Zoo 430: Exam 3

Front 1

In the first stage of heart development, what junction of veins thicken?

Back 1

The walls of the ventral aorta and (paired) vitelline veins

Front 2

At what intersection does the heart develop? What state is the blood in?

Back 2

The ventral aorta with the paired vitelline veins; blood is deoxygenated

Front 3

In the second stage of heart development, what occurs?

Back 3

Common cardinals appear at the intersection of the vitelline veins and ventral aorta; walls continue to thicken

Front 4

In the third stage of heart development, what occurs?

Back 4

Intersection of vessels become a linear system of chambers (from bottom to top: sinus venosus, atrium, ventricle, conus arteriosus)

Front 5

What is the direction of blood flow through the new linear system of chambers (stage 3 of heart development)?

Back 5

1. Sinus Venosus
2. Atrium
3. Ventricle
4. Conus Arteriosus

Front 6

What 4 inputs of blood come into the sinus venosus (stage 3 of heart development)?

Back 6

- Paired cardinals
- Paired vitellines

Front 7

Where does blood flow after the conus arteriosus?

Back 7

Ventral Aorta

Front 8

Which chamber receives O2 poor blood from the body and is the site of the heart beat initiation (in ancestral vertebrates)?

Back 8

Sinus Venosus

Front 9

Which chamber contracts to send blood to the ventricles?

Back 9

Atrium

Front 10

The atrium differs from the ventricle how?

Back 10

Atrium - thinner walls, contraction weak
Ventricle - thicker walls, contraction strong

Front 11

In stage 4 of heart development, what occurs?

Back 11

The linear sequence of chambers folds so that the ventricle (and conus arteriosus) is ventral (atrium and sinus venosus fold behind out of view).

Front 12

What is the atrium called in humans?

Back 12

Auricle

Front 13

In the development of the heart/circulatory system, what changed?

Back 13

- Single circut --> Double circuit
- All blood in heart O2 poor --> blood in heart partitioned into O2 rich and O2 poor

Front 14

Generally, how are chambers evolved to partition O2 rich and O2 poor blood?

Back 14

With partitions

Front 15

In the ancestral/embryonic condition, aortic arches are identified by what?

Back 15

Roman numerals (constant to see homology, even when some AAs are lost) I-VI.

Front 16

The ventral aorta extends cranially to become what?

Back 16

External Carotid

Front 17

The ancestral aortic arches procede dorsally to become what?

Back 17

Dorsal Aorta

Front 18

The internal carotids come from the (ventral/dorsal) side and flow into what structures?

Back 18

Dorsal --> Aortic Arches --> Dorsal Aorta

Front 19

In sharks, which of the aortic arches is lost? What does it become?

Back 19

Aortic Arch I --> Part of Carotids (external and internal)

Front 20

In sharks, what happens to aortic arches II-VI?

Back 20

Split into two vessels, afferent and efferent branchials

Front 21

What is the function of the afferent and efferent branchials in sharks?

Back 21

In capillary beds of gills for O2 pickup

Front 22

The afferent/efferent branchials are designated what (SHARKS)?

Back 22

1-5 (anterior to posterior)
(AA II = A/E 1)
(AA III = A/E 2)
(AA IV = A/E 3)
AA V = A/E 4)
AA VI = A/E 5)

Front 23

Carotids are not joined by what (in SHARKS)?

Back 23

Aortic Arches

Front 24

In teleosts, which aortic arches are lost? What do they become a part of?

Back 24

AA I and II lost - become part of carotids

Front 25

Are carotids more prominent in ancestral species or derived species?

Back 25

More derived, as aortic arches are lost to become part of carotids.

Front 26

In teleosts, how are the afferent and efferent branchials designated?

Back 26

1-4 (anterior to posterior)
(AA III = A/E 1)
AA IV = A/E 2)
AA V = A/E 3)
AA VI = A/E 4)

Front 27

Which species gave rise to tetrapods?

Back 27

Lungfish (of Sarcopterygia)

Front 28

What ecology gave rise to the air-breathing seen in lungfish?

Back 28

1) Stagnant / Ephemeral H2O with little dissolved O2
2) Or in ocean

Front 29

What circulation is seen in lungfish?

