Blood Vessels

Question 1

types of blood vessels (and diameters)

Answer 1

elastic arteries (1 - 2.5cm)
muscular arteries (0.3 mm - 1 cm)
arterioles (10 um - 0.3 mm)
capillaries (8 - 10 um)
venules (8 - 100 um)
veins

Question 2

layers of arteries

Answer 2

lumen - blood filled inner space
tunica intima
tunica media
tunica externa

Question 3

tunica intima

Answer 3

endothelium made up of simple squamous epithelium
subendothelial layer
internal elastic membrane

Question 4

tunica media

Answer 4

sheets of smooth muscle and elastic fibers
external elastic membrane
contraction causes vasoconstriction, relaxation causes vasodilation

Question 5

tunica externa

Answer 5

composed of collagen fibers

Question 6

elastic arteries

Answer 6

for conducting blood
largest arteries
diameter 1-2.5 cm
high elastin content: dampens surge of blood pressure
walls of vessels supplied by vasa vasorum
proximal to muscular arteries

Question 7

muscular arteries

Answer 7

for distributing blood
lie distal to elastic arteries
diameter 0.3 mm - 1 cm
tunica media is thick, smooth muscle and elastin fibers
unique feature: internal and external elastic membranes that dampen the pulsatile pressure produced by the heartbeat

Question 8

arterioles

Answer 8

smallest arteries
diameters 10 um - 0.3 mm
larger arterioles possess the same tunics
diameter of arterioles controlled by: local factors in the tissues, autonomic nervous system

Question 9

capillaries

Answer 9

smallest blood vessels
diameter 8 - 10 um
red blood cells pass through single file
site specific functions

Question 10

site-specific functions of capillaries

Answer 10

lungs: oxygen enters blood, carbon dioxide leaves blood
other tissues: oxygen leaves blood, carbon dioxide enters blood
small intestines: receive digested nutrients
endocrine glands: pick up hormones
kidneys: remove nitrogenous and other wastes

Question 11

poorly vascularized tissues

Answer 11

tendons and ligaments are poorly vascularized

epithelia and cartilage are avascular

Question 12

precapillary sphincters

Answer 12

regulate the flow of blood to tissues
when relaxed, sphincters are open and blood flows to true capillaries
when constricted, sphincters are closed and blood flows to metarteriole thoroughfare channel and bypasses the capillaries

Question 13

types of capillaries

Answer 13

continuous capillaries - the least permeable type of capillaries
fenestrated capillary - large fenestrations (pores) increase permeability in small intestines and kidneys
sinusoidal capillary - most permeable with wide intercellular clefts in bone marrow, liver, and spleen

Question 14

continuous capillaries

Answer 14

most common type
relatively low permeability
found in skin, muscle, blood-brain barrier
capillaries have complete tight junctions of endothelial cells which prevent movement
vital molecules pass through via highly selective transport mechanisms (endothelial cell membranes and pinocytotic vesicles)
not a barrier against: oxygen, carbon dioxide, some drugs

Question 15

where are continuous capillaries found?

Answer 15

skin, muscle, blood-brain barrier

Question 16

pericytes around continuous capillaries

Answer 16

contractile cells that wrap around endothelial cells, embedded in basement membrane
communicate with and help sustain endothelial cells

Question 17

fenestrated capillaries

Answer 17

large fenestrations (pores) result in increased permeability
found in kidneys and small intestines

Question 18

sinusoidal capillaries

Answer 18

most permeable capillaries
wide open intercellular clefts (gaps of unjoined membrane through which small molecules can enter and exit)
usually also fenestrated
incomplete basement membrane
have a large diameter and twisted course
found in bone marrow, liver, and spleen

Question 19

where are fenestrated capillaries found?

Answer 19

small intestine, kidneys

Question 20

where are sinusoidal capillaries found?

Answer 20

liver, bone marrow, spleen

Question 21

routes of permeability in capillaries

Answer 21

1. endothelial cell membranes
2. pinocytotic vesicles
3. fenestrations (fenestrated capillaries)
4. intercellular clefts (sinusoidal capillaries)

Question 22

smallest venules are called

Answer 22

postcapillary venules

Question 23

thickest tunic in veins

Answer 23

tunica externa

rich in collagen fibers

Question 24

mechanisms to move venous blood

Answer 24

valves - in some valves, prevent backflow of blood, particularly in limbs
skeletal muscles - press against vein walls and help pump blood toward the heart

Question 25

vascular anastomoses

Answer 25

vessels interconnect to form vascular anastomoses that enable organs to receive blood from more than one blood vessel veins anastomose more than arteries

Question 26

vasa vasorum

Answer 26

vessel of vessels tiny arteries, capillaries, and veins nourish outer region (tunica externa) of large vessel walls the inner half of large vessels receive nutrients from luminal blood

Question 27

pulmonary circulation

Answer 27

pulmonary trunk extends from right ventricle, divides into right and left pulmonary arteries, and carries deoxygenated blood to the lungs superior and inferior pulmonary veins carry oxygenated blood into the left atrium

