeding style and how it works
Filter feeder
As water passes through the hill slits of the pharynx, food is captured by mucus strands sent out from the Endostyle, a thickened line on the ventral portion of the pharynx.
Eventually, the mucus strands with their trapped food particles are collected on the opposite side of the pharynx in a ciliated fold of the pharynx called the dorsal lamina. Strands are roped together in a spiral motion and passed to the digestive system.
Endostyle appearance in Urochordates (Tunicates)
U shaped
Inner lining has glandular mucus secreting cells and a long flagellum
Certain cells of the Endostyle produce____
Iodinated proteins
Likely homologous to thyroids gland in vertebrates
Only chordate characteristic of adult tunicates is…..
Pharyngeal slits and Endostyle
Tunicate larvae
-motile
-develop quickly
-after swimming for days, large attaches to a substrate and undergoes a metamorphosis.
-displays all chordate characteristics
-nerve cord expands anteriorly as an eyespot
-does not feed
-adhesive suckers at anterior end to stick to substrate
-once attached, nerve cord, notochord and tail atrophy
What are Cephalochordates
-size
-habitat
-common names
-reason for name
-mobility
Small, somewhat fish-like marine organism 4-7pm in length that are found in coastal waters of continental shelves.
-adults are sessile, partly in sandy substrate
-most common are lancelets or amphioxus
-notochord extends right into the front of the head.
-filter feed or swim weakly using myomeres and small caudal fin
Myomeres
V-shaped muscle segments
How many fins does amphioxus have
Dorsal fin
Ventral fin
Caudal fin
Oral hood
Transparent chamber at cranial end with Fringed with chemo receptive tentacles called oral cirri. Cirri also help exclude large food particles from the pharynx.
Contains the mouth
Amphioxus
Where are gonads on amphioxus
Are sexes separate?
Arranged in blocks below the myomeres
Yes but not distinguishable externally
The ______ of amphioxus extends the entire length of the body and can be contracted to increase its turgidity for swimming and burrowing
Notochord
In amphioxus, the ________ is dorsal to the _____, and is almost as long as the ______
Nerve cord
Notochord
Notochord
Pharynx
The walls of the pharynx of amphioxus have spaces called _____
Large chamber extending from the mouth to the intestine
Gill slits
The nerve chord in amphioxus is tubular (hollow) and has _________ along its ventral margin
Dark, photo receptive pigment spots
Does the pharynx have respiratory function in amphioxus
No, gas exchange occurs through the skin
Some Endostyle cells of amphioxus produce _____ and others _____
Mucus to trap food
Concentrate iodine
Are Cephalochordates or Urochordates our closest living relatives
Urochordates
Most primitive vertebrates alive today are the
Jawless vertebrates
Lampreys
Hagfishes
Ostracoderms are specialized in having a _________ while hagfishes and lampreys are ______
Bony armour
Slimy, eel like fish specialized for burrowing or parasitic lifestyles
Ostracoderms are more closely related to _____
Jawed vertebrates than hagfishes and lampreys
Hagfish appearance
-round mouth
-slimy
-sensory barbels around mouth
-external hill opening(s)
-single Neal opening
-scaleless skin
Hagfish habitat and diet
Marine
Burrows or bottom waters of continental shelves
Shrimp, polychaete worms and dead or drying fish and marine mammals
Hagfish defence
Secrete huge quantities of mucus and protein threads
Remove mucus after the threat is over by tying themselves in a knot and passing it along the body to squeeze off the mucus
Lampreys appearance
-found mouth
-slimy eel shape
-scaleless
-dermal bony armour
-up to 1 m
Lamprey lifestyle and habitat
External parasitic lifestyle
Temperate waters, travel up fresh water streams and rivers to breed (anadromous), some are land locked and live entirely in fresh water.
