Cardiac Anatomy Pt. II Flashcards by J L

The functional segmentation of each lung is reflected in the branching of the left and right ____ which arise at the bifurcation of the PULMONARY TRUNK

pulmonary arteries

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With the ____ removed, the bifurcation of the pulmonary trunk may be visualized
more clearly

pericardial sac

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Each PULMONARY ARTERY enters the lung at the ____ on the ____ SURFACE of the organ

hilum or root

mediastinal

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Pulmonary arterioles
are continuous with a
\_\_\_\_
in intimate contact with
the air sacs (alveoli) of
the lung, which are in
turn drained by tributaries of the \_\_\_\_

capillary network

pulmonary veins

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Paired superior and inferior Pulmonary Veins return oxygenated blood to the ____

left atrium

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The LEFT ATRIUM

• Receives the drainage
of the ____
• Has a smooth relatively featureless wall, marked only by the ____
• Delivers blood to the left ventricle through the left atrioventricular orifice,
guarded by the ____

pulmonary veins
fossa ovalis
bicuspid (mitral) valve

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The LEFT VENTRICLE
• Has the \_\_\_\_ wall of all the chambers
• Has prominent \_\_\_\_
• Normally features two
robust \_\_\_\_ anchoring the cusps of the \_\_\_\_ valve

Significantly, the larger ____ cusp of the valve is immediately adjacent to, and continuous with, the wall of the aorta

thickest
trabeculae carnae
papillary muscles
bicuspid (mitral) valve
anterior

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Bicuspid (mitral) valve in systole

as the blood flowing
through the atrio-
ventricular orifice
makes a sharp turn
and flows into the \_\_\_\_ during ventricular systole

ascending aorta

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The openings (ostia) of the left and right coronary arteries are associated with the ____ adjacent to the left and right cusps of the aortic ____ valve

sinuses of valsalva

semilunar

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Both the AORTIC and PULMONARY valves are ____, with cusps opening passively and closing passively… … as the aortic valve closes, blood in the aortic sinuses fills the ____

Diastole - pressure drop > blood falls back to LV, and moves cusps away form circumference of vessel > aortic pockets > sinuses of valselva

semilunar

coronary arteries

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ATRIOVENTRICULAR VALVES (with atria removed)

IN VENTRICULAR DIASTOLE…
The ventricular wall
is ____, the valves are open and blood
flows from the atria to the ____

THEN…

As the ventricles fill, the thin, elastic cusps rise toward the ____, the cusps appose and the valves are ____ passively

THEN…

IN VENTRICULAR SYSTOLE…
contraction of the myocardium raises the ventricular pressure & tightens the ____ to keep the valves ____

relaxed
ventricles
atrio-ventricular orifices
closed
chordae
closed

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SEMILUNAR VALVES

IN VENTRICULAR SYSTOLE…
Contraction of the ventricle pumps blood toward the ____ and ascending aorta, separating the thin, elastic semilunar cusps, ____ the valves

THEN…

IN VENTRICULAR DIASTOLE…
As the ventricles relax, pressure descreases in the aorta and pulmonary trunk, blood falls back toward the ____ and… the cusps are forced away from the vessel walls and into apposition, ____ the valves.

pulmonary trunk
opening

heart
closing

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Valvular Heart Disease
• Valvular insufficiency results from a poorly functioning (incompetent) valve that cannot ____
completely, producing regurgitation

Valvular stenosis is the pathological narrowing of an ____ as the result of the inability of the valve to open completely, leading to back-up and increased upstream risk of ____
Both ____ and ____ cause turbulence in blood flow through the valve which produces vibrations audible as murmurs
Acquired valvular disease may result from ____ and subsequent ____ of the valves produces scarring which thickens and rigidifies the elastic cusps

close
orifice
clot formation

stenosis
regurgitation

bacterial infection
inflammation

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Common scenarios:

– Rheumatic heart disease triggered by an autoimmune reaction to infection with ____ …may lead to ____ or ____ valve damage
– Bacterial endocarditis – results from spread of bacteria entering the bloodstream either as the result of poor ____ or during ____, particularly in individuals with pre-existing cardiac conditions and other specific risk factors.

group A streptococci
mitral
aortic

oral hygiene
dental procedures

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Auscultation of the valves requires placement of the stethoscope not directly OVER the surface projections of the valves but rather ____ from them

