Lecture 12: Circulation

Question 1

What are vertebrate characteristics of the circulatory system?

Answer 1

• Blood cells contain hemoglobin
• Closed circulatory system
• Heart is compartmentalized into chambers
• Aorta positioned in front of spinal column, behind viscera

Question 2

What are the tetrapod characteristics of the circulatory system?

Answer 2

• reduced number of aortic arches

- Pulmonary circulation (gills or lungs oxygenate blood)

Question 3

What are the mammalian characteristics of the circulatory system?

Answer 3

• Pulmonary and systemic circuit chambers in heart completely isolated from each other
• Aortic arch on left
• Involvement in regulation of body temperature (homeotherms)

Question 4

What is the one main characteristic specific to humans of the circulatory system?

Answer 4

-Increased efficiency in keeping brain cool

Question 5

What is hemolymph, what type of organisms have this, ad what does it occupy?

Answer 5

Circulatory fluid of invertebrates, occupies homecoels

**different from hemoglobin because it uses hemocyanin and copper

Question 6

What is an open circulatory system?

Answer 6

Blood is pumped into body cavities (hemocoels) where tissues are surrounded by blood (hemolymph)

Question 7

What does the color of blood depend on?

Answer 7

The protein that is used to transport oxygen

Question 8

How many chambers of the heart do fish have?

Answer 8

1 ventricle 1 atria

Question 9

How many chambers of the heart do amphibians have?

Answer 9

2 atria, 1 ventricle

Question 10

How many chambers of the heart do reptiles have?

Answer 10

2 atria 2 ventricle

Question 11

How many chambers of the heart do mammals and birds have?

Answer 11

2 atria and 2 ventricles

Question 12

The sequence of the ________ ________- ________-_________-__________ _______ in the primitive heart is mirrored in living fishes an din the early-stage human embryonic heart

Answer 12

Sinus venosus-atrium-ventricle-conus arteriosus

Question 13

What is the sinus venosus?

Answer 13

Confluence of major veins (bringing blood to heart)

Question 14

What is the conus arteriosus?

Answer 14

Strongest contraction; pumps blood out to vessels

Question 15

There transition from the primitive four chambered heart to the modern mammalian is an excellent example of how evolution can work within what?

Answer 15

The framework of ontogenetic sequences to changes a developmental process by extending it in a new direction

Question 16

What is “ontogeny recapitulating phylogeny”?

Answer 16

During their development, organisms repeat evolutionary stages of ancestral species

**this doesnt actually occur

Question 17

The observation that many even distantly related species resemble each other at early developmental stages reflects how changes in developmental timing (__________), and/or the retention of juvenile characteristics in some species (________) are ways in which evolution works within already existing complex systems.

Answer 17

Heterochrony

Neoteny

Question 18

How doe the atrioventricular valves function?

Answer 18

OPEN:
1. Blood returning to the heart fills atria, putting pressure against AV valves; forced open
2. As ventricles fill, AV valve flaps hang limply into ventricles
3. Atria contract, forcing additional blood into ventricles
CLOSE:
1. Ventricles contract forcing blood against AV valve cusps
2. AV valves close
3. Papillary muscles contract and chordae tendineae tighten, preventing valve flaps from everting into atria

Question 19

How do the Aortic and semi-lunar valves function?

Answer 19

1. As ventricle contract and intraventricular pressure rises, blood is pushes up against semilunar valves, forcing them open.
2. As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close

Question 20

Which arteries make up the branches of left coronary artery and what is another name for these?

Answer 20

• Circumflex artery
• Anterior interventricular artery

**A.k.a. Left anterior descending (LAD)

Question 21

Where do the coronary arteries come off of?

Answer 21

The ascending aorta

Question 22

What does the pulmonary circuit consist of?

Answer 22

The chambers on the right side of the heart (R Atrium and ventricle) as well as the pulmonary arteries and veins

Question 23

What does the systemic circuit consist of?

Answer 23

Chambers on the left side of the heart (L atrium and ventricle), along with all the other named blood vessels

Question 24

Blood pumped out of the R ventricle is pumped into what?

