Tag: nerve supply

Heart-arterial supply, nerve supply, veins of heart

Heart-arterial supply, nerve supply, veins of heart


ARTERIAL SUPPLY OF HEART

  • The arterial supply of the heart is provided by the right & left coronary arteries, which arise from the ascending aorta above the aortic valve.

 

RIGHT CORONARY ARTERY

LEFT CORONARY ARTERY

 

  • Branch of anterior aortic sinus of ascending aorta.
  • Runs in the right anterior coronary sulcus (right atrioventricular groove) & then winds round to inferior border to run backards in the right posterior coronary sulcus & reaches the posterior interventricular groove where it ends by anastomosing with left coronary artery.
  • Rt coronary artery (RCA)Diameter less than LCA
  • Larger than right coronary artery.
  • Arises from left posterior aortic sinus of ascending aorta.
  • It enters  the atrioventricular groove & gives anterior interventricular branch.
  • Further continuation of LCA known ascircumflex artery.

    BRANCHES

  • Acute marginal (Right marginal)
  • Posterior interventricular (descending)artery in 85-90% of cases.
  • Right conus (infundibular) artery(sometimes it arises directly from anterio aortic sinus & is called third coronary artery)
  • Nodal branch to SA node (in 65% cases)
  • Atrial, anterior ventricular & posterior ventricular

 

  • Anterior interventricular (descending) artery
  • Circumflex artery
  • Left diagonal
  • Obtuse marginal (left marginal)
  • Left conus artery
  • Atrial branch, anterior ventricular branch & posterior ventricular branch
  • Nodal (in 35%) for SA node.

ARTERIAL            SUPPLY

  • Right atrium & a part of left atrium
  • Most of the right ventricle (except the area adjoining the anterior interventricular groove) & small part of left ventricle adjoining posterior interventricular groove
  • Posterior interventricular septum
  • Whole conducting system (except right bundle branch & a part of left branch of AV bundle).
  • SA Node- (in 65%)

 

  • Most of left atrium
  • Most of the left ventricle
  • Anterior 2/3 of ventricular septum
  • Right bundle branch
  • Left bundle branch
  • SA Node- 35% of cases

 CARDIAC DOMINANCE

  • The artery from which the posterior interventricular artery (posterior descending artery (PDA) arises determines the coronary dominance.
  • RIGHT DOMINANT HEART: In 90% cases, right coronary artery gives posterior interventricular artery.
  • LEFT DOMINANT: in 10% cases, posterior interventricular artery is a branch of circumflex artery.
  • In CODOMINANCE or BALANCED PATTERN, branches of both RCA & LCA run in the posterior interventricular groove.
  • Dominance should not be confused with the amount of tissue supplied: left coronary artery supplies major part of heart, whether right dominance or left dominance.  

INVOLVEMENT OF CORONARY CIRCULATION IN THROMBOSIS

1. Left anterior descending artery (anterior interventricular) artery is most commonly involved in thromboticocclusion.

  • This results in infarction of anterior wall of left ventricle, apex of heart & anterior 2/3 of ventricular septum.

2. Right coronary artery or its posterior interventricular branch is involved 2nd most commonly.

  • This results in infarction of inferior/posterior wall of left & right ventricle, posterior 1/3 of ventricular septum.

3. 3rd most commonly involved vessel is circumflex coronary artery (branch of LCA).

  • This results in infarction of lateral wall of left ventricle except apex.

4. Left main coronary artery, diagonal branches of LAD artery & marginal branches of circumflex artery are uncommon to be involved.

 BLOOD SUPPLY OF CONDUCTING SYSTEM OF THE HEART: 

  • SA NODE: right coronary artery (nodal branch) (65%), left coronary artery (35%).
  • AV NODE, AV BUNDLE & BUNDLE OF HIS: right coronary artery.
  • RIGHT BUNDLE BRANCH: left coronary artery
  • LEFT BUNDLE BRANCH: mostly by left coronary artery, few parts by right coronary artery.

VEINS OF THE HEART

  1. Coronary Sinus:
  • Largest vein of the heart situated in the left Posterior coronary sulcus.
  • Ends by opening into the posterior wall of the right atrium b/w IVC opening & AV orifice.
  • Orifice of coronary sinus is guarded by thebesian valve while IVC orifice is guarded by rudimentary Eustachian valve (SVC orifice has no valve).
  • Coronary sinus develops from body & left horn of sinus venosus.

