Post on 05-Apr-2018
8/2/2019 11-Ch 18 Lecture A
1/33
The Cardiovascular System: TheHeart: Part A
Marieb and Hoehn, 8 th ed.
Dr. Saheba
1
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
2/33
Heart AnatomySize of a fistLocation
In the mediastinum
between second rib and fifth intercostal spacesuperior surface of diaphragmTwo-thirds to the left of the midsternal line Anterior to the vertebral column, posterior tothe sternum
Enclosed in pericardium, a double-walled sac
PLAY Animation: Rotatable heart
2
Dr. Saheba
http://rotatable_heart.mov/http://rotatable_heart.mov/8/2/2019 11-Ch 18 Lecture A
3/33
Figure 18.1c
(c)
Superiorvena cava
Left lung
Aorta Parietalpleura (cut)
Pericardium(cut)
Pulmonarytrunk
Diaphragm
Apex ofheart
3
Pericardium Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
4/33
Pericardium1. Superficial fibrous pericardium Protects, anchors, and prevents overfilling2. Deep two-layered serous pericardium
Parietal layer - lines the internal surface of thefibrous pericardium Visceral layer (epicardium) on external surfaceof the heartSeparated by fluid-filled pericardial cavity todecreases friction
4
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
5/33
5
Layers of the Heart Wall1. Epicardium visceral layer of the serous pericardium
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
6/33
Layers of the Heart Wall2. Myocardium
Spiral bundles of cardiac muscle cellsFibrous skeleton of the heart connective
tissue1. Anchors - muscle fibers2. Supports - great vessels and valves
3. Limits - spread of action potentials3. Endocardium - continuous with
endothelial lining of blood vessels
6
Cardiacmusclebundles
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
7/33
Chambers4 chambers1. Two atria
Separated internally by the interatrial septumCoronary sulcus (atrioventricular groove)encircles the junction of the atria and ventricles Auricles increase atrial volume
2. Two ventricles
Separated by the interventricular septum Anterior and posterior interventricular sulcimark the position of the septum externally
7
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
8/33
Figure 18.4b
(b) Anterior view
Brachiocephalic trunk
Superior vena cava
Right pulmonaryarteryAscending aorta Pulmonary trunk
Right pulmonary
veins
Right atrium
Right coronary artery(in coronary sulcus) Anterior cardiac vein
Right ventricle Right marginal artery
Small cardiac vein
Inferior vena cava
Left common carotidarteryLeft subclavian artery
Ligamentum arteriosum
Left pulmonary artery
Left pulmonary veins
Circumflex artery
Left coronary artery(in coronary sulcus)
Left ventricle
Great cardiac vein Anterior interventricularartery (in anteriorinterventricular sulcus)
Apex
Aortic arch
Auricle of
left atrium
8
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
9/33
Atria: The Receiving Chambers Walls are ridged by pectinate muscles
A. Vessels entering right atrium1. Superior vena cava2. Inferior vena cava3. Coronary sinus
B. Vessels entering left atrium
1. Right and2. left pulmonary veins
9
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
10/33
Ventricles: Discharge Blood1. Walls are ridged by trabeculae carneae2. Papillary muscles project into the
ventricular cavities3. Vessel leaving the right ventricle
Pulmonary trunk
4. Vessel leaving the left ventricle Aorta
10
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
11/33
Aorta
Left pulmonary
artery Left atrium Left pulmonaryveins
Mitral (bicuspid)valve
Aortic valve
Pulmonary valve Left ventricle Papillary muscle Interventricularseptum Epicardium Myocardium Endocardium
(e) Frontal section
Superior vena cava