Back 29

- Gills - if O2 rich water
- Lungs - if not using gills

Front 30

From what did lungs evolve in lungfish?

Back 30

Outpocketing of endoderm (pharynx) that never breaches to outside

Front 31

In lungfish, what are 4 evolved features which help O2 flow?

Back 31

1) Atrium divided by interatrial septum
2) Ventricle divided by interventricular septum
3) Conus Arteriosus has spiral valve
4) Pulmonary vein returns O2-rich blood

Front 32

What kind of veins bring blood back to the heart (lungfish)?

Back 32

Systemic veins via the sinus venosus

Front 33

In lungfish, does the atrium or the ventricle have a complete partition?

Back 33

- Atrium (interatrial septum) - keeps blood separate
- Ventricle (interventricular septum) - scaffold - doesn't prevent blood mixing completely

Front 34

What is the purpose of the spiral valve seen in the conus arteriosus?

Back 34

Keeps O2 rich and O2 poor blood separated when blood enters conus arteriosus / ventral aorta and AA system

Front 35

Which vein returns oxygen rich blood to the left atrium?

Back 35

Pulmonary veins

Front 36

In lungfish, which of the aortic arches are used when the gills are active? Which are shut down?

Back 36

Active: AA II, V, VI
Shutdown: AA III, IV (and pulmonary artery and vein)

Front 37

Which of the ancestral aortic arches, in lungfish, become afferent and efferent branchials? Systemic arches?

Back 37

A/E Branchials: AA II, V, VI
Systemic Arches: AA III, IV

Front 38

In lungfish, which of the aortic arches are active when the lungs are active? Which are shut down?

Back 38

Active: AA III, IV, VI (pulmonary artery - to lungs), pulmonary vein
Shutdown: AA II, V

Front 39

Which of the ancestral aortic arches in lungfish is lost?

Back 39

AA I --> Part of carotids

Front 40

When lungfish are using their gills, what is the cycle?

Back 40

Single Circuit pattern w/ A/Es; systemic arches shut down

Front 41

What are the characteristics of the air breathing mechanism in lungfish?

Back 41

1) Gills shut down (A/E receive little blood)
2) O2 poor blood to AA VI - modified to pulmonary artery which takes blood to lungs
3) New pulmonary vein takes O2 rich blood back to heart
4) O2 rich blood sent to body via systemics and external carotids

Front 42

What do the 6 ancestral aortic arches correspond to in lungfish?

Back 42

I = lost
II = 1 A/E
III = systemic arch
IV = systemic arch
V = 2 A/E
VI = 3 A/E

Front 43

In lungfish, which vessel is introduced in the lung system?

Back 43

Pulmonary vein which takes oxygen rich blood from lungs to heart

Front 44

What are the three circuits in the lungfish?

Back 44

1) Pulmonary Circuit
2) Systemic Circuit
3) Gill Circuit

Front 45

What vessels are involved in the pulmonary circuit?

Back 45

- Pulmonary Artery - going TO the lungs
- Pulmonary Vein - going FROM the lungs (*new)

Front 46

Which ancestral aortic arch is shared in lungfish between the gills and lungs?

Back 46

AA VI

Front 47

What makes up the systemic circuit of lungfish?

Back 47

- Vessels that do not form A/E
- Modified from AA III and IV

Front 48

What is the function of the systemic circuit in lungfish?

Back 48

To distribute O2 rich blood to the body

Front 49

What makes up the gill circuit of lungfish?

Back 49

- Vessels that form A/E
- AA II, V, VI
*AA VI facultative switch between lung and gill circuit*

Front 50

In lungfish, which vessels takes O2 poor blood to the mouth?

Back 50

External carotids

Front 51

In lungfish, which vessels take O2 rich blood to the head?

Back 51

Internal Carotids

Front 52

Where do external carotids pick up blood on their way where?

Back 52

Pick up blood in mouth via mouth lining; now O2 rich blood returns to body

Front 53

Why is it important that internal carotids always carry O2 rich blood?

Back 53

They are headed to the head!

Front 54

What is unusual about the circulatory patterns of amphibians?

