Exam 2 Cardiac and Respiratory Flashcards
What is the percentage of blood volume in the heart?
7-10%
What is the percentage of blood volume in the arteries?
13%
What is the percentage of blood volume in the arterioles/capillaries?
7%
What is the percentage of blood volume in veins?
64%
What is the percentage of blood volume in the pulmonary circulation?
9%
If Blood Pressure is increased, what is the physiological response?
- Vasodilation of the arterioles
- Decreased heart rate and contractility
If blood pressure is decreased, what is the physiological response?
- Vasoconstriction of the arterioles
- Increased heart rate and contractility
Hematocrit of blood related to ____
viscosity
There is an inverse relationship between cross sectional area and ___.
velocity
According to Ohm’s Law, with a decrease in BP, what will happen?
There will be a decrease in CO, HR and Resistance
According to Ohm’s Law, with an increase in BP, what will happen?
There will be an increase in CO, HR and Resistance
Blood viscosity is mostly determined by ____.
The Hematocrit
Hematocrit is the ratio of ____
red blood cells volume to the total blood volume
The higher the hematocrit, ____
the greater the viscosity of the blood
Viscosity of plasma is ____
about 1.8
Viscosity of the whole blood may change from ___
3 to 5
_____ is the most important factor affecting blood flow resistance.
Radius of the blood flow
The length of blood vessels changes only during _____.
individual vasculature growth. Under normal physiological conditions length is constant.
Laminar Flow
- smooth tubes
- low rates of flow
- greatest flow in the center of the tube
- close to zero near the vessel wall
- flow directly proportional to pressure (linear relationship)
- angle of flow is less than 25o
Turbulent Flow
- rough tubes
- high velocity of flow
- flow through bends >25o, narrowing, and orifices
- resistance to flow is higher during turbulence
- flow - pressure relationship (nolinear relationship )
Reynolds Number
indicates conditions when flow changes from laminar to turbulent
Reynold’s Number is directly proportional to ____
fluid velocity, fluid density, and tube diameter
Reynold’s Number is inversely proportional to ____
fluid viscosity
Reynolds numbers less than 2000 flow is ___
laminar
Reynolds numbers 2000-3000 flow is _____
unstable (laminar/turbulent)
This is the most common flow in physiological areas of the body.
If Reynolds number is more than 3000, the flow is ___
turbulent
Turbulent flow in the body is a predisposing factor of ____
thrombus formation
(due to increased platelet activation)
LaPlace’s Law and Arterioles
Arterioles develop a smaller wall tension despite relatively high intravascular pressure
Thus, vasoconstriction of the arteriole involves less work, than of larger vessels.
With an aortic aneurysm, as the radius increases, ____
wall tension also increases
Pressure inside the aorta
100 mmHg
Radius inside the aorta
10-2 m
Tension inside the aorta =
1 (abstract unit)
Pressure inside the capillary
25 mmHg
Radius of the capillary
4 X 10-6 m
Tension in the capillary
1 X 10-4 (abstract units)
Venturi Effect
If liquid flows through a reduced area in a tube, the linear velocity of flow increases
Bernoulli Theorem
Pressure exerted by liquid upon the wall in a reduced area decreases
Compliance (capacitance) is related to ___
distensibility
Veins
Thin-walled vessels
Contain large volume of blood (2/3 of the circulating blood volume)
Venous pressure is very low (0-10 mmHg)
Venous valves provide unidirectional blood flow
Major Factors Affecting Vein Function
- Right atrial pressure (Central venous pressure)
- Respiratory pump
- Skeletal muscle pump (“Venous pump”)
- Venous valves
- Gravitational Effect Upon the Venous Pressure
Organization of Microcirculation
Artery .> Arteriole > Pre-capillaries > Capillaries > Post-capillaries > Venule > Vein
What are the three types of capillaries?
- Continuous capillaries
- Fenestrated capillaries
- Sinusoid capillaries
Typical capillary size is ___
5 mm
What is a continuous capillary?
What can pass through it?
One that has a basement membrane & endothelial layer
Interceullar cleft
Water and electrolytes can pass through
*TIGHT
What is a fenestrated capillary?
What can pass through it?
One that has fenestrations
Water, electrolytes and plasma proteins can pass through it
What is a sinusoid capillary?
What can pass through it?
