Cardiovascular Normal Function Part 2

Question 1

Closed Circulatory System

Humans (all vertebrates), blood never ____ vessels, movement of gases, O2, CO2, glucose, fatty acids move through ____ and exchage at ____ level

______: tiny arteries that provide blood flow to capillary beds throughout the body

_____ _____: site of exchange between blood and tissue

______: tiny veins that drain blood back to right side of heart

Are THICK bc are lax, ___ resistance/non ______ vessels

Answer 1

leaves, diffusion, tissue

Arterioles

Capillary Beds

Venules

low resistance, non-muscular

Question 2

Flow Dynamics

F = ►P/R

• F =
• ►P =
• R =

Answer 2

• Flow rate through vessel
• Pressure gradient
• Resistance of blood vessel

Question 3

Flow Dynamics Notes

• Flow rate = v_____ per t____
• Pressure gradient = P_____ pressure
• Pressure gradient/Resistance = _______ related

Resistance to flow comes from 2 things

• _______: (thickness) of blood determined by ______: ratio of cells to plasma
  
  • ​High viscosity =
• ______ of Vessel*: relationship between r_____ and r______ is ______ (small change in radius produces big changes in resistance

Answer 3

• volume per time
• perfusion
• inversely
• Viscosity, Hematocrit
  
  • ​Lot of cells, Low plasma
• Diameter, radius and resistance
  
  • ​Exponential

Question 4

Radius vs. Resistance

• Smaller Radius -> ______ Resistance -> ______ in flow
• Bigger Radius (______) -> _____ Resistance -> ____ in flow

In the picture, the diameter increases by __x but the flow increases by ___x

Answer 4

• higher -> decrease
• Dilation -> lower -> increase

2x diameter -> 16x flow

Question 5

Arteries

The arteries are designed to perform two major duties:

1. Fast _____ from heart to tissues (____ diameter vessels)
2. _____ pressure and provide _____ force for flow when heart is resting (elastic walls)

Connective tissue layer ______ and _____ fibers

Underlying _____ _____

External _____ _____ covering

Answer 5

1. transport (large)
2. Store, driving force

collagen and elastin

smooth muscle

connective tissue

Question 6

Arteries as a Pressure Reservoir

Pressure transfers from ventricular _____ -> ____ on aortic wall -> perfusion pressure during diastole when aortic wall ______

Answer 6

contraction -> stretch -> rebound

Question 7

What is happening in this picture?

The energy is transferred into?

Answer 7

Driving Force

Question 8

Arterial Blood Pressure

Blood Pressure - ____ of blood against vessel wall

Compliance and Distensibility

• Arteries compliance?
• Veins compliance?

Notes

• BP = indirectly measuring _____ pressure by measuring ____ artery pressure
• Systolic = ____ arterial pressure (generated by systolic contraction of ventricles)
• Diastolic = ____ pressure of arteries (generated by how healthy artery walls are and blood volume)

Answer 8

force

• not very compliant
• very compliant
• aortic, brachial
• peak
• resting

Question 9

Arterial Blood Pressure

1. Systolic: ____ average
2. Diastolic: ___ average

(1): Difference between systolic and diastolic pressure

• represents the potential for _____
• Lower pulse pressure = less ____ ventricles can push into aorta

(1): constant perfusion pressure that is present in the arteries no matter what phase your heart is in

• ADEQUATE MAP = _____ OF ______
• weights _____ pressure > _____ pressure bc your BP spends more time closer to diastolic than it does to systolic
• MAP = ____ + _____

Answer 9

1. 120
2. 80

Pulse Pressure

• Perfusion
• blood

MAP

• PERFUSION OF ORGANS
• diastolic > systolic
• Diastolic pressure + 1/3 pulse pressure

Question 10

Manual BP

Pump up bladder until you lose ____ pulse: this represents when cuff pressure is just ____ systolic pressure (just harder than the peak pushing pressure of that artery)

Answer 10

lose radial pulse -> above SBP

Question 11

Korotkoff Sounds

• Green line = Cuff Pressure
• Tapping sounds = _____ blood flow

1. ___ radial pulse left
2. First tap =
3. Last tap =

• Both numbers when taking manual BP are ________ (slightly less than systolic and diastolic)

Answer 11

• turbulent

1. No
2. Comes from force of blood that comes through the squeezed brachial artery that represents cuff pressure just below systolic pressure
3. When cuff pressure falls just below diastolic pressure

