Cardiovascular Part III: Blood Vessels

Question 1

What are the three types of blood vessels?

Answer 1

Arteries - blood away from heart

Veins - blood towards heart

Capillaries - smallest, site of exchange btwn blood and tissue

Question 2

What are the three layers of a blood vessel? And the central space filled with blood?

Answer 2

Known as the three tunics:

1. Tunica intima (interna)
2. Tunica media
3. Tunica externa (adventitia)

The lumen is the central cavity.

Question 3

Part A

Answer 3

tunica interna (aka intima)

• innermost layer of blood vessels
• made up of three parts: simple squamous endothelium overlying basement membrane and fibrous subendothelium

Question 4

part B

Answer 4

Tunica media

• middle layer of blood vessels
• contains elastin & collagen for stretch & strength
• sheets of circularly arranged smooth muscle for vasoconstriction/dilation

Question 5

part C

Answer 5

tunica externa (adventitia)

• outermost layer of blood vessel
• areolar connective tissue
• anchors vessel to other structures

Question 6

vessels on the right

Answer 6

Arteries

• carry blood away from heart
• thicker walls and smaller lumens than veins
• higher pressure

large 2.5-1 cm

medium - 1 - 0.3 cm

smallest arteries - 0.3 mm to 10 microm.

Question 7

What are the two types of arteries and their attributes?

Answer 7

Elastic Arteries

• high elastin content within tunica media allows stretch with each pulse
• found in aorta, pulmonary arteries and their branches

Muscular Arteries

• low overall elastin content; more smooth muscle
• elastin-rich layers on either side of tunica media (elastic laminae)

Question 8

layer B

Answer 8

internal elastic lamina

• separates tunica intima from tunica media
• layer of elastic fibers in muscular arteries

Question 9

part D

Answer 9

external elastic lamina

• separates tunica media from tunica externa
• layer in muscular arteries

Question 10

What are the smallest arteries called, how big are they and how do they differ from other arteries?

Answer 10

Arterioles

• range from 0.3 mm - 10 micrometers
• large arterioles have all three tunics; small have endothelium and smooth muscle only

Question 11

What are the small vessels in which molecule exchange with tissues occurs?

How big are they and what are their layers?

Answer 11

Capillaries

• 8-10 micrometers
• no tunics; endothelium & basement membrane only

Question 12

What is this network of vessels called?

Answer 12

Capillary Bed

• a network of capillaries that vascularizes tissues and carries blood between arteries and veins

Question 13

Tissue Vascularization…

which tissues are vascular/avascular?

Answer 13

• Most tissues & organs are well vascularized
• Tendons & ligaments are poorly vascularized
• Epithelia & cartilage are avascular

Question 14

2

Answer 14

Precapillary Sphincter

• sphincters between the thoroughfare channel and the capillary bed which control capillary bed perfusion

Question 15

What is the vessel through which blood can flow directly from arteries to veins when precapillary sphincters are closed?

Answer 15

Thoroughfare Channel

Question 16

What kind of blood vessel is this?

Answer 16

Vein

• take oxygen-poor blood from capillaries to heart
• lower pressure
• thinner walls, larger lumens
• contain valves to counteract low pressure

Question 17

What are the smallest veins called?

Answer 17

Venules

• 8-100 micrometers
• postcapillary venules are smallest venules
• join to form veins

Question 18

What two mechanisms counteract low venous pressure and ensure unidirectional venous flow?

Answer 18

Valves - particularly in limbs

Skeletal muscle pump - muscles press against thin-walled veins

Question 19

What are the smaller vessels supplying the outsideof this larger vessels called?

Answer 19

vasa vasorum (vessels of vessels)

• nourish outer region (tunica externa) of larger vessels

Question 20

What are the two circulatory circuits? What are their functions and attributes?

Answer 20

• Pulmonary Circulation -
• to/from lungs
• uptake of O2, removal of CO2

**Systemic Circulation - **

• vessels on left and right of trunk are asymmetrical; head and limbs are symmetrical
• carry O2, pick up CO2
• pickup & deliver nutrients
• nitrogenous waste to kidneys
• hormone and signal molecule transport

Question 21

Describe the route of pulmonary circulation from heart to lungs and back.

