Post on 14-Apr-2018
7/27/2019 Lecture 19 - Vessels and Circulation
1/67
Vessels and Circulation
7/27/2019 Lecture 19 - Vessels and Circulation
2/67
2
Some embryology
first
There are at first sixpairs of aorticarches
In fish these areconnected to thegills
They undergo atransformation inmammals Birds use the right
arch of the fourth pair Mammals use the
left arch of thefour th pair
http://upload.wikimedia.org/wikipedia/commons/f/f7/Gray472.png7/27/2019 Lecture 19 - Vessels and Circulation
3/67
3
Ventral (anterior)
view
Full set of arches develops,
but not all present at
the same time; (before
transformation)
Transformation :
4th through 7th
weeks: some persist,
some atrophy
http://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.png7/27/2019 Lecture 19 - Vessels and Circulation
4/67
4
R
ight common carotid a ------------------------------.
Right subclavian a. --------------------------
Brachiocephalic trunk-----------------------------------
4th arches become:
Left side: aortic arch
Right side: brachiocephalic trunk
http://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.png7/27/2019 Lecture 19 - Vessels and Circulation
5/67
5
What the aortic
arches become
Right common
carotid a ---------------------------.
Right subclavian a. ---------------------------
Brachiocephalic trunk-------------------------------
http://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/Gray473.png7/27/2019 Lecture 19 - Vessels and Circulation
6/67
6
3 Major types of
blood vessels
Body
RA
RV
Lungs
LA
LV
Boby
1.Arteries
2.Capillaries
3.Veins
Arteries carry blood awayfrom the heart
-branch, diverge or forkVeins carry blood towardthe heart
-join, merge, converge
7/27/2019 Lecture 19 - Vessels and Circulation
7/67
7
General characteristics of vessels
Three layers (except for the smallest)
1. Tunica intima - AKA intima
2. Tunica mediasmooth muscle
3. Tunica externa - AKA adventitia
Lumen is the central blood filled space
7/27/2019 Lecture 19 - Vessels and Circulation
8/67
8
Intima is endothelium (simple squamous epithelium) May have subendothelial layer if 1mm or larger
Tunica media: layers of circular smooth muscles Lamina (layers) of elastin and collagen internal and external
Thicker in arteries than veins (maintain blood pressure)
Smooth muscle
contraction:
vasoconstriction
Smooth muscle
relaxation:
vasodilation
Sympatheticvasomotor
nerves of
autonomic
nervous system
regulate
7/27/2019 Lecture 19 - Vessels and Circulation
9/67
9
Adventitia (t. externa) longitudinally running
collagen and elastin for strength and recoil
7/27/2019 Lecture 19 - Vessels and Circulation
10/67
10muscular middle sized artery
7/27/2019 Lecture 19 - Vessels and Circulation
11/67
11
Arteries Carry blood away from the heart
From big to small, these are the categories:1. Elastic
2. Muscular
3. Arter io les(then these to capillaries)
Pressure diminishes along the route
1. Elast ic arteries: act as condui ts 2.5-1 cm diameter
Expand with surge
of blood from heart
Recoil and continue
the propagation of blood
Elastin is thick in media:
dampens the surge of blood
pressure
Aorta and i ts branches
7/27/2019 Lecture 19 - Vessels and Circulation
12/67
12
Arteries continued
2. Musculararteries: act as
distr ibut ingarteries
Middle sized .3mm-1cm
Changes diameter todifferentially regulate flow
to organs as needed
Internal as well as
external elastic lamina Most of what we see as
arteries
Tunica media larger in proportion
to the lumen, thus muscular
7/27/2019 Lecture 19 - Vessels and Circulation
13/67
13
Arteries continued
3. Arter ioles Smallest: .3mm-10um
Only larger ones have all 3layers
Regulated 2 ways: Locally in the tissues
Sympathetic control
Systemic blood pressure (theBP we measure) can be
regulated through them Send blood into capillaries
Tunica media has only a few
layers of smooth muscle cells
7/27/2019 Lecture 19 - Vessels and Circulation
14/67
14
Capillaries
Heart to arteries to capillaries to veins to heart
Capillaries are smallest 8-10um
Just big enough for single file erythrocytes
Composed of: single layer of endothelial cells surroundedby basement membrane
