MS-1 FUND 1: 11:10-12:00
Wednesday, September 10, 2014
Dr. Zehren
Introduction to the Cardiovascular system
Transcriber: Jinwoo Hur
Editor: Victoria Underwood
Page 1 of 7
Abbreviations: GI=gastrointestinal L=lumbar
Introductory Comments: This lecture is an overview of the cardiovascular system. It shows general blood flow of the
body, difference between arteries and veins, overview of various arteries and veins in our body. Time stamp corresponds
with echo.
I.
II.
III.
Pattern of blood flow through the heart (slide 6, 05:00)
a. Heart has 4 chambers: right atrium, right ventricle, left atrium, left ventricle
b. All of unoxygenated blood returns to the right atrium enters the right ventricle pumped out to the
lungs through the pulmonary truck and arteries oxygenated blood returns to the left atrium by 4
pulmonary veins (2 on the left 2 on the right)  passes to the left ventricle pumped out through the
aorta
i.
Aorta to the head and neck by the large arteries that come off the arch of the aorta
ii.
Aorta to the trunk and lower limbs through the descending aorta
c. Valves
i.
Tricuspid
ii.
Bicuspid (mitral valve)
iii.
Tricuspid and Bicuspid values separates the ventricles and the atria to prevent reflux into
the atria
1. When ventricle contract, want blood go out of the pulmonary truck or aorta and
not refluxing into the atria
iv.
Pulmonary valve-guard entrance to pulmonary truck
v.
Aortic valve-guard entrance to the aorta
1. When ventricles relax, don’t want blood that just that has just been pumped out
of the pulmonary truck or aorta refluxing back into the ventricle
vi.
Main function of the values are just to maintain a one way flow
Arteries vs Veins
a. Arteries (slide 7, 07:00)
i.
Vessels that carry blood away from the heart
ii.
Mostly have oxygen in them (except pulmonary artery and pulmonary trunk)
iii.
Arteries branch into smaller vessels with smaller lumina as they go away from the heart
b. Veins (slide 8, 7:30)
i.
Veins carry blood towards the heart
ii.
Vein carries deoxygenated bloods (except the pulmonary vein)
iii.
Veins have tributaries rather than branches
1. Analogy: Small creeks drain into small stream. The small streams unit and form a
river and river goes back to lake
How to distinguish arteries from veins (slide 10, 08:00)
a. Similarities: have 3 layer
i.
Tunica intima: (all arteries and all veins contain)
1.
Inner most layer of single flattened endothelium
2.
Site of blood clot if vessel gets torn
ii.
Tunica media:
1.
Has smooth muscle (all vessel other than capillaries have smooth muscle)
2.
Contraction that smooth muscle is going to determine the size of the lumen of the
vessel and blood pressure
iii.
Tunica adventitia
1.
Connective tissue layer that contains small vessels and nerves
2.
Nerves supply the smooth muscle in the tunica media causing contraction of the
media
3.
The small vessels (vaso vasorum) supply nourishment
a. Only the endothelium cells that are closest to the blood can get their
nourishment directly from the blood. The other layers of arteries and vein will
need their own blood supply (vaso vasorum)
b. Difference
MS-1 FUND 1: 11:10-12:00
Wednesday, September 10, 2014
Dr. Zehren
Introduction to the Cardiovascular system
Transcriber: Jinwoo Hur
Editor: Victoria Underwood
Page 2 of 7
Abbreviations: GI=gastrointestinal L=lumbar
i.
IV.
V.
VI.
Thickness of tunica media (main criteria if it is a vein or artery)
1.
Tunica media in the artery is much thicker (wall of the arteries will tend to retain
its tubular structure as oppose to the vein )
2.
The walls of vein collapse on themselves and they appear flatter in appearance
ii. Smallest arteries are arterioles and smallest veins are
venules
iii.
Capillaries
1.
Connect arterioles and venules together
2.
Only have tunica intima (endothelium lining)-> exchange of nutrients and gases
with tissues in capillaries bed
Motor Nerve Supply (slide 12, 11:30)
a. Blood vessels have motor and a sensory nerve supply
b. All blood vessels with smooth muscle in their wall have a sympathetic nerve supply (exception:
capillaries)
i.
The sympathetic nerve fiber runs along the wall of the blood vessels
1.