Answer 21

Pulmonary trunk —->

Pulmonary arteries—->

Lobar arteries (two to left, three to right) —–>

Branches along bronchi —->

Arterioles —->

Pulmonary capillaries —->

Venules —->

Larger veins —->

Pulmonary veins —->

Superior/inferior pulmonary veins —->

Left atrium

Question 22

What are the three parts of the aorta?

Answer 22

• ascending aorta - arises from ventricle ~ 5 cm
• aortic arch - arches posteriorly to the left, has arteries branching off superiorly
• descending aorta - posterior to heart, inferiorly along thoracic/lumbar vertebrae

Question 23

What are the three branches of the aortic arch (from right to left in anatomical position) ?

Answer 23

• Brachiocephalic Trunk - branches into right common carotid and righ subclavian
• Left Common Carotid Artery
• Left Subclavian Artery

Question 24

What part of the largest artery is shown here with an aneurysm?

Answer 24

abdominal aorta

• ends at L4
• distributes blood to celiac trunk, superior and inferior mesenteric, suprarenal, renal, gonadal, inferior phrenic and common iliac arteries

Question 25

Answer 25

**right common carotid** - supplies head and neck - divides into internal/external carotid arteries

Question 26

vessel in green:

Answer 26

**internal carotid artery (left and right)** - supplies structures in skull via carotid canal - interconnected with basilar artery in circle of Willis

Question 27

Answer 27

**external carotid artery** - supplies structures external to skull (face, thyroid, tongue) - commonly used to measure pulse

Question 28

red vessel

Answer 28

**Vertebral Artery (left and right)** - supplies posterior brain - emerge from subclavians, travel through transverse foramina of cervical vertabrae - enter skull through foramen magnum - **merge into basilar artery**

Question 29

Answer 29

**right subclavian artery** - branches off of _brachiocephalic trunk_ - supplies upper limb

Question 30

What portion of this large artery is shown here with an aneurysm?

Answer 30

**thoracic aorta**

Question 31

#6

Answer 31

**axillary artery (left and right)** - "armpit" artery - supplies muscles of pectorals and axilla -

Question 32

#7

Answer 32

**brachial artery (left and right)** - supplies arm - continues down arm to antecubital fossa and branches into radial and ulnar arteries

Question 33

#17

Answer 33

**radial artery (left and right)** - supplies radial forearm - branches off of brachial artery at antecubital fossa

Question 34

#20

Answer 34

**ulnar artery (left and right)** - supplies ulnar forearm - branches off of brachial artery at antecubital fossa

Question 35

#1

Answer 35

**celiac trunk** - most superior of three unpaired branches of abominal aorta - distributes blood to _left gastric_, _splenic_ and _common hepatic_ arteries

Question 36

Answer 36

**common hepatic artery** - branches rightward off of celiac trunk toward liver - supplies liver

Question 37

marked "sa" here:

Answer 37

**splenic artery** - branches leftward off of celiac trunk toward spleen - supplies spleen, stomach and pancreas

Question 38

part B

Answer 38

**left gastric artery** - branch of celiac trunk - supplies stomach and esophagus

Question 39

indicated by red arrow:

Answer 39

**superior mesenteric artery** - middle unpaired branch of abdominal aorta - supplies pancreas, small intestine, appendix, and first 2/3 of large intestine

Question 40

indicated by red arrow:

Answer 40

**inferior mesenteric artery** - supplies last third of large intestine - most inferior unpaired branch of adominal aorta

Question 41

#8

Answer 41

**suprarenal arteries (left and right)** - supplies adrenal glands - paired branches of abdominal aorta

Question 42

arteries between aorta and kidneys:

Answer 42

**renal arteries (left and right)** - supplies kidney - paired branches of abdominal aorta

Question 43

paired arteries highlighted here:

Answer 43

**gonadal arteries (left and right)** - supplies testes in male, ovaries in female - paired branches of abominal aorta

Question 44

Answer 44

**common iliac artery (left and right)** - distributes blood to external and internal iliac arteries - supplies pelvis and lower limbs - branches off of inferior abominal aorta