Back 54

Living amphibians are oddballs because they are highly evolved from Labyrinthodonts, therefore there is no clear pattern.

Front 55

In adult amphibians, which aortic arches are lost?

Back 55

AA I-II, and V (always in frogs, sometimes in salamanders)

Front 56

Which aortic arches remain in adult amphibians? How do they differ between salamanders and frogs?

Back 56

AA III, IV, VI remain
(in salamanders - all A/E branchials)
(in frogs - no A/E branchials)

Front 57

In salamanders, what links the pulmonary and gill circuits?

Back 57

Aortic Arch VI

Front 58

Do salamanders have systemic arches?

Back 58

No, the remaining aortic arches are all afferent/efferent branchials.

Front 59

What are the multiple sources of O2 uptake in salamanders?

Back 59

- Gills
- Lungs
- Skin

Front 60

How do salamanders obtain O2 through their skin?

Back 60

Skin is membranous and can absorb O2 since they are bathed in O2 rich waters

Front 61

Why is the inefficient separation of O2 rich and O2 poor blood not fatal in salamanders?

Back 61

They are water-living, and typically live in O2 rich waters (constant uptake up O2)

Front 62

The remaining aortic arches (III, IV, VI) of frogs define what three pathways?

Back 62

- Carotid Complex
- Systemic Circuit
- Pulmonary Circuit

Front 63

How is blood flow isolated to the carotids in frogs?

Back 63

- Ductus Caroticus (portion of dorsal aorta between AA III and IV) is lost

Front 64

How is blood flow isolated to the body in frogs?

Back 64

- AA IV and dorsal aorta send blood from the Common Carotid to the body

Front 65

What happens to the ancestral ventral aorta in frogs?

Back 65

The portion between AA III and IV forms the common carotid

Front 66

How is blood flow isolated to the lungs in frogs?

Back 66

- Ductus Arteriosus (distal portion of AA VI) is lost; prevents it from connecting to the dorsal aorta

Front 67

The Ductus Caroticus and Ductus Arteriosus are lost in which species?

Back 67

Frogs (not in salamanders)

Front 68

Frogs have what two circuits and complex?

Back 68

- Carotid Complex
- Systemic Circuit
- Pulmonary Circuit

Front 69

What makes up the carotid complex of frogs?

Back 69

- AA III
- External and Internal Carotids
- Ventral Aorta anterior to AA IV (= Common Carotid)

Front 70

What makes up the systemic circuit of frogs?

Back 70

- AA IV
- Paired Dorsal Aortas

Front 71

What makes up the pulmonary circuit of frogs?

Back 71

- Proximal AA VI (distal part is lost - ductus arteriosus)
- Pulmonary Artery (homolog of AA VI)
- Pulmonary Vein (new vein)

Front 72

What are some innovations of the amphibian heart?

Back 72

- Shortened ventral aorta
- Bulbous Arteriosus (reduces tendency of O2 rich and low blood mixing in Ventral Aorta)
- Left ventricle contracts more strongly than RV
- Ventricular Trabeculae (reduces mixing between ventricles)

Front 73

What are some mechanisms which reduce the mixing of O2 rich and O2 low blood in the amphibian heart?

Back 73

- Shortened ventral aorta (drops blood pressure to prevent mixing)
- Bulbous arteriosus (bulging of ventral aorta which reduces the tendency of mixing)
- Ventricular trabeculae (mini walls coming out of floors of ventricles which reduces lateral mixing)

Front 74

From what does blood enter the right atrium?

Back 74

O2 poor blood from body enters sinus vinosus which goes into the right atrium

Front 75

From what does blood enter the left atrium?

Back 75

O2 rich blood from lungs (pulmonary veins) enters left atrium

Front 76

What is the bulging expansion of the ventral aorta called which is new in frogs?

Back 76

Bulbous arteriosus

Front 77

Why does the left ventricle contract more strongly than the right ventricle?

Back 77

Helps get the oxygenated blood up to the carotid complex and systemic arch

Front 78

Where does the blood from the right atrium go? Is it O2 rich or poor?

Back 78

O2 poor blood goes to the pulmonary artery

Front 79

What paired openings leave the ventral aorta (anterior to posterior)? From what ancestral aortic arches do they evolve?

