Laboratory 12
Zoology 1121
Phylum Chordata
Quiz
This Lecture is over 3 chapters:
12 (1) the Lancelet
13 (1-2) the frog (amphibian)
14 (1-2) the fetal Pig (mammal)
First some general information on the Phylum that contains all 3 then
dissection information on external and internal anatomy of all 3.
I. Phylum Chordata
Subphylum Urochordata & Cephalochordata
1. lots of radiation into all environments (land, water, air)
2. diversity is amazing
3. hard to determine P. Chordata sometimes unless look at its embryonic
development
4. three subphylum
a. Urochordata probably
the oldest phylogenetically
b. Cephalochordata
c. Vertebrata
5. Adult Urochordata are odd in that they are free-swimming larvae
but sessile adults
6. Monophyletic Group meaning possessing one common ancestor.
7. Neoteny when one group achieves sexual maturity before others
in the group.
8. Hypothesis chordata origin had some motile larvae attained sexual
maturity before they reached the sessile adult
form stage of life.
9. It was these motile larvae that radiated into the chordates (i.e.,
Urochordata, Cephalochordata, and Vertebrata)
10. Also can find all 4 of the phylum characteristics in Urochordata
as well as other 2 subphylums
Classification
1. Phylum Chordata
a. Notochord (a small flexible
supportive rod that runs longitudinally through the dorsal side)
b. Dorsal Hollow nerve Cord
(its dorsal to the notochord)
c. Pharyngeal Gill Slits
(slits lie between the oral cavity and the esophagus)
d. Post-anal tail
2. Subphylum Classification based on Notochord (N) and Never Chord
(NC)
a. N-NC present only in
larvae; adult sessile . . . . . . . . . . . . . . . . . . . . . .
.SP Uro.
b. N-NC present in both
larva and adult . . . . . . . . . . . . . . . . . . . . . . . ..
. . SP Ceph.
c. N incorporated into a
vertebra, NC encased in bone . . . . . . . . . . . . . . .. .SP Verts.
II. Subphylum Urochordata
1. sea squirts
2. dont have to know these, but a good read though
III. Subphylum Cephalochordata
1. common name for Lancelets
2. only two main genera with about 30 representative species
3. marine organisms
Lancelet Systems Subphylum Cephalochordata [No Class for this]
[Be able to trace these from start to finish from memory]
IV. Digestive System of Lancelet
1. Rostrum most anterior end
2. Vestibule hollow area behind the rostrum
3. Mouth opens off the vestibule. (Note again, mouth after vestibule
not before)
4. Wheel organ acts to pump water into the vestibule
5. Pharynx
6. Gill Slits perforations into the pharynx part of the digestive
system
7. Gill Bars act as filters from water moving through the gill slits
8. Atrium a membrane structure that actually surrounds the pharynx
9. Atriopore - a hole in the atrium that strains out water
10. Intestine
11. Cecum a shunt off of the intestines (see this in most all Phylum
Chordata even mammals)
12. Anus
13. Keep in mind we have both water and food entering the mouth but
the water leaves through the pharyngeal slits and
food leaves the anus
V. Respiratory System of Lancelet
1. Water that enters also contains dissolved oxygen as well as food
when enters the mouth
2. Gas exchange happens at gill slits
3. Thus gill slits serve two functions (systems): Digestive and respiration
4. deoxy water leaves via the atriopore
VI. Circulation System of Lancelet
1. Closed system of vessels
2. No distinct heart for pumping the blood
3. Ventral Aorta acts as the heart by peristaltic contractions
4. Arteries branch away from aorta and further help pumps deoxy blood
5. Arteries goes into a capillary bed (aka, cap bed)
6. Arteries leave cap bed not as veins but as efferent arteries and
refuse together into a fused pair of dorsal aortas (aortae
= plural of aorta) on each side of the pharynx.
7. DA carried oxy blood to posterior region.
8. Large veins return to ventral aorta
VII. Skeletal & Muscular of Lancelet
1. Notochord lies immediately dorsal to digestive system
2. Notochord is endoskeleton element
3. Notochord is flexible but hard rod that muscles use for contraction
points
4. Myomeres these are V-shaped muscles in Lancelet
5. The notochord prevents the folding of the body when the myomeres
contract
VIII. Nervous System of Lancelet
1. Dorsal nerve cord (NC)
2. Anterior end has cephalization (remember the lancelet is bilaterally
sym.)