The tributaries are:

  1. Great cardiac.V (anterior interventricular vein)→ Enters the left end of coronary sinus at its origin,
  2. Middle cardiac V (posterior interventricular vein)  → Joins the middle part of coronary sinus
  3. Small cardiac vein  → Joins the right end of coronary sinus
  4. Posterior vein of left Ventricle → Ends in middle of coronary sinus
  5. Oblique Vein of left atrium of Marshalls → Terminates in left end of coronary sinus (Develops from left common cardinal Vein (duct of curier)

2.  Anterior Cardiac Veins:

  • These veins are 3 or 4 small veins which run parallel to each other on the anterior wall of right ventricle.
  • Opens directly into the right atrium through its anterior wall.

3. Thebesian Veins (Venae Cordis minimi)

  • They are the numerous small veins present in all the four chambers.
  • These drains into right atrium.
  • The venae Cordis minimi are more numerous on right side & least in left ventricle.
→ All the veins mentioned above drain into coronary sinus except anterior cardiac vein, venae cordis minimi & often right marginal vein.
 These three drain directly into right atrium.

NERVE SUPPLY OF HEART

Has both   i) motor  &  ii) sensory components

MOTOR COMPONENT:

  • Motor component includes parasympathetic & sympathetic systems.
  • Parasympathetic fibers reach the heart through vagus & are cardioinhibitory.
  • Sympathetic fibers are derived from T1 to T5 segment of spinal cord & are cardiostimulatory (excitatory).
  • SA node is supplied by right vagus/parasympathetic (inhibitory) and right Sympathetic (excitatory) system.
  • Both parasympathetic & sympathetic nerves form the superficial & deep cardiac plexus, the branches of which run along the coronary arteries to reach the myocardium.

 

 

Superficial cardiac plexus

Deep cardiac plexus

  Location

  • Below the arch of aorta in front of right pulmonary artery
  • In front tracheal bifurcation and behind the arch of aorta

  Components

  • Superior cervical cardiac branch of left sympathetic chain & Inferior cervical cardiac branch of left vagus
  • All the cardiac branches derived from all the cervical & upper thoracic ganglia of the sympathetic chain.
  • Cardiac branches of vagus a RLN except those forming superficial plexus.

 → A small ganglion, the cardiac ganglion of Wrisberg, is occasionally found connected with these nerves at their point of junction.

→ This ganglion , when present, is siyuated immediately beneath the arch of aorta, on right side of ligamentum arteriosum. 

SENSORY COMPONENT:

  • Pain sensation arising due to ischemia is conveyed by afferents which pass through sympathetic cardiac fibers & reach the T1 to T5 cord segments on left side.
  • Since these dorsal root ganglia also receives sensory impulses from the medial side of arm, forearm & upper part of front of vhest, the pain gets referred to these areas through these thoracic splanchnic nerves (T1-T4).
Exam Question
 

RIGHT CORONARY ARTERY

LEFT CORONARY ARTERY

 

  • Branch of anterior aortic sinus of ascending aorta.
  • Runs in the right anterior coronary sulcus (right atrioventricular groove) & then winds round to inferior border to run backards in the right posterior coronary sulcus & reaches the posterior interventricular groove where it ends by anastomosing with left coronary artery.
  • Rt coronary artery (RCA)Diameter less than LCA
  • Larger than right coronary artery.
  • Arises from left posterior aortic sinus of ascending aorta.
  • It enters  the atrioventricular groove & gives anterior interventricular branch.
  • Further continuation of LCA known as circumflex artery.

    BRANCHES

  • Acute marginal (Right marginal)
  • Posterior interventricular (descending) artery in 85-90% of cases.
  • Right conus (infundibular) artery (sometimes it arises directly from anterio aortic sinus & is called third coronary artery)
  • Nodal branch to SA node (in 65% cases)
  • Atrial, anterior ventricular & posterior ventricular

 

  • Anterior interventricular (descending) artery
  • Circumflex artery
  • Left diagonal
  • Obtuse marginal (left marginal)
  • Left conus artery
  • Atrial branch, anterior ventricular branch & posterior ventricular branch
  • Nodal (in 35%) for SA node.