Universal function Oxygen and nutrient delivery to tissues
CO2 and nitrogenous waste (protein break-down product)removal
Some also have tissue specific functions
7/27/2019 Lecture 19 - Vessels and Circulation
15/67
15
Capillaries
Theres a capillary bed in almost all tissues
7/27/2019 Lecture 19 - Vessels and Circulation
16/67
16
7/27/2019 Lecture 19 - Vessels and Circulation
17/67
17
Capillary permeability
Direct diffusion through endothelial cell
membranes
Only O2 and CO2
Other molecules by various other methods
Blood brain barrier: complete tight junctions
Selective transport of necessary molecules
Lipid soluble agents (like anesthetics) get
through, as do O2 and CO2
7/27/2019 Lecture 19 - Vessels and Circulation
18/67
18
Veins
Pressure has been lowered so capillariescan tolerate
With lower pressure, walls (of veins) can
be thinner From smallest to large:
Capillaries to postcapillary venules to venules toveins
Veins are larger than arteries, plus
Tunica externa is thicker
There is less elastin
7/27/2019 Lecture 19 - Vessels and Circulation
19/67
19
Special features of veins
Valves
Prevent backflow
Most abundant in legs (where
blood has to travel againstgravity) Muscular contraction
Aids the return of blood to heart in
conjunction with valves
Mechanical issues
(really good to know)
7/27/2019 Lecture 19 - Vessels and Circulation
20/67
20
Exercise helpscirculation
(because
muscles
contract andsqueeze blood
back to the
heart)
7/27/2019 Lecture 19 - Vessels and Circulation
21/67
21
Vascular anastomoses
Vessels communicating with each other Veins have more than arteries
Form alternative pathways or collateral channels
Protect organs from being supplied by just oneroute Poor anastomoses & therefore vulnerable: central
artery of retina, kidneys, spleen, bone diaphyses
Vasa vasorum Means vessels of the vessels
Blood supply to vessel itself
Smallest vessels dont need
7/27/2019 Lecture 19 - Vessels and Circulation
22/67
22
Vascular System
(Blood vessels of the body)
Two circulations
Systemic
Pulmonary
Arteries and veins usually run together
Often nerves run with them
Sometimes the systems do not have bilateralsymmetry
In head and limbs, most are bilaterally symmetrical
7/27/2019 Lecture 19 - Vessels and Circulation
23/67
23
Pulmonary Circulation
Pulmonary trunk branches Right and left pulmonary arteries
Division into lobar arteries 3 on right
2 on left
Smaller and smaller arterioles, into capillaries surrounding alveoli Gas exchange
Pulmonary system pressure is only 1/6 of systemic blood pressure
7/27/2019 Lecture 19 - Vessels and Circulation
24/67
24
Pulmonary Circulation
After gas exchange blood enters venules
Larger and larger into Superior and Inferior
Pulmonary veins
Four Pulmonary Veins empty into left atrium
7/27/2019 Lecture 19 - Vessels and Circulation
25/67
25
7/27/2019 Lecture 19 - Vessels and Circulation
26/67
26
In lungs
7/27/2019 Lecture 19 - Vessels and Circulation
27/67
27
Systemic Circulation
Oxygenated blood to body
Leaves LV through Ascending Aorta
Only branches are the 2 coronary arteries to the heart
Aortic Arch has three arteries branching from it:1. Brachiocephalic trunk, has 2 branches:
Right common carotid a. Right subclavian a.
2. Left common carotid a.
3. Left subclavian a.
Ligamentum arteriosumconnecting to pulmonary a.
remember aortic arches
7/27/2019 Lecture 19 - Vessels and Circulation
28/67
28
Descending aorta
Thoracic aorta
at T12 becomes
abdominal aorta
Abdominal aorta
ends at L4
branching into:
R & L commoniliac arteries
7/27/2019 Lecture 19 - Vessels and Circulation
29/67
29
Commoncarotids branch: Internal carotids
External carotids
Subclavian: 3branches Vertebral
arteries
Thyrocerical
trunk Costocervical
trunk
7/27/2019 Lecture 19 - Vessels and Circulation
30/67
30
Head and neck
Common carotids justlateral to trachea: feel At larynx divides into
internal & external
External carotid:supplies headexternal to brain andorbit Feel superficial
temporal a.
Middle meningeal:
vulnerable (branch ofmaxillary)
Internal carotid Supply orbits and
most of cerebrum
7/27/2019 Lecture 19 - Vessels and Circulation
31/67
31
Internal carotid a.