Back 79

- Carotid Complex - AA III
- Systemic Arch - AA IV
- Pulmonary Artery - AA VI

Front 80

What are 5 characteristics of adult reptilian circulation?

Back 80

1) No gills
2) No ductus caroticus / arteriosus (independent carotid system and lungs)
3) Three blood pathways (carotid complex, systemic circuit, pulmonary circuit)
4) Heart may or may not have complete interventricular septum (complete in crocs)
5) Sinus Vinosus receives O2 poor blood

Front 81

What is the first species to have a complete interventricular septum?

Back 81

Crocodiles

Front 82

The carotid complex of crocodiles emanates from what structure?

Back 82

The ventral aorta on the left side of the heart (AA III)

Front 83

What happens to the ancestral aortic arch IV in crocodiles?

Back 83

Two distinct structures: left aorta and right aorta

Front 84

Which side of the heart is the Left Aorta from?

Back 84

From right side of heart; going to LEFT side

Front 85

Which side of the heart is the Right Aorta from?

Back 85

From left side of heart; going to RIGHT side

Front 86

From what side of the heart do the pulmonary arteries leave?

Back 86

Right side of heart

Front 87

What three main vessels exit the heart of a crocodile?

Back 87

- Pulmonary Arteries
- Left Aorta
- Right Aorta (to which the carotid complex branches off of)

Front 88

What chamber is lost in the crocodile heart? Which three remain?

Back 88

- No conus arteriosus / spiral valve
- Sinus venosus, atria, ventricles are still present

Front 89

When the oxygen rich blood leaves the left ventricle, what is its path?

Back 89

- Through semilunar valve
- Into Right Aorta (despite being on left side)
- May cross through Foramen of Panizza (to go to left aorta)
- Ascends up right aorta and may branch off to carotid complex

Front 90

What is the hole that connects the left and right systemic aortas in crocodiles?

Back 90

Foramen of Panizza

Front 91

The crocodile has two significant pathways for blood depending on whether it is breathing air or submerged, what are the differences?

Back 91

- Air-Breathing - returns O2 rich blood from lungs; higher pressure in LV; blood passes through foramen of panizza so O2 rich blood goes to left and right aortas
- Submerged - returns NO O2 rich blood from lungs; higher pressure in RV; O2 poor blood passes through foramen and mixes with O2 rich blood in R aorta; L aorta has only O2 poor blood

Front 92

In comparing amniotes (reptiles, birds, mammals) what happens to the sinus venosus?

Back 92

- Reptiles - SV complete and separate chamber
- Birds - SV reduced in size
- Mammals - SV gone

Front 93

In comparing amniotes (reptiles, birds, mammals) where is the placement of the Sino-Atrial node?

Back 93

- Reptiles - On Sinus Venosus
- Birds - Resides in R. Atrium
- Mammals - Resides in R. Atrium

Front 94

In comparing amniotes (reptiles, birds, mammals), which of right and left aortas is present?

Back 94

- Reptiles - both are present
- Birds - single R Aorta
- Mammals - single L Aorta

Front 95

In comparing amniotes (reptiles, birds, mammals), where does the carotid complex branch off of

Back 95

- Reptiles - off of R Aorta
- Birds - off of R Aorta
- Mammals - off of L Aorta

Front 96

Birds, Mammals, and some Reptiles (crocodiles) always have a what structure which is not complete in those ancestral to them?

Back 96

Interventricular septum

Front 97

What happens to the original, ancestral four chambers of the heart (in amniotes)?

Back 97

- Lose Sinus Venosus
- Retain Atrium (splits in two)
- Retain Ventricle (splits in two)
- Lose Conus Arteriosus

Front 98

In mammals, the L aorta is maintained, which side of the heart does this come off of?

Back 98

Left (O2 rich) side

Front 99

Which vessel sends O2 rich blood to the arms?

Back 99

Subclavians

Front 100

The base of the right subclavian in adult mammals in a remnant of which aortic arch?

Back 100

Right IV AA

Front 101

What does the term brachiocephalic refer to?

