Unit 2 - Chapter 15 - Circulation of Blood Flashcards
oxygen rich blood is pumped through a series of what
arteries
what is the largest artery in the body
aorta
what do arteries subdivide into
arterioles
what do arterioles do
control the flow into microscopic exchange vessels called capillaries
capillaries are grouped together in something called…..
capillary beds
what do capillary beds do
- supply most of the tissues in the body
- permit the exchange of nutrients and gases between the blood and tissue fluid around the cells
what happens with blood as it exits the capillary beds
it moves into small venules which merge with other venules to form the larger veins
what is the largest vein in the body
superior vena cava and inferior vena cava
give a brief synopsis of the blood vessels and the movement of blood
- arteries carry blood away from the heart and toward capillaries
- veins carry blood toward the heart and away from capillaries
- capillaries carry blood from the tiny arterioles into tiny venules
- aorta carries blood out of the left ventricle of the heart
- vena cavae returns blood to the right atrium after the blood has circulated the body
all vessels are made up of a vessel wall that surrounds a space called a…..
lumen
what are the 3 layers that make up the walls of arteries and veins
- tunica externa (outer layer)
- tunica media (middle layer)
- tunica intima (inner layer)
what is the outer later “tunica externa” composed of
- made of connective tissue fibers
what do the connective tissue fibers of the tunica externa do
- help resist stretching and to prevent it from bursting under pressure
- connect to the extracellular matrix to support the vessel and hold it in place
what is the middle later “tunica media” composed of
- a layer of smooth muscle and a layer of elastic connective tissue
what does the smooth muscle is the tunica media do
- permits changes in blood vessel diameter
- contract or relax to regulate how much blood will flow into a nearby capillary bed
what does the inner layer “tunica intima” consist of
epithelial cells
what is so special about the epithelial cell layer in the tunica intima
it is the only layer
- it’s a single layer of squamous epithelial cells called endothelium
what does the epithelial cell layer in the tunica intima do
- minimizes the accidental formation of blood clots
explain the skeletal muscle pump
- when skeletal muscles surrounding veins contract, the contraction squeezes the walls of the veins which then pushes blood through the venous valves and towards the heart
explain the respiratory pump
- involved pressure changes in the thoracic and abdominal cavities during breathing
when a surgeon cuts into a body, what can they see and what can’t they see
- can see arteries, arterioles, veins, venules
- can’t see capillaries
what are capillaries known as and why
- known as exchange vessels
- because substances such as glucose, oxygen, carbon dioxide, hormones and wastes can quickly pass through the thin endothelial lining
what is the function of arteries and arterioles
- distribute blood from the heart to capillaries
- constricting/dilating
- help maintain adequate arterial blood pressure
what is osmosis
the passive movement of water molecules from an area of lower solute concentration to an area of higher solute concentration throught a membrance that is permeable to water but not to solute
what is filtration
the passive movement of fluid and its dissolved solutes resulting from a hydrostatic pressure gradient where the pressure on one side of the membrane is greater than the pressure on the other side
what is the function of veins and venules
- collect blood from capillaries and return it to the heart
- venules collect blood from the capillaries and then merge with one another to form the veins
- the larger veins serve as blood resevoirs
what is arteriosclerosis (hardening of the arteries)
a common type of vascular disease that blocks arteries and weakens arterial walls
what is arteriosclerosis characterized by
- initial thickening of arterial walls that progresses to hardening as calcium deposits form; this reduces blood flow
- this reduced blood flow leads to ischemia (decreased blood supply to a tissue)
- this eventually leads to necrosis (cell and tissue death)
- necrosis that progresses to decay is called gangerene
what does ischemia mean
decreased blood supply to a tissue
what is necrosis
cell and tissue death
what is gangerene
necrosis that has escalated to cell/tissue decay
what is arteriosclerosis associated with
high blood levels of triglycerides and cholesterol
how can arteriosclerosis be managed
- vasodilators
- angioplasty
what does a vasodilator do
triggers the relaxation of the smooth muscles of the arterial walls, causing the arteris to widen/dilate
what occurs in an angioplasty
- defalted balloon attached to a long tube called a catheter is inserted into a partially blocked artery and then inflated
- as the balloon inflates, the plaque is pushed outward along with the arterial wall; widening the artery to improve blood flow