Lecture 16 - Circulation Part 2 Flashcards Preview

FHB Exam 1 - Cardiovascular Physiology > Lecture 16 - Circulation Part 2 > Flashcards

Flashcards in Lecture 16 - Circulation Part 2 Deck (47)
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1
Q

What is pressure?

Name the following types of pressures:

  1. Pressure tending to distend a vessel
  2. Pressure differential between inflow/outflow
  3. Pressure caused by the height of a fluid column
A

P = F/A

  1. Transmural Pressure
  2. Pressure Gradient
  3. Hydrostatic Pressure
2
Q

What is the mean arterial pressure?

A

Average pressure existing in the AORTA and proximal arterial system during ONE cardiac cycle

3
Q

What are the components that make up Mean Arterial Pressure?

A

MAP = diastolic Pressure + 1/3 Pulse Pressure

4
Q

What are the 2 physiologic factors of BP? The 2physical?

A

Physiological:

  1. Cardiac Output
  2. Peripheral Resistance

Physical:

  1. Arterial Blood Volume
  2. Arterial Compliance
5
Q

What primarily determines systolic pressure?

A

CARDIAC OUTPUT

  • changed by autonomic nervous system
6
Q

What primarily determines diastolic pressure?

A

Total Peripheral Resistance

7
Q

How is TPR & Cardiac output regulated?

A

TPR:

  1. Autonomic control
  2. Local Metobolic (which overrides nervous control)
    - vasodilation/vasoconstriction

CO:
1. Autonomic Control

8
Q

How does arterial compliance affect systolic and diastolic pressures?

A
  • at LOW compliance

systolic INCREASES & diastolic DECREASES

  • created a large Pulse Pressure
9
Q

What are the 2 main determinants of TPR?

A
  1. Arteriolar Radius

2. BLOOD VISCOSITY

10
Q

Baroreceptors maintain arterial BP by continuously adjusting what 2 factors?

A
  1. HR

2. Peripheral Resistance

11
Q

How does the pulse pressure change with exercise?

A

WIDENS

  • more work for the heart, BUT transient wider pulse pressure is good during exercise because it strengthens the heart

(not the same as having this problem CONSTANTLY; transient is ok)

12
Q

What is sepsis?

A

massive vasodilation & diastolic drops out

  • if all vascular beds open up all at the same time & diastolic pressure drops out
13
Q

The following all decrease what?

  1. CHF
  2. Bradycardia
  3. Sepsis
A

BLOOD PRESSURE

14
Q

What determines arterial compliance?

A
  1. location in arterial vasculature,
  2. age
  3. blood volume
  4. sympathetic tone
  5. pregnancy
15
Q

As peripheral resistance increases, how does systolic and diastolic BP change? Which is affected more?

A

BOTH increase

  • diastolic is affected MORE (since TPR primarily affects diastolic BP & cardiac output affects systolic)
16
Q

The following are local or global responses to a decrease in Total Peripheral Resistance:

  1. Baroreceptor Reflex
  2. Hormonal (angiotensin, epinephrine)
  3. Sympathetic Activity (vasocontrict/vasodilate)
A

GLOBAL!!

17
Q

What are some local affects to increase TPR?

A
  1. Myogenic Response (muscle)
  2. Endothelium Meditated Regulation
  3. Local Metabolic Changes (O2, CO2, metabolites)
18
Q

Blood pressure relies on what 2 factors?

A
  1. Peripheral Resistance

2. Compliance

19
Q

At HIGH peripheral resistance is diastolic pressure high or low?

A

HIGH

  • relies on TPR
20
Q

Blood viscosity works to increase what?

A

Total Peripheral Resistance

21
Q

What 3 areas does the sympathetic system change in order to increase BP?

A
  1. Heart- increase HR - increase Cardiac Output
    - increase contractility
  2. Veins venoconstrict - increase Venous Return - increase Stroke Volume
  3. Arteries
    - vasocontrict
    - increase Total Peripheral Resistance
22
Q

What are 2 ways the heart increases Cardiac Output directly & by increasing stroke volume?

A
  1. Increase Heart rate

2. Increase contraction strength (which increases stroke volume)

23
Q

How does the venous system increase CO?

A
  1. Venoconstrict
  2. increase Venous Return
  3. Increase Stroke Volume
24
Q

How does the arterial system increase BP?

A
  1. Vasoconstrict
  2. increase Total Peripheral Resistance
  3. Increase BLOOD PRESSURE
25
Q

During exercise where is blood shunted/cut off?

A
  1. Shunted to skeletal muscle
    - heart
    - cutaneous (to sweat&cool down)
  2. Cut off to VISCERA
    - no pee/poo
26
Q

Does pulse pressure increase or decrease during exercise?

