A10-Blood Pressure and Heartbeat Flashcards
A complete heartbeat is called a…
cardiac cycle
-This involves a full contraction and relaxation of each chamber of the heart
The cardiac cycle is usually divided into two basic phases
diastole and systole phase
disastole phase
when the heart is relaxed and filling with blood
systole phase
when the heart contracts and is emptying
The cardiac cycle: Diastole begins when…
Relaxed atria fill with blood
-As it fills, pressure pushes the atrioventricular valves open abd blood begins to fill relaxed ventricle
-Atria folls and musculars wall of atria contact and ventricles completely fill with blood they contract
The cqardiac cycle: This ________ of ventricles marks the start of systole phase
Contraction
- Increasing pressure forces the atrioventriclular valves shut, pushing blood through the semilunar valves and into arteries
- Valves relac and volume in ventricles increases
-Pressure in ventricles decreases
-Blood is prevented from re-entering ventricles by closing of semilunar valve
-
“lubb-DUBB” of the heartbeat is actually caused by the…
opening and closing of heart valves
The “lubb” occurs when….
the atrioventricular valves close and the ventricles begin to contract
The “DUBB” occurs when…
ventricles relax and the semilunar valves snap shut
Instrument used to listent to heart
stethoscope
If the heartbeat sounds are not normal this may be a sign of a
leaking valve, known as a heart murmur
What heart muscle has the ability to contract and relax on its own without stimulation of nerves?
myogenic muscle
-This is why someone with a damaged nervous system may still have a beating heart
The contraction that initiates the heartbeat is from a cluster/group of cells in the right atrium called the….
sinoatrial (SA) node
What does the SA nodes do speficially?
cells sends an electrical signal which causes the atria to contract
SA Node acts as a…
pacemaker
- its signals are responsible for setting a normal rhythm of the heartbeat