1. Overview and Anatomy Flashcards
Name the 4 functions of the CV system
o distributes dissolved gases & nutrients
o removes metabolic waste
o contributes to systemic homeostasis by controlling temp, O2 supply, pH, ionic composition, nutrient supply
o quickly adapts to changes in conditions and metabolic demands
What are the 3 parts to the CV system?
heart, blood, vasculature (including lymphatic sys)
How are the L and R heart connected?
They’re not
Describe pulmonary circulation.
low pressure, single pathway btw heart and lungs
Describe systemic circulation.
high pressure, multiple pathways from heart to vascular beds, arranged in parallel
Why is systemic circulation arranged in parallel?
To deliver oxygenated blood to only one organ before returing to the heart,
Which organ receives the majority of resting blood flow?
the brain
What are the 3 layers of the heart wall and what do they consist of?
o epicardium (outer membrane = connective tissue & fat) o myocardium (thick muscle layer) o endocardium (inner membrane = enothelial cells)
______ encloses the entire heart.
Pericardium
What is the epicardium?
the outer membrane of the heart wall consisting of CT and fat
What is the myocardium?
the thick muscular middle layer of the heart wall
What is the thick muscular middle layer of the heart wall called?
the myocardium
What is the outer membrane of the heart wall consisting of CT and fat called?
the epicardium
What is the endocardium?
the inner membrane of the heart wall containing endothelial cells
What is the inner membrane of the heart wall containing endothelial cells called?
the endocardium
Describe the pericardium.
a fluid-filled sac that encloses the entire heart but is not connected to it. Stiff and non-compliant- resists sudden distention of heart chambers
What is pericarditis?
inflammation of the pericardium, which restricts filling of the heart
Which ventricle is bigger and has thicker walls?
the left ventricle
Where is the tricuspid valve?
between right atrium & right ventricle
Where is the pulmonic valve?
between right ventricle & pulmonary artery
Where is the mitral valve?
between left atrium & left ventricle
Where is the aortic valve?
between left ventricle & aorta
Which valve is between the left ventricle & aorta?
the aortic valve
Which valve is between the left ventricle & left atrium?
mitral valve
Which valve is between the right ventricle & pulmonary artery?
the pulmonic valve
Which valve is between the right atrium and right ventricle?
the tricuspid valve
Name the 2 atrioventricular valves.
- tricuspid 2. mitral
What attaches to the atrioventricular valves?
chordae tendonae
Name the 2 semilunar valves.
- pulmonic 2. aortic
What are chordae tendonae?
tendon-like attachments that prevent valves from prolapsing into atria during ventricular contraction
What are valves made of?
thin flaps of fibrous tissue covered by endothelium
What is a valve prolapse?
major valve failure where the valve gets pushed backwards
Where is the SA node located?
in the wall of the R atrium
How does the SA node depolarize? What does this do?
spontaneously; initiates the heart beat
What is the intrinsic bpm for the SA node alone?
100 bpm
What regulates the SA node?
the ANS and many humoral factors
How does the SA node impulse spread through the atria?
via gap junctions
What is the purpose of the AV node between the atria and ventricles?
slows conduction to allow atrial contraction to precede ventricular contraction
What is the His-Purkinje system?
specialized cells that rapidly conduct depolarization to trigger coordinated ventricular contraction
What are specialized cells that rapidly conduct depolarization to trigger coordinated ventricular contraction called?
the His-Purkinje system
When does the majority of coronary blood flow occur and why?
during diastole bc of compression of microvasculature during systole
Coronary blood flow depends on _____.
heart rate
Describe the L main coronary artery.
it’s short (~1cm), bifurcates into L anterior descending artery (LAD) and circumflex artery, and is the 1a blood supply to the L atrium and L ventricle
Describe the R main coronary artery.
it sits in the groove btw the R atrium and R ventricle and is the 1a blood supply to the R atrium and R ventricle, as well as parts of the post. L ventricle
Where do the coronary veins drain?
into the coronary sinus
Where does the coronary sinus drain?
into the R atrium near the IVC
What are the wall differences btw the aorta and the vena cava?
aorta: thicker wall, more elastic fibers vena cava: larger internal radius, more smooth muscle and lots more collagen fibers
Why do arterioles have thicker walls than the arteries?
they have more vascular smooth muscle
Where is the major site of regulation of vascular resistance?
in the arterioles
Describe a capillary.
smallest vessels- single layer of epithelial cells- no smooth muscle- 1a site of gas and nutrient exchange
Where is most of the blood volume at any given time?
in the veins/venules
What are the 3 layers of a blood vessel wall?
- tunica adventitia 2. tunica media 3. tunica intima
What is the tunica adventitia?
the outermost BV layer consisting mainly of CT (collagen and elastin)
What is the tunica media?
the middle BV layer consisting mostly of innervated vascular smooth muscle
What is the tunica intima?
the inner layer of the BV lined with vascular endothelium
Where does athrosclerotic plaque formation occur?
in the tunica intima
What are precapillary sphincters?
smooth muscle bands at junction of arterioles and capillaries
How is blood flow thru capillary beds regulated?
constriction/dilation of arterioles and precapillary sphincters
Movement of substances between capillaries and tissue is driven by _____ and ______.
concentration; pressure gradients
What is lymph?
excess interstitial fluid
How are lymphatic capillaries different?
they’re blind end- less numerous- much more porous w/o tight junctions
Lymph flows into lymphatic capillaries in response to _______, _______, and _______.
increased interstitial pressure; contraction of smooth muscle in lymph vessels; contraction of surrounding skeletal muscle
How are lymph vessels similar to veins?
they have valves
Where does lymph rejoin circulation?
in the subclavian veins
What is the amount of lymph flow per day?
2-4 L/day
When does edema occur?
when intersitial fluid exceeds the capacity of the lymphatic system
What is the amount of blood flow per day?
7000L/day