A

INCREASES

  • diastolic should decrease since TPR is decreasing
27
Q

How does Arteriovenous Oxygen changing during exercise?

A

IT IS INCREASING

28
Q

What occurs during anticipation of exercise?

A
  1. decrease parasympathetic nerve activity.
  2. increase sympathetic nerve activity.
  3. increased heart rate and myocardial contractility.
  4. continues throughout exercise
29
Q

What occurs as HR reaches a maximum value?

A

STROKE volume declines (reduced filling time)

  • but up until a point, HR increases contractility which increases Stroke volume & thus cardiac output
30
Q

During sympathetic vasoconstriction, where is blood shunted away from?

A
  • kidneys, skin, splanchnic regions & inactive muscle

cerebral, pulmonary, and cardiac unaffected

31
Q

During exercise, what happens to capillaries?

A

CAPILLARY RECRUITMENT,

active muscle capillaries open for max blood flow

32
Q

How is venous return increased? 3 ways

A
  1. sympathetic venoconstriction decreases venous compliance & shunts blood BACK to the heart

= INCREASE venous return

  1. Muscle Pump
  2. Respiratory Pump
33
Q

In anticipaion of exercise, what occurs in the oxyhemoglobin dissociation curve? What does this mean?

A
  • shifts RIGHT
  • more free O2 available for skeletal muscle (not holding to hemoglobin)
  • increase Arteriovenous Oxygen Difference
  • OXYGEN CONSUMPTION INCREASES
34
Q

Metabolites always cause what in the body? Is this a global or local control?

A
  • always cause VASODILATION

- LOCAL control which outcompetes the global vasoconstriction (on ACTIVE muscle)

35
Q

How do metabolites (adenosine, K+, CO2, and H+) change the local environment to cause vasodilation? How can they be used to break arrhythmias?

A
  • change in pH and changes the binding affinity of hemoglobin to oxygen
  • thus MORE free oxygen released to skeletal muscle
  • work on same channels as Acetylcholine to INCREASE K+ permeability, allowing it to leave the cell (hyprpolarizes, moving the diastolic depolarization slope away from threshold = slow down pacemakers)
36
Q

How can vasodilation be induced for people who cannot use the treadmill?

A
  • inject adenosine
  • see if VASODILATIOn occurs

(short half life)

37
Q

Should diastolic pressure decrease or increase with a decrease in TPR? What should usually occur during a stress test?

A

DECREASE

  • diastolic pressure should decrease
  • thus if it INCREASES then the arteries are not vasodilating
    = increase in after load
    (pathology)
38
Q

What usually overcomes during stimulation of both:

  1. Global Sympathetic
  2. Local Metabolic
A

LOCAL METABOLIC always overcomes global sympathetic

in areas that need it

39
Q

What are the 3 parameters of work?

A
  1. HR
  2. Contractility
  3. Afterload
40
Q

The heart & skeletal muscle VASODILATOR during exercise as a response to what?

A

respond to an INCREASE in WORK

  1. HR
  2. Contractility
  3. Afterload
41
Q

What is the only area that cannot increase O2 extraction?

A

the HEART

  • flow limitd organ, & only way to increase oxygenn is through
    1. Vasodilation
    2. Increase blood flow
42
Q

With enhanced O2 extraction during exercise, which direction does the oxygen dissociation curve shift? What happens to Arteriovenous Oxygen Difference?

A
  1. shifts RIGHT
    - so response is MORE sensitive to a change in O2/Co2
  2. AOD INCREASES
    since arteries taking up more oxygen and veins are giving it up
43
Q

Capillaries that open in skeletal muscle are a metabolic or local response?

A

METABOLIC response in skeletal muscle

  • capillary recruitment is due to an increase in FLOW (not metabolic)
44
Q

What are 2 important mechanisms that the Venous System relies on to increase Venous Return?

A
  1. Skeletal Leg Pump

2. Respiratory pump

45
Q

During exercise, what are the changes to the following

  1. Systolic Pressure
  2. Diasotlic Pressure
  3. Pulse Pressure
A
  1. Systolic pressure - INCREASES due to increased STROKE volume (sympathetics maintaining & raise Mean Arterial Pressure)
  2. Diastolic - relies on TPR
    - so can increase, stay constant, or decrease depending on type of exercise & mass of tissue
  3. PULSE PRESSURE WIDENS
    (since systolic pressure increases)
46
Q

What is the affect of weight lifting on

  1. TPR
  2. Mean arterial Pressure
A
  1. TPR is not decreasing (no vasodilation)
  2. MAP is increasing (not aerobic exercise)

ex: why older people can have a heart attack during weight lifting
(map increases, TPR is still high = not enough OXYGEN)

47
Q

What determines the MAP during exercise?

A

the type of exercise