Cardio Flashcards
What are the primary functions of the CV system?
Supply
- O2
- Fuel
- Heat (when needed)
Remove
- Metabolic byproducts
- Heat
What are five priorities of the CV system
- Maintain Homeostasis
- Deliver Adequate Cardiac Output
- Maintain Blood Pressure
- Supply Nutrients as needed
- Allow exchange in capillary beds
Name the 7 major physical components of the CV system
Heart
- Right and Left Atrium, and Right and Left Ventrical
Pulmonary Artery and Vein
Aorta
Arteries
Tissues
Systemic Veins
Vena Cava
Describe the average normal blood pressure at the following sites
Right Atrium
**Right Ventrical **
Lungs
Left Atrium
**Left Ventrical **
Aorta
Capillaries
**Vasculature **
Remember that blood pressure is related to cross sectional volume and flow speed. All in mmHg
RA - 25/2
RV - 25/10
Lungs - 8
LA - 5/3
LV - 120/3
Aorta - 120/80
Capillaries - 20
Vasculature - 17
What is the relationship between Pressure, Cardica Output (flow) and Resistance
A modification of Ohms Law
dP = Flow * R
You can cover any one value above to see how the other two relate. ie. Cover F to see that it = P/Q
Show how to calculate the total peripheral and pulmonary resistance.
Average cardiac output in an adult is 100ml/sec
And the average change in BP is about 100 mmHg
So from R = dP/F we get
100mmHg/100ml/sec
This is defined as
1 Peripheral Resistace Unit
note: This is the difference in BP from the Aorta to the Right Atrium. Pulmonary pressure is the mean pulmonary pressure - Left Atrial pressure
What is the percentage of total blood volume for each of the following?
Venus System
Heart & Lungs
Arteries
Capillaries
Approximate percentages. The venus system can be used as a reserve in the event of blood loss
Venus ≈ 70%
Heart and Lungs ≈ 15%
Arteries ≈ 10%
Capillaries ≈ 5%
Describe what happens to blood velosity, compared to the total cross sectional area of the vasculature as blood moves from the Aorta to the Vena Cava
Velocity (starting on left) drops off at the capillaries before picking up at the veins. TCA is low until the capillaries, where it spikes.
What does sympathetic nervous system activation do to the heart?
Releases Norepi
- Increases Na+ and Ca++ permeabilities
- Decreases K+ permeabilities
These promote depolarization, increasing heart rate.
What are the 4 heart sounds
S1 - Atrio ventricular valve closure
S2 - Aortic and Pulmonary (semi lunar) Valve Closure
S3 - Vibration with rapid ventrical filling due to turbulence, -normal in young health people.
S4 - Rapid Atrical contraction against stiff ventricular walls
Define Local Control of Blood Flow
Is the ability of a tissue to modulate its own blood flow independent of neural influences.
This topic encompasses
Basal Tone - Vasoconstrivtive tone independent of Sympathetic innervation
Blood Flow Autoregulation - maintaining flow during change in perfusion pressure
Active or Functional Hyperemia
Reactive Hyperemia
What are the majore theories that describe the mechanics of local contol of blood flow
Basal Tone
Blood Flow Autoregulation
Active or Funtional Hyeremia
Reactive Hyperemia
Define Autoregulation and list assuptions used by that definition
A tiusses abilitiy to maintain constant blood flow in the face of changing perfusion pressure.
Assumes - Metabolic demand is constant, and there is no Neural influence.
Brain Heart and Kideny are good at this
Myogenic Theory - Vessels sense strech and contract via reflex
Law of LaPlace T = P X r/2h
Metabolic Theory - Metabolite are produced to change flow as needed.- if metabolites are washed away by high flow, the vessel constricts, not enough flow and they vasodilate, creating a feedback loop.
Define Active Hyperemia and assumptions made in this definition.
Seen when the functional activity of a tissue or organ is increased.
Assumes blood pressure is constant
Tissues modifiy their vessel radius to increase or decrease their flow from a stable pressure source to meet metabolic needs.
Ths describes mussles under exercise conditions.
Define Reactive Hyperemia, and assuptions used in that definition
Observed during reperfusion of a tissue, to makeup an O2 deficit.
keeping in min the O2 ratio theory where
O2 demand/O2 supply
occulsion makes the ratio move towards infinity, triggering a flood of vasodilitative metabolites.
Define Negative feedback and how it relates to local control
The feedback loop maintains homeostatis