To position ourselves, in normal person:
• Heart lies in thorax with ____ to left of mid-sagittial plane and ____ to right of mid-sagittal plane
• Apex of heart in mid-clavicular line of 5th intercostal space
We have good sense of where 4 valves project onto anterior thoracic wall, however we put bell of stethoscope just downstream location of valve to listen to fluid that has just passed through it

downstream
2/3
1/3

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AORTIC VALVE
Parasternally in ____ intercostal space

TRICUSPID VALE
Parasternally in ____ intercostal space

PULMONARY VALVE
Parasternally in ____ intercostal space

MITRAL VALVE
____ intercostal space ca. ____ lateral to the sternum

right 2nd
left 4th or 5th
left 2nd
left 5th
6 cm

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Cardiac nerves derived from both divisions of the ____ commingle in the ____, travel along the ____, and
serve to modify the rate and strength of the heart beat…

… but they neither initiate nor maintain it!

ANS
cardiac plexus
coronary plexus

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The atria and ventricle contract in normal sequence before nerves contact the embryonic heart… and the same is true when the ____ is severed from the nervous connections.

transplanted heart

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The CONDUCTION SYSTEM

SA NODE
“THE ____ OF THE HEART”

Initiates impulses producing a contractile wave through the myocardium

The contraction signal from the SA node spreads
through the walls of the ____ to the AV node…

Located near the top of the ____, along the anterior lip of the ____ orifice

pacemaker
right atrium
crista terminalis
SVC

Though these bundles are distinct anatomically, impulses from the SA node spread ____ through the atrial myocardium

uniformly

AV NODE
Located in
the ____, it distributes the signal to the ventricles through the ____

interatrial septum
AV bundle (of His)

The ____ blocks the direct spread of electrical impulses from atrial to ventricular myocardium.

Activation of the ventricles is normally achieved through the ____ only

non-conductive fibrous skeleton

AV bundle

AV BUNDLE
Gives rise to left and right bundle branches which descend along the muscular portion of the ____

Sub-endocardial branches (Purkinje fibers) extend to the ____ and walls of the ____

interventricular septum
apex
ventricles

AV bundle block or bundle branch block
may result from local damage due to ____

AV bundle block (aka heart block) disassociates atrial and ventricular contraction, leading to slow and often irregular ____ contraction

myocardial infarction

ventricular

Papillary muscles receive Purkinje fibers guaranteeing coordination of ventricular contraction with the tightening of the ____

