Reading guide for exam 3
Chapter 16, 17 – Digestive system – pp. 532-540, 549, 553, Fig 16-16, 557-569
Not responsible for details on digestive system development beyond Fig. 16-1, although you should know
that the gut tube and its derivatives (lungs, liver, pancreas) develop from endoderm. Not responsible for
tooth development. Know basic parts of tooth (root, crown, dentin, enamel, cement). Know acrodont vs.
theodont tooth attachment. Know polyphyodont vs. diphyodont, homodont vs. heterodont. Know
differential wear of teeth, why mammals want teeth to stay rooted. Know rooted vs rootless teeth in
mammals. There are many terms for different cusps on molars (protocone, hypoconid, etc.) that you will
not be responsible for – although it is admirable to see how mammalogists follow the evolution of the
different cusps in different mammals, and it also helps explain the difference between lophodont and
selenodont molars. Not responsible for dental formulas although you should know basic placental vs.
marsupial plan. Know bunodont enamel pattern vs. herbivore exposed dentin and enamel. Know
carnassial. At the top of p. 549 starts a good section explaining use of different muscles for mastication,
and herbivore vs. carnivore differences. The jaw hinge compared to tooth row differences for herb. vs.
carn. is explained in respect to lever arms for the different muscles they use. You should still understand
hard/soft palate but not responsible for vomeronasal organ (we’ll learn that later). Not responsible for
thymus and tonsils. Should know basic gut tube structure but not other details beyond what was discussed
in lecture (i.e. not goblet cells, valves of Kerckring, crypts of Lieberkuhn). The rest of the chapter is
organized by gut tube regions from mouth to anus. Know esophagus and stomach specializations. You
should know about basic gastric secretions from previous classes. Know cow stomach chambers and their
function. I won’t ask about specific digestive enzymes (lipases, disaccharidases, trypsin, etc.), facilitated
diffusion, cotransport. Know hindgut vs. foregut fermenters – Focus 17-2 compares those approaches.
Chapter 18 – Respiratory System – 575-581, Figs. 18-5, 18-6, 584-599
The first section of the chapter corresponds to my initial discussion in class – the ways to generally
increase diffusion of gasses across a membrane. Then the chapter divides into sections on our different
vertebrate groups, which includes info that we had before in lecture and lab (septal gills, respiratory tube,
gill lamellae, spiracle etc.) read this info to help review the three differences in fish gill structure. Know
new information is how fish move water over gills (suction/force pump of sharks and bony fish) and how
the physioclistous swim bladder works (gas gland, rete mirable, etc.). Remember countercurrent flow and
its advantages at gills. I used Fig. 18-8 to show accessory respiratory organs that store air in fish. Know
basic respiratory anatomy of tetrapods (lungs, trachea, larynx, bronchi, etc.), differences in lung anatomy
to change surface area (aveoli, septa). Know how gas/air/swim bladder is associated with lungs. Know
how original lung pocket along gut evolved early in fish – and how these were later modified to be
buoyancy structures. Know physoclistous vs. physostomous. Know what Fig. 18-11 shows and how the
physoclistous swim bladder is able to take oxygen from blood with rete mirable, gas gland, countercurrent
multiplier system. Know how frogs, birds, crocodiles and mammals ventilate their lungs and how
ventilation helps diffusion. Not responsible for extra anatomy details (such as arytenoid cartilage,
mesobronchus, mediodorsal bronchi..) Know
bidirectional vs. unidirectional ventilation of mammals and birds. Understand larynx position of humans
vs. other mammals.
Chapter 19 - Circulatory system – pp. 603-607, 608-611, 612-619, 622-623, portal systems
Not responsible for details on spleen (starting on p. 603) beyond what was discussed in class. Should
know physiological differences between arteries and veins. P. 607 introduces ventral aorta, dorsal aorta,
aortic arches. Notice the change in circulation from single pump to double pump during tetrapod
development, and the reduction of ‘fishy’ heart structures like sinus venosus and conus arteriosus.
Understand differences in shark vs. bony fish hearts and basic aortic arch pattern in fish. Not responsible
for venous system section p.611. Starting on p. 612 there is discussion aortic arch patterns, which serves
as a basis of comparison between them. Know fig. 19-9. I wouldn't worry about vessels or structures
mentioned in the book that I didn't bring up in lecture (eg: pulmocutaeous artery of frogs, cavum
arteriosum, venosum and pulmonale of turtle heart). Know parts of truncus arteriosus (pulmonary, left
systemic, right systemic). You should understand the shunts in a basic reptile heart and crocodile heart
and the anatomy involved. Just saying ‘there is a right to left shunt’ is not informative..explain anatomy
Know similaries and differences in birds/mammals. Not responsible for Fig. 19-15 or synapomorphies on
p.621. Know fetal circulation in mammals/birds/reptiles..we used mammals as an example in class. Know
neonatal circulation difference along ductus arteriosus. Know functions of renal and hepatic portal
systems. Other than that, not responsible for other information on venous system.
Helpful things to know for exam 3:
Digestion:
Know basic functions of the digestive system – where does the alimentary canal derive from? What other
things come from endoderm?