Enters skullthrough carotid
canal
Gives off:
Ophthalmic artery
Then divides into
anterior and middle
cerebral arteries(see next slides):
together they supply
80% o f cerebrum
7/27/2019 Lecture 19 - Vessels and Circulation
32/67
32
7/27/2019 Lecture 19 - Vessels and Circulation
33/67
33
7/27/2019 Lecture 19 - Vessels and Circulation
34/67
34
Angiogram
7/27/2019 Lecture 19 - Vessels and Circulation
35/67
35
Middle cerebral
arteries run throughlateral fissures
Anterior cerebralarteries of each
side, throughanteriorcommunicatingartery, anastomose
(an anastomosis is a union)
arteriogram
7/27/2019 Lecture 19 - Vessels and Circulation
36/67
36
R and L vertebral arteries* (from subclavians) Ascend through vertebral foramina of C6-C1
transverse processes
Through foramen magnum into skull
Join to form one Basilar artery*
*
*
*
*
7/27/2019 Lecture 19 - Vessels and Circulation
37/67
37
Basilar artery: branches Divides into posterior cerebral arteries
Posterior communicating arteries connect tomiddle cerebral arteries
CIRCLE OF WILLIS(now called cerebral arterial circle)
Note how it loops
around pituitary
gland & optic chiasm
7/27/2019 Lecture 19 - Vessels and Circulation
38/67
38
7/27/2019 Lecture 19 - Vessels and Circulation
39/67
39
Upper limb
Subclavian runslaterally onto 1st rib,under clavicle
Enters axilla asaxillary artery Sends branches
Continues asbrachial artery inupper arm
Splits into radial &ulnararteries
See hand supply
Feel brachial & radial puls es
7/27/2019 Lecture 19 - Vessels and Circulation
40/67
40
overview
7/27/2019 Lecture 19 - Vessels and Circulation
41/67
41
overview
7/27/2019 Lecture 19 - Vessels and Circulation
42/67
42
Thorax
Anterior intercostalsbranch off Internalthoracic*(branch ofsubclavian)
Posterior
intercostals branchoff Thoracic aorta
Intercostal arteries,veins and nervesrun just UNDERtheribs
Small bronchial
arteries supply the
lung structures
*
A t i t th bd
7/27/2019 Lecture 19 - Vessels and Circulation
43/67
43
Arteries to the abdomen
Arise from the abdominal aorta
At rest, arterial blood is here!
Three single midline branches supply the digestive tube1. Celiac trunk2. Superior mesenteric artery
3. Inferior mesenteric artery
1.
2.
3.
7/27/2019 Lecture 19 - Vessels and Circulation
44/67
44
1. Celiac trunk: divides into 3 right away: left gastric,splenic & common hepatic (see pic; the latter isthe only which goes off to the right)
2. Superior mesenteric supplies most of intestines
1.
2.
Definition of mesenteries: double layered sheets of peritoneum
that support most organs in the abdominopelvic cavity
7/27/2019 Lecture 19 - Vessels and Circulation
45/67
45
3. Inferior mesenteric supplies distal half of
large intestine
2.
3.
1.
Know what these terms mean: phrenic, gastric, hepatic, renal, colic
(The 1, 2 and 3 are branches of the abdominal aorta)
A t i t th bd
7/27/2019 Lecture 19 - Vessels and Circulation
46/67
46
Arteries to the abdomen
Paired branches off the abdominal aorta
supply adrenal glands, kidneys, gonadsand abdominal body wall
supp ly
diaphragm
3.