    ARTERIAL            SUPPLY

  • Right atrium & a part of left atrium
  • Most of the right ventricle (except the area adjoining the anterior interventricular groove) & small part of left ventricle adjoining posterior interventricular groove
  • Posterior interventricular septum
  • Whole conducting system (except right bundle branch & a part of left branch of AV bundle).
  • SA Node- (in 65%) 
  • Most of left atrium
  • Most of the left ventricle
  • Anterior 2/3 of ventricular septum
  • Right bundle branch
  • Left bundle branch
  • SA Node- 35% of cases
Don’t Forget to Solve all the previous Year Question asked on Heart-arterial supply, nerve supply, veins of heart

Heart-arterial supply, nerve supply, veins of heart

HEART-ARTERIAL SUPPLY, NERVE SUPPLY, VEINS OF HEART

Q. 1

Anterior cardiac veins open into:

 A

Right atrium

 B

Great cardiac vein

 C

Coronary sinus

 D

Marginal vein

Q. 1

Anterior cardiac veins open into:

 A

Right atrium

 B

Great cardiac vein

 C

Coronary sinus

 D

Marginal vein

Ans. A

Explanation:

Right atrium


Q. 2

In which of the following cardiac structure is middle cardiac vein located?

 A

Anterior AV groove

 B

Posterior AV groove

 C

Anterior interventricular sulcus

 D

Posterior interventricular sulcus

Q. 2

In which of the following cardiac structure is middle cardiac vein located?

 A

Anterior AV groove

 B

Posterior AV groove

 C

Anterior interventricular sulcus

 D

Posterior interventricular sulcus

Ans. D

Explanation:

Posterior interventricular vein or middle cardiac vein runs in the posterior interventricular sulcus and may drain into the right atrium or into the coronary sinus.

Q. 3

The middle cardiac vein is located in the?

 A

Anterior interventricular sulcus.

 B

Posterior interventricular sulcus.

 C

Posterior AV groove.

 D

Anterior AV groove.

Q. 3

The middle cardiac vein is located in the?

 A

Anterior interventricular sulcus.

 B

Posterior interventricular sulcus.

 C

Posterior AV groove.

 D

Anterior AV groove.

Ans. B

Explanation:

The middle cardiac vein commences at the apex of the heart; ascends in the posterior longitudinal sulcus, and ends in the coronary sinus near its right extremity.


Q. 4

Anterior cardiac vein open into ?

 A

Right atrium

 B

Great cardiac vein

 C

Coronary sinus

 D

Marginal vein

Q. 4

Anterior cardiac vein open into ?

 A

Right atrium

 B

Great cardiac vein

 C

Coronary sinus

 D

Marginal vein

Ans. A

Explanation:

The anterior cardiac veins drain the anterior portion of the right ventricle, cross the coronary groove, and empty directly into the right atrium. Anterior cardiac veins do not drain into the coronary sinus.
 Also Know:

The coronary sinus is the largest vein draining the heart muscle and lies in the coronary sulcus. The coronary sinus collects most of the venous return from the great, middle, and small cardiac veins and returns the venous blood to the right atrium. The coronary sinus opening in the right atrium is superior to the septal leaflet of the tricuspid valve.


Q. 5

Branches of R.C.A. (Rt. Coronary artery):

 A

Obtuse marginal

 B

Acute marginal

 C

Diagonal

 D

All

Q. 5

Branches of R.C.A. (Rt. Coronary artery):

 A

Obtuse marginal

 B

Acute marginal

 C

Diagonal

 D

All

Ans. B

Explanation:

B. i.e. Acute marginal


Q. 6

The right coronary artery supplies all of the following parts of the conducting system in the heart except: 

 A

SA Node

 B

AV Node

 C

AV Bundle

 D

Right Bundle branch

Q. 6

The right coronary artery supplies all of the following parts of the conducting system in the heart except: 

 A

SA Node

 B

AV Node

 C

AV Bundle

 D

Right Bundle branch

Ans. D

Explanation:

D i.e. Right bundle branch 

Right coronary artery supply SA node (in 65% cases), AV node, AV bundle or Bundle of His and part of LBB (left bundle branch Q); where as Left coronary artery supply SA node (in 35% cases), RBB (right bundle branch) & part of LBB Q


Q. 7

The middle cardiac vein is located at the:

 A

Anterior interventricular sulcus

 B

Posterior interventricular sulcus

 C

Posterior AV groove

 D

Anterior AV groove

Q. 7

The middle cardiac vein is located at the:

 A

Anterior interventricular sulcus

 B

Posterior interventricular sulcus

 C

Posterior AV groove

 D

Anterior AV groove

Ans. B

Explanation:

B i.e. Posterior interventricular sulcus 

  • vein & posterior interventricular br. of right coronary artery is located in poster inter ventricular sulcus Q

