Cardiovascular System: Morphology

Question 1

The Heart
State the position of the heart
. Superior
. Right border
. Apex

Answer 1

Superior - 2nd intercostal space (4cm side)
Right norder - 3rd costal cartilage to 6th costal cartilage
. Apex - 5th intercostal space in the mid clavicular line

Question 2

State the location of the heart in the chest

Answer 2

Middle mediastinum in the pericardium

Question 3

Pericardium - … layered sac

Answer 3

doubled

Question 4

External pericardial layer
. what is it
. purpose
. clinical relevance

Answer 4

. fibrous pericardium
. prevents excessive distension of the heart
. stabbing in the chest = leads to filling of the pericardium with blood which compresses the heart

Question 5

Internal pericardial layer:
. what is it called
. is it further divided - elaborate

Answer 5

. Internal pericardial layer = serous pericardium
. further = divided into 2 layers
. layers = separated by the pericardial cavity
. pericardial cavity = contains a thin layer of fluid - allowing the heart to move in the pericardial sac
. Parietal layer - lines the internal surface of the fibrous pericardium
. Visceral layer - forms the epicardium, the outer surface of the heart

Question 6

Vessels of the heart
. Name the venous structures draining to the heart

Answer 6

. Superior vena cava
. Inferior vena cava
. Pulmonary veins ( 2 right & 2 left)
. Coronary sinus

Question 7

Coronary sinus - elaborate

Answer 7

. runs in the posterior atrioventricular groove and drains into the right atrium
. It receives blood from:
. Great cardiac vein (anterior interventricular groove) at its left end
. middle cardiac vein ( inferior interventricular groove)
. small cardiac vein (lower border of the heart) at its right end

Question 8

Arterial structures leaving the heart

Answer 8

. Aorta from left ventricle
. Pulmonary artery from right ventricle

Question 9

Interior of the heart
. Atria
Structure
wall - thickness reflect what?

Answer 9

Thin walled = most of the filling of the ventricles is due to the relaxation of the ventricles rather than atrial contraction

Question 10

Auricle (ear shaped projection)
Right atrium - structure recall and read

Answer 10

. Anterior surface of the heart
. Rough walled part - terminal crest and pectinate muscles derived from primitive atrium
. Smooth walled part derived from sinus venosus and interatrial septum
. Fossa ovalis = marks the position of the interatrial foramen - remnant of the R/L atrial shunt
. Blood from the SVC + IVC & the coronary sinus

Question 11

Rough walled part of RA is
….
derived from…

Answer 11

• terminal crest and pectinate muscle
• primitive atrium

Question 12

Smooth walled part of RA is derived from ……

Answer 12

sinus venosus & interatrial septum

Question 13

Fossa ovalis = ?

Answer 13

Marks the position of the foetal interatrial foramen - remnant of the R/L atrial shunt

Question 14

RA receives blood from:

Answer 14

Superior and inferior vena cava and the coronary sinus

Question 15

Left atrium + auricle
. position
. structure / texture

Answer 15

. Posterior surface of the heart, in front of the posterior mediastinum
. Entriely smooth walled, derived from incorporation of the primitive pulmonary veins
. The left auricle extends onto the anterior surface of the heart and is rough walled as it was from primitive atrium

Question 16

Ventricles
Right ventricle - valve AV

Answer 16

Right AV valve - tricuspid valve
. septal, anterior and posterior cusps
. attached to papillary muscles by cordae tendinae

Question 17

RV - semilunar valve

Answer 17

RV - semilunar valve
3 semilunar cusps
. left, right, posterior cusps

Question 18

RV
wall texture & outflow tract

Answer 18

roughed walled - trabeculae carnae
outflow tract -> pulomnary trunk is smooth walled

Question 19

LV
-AV valve

Answer 19

Left AV valve - biscupid / mitral valve
. Anterior and posterior cusps
. Cordae tendinae and papillary muscles

Question 20

Left Ventricle
Wall thickness

Answer 20

Thicker walls
- pumps blood to the systemic circulation at a higher pressure
- + is also rough due to trabeculae carnea

Question 21

Left ventricle - semilunar valve

Answer 21

. left, right and anterior cusps
. clinical relevance - bicuspid aortic valve: semilunar valve has 2 instead of the usual 3 cusps
consequences:
increased backflow, reduced systemic circulation - symptoms = fatigue, hypoxia, muscle weakness, fainting
+ increased pressure in the LV - cardiac hypertrophy - fibrillatiion
Treatment = valve replacement & pacemaker

Question 22

Valves
. Recall
- AV valves
- Outflow tract valves

Answer 22

AV valves ( bicuspid + tricuspid)
reflex prevenyed by the cordae tendinae and papillary muscles
. outflow tract valves (pulmonary and aortic): 3 semilunar cusps with thickened margins, reflux preventing by blood bluging the cusps, pushing them together
. Valves = supported by fibrous skeleton + this also provides electrical isolation of the atria and ventricles

Question 23

Valves - clinical significance

Answer 23

stenosis - restricted blood flow + regurgitation due to improper opening & closing of the valve - increases pressure in the ventricle + cardiac hypertrophy