How are lampreys bodies divided
Head
-a tie or end and fill region
Trunk
Caudal regions
Caudal fin of lampreys are of the ______ type
Diphycercal
Vertebrae extend to the tip of the tail and the caudal sun is supported by fin raya above and below the axial skeleton
Lamprey
Buccal funnel
Annuals ring
Horny teeth
Buccal papillae
Tongue
Forms the mouth region in lampreys
-supported by a ring of cartilage, sun toon onto prey. internally called the annular ring
-interior funnel has many rows of brown horny teeth. Composed of heavily keratinized epithelium. Used to bite into prey.
-fringed margins of Berkeley’s Buccal
papillae. Sensory structures to achieve suction.
-rasping, protrubisble tongue in Center of mouth used for abrasion of the hosts flesh
Median Nostril of lamprey
On top of head and leads olfactory apparatus within.
Pineal organ or pineal eye
Lamprey
Lie beneath skin, which lacks pigment in this region. Not image forming but sensitive to light levels and plays a role in diurnal cycles such as colour change in larval lampreys.
Lateral eyes or lamprey
Well developed, lidless, image forming eyes.
Layers like system
Lamprey
Short rows of bumps or ores
Sensory system in fished which allows them to detect vibration and movement in the water
How many gill slits do lamprey have
7 external gill slits open externally behind the lateral eyes.
Cloaca
Chamber into which the anus and Urogenital ducts open
Urogenital papilla
Small finger-like tube which receives both excretory (nitrogenous wastes from kidney) and genital (egg or spermatids) products
Found within the cloacal chamber
The muscles of fish are arranged in segments called ______ separated by connective tissue partitions called _______
Myomeres (V shaped)
Myosepta
Contraction of the myomeres results in _______
Lateral bending of the trunk and tail
The tongue of lampreys is supported by
And is moved by
The Buccal cavity is supported internally by
A large lingual cartilage
Lingual muscle surrounding the cartilage
Annular cartilage
The main component of the axial skeleton of lampreys is the _____
What is its function
Notochord extending from the tail region to just beneath the middle of the brain.
Provide support during locomotion by preventing shortening of the body when myomeres contract
Arcualia
What are they homologous to
Small cartilaginous prices extended for Sally from the notochord to partially enclose the spinal cord
Thought to be homologous to vertebral arches of vertebrates
Chrondrocrabium
Purplish cartilage surrounding the brain of lampreys
Branchial basket
In lampreys, cartilage supporting the full region
Inner ear of lampreys location and specialization
Caudal to the eye and enclosed in cartilage on either side of the Brian
Has two vertical semicircular ducts instead of 3 like vertebrates
The pharyngeal glands of lampreys are surrounded by
Lingual muscles
Pharyngeal glands
Secrete their products beneath the tongue, to produce an anticoagulant that prevents clotting of the hosts blood. Also secrete enzymes to begin digestion if the preys proteins and blood cells.
Pleuroperitoneal cavity
Portion of the coelom containing the digestive organs such as the liver and intestine in lampreys
Spiral valve
In lampreys, a fold in the intestine that runs slightly spiralled and increase surface area
Why are lampreys intestines simple
Not mesentery holding it in place.
Simplicity due to fluid diet that is easy to digest and absorb compared to solid foods
Lamprey liver
When are the gall bladder and bile duct present
Large green organ, triangular in Sagittal
Larval phase only
Respiratory tube/ respiration in lampreys (normal) and parasitic
-guarded by a series of finger-like tentacles which constitutes the velum that prevents debris from harming the gills
-contains several internal hill slits which leads into the hill pouch or branchial pouch
-numerous gill lamellae are present in each pouch.
-water entering the mouth flows through the pharynx, respiratory tube and gill pouches then leaves through the external gill slits
When attached to a host, water enters and exits thought the external gill slits.
