Heart

THE HEART IS TWO PUMPS: LEFT AND RIGHT

LEFT PUMP:From lungs to bodyRIGHT PUMP: From body to lungs

2

The Pulmonary and Systemic Circuits

Figure 18.13

Heart Chambers• Each pump has two types of chambers:

ATRIUM and VENTRICLE

Left Atrium

Left Ventricle

Right Atrium

Right Ventricle

4

Blood Flow• Deoxygenated blood from body enters

the RA through the superior and inferior vena cava.

• It pours through the TRICUSPID (RIGHT AV) VALVE into the right ventricle.

• Right atrium contracts, pushes blood into the right ventricle ventricle expands, then contracts with force.

• To prevent the blood from going back up into the atrium, need a valve.

5

Blood Flow• Blood comes from the superior or inferior vena cava, into the right

atrium, past the tricuspid valve, into the right ventricle. It then goes past the pulmonary semilunar valve, and into the pulmonary arteries.

IVC

Pulmonary arteriesSVC

RA

RV

Tricuspid valve

Pulmonary Semilunar valve

6

VALVES

• Valves are like a swinging door that can only open one direction. But you can push against this door, since it’s only tissue.

• But if you tie a rope to the doorknob, it won’t be able to go the wrong way. The ropes are called CHORDAE TENDONAE, (“heart strings”) which are anchored to pieces of myocardium called PAPILLARY MUSCLES.

• The contraction of the papillary muscles pulls on the chordae tendonae to close the valves, preventing a PROLAPSED VALVE (turned inside out).

7

Figure 18.9a

Valves

8

Function of the Atrioventricular Valves

Figure 18.9b9

Heart Valves – Valve Structure

Figure 18.8a10

Trabeculae carneae (spongy meat)

• Trabeculae carnae are masses of irregular spongy tissues which project from the inner surface of the right and left ventricles.

• The purpose of the trabeculae carneae is to prevent suction that would occur with a flat surface and thus impair the heart's ability to pump efficiently.

• The trabeculae carneae also serve a similar function to papillary muscles in that their contraction pulls on the chordae tendineae, preventing prolapsed mitral (bicuspid) and tricuspid valves.

11

Trabecula Carnae

12

What is an artery?

• An artery is a vessel that carries blood AWAY from the heart. It does not matter if it is oxygenated or deoxygenated blood.

• A vein is a vessel that carries blood TOWARD the heart. It does not matter if it is oxygenated or deoxygenated blood.

13

Blood FlowWith the ventricular contraction, blood can go only one way: into the PULMONARY ARTERY (one of the few arteries with deoxy blood). When the ventricles relax, the PULMONARY SEMILUNAR VALVE closes to prevent blood from going from the pulmonary artery back into the right ventricle.

IVC

Pulmonary arteries

Pulmonary veins

SVC

RA

RV

Tricuspid valve

Pulmonary semilunar valve

14

Function of the Semilunar Valves

Figure 18.10a, b15

Blood Flow

• When the ventricles relax, the PULMONARY SEMILUNAR VALVE closes to prevent blood from going from the pulmonary artery back into the right ventricle.

• Do the semilunar valves have a chordae tendonae?

• No; the blood is not being forced back (with a contraction), it just falls back with gravity, so there’s not as much pressure.

16

Blood Flow• Blood then goes into lungs, gets oxygenated, and returns on the left

side through the PULMONARY VEINS (one of the few veins with oxy blood), into the LEFT ATRIUM.

LA

LV

Pulmonary arteries

Pulmonary veins

Tricuspid valveBicuspid (mitral) valve

17

Lungs

Blood FlowFrom the LEFT ATRIUM, it goes through the MITRAL VALVE (BICUSPID VALVE) into the LEFT VENTRICLE(there are also chordae tendonae here), which contracts. Therefore, the left ventricle is the chamber which is responsible for generating the largest pressure upon contraction.

LA

LV

Pulmonary arteries

Pulmonary veins

Tricuspid valveBicuspid (mitral) valve

18

Lungs

Mitral Valve

• The mitral valve gets its name from being the shape of a Bishop’s hat, called a mitre.

19

Blood Flow• The blood then goes past the AORTIC SEMILUNAR VALVE, into

the AORTA, and out to the body.

20

LA

LV

IVC

Pulmonary arteries

Aorta

Pulmonary veins

SVC

RA

RV

Tricuspid valveBicuspid valve

Pulmonary semilunar valve

The semilunar valves are located between the ventricles and the great arteries.

