The heart

The heart is surrounded by a

pericardium, consisting of two parts:

– An outer _______ pericardium

– An inner ________ pericardium, which

consists of two layers

fibrous and serous

attached to

the surface of the heart

inner visceral layer(epicardium)

adjacent to the fibrous

pericardium

outer parietal layer

The space between the two

serous layers is called the

pericardial cavity, it contains

pericardial fluid

Epicardium

External surface, consists of visceral pericardium

Myocardium

Consists of cardiac tissue, including cardiac muscle cells, connective

tissue, blood vessels, and nerves

Endocardium

Internal, endothelial surface

Cardiac muscle cells contract

without information coming

from the

CNS (involuntary)

move directly from one cell to

another creating a direct, electrical

connection

Ions

The Cardiac Skeleton is where

each cardiac cell is wrapped in an elastic sheath and muscle layers is wrapped in a fibrous sheet

The base is

the superior border of the heart

The apex is

the inferior portion of the heart

The right border is

formed by only the right atrium

The inferior border is

formed by the right ventricle

Interatrial groove

separates the left and right atria

Coronary sulcus

separates the atria and the ventricles

Anterior interventricular sulcus

separates the left and right ventricles

Posterior interventricular sulcus

also separates the left and right

ventricles

The left and right atria

– Positioned superior to the coronary sulcus

– Both have thin walls

– Both contain an expandable anterior portion called an auricle

The left and right ventricles

– Positioned inferior to the coronary sulcus

– Both have thicker walls than the atria

▪ Left wall is thicker than the right wall

The Right Atrium Receives oxygen-poor venous

blood via

superior vena

cava, inferior vena cava, and

coronary sinus

which contains Contains pectinate muscles right or left atrium?

Right atrium

Blood enters the right ventricle

by passing through the

atrioventricular valve(tricuspid valve)

Blood leaves the right ventricle

by passing through the

pulmonary valve(pulmonary

semilunar valve)

The right AV valve is connected

to

papillary muscles via

chordae tendineae

Trabeculae carneae

Muscular ridges

Moderator band

Muscular band that

extends from the

interventricular septum

to the ventricular wall only found in the right ventricle

The Left Atrium Receives oxygenated blood

from the lungs via

the right and

left pulmonary veins

in the left atrium Blood passes through the left

atrioventricular valve(mitral

valve)

which has the thickest wall right or left ventricle?

left ventricle

Blood leaves the left

ventricle by passing through

the

aortic valve(aortic

semilunar valve)

Blood enters the

ascending aorta

Blood then travels to the

_______ and then

down the _________ and to all body parts

(systemic)

aortic arch and descending aorta

AV valve function during the

cardiac cycle

Papillary muscles relax, Due to pressure in the atria,

the valves open, and Blood flows from atria to

ventricle

When the ventricles

contract

pressure causes

the AV valves to close and

semilunar valves to open

– Atrial branches

– Right marginal branch

– Posterior interventricular

branch

Right coronary artery (RCA)

– Circumflex branch

– Left marginal branch

– Anterior interventricular

branch

Left coronary artery (LCA)

Great cardiac vein

Delivers blood to the

coronary sinus

Middle cardiac vein

Delivers blood to the

coronary sinus

Coronary sinus

Drains directly into the

posterior aspect of the right

atrium

Which layer of the heart wall contains the cardiac muscle cells, connective tissues, and blood vessels?

Myocardium

The intercalated discs of cardiac muscle tissue contain gap junctions. What is the primary function of these gap junctions?

to allow ions to move between cells for a direct eletrical connection

What are the two circuits the heart pumps blood into?

1. Pulmonary circuit 2. Systemic circuit

Arteries

Transport blood away from the heart.

Veins

Transport blood toward the heart

Capillaries

Vessels that interconnect arteries and veins.

What are the four parts of every AV valve?

1. Ring of connective tissue. 2. Cusps. 3. Chordae tendineae. 4. Papillary muscles (contract to prevent valve inversion).

Describe the Left Ventricle and how it compares to the Right.

Thickest wall for strong contractions (systemic circuit).

• Does not have a moderator band.

• Left AV valve (bicuspid/mitral) has 2 cusps and 2 papillary muscles.

• Contraction is 6 to 7 times more powerful than the right ventricle.

Explain the function of AV valves during the Cardiac Cycle.

1. Papillar muscles relax. 2. Pressure in atria opens the valves; blood flows to ventricle. 3. Ventricles contract; pressure closes AV valves and opens semilunar valves. 4. Closure of AV valves prevents regurgitation (backflow) into atria.

Contraction is

systole

Atrial systole

Blood flows into the

ventricles

Ventricular systole

Blood is ejected into

the pulmonary trunk

and the ascending

aorta

Relaxation is

diastole(Chambers are filling with

blood)

Cardiac contractions of the cardiac

cycle are coordinated by

conducting

cells

Nodal cells(conducting cell)

Establish the rate of

contractions, SA and AV nodes

Conducting cells

Distribute the contractile

stimulus to the myocardium

Sinoatrial node (SA node)location and common name?

Located in the posterior wall of the right atrium near the entrance of

the superior vena cava, Also called the cardiac pacemaker

Bradycardia

slower-than-normal heart rate

Tachycardia

faster-than-normal heart rate

Atrioventricular node (AV node) location

Sits within the floor of the right atrium

Cardiac conducting system

1. Impulse travels from the SA node to the AV node

▪ Impulse conducted by internodal pathways

▪ Atrial contraction occurs

2. AV node slows impulse

3. Impulse travels from the AV node to the AV bundle

4. The AV bundle conducts impulse along the interventricular septum and

then divides to form the right and left bundle branches

▪ Serve right and left ventricle

5. The bundle branches conduct impulses to the Purkinje fibers

▪ Purkinje fibers connect to cardiac muscle cells

▪ Ventricular contraction occurs

Norepinephrine from the

sympathetic division of the

ANS causes:

An increase in the heart rate

An increase in the force of

contractions

Acetylcholine from the

parasympathetic division of the

ANS causes:

A decrease in the heart rate

decrease in the force of

contractions

Stimulation of

cardioacceleratory center:

activates sympathetic

neurons

Heart rate increases

Stimulation of cardioinhibitory

center

activates parasympathetic

neurons

Vagus (N X) is involved

Heart rate decreases

Which of the following statements

regarding the cardiovascular system

is TRUE?

When the heart beats, the atria contract first, followed by the

ventricles.

Which of the following vessels sends

blood to the lungs from the right

ventricle?

pulmonary artery

The myocardium _____.

consists of multiple, interlocking layers of cardiac muscle tissue

Which of the following contains the

fetal remnant of the foramen ovale?

right atrium

Which layer of the heart consists of

simple squamous epithelium tissue

that is continuous with the

endothelium of the attached greater

vessels?

endocardium

Which describes the inferior, pointed

tip of the heart that is formed mainly

by the left ventricle?

apex

Which of the following is the

function of the papillary muscles?

They prevent valve inversion into the atria.

Which of the following receives

deoxygenated blood from the

systemic circuit via the superior and

inferior vena cava?

right atrium