Cardiac Physiology Exam 3

As inspired gas moves from the atmosphere through the airways into the alveoli the PO2 _________________________. This occurs because of the addition of _________________ & _________________ and because of Intrapulmonary shunting

Decreases, Water Vapor & CO2

Define PAO2

The partial pressure of O2 in alveolar gas

Calculate the PAO2 if the PB is 760 mmHg, the PaCO2 is 40 mmHg, the RER is 0.8 and the O2 percentage is 30% (FIO2 of 0.30).

169.9

How is the PaO2 determined?

PAO2= PIO2- PaCO2/0.8

Calculate the AaDO2 if the PaO2 is 90 mmHg

9.73mmHg

What is the normal value for the AaDO2?

up to 20 torr

The layers of the AC membrane from inside to outside are _______________________________, _______________________________, _____________________________ and _______________________________

surfactant, alveolar epithelium, interstitial space, and capillary endothelium

The AC membrane is ___________ thick.

1/2 micron

Fick's Law of diffusion measures ________________________________

amount of gas that transfers or diffuses across the tissues

CO2 diffuses _____________ faster than O2 because CO2's _______________ times more __________________

20x because CO2s 20 times more soluble

The diffusion constant is based on both _______________________ and _________________________. CO2 has such a high diffusion constant because of its ____________________________.

Henry and Grahams Law

Solubility

According to Fick's Law, if the thickness of the AC membrane increases, gas diffusion (V Gas) _____________________. If the Alveolar surface area decreases the gas diffusion ________________________.

decreases

decreases

Oxygen normally passes through the AC membrane in ________ seconds. Blood moves through a capillary in about _________ seconds. During exercise, the blood moves faster through the capillaries making the perfusion time (increase or decrease) _____________ to _________ seconds.

.25 (1/4)

.75 (3/4)

decreases

.75 to .25

If the AC membrane thickens (pulmonary fibrosis) diffusion time will (increase or decrease) ________________. This is referred to a ___________________ defect. This will (increase or decrease) the ___________________ in the pulmonary __________________ blood resulting in tissue hypoxia.

Is this a problem with CO2? ____________. Why or why not?

increase, diffusion, decrease, capillary

No its not a problem with CO2 because CO2 is 20x more diffusable and is not an issue until end stage diseases.

The Heart is located in the ___________________. It is rotated to the _______ and extends obliquely between the __________ & _________ intercostal spaces. It is a ______________ muscular organ that is __________ shaped and about the size of a human _____________.

center of the chest (mediastinum)

left

2nd and 5th

hallow

cone

fist

The base of the heart is _________ & ____________ and located at the ______

rib pointing toward the ________.

broad and flat

2nd

right shoulder

The apex of the heart is located at the ____________________________ space at the left mid-clavicular line, pointing towards the left hip.

5th intercostal

The heart beat is heard best at the ______________. This is referred to the PMI

which means __________________________.

apex

point of maximal intensity

What are the chambers of the heart?

right atrium, right ventricle, left atrium, left ventricle

The ________________________ divides the heart into left and right halves.

septum

There are ________ cardiac valves.

4

The Atrioventricular valves are located between the _________________ & __________________. They are named the

_____________ valve on the left and the _________________ valve on the right.

atrium and ventricles

mitral and tricuspid

The Semilunar valve on the left side of the heart is between the ___________ and _______________ . It is called the _____________________ Semilunar valve.

LV and aorta

aortic

The Semilunar valve on the right side of the heart is between the _______________ and ___________________ . It is called the _____________ Semilunar valve.

RV and pulmonary artery

pulmonic

What is the function of the Pericardium?

supports and anchors the heart to the chest wall

Identify the two layers of the Pericardium.

fibrous and serous

The Serous pericardium has two layers, what are they?

parietal and visceral

The fluid in the pericardial space prevents ________________________ between the 2 layers of the pericardium during systole and diastole. It is called

____________________ fluid.

friction

pericardial

The three layers of the heart are

endocardium, myocardium, epicardium

The middle layer of the heart is composed of cardiac

____________ tissue.

muscle

The outermost layer (epicardium) is AKA the ___________________ pericardium.

visceral

The function of the Pulmonary Vascular System is to bring the blood to the ____________ for gas exchange between the pulmonary capillaries and ____________ and then to return the blood to the left side (LA) of the heart

lungs

alveoli

The function of the Systemic Vascular System (AKA Peripheral Vascular System) is to bring blood carrying O2 & nutrients to the ____________________ where gas exchange occurs between _________________________ capillaries and the cells/tissues of the body.

body

systemic

Pulmonary components of the vascular system where the blood flows begin with the Right Atrium and end with the _______________

pulmonary veins

Systemic Components where the blood flows begin with the _____ ___________ and end with the superior and inferior vena cave.

left atrium

What is the path of blood through the vascular system

Deoxygenated blood flows from the vena cava into the right atrium, which then passes through the tricuspid valve into the right ventricle, from which it then passes through the pulmonary valve into the pulmonary artery, by which it travels to the lungs to be reoxygenated. One oxygenated, the blood travels from the lungs through the pulmonary veins into the left atrium, then the mitral valve, then the left ventricle, then the aortic valve, and finally the aorta, by which oxygenated blood is sent out to the rest of the body.