Question 45

Answer 45

**external iliac artery** - supplies lower limbs - branches off of common iliac artery

Question 46

artery in green here:

Answer 46

**femoral artery (left and right)** - supplies lower abdominal wall, groin, external genitals and thigh - continuation of external iliac artery

Question 47

Answer 47

**internal iliac artery (left and right)** - extends from common iliac artery into pelvic region - supplies pelvic walls and viscera, buttock, reproductive organs and medial thigh

Question 48

vessel in green here:

Answer 48

**popliteal artery (left and right)** - supplies muscles in thigh and skin on posterior leg - extension of femoral artery

Question 49

artery highlighted pink here:

Answer 49

**anterior tibial artery (left and right)** - supplies knee joint, anterior leg muscles, anterior skin of leg and ankle joint - branch of popliteal artery

Question 50

Answer 50

**posterior tibial artery (left and right)** - supplies muscles, bones, and joints of leg and foot - branch of popliteal artery

Question 51

Answer 51

**fibular** (or **peroneal**) **artery (left and right)** - supplies lateral lower leg - branch off of posterior tibial artery

Question 52

vessel in green here:

Answer 52

**dorsalis pedis artery (left and right)** - supplies muscles, skin and joints of dorsal foot - continuation of anterior tibial artery

Question 53

What is this entire circuit of blood vessels called? What is its significance/function?

Answer 53

**Cerebral Arterial Circle** (or **Circle of Willis**) - an important _anastomosis_ of arteries around the sella turcica - equalizes blood pressure in the brain - provides collateral channels if one vessel becomes blocked

Question 54

a communication between blood vessels

Answer 54

anastomosis

Question 55

#3

Answer 55

**basilar artery** - formed by merging of l. and r. vertebral arteries - travels immediately anterior to pons - extends many branches - divides into posterior cerebral arteries

Question 56

#10

Answer 56

**anterior cerebral arteries** - supplies blood to most medial portions of frontal lobes and superior medial parietal lobes

Question 57

#7

Answer 57

**middle cerebral arteries (left and right)** - arises from internal carotid - supplies lateral cerebral cortex, anterior temporal lobes and insular cortices

Question 58

#5

Answer 58

**posterior cerebral arteries (left and right)** - supplies posterior cerebrum

Question 59

#11

Answer 59

**anterior communicating artery** - connects two anterior cerebral arteries

Question 60

#6

Answer 60

**posterior communicating artery (left and right)** - branches of posterior cerebral arteries - communicate with middle cerebral arteries

Question 61

Answer 61

**superior vena cava** - receives blood from right and left brachiocephalic veins - drains head, neck, chest and upper limbs

Question 62

#5

Answer 62

**brachiocephalic veins (left and right)** - receives blood from external jugular, vertebral and internal jugular veins - drains head, neck, upper limbs, mammary glands and superior thorax into superior vena cava

Question 63

#2 and #8

Answer 63

**internal jugular veins** (**right and left**, respectively) - drain cranium, neck and face - drain into brachiocephalic veins

Question 64

vein whose name is blacked out here:

Answer 64

**external jugular vein (left and right)** - drain neck, face, salivary glands, and scalp

Question 65

#3 and #4

Answer 65

**subclavian arteries (left and right)** - receive blood from axillary veins - drains arms, neck, thoracic wall

Question 66

area highlighted blue:

Answer 66

**axillary vein (left and right)** - drains arms, axillae, superolateral chest wall - extends into subclavian vein

Question 67

vessel indicated in green:

Answer 67

**cephalic vein (left and right)** - drains lateral surface of upper limb - on radial side of forearm as well

Question 68

Answer 68

**brachial vein (left and right)** - drains forearm, wrist and hand

Question 69

part B

Answer 69

**basilic vein (left and right)** - drains medial surface of upper limb - continues down forearm on ulnar side

Question 70

part A

Answer 70

**median cubital vein (left and right)** - drains forearm - where IVs are often given in antecubital fossa

Question 71

Answer 71

**radial vein (left and right)** - drains radial forearm - joins with ulnar vein to form brachial vein

Question 72

Answer 72

**ulnar vein (left and right)** - drains ulnar forearm - joins with radial vein to form brachial vein

Question 73

largest vessel shown here:

