Chapter 12 Part 3

Question 1

Describe basic anatomy of bird and mammal hearts

Answer 1

Both:
o Ascending aorta
o Left and right atrium
o Left and right ventricle

Question 2

Describe differences of bird and mammal hearts

Answer 2

Birds:
o Thicker walls between chambers
o Tend to have larger hearts than mammals (relative to body size and mass)
o Tend to pump more blood per unit time than mammalian hearts

Mammals:
o Smaller, thin pieces within chambers to split into sections

Question 3

Ventral aorta

Answer 3

carries deoxygenated blood from heart to 4th arch on bottom of arches

Question 4

Aortic arches

Answer 4

blood vessels associated with each gill or brachial arch

6 in total, varies from group to group in arches lost and arches kept, as well as arches modified to become something else

associated each with brachial arch

Question 5

Dorsal aortae (anterior)

Answer 5

paired with arches and carries oxygenated blood across top of arches

Question 6

Dorsal aortae (posterior)

Answer 6

singular thick tube that carries oxygenated blood

Question 7

Afferent branchial arteries

Answer 7

o Afferent vessels: heart to gills

Question 8

Pretrematic and posttrematic branches:

Answer 8

anterior and posterior halves of each collecting loop

Question 9

Efferent branchial arteries

Answer 9

Efferent vessels: gills to body

Question 10

Where do the four aortic arches come from?

Answer 10

ventral aorta; service gills associated with five pharyngeal slits

Question 11

Pharyngeal gill slits in sturgeons

Answer 11

the first pharyngeal slit persists as a small spiracle

Question 12

Pharyngeal in most fish

Answer 12

absent in the adult - The first aortic arch is lost along with this first slit

Question 13

How many functional gills do teleosts have?

Answer 13

four (pairs)

Question 14

Describe gills in Australian lungfish

Answer 14

o 1st pharyngeal slit reduced to a spiracle, associated aortic arch (I) also reduced
o ln the Australian lungfish (Neoceratodus): the remaining five pharyngeal slits open to fully functional gills supplied by four aortic arches (III–VI)

Question 15

Describe gills in African lungfish

Answer 15

o 1st pharyngeal slit reduced to a spiracle, associated aortic arch (I) also reduced

o In the African lungfish (Protopterus) functional gills reduced further:
▪ 3rd and 4th gills are absent entirely, their aortic arches (III–IV) (above)
▪ 5 & 6 present and functional as gills

Question 16

Describe gills in general in all lungfish

Answer 16

o 1st pharyngeal slit reduced to a spiracle, associated aortic arch (I) also reduced
o In all lungfishes, the efferent vessel of the most posterior aortic arch (VI) gives rise to the pulmonary artery but maintains its connection to the dorsal aorta via the short ductus arteriosus

Question 17

In tetrapods, what is the fate of the first, second, and fifth aortic arches?

Answer 17

all lost in adulthood in tetrapods

Question 18

How many external gills do most larval salamanders have? Which aortic arches are they derived from?

Answer 18

o First two aortic arches (I, II) disappear early in development

o Most larval salamanders:
▪ Next three aortic arches (III–V) carry external gills
▪ Arch VI sprouts the pulmonary artery to the developing lung
▪ External gills are lost following the larva’s transformation into the adult, but the aortic arches are retained as major systemic vessels

Question 19

Describe gills in adult salamander

Answer 19

▪ Section of ventral aorta between arches III and IV becomes the common carotid artery
▪ Arches IV, V constitute major systemic vessels that join the dorsal aorta
▪ Arch VI: joins the dorsal aorta - forming the ductus arteriosus and the pulmonary artery; Pulmonary loop, maintains D.A. connection

Question 20

What is the carotid duct?

Answer 20

o In larval amphibians (salamanders), lost in adult stages
o Carotid duct: Closes at metamorphosis; Forces the carotids to fill with blood from a derivative of the ventral aorta

Question 21

Ductus arteriosus

Answer 21

This is a fetal blood vessel that connects the pulmonary artery to the aorta, allowing blood to bypass the non-functioning fetal lungs and flow directly into the systemic circulation.

Question 22

Which vessels are derived from the ventral aorta in amniotes?

Answer 22

The ventral aorta in amniotes gives rise to the aortic arches, which form major arteries such as the carotid arteries, subclavian arteries, and parts of the aorta.

Question 23

Which systemic arch persists in birds? Mammals?

Answer 23

Aortic/systemic arches III, IV, and VI