• ​underestimations

Question 12

Oscillation of Pressures through the Vascular Tree

Gradual ____ of MAP through arteries, arterials, veins promote movement of blood in that _____ way

• Left ventricle:
• Systemic arteries:
• Arterioles:
• Capillaries and Veins:

Answer 12

Decline

• 0-120
• 80-120
• starts to lose pulse pressure
• completely looses pulsatile nature

Question 13

Arterioles

• Supplies Organs
  
  • Arteriole walls very simplified compared to arteries -> very ____ connective tissue**, still has ____ _____ covering
• Diameter changeable

1. ______ distributes CO based on current _____: “_______” to blood entering an organ
2. Regulates arterial _____ _____: bc has signficant ability to ____ and ____ -> effects overall _____ in the system

Answer 13

• Supplies Organs
  
  • little connective tissue**, smooth muscle
• Diameter changeable
  
  • Variably distributes CO, demands, “gatekeepers”
  • BP: constrict and dilate -> resistance

Question 14

Arteriole Tone

What Factors Cause Vasoconstriction or Vasodilation

Normal Arteriolar Tone =

Produced by:

1)

2)

Answer 14

Resting diameter of arterial produced by basic properties of muscles that surround arterioles and baseline SNS output

1) Myogenic activity - elastic property of the muscle tissue

2) Baseline sympathetic input

Question 15

What Factors Cause Vasoconstriction or Vasodilation?

Factors fall into two general categories:

Intrinsic Factors (1)

Extrinsic Factors (2)

Answer 15

Local Factors

Neuronal or Hormonal Factors

Question 16

Intrinsic Local Control

= Changes with ______

1. Chemical (2)
2. Physical (2)

Answer 16

Tissue

1. Chemical
   
   1. ​Local metabolic changes
   2. Histamine release
2. Physical
   
   1. ​Local application of heat or cold
   2. Myogenic response to stretch

Question 17

Local Control - Chemical Factors

1. Local Metabolic Changes (4)

• Vasoconstriction
  
  • O2 =
  • CO2 =
  • Acidity =
  • Adenosine =
• Vasodilation
  
  • O2 =
  • CO2 =
  • Acidity =
  • Adenosine =

Answer 17

O2, CO2, Acidity, Adenosine

• Vasoconstriction
  
  • Increased
  • Decreased
  • Decreased
  • Decreased
• Vasodilation
  
  • Decreased
  • Increased
  • Increased
  • Increased

Question 18

Local Metabolic Changes Notes

Free ____ increases whenever you are consuming ATP

______ Cells: Critical player in local control, cells that directly face the blood and sense changes in O2, CO2, Acidity, Adenosine

Endothelial Cells will Release what during

• High Metabolic Activity (1)
• Low Metabolic Activity (1)

Answer 18

Adenosine

Endothelial Cells

• Nitric Oxide: gas that acts on smooth muscle to dilate vessel when tissue is very metabolically active (low O2), so dilation will dilate to increase perfusion and O2 delivery to tissue
  
  • EDRF = Endothelial Relaxing Factor (first name for NO)
• Endothelin: substance that goes next door to smooth muscle to cause vasoconstriction -> shunts blood to somewhere else where is most needed

Question 19

Extrinsic Control

Includes both _____ and ______ influences

Most important is the effect of?

Sympathetic nerve fibers supply arteriole smooth muscle everywhere but the brain

• Increased activity = generalized ______
• Decreased activity = generalized ______

Releases what hormone? - onto what receptors?

Helps regulate _____ _____

Answer 19

neural and hormonal

Sympathetic nervous system

• vasoconstriction
• vasodilation

Norepi -> alpha-adrenergic receptors

Blood pressure

Question 20

Extrinsic Control Notes

Increased sympathetic activity

• Total peripheral resistance?
• CO = HR x SV -> HR? SV?
• Vaso_____ on vein -> increases venous ______ -> increase end ____ volume -> more ___ volume

Generalized vasoconstriction is the NET effect - Think Fight or Flight (Sympathetic Response)

• Specific effect that sympathetic stimulation has to a particular arterial bed depends on ____ that arterial bed resides
• Arterioles that perfuse smooth muscle and bronchioles have ____ receptors
  
  • Norepi binds to beta receptors causes = ______
• Arterioles that perfuse nearly all other organs have ____ receptors
  
  • Norepi binds to alpha receptors causes = ______

Answer 20

• TPR increases
• HR and SV increases
• constriction -> return -> diastolic volume -> stroke
• where
• Beta
  
  • Vasodilation (allows you to RUN/FLEE)
• Alpha
  
  • Vasoconstriction (blood flow shunts away from GI/liver/kidneys)

Question 21

How does Arteriole Diameter relate to Blood Pressure?