Both arteries and veins have _____ layers. The ___________ layer is thicker in

arteries than in veins, but pulmonary arteries are less muscular than in the systemic arteries. Arteries are known as ____________________ vessels

3

middle

distribution

Arterioles are known as _______________ vessels because they regulate and distribute the blood flow

resistance

Veins carry blood ____________ to the heart and are known as_______________ vessels.

back

capacitance

Capillaries are ________ layer thick and are the sites of _______________ & _____________ exchange. They are known as ________________ vessels.

1

gas and fluid

exchange vessels

The function of the lymphatic system is to remove excess ______________ &

_________________________ that leak out of the pulmonary capillaries and transport them back to the circulatory system via lymph ducts. The produce

________________________ and ____________________________. They act as ___________________ of particulate matter and bacteria.

proteins

fluids

lymphocytes and monocytes

filters

The PH determines the _________________________ or ____________________________ of the blood

acidity and alkalinity

The blood gas values in the pulmonary vascular system are the opposite of the ______________________ vascular system

systemic

Pulmonary arterial blood is ________________ and ____________________.

desaturated and acidic

Systemic arterial blood is _____________________________ and _____________________.

oxygenated and neutral

Identify the blood gas values in the pulmonary artery

pH _________, PCO2 ________ Torr, PO2 ________ Torr, SaO2 ________

In what other blood vessels are these blood gas values? _________

pH 7.37

PCO2 46 torr

PO2 40 torr

SaO2 75%

Systemic Veins

Identify the blood gas values in the aorta and systemic arteries.

pH_________, PCO2 _________ Torr, PO2 _________ Torr, SaO2 ________

pH 7.40

PCO2 40 torr

PO2 100 torr

SaO2 97%

A _________________ gradient is needed to make the blood flow. This gradient

is created by the pumping action of the ____________________. The greater the

gradient the ___________________ blood flow.

pressure

heart

greater

Pulmonary vascular resistance (PVR) is defined as the __________________ to

blood flow caused by the ________________ ________________ ____________

resistance

pulmonary blood vessels

Identify the formula for PVR: ________________________________. As the

Blood Pressure gradient increases, the PVR _____________________________.

If blood flow (Q) decreases the PVR _____________________________.

PVR= triangle P/Q

increases

increases

Normal PVR is lower than Systemic Vascular Resistance (SVR). What is the

normal amount for each? SVR __________________: PVR ________________

10x higher

15-20mmHg

<2mmHg

PVR is low but gets lower when Blood Pressure or blood flow increase because of two passive mechanisms. Name them _______________ & _______________

recruitment and distension

What are some factors that affect PVR in the extra-alveolar blood vessels (large pulmonary blood vessels)?

Increases it:

Decreases It:

Increase: Epinephrine, Dopamine and Vessel blockage/obstruction

Decrease: Oxygen, Increased blood flow and volume, and Nitric Oxide

How does Hypoxia or Hypercapnia (Increased PCO2) affect PVR? They

__________________________________ it

increase it

Increased PVR in the alveolar vessels (pulmonary capillaries) occurs mainly when alveolar pressure _______________________

increases

Identify four functions of the pulmonary vascular system.

____________________________, _________________________________,

____________________________, _________________________________

reservoir for blood

external respiration

fluid balance

thrombi filter

Ventilation is _______________ while respiration is ___________

Ventilation is the movement of air in and out of the lungs

Respiration is the exchange of gases (oxygen and carbon dioxide) across a membrane between the blood and the alveoli in the lungs

Differentiate between external and internal respiration

External: Gas exchange from the lungs into the blood

Internal: Gas exchange from the blood to the tissues

The Haldane effect describes

the binding of oxygen to hemoglobin in the lungs facilitates the release of carbon dioxide from hemoglobin

The Bohr effect describes

hemoglobin's lower affinity for oxygen secondary to increases in the partial pressure of carbon dioxide and/or decreased blood pH

How many ways is oxygen is transported in the blood?

__________. Identify each way O2 is transported in the blood.

________________________ & ___________________________

2

Dissolved into the Plasma (5%)

Bound to hemoglobin (95%)

What are the two structural components of Hemoglobin? ________

and ______________.

Iron structures (Fe+++) & a protein molecule - globin.

What is the normal amount of Hemoglobin in every 100mls of blood? ____________

12-16

Increased amount of Hgb. is known as __________________. Identify one clinical condition that would increase the amount of RBC's and Hb in the blood ______________.

Polycythemia

COPD

A decreased amount of Hb is known as ________________. Identify one clinical condition that causes a decrease in Hgb. _______________.

