objective 4 pt 1

Question 1

the delivery system that begins and ends at heart
works with lymphatic system to circulate fluids

Answer 1

blood vessels

Question 2

carry blood away from heart; carry oxygenated blood except for pulmonary artery and umbilical vessels of fetus

Answer 2

arteries

Question 3

site of gas exchange; directly serve cellular needs; connect arteries and veins

Answer 3

capillaries

Question 4

carry blood toward heart; carry deoxygenated except for pulmonary veins and umbilical vessels of fetus

Answer 4

veins

Question 5

central blood-containing space, surrounded by a wall

Answer 5

lumen

Question 6

what are the 3 layers of tunics of a vessel?

Answer 6

tunica intima
tunica media
tunica externa

Question 7

Innermost layer that is in “intimate” contact with blood
– Contains endothelium which is found in lumen of all
vessels
– Endothelium is continuous with endocardium
– Its slick surface reduces friction

Answer 7

tunica intima

Question 8

Middle layer
– mostly smooth muscle and sheets of elastin
– Innervated by Sympathetic nervous system, controlling:
– Bulkiest layer responsible for maintaining blood flow
and blood pressure

Answer 8

tunica media

Question 9

Outermost layer
– Also called
tunica adventitia
– Composed mostly of loose collagen fibers that protect
and reinforce vessel wall and anchor it to surrounding
structures
– Infiltrated with nerve fibers & lymphatic vessels
– Large veins also contain elastic fibers in this layer

Answer 9

tunica externa

Question 10

decreased lumen diameter

Answer 10

vasoconstriction

Question 11

increased lumen diameter

Answer 11

vasodilation

Question 12

system of tiny blood vessels found in
larger vessels
– Function to nourish outermost external layer

Answer 12

vasa vasorum

Question 13

what are the 3 groups of arteries?

Answer 13

elastic arteries
muscular arteries
arterioles

Question 14

large arteries close to heart
◦ Aorta and its major branches
◦ conducting arteries because they conduct blood from
heart to medium sized vessels
} Contains elastin
} Contains smooth muscle, but inactive in
vasoconstriction
} Act as pressure reservoirs that expand and recoil
as blood is ejected from heart
◦ Allows for continuous blood flow downstream even
between heartbeats

Answer 14

elastic arteries

Question 15

Elastic arteries give rise to muscular arteries
}
distributing arteries because they deliver blood to
body organs
} Account for most of named arteries
} Have thickest tunica media with more smooth
muscle
} less elastic tissue
◦ Tunica media sandwiched between
elastic
membranes
} Active in vasoconstriction

Answer 15

muscular arteries

Question 16

smallest of all arteries
◦ Various sizes
◦ Regulate flow into capillary beds via vasodilation
and vasoconstriction of smooth muscle
◦ resistance arteries because changing diameters of
lumens changes resistance to blood flow
◦ Lead to capillary beds

Answer 16

arterioles

Question 17

Smallest of 3 types of blood vessels
} Microscopic; diameters so small only single
RBC can pass through at a time
} Strategically placed pericytes
} Walls have only a thin tunica intima
} Supply almost every cell, except for cartilage,
epithelia, cornea, and lens of eye

Answer 17

capillaries

Question 18

what is the function of capillaries?

Answer 18

exchange of gases, nutrients,
wastes, hormones, etc., between blood and
interstitial fluid

Question 19

what are the 3 types of capillaries?

Answer 19

continuous capillaries
fenestrated capillary
sinusoidal capillaries

Question 20

Abundant in skin, muscles, lungs, and CNS
– Continuous capillaries of brain are unique
– Form blood brain barrier
– Least permeable as they lack pores
– Often have pericytes

Answer 20

continuous capillaries

Question 21

Found in areas involved in active filtration (kidneys),
absorption (intestines), or endocrine hormone
secretion
– Endothelial cells contain Swiss cheese–like pores called
(
fenestrations) to promote permeability
– Moderate permeability

Answer 21

fenestrated capillary

Question 22

Most permeable of the capillaries
– Fenestrated with larger clefts; incomplete basement
membrane
– Found only in the liver, bone marrow, spleen, and
adrenal medulla
– Blood flow is sluggish—allows time for modification of large
molecules and blood cells that pass between blood and tissue
– Contain macrophages in lining to capture and destroy
foreign invaders

Answer 22

sinusoidal capillaries

Question 23

interwoven network of capillaries between arterioles and venules

Answer 23

capillary bed

Question 24

smallest form of artery

Answer 24

arteriole

Question 25

smallest form of vein

Answer 25

venule

Question 26

flow of blood through capillary bed

Answer 26

microcirculation

Question 27

carry blood from capillary bed toward the heart } Contains valves } Formation begins when capillary beds unite in venules and merge into larger and larger ______

Answer 27

veins

Question 28

Smallest form of a vein – Very porous; allow fluids and WBCs into tissues – Large venules have one or two layers of smooth muscle cells

Answer 28

venules

Question 29

Have all 3 tunics, but thinner walls with large lumens compared to arteries } Tunica media is thin, contains little smooth muscle or elastin } Tunica externa is thick, contains collagen fibers and elastic networks } Large lumen and thin walls make veins good storage vessels (contain upto 65% of blood supply)

