Download The heart has four main chambers: the left ______, the left

Heart and circulation worksheet
Please fill in the blanks. In some cases I have given you options e.g.
“sympathetic/parasympathetic” - one of these is the correct answer - and these options
will be found in brackets after the blank space.
The heart has four main chambers: the left and right ________, and the left and right
__________. Blood leaving the _____ side of the heart is oxygenated and is pumped
to the systemic circulation; blood leaving the _____ side of the heart is de-oxygenated
and is pumped to the lungs (through the __________ artery) in order to pick up
oxygen.
The electrical impulse that causes the heart to contract begins in the ____ node, the
natural “pacemaker” of the heart. Excitation spreads across both right and left
_______ until it reaches the ____ node, which introduces a delay. The impulse then
enters the ventricles and causes them to contract.
Blood pressure can be measured by putting a cuff around the upper arm and inflating
it to around 200 mmHg, and listening for blood flowing past the cuff. Pressure is
gradually lowered until the first sounds are heard: this corresponds to _________
(systolic/diastolic) blood pressure and typical values are around _______ mmHg.
Pressure is lowered further, and the sounds become louder and clearer until suddenly
they disappear: the pressure at which the sounds disappear is the __________
(systolic/diastolic) blood pressure and typical values are around _______ mmHg.
The receptors that measure blood pressure are called ___________, and are situated in
the ___________ and the __________. These receptors monitor pressure of blood
leaving the heart and entering the brain respectively. Signals from these receptors pass
into the brainstem centre that controls blood pressure. The output of this centre passes
into the sympathetic and parasympathetic branches of the autonomic nervous system.
A drop in blood pressure increases ___________ (sympathetic/parasympathetic)
nerve activity and this causes the heart rate to ____________ (speed up/slow down)
and resistance of the blood vessels to ___________ (increase/decrease). The
combination of these effects increases blood pressure and thus maintains it at the
correct level.
Since blood pressure is maintained at a stable level, blood supply to different parts of
the circulation can be easily controlled by changing the resistance. The main
resistance vessels are called _________, and are placed between the large arteries and
the capillaries. During exercise, the most striking changes are an enormous increase in
blood supply to the ___________; conversely, the amount of blood flowing to the
___________ system is greatly reduced in exercise.