A&P1 Flashcards
Numbers, Formulas, Facts
What is the pressure of the left ventricle?
120-0 mmHg
What is the average pressure of the aorta?
100 mmHg
What’s the formula for MAP?
MAP = DBP + (1/3)(SBP-DBP)
What’s a normal CVP?
0 mmHg
What’s normal left atrial pressure?
~2 mmHg
What is normal PAP?
25/8
What is normal MPAP?
16 mmHg
What is ΔP for flow in the capillaries?
20 mmHg
What is capillary hydrostatic pressure (Pc)?
30 mmHg
What is interstitial fluid pressure (Pif)?
-3 mmHg
What is plasma colloid osmotic pressure (∏p)?
28
What is interstitial fluid colloid osmotic pressure (∏if)?
8 mmHg
PVR is ( / ) of SVR
1/7th
What is the X-sectional area of capillaries?
2500 cm2
What is the X-sectional area of the aorta?
2.5 cm2
The veins, venules, and venous sinuses contain what percentage of blood?
64% or 3200mL
Arteries contain what percentage of blood?
13%
Arterioles and capillaries contain what percentage of blood?
7%
What percentage of blood is in pulmonary circulation?
9%
What percentage of blood is in the heart?
7%
Systemic circulation contains what percentage of blood?
84%
Where do the lymphatic ducts empty?
Subclavian veins
Where is the isogravimetric point?
Level of the tricuspid valve. Also known as the phlebostatic axis.
Where is the isogravimetric point in relation to the foot?
1.5 meters above it
How much pressure does 1.5 meters add to the foot?
90 mmHg
What is the arterial pressure in the foot?
190 mmHg
Every ____ below the heart increases the pressure by ____.
1.36 cm; 1 mmHg
What’s the venous pressure at the isogravimetric point?
7 mmHg
What’s the equation for Reynold’s number?
What does Reynold’s number mean?
The higher the number the more likely you are to have turbulent flow.
What’s the formula for vascular compliance?
What’s the formula for vascular distensibility?
What does vascular distensibility tell us?
The higher the original volume the less distensible it is.
Ex: If the veins start out being full, they will not be able to increase volume as much as if they were not as full.
What is normal RAP?
0 mmHg
What are two things that arteriosclerosis causes?
- Increased pulse pressure
- Rigid and non-compliant arteries
Why would the kidneys decrease DBP?
To maintain MAP
What is the set point for the aortic arch receptors?
130-150 mmHg
What is the set point for the carotid baroreceptors?
100 mmHg
What low-pressure feedback system reflex increases HR by 10-15%?
Direct Atrial Stretch Reflex
What low-pressure feedback system reflex increases HR by 50-60%?
Bainbridge Reflex
What does ANP or ANF do?
Increases prostaglandin production in the kidneys, which leads to increases in renal blood flow and increased filtration (urine output increases).
What’s the pathway for the carotid high-pressure reflex?
Herring’s Nerve to the Glossopharyngeal nerve to vasomotor center in the brainstem
What’s the nerve pathway for the aortic arch reflex?
Sends info to the brain stem via the vagus nerve
How do stretch receptors work?
Stretching of the vessel increases Na+ permeability and increases the frequency of action potentials, which the brainstem then detects.
At what pressure does the aortic valve open?
80 mmHg diastolic
What’s the normal afterload pressure?
80 mmHg
The ability of the heart to change its SV independently of preload or afterload.
Contractility
What’s phase 4 of the pressure-volume loop?
Isovolumetric Relaxation
What’s phase 2 of the pressure-volume loop?
Isovolumetric Contraction
What’s phase 3 of the pressure-volume loop?
Period of Ejection
What’s phase 1 of the pressure-volume loop?
Period of Filling
What’s our normal ESV?
50 mL
What’s normal EDV?
120 mL
What’s normal SV?
70 mL
What is our highest CO at rest?
13 L/min
How high can CO get with sympathetic stimulation?
25 L/min
What are three things that can change SV?
- Preload
- Afterload
- Contractility
What does 1-2% of the population have?
Congenital Bicuspid Aortic Valve
Everyone over the age of 60 will have what?
Aortic Stenosis
What’s the formula for coronary perfusion pressure?
Coronary Perfusion Pressure =
Aortic Pressure - Wall Pressure
Concentric LV failure can be caused by what 2 things?
- Chronic HTN
- Aortic Stenosis
What type of dysfunction is concentric LV failure?
Diastolic dysfunction - filling problem
What four things can cause eccentric LV failure?
- MI
- Aortic/Mitral Regurgitation
- VSD
- Congenital Dilated CM
What type of dysfunction is eccentric LV failure?