Answer 29

veins

Question 30

prevent backflow of blood most abundent in veins of limbs

Answer 30

venous valves

Question 31

Flattened veins with extremely thin walls – Composed only of endothelium

Answer 31

venous sinuses

Question 32

diameter lumens offer little resistance so this ensures blood returns to heart at same rate it was pumped into circulation

Answer 32

large

Question 33

interconnections between blood vessels the provide alternate channels for blood flow

Answer 33

vascular anastomoses

Question 34

provide alternate pathways even if one artery is blocked ◦ Common in joints, abdominal organs, brain, and heart; none in retina, kidneys, spleen

Answer 34

arterial anatomoses

Question 35

shunts in capillaries

Answer 35

arteriovenous anastomoses

Question 36

so abundant that occluded veins rarely block blood flow

Answer 36

venous anastomoses

Question 37

volume of blood flowing through vessel, organ, or entire circulation in given period ◦ Measured in ml/min, it is equivalent to cardiac output (CO) ◦ relatively constant when at rest, but at any given moment, varies at individual organ level, based on needs

Answer 37

blood flow

Question 38

force per unit area exerted on wall of blood vessel by blood ◦ Expressed in mm Hg ◦ Pressure gradient provides driving force that keeps blood moving from higher- to lower-pressure areas

Answer 38

blood pressure

Question 39

opposition to flow ◦ Measurement of amount of friction blood encounters within vessel walls, generally in systemic circulation

Answer 39

resistance (peripheral resistance)

Question 40

what are the 3 most important sources of resistance?

Answer 40

Blood viscosity – Blood vessel length – Blood vessel diameter

Question 41

The thickness or “stickiness” of blood due to formed elements and plasma proteins – The greater the viscosity, the less easily molecules are able to slide past each other – Increased viscosity equals increased resistance

Answer 41

blood viscosity

Question 42

The longer the vessel, the greater the resistance encountered

Answer 42

total blood vessel legnth

Question 43

Has greatest influence on resistance – Frequent changes alter resistance – Viscosity and blood vessel length are generally constant – Resistance varies inversely with vessel diameter – If diameter of a vessel increases, resistance decreases, and vice-versa

Answer 43

blood vessel diameter

Question 44

diameter arterioles are major determinants of resistance as diameter changes frequently, in contrast to larger arteries that do not change often

Answer 44

small

Question 45

Pumping action of heart generates blood flow } Pressure results when flow is opposed by resistance } Systemic pressure is highest in aorta and declines throughout pathway ◦ Steepest drop occurs in arterioles, where resistance is greatest

Answer 45

systemic blood pressure

Question 46

what is arterial blood pressure determined by?

Answer 46

Elasticity ( compliance or distensibility) of arteries close to heart 2. Volume of blood forced into them at any time

Question 47

rises and falls with each heartbeat

Answer 47

pulsatile

Question 48

pressure exerted in aorta during ventricular contraction ◦ Left ventricle pumps blood into aorta, that stretches aorta ◦ Averages 120 mm Hg in normal adult

Answer 48

systolic pressure

Question 49

when heart is at rest

Answer 49

diastolic pressure

Question 50

difference between systolic and diastolic pressure (systolic – diastolic)

Answer 50

pulse pressure

Question 51

throbbing of arteries due to difference in pulse pressures, which can be felt under skin

Answer 51

pulse

Question 52

pressure that keeps blood moving throughout the cardiac cycle

Answer 52

mean arterial pressure

Question 53

pulse and blood pressure, along with respiratory rate and body temperature

Answer 53

vital signs

Question 54

most common

Answer 54

radial pulse

Question 55

areas where arteries are close to body surface

Answer 55

pulse points

Question 56

less than 120mmHg Pressure when sounds first occur as blood starts to spurt through artery

Answer 56

systolic pressure

Question 57

less than 80 mmHg Pressure when sounds disappear because artery is no longer constricted, blood is flowing freely

Answer 57

diastolic pressure

Question 58

Changes little during cardiac cycle } Important for return flow to heart and CO } Small pressure gradient, only about 15 mm Hg ◦ If vein is cut, low pressure of venous system causes blood to flow out smoothly ◦ If artery cut, blood spurts out because pressure is higher } Low pressure is due to resistance } Non-pulsatile } Low pressure of venous side requires adaptations to help with venous return

Answer 58

venous blood pressure

Question 59

what are the factors that aid venous return?

Answer 59

muscular respiratory sympathetic venoconstriction

Question 60

contraction of skeletal muscles “milks” blood back toward heart; valves prevent backflow

Answer 60

muscular

Question 61

pressure changes during breathing move blood toward heart by squeezing abdominal veins as thoracic veins expand

Answer 61

respiratoru

Question 62

under sympathetic control, smooth muscles constrict, pushing blood back toward heart

Answer 62

sympathetic venoconstrictionn

Question 63

what are the 3 main factors regulating BP?

Answer 63

cardiac output peripheral resistance blood volume

Question 64

what can factors of BP be affected by?

Answer 64

neural controls hormonal controls renal controls