Circulatory System (Hearts) Flashcards
What is the function of the circulatory system? (2)
- distributes oxygen and nutrients to entire body
- picks up waste materials by cells to be eliminated by other systems (respiratory, urinary systems)
What does the circulatory system include?
heart and blood vessels
What is the mediastinum bounded by?
bounded anteriorly by sternum and costal cartilages, laterally by lungs, and posteriorly by bodies of thoracic vertebrae
What does the mediastinum contain?
heart and its large vessels
esophagus
trachea
thoracic aorta
What are the 2 parts of the mediastinum?
What are they divided by?
superior and inferior parts
divided by transverse imaginary plane passing through sternal angle anteriorly, and intervertebral disc between vertebrae TIV and TV posteriorly
What are the 3 parts of the inferior mediastinum?
middle mediastinum
anterior mediastinum
posterior mediastinum
Inferior Mediastinum
What does the middle mediastinum contain?
- heart and its pericardium (membrane)
- ascending aorta, pulmonary trunk, and pulmonary veins
- right and left phrenic nerves
main bronchi
Inferior Mediastinum
Where is the anterior mediastinum?
between sternum and pericardium
Inferior Mediastinum
What does the anterior mediastinum contain?
thymus gland
Inferior Mediastinum
Where is the posterior mediastinum?
between pericardium, and bodies of vertebrae TV-TXII
Inferior Mediastinum
What does the posterior mediastinum contain?
- descending aorta, azygus, and hemiazygus veins
- right and left vagus nerves
- sympathetic chains (trunks) and splanchnic nerves
- thoracic duct and esophagus
What does the superior mediastinum contain?
- arch of aorta and its branches
- right and left brachiocephalic veins, inferior part of superior vena cava, and end of azygus vein
- right and left phrenic and vagus nerves
- trachea, esophagus, thymus gland, and thoracic duct
What is the heart?
muscular conical pump
Where is the heart located?
middle mediastinum
Describe the path of blood circulation from the body.
- right atrium receives deoxygenated blood from entire body, and passes it to right ventricle
- right ventricle pumps blood to lungs (pulmonary circuit)
- left atrium receives oxygenated blood from lungs, and passes it to left ventricle
- left ventricle pumps blood throughout body (systemic circuit)
Surface Anatomy of Heart
What are the 4 corners of the quadrangle that demarcates the heart image on the chest?
- upper left corner: in left 2nd intercostal space, 1 inch away from midline
- upper right corner: at right 3rd costal cartilage, 1 inch away from midline
- lower right corner: at right 6th costal cartilage, 1 inch away from midline
- lower left corner: in left 5th intercostal space, 3-4 inches away from midline
External Features of Heart
What are the 4 main external features?
- heart sulci
- heart surfaces
- heart base
- heart apex
External Features of Heart - Sulci
What are the 3 main sulci?
- coronary sulcus
- anterior interventricular sulcus
- posterior interventricular sulcus
External Features of Heart - Sulci
What does the coronary sulcus do?
encircles heart and separates atria from ventricles
External Features of Heart - Sulci
Where are the anterior and posterior interventricular sulci?
between ventricles on anterior and inferior surfaces
External Features of Heart - Surfaces
What are the 4 surfaces?
- anterior (sternocostal) surface
- inferior (diaphragmatic) surface
- left pulmonary surface
- right pulmonary surface
External Features of Heart - Surfaces
Where is the anterior (sternocostal) surface?
What does it consist of?
related to sternum and 2nd-6th costal cartilages
consists of right ventricle and parts of right atrium and left ventricle
External Features of Heart - Surfaces
Where is the inferior (diaphragmatic) surface?
What does it consist of?
leaning on diaphragm, has posterior interventricular sulcus
consists of left ventricle, and small part of right ventricle
External Features of Heart - Surfaces
Where is the left pulmonary surface?
What does it consist of?
related to left lungs
consists of left ventricle, and portion of left atrium
External Features of Heart - Surfaces
Where is the right pulmonary surface?
What does it consist of?
related to right lung
consists of right atrium
External Features of Heart - Base
What is the heart base formed by?
What direction does it face?
mainly formed by left atrium and small portion of right atrium
faces posteriorly
External Features of Heart - Apex
What is the heart apex formed by?
