THE CIRCULATORY SYSTEM Ch. 18 The HEART - PowerPoint Presentation

Slide1

THE CIRCULATORY SYSTEM

Ch. 18 The HEART

Slide2

Slide3

ASSIGNMENT

: Most Of The Anatomy We Have Already Done In The Lab, So Make Sure To Do The

* of slide 1 through 29.

As I Will Likely Not Take The Time To Review This Material.

Slide4

*PARTS OF THE CARDIOVASCULAR SYSTEM

*1. *2. *3.

Slide5

Slide6

I. Heart Anatomy

*A. Size, Location, and Orientation*Size: *Location: *Orientation of Apex & Base

Point of

maximal

intensity

(PMI)

Diaphragm

Sternum

2nd rib

Midsternal line

base

apex

STUDY QUESTION EXAMPLES

:

1. Describe the Heart’s Size, Location, Orientation, Coverings, and Wall Layers

Slide7

B. Coverings of the Heart

2A Review

See text p. 18

*

Serous Membranes

-

*

P_________

-

*

V_________

-

*

for Heart named:

*

Cavity

-

*

and that cavity

is in the

M____________________

(page 665)

Slide8

B. Coverings of Heart …

Figure 11.1a–b

1. *Pericardium: Description = double-walled sac Fibrous pericardium – Function: Protection & Anchoring Parietal pericardium Visceral Pericardium = epicardium = is the same as the Visceral Pericardium*Serous fluid:

Outer

Sac

Inner

Sac

Slide9

Figure 18.1c

(c)

Superior

vena cava

Left lung

Aorta

Parietal

pleura (cut)

Pericardium

(cut)

Pulmonary

trunk

Diaphragm

Apex of

heart

The Heart = pump of the cardiovascular system

Slide10

C. *Layers of the Heart Wall

Figure 11.2b

1.

*Epicardium 2. *MyocardiumWhat type of tissue: 3. *Endocardium – endothelium: is what type of tissue

Slide11

D. Fibrous Cardiac Skeleton (page 666)

Cardiac

muscle

bundles

Connective Tissue*Thickest in what areas and why? Electrical Characteristics: *Can action potentials pass through it? Importance: limits the spread of action potentials through the cardiac muscle to certain areas, or pathways (… in “III-A. Electrical Events”)

2. What is the Fibrous Skeleton and what is its purpose?

Slide12

*Atria:*Auricles*Ventricles:*Interatrial & Interventricular Septa: location & description?*Sulci = describe?Coronary Sulcus = Atrio-Ventricular Sulcus*Anterior Interventricular Sulcus: location? What is within it?*Posterior Interventricular Sulcus: same questions as above?

E. Chambers and Associated Great Vessels

Overview

Slide13

E. Chambers and Associated Great Vessels …1. *Atria

*Pectinate MusclesFossa Ovalis adult, indents inForamen Ovale: hole with flap to bypasses RV & lungs in fetusRight *Superior Vena Cava: Blood from where to where?*Inferior Vena Cava: same?Coronary Sinus: collects blood from Coronary veinsLeft*Pulmonary Veins: from where to where?

Slide14

2. *Ventricles& Blood & Vessels– 2 pumps

Figure 11.4

Right vs. Left

*

Shapes

:

*

Thickness,

why?

*

Trabeculae

carneae

*

Papillary Muscles

*

Right: Pulmonary Trunk



blood goes where?

*

Left: Aorta–

Blood goes where?

*

Coronary Arteries:

Branch of ?

Blood goes where?

Slide15

1. 2 PUMP SYSTEM two circulationsBlood Flow Direction: Pulmonary Circulation: Blood vessels from R Ventricle  Lungs  Left AtriaSystemic Circulation: Blood vessels from Left Ventricle  Body  Right AtriaBlood Vessels in Pathway: Sup & Inf Vena Cava & Coronary Sinus  RA  RV  Pulmonary Trunk  Pulmonary Arteries  Lungs  Pulmonary Veins  LA  LV Aorta  Cells & Coronary Arteries

5. Describe the path a blood cell would take starting with the Right Atria and ending back at the RA.

F

. Pathway of Blood Through the

Heart

Slide16

G. *Coronary Circulation =?

Figure 11.2a

*

Coronary Arteries:

a)

*

Supply the heart muscle w what?

b)

*

Branch from: 2. *Branches of the Left Coronary Artery =3. *Branches of the Right Coronary Artery =

Slide17

Figure 18.7a

Right

coronary

artery

Right

marginal

artery

Posteriorinterventricularartery

Anteriorinterventricularartery

Circumflexartery

Leftcoronaryartery

Aorta

Slide18

Figure 18.7b

Superior

vena cava

Anterior

cardiac

vein

s

Small cardiac vein

Middle cardiac vein

Great

cardiac

vein

Coronary

sinus

(b) The major cardiac veins

Pulmonary Trunk

Aorta

G. Coronary Circulation …

5. Cardiac Veins

-

*

Function?