F = ►P/R

Cardiac Output (CO) =

Mean Arterial Pressure (MAP) =

Total Peripheral Resistance (TPR) =

CO = MAP/TPR or MAP = CO x TPR therefore..

TPR most influenced by _____ resistance

Answer 21

CO = Flow

MAP = ►P

TPR = R

Arteriolar Resistance

TPR is a function of blood viscosity (hematocrit) AND overall arterial constriction vs. dilation

Relationship between CO and MAP - positive association

So depending on what arterioles are doing TPR goes up and down which causes our MAP to go up or down

Question 22

Constant Pressure in pipe (MAP)

High resistance = ___ flow

Moderate resistance = ___ flow

High resistance = ____ flow

Beakers = Organs, Outlets = Arterioles

Answer 22

No

Moderate

High

Question 23

Distribution of CO Rest vs. during Exercise

1. Total CO?
2. Blood flow to Skeletal Muscle?
3. Blood flow to Heart?
4. Blood flow to Brain?
5. Blood flow to Skin?
6. Blood flow to Organs?

Answer 23

1. Total CO expands
2. Increases by over 1000% (5L/min -> 12.5L/min)
3. Increases
4. Fixed amount, doesn’t change
5. Gets more (so it can dissipate heat so our core temp doesn’t go up)
6. Gets LESS

Question 24

Hormonal Influence on Arteriolar Diameter

______ Activity

Hormones (2)

What gland does it act on?

Answer 24

Sympathetic

Epinephrine and Norepinephrine

Adrenal Gland (Cortex and Medulla)

Question 25

Hormonal Influence on Arteriolar Diameter ## Footnote 1. **Epinephrine** * **​​**Greater affinity for what receptor? * Effect? 2. **Norepinephrine** * **​​**Greater affinity for what receptor? * Effect?

Answer 25

* Beta receptors located on arteries that perfuse skeletal muscle and bronchioles * Vasodilation -\> ability to run/flee * Alpha receptors on organs * Vasoconstriction -\> shunts blood away from organs

Question 26

Hormonal Influence on Arteriolar Diameter ## Footnote **(2)** That both cause **Vasoconstriction**

Answer 26

**Vasopressin** (Water balance) **Angiotensin II** (Plasma volume-Sodium)

Question 27

Capillaries ## Footnote The sites of exchange of all material between blood and tissues * Highly adapted for \_\_\_\_\_\_\_\_ * Diffusion ______ is minimized * _____ of diffusion barrier is minimized * Tremendous ______ \_\_\_\_\_\_\_ available for diffusion (600m2) * Blood velocity ______ through capillary beds

Answer 27

* Diffusion * distance * Thickness * Surfance Area * Slows Most of the time the mechanism of exchange is **simple diffusion** "Capillary beds (bodies exhibit) are so dense, so many, huge surface area, etc" Speed of RBC traveling through capillaries slows down -\> to increase opportunity for exchange

Question 28

Cross-Sectional Area and Velocity of Capillaries ## Footnote What happens to these as it moves toward the Capillary Beds * **Cross Sectional Area (cm2):** * **Velocity (mm/sec):** * **Flow Rate (L/min):** * ​Equation: Flow rate = __ x \_\_

Answer 28

* Increases dramatically (more area available for diffusion) -\> which also contributes to slowing blood velocity * Slows so more opportunity for exchange * NEVER changes by 1. Cross sectional area of arteries and veins is the same 2. As cross sectional area inreases in capillaries, velocity goes down * total cross sectional area x velocity

Question 29

Capillary Structure ## Footnote **(1):** Little gaps between endothelial cells that allows for diffusion * They make the capillaries very **\_\_\_\_\_\_** which is unlike the capillaires in the ____ that make up the \_\_\_\_ * What can pass through? * What cannot pass through?