supp ly
adrenals
to kidney
7/27/2019 Lecture 19 - Vessels and Circulation
47/67
47
7/27/2019 Lecture 19 - Vessels and Circulation
48/67
48
Abdominal aortabranches into
Common iliacs atL4; these branchinto Internal iliacs to
pelvic organs,
perineum,buttocks, medialthighs
External iliacs: to
rest of lower limbs
7/27/2019 Lecture 19 - Vessels and Circulation
49/67
49
External iliac
passes under
inguinal ligamentbecoming Femoral
artery
At back of knee
femoral becomes
popliteal artery,
and branches
Feel dorslis pedis &
posterior tibial
7/27/2019 Lecture 19 - Vessels and Circulation
50/67
50
review
7/27/2019 Lecture 19 - Vessels and Circulation
51/67
51
review
7/27/2019 Lecture 19 - Vessels and Circulation
52/67
52
review
7/27/2019 Lecture 19 - Vessels and Circulation
53/67
53
Systemic Veins
3 major vessels enter Right Atrium: SVC (superior vena cava)
IVC (inferior vena cava)
Coronary sinus Many veins are very superficial (unlike
arteries)
Venous plexuses (networks of anastomosesand parallel veins) are very common
Head and hepatic portal systems are unusual
7/27/2019 Lecture 19 - Vessels and Circulation
54/67
54
Dural sinuses
Drain the veins of
the brain Cavernous sinuses
Carotid arteries andsome cranial nerves
run within them Dangerous if trauma
Come together assigmoid sinus
becomes InternalJugularvein Exits skull throughjugular foramen
Internal jugular veins
7/27/2019 Lecture 19 - Vessels and Circulation
55/67
55
Internal jugular veins Drain most of blood from brain
Run lateral to internal then common carotid
At base of neck joins subclavian v. to form brachiocephalic v.
External jugulars drain some of scalp & face
Vein
7/27/2019 Lecture 19 - Vessels and Circulation
56/67
56
Vein
overview
Azygos system
drains the thorax:
Note that unlike the arteries, the veinshave a brachiocephalic on the right
and left sides
7/27/2019 Lecture 19 - Vessels and Circulation
57/67
57
Deep veins of
upper limbs followarteries, most ofthem double toone artery
Superficial veins:see pic
Blood drawn frommedian cubitalvein in antecubitalfossa
(look at)
Tributaries of IVC: note asymmetry
7/27/2019 Lecture 19 - Vessels and Circulation
58/67
58
Tributaries of IVC: note asymmetry Left gonadal and suprarenal veins drain into left renal
vein
On right they drain directly into IVC Right and left hepatic veins enter superior part of IVC
Hepatic portal system
7/27/2019 Lecture 19 - Vessels and Circulation
59/67
59
Hepatic portal system Picks up digested nutrients from stomach & intestines and delivers them
to liver for processing and storage Storage of nutrients
Detoxification of toxins, drugs, etc.
Two capillary beds Route: artery to capillaries of gut to hepat ic po rtal veinto livers
capillaries to hepatic vein to IVC
Dont confuse hepat ic veinwith hepat ic porta l vein
7/27/2019 Lecture 19 - Vessels and Circulation
60/67
60
Kind of confusing
Superior mesenteric
and splenic veins jointo form hepatic
portal vein, which
goes up into liver
Inferior mesenteric
empties into the
splenic vein*
*
(same info with different pic)
7/27/2019 Lecture 19 - Vessels and Circulation
61/67
61
Hepatic portal system Picks up digested nutrients from stomach & intestines
and delivers them to liver for processing and storage Storage of nutrients
Detoxification of toxins, drugs, etc.
Two capillary beds
Route: artery to capillaries of gut to hepatic portalveinto livers capillaries to hepatic vein to IVC
( p )
Tributaries of hepatic
portal vein:
-superior mesenteric vein-splenic vein-inferior mesenteric vein
7/27/2019 Lecture 19 - Vessels and Circulation
62/67
62
Leg veins
7/27/2019 Lecture 19 - Vessels and Circulation
63/67
63
Leg veins Names similar to
arteries
Femoral becomesexternal iliac after
crossing under
inguinal ligament
External iliac joins
with internal iliac to
form common iliacvein
_________used for grafting in coronary
artery bypass grafts: is the
longest vein in the body
Fetal
7/27/2019 Lecture 19 - Vessels and Circulation
64/67
64
Fetal
Circulation
The one umbilicalvein brings bloodwhich has been tothe placenta foroxygenation (by gasdiffusion from momsblood)
The pair of umbilicalarteries (branchesfrom babys internaliliac arteries) carryblood to placenta to
pick up oxygen andnutrients
Fetal heart startsbeating at 21 dayspost conception
7/27/2019 Lecture 19 - Vessels and Circulation
65/67
65
7/27/2019 Lecture 19 - Vessels and Circulation
66/67
66
7/27/2019 Lecture 19 - Vessels and Circulation
67/67
Some Diseases
Atherosclerotic cardiovascular disease Cerebrovascular disease affects brain, strokes
Coronary artery disease (CAD) arteries of heart
Peripheral vascular disease (PVD) arterial
Affecting veins Chronic venous insufficiency venous = veins
Deep venous thrombosis (DVT)
Aneurysms Portal hypertension
Hypertension