-

Coronary

Sinus

=

pouch that collects

deoxygenatied

blood from the coronary veins

Slide19

6. Homeostatic ImbalancesSTUDENTS DO

*

Angina pectoris

*

Myocardial

Infarction (heart attack

)

Slide20

H. FETAL CIRCULATION

*

Lungs are functional?

1. Alteration of Atrial

Blood FlowForamen OvaleAfter Birth = Fossa OvalisAlteration of Blood Flow from Pulmonary TrunkDuctus Arteriosis duct moves blood out of Pulmonary trunckLigamentum Arteriosum

3. Umbilical Cord with Umbilical Artery and Veins

Slide21

I. Heart Valves 1. Function: prevent backflow of blood

2. * Atrioventricular (AV) valves—between what cavities? *Bicuspid (mitral) valve __________ side*Tricuspid valve ___________sideParts: Cusps, Chordae Tendinae, Papillary muscles*When ventricles contract: these valves do what?

Students Do

Slide22

H. Heart Valves …

*Parts: Describe and give functionCuspsChordae TendinaePapillary muscles*What happens to these valves when the atria and then the ventricles contract?

Slide23

Figure 11.5a, step 1

Returning blood fills

relaxed atria and

ventricles

–

open

AV valves

Ventricles

3. Operation of the AV valves

AV valves open

(a)

H. Heart Valves

…

Slide24

Figure 11.5a, step 2

Returning blood fills relaxed atria and ventricles (open AV valves)

Atria contract

– more blood forced into

ventricles–

AV valves still open

Relaxed

Ventricles

Operation of the AV

valves …

AV valves open

(a)

Slide25

Figure 11.5a, step 4

Ventricles contract

,

blood forcedagainst AV flaps / into arteriesAV valves close preventing backflow to atria (LUB of LUB-dup sound)

(a)

Operation of the AV valves …

Chordae tendineae

prevent valve flaps from everting

Slide26

H. Heart Valves …4. Semilunar valves Function:

Figure 11.2c

Pulmonary semilunar valve –

__R_sideAortic semilunar valve – __L_side*When Ventricles contract, what happens to valve?

3 cusps each

Slide27

Figure 11.5b, step 1

As

ventricles contract

semilunar

valves are forced open

Aorta

Pulmonary

trunk

Semilunar valve

open

5. Operation of the semilunar valves

(b)

Slide28

Figure 11.5b, step 2

Aorta

Pulmonary

trunk

Semilunar valve

open

Semilunar valve

closed

As ventricles relax

, blood flows back from arteries, forcing semilunar valves to close

Operation of the semilunar valves …

(b)

All this to ensure that…

‘dup’ of LUB-dup sound

Slide29

*

Review Skeletal Muscles (Text pages 282-288)*Number of nuclei?*Sarcolemma =*Myofibrils =*Sarcoplasmic Reticulum =*Sarcomeres =*T-tubules =*Triads =

II. Cardiac Muscle Fibers—Histology A. Microscopic Anatomy of Cardiac Cells

Thin Myofilaments

Thick Myofilaments

Skeletal Muscle Cell

Scaroplasmic

Reticulum

T Tubules

Myofibrils

Sarcomere

Slide30

A. Microscopic Anatomy of Cardiac Cells…

1.

*Cardiac muscle cell characteristics: (text pp. 676-677)2. Endomysium anchored to: Fibrous Skeleton .3. T tubules: Fewer . Triads? None . 4. SR simpler  Source of Ca+2: from outside cell 5. Mitochondria: Many & Large to resist fatigue

Nucleus

Cardiac

muscle cell

Sarcolemma

Z disc

Mitochondrion

Mitochondrion

T tubule

Sarcoplasmic

reticulum

Intercalated

disc

Slide31

A. Microscopic Anatomy of Cardiac Cells …

6. *Intercalated discs = Desmosomes (tight anchoring) & Gap Junctions (help electrical stimulation to move quickly from cell to cell)7. Functional Syncytium: as a single coordinated unitAutorhythmic Cells = Pace-Maker Cells: special self-excitable cardiac muscle cellsFunction: stimulates heart contraction8. Long Absolute Refractory Period Function: to prevent tetany

Desmosomes

Gap junctions

Intercalated discs

Slide32

III. Heart PhysiologyA. Mechanism and Events of Contraction

1.

*Review of Skeletal Muscle Cells*Depolarization-via APProceeds down T tubulesCausing SR to release Ca+2*Repolarization occurs while*Excitation-Contraction Coupling occursCa+2 attaches to TroponinMyosin Cross-bridges formThin Myofilament slides inwardSarcomeres shorten Cells shorten  Muscle shortens*Na+-K+ pump redistributes ions & SR reabsorbs Ca+2

Slide33

Skeletal

Fibers

Cardiac Cells

Muscle Tension

Have gap junctions between cells (intercalated discs)

Source of Ca+2: mostly extracellular through Ca+2 channels which then stimulate SR to release Ca+2Supply of ATP: Aerobic Respiration onlyNo TetanyHave Pace-Maker cells which initiate the contraction cycleCells contract together as a unit