Blood and body fluids travelling through the mouth and pharynx are prevented from entering the respiratory tube by the velum
Lampreys have how many major parts of the heart
3
Atrium: on left, larger and darker
Ventricle: right, lighter, more muscular
Sinus venosus: tube between above two
All major veins of body eventually drain into the _______
Sinus venosus
Passageway of blood in heart
Deoxygenated blood-> sinus venosus->sinus trial aperature->atrium->atrioventricular aperature->ventricle-> ventral aorta->gills-> gas exchange in afferent branchial arteries->oxygenated blood in 7 pairs of efferent branchial arteries-> dorsal aorta->carotid arteries or caudal Artery or vein—> brain or tail-> vein into 2 posterior cardinal vein or anterior cardinal veins ——> sinus venosus
The caudal artery and caudal vein
The artery lies _____ to the vein
Dorsal
The anterior and posterior cardinal veins on the right side of the body _______ to form a _____
Unite
Right common cardinal vein which passes on the right side of the esophagus to enter the sinus venosus
Anterior cardinal veins drain the
Dorsal portion of the head and branchial regions
Inferior jugular vein drains
Usually paired ______
Ventral party of the head and brachial region are drained by this
Anteriorly until just cranial to the fifth hill slit where it becomes a single vessel which then drain into the sinus venosus, centrally and anteriorly
Lampreys lack a spleen, how does blood form?
In a specialized tissue called a hemopoietic tissue
Dark or cream coloured zone of connective tissue dorsal to the spinal cord and notochord
Lampreys have a primitive kidney called a _____
What is it drained by
Opisthonephros
Archinephric duct: collapsed, thin walled tube at the ventral edge of the kidney.
Urogenital sinus is formed by…
This leads outside of the body as the _____
Archinephric ducts from either side untie anterior to the cloaca to form this
Urogenital papilla
Gonad of lamprey
Very large: Nearly fils pleuroperioneal cavity
Ovary contains thousands of eggs
Teatis consist of gonadal tissue
Eggs and spleen are discharged into the coelom directly and leave the body via genital pores which are lateral to the Urogenital sinus.
Fertilization of lampreys is _____
External
Lamprey life cycle
Migrate from ocean to lakes to streams to spawn and then die. Larvae hatch in 3 weeks. Larval life lasts 5-7 years followed by metamorphosis at a length of 10-12 cm. Adult phase lasts 1-2 years before spawning
Ammocoetes sp. appearance
Lamprey larvae
-dorsal fin and caudal fin continuous
-post anal tail
-spinal cord visual as dorsal, dark staining structure running length of the larvae and into brain.
-notochord is lighter and ventral to spinal cord
-nostril cranial to eye
-auditory vesicle (large, clear)
Ammocoetes feeding
Filter feeding like amphioxus, lacks parasitism like adults.
Feeding accomplished by muscular pumping of water into the pharynx rather than by ciliary action (amphioxus). This more efficient= bigger size!
Sub pharyngeal gland
Ammocoetes
Homologous to Endostyle
Secretes mucous which is discharged into the pharynx via a duct. More mucous is produced by the pharyngeal lining and gill pouches. Mucous traps food and then forms a long cord which travels down the esophagus.
Some of the cells of the gland produce iodinated proteins and these cells are transformed into a thyroid gland of the adult.
Ammocoetes digestive pathway
Muscular pulling of water into pharynx, subpaheyngeal gland, esophagus, intestine, cloaca
Ammocoetes liver and gall bladder
Liver is squarish and contains a clear vesicle, the gall bladder.
Heart of Ammocoetes
Hollow sac in front of the liver and behind the branchial region
In Ammocoetes the spinal cord lies _______ to the notochord
The sun pharyngeal gland lies ______ the ventral aorta
Dorsal
Beneath
Lower chordate groups
Hemichordates
Urochordates
Cephalochordates
What 5 characteristics do living jawless vertebrates (hagfishes and lampreys) share with earliest known fossil vertebrates (ostracoderms)
Round mouth opening
Jawless
Lack appendages
Pharyngeal hill slits
Notochord