3. Anterior NC slightly expands out into a brain
4. Spinal nerves branch out from the NC to innervate the myomeres
5. Note:
a. Innervate when a nerve
makes contact with any other structure than a neuron.
b. Enervate to deprive
of strength, to weaken, has nothing to do with neurons.
IX. Excretory System of Lancelet
1. Nephridia ciliated tubules similar to ones with earthworms
2. Cilia beat to draw in the fluid.
3. Has closed end that makes contact with coelomic fluid and absorbs
waste.
4. Have a collecting duct at opposite ends of tubules to the cilia
and opens by means of a pore into the atrium.
5. Note: this isnt like humans where filtration is through the blood,
instead its through coelomic fluid
X. Reproductive System of Lancelet
1. Dioecious
2. Gonads in the atrium and anterior to the atriopore
3. Gametes come out through the atriopore.
4. Thus, atriopore used in 3 systems:
a. digestive
b. circulatory
c. reproduction
Frog Systems Class Amphibia
1. Be able to trace these from start to finish from memory
2. read lab manual on vertebrate evolution
3. read section on phylogeny and be able to produce tree of 13-1
from memory
4. Read classification schema as well
I. External Anatomy of Frog
1. Rana pipens is Genus species name
2. More than half the respiration goes through the frogs skin
3. Thus, skin must be moist (remember, oxygen must dissolve into water
(or some fluid) before it can go to circ. systems)
4. Specialized glands to help keep it moist
5. Dorsal side dark and ventral side light (to evade predators from
above and below)
6. Segmented body into: head & trunk
7. Eyes
8. Nostrils
9. Tympanic membranes spans a canal for hearing. The membrane vibrates.
First time we see hearing (acoustic) as a
sense function
10. Paired appendages: one set anterior (arms) and one set posterior
(legs)
Internal Anatomy
II. Skeletal System of Frog
1. Skeleton is internal framework
2. Two divisions of a skeleton system (not just in frogs)
a. Axial runs in one straight line from the skull downward
b. Appendicular runs away from the axial
3. Axial contains the skull and vertebra
4. Appendicular includes all the bones that make up the limbs (both
fore and hind) and the two structures that attach the
limbs to the axial skeleton.
a. Pectoral Girdle attaches
the forelimbs to the axial skeleton
b. Pelvic Girdle attaches
the hind-limbs to the axial skeleton
5. 9 vertebrae plus 1 urostyle makes up the frogs vertebral column
6. A specialized vertebrae articulates (articulates means a place where
of two bones connect) the skull to the column. It is
called an atlas.
To remember this think of the Greek God who held up the world.
7. No ribs coming off the vertebra as we see in mammals
8. Urostyle part of the pelvic girdle and probably a fusion of vertebra
9. The Pectoral Girdles articulates the forelimbs to the vertebral
column (VC) and has two sides.
a. dorsal scapulas and
suprascapulas
b. ventral clavicles (i.e.,
collarbones)
10. The Pelvic Girdle articulates the hindlimbs to the VC.
11. Pelvis consists of three bones (usually same for mammals as well)
a. pubis
b. ischium
c. ilium
12. ischium and ilium are fused together
III. Muscular System of Frog
1. muscles of the frog used in all types of movements (from movement
of frog to movement of food down the digestive tract)
2. three types of muscles here
a. skeletal (aka, striated)
moves the endoskeleton, under voluntary control
b. smooth usually found
in viscera (i.e., the inside muscles of the major systems) and under involuntary
control
c. heart (cardiac) specialized
involuntary muscles type only found in heart
IV. Digestive System of Frog
1. Mouth is opening to DS
2. Buccal Cavity is a cavity found after the mouth
3. Two openings to Pharynx
a. Esophagus opening to
the digestive system
b. Glottis opening to
respiratory system (also contains larynx, or voice box)
4. Esophagus goes directly to the stomach
5. The stomach has two valves that prevents all the food from
rushing through it
a. cardiac valve where
the esophagus meets the stomach
b. pyloric valve where
the end of the stomach meets the duodenum
6. The Bile duct shoots off the posterior end of the stomach (before
the pyloric valve) and is a passageway that goes to the
gall bladder.