What is ram feeding vs suction feeding in fish?
Teeth are generally seen in vertebrates, what vertebrates don’t have them?
Know basic form of teeth: dentin, enamel, cement. Crown vs. root
Remember that teeth form from an interaction of dermis and epidermis with influence from neural crest
cells. Enamel organ from epidermis
Know acrodont vs. thecodont tooth attachment, what organisms have these?
Know polyphyodont vs diphyodont tooth replacement, what organisms have these?
Know homodont vs. heterodont dentition, what organisms have these?
Why have both dentin and enamel exposed along the top of teeth? What organisms have this?
Know rooted vs. rootless teeth in mammals, what organisms have these? Why?
What are the 4 types of teeth in mammals? Where are they found in the mouth? Know primitive
placental mammal dentary plan 3:1:4:3 and how dental plans can be changed from this plan
What is the difference between molars vs. premolars?
Know differences between the teeth of herbivorous vs. carnivorous mammals and why they have them.
What do carnassials do and how do they work?
Know bunodont vs. herbivorous dentition, what organisms have these?
What is the function of oral glands and what vertebrates have them? Name a few. How is the venom
gland related to oral glands?
Know insertions, origins of masseter vs. temporalis. What mammals emphasize which muscle? How do
they have a skull or jaw design to enhance the force of masseter vs. temporalis? Are they trying to
increase or decrease their in-lever?
How does being endothermic select for features of the digestive system? How important is physical
digestion?
What are the 4 basic layers of the alimentary canal?
Why have a keratinized esophagus? What does the esophagus basically do?
What is the function and design of a crop in birds? Why do seed-eating birds depend on a crop in caring
for young?
What generally happens in a vertebrate stomach? What is released into the stomach. What does chitinase
do?, pepsinogen? HCl?
What does the pyloric valve do? Where is it?
What are the regions of the small intestine? How are they basically different?
Know stomach modifications: pyloric cecae, inflatable diverticulum, gizzard. What is the function of a
gizzard? What organisms have a gizzard?
What issues do herbivores face when eating leaves and grasses made mostly of cellulose? What are the
two main types of ‘solutions’ to these issues? What is the role of bacteria/ microbes for those with a
herbivorous diet?
What is the basic anatomy of foregut and hindgut fermenters? Give examples of organisms in each
category. What are the functions of the chambers of a ruminant (foregut) stomach? Where are
bacteria/microbes housed? What do the microbes do? Where is absorption of nutrients? What advantages
do ruminants have over hindgut fermenters? Who has more complete physical digestion? Who has the
advantage when only poor quality food is available? Why? How can hindgut fermenters make up for
their disadvantage in extracting more nutrients from food vs. ruminants if there is high quantity of food?
What happens in a cecum in an herbivore? Do any birds have ruminant stomachs or cecums? What range
of body sizes are possible with a ruminant style of digestion? Explain.
Where is the ileocecal valve and what does it do? What are the regions of the large intestine?
What is coprophagy and how can it help some kinds of herbivores?
Respiration:
What are the three main factors that influence the diffusion of gasses into/from blood (from Fick’s Law)?
How can respiratory anatomy be modified in regard to these factors to enhance gas diffusion? What does
countercurrent exchange do to help diffusion? What does ventilation do to help diffusion?
What are the anatomical differences between septal vs. opercular gills?
How do sharks vs. bony fish use negative pressure and positive pressure to move water over their gills?
What anatomy is involved? What applies positive pressure?
What other anatomy can be used as a respiratory surface in water? Why would fish need to use
something other than just gills?
Where is there a higher concentration of oxygen: dissolved in water or in the air?
In regard to lungs for respiration vs swim bladders, which anatomy evolved first? Why was it needed?
How can lungs be modified to better be used for respiration? How can lungs be modified for buoyancy?
Contrast physostomous vs. physoclistous swim bladders. Which is ancestral and which is derived? What
advantage is there in the derived style? What group has this derived style?
What is a glottis, where is it found? Who has one?
How does gas get into a physoclistous swim bladder? How does the oxygen gradient cause difficulties in
having oxygen leave blood to the swim bladder? What structures help cause oxygen to diffuse into a
physoclistous swim bladder – how do they work?
What methods do amphibians use for their respiration? How does their vocal sac help in vocalizations?
What type of respiratory surface would not function in amniotes but does in amphibians? What anatomy
is found in amniotes but not frogs (think skeletal anatomy) and also think about amniotes having necks.
How can the liver help in respiration in alligators/crocodiles?
How are sprawled limb vertebrates at a disadvantage when moving and using lungs to breathe? How does
their locomotion compromise breathing? How do mammals not have this issue? What about aquatic
mammals..do they have lateral bending issues?
How are air sacs involved with the respiration of birds? Do they expand? If they do, how? Why are air
sacs helpful in the highly efficient respiration that birds have? (they are not respiratory surfaces) How can
uncinated processes of the ribs help?
What is a syrinx, what organisms have them? What happens in a syrinx? How can birds make two notes
at a time?
Where is an epiglottis or larynx or glottis found in mammals? What does the epiglottis do? How does the
soft palate help the epiglottis do its job? How is the anatomy of humans different in this regard? Why is
it important for us to be different in this way?