Good example is in the neck. The major arteries in the neck are vertebral artery
and internal/external carotid artery. They all have a plexus (network) of
sympathetic fibers running along the walls of them. These are vasomotor fibers
and they’re going to innervate smooth muscle of the tunica media
ii.
The sympathetic fibers use the arteries as a vehicle to get to other structure.
1.
Sweat gland in the skin: The sympathetic fibers travel along the arteries and
jump off to get to the sweat gland or smooth muscle in the skin (arrector pili
muscle)
2.
So arteries have sympathetic fiber running with them: sympathetic plexus.
c. Sympathetic plexus
i.
Most are for vasoconstriction causing vasoconstriction to the arteries
1.
Exception is coronary artery. Under sympathetic stimulation you want increased
blood flow to the heart. The sympathetic stimulation to the coronary artery
causes dilation instead of constriction
ii.
Most blood vessels don’t have parasympathetic nerve supply
1.
Exception: coronary arteries (parasympathetic supply that is vasoconstrictor)
and arteries in the external genitalia (parasympathetic innervation cause dilation
of the arteryerection)
Sensory Nerve Supply (slide 13, 13:15)
a. monitor pain
b. monitor blood pressure
i.
Good example is at the base of the internal carotid artery in the neck (artery that supplies
the brain). Proximal part of the artery is dilated called carotid sinus. There is nerve called
the carotid sinus nerve that have its ending embedded in the carotid sinus. Nerve
endings are called baroreceptors (pressoreceptor)
ii.
Baroreceptors are sensitive changes in blood pressure
iii.
If blood vessel gets too high or too low afferent pulse to the brain via 9th cranial
nervebrain elicits heart reflex contract more or less forcefully to counteract to change
in blood pressure
Arterial Anastomoses (slide 15, 14:30)
a. Anastomoses means “joining”
b. Arteries, veins, and nerves can all anastomose or join with one another
c. You frequently find around major joints like the elbow joint
d. Provide a mean by which blood can bypass an obstruction (called collateral circulation)
i.
When you are moving part of the body like the upper limb, don’t want to cut off blood
supply to more distal parts (holding body part in certain orientation for long time, risk of
kinking blood vessel which may cut off circulation to more distal body part)collateral
circulation help avoid this
ii.
Example: in the arm you have brachial artery that divides into ulnar and radial arteries at
the cubical fossa that continues down to the arm to supply the hand. If there is an
MS-1 FUND 1: 11:10-12:00
Wednesday, September 10, 2014
Dr. Zehren
Introduction to the Cardiovascular system
Transcriber: Jinwoo Hur
Editor: Victoria Underwood
Page 3 of 7
Abbreviations: GI=gastrointestinal L=lumbar
occlusion at the brachial artery, the collateral anastomoses coming from the brachial
artery which anastomose with the recurrent artery in the ulnar/radial artery will allow
blood to bypass the occlusion
e. Factors that determine if there is enough blood supply during occlusion
i.
How many arteries that are involved
ii.
How large are those arteries
iii.
How sudden is the occlusion
1.
Example: if the occlusion is slow like in a blood clot, then these anastomotic
vessels can enlarge overtime and supply enough blood
2.
Example: if occlusion is fast like in fracture of the distal humerus causing the
brachial to spasm and close off, collateral and recurrent anastomoses might not be able
to be sufficient
iv.
Always take note if there is anastomosis between vessels. At least there is potential for
collateral circulation
VII.
How venous blood returns to the heart (slide 17, 18:30)
a. Especially with regard to the limb because venous blood has to work against gravity
b. One way blood return to the heart is through: musculovenouse pump
i.
When muscles contract, they swell and put pressure on the deep veins of limb and forces
venous blood to the heart.
ii.
Reason why they don’t flow away from the heart: Inside the veins of the limb they have
bicuspid valve to prevent reflux
c. Head/neck have few or no valve because you don’ need them (gravity will usually drain those back to
the heart unless you are standing on your head)
ARS Question at 19:28
VIII.
Brain (slide 20-21, 20:30)
a. Main supply is right/left vertebral arteries and right/left internal carotid artery
i.
Vertebral arteries (passes through the cervical vertebral on its way up) enter the skull
through the foramen magnum
ii.
Internal carotid arteries enter petrous temporal bone through the carotid canal
iii.