7. The liver does a number of things (mainly detoxify foods) but also
produces a substance known as bile. Bile acts to
emulsify fats, that is,
wraps the fats produced from digestion into a coating. The liver
makes this bile and then holds it
in the gall bladder until
its needed during digestion.
8. Another gland secretes materials into the bile duct and hence into
the stomach. Its called the pancreas.
9. After the stomach is the small intestines
10. Small intestines has two divisions, in order:
a. duodenum
b. ilium
11. After the small intestines comes the Large Intestines
12. Large intestines main function is for re-absorption of water from
the food products moving through the digestive
system thats why its
so long.
13. LI then turns into the rectum and the cloaca
14. Mesenteries (pronounced mez-in-tare-ezes are clear tissues
that hold the parts of the stomach together and keeps
them from folding in and
over its self and getting tangles up into a knot.
15. Other systems (excretory and reproductive) have ductwork that opens
into the cloaca
V. Reproductive System of the Frog
1. Underneath the huge liver are the lungs
2. The larynx (which comes off the glottis from the mouth) divides
into two branches called bronchi
3. Each bronchus leads into a lung
4. The bronchi further branches down into smaller structures such as
the bronchioles and the alveoli, which are commonly
know as the air sacs.
VI. Circulatory System of the Frog
1. function of the CS is to provide an efficient means of distribution
for exchange of products (wastes, oxygen, nitrogen, etc)
2. Closed network of vessels with a pump to keep fluid in motion.
3. Arteries carry fluid away from heart (most terms for this function
will look similar to this word. I.e., Aorta is
major artery)
4. Veins - carry fluid towards the heart (most terms for this function
will look similar to this word. I.e., Vena Cava is
major vein)
5. Arteries and veins meet in a area known as capillaries (aka, a capillary
bed)
6. Diffusion of cellular products from the CS are exchanges in the
cap beds since the walls of the arteries and veins are
too thick
7. Heart has 3 main divisions.
a. Right Atrium
b. Left Atrium
c. Ventricle
8. Note the number of divisions of heart is dependent on the Class
you look at. For example, mammals have 4 divisions of
the heart.
VII. Lymphatic System of the Frog
1. Cellular products of the circulatory system diffuse through the
walls of the capillaries.
2. However, these products can sometimes collect into the capillary
beds causing swelling (called edema) or low blood
pressure.
3. The lymphatic system is a system of ducts that function to drain
these cap beds of products
4. This system then returns the products to the veins of the circulatory
system.
5. The lymphatic system contains its own type of moving fluid called
lymph
6. Think: lymph is to the lymphatic system as blood is to the circulatory
system)
7. Two pairs of lymph hearts control movement of the lymph.
a. one pair by the 3rd vertebra
pumps lymph into jugular vein
b. second pair at end of
VC pumps lymph into iliac vein in the legs
VIII. Excretory System of the Frog
1. The kidneys are the main units of the excretory system
2. Kidneys lie dorsal to the coelomic cavity
3. They filter nitrogenous waste from the blood and maintain water/osmotic
balance of the body
4. The two kidneys lie on either side of the dorsal aorta. It serves
as a cap bed and as such has its own arteries and veins
from the aorta. Known
as renal arteries to the kidneys and renal veins away from the kidneys
5. Urine is a product made in thew kidneys and consists of nitrogenous
wastes among other things
6. The ureter is a thin walled tube that runs posteriorly off the kidneys
and into the cloaca
7. After urine is released into the cloaca it is held temporarily in
a bladder
8. The bladder further re-absorbs water from the urine
9. Urine is then released again into the cloaca after concentration
in the bladder back into the cloaca for release into the
environment
10. Fat Bodies attached to the anterior portion of the kidneys and
are used as a food source during winter
11. A ventral gland next to the kidney are the adrenal glands
12. These adrenals dont function in excretory but rather in the endocrine
system and synthesize hormones such as
epinephrine, norepinephrine,
and corticosterone.
