Lab Three - Exercise 27: Structure of the Heart

arteries

vessels that carry blood from the heart

veins

return blood to the heart

coronary arteries

carry blood from the heart, but they carry the blood to the heart muscle

cardiac veins

take blood from the heart muscle back to the heart for recirculation

mediastinum

contains the heart, the coverings of the heart (the pericardia), and other structures, such as the esophagus and descending aorta

what is the first structure you find when opening the chest cavity, made of tough, outer connective tissue?

fibrous pericardium - encloses the heart

what lining is deep to the fibrous pericardium?

parietal pericardium (outer layer of the serous pericardium)

what is deep to the parietal pericardium?

pericardial cavity; which contains a small amount of serous pericardial fluid

serous pericardial fluid

reduces the friction between the outer surface of the heart and the parietal pericardium

what layer is closest to the heart (inner layer of the serous pericardium)?

visceral pericardium (epicardium)

what is the outermost layer of the heart wall?

epicardium - composed of epithelial and connective tissue

what is the middle layer of the heart wall?

myocardium; thickest of the three layers; mostly made of cardiac muscle

how is cardiac muscle arranged in the heart?

spirally; providing a more efficient wringing motion to the heart

endocardium

inner layer of the heart wall; serous membrane that consists of endothelium (simple squamous epithelium) and connective tissue

where does blood enter the heart?

right atrium - which flows into the right ventricle

From the right ventricle, where does the contraction send the blood?

to the lungs

once being oxygenated in the lungs, where does the blood reenter the heart?

left atrium

where does blood move from the left atrium?

left ventricle; which pumps it to the rest of the body

where are the apex and base of the heart?

pointed end is the apex and the base is where the great vessels leave the heart - the base is actually on top of the apex!

what delineates the right ventricle from the left ventricle?

ventricular sulcus (groove)

what’s found in the ventricular sulcus?

coronary arteries and cardiac veins

which wall of the heart is thicker?

left ventricle

auricles

earlike flaps on the anterior, superior region of the heart

atrioventricular sulcus (groove)

junction of the right atrium and right ventricle

coronary sinus

large venous chamber that carries blood from the cardiac veins to the right atrium

what do the superior and inferior vena cavas do?

return blood to the right atrium

pulmonary veins

carry blood from the lungs to the left atrium

what arteries does the left coronary artery (rooted in the ascending aorta) branch into?

anterior interventricular artery and the circumflex artery

what arteries does the right coronary artery (rooted in the ascending aorta) branch into?

posterior interventricular artery and right marginal artery

when do arteries fill with blood?

ventricular relaxation

where does the great cardiac vein feed into?

cardiac sinus

where does the small cardiac vein feed into?

coronary sinus

where does the coronary sinus empty into?

right atrium

what are the ventricles separated by?

interventricular septum; which forms a wall between the two ventricular chambers

what is the medial wall of the atrium called?

interatrial septum

fossa ovalis

thin, oval depression in the atrial wall

what is the fossa ovalis called in fetal hearts?

foramen ovale

what do pectinate muscles do?

provide additional strength to the atrial wall

tricuspid valve

prevents the return flow of blood from the right ventricle into the right atrium during ventricular contraction

what are the thin, threadlike attachments of the tricuspid valve called?

chordae tindinea; which are attached to larger papillary muscles, which are extensions from the wall of the ventricle

trabeculae carnea

small extensions of the right ventricle that strengthen the ventricle wall

where does blood from the right ventricle flow into?

the pulmonary trunk toward the lungs

pulmonary semilunar valve

appears as three small cusps between the right ventricle and the pulmonary and keeps blood flowing in reverse from the pulmonary trunk into the right ventricle during ventricular relaxation

where does blood from the pulmonary trunk flow to?

pulmonary artieries before entering the lungs

what does blood in the lungs do?

releases carbon dioxide and picks up oxygen

where do the pulmonary veins carry the blood from the lungs?

into the left atrium

where are the pulmonary veins located?

in the superior, posterior portion of the left atrium

where is the bicuspid valve found?

between the left atrium and left ventricle

what is the bicuspid valve also known as?

mitral valve or left atrioventricular valve

what does the bicuspid valve also have?

attached chordae tendineae and papillary muscles

where is the aortic semilunar valve located?

the junction of the left ventricle and the ascending aorta; prevents blood from the aorta into the left ventricle

where does blood from the left ventricle go?

into the aorta and the rest of the body

what are the differences between the human heart and sheep heart?

position of the superior and inferior venae cava

The heart is located between the lungs in an area known as the ______________ .

Mediastinum

What is the name of the layer that is superficial to the pericardial cavity?

Parietal pericardium

What is the innermost layer of the heart called?

Endocardium

Is the apex of the heart superior or inferior to the rest of the heart?

Inferior

What is the name of the depression between the two ventricles on the anterior surface of the heart?

Interventricular groove

Are auricles extensions of the atria or the ventricles?

Atria

What three vessels take blood to the right atrium?

Superior vena cava, inferior vena cava, coronary veins

Where do the great cardiac vein and the small cardiac vein take blood?

Coronary sinus

What blood vessels nourish the heart tissue?

Coronary arteries

What structure separates the left atrium from the right atrium?

Interatrial septum

What is the name of the thin spot between the atria?

1. Since fetuses do not need oxygen, allows blood to flow directly from right atrium to left atrium without going to the lungs

Fossa ovalis

The bicuspid valve is located between what two chambers of the heart?

Left atrium and left ventricle

Name the structure between the atrioventricular valve and the papillary muscle

Chordae tendinae

What is the function of the aortic semilunar valve?

Prevents back flow of blood

What is another name for the tricuspid valve?

Right atrioventricular valve

What cell type makes up most of the myocardium?

Myocytes

What adaptation do you see in the walls of the left ventricle being thicker than those of the right ventricle?

Pushes blood through the body, so it needs to be thicker and stroner

How does cardiac muscle resemble skeletal muscle?

Striations

In terms of function, how is cardiac muscle different from skeletal muscle?

Contracts independently from nervous impulses

Superior vena cava

Right atrium

Right ventricle

Aortic arch

Base of heart

Pulmonary trunk

Left atrium

Left ventricle

Apex

Name the structures surrounding the heart, starting with the heart and moving outward.

Heart ---> visceral pericardium ---> pericardial cavity

---> parietal pericardium ---> fibrous pericardium

Epicardium (visceral pericardium)

Myocardium

Endocardium

Trabeculae carneae

Aortic semilunar valve

Pulmonary semilunar valve

Tricuspid valve

Pulmonary arteries

Pulmonary veins

Bicuspid valve

Interventricular septum

Body ---> travels back to heart in veins ---> enters right atrium via superior vena cava, inferior vena cava, or coronary sinus ---> through tricuspid valve to right ventricle ---> through pulmonary semilunar valve out of pulmonary trunk ---> pulmonary arteries take blood to the lungs

Flow of deoxygenated blood

Lungs ---> oxygenated in pulmonary capillaries ---> goes back to heart via pulmonary veins ---> enters left atrium ---> through bicuspid valve to left ventricle ---> through aortic semilunar valve ---> up and out of aorta

Flow of oxygenated blood

Coronary sulcus

Papillary muscles