“BASIC SUMMARY” of CARDIOVASCULAR PHYSIOLOGY. The purpose/goal of C.V.S. is : adequate PERFUSION of the Tissues PERFUSION = BLOOD FLOW, THUS, DELIVERY of vital O 2 nutrients, etc, REMOVAL of wastes.
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of C.V.S. is : adequate PERFUSION of the Tissues
PERFUSION = BLOOD FLOW,
DELIVERY of vital O2 nutrients, etc,
REMOVAL of wastes.
“HEMODYNAMICS” refers to ALL the mechanisms
(blood moving/changing) involved in keeping blood flow ‘normal’
Proper Electrical and Mechanical Function
of the HEART as a PUMP
3) BLOOD PRESSURE : “ FLOW” of a fluid is dependent upon PRESSURE - and is always
from “high” pressure area to lower pressure area.
Generation and Propagation of a coordinated Impulse to contract, from atrium to ventricle
Conduction system: SA node, AV node, AV Bundle, R and L Bundle Branches, Purkinje system
(graphic measure of conduction: electrocardiogram)
ECG = “EKG” p wave, QRS complex, t wave
B) MECHANICAL FUNCTION
1. CONTRACTILITY of the Myocardium
( strength / force of the contractions)
2. VALVULAR function
SA node AV node
Bundle of His
Right Bundle Branch
Left Bundle Branch
AV Bundle, (Bundle of His)
REGULATED RATE AND RHYTHM:
Rate -- optimal rate depends on demand.
normal at rest 60-100 bpm
(Lance Armstrong’s is in the 30’s )
abnormal rates: bradycardia too slow
tachycardia too fast
RHYTHM -- SHOULD BE REGULAR
not skippy or chaotic
Onset, supraventricular tachycardia, rate ~120
Normal sinus, rate ~64 bpm
Atrial fibrillation, V.rate
a terminal rhythm
CONTRACTILITY of the MYOCARDIUM:
the strength / force & completeness
of the Contractions
(effects of ischemia / necrosis; CAD, HTN drugs, etc)
The essence of “Congestive Heart Failure”
is usually that of INADEQUATE
squeeze capacity of the heart muscle
DIASTOLE - atria contract,
Vent. relax; blood flows thru the AV valves, fills Ventricles.
(P wave on the EKG)
SYSTOLE –Ventricles contract,
Blood EJECTED into Aorta
and Pulm. Trunk, Art.
(QRS complex on the EKG)
INSUFFICIENCY: abnormal “Backflow “
the “ Heart Sounds “ are made by the valves closing –
‘ Lub Dupp lub dupp lub dupp
Murmur : swishing sound , made by TURBULENCE
of flow can be either from Stenosis
*** abnormal valvular function affects Cardiac Output directly, and indirectly by eventually affecting Contractility of the muscle
CARDIAC HEART RATE X STROKE VOLUME
OUTPUT pulse amt blood ejected
beats per minute each beat
“Hydration” status (intake -- outgo) diuresis, diarrhea, vomiting, sweating, hyperthermia/ fever,
Proper blood production by bone marrow
Lack of ‘hemorrhage’, or blood loss
complex regulatory mechanisms involving kidney function, endocrine regulatory centers, plasma protein conc., & others
Account for the Alterations /adjustments in
(increased flow to MUSCLES during exercise,
Whereas Blood Flow to BRAIN and KIDNEYS must remain rel. CONSTANT
SPHYGMOMANOMETER AND STETHOSCOPE
SYSTOLIC BLOOD PRESSURE /
DIASTOLIC BLOOD PRESSURE
There are 2 FUNCTIONAL VENOUS
1. SKELETAL MUSCLE CONTRACTIONS, and
2. RESPIRATORY MOTIONS create negative inspiratory pressure, which ‘’SUCKS’ VENOUS BLOOD INTO THE THORAX, TOWARD THE HEART
must mention : CAPILLARIES –
Where the ‘ACTION IS’ regarding EXCHANGE of
substances between the Vascular &
INTERSTITIAL spaces , at the
Cells / Tissues level. (fluid, o2, co2 WBC’s,
molecules, etc ) can diffuse back and forth
( importance of hydrostatic and osmotic pressure )
Structure of Capillaries: ONLY 1 layer of endothelium and A basement membrane, with “SPACES” for DIFFUSION - no muscle or connective tissue covering. A large number of capillaries in a specific region is called a CAPILLARY BED
Inadequate blood flow to meet cellular needs.
Hypovolemic shock – due to decreased blood volume.
Septic shock (or vascular shock) – due to inappropriate vasodilation, brought about by response to overwhelming infection.
Cardiogenic shock – due to poor heart function.