Blood pressure

Question 1

Define blood pressure

Answer 1

pressure exerted by the blood on the wall of a blood vessel -mmHg

Question 2

Define systolic blood pressure

Answer 2

highest pressure, measured when the LV is contracting and expelling blood into the aorta

Question 3

Define diastolic blood pressure

Answer 3

lowest pressure, measured when the LV is relaxing and blood is flowing into peripheral blood vessels

Question 4

What is blood pressure measured with/

Answer 4

Sphygmomanometer

Question 5

Define pulse pressure

Answer 5

difference between systolic and diastolic blood pressure and can be felt at the arteries

Question 6

What is the pulse pressure equation?

Answer 6

pp= SBP- DBP

Question 7

What is textbook normal BP?

Answer 7

120/80mmHg

Question 8

Define mean arterial pressure

Answer 8

pressure that propels blood through tissues.

-equivelant to DBP +1/3 of PP

Question 9

Define peripheral resistance

Answer 9

vessel diameter and length

eg, vasoconstriction increases BP
vasodilation decreases BP

Question 10

What determines BP?

Answer 10

-Cardiac ouput
-peripheral resistsnce
-blood volume
-blood viscosity

Question 11

How does blood volume effect BP?

Answer 11

increased blood volume increases BP
decreased blood volume, decreases BP

Question 12

How does blood viscosity effect BP?

Answer 12

thicker blood is harder to pump, increases BP

Question 13

How does cardiac output determine BP?

Answer 13

more blood the heart pumps out, the higher the BP

Question 14

Whats the relationship between vasodilation and BP?

Answer 14

-widening blood vessel lumen via relaxation of the muscle wall
decrease BP

Question 15

Whats the relationship between vasoconstricion and BP?

Answer 15

-narrowing blood vessel lumen via constriction of muscle wall, increases BP

Question 16

Define vascular tone

Answer 16

at rest it is the state of constriction of the vessel relative to its maximally dilated state

Question 17

Name some intrinsic factors of BP

Answer 17

-myogenic mechanisms
-endothelilal factors eg Nitric oxide
-local hormones
-metabolic by products
-hypoxia

Question 18

Name some extrinsic factors of BP

Answer 18

-sympathetic nerves
-circulating hormones

Question 19

Describe the neutral control of BP

Answer 19

-cerebral cortex
-limbic system and thalamus
-hypothalamus
-pons
-medulla oblongata
-spinal cord T1-L2
-Spinal cord s2-s4

Question 20

What is Marey’s law?

Answer 20

there is an inverse relationship between BP and HR

Bp increases, HR decreases
BP decreases, HR increases

Question 21

Describe what happens to BP during excersise

Answer 21

-increased muscle contraction
-increases skeletal muscle pump
-increased blood flow back to heart
-increased rate and depth of respiration increases blood flow into the thoracic cavity (inspiration) and blood entering the heart. (expiration)

Question 22

Describe the bainbridge reflex

Answer 22

-blood returning to the heart enters the RA
-RA contains stretch receptors that detect increased atrial filling
-stretched atrial walls initiate a bainbridge reflex
-results in an increase in HR to clear extra blood

Question 23

Define frank starling’s law of the heart

Answer 23

the force of ventricular contraction is determined by the length of the cardiac muscle fibres

Question 24

Describe the events that occur in relation to frank starling’s law

Answer 24

-more blood enters ventricles from atria
-ventricles fill more and ventricular muscles are streched more
-greater the stretch = greater the force of ventricle contraction
-greater force of contraction= greater stroke volume

Question 25

Define stroke volume

Answer 25

amount of blood ejected from the ventricle during one contraction

Question 26

Define end diastolic volume

Answer 26

amount of blood in the ventricle at the end of diastole

Question 27

Define end systolic volume

Answer 27

amount of blood in the ventricle at the end of systole

Question 28

what is the Stroke volume equation?

Answer 28

SV = EDV- ESV

Question 29

What is preload?

Answer 29

the degree to which the ventricular musle is stretched just before contracting

Question 30

What is afterload?

Answer 30

The pressure that the ventricles must overcome to push the blood through the SLV as the ventricles are contracting

Question 31

How is the renin-angiotensin aldosterone system in initiated?

Answer 31

decreased blood flow to the kidnet, results in an increase in blood volume and stimulates vasoconstriction

Question 32

Describe what happens to BP during excersise

Answer 32

-increase in HR and SV increases Q
-increase in Q, increases BP
-designed to meet increased demands of muscles- increased O2 supply, glucose and removal of waste products
-increased muscle activity is a stimulus detected by proprioreceptors
-stimulated proprioreceptors cause an increase in HR, SV, Q and BP

Question 33

What happens when chemoreceptors detect acidosis?

Answer 33

-increased cardiac output
-increase respiratory rate to help the body achieve a steady state

Question 34

What factors effect mean arterial pressure?

Answer 34

-increased activity of muscular pump and respiratory pump
-decreased released of ANP
-fluid loss from hermorage or sweating
-crisis stressores
-bloodborn chemicals
-dehydration/high haematocrit
-increased body size

Question 35

What factors are involved in cardiac ouput regulation?

Answer 35

-excersise
-decreased HR
-bloodborn epinephrine, thyroxine , ca2+
-excersise

Question 36

What factors enhance cardiac output?

Answer 36

-excersise
-decreased BP activates cardiac centres in medulla

Question 37

How does a rise in BP result in a decreased HR?

Answer 37

-baroreceptos detect a rise in BP
-impulses sent to medulla
-more impulses sent to the SAN via PSNS
-Decrease in frequency of impulses from SAN
-decreased HR