chordae tendinae

Electrophysiology of the heart • The usual rhythm of heartbeats, established by the SA node, is called normal sinus rhythm. The term ____ refers to abnormal rhythm resulting from a conduction system defect. Arrhythmias are categorized by their ____, rhythm, and origination of the problem: – Bradycardia refers to a slow heart rate (below ____ beats per minute) – Tachycardia refers to a rapid heart rate (over ____ beats per minute) – ____ refers to rapid, irregular and uncoordinated heart beats. • Atrial fibrillation may lead to blood ____, clot formation and ____ • Ventricular fibrillation, the most ____; produces abnormal heart cycles that cause the heart to twitch rapidly and irregularly while failing to pump the blood • Arrhythmias may be caused by factors that stimulate the heart such as ____, caffeine, ____, nicotine & cocaine • Arrhythmias may also be caused by ____ defects, coronary artery disease, ____, hypertension, defective heart valves, ____ disease, hyperthyroidism and ____ deficiency. • Abnormal electrical signals from the SA node can be corrected by placement of a ____

``` arrhythmia (dysrhythmia) speed 50 100 fibrillation stagnation stroke dangerous ``` stress alcohol congineital myocardial infartion rheumatic heart potassium pacemaker

PACEMAKER Placed deep to skin underlying ____ musculature, and the leads extend to heart via the ____ system (cephalic vein, ____; and then deeper veins until reaching ____)

pectoral venous superficial vena cava

The SA NODE is normally (>65%) supplied by a branch of the ____ The AV NODE may be supplied by a branhc of either the right or left ____ arising from the ____

RCA coronary arteries CRUX

The Autonomic Nervous System exerts extrinsic influence on the heart Cardiac plexus receives inputs from both divisions of the ____ In healthy heart with normal resting heart rate from low 50's to around 80, there will be some extrinsic influences working on heart. Here are the extrinsic neural influences, which don't reach heart until it begins to contract on its own during development. So where are these neural influences found? Two places: 1. Aortic arch -____ 2. Bifurcation of trachea - ____ Both plexuses receive inputs form both divisions of autonomic nervous system (sympathetic and parasympathetic)

ANS superficial cardiac plexus deep cardiac plexus

Sympathetic inputs originate in ____ spinal cord segments...… and synapse in ganglia along the ____ Parasympathetic inputs are of ____ origin...… and synapse in ____ and ____

upper thoracic coronary plexus vagal cervical upper thoracic chain ganglia

Parasympathetic inputs to cardiac plexus Vagal afferents convey impulses from ____ in and outside the walls of the great vessels near the heart • ____ heart rate • ____ the force of myocardial contraction • ____ coronary arteries

baro- and chemoreceptors decrease decrease vasoconstrict

Sympathetic inputs to cardiac plexus * ____ heart rate * ____ the force of myocardial contraction * ____ coronary arteries

increase increase vasodilate

Sympathetic cardiac nerves also convey ____ fibers from the heart back to cervical and upper thoracic spinal nerves and their dorsal root ganglia... ____ fibers may stimulate somatic afferents in the ____ and dorsal horn of spinal grey, providing the basis of "____"

visceral afferent GVA dorsal root referred cardiac pain

A lack of oxygen to cardiac muscle (myocardial ischemia) may produce ____ ...This explains the distribution of the “REFERRED CARDIAC PAIN” from ANGINA PECTORIS to the substernal and pectoral regions, the ____ and the ____

cardiac pain shoulder medial upper limb

FETAL CIRCULATION Umbilical Vein • Will convey ____ blood from placental membranes into fetal body and then a small amount of blood towards the ____. • Most of the newly oxygenated blood will bypass the liver completely into the shunt called the ____ Ductus Venous • Will introduce newly oxygenated blood into ____ just below diaphragm, and then will enter right atrium through IVC • Now in right atrium we see blood flow from two major vessels: IVC and SVC-they are not ____ but rather just flow past each other (____) • Blood from IVC will be shunted through ____ (not the one from the skull!) Foramen Ovale • Blood now goes through foramen ovale and is shunted into left atrium, thus bypassing a unestablished ____ circulation • As we follow blood from left atrium into left ventricle, we see that blood ejected out through the aorta • We see as we reach the underside of aortic arch, another shunt called ____. Ductus Arteriosus • This brings us back to right atrium-there are different fates as we said before of blood coming from SVC vs. IVC and here the blood from SVC goes from right atrium to ____ through pulmonary trunk into the ductus arteriosus • BUT there is no pulmonary circulatioon yet, so this blood will go through other blood into aortic arch, reaching ____ ◦ This mixed blood descends down towards pelvic region where we see paired ____ - will be returning used deoxygenated blood back to the placenta!

oxygenated liver ductus venous IVC mixed laminar flow foramen ovale pulmonary ductus arteriosus right ventricle descending aorta umbilical arteries

Ductus arteriosus | is usually functionally closed by ____ hours after birth.

10-15

____ accounts for 10% of congenital heart lesions * Untreated, may lead to pulmonary ____ * and heart failure * Can be treated with ____, catheterization or ____ surgery

patent ductus arteriosus hypertension medication open-heart

Congenital Defects • Most defects are atrial or ventricular ____ defects and can result in blood flowing from chamber of higher pressure to the chamber with ____ pressure * Atrial septal defect: usually marked by failure of the ____ to close completely: results in shunting of blood between atria in either ____; often ____. * Ventricular septal defects: incomplete ____ of the ventricles, produces flow of blood from left ventricle to right ventricle. May lead to ____ if nor corrected surgically

septal lower foramen ovale direction asymptomatic partitioning heart failure

VSD – the most ____ congenital cardiac anomaly • Congestive heart failure can develop with significant left-to-right shunting and increased volume load to the ____ vasculature

common | pulmonary

ASD – 10-15% of congenital cardiac anomalies ASD’s often coexist with other ____. The degree of hemodynamic disturbance is related to the ____ of the defect and the ____ of blood flow shunting

anomalies size amount

``` The plane of the ____ divides the thoracic aorta into three separate portions - ____ - ____ - ____ ``` Ligamentum arteriosum (____ nerve wraps around)

``` sternal angle ascending aorta aortic arch descending aorta L recurrent laryngeal ```

The aortic arch arches over the left main ____ and left ____

bronchus | pulmonary artery

____ afferents (CN ____) convey inputs from several clusters of chemoreceptors and baroreceptors located along the ____

vagal X aortic arch

Three large vessels usually arise from the aortic arch in the superior mediastinum - ____ - ____ - ____

left common carotid left subclavian brachiocephalic trunk

The Brachiocephalic Trunk (innominate artery) in turn gives rise to the right ____ and ____ arteries

subclavian | common carotid

- Aortic dissection A tear of the ____ leads to accumulation of blood and separation of intima and media Symptoms may be confused with those of a ____

intia | heart attack