Answer 24

Pulmonary artery to the lungs

Question 25

The pulmonary trunk bifurcates into what two things?

Answer 25

L pulmonary artery and R pulmonary artery

Question 26

What are the 2 branches of the R coronary artery?

Answer 26

Posterior interventricular artery | R marginal artery

Question 27

Mammalian fetal circulation reflects the reliance of the developing fetus on what?

Answer 27

Maternal blood supply

Question 28

Are fetal lungs functional? How do they develop?

Answer 28

Not functional, no pulmonary circuit yet but enough blood to allow lungs to develop

Question 29

Where does oxygenated blood from the placenta pass through in the fetus?

Answer 29

From placenta through liver, enter the IVC, flows into the R atrium of heart

Question 30

Are the atria fully separated in the fetus?

Answer 30

No, some blood form the IVC flows through the foramen oval into the R atrium

Question 31

Where does blood from the SVC in the fetus flow into? Why?

Answer 31

The R ventricle this functions to reduce volume and pressure of blood pumped into the R ventricle

Question 32

What allows more blood to be diverted away from the lungs and into the aorta and out to the fetal body?

Answer 32

Ductus arteriosus between the aorta and the pulmonary trunk

Question 33

In the fetus, where is the most highly oxygenated blood diverted to?

Answer 33

The developing heart tissue and itself and the brain

Question 34

The ductus arteriosus becomes what in the newborn?

Answer 34

Ligamentum arteriosum

Question 35

The foramen ovale in the fetus becomes what in the newborn?

Answer 35

Fossa ovalis

Question 36

The ductus venosus in the fetus becomes what in the newborn?

Answer 36

Ligamentum venosum

Question 37

The umbilical vein in the fetus becomes what in the newborn?

Answer 37

Ligamentum teres

Question 38

The umbilical arteries in the fetus becomes what in the newborn?

Answer 38

Medial umbilical ligaments

Question 39

What happens tot he vessel of the umbilical cord at birth?

Answer 39

The vessels empty and collapse

Question 40

What happens to the lungs at birth?

Answer 40

Empty of fluid and resistance to blood flow drops

Question 41

The constricting of what in the fetus allows blood to flow into the pulmonary arteries at birth?

Answer 41

Ductus arteriosus

Question 42

The overlapping flaps of the soon-to-be ______ ________ to close off the foramen ovale.

Answer 42

Interatrial septum

Question 43

What 2 things drain into the brachiocephalic veins that become the superior vena cava?

Answer 43

Right and left internal jugular veins

Question 44

Where does the blood supply to the head and neck originate form? Right and left side?

Answer 44

Aortic arch Right side=brachiocephalic trunk (R. Common carotid and R subclavian) Left side=L common carotid and L subclavian

Question 45

What sits to the R of the ascending aorta?

Answer 45

SVC, right auricle

Question 46

What sits to the L of the ascending aorta?

Answer 46

Pulmonary trunk

Question 47

What is the arterial supply to the brain?

Answer 47

Vertebral arteries | internal carotid arteries

Question 48

What is the arterial supply to the head?

Answer 48

External carotid arteries

Question 49

What is the arterial supply to the neck?