Back 101

Subclavian (specifically the right one) being attached to a shared vessel (brachiocephalic artery, BA) with the common carotid

Front 102

Are mammals typically brachiocephalic or non brachiocephalic? What are the exceptions?

Back 102

- Not Brachiocephalic (subclavians not connected to common carotid)
- Internal and External carotid pairs both extend off of single common carotid
- Exceptions: Cats and Humans

Front 103

What makes cats brachiocephalic pattern unique from the typical nonbrachiocephalic pattern of most mammals?

Back 103

Brachiocephalic, right subclavian is attached to common carotid, forms the brachiocephalic artery (BA) which branches to the CC and RS

Front 104

What makes humans brachiocephalic pattern unique from the typical nonbrachiocephalic pattern of most mammals?

Back 104

Not typical common carotid (internal and external carotid pairs ares split, no longer attached to same vessel); right subclavian is attached to I and E common carotid on right side, forming a new brachiocephalic artery

Front 105

What is the predicted "brachiocephalic" condition for carotid draining patterns?

Back 105

- Internal and External carotids pairs will be separated to have two attachments (each w/ I and E)
- Right and Left subclavians will attach to Left aorta separately (therefore NOT brachiocephalic)
- This would maximize blood flow to head

Front 106

What may be a reason why the predicted condition of carotid / subclavian drainage pattern has not come about?

Back 106

This maximized flow of blood to the head would cause bigger brains; however it is necessary that brains only reach a certain size for giving birth

Front 107

Which set of veins form a large H shape centering at the heart (in the ancestral/embryonic model)?

Back 107

Cardinals (common, anterior, posterior)

Front 108

Which vein is unpaired and carries blood to the left vitelline (in the ancestral/embryonic model)?

Back 108

Subintestinal vein

Front 109

Which paired veins flow into the subclavian and drain the hindlimbs via the iliac?

Back 109

Lateral abdominals

Front 110

How do sharks venous system change compared to the ancestral/embryonic model?

Back 110

- Renal Portal formed from posterior cardinal
- Hepatic Portal formed from subintestinal
- Systemic Hepatics form from vitellines
-

Front 111

Specifically, what happens to the posterior cardinal in evolving to the SHARK?

Back 111

- Loss of piece of posterior cardinal above the kidney
- Splits veins into two pieces (portion still connected to the common cardinal = Posterior Cardinal; portion attached to kidneys which joins posteriorly = Renal Portal)

Front 112

What does the formation of the renal portal do to blood flow of the shark?

Back 112

Blood in posterior cardinal must flow through kidney before returning to heart
(*this change does not persist throughout evolution*)

Front 113

What happens to the subintestinal vein of the ancestral/embryonic model as it evolves to the shark and future species?

Back 113

- Subintestinal vein invests in liver once formed; terminates here (as opposed to a vitelline vein)

Front 114

What happens to the vitellines of the ancestral/embryonic model as it evolves to the shark and future species?

Back 114

Vitellines become sinusoids in liver (channels for blood in soft organs) => Systemic Hepatics

Front 115

In the ancestral condition, what was the path of blood through the kidneys?

Back 115

- Renal artery dumps O2 rich blood in kidney
- Posterior cardinal picks up O2 poor blood from kidney
*One rinse cycle for blood*

Front 116

In the derived condition, what is the path of blood through the kidneys?

Back 116

- Renal artery dumps O2 rich blood in kidney
- Posterior cardinal picks up O2 poor blood from kidney
- Renal portal dumps O2 poor blood in kidney
*Two rinse cycles for blood*

Front 117

Which features which evolve in sharks are conserved on through mammals?

Back 117

- Hepatic portals
- Systemic hepatics

Front 118

Which three venous structures are reduced or eliminated in tetrapods (become part of vena cava)?

Back 118

- Cardinals
- Renal Portals
- Lateral Abdominals

Front 119

What new venous structure is derived in tetrapods?

Back 119

Posterior Vena Cava (postcava)

Front 120

Which major vessel is the new path for blood to return to heart from the posterior portion of the body?

Back 120

Posterior Vena Cava

Front 121

In embryonic tetrapods, which structure that is eliminated in adults, continues to function embryonically?

