THE CIRCULATORY SYSTEM
4-6-99
Terms of the day:
Chondromalcia, febrile /pyrexia, Autopsy, Carcinogen, Tactile, Exopthalmus, Antagonist, Hyptonia, Anaphylaxis,
Ambulate
Ramus – a branch or primary divisions of a nerve or blood vessel. One of the primary divisions of a cerebral sulcus. A
part of an
irregularly shaped bone (less slender than a “process”) which forms an angle with the main
body.
Prolapse – to sink down, a sinking of an organ or other part, especially its appearance at a natural or artificial orifice.
Palsy – often connotes partial paralysis or paresis.
Somnolence – a condition of semiconsciousness approaching coma, sleepiness; an inclination to sleep.
Ptarmic – sternutatory, causing to sneeze.
Entropion – the infolding of the margin of an eyelid, inversion or turning inward of a part.
Paresis – Partial or incomplete paralysis.
Anamnesis – The act of remembering. The medical or developmental history of a patient.
Anisosocoria – unequal pupil size
Introduction
Functions of the circulatory system
1. Transportation
 RBC’s carry O2 and CO2
 nutrients
 waste products
 hormones
2. Protection
 WBC’s, immune cells, antibodies
Major components of the circulatory system
1. Blood
2. Blood vessels
3. Heart
The Heart
p. 529-538
Location and General Description
 Hollow, 4 chambered muscle
 2/3 of the heart are located to the left of the midline
 the base of the heart is just inferior to the angle of Louis
 Apex is distal to the base, between 5th and 6th ICS( intercostal space )
 Mediastinum - median portion of the thoracic cavity, contains all thoracic viscera except the lungs.
 Pericardium – surrounds the heart
1. fibrous pericardium – thick sac that does not expand - primary reason for air bags
2. serous pericardium
a. parietal serous pericardium
b. visceral serous pericardium - epicardium
pericardial cavity – between the parietal and visceral pericardium
N 200
Heart wall
1. epicardium – visceral serous epicardium
2. myocardium
3. endocardium
Heart Chambers and Valves
N 212
 4 chambers, 2 upper atria (receive blood from body and lungs) and 2 lower ventricles (pumping chambers to body
and lungs). Atria contract simultaneously, and the ventricles contract simultaneously.
 interatrial septum
 interventricular septum
 atrial walls and much thinner than ventricular walls, and the left ventricle is much thicker than the right
 atrioventricular valves - right and left
 semilunar valves - aortic and pulmonary
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Circulation of blood through the heart
Blood from the body  right atrium  right AV valve  right ventricle  semilunar valve pulmonary trunk  lungs
 pulmonary veins  left atrium  left AV valve left ventricle semilunar valve  aorta  body
Right Atrium
 Vessels entering the right atrium
1. superior vena cava
2. inferior vena cava
3. coronary sinus
 Pectinate muscles – walls of atria
 Fossa ovale – adult structure of the foramen ovale
N 208
Right Ventricle
 Right atrioventricular valve - tricuspid valve
 Chordae tendineae – prevent inversion of the valves into the atrium, act like guide wires
 3 Papillary muscles – anchor the chordae tendinae
 Trabeculae carneae – correspond to the pectinate muscles of the atria
 Conus arteriosus – infundibulum, funnels blood toward the p. trunk
 Pulmonary valve - pulmonary semilunar valve
 Pulmonary trunk – dilated by blood  recoils elastic fibers, valve closes
Left Atrium
Pulmonary veins - 4
N 209
Left Ventricle
 Left atrioventricular valve - bicuspid valve or mitral valve
 Aortic valve - aortic semilunar valve
 Aorta
Conduction System of the Heart
N 213
Atria contract from base to apex, ventricles contract from apex to base.
Impulses in the heart are carried by conductive cells that have very leaky membranes to Na. Na/K is constantly selfdepolarizing the heart. The Vagus nerve makes the membranes less permeable to Na ( i.e.  slows HR), and Norepi
makes the membranes more permeable to Na ( i.e. increases HR)
 Sinoatrial node (70-80 BPM)  SA node - internodal fibers  carry impulses down to the ventricles
 Atrioventricular node or AV node – delays the impulse so that the atria contract fully, then the impulse is carried to
the …
 Atrioventricular Bundle - Bundle of His which in turn branches into L and R and passes the impulse along to the …
 Conduction Myofibers - Purkinje Fibers
Systole - contraction of the heart, especially the ventricles
Diastole - postsystolic dilation of the heart, in which the chambers fill with blood.
Contract  empty  relax fill
Heart sounds
first heart sound - Lub - closing of the AV valves, during ventricular systole
second heart sound - dup - closing of the semilunar valves, during ventricular diastole
N 210
The Coronary Vessels p. 534-535
Blood flows through the coronary vessels during ventricular diastole. The aortic sinus prevents the aortic valves from
sticking – it is where the coronary arteries go off.
1. Right Coronary Artery
Right marginal artery
Posterior Interventricular artery – goes down the sulcus
2. Left Coronary Artery – divides almost immediately
Anterior Interventricular artery
Circumflex artery – goes to the dorsum
3. Coronary Veins
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Great cardiac vein
Middle cardiac vein – psterior interventricular septum
Coronary sinus  into right atrium
The Blood Vessels p. 538-562
Blood Pressure
N 204
PR = peripheral resistance – the resistance on blood by blood vessels, affected by:
1. diameter of the vessel – increased diameter  less resistance, decreased diameter increased resistance
2. length of the vessel – the longer the vessel, the higher the resistance ( each pound of fat adds 10 miles of
capillaries for blood to travel)
3. viscosity – thickness of the blood ( essential high BP )
BP = CO x PR,
CO = cardiac output
CO = HR x SV
systolic pressure – pressure of ejection from ventricle
diastolic pressure – vascular tone of the blood vessels - controlled by ANS
The Arteries
Aortic Arch – 3 branches off here ( TEST)
1. Brachiocephalic Trunk
a. Right common carotid artery
b. Right subclavian
2. Left common carotid artery
3. Left subclavian
N 225
Blood Supply to the Neck and Head
N 130
1. Common carotid artery – bifurcates at the angle of the jaw to deliver 50% of blood going to the brain
A. Internal carotid artery
1. ophthalmic artery
2. posterior communicating artery
3. anterior cerebral artery
4. middle cerebral artery
B. External carotid artery – supplies the superficial face ( the detail of this vessel just FYI for now)
1. superior thyroid a.
2. ascending pharyngeal a.
3. lingual a.
4. facial a.
5. maxillary a.
6. superficial temporal a.
7. posterior auricular a.
8. occipital a.
Arteries to the Shoulder and Upper Extremity
Subclavian artery
1. Vertebral artery – is the first branch off, ascending in the transverse foramen of superior C6 continues on
posteriorly over the posterior arch of the atlas towards the foramen magnum to join at the anterior surface of the
medulla to form the…
 basilar artery which splits to join the posterior communicating artery
 Circle of Willis
N 133
1. posterior cerebral artery
2. posterior communicating artery
3. internal carotid artery
The anterior communicating artery joins the anterior cerebrals.
The anterior communicating artery sometimes has a defect in its wall and develops an aneurism. Incidence is higher in
females, called Berry aneurism ( Berry very bad). First sign is sudden blindness due to pressure on the optic chiasma.
Thyrocervical trunk
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 thyroid gland, trachea and larynx
inferior thyroid a.
suprascapular a.
transverse cervical a.
Costocervical trunk
 upper intercostal m., Spinal cord, meninges, posterior neck muscles.
– superior intercostal a.
– deep cervical a.
 Internal thoracic a.
Axillary artery (inferior to first rib)
 superior thoracic a.
 thoracoacromial a.
– acromial a.
– deltoid a.
– pectoral a.
– clavicular a.
 lateral thoracic a.
 subscapular a.
– circumflex scapular a.
– thoracodorsal a.
 anterior and posterior circumflex humeral aa.
 Brachial artery (inferior to the teres major m.)
– profunda a.
– superior ulnar collateral a.
– inferior ulnar collateral a.
 Radial artery
– joins ulnar to form the superficial palmar arch
 Ulnar artery
– superficial palmar arch

