Chapter 23: Vessels and Circulation

________________ extends to all body regions while _____________________________ consists of vessels to and from lungs

system circulation, pulmonary circulation

arteries carry blood __________ from the heart

away

arteries become progressively smaller as they branch and lead to?

capillaries

veins _______ blood to the heart

return

veins become progressively ______ as they merge and approach heart

larger

capillaries are the ___________ vessels

exchange

What is a convergence of two or more vessels?

anastomosis

what are adjacent arteries and veins?

companion vessels

how many layers do walls of arteries and veins have?

3

What are the layers of walls of arteries and veins called?

tunics

what are the three layers (tunics) of walls of arteries?

• tunica intima

• tunic media

• tunica externa

what is the tunica intima composed of?

endothelium (simple squamous lining) and subendothelial layer of areolar CT

what is tunic media composed of?

smooth muscle

sympathetic activity in tunic media causes?

vasoconstriction

what tunic is composed of outer CT that helps anchor blood vessel to surroundings?

tunica externa

large thick blood vessels require?

vasa vasorum

What is own network of blood small vessels on their outer layer?

vasa vasorum

walls of capillaries only contain which layer (tunic)?

tunica intima

do arteries and veins have valves?

only veins

what is the thickest wall in arteries?

tunica media

What is the thickest wall in veins?

tunica externa

What are the three types of arteries?

• elastic arteries

• muscular arteries

• arterioles

Which are the largest arteries?

elastic arteries

which type of arteries walls contain many elastic fibers, especially abundant in tunica media?

elastic arteries

where are most examples of elastic arteries found?

near the heart

what are examples of elastic arteries?

aorta, pulmonary, and brachiocephalic arteries

what allows stretch in elastic arteries when heart pumps blood to them?

elastic fibers

elastic arteries branch into?

muscular arteries

muscular arteries are __________-sized arteries

medium

What type of artery have proportionally thicker tunica media with multiple layers of smooth muscle cells?

muscular arteries

muscular arteries possess elastic fibers in two concentric rings which are?

• internal elastic lamina

• external elastic lamina

which concentric ring separates tunica intima and tunica media?

internal elastic lamina

which concentric ring separates tunica media and tunica externa?

external elastic lamina

muscular arteries branch into?

arterioles

what is an example of a muscular artery?

brachial artery

what are the smallest arteries?

arterioles

generally, all arterioles have less than six cell layers of ________________ in tunica media

smooth muscle

sympathetic innervation to muscle fibers of tunica media causes?

vasocontriction

vasocontriction elevates ___________ and decreases ___________ to downstream capillaries

blood pressure, local blood flow

What are the smallest blood vessels?

capillaries

what type of blood vessel solely consists of tunica intima (single layer of endothelial cells and basement membrane)?

capillaries

what do capillaries allow for?

metabolic exchange between blood and tissues

capillaries are considered what of the cardiovascular system?

functional units 

groups of capillaries form?

capillary beds 

each capillary bed is fed by?

metarteriole

the origin of each true capillary has?

precapillary sphincter

What is cyclical periods of contracting and relaxing?

vasomotion

What are the types of capillaries?

• continuous

• fenestrated

• sinusoids

what type of capillary do endothelial cells form a complete lining aided by tight junctions?

continuous

what is the most common type of capillary?

continuous

Where are examples of continuous capillaries?

muscle and brain

What type of capillary has endothelial cells that contain fenestrations that allow fluid exchange between blood and intersitital fluid?

fenestrated 

Where are examples of fenestrated capillaries?

small intestine and kidney

What type of capillaries have large gaps between endothelial cells and a discontinuous (or absent) basement membrane?

sinusoids

what type of capillaries allow for transport of large molecules and cells to and from blood?

Sinusoid

where are examples of sinusoid capillaries?

bone marrow and liver

what drains capillaries and retuns blood to the heart?

veins

pressure in _______ is much lower than in arteries

veins

veins function as?

blood reservoirs

what are the smallest veins?

venules

venules are companion vessels with?

arterioles

what are the smallest venules?

postcapillary venules

What is leukocytes migrating from bloodstream to interstitial fluid?

diapedesis 

diapedesis occurs through walls of ?

postcapillary venules

venules merge to form?

veins

smaller and medium-sized veins travel with?

muscular arteries

large veins travel with?

elastic arteries

blood pressure in veins is _________, so most contain _________ to prevent from pooling

low, valves

valves are formed from?

tunica intima

muscles bulging as they contract and push on veins to help move blood toward the heart is?

skeletal muscle pump

venous return is also assisted by?

respiratory pump

what involves changes in intrathoracic and intra-abdominal pressure?

respiratory pump

What is the force per unit are that blood places on the inside of a blood vessel?

blood pressure

what is blood pressure measured with?

sphygmomanometer 

What is pressure during ventricular contraction?

systolic blood pressure

What is pressure during ventricular relaxation?

diastolic blood pressure

pressure is ________ until it reaches capillaries

pulsatile

pressure decreases from?

aorta to vena cava

what is considered normal BP?

120/80 or 110/70 (systolic/diastolic)