Q. 8

True statement about Rt coronary artery (RCA)

 A

Diameter less than LCA

 B

RCA arises from anterior aortic sinus

 C

RCA supplies major part of right atrium and right ventricle

 D

All

Q. 8

True statement about Rt coronary artery (RCA)

 A

Diameter less than LCA

 B

RCA arises from anterior aortic sinus

 C

RCA supplies major part of right atrium and right ventricle

 D

All

Ans. A

Explanation:

A i.e. Diameter less than LCA; B i.e. RCA arises from anterior aortic sinus


Q. 9

Branch of Rt. Coronary artery:

 A

Obtuse marginal

 B

Acute marginal

 C

Posterior interventricular

 D

b & c

Q. 9

Branch of Rt. Coronary artery:

 A

Obtuse marginal

 B

Acute marginal

 C

Posterior interventricular

 D

b & c

Ans. D

Explanation:

B. i.e. Acute marginal; C. i.e. Posterior interventricular


Q. 10

The right coronary artery supplies all of the following parts of the conducting system in the heart except:

 A

SA Node

 B

AV Node

 C

AV Bundle

 D

Right Bundle branch

Q. 10

The right coronary artery supplies all of the following parts of the conducting system in the heart except:

 A

SA Node

 B

AV Node

 C

AV Bundle

 D

Right Bundle branch

Ans. D

Explanation:

Answer is D (Right bundle branch)

Right bundle is supplied by the Left coronary artery.

Right coronary artery supplies the SA node (in 65% cases), AV node, AV bundle or Bundle of His and part of left bundle branch(LBB)

Left cronoary artery supplies the right bundle branch (RBB, part of LBB and sometimes the SA node (in 35% cases),


Q. 11

Branches of left coronary artery are all of the following except:   

 A

Anterior interventricular branch

 B

Left diagonal artery

 C

Left atrial artery

 D

Posterior interventricular branch

 

Q. 11

Branches of left coronary artery are all of the following except:   

 A

Anterior interventricular branch

 B

Left diagonal artery

 C

Left atrial artery

 D

Posterior interventricular branch

 

Ans. D

Explanation:

The left coronary artery, which is usually larger than the right coronary artery, supplies the major part of the heart, including the greater part of the left atrium, left ventricle, and ventricular septum.

  • It arises from the left posterior aortic sinus of the ascending aorta.
  • It then enters the atrioventricular groove and divides into an anterior interventricular branch and a circumflex branch. Branches
  • The anterior interventricular (descending) branch /left anterior descending (LAD) runs downward in the anterior interventricular groove to the apex of the heart.
  • The anterior interventricular branch supplies the right and left ventricles with numerous branches that also supply the anterior part of the ventricular septum. One of these ventricular branches (left diagonal artery) may arise directly from the trunk of the left coronary artery.
  • The left circumflex artery (LCX) is the same size as the anterior interventricular artery. It winds around the left margin of the heart in the atrioventricular groove. A left marginal artery is a large branch that supplies the left margin of the left ventricle down to the apex. Anterior ventricular and posterior ventricular branches supply the left ventricle. Atrial branches supply the left atrium.

Posterior interventricular branch: It is typically a branch of the right coronary artery (80%, known as right dominance). Alternately, the Posterior interventricular branch can be a branch of the left circumflex coronary artery (20%, known as left dominance) which itself is a branch of the left coronary artery


Q. 12

Arterial supply to SA node is by:       

 A

Left anterior descending coronary artery

 B

Posterior interventricular (descending) artery

 C

Left coronary artery

 D

Right coronary artery

Q. 12

Arterial supply to SA node is by:       

 A

Left anterior descending coronary artery

 B

Posterior interventricular (descending) artery

 C

Left coronary artery

 D

Right coronary artery

Ans. D

Explanation:

The right coronary artery arises from the anterior aortic sinus of the ascending aorta and runs forward between the pulmonary trunk and the right auricle.

The artery of the sinuatrial node (branch of right coronary artery) supplies the SA node and the right and left atria; in 40% of individuals it arises from the left coronary artery.


Q. 13

Cardiac dominance is determined by coronary artery:

 A

Supplying circulation to the SA node

 B

Supplying circulation to the inferior portion of the interventricular septum

 C

Supplying circulation to the interatrial septum

 D

Supplying circulation to the anterior portion of the interventricular septum

Q. 13

Cardiac dominance is determined by coronary artery:

 A

Supplying circulation to the SA node

 B

Supplying circulation to the inferior portion of the interventricular septum

 C

Supplying circulation to the interatrial septum

 D

Supplying circulation to the anterior portion of the interventricular septum

Ans. B

Explanation:

In 85% of patients the right coronary artery (RCA) is said to be “dominant” because it supplies circulation to the inferior portion of the interventricular septum via the right posterior descending coronary artery/posterior interventricular artery.