Back 121

Old lateral abdominals

Front 122

What derived features are seen in the venous circulation of larval frogs and adult salamanders?

Back 122

- Lateral Abdominals --> Ventral Abdominal (unpaired, portal to liver)
- Posterior Vena Cava (derived from posterior cardinals and systemic hepatics; flows directly to sinus venosus)

Front 123

Where does the posterior vena cava flow to (salamanders, frogs, reptiles and birds)?

Back 123

Sinus Venosus of heart

Front 124

What is the function of the posterior vena cava?

Back 124

Allows blood in posterior body to return more directly back to the heart

Front 125

Sharks evolve a renal portal to pass blood through the kidneys, in which species does this evolution revert back to the single systemic renal vein which flows into the postcardinal (i.e., not portal)?

Back 125

Adult Salamanders and Larval Frogs

Front 126

In adult frogs, what are the newly derived features?

Back 126

- No posterior cardinals (causes formation of Renal Portal, as seen in shark)
- Ventral abdominals (unpaired, portal into liver, same as in larval frog/adult salamander)
- Posterior vena cava (vessel returning caudal blood to heart)

Front 127

What three inputs go into the heart of the adult frog?

Back 127

- Post cava
- Right common cardinal
- Left common cardinal

Front 128

The anterior cardinals of ancestral vertebrates are homologous to what structure?

Back 128

Jugulars

Front 129

The common cardinals of ancestral vertebrates are homologous to what structure?

Back 129

Precavas

Front 130

In adult reptiles and birds, which ancestral features of the venous circulation are maintained?

Back 130

- Renal Portal (incomplete)
- Lateral Abdominals (again paired as in sharks!)

Front 131

In adult reptiles and birds, which features of the venous circulation are derived?

Back 131

- Renal Portal (some vessels bypass kidney)
- Lateral Abdominals (portal in liver, instead of to subclavian)
- Sinus Venosus receives all caudal blood via postcava

Front 132

In adult reptiles and birds venous circulation, what ways can caudal blood return to the heart?

Back 132

- Via renal portal (to postcava)
- Via posterior vena cava bypass of kidney
- Via lateral abdominals which are portal in liver (to postcava)

Front 133

In the venous circulation of adult mammals, which ancestral paired anterior veins remain?

Back 133

- Precavas (unpaired in some)
- Jugulars
- Subclavians

Front 134

In the venous circulation of adult mammals, what are the derived features?

Back 134

- No sinus venosus (blood returns to right atrium from body via...)
- Postcava directly empties into right atrium
- Posterior cardinals reduced (L=hemiazygous; R=azygous) and drain rib cage into postcava
- No renal portal
- No abdominal stream

Front 135

When evolutionarily does the sinus venosus disappear? Where does blood get dumped then?

Back 135

Adult mammals
- Blood gets dumped from postcava into the right atrium

Front 136

When do the hemiazygos(L) and azygos(R) appear? What are they homologous to? What is their function?

Back 136

Appear in adult mammals; reduced posterior cardinals; drain rib cage into postcava

Front 137

In venous circulation of adult mammals, what is the only route for systemic blood to return to the heart? What is incorporated into this vein?

Back 137

Posterior Vena Cava
- Posterior Cardinals (azygos, hemiazygos)
- Systemic Hepatics
- Renal Portal (absent except for this portion)

Front 138

Mammals (except for cats and humans) have how many routes for venous blood TO the heart? What are they?

Back 138

3: Right precava, Left precava, Postcava

Front 139

How many routes for venous blood TO the heart do cats and humans have? What are they?

Back 139

2: Right precava and Postcava

Front 140

What features are lost in human and cat venous systems?

Back 140

- Hemiazygos
- Left Precava (partially-coronary sinus)

Front 141

In humans and cats venous systems, what is added?

Back 141

- Brachiocephalic Vein (brings anterior blood from left side (jugular and subclavian) to the right precava to enter right atrium)
- Coronary Sinus (pouch on surface of heart; homolog of L precava)

Front 142

What is the function of the coronary sinus?

Back 142

- Pouch on surface of heart which is homologous to the left precava
- Drains myocardium and returns it to right atrium

Front 143

Embryos of mammals have what venous drainage patterns?

