Chapter 12 Pt. 1 (Final Exam Pt. 3) Flashcards
cardiovascular system, consists of the ______ and the _______ _______
heart
blood vessels
A muscular pump that contracts rhythmically and provides the force that moves the blood, is called?
heart
What are blood vessels?
a system of tubules through which blood flows
What is the blood cycle?
heart —> artery—> arterioles—> capillary—> venule—> vein
What is the difference between veins and arteries?
Veins-carry blood back to the heart
Arteries- carry blood away from heart
the hollow interior of a blood vessel, through which the blood flows, is called the ______
lumen
___________, a lining that provides a smooth surface that minimizes friction so that the blood flows easily
endothelium
the _______ and ___________ are characteristics of all blood vessels
lumen
endothelium
What is the inner layer of a vein made of?
What is the middle layer of a vein made of?
What is the outer layer of a vein made of?
inner layer=endothelium
middle layer= smooth muscles & elastic fibers
outer layer=connective tissue
What makes up a venule?
valve
connective tissue
endothelium
What is the inner layer of an artery made of?
What is the middle layer of an artery made of?
What is the outer layer of an artery made of?
inner layer=endothelium
middle layer=smooth muscle and elastic fibers
outer layer=connective tissue
Arterioles are made out of?
smooth muscle and endothelium
Capillaries are made out of?
endothelium and lumen
The elastic fibers in the middle layer of an artery have what 2 important functions?
(1) they help the artery tolerate the pressure shock caused by blood surging into it when the heart contracts
(2) they help maintain a relatively even pressure within the artery, despite large changes in the volume of blood passing through it
What is an aorta?
the body’s main artery
a pressure wave created by the alternate expansion and recoil of arteries, is called?
pulse
What is a vasoconstriction?
a result of circular muscle contracting and the diameter of the lumen becomes narrower
Does vasoconstriction increase or decrease blood flow?
decrease
What is vasodilation?
a result of smooth muscle relaxing and the arterial lumen increasing in diameter
Does vasodilation increase or decrease blood flow?
increase
What is an aneurysm?
when the arterial wall becomes weakened, the pressure of the blood flowing through the weakened area may cause the wall to swell outward like a balloon
What are the risk factors of an aneurysm?
- it bursts, causing blood loss
- forms blood clots
What are arterioles?
the smallest arteries
What are the 2 important regulatory roles of arterioles?
(1) they are the prime controllers of blood pressure
(2) serve as gatekeepers to the capillary networks
What are capillaries?
are microscopic blood vessels that connect arterioles and venules
True or False: capillaries combined cross-sectional area is enormous, much larger than arteries or veins
True
What is the primary function of capillaries?
to exchange materials between the blood and the body cells
What happens at the arterial end of a capillary?
blood pressure forces fluid out of the capillary to the fluid surrounding tissue cells
What happens at the venous end of a capillary?
fluid is drawn back into the capillary by osmotic pressure
True or False: capillaries are so wide that red blood cells can travel in groups
False; they are so NARROW that red blood cells must travel through them in single file
What is a capillary bed?
a network of capillaries
What is a pre capillary sphincter?
a ring of smooth muscle that surrounds the capillary where it branches off the arteriole and regulates blood flow into it
What is a venule?
the smallest kind of vein
True or False: the walls of the veins are thick
False; the walls of veins are thin
What are the 3 mechanism move blood from lower parts of the body toward the heart?
(1) valves in veins prevent back flow of blood
(2) contraction of skeletal muscles squeezes veins
(3) breathing causes pressure changes that move blood toward the heart
