Circulatory system Flashcards
whole blood consists of:
55% plasma and 45% formed elements: erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.
all of the formed elements are produced from:
stem cells in red bone marrow
Erythrocytes are modified for transport of
oxygen where most of it is bound to the pigmented protein hemoglobin
the 5 types of leukocytes can be distinguished on the basis of:
size, appearance of the nucleus, staining properties, and the presence or absence of visible cytoplasmic granules
white blood cells are active in:
phagocytosis (neutrophils and monocytes) and antibody formation (lymphocytes)
platelets are active in the process of
blood clotting
blood serves to transport __________ and to carry away _________.
oxygen and nutrients; carbon dioxide and metabolic wastes
plasma contains approx. ___________ which are dissolved or suspended in water
10% proteins, ions, nutrients, waste products and hormones
the heart is a double pump that sends blood to the lungs for oxygenation through
the pulmonary circuit and to the remainder of the body through systemic circuit
blood is received by the _______ and is pumped into circulation by the ________
atria; ventricles
valves between the atria and ventricles include
the tricuspid on the right side of the heart and bicuspid on the left
semilunar valves are found at the
entrance of the pulmonary trunk and the aorta
blood supplies to the heart muscle (the myocardium) by
the coronary arteries
blood drains from the myocardium directly into the
right atrium through the coronary sinus
the heart has an intrinsic beat initiated by the
sinoatrial node and transmitted along a conduction system through the myocardium
the cardiac cycle is the period from the end of
one ventricular contraction to the end of the next ventricular contraction
the contraction phase of the cycles is
systole
the relaxation phase is
diastole
the vascular system includes
arteries that carry blood away from the heart, veins that carry blood toward the heart, and the capillaries
the capillaries, the smallest of vessels, are where the exchange of ___________ take place between the blood and surrounding tissues.
water, nutrients, and waste products
the systemic arteries begin with the
aorta which sends branches to all parts of the body
as arteries get farther away from the heart they become
thinner and thinner
what are the smallest arteries called?
arterioles
what are the large veins that empty into the right atrium of the heart?
superior and inferior vena cava
the walls of the arteries are ____ and _____ and they carry blood under ______
thick; elastic; high pressure
vasoconstriction and vasodilation result from
contraction and relaxation fo smooth muscle in the arterial walls; these changes influence blood pressure and blood distribution to the tissues
the walls of the veins are _____ and ____ than those of the arteries and they carry blood under ______.
thinner; less elastic; lower pressure