Inside the cranial cavity, vertebral arteries and internal carotid arteries unite becomes an
arterial circlebranches off the circle will supply the brain
iv.
External carotid branches supplies to the outside of the skull and neck
1. “SALFOPSM” nemonic to remember the names of the branches of external carotid
in the order of branching (8 total): Superior thyroid a., Ascending pharyngeal a.,
Lingual a., Facial a., Occipital a., Posterior auricular a., Superficial temporal a., and
Maxillary. These arteries distribute to the areas their names suggest.
IX.
Upper limb (slide 23, 22:15)
a. Main artery is the subclavian artery
i.
Arches under the clavicle and over the 1st rib
ii.
There is asymmetry between the left and right subclavian artery
1.
The right subclavian artery is a branch of the brachiocephalic trunk (brachio:arm;
cephalic:head)
2.
Brachiocephalic trunk supplies the upper limb and the head. Does this by dividing
into the subclavian artery and common coratid artery
3.
Subclavian artery, as it arches over the first rib, can be compressed to control
bleeding downstream (elastration of axillary or brachial artery)
iii.
Major arteries will often change their name as they pass down the limb or some other
part of the body (example: outer boarder of 1st rib to change name to axillary artery
cause lie in the axilla/armpit). When it enters the arm proper it is called brachial artery.
Then comes to the cubital fossa where it divides into radial and ulnar
iv.
Usually arteries and nerves will change name as they go from one region to another
X.
Thorax (slide 25-26, 24:30)
a. Pulmonary trunk & 2 pulmonary artery carry unoxygenated blood to lung
i.
Branches of the pulmonary artery goes to alveoli of the lungs (this is where gas exchange
occurs)
MS-1 FUND 1: 11:10-12:00
Wednesday, September 10, 2014
Dr. Zehren
Introduction to the Cardiovascular system
Transcriber: Jinwoo Hur
Editor: Victoria Underwood
Page 4 of 7
Abbreviations: GI=gastrointestinal L=lumbar
ii.
iii.
XI.
XII.
Each alveolus has a capillary plexus
Pulmonary artery feeds unoxygenated blood to the capillary plexus -> oxygenated blood
will return via tributary to pulmonary vein which will go back towards the heart
b. Bronchial arteries and veins
i.
Supply non respiratory part of the bronchial tree (parts that don’t have aveoli attached)
ii.
These are direct or indirect branches of the aorta
Abdomen (slide 28, 26:00)
a. Major artery is abdominal portion of the aorta
b. Classification of branches
i.
Paired vs unpaired
ii.
Parietal (outer) vs visceral (inner/gut)
c. Paired Parietal branches
i.
Inferior phrenic artery: supply the diaphragm (roof of the abdominal cavity)
ii.
4 pairs of lumbar artery that comes off segmentally from the aorta: supply the posterior
wall of the abdomen
iii.
parietal because supply the outer wall of the abdomen
d. Unpaired parietal branches
i.
Median sacral: run down into the pelvis
e. Paired visceral branches (goes to the organs that lies on the posterior abdominal wall/or there at one
time)
i.
Renal arteries going to the kidneys
ii.
Middle suprarenal artery that goes to the suprarenal gland (endocrine gland)
1.
In addition to the middle suprarenal a., each suprarenal gland(endocrine gland)
receives numerous superior suprarenal artery and one or more inferior
suprarenal artery (not direct branches of aorta but help supply)
2.
A rich blood supply is characteristic of endocrine glands
iii.
Gonadal artery: ovarian or testicular arteries
1.
Gonads originate (embryonically) from upper posterior abdominal wall
a. Descend during development and drag blood and nerves with them gonadal
artery comes from the aorta way up high then descend to the pelvis to supply
the ovaries or scrotum for testes
iv.
aorta divides at L4 vertebral level to common iliac artery
1.
further divide to external and internal iliac
f. Unpaired Visceral Branches (slide 29, 28:30)
i.
Come off front of the aorta and goes to the GI tract
1.
Celiac trunk
2.
Superior mesenteric artery
3.
Inferior mesenteric artery
4.
Each supply a specific gut tube originated from embryonic development (foregut,
midgut, hindgut) respectively
Pelvis and Perineum (slide 31, 30:00)
a. Principle artery is internal iliac artery
i.
One of the branches from the common iliac
ii.