What direction does it face?
formed by left ventricle
directed inferiorly and left
Heart Chambers - Right Atrium
What does the right atrium receive venous blood from?
superior vena cava, inferior vena cava, and coronary sinus
Heart Chambers - Right Atrium
Where is the pectinate muscle?
lines anterior part of right atrium, and extends into right auricle (conical ear-like appendage)
Heart Chambers - Right Atrium
What is the fossa ovalis?
impression located on interatrial septum
remnant of embryonic foramen ovalis that used to connect right and left atrium
Heart Chambers - Right Atrium
How is the right atrium connected to the right ventricle?
via atrioventricular opening, guarded by atrioventricular (tricuspid) valve
Heart Chambers - Right Ventricle
What are traveculae carneae?
muscular ridges on walls of the ventricle
Heart Chambers - Right Ventricle
What are papillary muscles?
group of muscular ridges (3) that are finger-like projections that arise from walls of ventricle, and insert to leaflets of tricuspid valve via chordae tendineae (tendon-like structure)
Heart Chambers - Right Ventricle
What does the pulmonary artery arise from?
superior part of right ventricle
Heart Chambers - Right Ventricle
What is the pulmonary valve?
semilunar valve located at beginning of artery that prevents blood from flowing back to right ventricle
Heart Chambers - Right Ventricle
How is the right ventricle separated from the left ventricle?
by interventricular septum
Heart Chambers - Left Atrium
What type of blood does the left atrium receive, and from where?
receives oxygenated venous blood from right and left pulmonary veins
Heart Chambers - Left Atrium
Where are pectinate muscles?
only found in left auricle (ear-like appendage)
Heart Chambers - Left Atrium
What is the left atrium connected to the left ventricle by?
via left atrioventricular opening, guarded by left atrioventricular (bicuspid or mitral) valve
Heart Chambers - Left Ventricle
Describe the structure of the trabeculae carneae, papillary muscles (2), and chordae tendinae?
similar to right ventricle
Heart Chambers - Left Ventricle
What does the aorta arise from?
superior part of left ventricle
Heart Chambers - Left Ventricle
What is the aortic valve?
What is its function?
semilunar valve at beginning of aorta that prevents blood from flowing back to left ventricle
What is the heart surrounded by?
pericardial sac
What is the pericardial sac composed of? (2)
fibrous pericardium
serous pericardium
What is the fibrous pericardium?
What does it attach to?
(outer fibrous layer) thick layer of dense connective tissue surrounding the heart
attaches to central tendon of diaphragm inferiorly, and to great vessels of heart superiorly
What is the serous pericardium?
2 layers of connective tissues specialized in secretion of serous fluid
What are the 2 layers of the serous pericardium?
Where is each layer?
parietal layer: lines inner surface of fibrous pericardium
visceral layer (epicardium): attaches to surface of heart
What is the pericardial cavity?
What is it filled with?
narrow space between parietal and visceral layers (of the serous pericardium)
filled with small amount of serous fluid that lubricates the heart surfaces to facilitate heart movements
What does the conducting system of the heart do?
coordinates cardiac cycle
What does the conducting system of the heart consist of?
modified cardiac muscle fibers
What is the sinoatrial (SA) node?
Where is it located?
pacemaker of the heart located on right atrium wall close to superior vena cava opening
Where is the atrioventricular (AV) node?
located on right side of interatrial septum close to opening of coronary sinus
Where is the atrioventricular bundle (bundle of His)?
starts from AV node → enters interventricular septum → divides into right and left branches
What do the branches of the bundle of His give rise to?
Purkinje fibers that distribute into right and left ventricular walls
Describe the pathway of the electrical impulse.
SA node → propagates through and contracts atrial walls before reaching AV node → passes through ventricular walls via atrioventricular bundle and Purkinje fibers → ventricular contraction
What does the autonomic nervous system regulate?
regulates heart rate and its contraction force
Autonomic Nervous System
What do preganglionic sympathetic fibers arise from?
Where do they synapse?
What happens after they synapse?
lateral horns of T1-T5 spinal cord segments
synapse in cervical and upper thoracic paravertebral sympathetic ganglia
continue as postganglionic sympathetic fibers to contribute in formation of cardiac plexus under aortic arch
Autonomic Nervous System
What doe the sympathetic component of the cardiac plexus do?
increases heart rate
Autonomic Nervous System
What doe the parasympathetic component of the cardiac plexus do?
decreases heart rate
Autonomic Nervous System
What are preganglionic parasympathetic fibers derived from?
What do they contribute to?
vagus nerves
enter and contribute in cardiac plexus
Autonomic Nervous System
Where do preganglionic parasympathetic fibers synapse?
in ganglia located either within plexus or embedded in walls of atria
Autonomic Nervous System
What is the visceral afferent component of the cardiac plexus associated with?
vagus nerve and sympathetic fibers
Autonomic Nervous System
What do fibers associated with vagus nerve do? (2)
- detect changes in blood pressure and chemical contents (O2 and CO2)
- concerned with cardiac reflexes
Autonomic Nervous System
What do afferent fibers associated with sympathetic fibers do? (2)
conduct ‘pain’ sensation from heart
Autonomic Nervous System
Where do fibers associated with sympathetic fibers return?
return to cervical or upper thoracic ganglia of sympathetic chain (trunk) to end in upper 4-5 thoracic segments of spinal cord
