The Heart Flashcards
Arteries carry blood ____ the heart
away from
veins carry blood ______ the heart
back to
What are the great vessels?
the arteries and veins entering and leaving the heart
Where do the two side-by-side pumps of the heart pump blood to?
- one pump directs blood to the lungs
- one pump directs blood to most body tissues
How is blood pressure generated?
contraction and relaxation of heart walls
What is blood pressure?
the force of the blood pushing against the inside walls of blood vessels
What does the pulmonary circulation consist of?
right side of the heart and the pulmonary arteries and veins
Where does the pulmonary circulation move blood?
to the lungs and back to the left side of the heart
What does the systemic circulation consist of?
left side of the heart and arteries and veins
Where does the systemic circulation move blood?
to most body tissues and back to the right side of the heart
Where is the position of the heart?
Slightly left of midline deep to the sternum in a compartment of the thorax known as the mediastinum
What is the posterosuperior surface of the heart mainly composed of, and what is this surface called?
- mainly left atrium
- base
What is the superior border formed by?
- great arterial vessels
- superior vena cava
What is the inferior conical end of the heart called?
apex
What is the inferior border formed by?
the right ventricle
The heart is enclosed within a tough sac called the _______.
pericardium
Name and describe the two parts of the pericardium.
- fibrous pericardium: tough outer sac
- serous pericardium: composed of parietal and visceral layers; forms pericardial cavity
What are the 3 layers of the heart wall, from superficial to deep?
- epicardium
- myocardium
- endocardium
Describe the epicardium.
consists of the visceral layer of the serous pericardium and areolar connective tissue
Describe the myocardium.
- cardiac muscle
- thickest of the 3 layers
Describe the endocardium.
internal surface of the heart chambers and external surface of the heart valves
The anteroinferior borders of the atria form a muscular extension called the _____.
auricle
What is the coronary sulcus?
a groove that separates the atria and ventricles
What are the 4 chambers of the heart?
- right atrium
- right ventricle
- left atrium
- left ventricle
Name the 4 valves of the heart.
- right atrioventricular
- pulmonary semilunar
- left atrioventricular
- aortic semilunar
Where does the right atrium receive venous blood from?
- the heart
- the muscles
- systemic circulation
Name the 3 veins that drain into the right atrium.
- superior vena cava
- inferior vena cava
- coronary sinus
What separates the right atrium from the right ventricle?
right atrioventricular valve (tricuspid valve)
When is the right AV valve forced closed?
when the right ventricle begins to contract (prevents back flow)
What is the name of the thick wall that separates the right and left ventricles?
interventricular septum
What is the trabeculae carneae?
large, irregular muscular ridges on inner walls of ventricles
What do the papillary muscles of the right ventricle do?
anchor chordae tendineae attached to the right AV valve cusps
What are atrioventricular valve cusps?
triangular flaps that hang down into the ventricle
What is the function of the chordae tendineae?
prevent the cusps from flipping into the right atrium when the right ventricle contracts
What is the smooth area at the superior end or roof of the ventricle called?
conus arteriosus
What separates the right ventricle and the pulmonary trunk?
pulmonary semilunar valve
What separates the left atrium and the left ventricle?
left atrioventricular valve (bicuspid, mitral valve)
When is the left AV valve forced closed?
When the left ventricle contracts
What separates the left ventricle and the aorta?
aortic semilunar valve
Which ventricle has a thicker wall?
left is 3x thicker than right
Describe the right and left coronary arteries.
- travel within the coronary sulcus
- supply the heart wall muscle with oxygen and nutrients
Why does the heart contract as a single unit?
all connected with gap junctions
What are gap junctions made up of?
intercalated discs
What is autorhythmicity?
capable of initiating its own heartbeat independent of external nerves
What is the sinoatrial (SA) node or the pacemaker, and where is it located?
- special cardiac muscle cells that initiates autorhythmicity
- right atrium next to SVC
Describe the path that an impulse takes in the heart.
- via gap junctions to left atrium and the atrioventricular (AV) node located in the floor of the right atrium
- AV bundle or bundle of His, which extends into the interventricular septum
- AV bundle divides into left and right bundles
- purkinje fibres that begin at the apex of the heart and spread the impulse superiorly to all of the ventricular myocardium
What innervates the heart?
- sympathetic (ANS)
- parasympathetic (ANS)
What does the autonomic nervous system do?
does not initiate a heartbeat, but can increase or decrease the rate of the heartbeat
What is the cardiac cycle?
the time from the start of one heartbeat to the initiation of the next
What is systole?
contraction of a chamber
What is diastole?
relaxation of a chamber
Describe the blood flow through the heart.
- superior and inferior vena cava
- right atrium
- right atrioventricular valve
- right ventricle
- pulmonary semilunar valve
- pulmonary trunk and arteries
- gas exchange in the lungs
- pulmonary veins
- left atrium
- left atrioventricular valve
- left ventricle
- aortic semilunar valve
- aorta
- systemic arteries
- gas and nutrient exchange in peripheral tissues
- systemic veins