Numerous branches
iii.
In anatomy arteries classified where they are going not where they branch from (Internal
Iliac Artery is considered the most variable system in body)
iv.
branches in male and female are very similar
v.
some of the branches supply pelvic viscera
1.
superior vesical to the bladder
2.
middle rectal to the rectum
3.
inferior vesical artery (male) that goes to the prostate gland and seminal vesicle
4.
in female no inferior vesical artery but have vaginal artery to vagina and some
part of the urinary bladder
MS-1 FUND 1: 11:10-12:00
Wednesday, September 10, 2014
Dr. Zehren
Introduction to the Cardiovascular system
Transcriber: Jinwoo Hur
Editor: Victoria Underwood
Page 5 of 7
Abbreviations: GI=gastrointestinal L=lumbar
vi.
XIII.
XIV.
XV.
XVI.
branches that goes to the buttocks or gluteal region
1.
superior and inferior gluteal arteries
vii.
obturator artery leaves the pelvis and goes to lower limb
viii.
internal pudendal artery supplies perineum (anal canal region, external genitalia,
perineum)
ix.
branches goes to many different places so name for where they go to…
lower limb (slide 33, 32:15)
a. major artery is femoral artery
i.
external iliac artery changes its name as it passes the thigh through the inguinal ligament
and becomes the femoral artery
1.
profunda femoris branch (deep artery of the thigh) branch off the femoral artery
a.
has perforating branches supplying back of the thigh (hamstrings)
b.
medial and lateral circumflex artery branches off the profunda
i.
surround neck of the femur (anastomose with each other)
ii.
supply head and neck of femur especially the medial
iii.
Important in old people with osteoporosis  break head/neck of
the femur get torn avascular necrosis  need hip replaced
2.
Lower down the leg femoral artery becomes popliteal artery
Venous system
a. Dural venous sinuses (slide 36, 34:15)
i.
Embedded in the dura mater (outer most covering of brain; Connective tissue)
1.
Dura protects the brain and help supports the brain inside the cranial cavity
ii.
Drain the blood from the dura, brain and the bone of the skull
1.
Blood gets into the sinuses and ultimately, the blood in the sinuses drain into the
base of the skull through the jugular foremanLeaves the skull and becomes the
internal jugular vein
iii.
Dural sinuses communicate (some) with veins outside the skull
1.
Point of communication are called Emissary vein
a.
Valveless (blood can flow in either direction)-> dangerous if infected
because infection can spread via the emissary vein into the sinuses
resulting in meningitis
b.
Blockage of dural sinuses  alternate pathway for blood to escape the
skull
c.
Found throughout little opening in the skull
Internal jugular vein (slide 37, 36:30)
a. Chief vein of the head/neck
i.
Most of the venous blood from cranial cavity drain out at the jugular foremen where the
IJV begins and descends down the neck
b. At the root of the neck, IJV will end by uniting with the subclavian vein right/left brachiocephalic vein
i.
Subclavian drains the upper limb and the IJV drains the head and neck (brachial)
ii.
Left and right brachiocephalic vein unite to make the superior vena cava which goes back
the right atrium of the heart
iii.
Numerous other veins that drain into the IJV as it descend (name base on where it drain)
Upper Limb (slide 39, 38:00)
a. Note: Veins in the cubital fossa. They superficial vein that are imbedded in the superficial fascia are
used for venipuncture (administering drugs/taking sample of blood)
i.
Vein on the lateral side of the fossa called the cephalic vein and on the medial side called
the basilica vein. In between the two (connective them) that is oblique vein called the
median cubital vein
ii.
When cephalic or basilica veins are puncture, runs the risk of piercing/damaging through
the lateral and median cutaneous nerve of the forearm  wouldn’t cause motor problem
but will cause a lot of pain radiating down the radial/medial side of the forearm
MS-1 FUND 1: 11:10-12:00
Wednesday, September 10, 2014
Dr. Zehren
Introduction to the Cardiovascular system
Transcriber: Jinwoo Hur
Editor: Victoria Underwood
Page 6 of 7
Abbreviations: GI=gastrointestinal L=lumbar
iii.
XVII.
XVIII.
XIX.
If you go for medial cubital vein, danger is piercing too deep and damaging brachial
artery or median nervemore serious such as hemorrhage. Median nerve damage is
more serious because it is the sensory and motor in forearm and hand
iv.