Back 143

- Cardinals (anterior/common/posterior)
- Many crossover vessels (R-L) between corresponding cardinals
- Retention of one cross-branch produces brachiocephalic shunt

Front 144

In reptile and bird embryos, there are two significant paired veins; what are they?

Back 144

- Lateral Abdominals (drain hindlimbs, O2 poor, empty into heart, SV)
- Allantoic Vein (brings O2 rich blood from allantois, drains into abdominal stream)

Front 145

What is the concentration of O2 in blood in reptile and bird embryos as it is returned to the heart (SV)?

Back 145

Diluted O2 blood delivered to heart (O2 poor blood from hindlimbs dilutes the O2 rich blood from allantoic vein in the lateral abdominals)

Front 146

What is the imperfection of the reptile and bird embryo system?

Back 146

Fully oxygenated blood from allantois never distributed at O2 rich concentration b/c diluted by blood from lateral abdominals

Front 147

What happens to the lateral abdominals in adult reptiles?

Back 147

Portal into liver; drains hindlimbs only (O2 poor blood); doesn't mix with allantoic vein since not embryo

Front 148

In adult reptiles, what takes oxygen poor blood from the liver to the heart (SV)?

Back 148

Posterior vena cava

Front 149

What happens to the lateral abdominals in adult birds?

Back 149

Turns into inferior mesenteric ligaments; do not carry blood

Front 150

In adult birds, what is the homolog to the lateral abdominals?

Back 150

Inferior Mesenteric Ligaments

Front 151

In embryonic mammals, what is the umbilical vein derived from?

Back 151

Ancestral abdominal stream and allantoic vein

Front 152

What is the function of the umbilical vein?

Back 152

Picks up O2 rich blood in placenta and takes to Sinus Venosus of heart

Front 153

In embryonic mammals, where is the O2 rich blood from the umbilical vein diluted?

Back 153

At liver by the posterior vena cava which is draining O2 poor blood

Front 154

What houses the umbilical vein?

Back 154

Umbilical Chord

Front 155

What three things is the placenta composed of?

Back 155

- Maternal Tissues (mother)
- Allantois (embryo)
- Chorion (embryo)

Front 156

What is the function of the placenta?

Back 156

Exchange of O2 and metabolites between mother and embryo

Front 157

What is the portion of the umbilical vein which is found in the liver?

Back 157

Ductus Venosus

Front 158

What happens to the ductus venosus and umbilical vein in adults?

Back 158

DV => Ligamentum Venosus
UV => Ligamentum Teres (round ligament)

Front 159

What is the abdominal stream in embryonic mammals? In adult mammals?

Back 159

Umbilical Vein in embryo
No abdominal stream in adults

Front 160

The abdominal stream of the mammal fetus does what?

Back 160

Carries O2 rich blood in embryo; associated with vessel draining extra-embryonic membrane

Front 161

What happens to the adult aortic arches in mammals?

Back 161

Reduction of embryonic arches

Front 162

What is the embryonic environment of mammals?

Back 162

Amnion fluid-filled cavity
Lungs shut down

Front 163

What is the route of blood through fetal structures of mammals, beginning at the placenta up until the right atrium?

Back 163

- O2 rich blood passes through umbilical vein to liver
- Diluted with O2 poor blood from Hepatic Portal Vein (some) and Postcava (all) @Ductus Venosus
- 1x diluted blood flows up postcava to Right Atrium

Front 164

What is the route of blood through fetal structures of mammals, beginning at the right atrium (coming from postcava) until it leaves through the ascending branch of the left aorta?

Back 164

- 1x diluted blood flows into right atrium past flap (remnant of sinus venosus) which regulates flow
- Blood shoots across right atrium through Foramen Ovalae into left atrium
- Enters Left ventricle
- Leaves through ascending branch of L aorta

Front 165

What is the route of blood through fetal structures of mammals, beginning at the right atrium (enters from anterior venacava) until it gets to the Ductus Arteriosus?