21

VALVES: “Try before you Buy”

• TRICUSPID VALVE• BICUSPID VALVE (MITRAL VALVE) • PULMONARY SEMILUNAR VALVE • AORTIC SEMILUNAR VALVE

• Structures associated with tricuspid and bicuspid valves– CHORDAE TENDONAE– PAPILLARY MUSCLES

22

Blood FlowDeoxy blood sup/inf vena cava R atrium tricuspid valve R ventricle pulmonary semilunar valve pulmonary artery lungs pulmonary veins Left atrium mitral (bicuspid) valve Left ventricle aortic semilunar valve aorta rest of body.

23

LA

LVIVC

Pulmonary arteries

Aorta

Pulmonary veins

SVC

RA

RV

Tricuspid valveBicuspid valve

Pulmonary semilunar valve

Aortic semilunar valve

STRUCTURES TO KNOW ON THE SHEEP HEART • A. myocardium• B. endocardium• C. visceral pericardium  • 1. apex • 2. interventricular septum (IV septum)• 3. left ventricle • 4. right ventricle • 5. right atrium • 6. left atrium • 7. chordae tendinae • 8. papillary muscles • 9. tricuspid valve • 10. bicuspid (mitral) valve • 11. trabeculae carni• 12. aortic semilunar valve

Apex

Myocardium (meaty areas of brown muscle

Endocardium (inside all chambers where blood touches)

Visceral pericardium (outer shiny surface of heart)

What LAYER of tissue is this?

Apex

What CHAMBER is this? Right ventricle

What CHAMBER is this? Right atrium

What CHAMBER is this? Left atrium

What CHAMBER is this? Left ventricle

Apex

Atrial septum

Interventricular Interventricular septumseptum

Mitral (bicuspid) valve

Apex

Tricuspid valve

Mitral Mitral (bicuspid) (bicuspid) valvevalve

Cordae Cordae tendonaetendonae

Papillary Papillary musclesmuscles

Aortic Aortic semilunar semilunar

valvevalve

Trabeculae Trabeculae carnaecarnae

Aorta

Superior vena cava

Pulmonary artery

STRUCTURES TO KNOW ON THE HUMAN HEART

• A. myocardium• B. endocardium• C. visceral pericardium • D. pulmonary trunk• E. pulmonary veins (there are four) • F. pulmonary arteries • G. right coronary artery • H. left coronary artery • I. Circumflex artery• J. posterior interventricular artery • K. anterior interventricular artery

L. Right brachiocephalicM. Right subclavianN. Right common carotidO. Left common carotidP. Left subclavian

Visceral pericardium (outer shiny surface)

Myocardium

Endocardium

STRUCTURES TO KNOW ON THE HUMAN HEART • 1. apex • 2. Interventricular septum (IV septum)• 3. left ventricle • 4. right ventricle • 5. right atrium • 6. left atrium • 7. atrial septum • 8. chordae tendinae • 9. papillary muscles • 10. trabeculae carni• 11. mitral valve (bicuspid valve) • 12. tricuspid valve • 13. aortic semilunar valve• 14. pulmonary semilunar valve • 15. aorta • 16. superior vena cava • 17. inferior vena cava

Pulmonary trunk

Left coronary artery

Right coronary

artery

Superior vena cavae

Aorta

Right Atrium

Left Atrium

L. Pulmonary artery

Apex

Right Auricle (ear shaped)

Posterior view of heart

Superior vena cavae

Inferior vena cavae

Trachea

Aorta

Right Atrium

Left Atrium

Pulmonary veins

Pulmonary veins

Posterior interventricular artery

Coronary sinus

Anterior interventricular artery

Left Atrium

Left Ventricle

Interventricular septum

Right Atrium

Right Ventricle

Atrial septum

Right Auricle (ear shaped)

Pulmonary semilunar valve

Papillary muscles

Cordae tendonae

Trabeculae carnae

Mitral (bicuspid) valve

Tricuspid valveAortic semilunar valve (look deep under here)

Look up here to see aortic semilunar valve

Pulmonary semilunar valve

R. Coronary artery

Pulmonary veins

L. Coronary artery

Anterior interventricular artery

Circumflex artery

Aorta

Pulmonary trunk

Left subclavian artery

Left common carotid artery

R. Brachiocephalic artery

R. common carotid artery

L. Pulmonary artery

R. subclavian artery

Superior vena cava

Trachea

EsophagusInferior vena cava

Fetal Circulation

FETAL CIRCULATION

• Umbilical vein carries oxygenated blood from the placenta; it is the VESSEL where blood is most highly oxygenated.

• Right atrium is the CHAMBER where blood is most highly oxygenated

• Foramen ovale is the hole between the fetal atria

• Ductus arteriosus is the connection between the pulmonary artery and the aorta

Fetal Circulation