Answer 49

``` External carotid arteries Thyrocervical trunks (from subclavian) ```

Question 50

What drains the brain?

Answer 50

Rural sinuses to the internal jugular veins

Question 51

What drains the head?

Answer 51

Internal jugular veins External jugular veins Vertebral veins

Question 52

What drains the neck?

Answer 52

Internal jugular veins | External jugular veins

Question 53

What are the dural sinuses of the brain?

Answer 53

- Straight sinus - Occipital sinus - Marginal sinuses - Transverse sinus - Sigmoid sinus - Superior sagittal sinus* - Inferior sagittal sinus - Cavernous sinus - Superior petrosal sinus* - Inferior petrosal sinus*

Question 54

-What is the cerebral arterial circle or circle of Willis important for?

Answer 54

An important anastomosis of arteries around the sella turcica (sphenoid bone)

Question 55

What is the circle of Willis (cerebral arterial circle) formed from?

Answer 55

- Posterior cerebral arteries - Posterior communicating arteries - Internal carotid arteries - anterior cerebral arteries - Anterior communicating arteries

Question 56

What is the actual function of the circle of Willis?

Answer 56

It equalizes blood pressure in the brain and can provide collateral channels should one vessel become blocked

Question 57

How does the external carotid artery vary between macaque and humans?

Answer 57

Similar branching pattern to that of humans except for origin of maxillary artery

Question 58

Is the internal carotid artery similar in macaque and humans?

Answer 58

Yes

Question 59

How does the circle of Willis in macaque compare to those of humans?

Answer 59

It lacks an anterior communicating artery but instead the anterior cerebral artery unite to form one artery

Question 60

What vessel supplies the coronary arteries?

Answer 60

Ascending aorta

Question 61

What are the 2 parts of the descending aorta?

Answer 61

Thoracic part and abdominal part

Question 62

What are the 4 main groups of arteries found in the thoracic portion of the descending aorta?

Answer 62

- Intercostal arteries - Bronchial arteries - Mediastinal arteries - Esophageal arteries

Question 63

What does the azygos veins receive blood from?

Answer 63

- R intercostal veins - Hemi-azygos v. - R. ascending lumbar v. - Bronchial veins - most esophageal vv. - Most mediastinal vv.

Question 64

What does the azygos v. Itself drains into?

Answer 64

Superior vena cava

Question 65

What do the hemi-azygos and accessory hemi-azygos veins receive blood from?

Answer 65

- L. Intercostal veins - L. Ascending lumbar v. - Bronchial veins - Some lower esophageal vv.

Question 66

What is the internal vertebral venous plexus? What is its function?

Answer 66

It is a network of veins within the vertebral canal, surrounding the spinal cord and its coverings. It functions to return blood from the spinal cord and meninges. This plexus drains into the azygos system and then into the superior vena cava (SVC).

Question 67

What was determined to be the main intermediary between the SVC and internal vertebral venous system?

Answer 67

The azygos system

Question 68

Is there a functionally important connection between the lower azygos and hemi-azygos veins to the inferior vena cava?

Answer 68

No and the Bowsher article confirmed this

Question 69

The azygos system also functions in mediating the ______ pressure

Answer 69

CSF

Question 70

What branch of the abdominal aorta goes to the diaphragm?

Answer 70

Inferior phrenic

Question 71

Which branches of the abdominal aorta go to the GI tract?

Answer 71

Celiac, superior and inferior mesenteric

Question 72

What branches of the abdominal aorta go to the other organs not part of the gut tract?

Answer 72

Suprarenal, renal, gonadal (ovarian and testicular)

Question 73

Which branches of the abdominal aorta go to the body wall?

Answer 73

Lumbar arteries, these are analgous to intercostal arteries

Question 74

Where is the sympathetic chain in relation to the abdominal aorta?

Answer 74

Left lateral

Question 75

Where is the pancreas , splenic vein, left renal vein, 3rd part of duodenum, mesentary, nodes, autonomic plexus, lesser sac, stomach, omentum and small bowel in relation to the abdominal aorta?

Answer 75

Anterior

Question 76

Where it Y12-L4 and the left lumbar veins in relation to the abdominal aorta?

Answer 76

Posterior

Question 77

What is the hepatic portal system?

Answer 77

A venous network that drains the GI tract and shunts the blood to the liver for processing and absorption of transported materials

Question 78

What does blood exit the liver through? What do these merge with?

Answer 78

Hepatic veins that merge with the inferior vena cava

Question 79

Why is the hepatic portal system needed?

Answer 79

Because the GI tract absorbs digested nutrients and these nutrients must be processed and/or stored in the liver

Question 80

What are the 3 main things that make up the hepatic portal system?

Answer 80

Splenic vein Superior mesenteric vein Inferior mesenteric vein

Question 81

What artery supplies the midgut?

Answer 81

Superior mesenteric

Question 82

What artery supplies the foregut?

Answer 82

Celiac trunk

Question 83

What are the 3 arterial branches of the celiac trunk?

Answer 83

Left gastric a. Splenic a. Common hepatic a.

Question 84

What artery supplies the hindgut?

Answer 84

Inferior mesenteric