Download THE CIRCULATORY SYSTEM

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
Great cardiac vein
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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
1. Subclavian artery
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.
Terms for the day:
Dysmenorrhea, cachexia, thoracocenthesis, antiemetic, bruit, Cathartic, Arborize
Melena – passage of dark colored, tarry stools
Carminative – An agent that relieves flatulence
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Admexa – parts accessory to the main organ or structure
2. Thyrocervical trunk
supplies thyroid gland, trachea and larynx
inferior thyroid a.
suprascapular a.
transverse cervical a.
3. Costocervical trunk
supplies upper intercostal m., spinal cord, meninges, posterior neck muscles.
superior intercostal a.
deep cervical a.
Internal thoracic a. is the last branch off, runs inside the chest wall along the posterior surface of the anterior wall
To determine what artery you are looking at, look at 3 things:
1. location
2. what does it supply?
3. where does it come from?
Axillary artery ( once the subclavian artery passes the first rib it becomes the axillary artery )
•
•
•
•
•
N 398
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 (once the axillary artery drops inferior to the teres major m.)
profunda a.
superior ulnar collateral a.
inferior ulnar collateral a.
•
Radial artery – ultimate termination artery – pulse/BP
joins ulnar to form the superficial palmar arch
swings posteriorly, can be palpated in anatomic snuff box
•
Ulnar artery – ultimate termination artery
superficial palmar arch
Branches of the Thoracic Portion of the Aorta
1. pericardial arteries
2. bronchial arteries
3. esophageal arteries
4. posterior intercostal arteries – run in intercostal space along with vein and nerve
5. superior phrenic arteries
Branches of the Abdominal Portion of the Aorta
The descending thoracic aorta become the abdominal aorta when in passes through the hiatus in the diaphragm
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•
•
Inferior phrenic a.
Celiac Trunk (for foregut derivatives: stomach, spleen, liver) – comes off anteriorly
left gastric a.
common hepatic a.
splenic a.
Superior mesenteric a.(for midgut derivatives: pancreas and duodenum)
5 basic branches ( there are hundreds of branches off here)
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1. inferior pancreaticoduodenal a. – pancreas and duodenum
2. jejunal and ileal aa.
3. Ileocolic a. – Ileocecal valve
4. right colic a. – ascending colon
5. middle colic a.- transverse colon
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•
•
•
•
Inferior mesenteric a. (for hind gut derivatives)
left colic a. – descending colon
sigmoid a. – sigmoid colon
superior rectal a. – superior aspect of rectum
N 286
Renal arteries
20% of cardiac output through here
suprarenal a.
Gonadal arteries
testicular a. - male
ovarian a. - female
N 287
Lumbar arteries
Middle sacral a.
Arteries of the Pelvis and Lower Extremity
Common iliac arteries
N 477
External iliac a. turns into the femoral artery once it passes the inguinal ligament
 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.
N 338
 internal pudendal a. and perineal a. – this can be occluded in long distance bikers and cause impotence.
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
Miscellaneous Veins
1. Medial cubital vein cubital fossa
2. Great saphenous vein – medial aspect of thigh and leg
3. Azygos vein
N 97
N 448
N 508
Normally, circulation goes: heart  artery  capillary  vein  heart
Portal systems are the exception to the rule. Here the blood flow is as follows:
heart  artery  capillary  vein  capillary  vein heart
1. Hepatic portal vein
superior mesenteric vein
}
splenic vein
} combine to form the portal vein
liver drained by the hepatic vein which empties into the inferior vena cava
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2. Hypophyseal portal system
N 141
Located between the hypohysis and the pituitary gland, its main function is to transport hormones from the
hypothalamus to the pituitary gland.
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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