Answer 73

**inferior vena cava** - receives blood from hepatic, gonadal, lumbar, phrenic, suprarenal, renal and common iliac veins - drains abdomen, pelvis, lower limbs into right atrium

Question 74

the veins here labeled RHV, MHV, LHV:

Answer 74

**hepatic veins** - drains the liver

Question 75

Answer 75

**hepatic portal vein** - drains venous blood from spleen, stomach and intestines to liver for processing

Question 76

vein highlighted green here:

Answer 76

**suprarenal veins (left and right)** - drains adrenal glands

Question 77

#5

Answer 77

**renal veins (left and right)** - drains kidney

Question 78

highlighted blue here:

Answer 78

**gonadal veins (left and right)** - left drains into left renal vein, right drains into inferior vena cava - drains testes in males, ovaries in females

Question 79

highlighted vein here:

Answer 79

**lumbar veins (left and right)** - drains posterolateral abdominal wall -

Question 80

Answer 80

**common iliac veins (left and right)** - branch off of inferior end of inferior vena cava - receive blood from external and interal iliac veins - drain pelvis and lower limbs

Question 81

Answer 81

**internal iliac vein (left and right)** - drains pelvic muscles, skin, urinary and reproductive organs in pelvic cavity

Question 82

green arrows

Answer 82

**external iliac vein** - drains lower limb

Question 83

Answer 83

**femoral vein (left and right)** - drains muscles of thigh, femur, external genitals and superficial lymph nodes

Question 84

green vessel:

Answer 84

**popliteal vein (left and right)** - drain knee joint and skin, muscles, bones of calf and thigh near knee

Question 85

Answer 85

**great saphenous vein (left and right)** - drains medial leg and thigh, groin, external genitalia, abdominal wall - largest superficial vein

Question 86

starred area:

Answer 86

**superior sagittal sinus** - superior to longitudinal fissure - drains into one of transverse sinuses

Question 87

marked TS here:

Answer 87

**transverse sinus** - run in shallow grooves on internal surface of occipital bone

Question 88

dural venous sinuses

Answer 88

- several large veins that drain venous blood of cranium - formed between periosteal and meningeal layer of dura mater - receive excess CSF from arachnoid villi

Question 89

vein in blue here:

Answer 89

**splenic vein** - drains spleen - meets with inferior mesenteric vein to form hepatic portal vein - part of hepatic portal system, drains into liver before returning to heart

Question 90

Answer 90

**inferior mesenteric vein** - drains into splenic vein where they form hepatic portal vein - drains blood from large intestine into hepatic portal system for hepatic processing before return to the heart

Question 91

Answer 91

**superior mesenteric vein** - vertically positioned vein draining small intestine and part of large intestine - part of hepatic portal system

Question 92

hepatic portal system (and its veins)

Answer 92

- a venous network that drains GI blood to the liver for absorption and processing of digested materials made up of: * **splenic vein** * **inferior mesenteric vein** * **superior mesenteric vein**

Question 93

Fetal vs. Postnatal Circulation

Answer 93

- the fetus supplies blood to the placenta - very little blood sent thru pulmonary circuit because the lungs are undeveloped and non-functioning

Question 94

How does blood bypass the pulmonary circuit in fetal circulation?

Answer 94

Via the **foramen ovale,** a hole in the interatrial septum which becomes the _fossa ovalis_ after birth and via the **ductus arteriosus,** a vessel connecting the pulmonary artery and proximal descending aorta which becomes the _ligamentum arteriosum_ after birth

Question 95

How does fetal blood bypass the liver?

Answer 95

via the **ductus venosus**, which shunts umbilical vein blood flow directly to the inferior vena cava and becomes the _ligamentum venosum_ after birth

Question 96

How does the fetus drain blood to the placenta?

Answer 96

- via the paired **umbilical arteries** which run from the abominopelvic region of the fetus into the umbilical cord - they become the _medial umbilical ligaments_ after birth

Question 97

How does the fetus receive blood supply from the placenta?

Answer 97

via the unpaired **umbilical vein** which carries oxygenated blood to the fetus and becomes the _ligamentum teres_ after birth