In these cases the RCA travels to the cross-section of the AV groove and the posterior interventricular (IV groove). Here, it gives rise to the right posterior descending coronary artery (PDA) branch which travels in the posterior IV groove and gives off several septal perforator branches (SP). The SP supply blood to the lower portion of the IV septum. Generally, the dominant RCA also gives rise to the AV nodal branch which supplies blood to the AV node

The dominant RCA also provides the right postero-lateral (PLA) branch to the lower postero-lateral portion of the left ventricle.

The sinus or sino-atrial (SA) node branch originates in the proximal portion of the RCA in 60% of cases and as a left atrial branch of the Cx in the remaining 40% of cases. This is unrelated to whether the artery is “dominant” or not.


Q. 14

The Diagram repersents the blood supply of Heart. Identify the Vessel Marked B in the Diagram ?

 A

Left Coronary Artery

 B

Left Circumplex Artery

 C

Left Anterior Descending Branch  (LAD)

 D

Right Cornorary Artery

Q. 14

The Diagram repersents the blood supply of Heart. Identify the Vessel Marked B in the Diagram ?

 A

Left Coronary Artery

 B

Left Circumplex Artery

 C

Left Anterior Descending Branch  (LAD)

 D

Right Cornorary Artery

Ans. B

Explanation:


Q. 15

Right coronary artery supplies all, except‑

 A

Anterior 2/3 of ventricular septum

 B

SA node

 C

AV node

 D

LBB

Q. 15

Right coronary artery supplies all, except‑

 A

Anterior 2/3 of ventricular septum

 B

SA node

 C

AV node

 D

LBB

Ans. A

Explanation:

Right coronary artery supplies

(i) SA node (in 65%),

(ii) whole conducting system (AV bundle, bundle of his, part of left bundle branch) except RBB and part of left branch of AV bundle,

(iii) posterior part of ventricular septum,

(iv) most of right ventricle except small part adjoining anterior interventricular groove and small part of left ventricle adjoining posterior interventricular groove.

Left coronary artery supplies

(i) most of the left atrium,

(ii) most of the left ventricle including apex,

(iii) small part of right ventricle odjoining anterior interventricular septum,

(iv) anterior 2/3 of ventricular septum,

(v) RBB, LBB 

(vi) SA node in 35% of cases.


Q. 16

True about SA node are all except ‑

 A

Supplied by nodal artery

 B

Primary pacemaker

 C

Supplied by left vagus nerve

 D

Made up of nodal cells and connective tissue

Q. 16

True about SA node are all except ‑

 A

Supplied by nodal artery

 B

Primary pacemaker

 C

Supplied by left vagus nerve

 D

Made up of nodal cells and connective tissue

Ans. C

Explanation:

 

  • SA node is located in the upper part of crista terminalis at the junction of SVC and the right atrium.
  • It is the pacemaker of the heart and generates impulse at a rate of 70-100/min.
  • SA node is suplied by nodal artery, a branch of RCA in 65% cases and a branch of circumflex branch of LCA in 35% cases.
  • SA node is supplied by right vagus/parasympathetic (inhibitory) and right Sympathetic (excitatory) system as it develops from structures on the right side of embryo.
  • The SA node consists of connective tissue stroma containing an irregular whorled network of cardiac nodal cells, the SA nodal artery and numerous nerve endings (postganglionic parasympathetic and postganglionic sympathetic).

Q. 17

The artery represented below supplies all of the following parts of the conducting system in the heart except?

 A

SA Node

 B

AV Node

 C

AV Bundle

 D

Right Bundle branch

Q. 17

The artery represented below supplies all of the following parts of the conducting system in the heart except?

 A

SA Node

 B

AV Node

 C

AV Bundle

 D

Right Bundle branch

Ans. D

Explanation:

 

The arrow represents Right coronary artery.

D i.e. Right bundle branch 

Right coronary artery supply SA node (in 65% cases), AV node, AV bundle or Bundle of His and part of LBB (left bundle branch ); where as Left coronary artery supply SA node (in 35% cases), RBB (right bundle branch) & part of LBB.



Malcare WordPress Security