Cardiovascular Flashcards
Where does the exchange of nutrients and waste happen?
Capillaries
What are the boundaries of the mediastinum?
Anterior: sternum
Posterior: bodies of thoracic vertebrae
Lateral: right and left pleural cavities
What are the divisions of the mediastinum?
Superior and inferior.
Inferior is further divided into anterior, middle and posterior.
What are the layers of the heart?
The epicardium, myocardium and endocardium
What is the pericardium divided into?
Fibrous pericardium and serous pericardium.
Serous pericardium:
- Parietal pericardium: lines interior of fibrous pericardium
- Visceral pericardium (epicardium): continues over the surface of the heart
What are the four heart chambers?
2 atria and 2 ventricles
Where does the right atrium receive blood from?
Superior and inferior vena cava and coronary sinus
Where does the left atrium receive blood from?
The four pulmonary veins
Which part of the atria is rough and why?
The anterior walls of the aria are rough because of the pectinate muscle.
Where is the fossa ovalis located?
The interatrial septum
What separates the two ventricles?
Interventricular septum
What does the inner surface of both ventricles contain?
Trabecular carinae
What are the cardiac valves?
Tricuspid, mitral, pulmonary and aortic
How are the AV valves attached?
Their flaps attach to chord tendinae which is connected to the papillary muscle.
What is the function of the semilunar valves?
To guard the bases of the two large arteries leaving the ventricular chambers.
What is the fibrous skeleton?
Dense connective tissue that surrounds the valves of the heart and merges with their interventricular septum
What is the function of the coronary arteries?
To supply blood to the myocardium
What does the left coronary artery divide into?
The left anterior descending (LAD) and the circumflex branch
Where is the LAD located and what is its function?
It is in the anterior interventricular sulcus and it supplies oxygenated blood to the walls of both ventricles
Where is the circumflex branch located and what is its function?
It lies in the coronary sulcus and it distributes oxygenated blood to the walls of the left atrium and ventricle
Where does the right atrium supply to?
Small atrial branches, the posterior interventricular and marginal branch.
Where is the posterior interventricular located?
It follows the posterior interventricular sulcus
What does the posterior interventricular artery supply?
It supplies the walls of the two ventricles with oxygenated blood
Where is the marginal branch located? Where does it supply blood?
It is beyond the coronary sulcus and runs along the right margin
Lateral side of right ventricle
What does the marginal branch supply?
It transports oxygenated blood to the wall of the right ventricle
What is coronary anastomosis?
Both coronary arteries anastomose with each other to form a loop so that there is an ensured alternate pathway of blood
What is the coronary sinus?
It is where most of the deoxygenated blood from the myocardium drains into and it empties into the right atrium
Which are the coronary veins?
The great cardiac vein
Middle cardiac vein
Small cardiac vein
Anterior cardiac veins
Great Cardiac Vein
Anterior IV sulcus and drains the areas of the heart supplied by the left coronary artery (left atrium and left ventricle)
Middle Cardiac Vein
Posterior IV sulcus and it drains the areas supplied by the posterior IV branch of the right coronary artery (both ventricles)
Small Cardiac Vein
Drains the right atrium and right ventricle
Anterior Cardiac Vein
Drains right ventricle and opens into right atrium
What are the three layers of the arteries?
Tunica intima: inner epithelium
Tunica media: thick smooth layer
Tunica externa: outer connective tissue
What changes in the structure of the tunica media with the size of the artery?
With larger arteries, there is more elastic tissue, and less smooth muscle for stretching and better absorption of blood
What is the main layer in arterioles?
Tunica media
What is peripheral resistance?
The regulation of blood pressure by controlling the diameter size of arterioles, the pressure the blood encounters when passing through the vessels.
What controls the entry to the capillary beds?
Precapillary sphincters which are rings of smooth muscles which control blood flow
What are the types of true capillaries?
Continuous capillaries: CNS, lungs, muscle tissue, and skin
Fenestrated capillaries: kidneys, small intestine, choroid plexuses, ciliary processes, and endocrine glands
Sinusoids: red bone marrow, spleen, anterior pituitary, parathyroid, and adrenal glands
What is the blood-brain barrier ?
Capillaries make up the BBB, it limits the ability of toxins and many medications to pass into the brain
What helps keep the BBB?
Tight junctions
Which layer of the veins is thicker?
The tunica externa
What is the vascular sinus?
It has no smooth muscle in order to alter its diameter.
The aorta and its branches?
Ascending
Arch
Thoracic
Right and left coronary arteries
Brachiocephalic trunk
Left common carotid
Left subclavian
Bronchial
Oesophageal
Posterior intercostal
Superior phrenic
Mediastinal
Pericardial
What is the circle of Willis?
The arteries in the brain which transport blood to the different organs and sections
Where does the circle of Willis originate from?
Two vertebral arteries join to form the basilar
Two internal carotid arteries
What is portal circulation?
Special type of vascular network connecting one capillary network into another through the portal vein.
What are the two types of portal circulation?
Hypophyseal portal system
Hepatic portal system: stomach and intestine to the liver
How do cardiac muscle fibers connect?
Through intercalated discs, desmosomes, and gap junctions.
What is the function of the gap junctions?
To allow the whole myocardium of the atria/ ventricles to contract as a single and coordinated unit
What is the cardiac conductive system?
It consists of auto-rhythmic fibers which are modified cardiomyocytes that generate action potentials that trigger heart contractions.
What do issues with the autorhythmic fibers lead to?
Arrhythmias
What are the functions of the cardiac conductive system?
To continue to generate and deliver regular impulses to cardiac muscle
To form the conduction system to ensure that cardiac chambers contract in a coordinated manner
What helps the heart be an effective pump?
Gap junctions and fibrous skeleton
What are the functions of the fibrous skeleton?
For structural foundation for valves
Prevents overstretching of valves
Serves as point of insertion for bundles
Electrical insulator between the chambers
What happens when the pacemaker potential reaches threshold?
It triggers an action potential (SA node)
Why does the SA node serve as a natural pacemaker?
Due to its fast discharge
Operation of Cardiac Conductive System
- SA node starts off each heartbeat
- Impulse from the SA node propagates through atria via gap junctions in the intercalated discs of atrial muscle fibers
- Atria contract
- Impulse spreads through the atria to the AV node
- At the AV node, the impulse is slightly delayed
- Impulse travels through AV bundle, bundle branches, and Purkinje fibers
- Ventricles contract