Only thing separating the median cubital vein from underlining artery and nerve is the
bicipital aponeurosis (deep fascia)example how deep fascia protect underlining
structure
Thorax (slide 41, 39:45)
a. 4 pulmonary veins (valveless) 2 from each lung draining oxygenated blood back to the left atrium
Abdomen (slide 43, 40:00)
a. Chief vein is the Inferior vena cava (widest vein in the body)
i.
Starts at L 5 (below bifurcation of aorta)
ii.
Formed by the junction of 2 common iliac veins
iii.
Ascend on the posterior abdominal wall (right of the aorta), pierce diaphragm and drain
directly into the right atrium
iv.
Valveless (except when it enters the heart when it has a rudimentary value)
v.
Tributaries of the vena cava some correspond to the branches of the aorta: Inferior
phrenic vein, renal vein, veins that drains the viscera (renal vein that drain the kidney,
gonadal vein draining the ovaries/testes[right gonadal vein is a direct tributary into the
vena cava but the left gonadal vein is a tributary into the left renalsome asymmetry];
right suprarenal vein is direct tributary to vena cava and the left suprarenal vein is a
tributary to the left renal vein)goes back to the development of the vein, how some
veins persist in development and how others drops out creating the asymmetry
vi.
Venous system in general you have left to right shunt of venous blood(right side of the
heart is the venous side). Blood on the left side has to shunt to the right side  The left
renal is longer than right renal vein that crosses aorta to enter the vena cava. Common
iliac is longer than the right and shunts blood to the right
b. Hepatic portal vein (slide 44, 43:00)
i.
Drains the GI tract
ii.
Portal veins mean it will start at the capillaries and ends in another capillary before it goes
back to the heart
1.
Example: Vein that begins in capillaries at the GI tract and ends at the capillaries
in the liverbreak up to capillary like structurethen return to the vena cava by
hepatic vein
iii.
All nutrients except fat is absorbed in the tributaries in the hepatic portal vein then goes to
the liver for metabolism
iv.
Note the hepatic portal vein carrying blood to the liver sinusoids. Blood is then recollected
by several hepatic veins which drain liver into the vena cavaheart
Portal vein anastomoses (slide 45, 43:45)
a. Some of the tributaries of the portal vein anastomose with tributaries of either the superior vena cava
or the inferior vena cava. These are termed portacaval (portal-systemic) anastomoses
b. Location
i.
lower esophagus
ii.
umbilicus
iii.
wall of rectum
iv.
postural abdominal wall
c. bypass obstruction of the blood flow and go back to vena cava
d. portal system is entirely valveless
i.
Example: liver damage -> blow flow through liver is obstructed, it’ll back up in the hepatic
vein and all of its tributaries, and will attempt to go back to inferior and superior vena
cava through anastomoses
1.
problem is these anastomic vessels are small and become engorged with blood.
If they rupture you can get severe bleeding.
a. Example: at the esophagus it can engorge and rupture (esophageal
varices) -> bleed to death
MS-1 FUND 1: 11:10-12:00
Wednesday, September 10, 2014
Dr. Zehren
Introduction to the Cardiovascular system
Transcriber: Jinwoo Hur
Editor: Victoria Underwood
Page 7 of 7
Abbreviations: GI=gastrointestinal L=lumbar
b. Example: in umbilicus, the veins on the abdominal walls becomes
distended during hepatic portal vein obstruction -> caput medusa (slide 46,
45:45)
ARS at 46.31
XX.
Veins of pelvis &perineum (slide 49, 47:30)
a. main vein is the internal iliac vein
b. tributary corresponds with the branches of the internal iliac artery
XXI.
Superficial vein of lower the limb (slide 51-52, 47:45)
a. greater saphenous vein:
i.
start medial of ankle -> groin region -> goes to deep vein to empty at femoral vein
ii.
used frequently for coronary artery bypass operation
b. lesser saphenous vein: later side of ankle -> back of the calf -> popliteal vein
c. used to drain blood from superficial structures
d. connects with deep vein using perforating veins
i.
has valves to make blood flow only from superficial to deep (muscularvenous pump)
1.
Valves becomes incompetent ->blood back flow -> varicose veins -> can
develop blood clots
Student Questions – no student questions
<END OF LECTURE 50:00>