IX. Reproductive System of the Frog
Male
1. Testes are small structures ventral to the kidney and connect to
the ureter by small ducts
2. These ducts carry the sperm made into the testes
3. Sperm is released with urine from the cloaca
4. Another name for the ureter is the mesonephric duct
5. Notice that in the male the reproductive and the excretory system
share the same tubules
Female
1. The female has ovaries and own passageway into the cloaca called
the oviduct
2. The ovaries are attached to the body wall and not the kidneys as
are the testes are
3. The anterior end of the oviduct is an opening called an ostium
4. The oviduct runs posteriorly and becomes the uterus before attachment
to the cloaca
5. The ovaries produces eggs into the coelomic fluid and these eggs
are pulled into the ostium and down the oviduct to the
uterus where they are stored
for release in external fertilization
6. Notice then that unlike the males, the female system uses its own
duct work to empty its gametes into the environment
X. Nervous System of the Frog
1. Read through his information in the text, but no dissection info
over this on the test
2. It is a fascinating read
Fetal Pig Systems Class Mammalia
1. Be able to trace these from start to finish from memory
2. read lab manual on vertebrate evolution
I. External Anatomy of the Pig
1. Sus scrofa
2. Segmented into: head, neck, trunk (thorax and abdomen), and tail
3. Lips
4. Nares the 2 openings of the nose
5. Eyelids upper and lower
6. Umbilical cord
7. Digitigraded means they walk on their digits (i.e., toes)
8. Urogenital opening
a. males directly posterior
to the umbilical cord
b. females next to anus
and covered by the genital papilla
9. Mammary papillae both sexes have and are developed beore sex determination
occurs. Much the same way human
males have nipples. They are per-cursors to the mammary glands, which form
later on.
10. Oral Cavity teeth, tongue, hard & soft palate
11. Two holes next to each other for different systems
a. esophagus opening to
digestive tract
b. glottis opening to
the respiratory system
12. Epiglottis circular flap of skin that covers the glottis
Internal Anatomy
II. Skeletal System of the Pig
1. All vertebrates conform to similar design
2. Axial and appendicular skeletal systems
3. Articulations where two bones meet also known as a joint
4. Six different types of joints
a. Sutures these are only
joints that are immovable (in skull)
b. Compression Joints
c. Gliding Joints
d. Hinge Joints
e. Pivot Joints
f. Ball-and-socket Joints
III. Muscular System of the Pig
1. Terminology
a. Origin and Insertion
the bones to which the muscle is attatched at each end
b. Type of Articulation
between the muscle and the bone (e.g., tendons)
c. Action of Movement
1. flexion
2. extension
3. adduction towards the midline
4. abduction away from the midline
5. rotation
IV. Digestive System of the Pig
1. Mouth is first part of digestive system (DS)
2. Teeth mechanical breakdown of food
3. Salivary glands add enzymes to break down the food
a. Amylase the enzyme
being produced
4. Thus digestion actually starts in the mouth
5. Esophagus
6. Smooth muscles ring the esophagus and the digestive system and involuntarily
control digestion
7. Stomach highly ridged with villi (both macro- and micro-)
8. Has glandular cells in this lining
a. one type produces the
product called pepsin
b. another produces hydrochloric
acid
9. Cardiac Sphincter valve between esophagus and stomach
10. Pyloric Sphincter valve between stomach and duodenum (i.e., small
intestines)
11. Small Intestines 3 divisions
a. Duodenum receives ductwork
from both liver and pancreas
b. jejunum
c. ilium
12. Liver makes bile and detoxifies blood
13. Connected from duodenum by the bile duct is the Gall Bladder, located
just underneath the left liver lobe. Each liver
lobe (there are 4) makes
bile and secretes it into the duct where it can be stored in the GB for
use during digestion
14. Gall Bladder stores the bile made in the liver
15. Bile acts to emulsify fats
16. Pancreas diffuse glandular structure embedded in the mesenteries
that support the stomach and intestines
17. Pancreas produces two end-products
a. enzymes used in digestion
b. hormones secreted into
the circulatory system (specifically the hepatic portal system)
18. Cecum blind pouch right at the connection between the small and
large intestines.