Back 165

- O2 poor blood enters right atrium from anterior vena cava
- Flows into right ventricle
- Enters Pulmonary Trunk (which would usually go to lungs, but they are closed)
- Flows past lungs to Ductus Arteriosus (distal AA VI)

Front 166

What is the route of blood through fetal structures of mammals, as blood leaves the ascending branch of the left aorta back through to the placenta?

Back 166

- 1x diluted blood can go anteriorly to the carotid complex/left carotid
- Diluted second time by O2 poor blood in ductus arteriosus
- Enters aorta where blood can be sent to arteries of body
- Blood enters umbilical artery on way back to the placenta (returns 2x diluted)

Front 167

What is the hole between the two atriums of the fetal circulation in mammals? What is its significance?

Back 167

- Foramen Ovalae - 1x diluted blood from postcava shoots through here to get to left atrium

Front 168

Where is the ductus venosus found?

Back 168

Between the Hepatic Portal Vein and the Postcava (from umbilical vein)

Front 169

Where is the Ductus Arteriosus found?

Back 169

Portion of pulmonary trunk past the lungs which connects to the descending branch of the aorta

Front 170

How diluted is the blood which is sent to the carotid complex in embryonic mammals?

Back 170

1x diluted (with blood from precava); best possible is sent here, although this dilution probably limits brain growth (birthing...)

Front 171

What changes happen to the mammal fetus once it takes its first breath?

Back 171

- Nerve impulse triggered to cause ductus arteriosus to shrivel into ligament
- Foramen Ovale closes to form wall (fossa ovalae)
- Umbilical artery and vein = chord, severed from outside (artery becomes ligament between naval and bladder)
- Ductus venosus shrivels into ligament

Front 172

What happens to the ductus arteriosus and ductus venosus at the moment fetuses take their first breath?

Back 172

Both shrivel up into Arterial ligament and Ligamentum Venosus respectively.

Front 173

What happens if the Foramen Ovalae doesn't completely close up at the first breath of the baby mammal?

Back 173

Heart Murmur

Front 174

Which ligament can be felt between the naval and the bladder?

Back 174

Ligament from the umbilical artery shriveling up at first breath

Front 175

What are the three basic features of the nervous system?

Back 175

1. Stimulus @ Receptor - sense organ
2. Impulse @ Conductor - neuron
3. Response @ Effector - muscle or gland

Front 176

Prior to the neuron, what ancestral structures could have existed?

Back 176

- Neuromuscular cell - one structure; combines all three components of N.S. (receptor, conductor, effector) - hypothetical
- Neurosensory Cell - one structure; combines two components of N.S. (receptor and conductor) - found in nasal epithelium

Front 177

What are the two functional types of neurons found in vertebrates?

Back 177

- Sensory Neurons
- Motor Neurons

Front 178

What is the structure of a sensory neuron?

Back 178

- Dendrite to cell body (receptor)
- Cell Body (outside of CNS in sensory neuron)
- Axon from cell body to inside CNS

Front 179

What is the structure of a motor neuron?

Back 179

- Cell body located in CNS
- Axon extends out of CNS to effector (muscle or gland)

Front 180

What is the structure of association neurons?

Back 180

Entire neuron located inside of CNS; including cell body

Front 181

What is the function of association neurons?

Back 181

- Carry impulse up (ascending) or down (descending) CNS
- Carry impulse across (L-R) CNS (decussation)
- Complete simple reflex pathway outside brain (in spinal cord)

Front 182

What do "Decussating Fibers" do? Where are they found?

Back 182

Found in Association Neurons - carry impulses across from one side of the body to the other so body knows what is happening

Front 183

Which type of neurons can have multiple dendrites and axons?

Back 183

Motor and Association Neurons

Front 184

Which type of neurons have only a single dendrite and axon per cell body?

Back 184

Sensory Neurons

Front 185

How can the impulse of neurons be sped up?

Back 185

Myelin sheath blocks form donuts around the axon allowing the impulse to jump between

Front 186

What color do axon cylinders look? What color does myelin look?

Back 186

Axon Cylinder - grey
Myelin - white

Front 187

What cells are associated with Myelin production?

Back 187

- Glial Cells - inside CNS
- Schwann Cells - outside CNS

Front 188

What is myelin made out of?

Back 188

Fatty white looking cells