Right pulmonaryartery Pulmonary trunk Right atrium
Right pulmonary
veins Fossa ovalis Pectinate muscles
Tricuspid valve Right ventricle Chordae tendineae Trabeculae carneae Inferior vena cava
11
Dr. Saheba
Figure 18.4e
8/2/2019 11-Ch 18 Lecture A
12/33
Heart - Pathway of BloodThe heart is two side-by-side pumps
1. Right side - for the pulmonary circuitblood to and from the lungs
2. Left side - for the systemic circuitblood to and from all body tissues
12
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
13/33
Oxygen-rich,CO 2-poor blood Oxygen-poor,CO
2-rich blood
Capillary bedsof lungs wheregas exchangeoccurs
Capillary beds of allbody tissues wheregas exchange occurs
Pulmonary veins Pulmonary arteries
PulmonaryCircuit
SystemicCircuit
Aorta and branches
Left atrium
Heart
Left ventricle Right atrium
Right ventricle
Venae cavae
13
Dr. Saheba
Figure 18.5
8/2/2019 11-Ch 18 Lecture A
14/33
PLAY Animation: Rotatable heart (sectioned)
Blood Through the HeartRight atrium tricuspid valve right ventricleRight ventricle pulmonary semilunar valve pulmonary trunk pulmonary arteries lungs
Lungs pulmonary veins left atriumLeft atrium bicuspid valve left ventricleLeft ventricle aortic semilunar valve aorta Aorta systemic circulation
14
Dr. Saheba
http://rotatable_heart_sectioned.mov/http://rotatable_heart_sectioned.mov/8/2/2019 11-Ch 18 Lecture A
15/33
Blood Through the HeartEqual volumes of blood - to the pulmonary andsystemic circuitsPulmonary circuit is:
a short,low-pressure circulationSystemic circuit blood
much resistance inthe long pathways
Anatomy of the ventricles reflects thesedifferences
15
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
16/33
Figure 18.6
Rightventricle
Leftventricle
Interventricularseptum
16
Dr. Saheba
h b
8/2/2019 11-Ch 18 Lecture A
17/33
Coronary CirculationSupply - to the heart muscle itself Arterial supply varies considerably andcontains many anastomoses (junctions)among branchesCollateral routes provide additional routesfor blood delivery
17
Dr. Saheba
D S h b
8/2/2019 11-Ch 18 Lecture A
18/33
Coronary Circulation Arteries
1. Right coronary and2. left coronary (in atrioventricular groove),3. marginal,4. circumflex, and5. anterior interventricular arteries
Veins1. Small cardiac,2. anterior cardiac, and3. great cardiac veins
18
Dr. Saheba
D S h b
8/2/2019 11-Ch 18 Lecture A
19/33
Figure 18.7a
Right
ventricle
Rightcoronaryartery
Right
atrium
Rightmarginalartery
Posterior interventricular artery
Anterior interventricular artery
Circumflexartery
Leftcoronaryartery
Aorta
Anastomosis(junction ofvessels)
Leftventricle
Superiorvena cava
(a) The major coronary arteries
Left atrium
Pulmonarytrunk
19
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
20/33
Dr Saheba
8/2/2019 11-Ch 18 Lecture A
21/33
Figure 18.4d
(d) Posterior surface view
Aorta Left pulmonaryartery Left pulmonaryveins Auricle of leftatrium Left atrium
Great cardiacvein
Posterior veinof left ventricle Left ventricle
Apex
Superior vena cava
Right pulmonary artery Right pulmonary veins
Right atrium
Inferior vena cava
Right coronary artery(in coronary sulcus)
Coronary sinus
Posterior
interventricularartery (in posteriorinterventricular sulcus) Middle cardiac vein Right ventricle
21
Dr. Saheba
Dr Saheba
8/2/2019 11-Ch 18 Lecture A
22/33
Homeostatic Imbalances Angina pectoris
Thoracic pain caused by a fleeting deficiency inblood delivery to the myocardium
Cells are weakenedMyocardial infarction (heart attack)
Prolonged coronary blockage
Areas of cell death are repaired withnoncontractile scar tissue
22
Dr. Saheba
Dr Saheba
8/2/2019 11-Ch 18 Lecture A
23/33
Heart ValvesEnsure unidirectional blood flow through the heart