Branches of the Thoracic Portion of the Aorta
4. pericardial arteries
5. bronchial arteries
6. esophageal arteries
7. posterior intercostal arteries
8. superior phrenic arteries
Branches of the Abdominal Portion of the Aorta
 Inferior phrenic a.
 Celiac Trunk (for foregut derivatives)
– left gastric a.
– common hepatic a.
– splenic a.
 Superior mesenteric a.(for midgut derivatives)
– inferior pancreaticoduodenal a.
– jejunal and ileal aa.
– Ileocolic a.
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– right colic a.
– middle colic a.
Branches of the Abdominal Aorta, con’t.
 Inferior mesenteric a. (for hind gut derivatives)
– left colic a.
– sigmoid a.
– superior rectal a.
 Renal arteries
– suprarenal a.
 Gonadal arteries
– testicular a. - male
– ovarian a. - female
 Lumbar arteries
 Middle sacral a.
Arteries of the Pelvis and Lower Extremity
 Common iliac arteries
– External iliac a.
 femoral a.
– superficial circumflex iliac a.
– superficial epigastric a.
– superficial external pudendal a.
– deep external pudendal a.
– profunda femoris a. - medial and lateral femoral circumflex aa.
– Popliteal a.
– Anterior Tibial a. - dorsal pedal a and arcuate a.
– Posterior Tibial a. - peroneal a. and medial and lateral plantar aa.
– Internal iliac a.
 internal pudendal a. and perineal a.
The Veins
 Veins that Drain the Brain
– Dural Sinuses







superior sagittal sinus
inferior sagittal sinus
straight sinus
confluence of sinuses
transverse sinus
sigmoid sinus
internal jugular vein
Veins, cont.

Miscellaneous Veins
9. Medial cubital vein
10. Great saphenous vein
11. Azygos vein
Portal systems
 Hepatic portal vein
– superior mesenteric vein
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– splenic vein
– liver drained by the hepatic vein
 Hypophyseal portal system
–
–
–
–
–
superior hypophyseal a.
primary plexus
long and short hypophyseal portal veins - to adenohypophysis
secondary plexus
efferent hypophyseal veins to cavernous sinus
Fetal circulation - p. 560-562
The End
of
Systemic Anatomy
Lecture Material
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