Ch 20-The circulatory system- Blood Vessels Circulation

Question 1

Arteries relationship to heart

Answer 1

carry blood away from heart

Question 2

veins relationship to heart

Answer 2

carry blood back to heart

Question 3

capillaries

Answer 3

connect smallest arteries to smallest veins to create a circuit

Question 4

wall artery layers (around RBC)

Answer 4

tunica interna-lines the blood vessel and exposed to blood

tunica media- middle layer, smooth muscle, contraction of muscle controls diameter

tunica externa- outermost layer, loose connective tissue

Question 5

arteries vs veins

Answer 5

Arteries
-higher pressure
-no valves
-tunica media more prominent
-pulse blood flow

veins
-lower pressure
-most have valves
-tunica media less prominent
-steady blood flow

Question 6

arteries

Answer 6

-large- also known as conducting and they expand during systole and recoil during diastole (eg arota)

-med- also known as distributing and it distributes blood to organs (eg brachial)

-small- also known as resistance and it controls the amount of blood to organs ( eg Arterioles which have the biggest impact on blood pressure)

Question 7

metaarterioles

Answer 7

vessels that link Arterioles to venules allowing shortcuts for blood to bypass

Question 8

aneurysm, dissecting aneurysm and the sites/reason

Answer 8

-weak point in artery or heart wall
-bulging sac that pulsates and may rupture

Dissecting aneurysm: blood buildup
between artery and separates them

most common sites: abdominal aorta, base of brain

-most common cause is high blood pressure

Question 9

baro and chemoreceptors

Answer 9

carotid sinuses: baroreceptors
carotid bodies: chemoreceptors
aortic bodies: chemoreceptors

Question 10

capillaries and its three types

Answer 10

-exchange vessels

-gases nutrients waste and hormones pass through

-three types:

continuous - least permeable, occurs in most parts of body, tight junctions, pericytes wrap around capillaries, passes solutes and glucose

fenestrated- organs that require rapid absorption or filtration, have pores called fenestrations, passage of small molecules

sinusoids-found in liver, bone marrow, large fenestrations for bigger passage of molecules

Question 11

Capillary perfusion

Answer 11

-75% of body’s capillaries are shut down
-Precapillary sphincters control flow in capillary beds

-When sphincters are relaxed, capillaries are well perfused with
blood
-When sphincters contract, they constrict the entry to the
capillary and blood bypasses the capillary

Question 12

veins and types

Answer 12

-capacitance vessels
-thin walled with steady blood flow
-collapse when empty, expand easily

types:
-postcapillary: smallest veins

-varicose- Standing for long periods promotes blood pooling in the
lower limbs and stretches the veins, twisted looking,

Question 13

Variations in Circulatory Pathways

Answer 13

simplest way: 1 capillary bed, most common way to tranfer blood

portal way- 2 capillary beds, blood flows through two netwrokds before returning to heart

anastomosis- two vessels other than capillaires, shunt, flows directly into vein bypassing capillaries, two types: venous (most comm) and arterial

Question 14

pulse pressure

Answer 14

difference between systole and diastole pressure

Question 15

MAP (mean arterial pressure)

Answer 15

diastolic pressure + 1/3 of pulse pressure

Question 16

hypertension vs hypotension

Answer 16

hyper: High blood pressure

hypo: Chronic low resting BP

Question 17

blood pressure determination variables

Answer 17

• Cardiac output
• Blood volume
• Resistance to flow

Question 18

Peripheral resistance and its three variables

Answer 18

opposition to flow that blood encounters in vessels away from the heart

variables:
-* Blood viscosity - (thickness of blood)
-Vessel length
-vessel radium (greatest impact)

Question 19

vessel radius and laminar flow

Answer 19

VR- affects blood velocity, only way of controlling resistance

LM- flows in layers, faster in center

Question 20

Blood flow (F) proportional to fourth power of radius (r) equation

Answer 20

𝐹 α 𝑟4

Question 21

Arterioles are

Answer 21

most significant point of
control over peripheral resistance and flow

Question 22

vasomotion and ways to control it

Answer 22

quick and powerful way of altering blood pressure and flow

Three ways of controlling vasomotor activity:
-neural
-local
-hormonal

Question 23

hormonal control and which raises and which lowers

Answer 23

-Hormones influence blood pressure
-raise: epi and nor epi, Angiotensin II

-Lowers:Natriuretic peptides

Question 24

Two purposes of vasodilation and vasoconstriction

Answer 24

-General control of BP

• Routing blood from one body region to another

Question 25

Chemicals pass through capillary wall by three routes:

Answer 25

* Endothelial cell cytoplasm * Intercellular clefts between endothelial cells * Filtration pores (fenestrations) of fenestrated capillaries

Question 26

edema

Answer 26

-excess fluid in a tissue -big ankles

Question 27

venous return

Answer 27

-The flow of blood back to the heart relies on: -pressure gradient: Blood pressure is most important force in venous return -Gravity: Drains blood from head and neck -Skeletal muscle pump -Contraction -Thoracic pump: inhalation expanding thoracic -Cardiac suction During contraction of the ventricles, valves are pulled downward and atrial space expands

Question 28

what is shock? Name some types

Answer 28

-Inadequate pumping of heart types: -Hypovolemic shock: (most comm) Loss of blood volume from trauma, burns, dehydration -Venous pooling shock - Long periods of standing, sitting, or widespread vasodilation -Septic shock * Bacterial toxins trigger vasodilation

Question 29

does the brain regulate its own blood flow?

Answer 29

yes

Question 30

Transient ischemic attacks (TIAs)

Answer 30

-Brief episodes of cerebral ischemia Caused by spasms of diseased cerebral arteries, can be early warning of a stroke

Question 31

Stroke, or cerebral vascular accident (CVA)

Answer 31

Sudden death of brain tissue caused by ischemia

Question 32

ischemia

Answer 32

lack of blood

Question 33

Special circulatory routes (brain, skeletal muscles, lung)

Answer 33

-brain: brain regulates own blood flow -muscles: arterioles constricts at rest and dialate during exercise -lungs: slower for gas exchange