2. Differences between skeletal and cardiac muscle contraction physiology– Cardiac cells have:

Slide34

3. Mechanism and Events of Cardiac Cell Contraction

a. Stimulus: comes from Autorhythmic Cells  Pacemaker Potentialb. Action Potential– initiated by Pacemaker Potentialc. Depolarization in Cardiac Muscle Cells 1 in figurei) Na+ channels openii) slow Ca2+ channels open  iii) Influx of extracellular Ca2+ causes Depolarization

Na

+

Slow Ca

2+

Ca

2

+

Slide35

d. Excitation- Contraction coupling

3

Figure 18.12

AP in Cardiac Muscle Cells

Cardiac Muscle

/

Contraction

2

i

n figure

iv) Contraction begins as Ca+2 attaches to Troponin …v) Plateau Phase Ca+ channels slowly begin to closeContraction K+ channels closede. RepolarizationCa channels closeK+ channels openCa+ pumped back to SR and extracellular Muscle Contraction ends

3

in figure

Slide36

d. Excitation- Contraction coupling …

3

Figure 18.12

AP in Cardiac Muscle Cells

Cardiac Muscle

/

Contraction

f. Hyperpolarization–

NOg. Na-K+ Pump redistributes ions and SR reuptake Ca+2

Slide37

III. Heart Physiology …

B. Electrical Pathway: 1. Setting the Basic Rhythuma. Not Dependent on: Nervesb. Intrinsic Conduction System= Autorhythmic Cells: Non-Contractile & all linked togetherIn SA node, these cells have an unstable resting potential due to leaking in of Na+Functions: i) Initiate & Distribute Electrical Impulsesii) Coordinate and Synchronize Cardiac contractions

SA Node

AV Node

Slide38

2. Sequence of Excitation

i) Sinoatrial (SA) node– Function: initiate contraction causing Atria to contract firstLocation: superior Right AtriumIntrinsic Rate: 100 = too fast: so vagus nerve slows it down to Normal 75 beats/min = Sinus Rhythm Moves to: AV nodeAtrioventricular (AV) node– functions: autorythmic cells are slow (0.1 s) to respond so Atria finish contractingLocation: Interatrial septum, inferiorly and just above Tricuspid Valve

Slide39

2. Sequence of Excitation …

iii) Atrioventricular Bundle = AV bundle (bundle of His) Location: Very short in: Interventricular Septumiv) Bundle branches: carry impulses what direction: to bottom of Ventricles at ApexPurkinje fibers: Location: At apex and into Ventricular cardiac cellsFunction: Delivers electrical stimulations to ventricles which results in their contraction

Slide40

(a) Anatomy of the intrinsic conduction system showing the

sequence of electrical excitation

Internodal pathway

Superior vena cava

Right atrium

Left atrium

Purkinje

fibers

Inter-

ventricular

septum

1

sinoatrial (SA)

node

(pacemaker)

generates impulses.

2

Impulses

pause (0.1 s) at

atrioventricular

(AV) node.

atrioventricular

(AV) bundle

connects atria

to ventricles.

4

bundle branches

conduct impulses thru

interventricular septum.

3

Purkinje fibers

depolarize contractile

cells of both ventricles.

5

Action potential succession during one heartbeat.

Slide41

A. Electrical Events …5. Electrocardiography

= Picks up: Electrical activity of contractile & non-contractile cardiac cellsi) Electrodes, Leads: pick up electrical activityClinically: 12 leadsii) Electrocardiogram, ECG or EKG = 3-Lead: voltage difference between 2 points Vertical axis = voltage amplitudeHorizontal axis = Time

Figure 18.6

Electrocardiogram

P

=

QRS

=

T

=

Slide42

An electrocardiogram (ECG a.k.a. EKG) tracing

Sinoatrial

node

Atrioventricular

node

Atrial

depolarization

QRS complex

Ventricular

depolarization

Ventricularrepolarization

P-Q

Interval

S-TSegment

Q-TInterval

0.1

Atria Contracting

Ventricles Contracting

Slide43

4

5

6

Ventricular depolarization is

complete.

Ventricular repolarization

begins

at apex, causing the

T

wave.

Ventricular repolarization is

complete.

P

R

T

Q

S

P

R

T

Q

S

P

R

T

Q

S

Depolarization

Repolarization

Sequence of deflection waves of an ECG tracing

Slide44

1

Atrial depolarization

, initiated by

the SA node, causes the

P wave

.

P

R

T

Q

S

SA node

AV node

2

3

With atrial depolarization complete,

the impulse is

delayed at the AV node

.

Ventricular depolarization beginsat apex, causing the QRS complex.Atrial repolarization occurs.

P

R

T

Q

S

P

R

T

Q

S

Depolarization

Repolarization

Electrocardiography

…

Waves & Intervals– sequence of

Slide45

C. Heart Sounds: Valves Students do

Tricuspid valve

sounds typically

heard in right sternal margin of

5th intercostal space

Aortic valve

sounds heard

in 2nd intercostal space at

right sternal margin

Pulmonary valve

sounds heard in 2ndintercostal space at leftsternal margin

Mitral valve soundsheard over heart apex(in 5th intercostal space)in line with middle ofclavicle

K

now:

Heart

M

urmur

Incompetent

Stenotic