One that has an incomplete basement membrane
Has intercellular gap
Water, electrolytes, plasma proteins and blood can pass through
*LEAKY
Where are continuous capillaries found in the body?
skin
muscle
lung
CNS
Where are fenestrated capillaries found in the body?
exocrine glands
renal glomeruli
intestinal mucosa
Starling Law in Microcirculation
- Capillary hydrostatic pressure (30 mmHg —–15 mmHg)
- Plasma oncotic pressure ( 25 mmHg )
- Interstitial fluid hydrostatic pressure ( -2 mmHg )
- Interstitial fluid oncotic pressure ( 8 mmHg )
Respiratory system is the link between ___.
the circulatory system and the atmosphere
High metabolic rate requires ____.
a specialized organ with high surface area gas exchange
Respiratory system has a very large ___
surface area for gas diffusion
The respiratory system provides close physical contact for ___
efficient gas exchange
The respiratory system provides excretory route for ____
volatile substances
The rspiratory system is important in ___
metabolism
What is the immunological role in the respiratory system?
airborne antigens
Nasopharyngeal Zone
NASAL CAVITIES, PARANASAL SINUSES, PHARYNX, and LARYNX
- air is cleaned
- air temperature and humidity may be changed
Tracheobronchial Zone
conducting zone: - 5 generations
respiratory zone: 17- 23 generations
mucocilliary transport (1cm/min)
respiratory bronchiole (0.5 mm diameter ) have no outer cartilage
Alveolar Zone
ALVEOLI
surface area 60-90 m2
300 million/adult lung
100-300 μm in diameter
0.1 µm -1 µm wall (alveolar-capillary membrane)
Factors Affecting Alveolar Stability
- Pulmonary Surfactant (which decreases surface tension)
- Alveolar Interdependence (If one starts to collapse the other will remain stable)
- Residual Volume (amount left at end of every breath- it’s what holds the alveoli open even during expiration)
Surfactant decreases ___
The ability of water molecules to interact with each other
Phospholipids reduce ___
surface tension of the alveoli
Alveolar Cells Type I
alveolar wall
Alveolar Cells Type II
produce surfactant
Pulmonary Surfactant Facts
Equalizes pressure within alveoli
Prevents collapse of bronchioles and alveoli
Without surfactant, small alveoli would collapse
Cartilage prevents upper airways from collapsing
Surfactant packed in lamellar bodies exported by exocytosis
Turbulence – mostly in the area of ______
branches and bifurcations
Laminar flow is found only ____
in the smallest airways
Turbulence has a significant effect in ____
airway resistance
There is the lowest pressure in which bronchiole?
the medium bronchiole
Mechanics of Breathing
- Lateral expansion of the thoracic cage
- Superior-inferior expansion of the thoracic cage
- Elastic recoil is responsible for lung elasticity
Pneumothorax
A dangerous pathophysiological condition. Pressure in the pleural cavity equals atmospheric pressure.
Negative Pressure in the Pleural Cavity
Intrapleural Pressure
- Negative pressure in the pleural cavity (-4 to -9 mmHg)
- Occurs during prenatal development
- Chest cavity grows more rapidly than the lungs
- Creates a semi-vacuum within the space
- Tends to pull lung towards chest wall à slightly expanded
Ventilation Work
Change in intrapleural pressure x Change in respiratory volume
Ventilation is the sum of:
- work against the elastic recoil of the lung tissue
- work against the resistance component of the airways
Slow inspirations and expiration
- resistance component is negligible
- elastic component accounts for the work
Rapid inspirations and expiration
- resistance component is more important
Dalton’s Law
PRESSURE IS PROPORTIONAL TO THE CONCENTRATION OF GAS MOLECULES
Henry’s Law
GAS DISSOLVES IN THE LIQUID IN PROPORTION TO PARTIAL PRESSURE AND SOLUBILITY
Arterial PO2 at sea level
O2 saturation
100 mmHg
96
Arterial PO2 at 5,000 feet
O2 saturation
80 mmHg
95
Arterial PO2 at 15,000ft
O2 saturation
50 mmHg
O2 Saturation: 85
Arterial PO2 at 30,000ft
O2 saturation
25 mmHg
Saturation: 50
What are lungs directly exposed to?
atmospheric pollutants
products of thermo-degradation
Process of lung injury seems to be ____.
rapid
A high concentration of nanoparticles = ____
rapid death