Anemia

Iron Deficiency

Identify four abnormal types of hemoglobin.

Fetal Hemoglobin, Methemoglobin, Carboxyhemoglobin, Sickle Cell Hemoglobin

Fetal Hemoglobin:

Hb F is chemically different than adulthemoglobin; has two Alpha polypeptide chains and twoGamma polypeptide chains; has greater affinity for O2.Gradually replaced over the first year of postnatal life

Methemoglobin:

Oxidation (loss of electrons) of the iron inthe Hb molecule changing the normal Ferrous state of theHb (Fe+++) to the Ferric state (Fe++); caused by ingestion ofchemical and drugs such as nitrates; in this state, Hb can'tcarry O2; blood has a brownish color (rusty).

Carboxyhemoglobin:

Carbon Monoxide (CO) has 210 timesthe affinity for hemoglobin compared to Oxygen; Hgb can'tcarry O2 when carrying CO; the blood is cherry red in color

Sickle cell hemoglobin:

Hb S has a different amino acidsubstituted into the Beta chain; causes RBC shape tochange from biconcave to a crescent or sickle shape;decreases Hgb's ability to carry O2 and RBC's have atendency to form thrombi causing pain

The Oxyhemoglobin dissociation curve shows the relationship between _______________ and __________________

between the partial pressure of oxygen and the percentage of oxygen bound to hemoglobin

As the PO2 increases, the SaO2 _____________________

increases

The P50 is the PO2 that saturates the Hemoglobin to _________. That PO2 is normally ________

50%

27 torr

If the curve shifts to the left it means _____________, _______________, ____________________ and _____________________

Higher Hgb O2 affinity

Lower PO2 to saturate Hgb to 50%

CaO2 increased

Lesser tissue oxygenation

Identify 4 factors that shift the curve to the left _________________, ________________, _________________, ___________________

Lower Hgb O2 affinity

HIgher PO2 to saturate Hgb to 50%

CaO2 decreased

Greater tissue oxygenation

When the curve shifts to the right it means _____________________, ________________, __________________, _____________________

Decreased pH Increase CO2

Increased Temperature

Increased 2,3 DPG

When the curve shifts to the left it means _____________________, ________________, __________________, _____________________

Increased pH Decrease CO2

Decreased Temperature

Decreased 2,3 DPG

Fetal Hemoglobin

Identify where in the blood Carbon dioxide is transported ______________________ and ____________________

Plasma and Red Blood Cells

Identify three ways carbon dioxide (CO2) is carried in the blood. _____________________, __________________ and

_________________

Dissolved in the plasma as a gas

Bound to hemoglobin as carbaminohemoglobin

As bicarbonate

How is most of the CO2 carried in the blood? ____________________

as bicarbonate

The chloride shift is important in __________ transport. Chloride shifts to maintain electrolyte balance after HCO3 (bicarbonate) moves into the plasma

carbon dioxide

If a patient has a hemoglobin level of 14g/dL and a PaO2 of 55mm Hg (85% saturation of Oxygen) approximately how much oxygen is transported to the peripheral tissues in each 100mL of blood?

16mL/dL

When the blood pH decreases the oxyhemoglobin dissociation curve shifts to the

Right and the P50 increases

If a patient normally has a 12g/dL Hb, cyanosis will likely appear when

7g/dL Hb is saturated with oxygen

The advantages of polycythemia begin to be offset by the increased blood viscosity when the hematocrit reaches about

55-60%

In healthy men the hematocrit is about

45%

Which of the following agents cause pulmonary vascular constriction

Epinephrine and Dopamine

Oxygen dilates

If the pressure in the pulmonary artery is 34mmHg and the pressure in the left atrium is 9mmHg what is the driving pressure?

25mmHg

The tricuspid valve lies between the

right atrium and right ventricle

The mean intraluminal pressure in the pulmonary capillaries is

10mmHg

Compared with the systemic circulation the pressure in the pulmonary circulation is about

1/10th of the pressure

The difference between the pressure in the lumen of a vessel and that of the pressure surrounding the vessel is called the

Transmural pressure

Which of the following causes pulmonary vasoconstriction

Hypercapnia

Hypoxia

Acidemia

Increased H+ concentration

Which of the following causes passive changes in the pulmonary vascular resistance

Transpulmonary pressure changes

Blood viscosity changes

What causes blood clotting at a traumatized site?

Thrombocytes (platelets)

Assuming a normal barometric pressure of 760, if the percentage of oxygen is 0.4 the partial pressure of oxygen would be

760x0.4

304mmHg

Which of the following gas laws states that in a mixture of gases the total pressure is equal to the sum of the partial pressures of each gas

Daltons

At sea level the normal percentage of carbon dioxide in the atmosphere is

0.03%

The normal transit time for blood through the alveolar capillary system is about

0.75 seconds

Under normal resting conditions the diffusion of oxygen and carbon dioxide is usually completed in about

0.25 seconds

1/3 of the time that is available