Answer 29

**Pores** * **leaky,** brain, BBB * Glucose, Ions, Fluid * Plasma proteins and cells (RBC, platelets, WBC)

Question 30

Transport Across Capillary Wall ## Footnote * (2) = Lipid soluble (nonpolar) substances that pass through _endothelial cells_ * (4) = Small, water-soluble substances that pass through _pores_ * (1) = Cannot cross the capillary wall * (1) = Moved across by vesicular transport

Answer 30

* O2, CO2 * Na, K, glucose, AA * Plasma proteins (Albumin) are retained * Exchangeable proteins (like antibodies use endo/exocytosis)

Question 31

Capillary Bed Components ## Footnote **(1):** slightly larger than capillary vessels and represents vessels with a smaller cross sectional area than the capillaries that surround them **(1):** little bands of smooth muscle that lie in between capillary vessels and metaarterioles so that when they're constricted most blood flows through the meta-arteriole * What does this mean for tissue if blood is just going through metaarterioles? * **Tightness of Sphincters is Controlled by Local Metabolic Activity of that Tissue** * **​**_High metabolic need_ -\> want more blood flow through _____ -\> causes precapillary sphincters to \_\_\_\_\_ * _Low metabolic need_ -\> want more blood flow through ____ so causes precapillary sphincters to \_\_\_\_\_, so blood can do what?

Answer 31

**Meta-arterioles** **Precapillary Sphincters** * **Less opportunity for exchange but will be able to get from arterioles to venules faster** * ​capillaries, RELAX * metaarterioles, CONSTRICT (so blood can quickly return and be sent somewhere else)

Question 32

Transport Across Capillary ## Footnote Vast majority of time exchange is through? In this picture what uses a carrier mediated transport?

Answer 32

Simple diffusion Glucose

Question 33

Purpose of Bulk Flow ## Footnote **Capillary Bulk Flow:** ______ PROCESS to REGULATE DISTRIBUTION of ____ between _____ and ______ components * **(1):** NET movement into capillary * **(1)**: NET movement out of capillary * **(1):** _Pushing pressures_ * (2) * **(1):** _Pulling pressures_ * _​_(2) High metabolic activity -\> blood flows through capillary beds -\> net \_\_\_\_\_\_\_ Low metabolic activity -\> low capillary blood pressure -\> net \_\_\_\_\_\_\_

Answer 33

PASSIVE, ECF, Plasma (intravascular) and Interstitial * **Reabsorption** * **Ultrafiltration** * **Hydrostatic Pressure** * **​Interstitial hydrostatic pressure** (reabsorption) * **Capillary blood pressure** (ultrafiltration) * **Oncotic Pressure** (exerted by plasma protein (albumin)) * **Interstitial Oncotic Pressure** (ultrafiltration) - usually 0 bc no albumin * **Plasma Oncotic Pressure** (reabsorption)\*\*\* stable in a normal human, deficiency from starvation/liver failure -\> ascites ULTRAFILTRATION REABSORPTION

Question 34

Venous System ## Footnote **\_\_\_\_\_\_ Vessels** **Blood \_\_\_\_\_\_** * **Highly _____ and Highly \_\_\_\_\_** bc not much smooth muscle in their walls-\> _____ readily when blood enters * Therefore often described as our **Blood \_\_\_\_\_\_** * \_\_% of blood in systemic veins at rest * When we need, all we have to do is ______ stimulate them to \_\_\_\_\_/become \_\_compliant and blood will be forced to move onto heart increasing venous return * Total Blood Volume vs. ______ Circulating Blood Volume

Answer 34

**Capitance** **Reservoir\*** * **Compliant, Capitance,** accomodate * **Reservoir** * **​**64% * sympathetically, constrict, non * Effective

Question 35

Veins ## Footnote **(1):** Volume of blood that the veins can accommodate **(1):** Volume of blood entering each atria from the venous vessels Factors tht influence venous return 1. _______ induced venous vasoconstriction 2. Skeletal ______ activity 3. Effects of venous \_\_\_\_\_ 4. R\_\_\_\_\_\_ activity 5. Cardiac s\_\_\_\_\_\_

Answer 35

**Venous Capacity** **Venous Return** 1. Sympathetically 2. Muscle - when i contract mucles in my legs, i milk blood up to heart (works bc veins have valves which make blood move in one direction towards heart) 3. Valves 4. Respiratory - pressure in thoracic cavity diff in pressure compared to abdominal pressure 5. Suction

Question 36

Sympathetically Induced Venous Vasoconstriction ## Footnote Sympathetic Activity -\> ______ Compliance -\> _____ Venous Return

