Controlling the heart and blood pressure

Question 1

Cardiac output

Answer 1

How much the heart pumps out/ how much is in the pipes

Question 2

Which ventricle generates the systemic blood pressure?

Answer 2

The left ven, generated at iso where V doesnt change but P is built to surge blood

Question 3

What is the imporant determinant of blood flow

Answer 3

Mean arterial blood pressure

Question 4

Where is blood P is highest?

Answer 4

The arteries, oscillatory pattern

Question 5

Where does blood P fall and oscillatory nature reduced?

Answer 5

steeply across
the arterioles, capillaries, and
venules

Question 6

Where is blood P low

Answer 6

Veins

Question 7

Where is blood P the lowest

Answer 7

The right atrium

Question 8

What creates the driving force of blood flow

Answer 8

The diff. in P of arterial and venous sides, not absolute P value

Question 9

What is Haemodynamics?

Answer 9

How blood flows through a single vessel

Question 10

Flow

Answer 10

Pressure diff/resistance

Q = ∆P/R

Question 11

More flow is caused by…

Answer 11

Greater P difference/ lesser resistance

Question 12

∆P =

Answer 12

MAP - 0 = MAP

Question 13

MAP =

Answer 13

Q X R

Question 14

What do we want to keep steady?

Answer 14

The pressure, so flow is steady

Question 15

Blood flow in:

Answer 15

– fills arteries
– increases arterial blood volume
– raises arterial pressure.
– Ventricular contraction
– Ejection of blood
– CARDIAC OUTPUT

Question 16

What determines flow out?

Answer 16

RESISTANCE

Question 17

Blood flow out

Answer 17

– drains arteries
– decreases arterial blood volume
– lowers arterial pressure.
Capillary flow
– Controlled by resistance of the arteries

Question 18

• Arterial blood volume and pressure are determined by:

Answer 18

– balance between blood flows “in” and blood flow out

Question 19

• Balance flow in / out determines
  pressure

Answer 19

– Increase cardiac output (increase inflow)
– Increase resistance (decrease outflow)
– Increase arterial volume and Pressure

Question 20

MAP = CO x TPR

Answer 20

Arterial Pressure = Cardiac output x Total Peripheral Resistance

Question 21

Factors that determine how much blood pumped out

Answer 21

-BPM
-Size of “squirt” i.e Stroke Volume

Question 22

CO = SV x HR

Answer 22

Cardiac Output = Stroke Volume x Heart Rate
(L/min) (L/beat) contraction strength (beats/min)
contraction speed

Question 23

Stroke volume of a healthy heart

Answer 23

70mL per beat

Question 24

Healthy heart rate

Answer 24

60-80 bpm

Question 25

Failing heart stroke volume

Answer 25

40mL/ beat

Question 26

Failing heart rate

Answer 26

120 - 130 bpm

Question 27

How much blood in our body

Answer 27

5L

Question 28

What do we wanna keep steady as it drives the system?

Answer 28

MAP

Question 29

Is MAP tightly controlled?

Answer 29

Yes, it has a narrow range

Question 30

What is TPR?

Answer 30

Blood vessels vascular resistance

Question 31

System that received info and releases info about BP in…

Answer 31

The brain (CNS), coordinated at the brainstem

Question 32

In/Output from brain

Answer 32

– Afferent input from both the CNS and ‘periphery’ (baroreceptors)
– Efferent output to heart and vessels

Question 33

What are baroreceptors?

Answer 33

Blood pressure sensors

Question 34

Where are Baroreceptors located?

Answer 34

Arch of Aorta

Question 35

What DO bARORECEPTORS DO?

Answer 35

-They are tonically active
-They dont turn on or off but have resting activity that ^ or decreases –> relayed to cardiovas pasrt of brainstem where decision is made to regulate the BP

Question 36

Two neural controls of cardiac output

Answer 36

Sym and Parasym

Question 37

Parasym

Answer 37

• Brake / reducing output
• When BP is too high, need to reduce
• Vaugus nerve reduces by affecting the SA and AV nodes i.e the pacemakes and “pause” nodes

Question 38

Sym

Answer 38

• Accelerator
• When BP too low
• Sym cardiac nerves ^ by affecting ugus nerve reduces by affecting the SA and AV nodes i.e the pacemakes and “pause” nodes, (affects HR) + ven uscles to pump harder (affects SV)

Question 39

Baroreflex

Answer 39

We dont have to think about our heartbeat