What is bidirectional vs. unidirection ventilation? What organisms have bidirectional ventilation of air or
water? Unidirectional? Is there an advantage to one style?
What do external intercostals, internal intercostals, diaphragm do to help ventilation? Which are used for
inspiration?
Circulation:
Where is pericardium? What is in pericardium? What is myocardium?
What is different in regard to elastic capabilities of arteries and veins? Where is most blood found under
typical circumstances? What do muscles in arterioles and venules do?
Explain the outcome of elastic recoil of large arteries considering downstream blood pressure. How does
recoil help?
What is single circuit vs. dual circuit circulation? Give organisms for each. What changes to the heart are
needed when there is dual circuit circulation?
What are embryonic aortic arches? Where is the ventral and dorsal aorta in regard to the aortic arches?
Can you describe or draw them? Why are comparative anatomists interested in them?
What chambers of the heart are found in Chondrichthyian fish? In bony fish? What is different about a
bulbus arteriosus vs. conus arteriosus? What circulatory anatomy do the aortic arches become in a fish?
What type of blood (oxygenated, deoxygenated or both) flows within a typical fish heart?
What happens to aortic arch 1, 2, 3, 4, 5, and 6 in tetrapods? What happens to the sinus venosus? What is
a truncus arteriosus?
Know how oxygenated vs. deoxygenated blood flows in lungfish, typical reptile, frog, and alligator
hearts. What changes when they aren’t ventilating their lungs? How does blood flow now? What causes
the blood flow to change when there isn’t ventilation? Know relevant anatomy such as: spiral valve, right
systemic, left systemic, foramen of Panizza.
How are the aortic arches generally different for a larval frog and an adult frog?
What circulatory anatomy is different in endothermic vertebrates? What does one-sided systemic mean?
Where does deoxygenated blood typically enter a mammal heart? What vessel does this blood leave the
heart? Where does it go? Where does blood from the lungs typically enter a mammal heart?
How is circulation different in a fetal mammal, reptile or bird (all 3 are the same) compared to an adult?
What is the ductus venosus, ductus arteriosus, foramen ovale? What do these structures do in fetal
amniote circulation – where in circulation are they located? What happens to them once the baby amniote
is born/hatches?
What is a portal vein? What is the function of the hepatic portal system? What organisms have a hepatic
portal system? Renal portal system?
Sample questions:
Blood can leave the right ventricle of an alligator and flow directly into what two possible destinations
(large arteries)? ________________________________ and ________________________________
2. Compared to the walls of veins, arterial walls are different in that they have many ________________
fibers.
3. Dentin of teeth will wear away _____________________________ than enamel (when both are
exposed at the surface of teeth). (1 point)
4. Mammals have teeth that vary from those of other vertebrates in that they are
____________________________________ and ___________________________________________
(give two ways they differ)
5. Air sacs in birds are expanded via the movement of _____________________________________
6. When a bony fish draws in water for ventilation, it will open / close (circle one) its operculum while it
relaxes branchial muscles to expand its mouth cavity. (1 point)
7. Cells on the inner lining of the stomach release _____________________________ into the stomach.
(give one thing)
8. What did your third aortic arch become while you developed?________________________________
9. Name a mammal with bunodont style teeth _______________________________________________
10. Most chemical digestion and nutrient absorption occurs in the lengthy ________________________
region of the small intestine.
11. The _________________ is a chamber of a ruminant herbivore that releases pepsinogen and acid like
a traditional stomach.
12. The _________________________ is a special notched tooth found in carnivores such as cats.
13. The renal portal vein carries blood from hindlimbs and brings it to ____________________
Answers:
1. right systemic and left systemic 2. elastic 3. faster 4. Heterodont, diphyodont, thecodont 5. Rib cage
or sternum 6. close 7. HCl or pepsinogen or mucus 8. carotid artery 9. Dog, cat, bear, human, pig, etc
10. ileum 11. abomasum 12. carnassial 13. the kidney
(7 points) Describe main aspects of anatomy of a mammal that is the most thorough in extracting energy
from fibrous leaves and grasses. Include A) an aspect of teeth and B) a description of their digestive
anatomy (along gut) and how it allows them to extract energy so well.
(7 points) What are the regions of a cow’s stomach? Give an advantage and a
disadvantage of digestion via a ruminent stomach.
(8 points) a) Contrast two main anatomical differences between physoclistous and
physostomous swim bladders in fish. b) What type of swim bladder would you expect to see in
a deep water fish? c) What is the form and function of the rete mirable?
(5 points) Most mammals are able to eat and breathe at the same. However, it is difficult for
humans to do this. What is different in human anatomy and why are humans designed this way?
(6 points) Name three different ways to encourage gas exchange. Identify specific structures or
modifications found in tetrapods that illustrate each of the three ways
(5 points) What is the functional significance of the ductus arteriosus?
(3 points) What is the fate of the third and fifth aortic arches in tetrapods?
(7 points) What structures are used in the frog heart to keep oxygenated and deoxygenated
blood separate? How do the structures function?