The Heart & Circulation Flashcards
myocardium is the..
heart ms
what supplies the right atrium?
superior & inf vena cava
LV pumps blood via the ..
aorta
when do the AV valves close? & what is their purpose?
close when ventricular walls contract; prevent backflow of blood during ventricular systole
what is the purpose of semilunar valves?
to prevent backflow of blood from aorta & pulmonary artery during diastole
systole is the period of..
ventricular contraction
diastole is the period of..
ventricular relaxation
when does teh blood circulate throughtout the myocardium? and via what?
during diastole via coronary arteries
what coronary artery supplies the AV node & bundle of His?
RCA
what coronary artery supplies the left ventricle?
LAD
what is the purpose of the coronary sinus?
receives venous blood from the heart and empties it into the R atrium
the SA node initiates an impulse rate of..
60-100 bpm
normal range of stroke volume is..
55-100 mL/beat
3 things that influence SV:
- preload (diastolic filling, aka left ventricle end diastolic volume)
- contractility
- afterload - the force the LV must generate to overcome the aortic pressure
CO =
SV * HR
ejection fracture is..
the % of blood emptied from the ventricle during systole
**a CLINICALLY USEFUL MEASURE OF LV FXN*
EF = SV/LVEDV
What is a “normal” EF?
> 55%; LOWER means GREATER DYSFXN
atrial filling pressure is..
the difference b/t venous & ATRIAL pressures
-so, when you have a STRONG VENTRICULAR CONTRACTION, the ATRIAL FILLING IS ENHANCED
(high–>low pressure)
IF you have an increased HR OR heart disease, what is the effect on diastolic filling time?
decreases (so LOWER end diastolic volume - normally 120 mL)
the Myocardial oxygen deman is cliniclaly measures by..
HR * SBP (rate pressure produce)
Arteries transport..
Oxygenated blood from areas of high to low pressure
Capillaries function for ..
Exchange of nutrients and fluids between blood and tissues
Venous circulation is influenced by (4)
Ms contraction, gravity, respiration (insp causes incr return) and compliance of R heart
What organs are lymphatic?
Tonsils, spleen, lymph nodes, thymus, & thoracic duct
Once lymph has been drained From the lymphatic system it goes,.
To the venous system
Lymphatic capillaries –> lymph vessels –> ducts–> left subclavian vein
How does the lymphatic system contribute to immune system function?
Lymph nodes collect cellular debris and bacteria, remove excess fluid, blood waste and protein molecules; and produce antibodies
Control of PS & sympathetic stimulation is located in..
The medulla oblongata
PS stim transmitted via ..
Vagus nerve - releases ACh
Sympathetic stimulation transmitted via ..
t1-4 cord segments, upper thoracic to superior cervical chain ganglia; innervates all but the ventricular myocardium (but PS innervates that)
-releases epinephrine and norepinephrine
Drugs that incr sympathetic functioning are called .
Sympathomimetics
The main mechanisms controlling the heart are..
Baroreceptors
-located in aortic arch and carotid sinus
The circulatory reflex in response to increased BP is..
PS stimulation , decr rate and force of cardiac contraction, inhib of symp system –> decreased peripheral resistance
Chemoreceptors are located —
- role?
In carotid body
- IF increased CO2, decr O2 OR decr pH(incr lactic acid), an INCREASED HR occurs
What two ion concentration imbalances can cause a decreased heart rate ?
HYPERkalemia & HYPOcalcemia
What is an adverse effect of HYPOkalemia?
Arrhythmias which could progress to ventricular fibrillation
What is an adverse result of hypermagnesium?
Arrhythmia OR cardiac arrest (because incr magnesium is a calcium blocker)
What is an adverse response to hypo magnesium?
Ventricular Arrhythmias, coronary artery vasospasm and sudden death