Question 28

systemic arteries

Answer 28

carry oxygenated blood away from the heart | the aorta, for example

Question 29

aorta

Answer 29

largest artery in the body ascending aorta arises from the left ventricle and early branches form coronary arteries aortic arch lies posterior to manubrium descending aorta continues from the aortic arch divides into right and left common iliac arteries

Question 30

aortic arch

Answer 30

lies posterior to the manubrium brachiocephalic trunk: right subclavian and common carotid arteries left common carotid artery left subclavian

Question 31

descending aorta

Answer 31

continues from the aortic arch thoracic aorta in the region of T15-T12 abdominal aorta ends at L4

Question 32

common carotid arteries

Answer 32

located in anterior triangle of neck | 2 branches: external and internal

Question 33

external common carotid artery branches

Answer 33

``` maxillary artery facial artery lingual artery superficial temporal artery occipital artery superior thyroid artery ```

Question 34

internal common carotid artery branches

Answer 34

ophthalmic artery middle cerebral artery anterior cerebral artery posterior communicating artery

Question 35

cerebral artery circle (circle of Willis)

Answer 35

forms a loop around pituitary gland and optic chiasm anterior blood supply from internal carotids posterior blood supply from vertebral arteries

Question 36

vertebral arteries

Answer 36

supply blood to posterior part of brain extend off subclavian artery and ascend through foramina in transverse processes of cervical vertebrae C1-C6 merge to form basilar artery, splits into posterior cerebral arteries

Question 37

arteries of the arm

Answer 37

subclavian --> axillary --> brachial --> radial/ulnar --> superficial/deep palmar arch, digital arteries

Question 38

axillary artery becomes the brachial artery at the

Answer 38

inferior border of teres major muscle

Question 39

arteries of the thorax

Answer 39

anterior and posterior intercostal arteries | lateral and internal thoracic arteries

Question 40

arteries of the abdominal aorta

Answer 40

``` inferior phrenic celiac trunk superior mesenteric suprarenal renal gonadal inferior mesenteric common iliac ```

Question 41

celiac trunk

Answer 41

main branches supply the viscera in superior abdomen | 3 main branches: left gastric, splenic, common hepatic

Question 42

superior mesenteric artery

Answer 42

arteries extend to jejunum, ileum, proximal half of colon (cecum, appendix, ascending colon, first half of transverse colon)

Question 43

inferior mesenteric artery

Answer 43

arteries extend to distal half of colon (second half of transverse colon, descending colon, sigmoid colon, rectum)

Question 44

artery branches off the internal iliac

Answer 44

``` gluteal obturar internal pudendal middle rectum visceral uterine ```

Question 45

arteries of the pelvis and lower limbs

Answer 45

``` internal iliac external iliac femoral popliteal anterior tibial posterior tibial fibular dorsalis pedalis plantar plantar arch ```

Question 46

3 major veins enter the right atrium

Answer 46

``` superior vena cava (returns blood from structures superior to diaphragm) inferior vena cava (returns blood from structures inferior to diaphragm) coronary sinus (returns blood from cardiac muscle) ```

Question 47

coronary sinus

Answer 47

supplies right atrium receives blood via coronary sinus in posterior coronary sulcus drains from great, middle, and small cardiac veins

Question 48

dural sinuses in brain

Answer 48

venous channels found between periosteal dura and the brain walls of the dural venous sinuses are lined with endothelium internal jugular vein drains the venous sinuses

Question 49

dural sinuses in the head and neck

Answer 49

``` super and inferior sagittal sinuses straight sinus cavernous sinus transverse sinus sigmoid sinus ```

Question 50

deep veins of the upper limbs

Answer 50

``` subclavian axillary brachial basilic cephalic radial ulnar deep palmar arch digital ```

Question 51

superficial veins of the upper limbs

Answer 51

basilic cephalic median cubital (site of blood draw) median antebrachial

Question 52

veins of the thorax

Answer 52

azygos hemiazygos accessory hemiazygos intercostals

Question 53

veins of the abdomen

Answer 53

``` inferior phrenic hepatic suprarenal renal lumbar gonadal ```

Question 54

hepatic portal system

Answer 54

specialized part of the vascular circuit picks up digested nutrients from the stomach and intestine and delivers nutrients to the liver for processing and storage

Question 55

veins that supply the hepatic portal system

Answer 55

``` gastric gastroepiploic splenic inferior mesenteric superior mesenteric ```

Question 56

first capillary bed of hepatic portal system

Answer 56

in the stomach and intestines | receives digested nutrients and then drains into hepatic portal veins

Question 57

second capillary bed of hepatic portal system

Answer 57

liver sinusoids nutrients reach liver cells for processing (still oxygen-poor) blood then reenters systemic circulation

Question 58

superficial veins of the pelvis and lower limbs

Answer 58

small saphenous great saphenous arise from the dorsal venous arch

Question 59

deep veins of the pelvis and lower limbs

Answer 59

``` iliac femoral popliteal anterior tibial posterior tibial fibular dorsalis pedalis plantar plantar arch digital ```

Question 60

aneurysm

Answer 60

dilation of blood vessel wall that may burst

Question 61

example of venous disease

Answer 61

varicose veins

Question 62

atherosclerosis

Answer 62

fat deposits in arteries