Arteries, Veins and Peripheral Resistance

Question 1

What are the parts of the circulatory system?

Answer 1

arteries, arterioles, capillaries, venules, veins.

Question 2

What is after load?

Answer 2

it is the force the heart must overcome to push blood into the arteries

Question 3

What is pulse pressure?

Answer 3

the force the heart generates with each contraction to overcome arterial pressure

Question 4

What are the equations of mean arterial pressure (MAP)?

Answer 4

MAP = DBP + 1/3 pulse pressure
MAP = CO x TPR

Question 5

What are the factors that influence pulse pressure?

Answer 5

stroke volume
compliance of arteries
ejection velocity

Question 6

What connective tissue is present is arteries?

Answer 6

elastic

Question 7

What muscle is present in arteries and what layer is it mostly located?

Answer 7

smooth muscle
tunica media

Question 8

What are the major areas of the aorta?

Answer 8

ascending
arch
descending thoracic
descending abdominal

Question 9

What is the size of small arteries?

Answer 9

<2mm

Question 10

What do capillaries form?

Answer 10

large networks

Question 11

How thick are capillaries?

Answer 11

1 cell thick for optimal exchange

Question 12

What do capillary walls lack?

Answer 12

tunica media, tunica adventitia

Question 13

What is the difference between veins and arteries?

Answer 13

veins have larger diameter and lumen
thinner walls
lower pressure
valves to prevent back flow

Question 14

What prevents backwards flow of blood in veins?

Answer 14

valves

Question 15

What type of muscle do blood vessels contain?

Answer 15

smooth

Question 16

How much blood do veins contain at low pressure?

Answer 16

70%

Question 17

What can cause varicose veins (distended -swollen or large)?

Answer 17

weakened vein walls or valves

Question 18

What do weakened vein walls or valves cause?

Answer 18

turbulent blood flow

Question 19

What are the 3 wall layers all vessels share except capillaries?

Answer 19

tunica intima
tunica media
tunica adventitia

Question 20

What do endothelial cells form?

Answer 20

the inner lining of vessels (tunica intima)

Question 21

What do endothelial cells play an important role in?

Answer 21

local BP
provide friction free surface for blood
regulate permeability of vessels
regulation of platelet function and fibrinolysis
promote vessel formation (angiogenesis)

Question 22

What is the structure of the tunica intima?

Answer 22

single line of endothelial cells attached to basement membrane
underlaying layer of extracellular matrix
then internal elastic lamina

Question 23

What is the structure of the tunica media?

Answer 23

layers of elastic fibres and smooth muscle cells (proportion depends on artery type-muscular or elastic)
enables vessel contraction and relaxation

Question 24

What is the structure of the tunica adventitia?

Answer 24

external elastic lamina (separates media)
thick connective tissue (collagen +elastin)
nerve fibres, lymphatics
in larger arteries vasa vasorum

Question 25

What are vasa vasorum?

Answer 25

small arterioles that perfuse the media (vessels of vessels)

Question 26

What is vascular compliance?

Answer 26

ability of a blood vessel to expand and recoil as a response to changes in pressure

Question 27

What is the equation of compliance?

Answer 27

changes in volume / changes in pressure

Question 28

What is an example of arterial compliance?

Answer 28

arterial wall will expand to accommodate ventricular stoke volume

Question 29

What is arteriosclerosis?

Answer 29

a chronic condition in which arteries harden and narrow through build-up of plaques. (plaque contains lipids, fibrous)

Question 30

What can decreased compliance increase?

Answer 30

pulse pressure

Question 31

What is local control of BP?

Answer 31

alteration of small artery and arterioles resistance

Question 32

What are hormones that cause local control of BP?

Answer 32

adrenaline atrial natriuretic peptide (ANP) angiotensin

Question 33

Where is adrenaline released from and where does it bind to most?

Answer 33

adrenal medulla and beta 2 receptors

Question 34

How does ANP cause vasodilation?

Answer 34

increasing sodium ion excretion by the kidneys increasing water loss by urine therefore reduced blood volume

Question 35

Describe the Renin-Anginotensin-Aldosterone-System (RAAS)

Answer 35

1-reduced blood flow to kidney is detected by receptors in juxta-golmerular granular cells causing release of renin 2-renin acts on circulating angioteninogen produced by liver to convert it to anginotensin 1 3- ACE enzyme converts angiotensin 1 to angiotensin 2 which is a potent vasoconstrictor 4 -angiotensin 2 promotes release of aldosterone from the adrenal cortex 5 -aldosterone stimulates Na+ and water reabsorption in distal convoluted tubule which increases blood volume

Question 36

What are examples of ace inhibiting drugs?

Answer 36

captopril enalapril

Question 37

What is an example of a angiotensin 2 receptor blocker?

Answer 37

losartan

Question 38

What vasodilators do endothelial cells release?

Answer 38

Nitric Oxide (NO) Prostaglandin I2 (prostacyclin)

Question 39

What hormone does angiotensin 2 promote release of?

Answer 39

antidiuretic hormone which causes vasoconstriction in V1 SMC

Question 40

What vasoconstrictors do endothelial cells release?

Answer 40

Endothelin 1 (ET-1) Thromboxane A2)

Question 41

What is shear stress?

Answer 41

the force of blood flowing on endothelial layer

Question 42

What can shear stress cause?

Answer 42

release of vasodilators from endothelial cells

Question 43

How does shear stress occur?

Answer 43

blood travelling at different velocities in a blood vessels

Question 44

What can alterations in homeostatic conditions (physiologic or pathologic) cause?

Answer 44

adaptation or disease of blood vessel

Question 45

What are metarterioles?

Answer 45

terminal arterioles that don't have a layer of smooth muscle, but instead smooth muscle fibres surrounding the vessels intermittently

Question 46

What is the branch site of the met arterioles surrounded by?

Answer 46

pre-capillary sphincters that contract and relax in response to metabolic factors

Question 47

What pressure forces fluid from intercellular space to interstitial space?

Answer 47

hydrostatic

Question 48

What pressure forces fluid from interstitial space to intercellular space?

Answer 48

osmotic

Question 49

What is colloid pressure dependant on?

Answer 49

movement of proteins

Question 50

What does negative net filtration mean?

Answer 50

net fluid absorption from interstitial space to capillaries

Question 51

What can build up of fluid in tissues lead up to?

Answer 51

oedema

Question 52

What flows through the lymphatic system?

Answer 52

lymph

Question 53

Can lymph vessels contract?

Answer 53

yes

Question 54

What is the lymphatic system made from?

Answer 54

lymph nodes, and lymph vessels

Question 55

What does the lymphatic system do to excess fluid?

Answer 55

return it to circulation

Question 56

What does the lymphatic system play a central role in controlling?

Answer 56

concentration of proteins in interstitial fluid volume of interstitial fluid interstitial fluid pressure

Question 57

What are pulmonary hydrostatic pressures lower than?

Answer 57

systemic hydrostatic pressure

Question 58

What pressure is equivalent in both systemic and pulmonary?

Answer 58

colloid

Question 59

What can pulmonary oedema be caused by?

Answer 59

heart failure high altitudes lung damage adult respiratory distress syndrome

Question 60

Which hormone is produced in the hypothalamus?

Answer 60

ADH

Question 61

What is responsible for moving absorbed fat?

Answer 61

lymphatic system