1. Atrioventricular (AV) valvesPrevent backflow into the atria when ventricles contract
2. Tricuspid valve (right)
3. Mitral valve (left)Chordae tendineae anchor AV valve cusps to papillary muscles
4. Semilunar (SL) valvesPrevent backflow into the ventricles when ventricles relax
i. Aortic semilunar valveii. Pulmonary semilunar valve
23
Dr. Saheba
Dr Saheba
8/2/2019 11-Ch 18 Lecture A
24/33
Pulmonary valve Aortic valve Area of cutaway
Mitral valve Tricuspid valve
Myocardium
Tricuspid(right atrioventricular)valve Mitral(left atrioventricular)valve
Aorticvalve
Pulmonaryvalve
(b)
Pulmonary valve Aortic valve Area of cutaway
Mitral valve Tricuspid valve
Myocardium
Tricuspid(right atrioventricular)valve
(a)
Mitral(left atrioventricular)valve Aortic valve
Pulmonaryvalve Fibrous
skeleton Anterior
24
Dr. Saheba
Figure 18.8a
Dr Saheba
8/2/2019 11-Ch 18 Lecture A
25/33
Pulmonary valve Aortic valve Area of cutaway
Mitral valve Tricuspid valve
Myocardium
Tricuspid(right atrioventricular)valve Mitral(left atrioventricular)valve
Aorticvalve
Pulmonaryvalve
(b)
25
Dr. Saheba
Figure 18.8b
Dr Saheba
8/2/2019 11-Ch 18 Lecture A
26/33
Figure 18.8c
Pulmonaryvalve
AorticvalveArea ofcutaway Mitralvalve
Tricuspidvalve
Chordae tendineaeattached to tricuspid valve flap
Papillarymuscle
(c)
26
Dr. Saheba
Dr Saheba
8/2/2019 11-Ch 18 Lecture A
27/33
PulmonaryvalveAortic valve Area ofcutaway Mitral valve Tricuspidvalve
Mitral valve Chordaetendineae
Interventricularseptum
Myocardium
of left ventricle
Opening of inferiorvena cava
Tricuspid valve
Papillarymuscles
Myocardiumof rightventricle
(d) 27
Dr. Saheba
Figure 18.8d
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
28/33
Figure 18.9
1 Blood returning to theheart fills atria, puttingpressure againstatrioventricular valves;atrioventricular valves areforced open.
1 Ventricles contract, forcingblood against atrioventricularvalve cusps.
2 As ventricles fill,atrioventricular valve flapshang limply into ventricles.
2 Atrioventricular valvesclose.
3 Atria contract, forcingadditional blood into ventricles.
3 Papillary musclescontract and chordaetendineae tighten,preventing valve flapsfrom everting into atria.
(a) AV valves open; atrial pressure greater than ventricular pressure
(b) AV valves closed; atrial pressure less than ventricular pressure
Direction ofblood flow
Atrium
Ventricle
Cusp ofatrioventricularvalve (open)
Chordaetendineae
Papillarymuscle
Atrium
Blood inventricle
Cusps ofatrioventricularvalve (closed)
28
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
29/33
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
30/33
Microscopic Anatomy of
Cardiac MuscleCardiac muscle cells are - striated, short, fat,branched, and interconnected
Connective tissue (endomysium) connects to thefibrous skeletonT tubules are wide but less numerous; SR issimpler than in skeletal muscleNumerous large mitochondria (25 35% of cell volume)
30
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
31/33
Nucleus
Desmosomes Gap junctions
Intercalated discs Cardiac muscle cell
(a)
31
Figure 18.11a
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
32/33
Microscopic Anatomy of
Cardiac MuscleIntercalated discs: junctions between cellsanchor cardiac cells
Desmosomes prevent cells fromseparating during contractionGap junctions allow ions to pass;
electrically couple adjacent cellsHeart muscle behaves as a functionalsyncytium
32
Dr. Saheba
8/2/2019 11-Ch 18 Lecture A
33/33
Figure 18 11b
Nucleus
Nucleus
I band A band
Cardiacmuscle cell
Sarcolemma
Z disc
Mitochondrion
Mitochondrion
T tubule
Sarcoplasmicreticulum
I band
Intercalateddisc
(b)