19. Cecum primarily a storage organ holds bacteria that further
help breakdown indigestible food. Humans reduced
to vestigial appendix
20. Colon another name for the large intestines primarily responsible
for absorbing water from the food bolus traveling
through the DS
21. Rectum
22. Anal sphincter muscle controls movement of feces out the anus
23. Mesenteries
V. Excretory System of the Pig
1. Homeostasis the regulating of internal processes (think of a balancing
act)
2. One important homeostatic process is the elimination of toxic metabolic
by-products
3. Two toxic by-products of metabolism
a. carbon dioxide eliminated
by circulatory system (and eliminated via resp. sys)
b. nitrogen eliminated
by excretory system
4. Regulation of ion concentrations (sodium, potassium, etc) and water
concentrations are dually handles by
excretory and circulatory system
5. Kidneys the main units of nitrogenous waste removal
6. These are against the dorsal wall of the abdominal cavity and are
intimately connected to the circulatory system via the
renal art/veins
7. Kidney also function in excess water, salts, and other substances
8. Hilus connection between the art/veins and the kidney
9. Ureter runs posterior from kidneys
10. Bladder holds the urine and further concentrates it
11. Urethra urine leave via this duct from the bladder
12. Remember order :
kidney > ureter
-> bladder > then the urethra
VI. Reproductive System of the Pig
1. Note here there is also a difference between the ductwork in a male
and female. Males- share structures with excretory
system. Females dont
share.
Male
1. Scrotal sacs hold the testis
2. Internal testis
a. seminiferous tubules
produce the sperm
b. epididymus - storage
site after sperm produced
c. vas (ductus) deferens
discharge tubule
d. urethra common ductwork
the excretory and reproductive system share
3. Semen mixture of sperm gametes and fluid suspension
4. Several Glands make the semen
a. Prostate Gland
b. Semianl Vessicles
c. Cowpers Gland (aka, Bulbourethra)
5. Penis
Female
1. Ovaries produces gametes
2. Ova (aka, eggs) erupt from ovary and captured by fallopian tube
(aka, oviduct)
3. Taken to the uterus
4. Branched horns uterus meets up together
5. Vagina each horn opens into the vagina
6. Vagina opens directly to outside environment
7. Internal fertilization in mammals
a. sperm is injected into
vagina by male penis
b. sperm swims up the oviduct
and meet with ovum
VII. Respiratory System of the Pig
1. Main functional units of the respiratory system are the;
a. lungs
b. heart
2. epiglottis
3. glottis
4. larynx
5. tracheae
6. bronchus primary and secondary
7. bronchioles
8. terminal bronchioles
9. respiratory bronchioles
10. alveoli highly vascularized and site of gas exchange
VIII. Circulatory System of the Pig
1. Heart main functional organ of the circulatory system
2. Heart covered in a thick membrane called a pericardial sac
3. Heart has 4 chambers
a. 2 atria
b. 2 ventricles
4. allows for double circulation to the lungs and the body with NO
mixing between the oxy and deoxy blood
5. Spleen functions in the storage and release of blood cells made
elsewhere
6. Aorta major artery in mammalian body
7. Aorta leaves the LV of the heart as the aortic arch then runs posteriorly
and dorsaly following the VC as the dorsal aorta
8. Veins one-way valves inside prevent back-flow of blood. Lower
blood pressure than arteries because the are after the
cap beds
9. Pulmonary trunk (aka, pulmonary arch)
10. Divides into left / right pulmonary arteries to the lungs carrying
deoxy blood
11. From lungs via pulmonary veins back to the heart
Circulatory Blood Flow through heart
1. Anterior Systemic + Posterior Systemic
2. Anterior Vena Cava + Posterior VC
3. Right atrium
4. Right Ventricle
5. Pulmonary trunk
6. L/R pulmonary Arteries
7. Lungs
8. L/R pulmonary Veins
9. Left Atrium
10. Left Ventricles
11. Aortic Arch
12. Dorsal Aorta
13. Anterior Systemic + Posterior Systemic
14. Major veins of Anterior Vena Cava
1. Subclavian vein from
thoracic and arms
2. Internal Jugular Vein
from tracheae, larynx, neck and brain
3. External Jugular Vein
from head and shoulders
15. Major Veins of the Posterior Vena Cava
1. Hepatic Vein from 4
lobes of liver and diaphragm
2. Renal Vein from kidneys,
adrenals, gonads
3. Common Iliac Veins
from abdominal wall. Tail, pelvis and legs
16. Hepatic Portal System embedded in the mesenteries
17. Portal System :
artery cap bed portal cap bed veins
IX. Nervous System
1. read and know basic structures