Lecture 10 Cardiology

1
Lecture 10 Cardiology
2

• ___________ is the study of the heart and its
  diseases
• The heart is located in the space between the
  lungs known as the ___________.
• The heart may be regarded as a double pump and
  thus circulates blood in ______ circulations -
  the _________ and the ______.

3

• Location
• w/i mediastinum oblique orientation
• 2nd rib ? 5th intercostal space
• 2/3 mass to left of mid-sternal line
• Base posterior surface
• Apex points forward towards left hip
• Auscultation point of maximum between 5th 6th
  ribs

4
(No Transcript)
5

• About ________ of the mass of the heart is to the
  _________ of the midline.
• A mid-sagital section through the mediastinum
  would leave ______ of the mass of the heart in
  the left section.
• The apex of the heart is at the height of the
  _____ rib.

6

• Coverings pericardium
• Fibrous pericardium collagen reinforced loose
  fitting sac
• Lined internally by parietal pericardium serous
  membrane
• Attaches to major vessels and diaphragm
• Visceral pericardium
• Adheres directly to surface of heart
• epicardium outermost layer of heart wall
• Pericardial cavity
• pericardiatis

7
(No Transcript)
8

• The double layered serous membrane structure
  which encloses the heart is the __________.
• The layer of this membrane which lies directly
  against the muscle of the heart is known as the
  _____________
• The most superficial layer of the loose fitting
  sac about the heart is the __________
• The space between the inner and outer membranes
  filled with ________ is known as the _________

9

• Wall of Heart
• Epicardium _____________
• Myocardium
• Interlaced bundles of _______________
• Reinforced internally by Fibrous Skeleton of
  Heart
• Insertion for _______________ _____________
• Thickenings support blood vessels valves
• Directs spread of electrical signal w/i
  myocardium
• Endocardium endothelium tissue type?
• Smooth continuous lining with blood vessels
  exiting heart

10
(No Transcript)
11

• Cardiac Muscle Forms Myocardium
• Fibers short/fat/branched/interconnected
• 1-2 nuclei
• Surrounded by endomysium loose connective
  tissue
• Numerous blood vessels
• Forms ???
• Numerous mitochondria 25-35 volume of cells
• Intercalated discs physical/electrical
  connection
• Gap junctions allow passage of ions
• Desmosomes
• anchor cells together - Anchor point for
  myofibrils
• Acts as functional syncytium electrically
  coupled

12
(No Transcript)
13

• External Features
• Apex
• Base
• Sulci
• Auricle(s)
• Ventricles
• Pulmonary trunk
• Ascending aorta
• Superior vena cava
• Auricle of right atrium
• Ligmentum arteriosum
• Brachiocephalic trunk
• Left common carotid
• Left subclavian artery

right
left
14

• External Features
• Auricle of right atrium
• Left ventricle
• Posterior interventricular sulcus
• Left atrium
• Inferior and superior vena cava
• Coronory sinus
• Right and Left pulmonary arteries
• Aorta
• Right atrium

15

• Atria
• Ventricles
• Valves features
• Tricuspid
• Bicuspid
• Semilunar
• Fossa ovale
• Trabeculae carneae

16

• Internal Structure of Heart - Atria
• Thin walled - superior
• Receive blood from systemic/pulmonary circulation
• Pump blood to ventricles
• Auricles allow addition capacity
• Valves prevent back-flow
• Tricuspid right
• Bicuspid or mitral left
• Right
• Pectinate muscles
• Fossa ovalis remnant of foramen ovale in
  interatrial septum
• Left
• Smooth walled
• Forms most of the base of the heart
• Receives blood from lungs - 4 pulmonary veins (2
  right 2 left)

17

• Internal Structure of Heart Right Ventricle
• Relatively light walled pumps blood to
  pulmonary circuit
• Forms most of anterior surface of heart
• Squeezes blood against interventricular septum
• Moderator band
• Contains conducting fibers
• Trabeculae carneae
• papillary muscles
• Cone shaped
• Conus arteriosus at superior end terminates at
  pulmonary semi lunar valve

18

• Internal Structure of Heart Left Ventricle
• Heavy walled pumps blood to systemic circuit
• Round in x-section
• Contracts longitid. and in diameter
• No Moderator band
• Prominent trabeculae carneae
• 2 large papillary muscles
• Blood enters aorta
• Aortic semi lunar valve
• Aortic sinus behind cusps

19
(No Transcript)
20
(No Transcript)
21

• Valves - Atrioventricular
• Right Tricuspid
• Left Mitral or Bicuspid
• Valve components
• Ring of supporting connective tissue
• Connective tissue cusps covered with
  endocardium
• Cordae tendineae
• Papillary muscles
• Contract prior to other ventricular musculature
• Prevent prolapse of valve cusps