Answer 36

Decreased Compliance -\> Increase Venous Return

Question 37

Skeletal Muscle Activity ## Footnote **Orthostatic Hypotension/Syncope** happens bc? * _______ Venous Return * _______ CO * _______ MAP

Answer 37

blood pools in lower extremities when standing not enough CO for MAP/perfuse brain - so trick is to contract muscle in legs occasionally * Decreased * Decreased * Decreased

Question 38

Effect of Venous Valves on Venous Return ## Footnote **Open venous valve:** **Contracted skeletal muscle:** **Closed venous valve:**

Answer 38

Permites blood flow of blood toward heart Pushes blood both ways Prevents backflow of blood

Question 39

Effect on Respiratory Activity on Venous Return ## Footnote Pressure in thoracic cavity compared to abdominal and atmospheric pressure is?

Answer 39

Less pressure in thoracic cavity encourages movement of blood to heart as it gets closer to diaphragm

Question 40

Effects of Cardiac Sunction on Venous Return ## Footnote The heart plays a role in its own filling Ventricles contract -\> atrial volume increases -\> _____ pressure -\> enhances venous \_\_\_\_\_\_ Ventricles relax and expanding in volume -\> enhanced ventricular \_\_\_\_\_

Answer 40

negative pressure -\> enhances venous return filling

Question 41

Blood Pressure ## Footnote \_\_\_\_ is the main driving force in supplying blood to tissue * Too low = * Too high = * MAP = ___ x \_\_\_

Answer 41

MAP * inadequate perfusion * increased workload of heart MAP = **perfusion pressure** must maintain adequate MAP -\> but if it gets too high ends up increasing workload of heart and causes heart problems

Question 42

What Determines TPR? ## Footnote (2) Determined by (2) factors

Answer 42

**Blood Viscosity (hematocrit)** **Arteriolar Radius** * Local factors: skeletal muscle activity, general metabolic activity * Extrinsic factors: sympathetic nervous activity (epi and hormones like vasopressin, angiotensin)

Question 43

What Determines CO? ## Footnote (2)

Answer 43

HR: slowed by PNS, sped up by SNS SV: effected directly through sympathetic nerve or enhancment of venous return

Question 44

Control of MAP ## Footnote Control systems for MAP can be divided into two categories: 1. \_\_\_\_-term regulation = 2. \_\_\_\_-term regulation =

Answer 44

1. Short term = **Baroceptor Reflex** 2. Long term = **Renal System** by regulating plasma volume through RAAS

Question 45

Baroceptor Reflex ## Footnote Control BP on a ___ to ____ basis by measuring what? **2** locations - neural signals to?

Answer 45

moment to moment, constantly measuring stretch on artery wall **Aortic Arch baroceptor** **Carotid Sinus baroreceptor** CV control center in medulla

Question 46

Baroreceptors Reflex Firing Rates ## Footnote * When BP is normal: * When BP is increased: * When BP is decreased: Why only short term regulation?

Answer 46

* normal firing rate * INCREASE firing rate * DECREASE firing rate Bc they adapt/v sensitive to any change in BP -\> if elevated BP is sustained, baroceptors will adapt and firing rate will go back to normal, they don't remember what BP was like more than a few min ago

Question 47

Baroreceptor Reflex ## Footnote Baroceptors sense change and signals CV center in _____ -\> medulla increases ____ nerve activity to __ node in heart -\> **\_\_\_\_\_\_ HR** -\> decreasing HR will decrease ___ -\> decreased \_\_\_\_ Adjusting __ is the big step

Answer 47

medulla -\> vagus, SA -\> **Decrease HR** -\> CO -\> MAP HR

Question 48

Baroreceptor Reflex Outputs (example)-Responding to INCREASED MAP ## Footnote Not only do we adjust HR but we affect level of _____ stimulation to arterioles and veins to cause constriction or dilation within vessels ^PNS = Decreased SNS =

Answer 48

sympathetic = decrease HR -\> decrease CO -\> decrease BP = decrease HR -\> vasoconstriction of arterioles and veins -\> decrease BP

Question 49

Long term Regulation of BP \_\_\_\_\_ Influences in Plasma volume * ____ Mechanism * _____ output * _____ balance When BP is too high -\> _____ plasma volume When BP is too low -\> _____ plasma volume

Answer 49

Renal * Thirst * Urine * Salt Decrease Increase