22
The valves prevent backflow of blood
Pulmonary valve
Aortic valve
Tricuspid valve
Bicuspid (mitral valve)
23

• Semilunar Valves
• Aortic
• Aortic sinus
• exit point for cardiac circulation
• Prevent sticking of cusps to walls of aorta
• Pulmonary
• In pulmonary trunk
• No valves to prevent back-flow from atria
• Minimal back-flow does occur
• Myocardium compresses around opening to vessels

24

• Valve Operation and Sounds
• Opening and closure due to pressure difference
• Lubb
• Closure of AV valves
• Dubb
• Closure of semi lunar valves
• Ascultation
• Listening diagnostic for valve defects

25
AuscultationNormal Heart vs. Abnormal Heart
(Mitral Valve Prolapse)
Lub-dub - normal
Chug-a-lug prolapsed mitral valve
26

• Conduction System of Heart
• Autorhythmic Cells
• Cells fire spontaneously, act as pacemaker and
  form conduction system for the heart
• SA node
• cluster of autorhythmic cells in wall of Rt.
  Atria
• begins heart activity that spreads to both atria
• excitation spreads to AV node
• AV node
• in atrial septum, transmits signal to bundle of
  His
• AV bundle of His
• the connection between atria and ventricles
• divides into bundle branches purkinje fibers,
  large diameter fibers that conduct signals quickly

27

• The apex of the heart is which chamber?
• Pectinate muscles are found in which chamber?
• The fossa ovalis is found in the _________
• Blood passing from the left atrium to the left
  ventricle passes what valve?
• Blood entering the right atrium does so from what
  vessels?

28
Internal Conduction System

• Sinoatrial node (SA, pacemaker).
• Atrioventricular node (AV).
• Atrioventricular bundle.
• Right and left bundle branches
• Purkinje Fibers.

29

• Heart Rate
• SA node establishes basic contraction rate
• Modified by nervous/hormonal input
• Acetylcholine slows from SA rate
• Norepinephrine speeds
• Resting rate 70-80 contractions/min
• Bradycardia abnormally slow heart rate
• Trachycardia rapid heart rate

30

• Intrinsic heart rate established by SA node
• Modified by extrinsic impulses from cardiac
  centers in medulla
• Cardioacceleratory centers ? sympathetic spinal
  nerves
• Cardioinhibitory center ? parasympathetic dorsal
  vagus nucleus ? via vagus nerve

31

• Impulses that slow heart rate arise in the
  _______________ of the _________
• Impulses that speed heart rate arrive at the
  heart in the cardiac nerve and are part of the
  ____________ nervous system.

32

• Path of blood flow
• Blood enters right atria from
• Systemic circulation inferior and inferior vc
• Cardiac circulation via cardiac sinus
• Atrial systole blood moves into right ventricle
  past tricuspid valve
• Ventricular systole (atrial diastole) blood
  flows into pulmonary trunk pulmonary semilunar
  valves ? pulmonary circulation
• Enters left atrium
• Atrial systole enters left ventricle past
  bicuspid valve
• Left ventricle to aorta aortic semilunar valves
• Fetal circulation differs

33
Electrocardiogram---ECG or EKG

• EKG
• Action potentials of all active cells can be
  detected and recorded
• P wave
• atrial depolarization
• P to Q interval
• conduction time from atrial to ventricular
  excitation
• QRS complex
• ventricular depolarization
• T wave
• ventricular repolarization

34
Cardiac Cycle
35

• Coronary Circulation
• Left coronary artery Right coronary artery
• Branch off aorta above aortic semilunar valve
• First vessels leaving aorta
• Right Coronary ?
• Atrial branches to right atrium
• Ventricular branches to right ventricle and
  interventricular septum
• Conducting system
• Left Coronary ?
• Left atrium/ ventricle
• Patterns may vary with individual anastomoses
  form

36
Coronary Veins

• Collects wastes from cardiac muscle
• Drains into a large sinus on posterior surface of
  heart called the coronary sinus
• Coronary sinus empties into right atrium

37
Coronary Artery Disease

• Heart muscle receiving insufficient blood supply
• narrowing of vessels---atherosclerosis, artery
  spasm or clot
• atherosclerosis--smooth muscle fatty deposits
  in walls of arteries
• Treatment
• drugs, bypass graft, angioplasty, stent

38
Lung Bypasses in Fetal Circulation
Ductus arteriosus is shortcut from pulmonary
trunk to aorta bypassing the lungs.
Foramen ovale is shortcut from right atria to
left atria bypassing the lungs.