Systolic Dysfunction
Sarcomeres are added end to end “in series”
Eccentric
sarcomeres are added side by side
Concentric
What is the normal coronary blood flow?
225 mL/min or 70 mL /100g of heart muscle
What two arteries does the LCA split into?
- LAD
- Left Circumflex
What branches off of the left circumflex in 15% of people?
Posterior Descending Artery (PDA)
What branches from the RCA in 85% of people?
Posterior Descending Artery (PDA)
What would the normal resting HR be if parasympathetic stimulation was removed?
110
What controls motor innervation for the diaphragm?
Phrenic Nerves
What are the 2 layers of the serous pericardium?
- Parietal - outer layer attached to the fibrous pericardium
- Visceral - inner layer attached to the heart
What is causing the 3rd heart sound?
Rattling of the Right Fibrous Anulus
At what part of the cardiac cycle is the 3rd heart sound heard?
At the beginning 2nd 1/3 of diastole or 2/3 into diastole
When is the 4th heart sound heard?
At the beginning of the last 1/3 of diastole or the 3rd part of diastole.
What is the normal hearing wavelength for humans?
20 Hz - 20 kHz
What is the loudest heart murmur?
Aortic Stenosis
How long does 2nd heart sound last for?
0.11 s
How long does the 1st heart sound last for?
0.14 s
What makes the 1st heart sound?
Closure of the AV valves
What makes the second heart sound?
Closure of the Aortic and Pulmonic (Semi-Lunar) valves
When is most of the volume ejected from the LV?
During the 1st 1/3 of Ejection
At what point during diastole is most of the ventricle filled?
The 1st 1/3rd of filling
a wave
Contraction of the atria
X Descent
relaxation of the atria
c wave
AV valve bulge backward, isovolumetric contraction
Atrial Pressures increase during systole as the atria fill
v wave
h plateau
diastasis, occurs during filling
Occurs just before the a wave
During rapid filling of the ventricle in the 1st 1/3 of diastole
y descent
What’s the order of the CVP waveform?
a
c
x
v
y
h
2 seconds, followed by 2 seconds, followed by 2 seconds
inspiration, expiration, and then nothing
What is our thoracic pressure at the end of expiration?
~ -4 mmHg
What is our thoracic pressure during inspiration?
~ -6 mmHg
What’s the venous return or resistance to venous return equation?
At what pressure will the aortic valve close?
100 mmHg
When does systole end on an ECG?
When the T-wave ends
When do the ventricles contract on an ECG?
R-wave
What is normal arterial oxygen content? Units?
20 mL/dL
What is normal oxygen consumption? Units?
250 mL/min
What is normal arteriovenous oxygen difference? Units?
5 mL/dL
What is normal mixed venous O2 saturation?
75%
Where do we auscultate the mitral valve?
5th intercostal space, midclavicular line
Where do we auscultate the tricuspid valve?
5th intercostal space, left sternal border
What two things dampen the a-line waveform?
- Clot in the a-line
- Air in the a-line
Where does the superior thyroid artery branch off?
External Carotid
Where does the inferior thyroid artery branch from?
Subclavian Arteries
How many arteries supply the thyroid?
4
How many parathyroid glands are there?
4
How long does thyroid hormone get stored for?
2-3 months
What is the blood flow per minute in the thyroid gland?
5x its mass
What nerves branch from the vagus nerves?
Recurrent Laryngeal nerves
Which recurrent laryngeal nerve wraps around the back of the brachiocephalic artery and then ascends to the larynx?
The right recurrent laryngeal nerve
Which recurrent laryngeal nerve wraps around the front of the aortic arch and then ascends to the larynx?
The left recurrent laryngeal nerve
What controls the skeletal muscles in the voicebox?
Recurrent laryngeal nerves
Where is the thyroid gland located?
Under the base of the thyroid cartilage
What’s inside of the thyroid cartilage?
Larynx “Voice Box”
What is the exchange rate for the Na+ / I- pump? What type of transport is it?
2:1. 2 Na+ and 1 I- enter into the cuboidal epithelial cells via cotransport
What’s the exchange rate for I- and Cl-? Where are they transported?
1:1 exchange. Iodine gets pushed out into the colloid space and Cl- comes in from the colloid space.
Who oxidizes iodine?
H2O2. Removes negative charge using oxidation.
What is TRH? Where does is it come from? Where does it go?
Thyrotropin Releasing Hormone (TRH); Released from hypothalamus and goes to pituitary gland.
What is TSH? Who releases it?
Thyroid Stimulating Hormone (TSH); Released by the anterior pituitary in response to TRH.
Where does TSH bind? What does it cause?
Binds on receptors on the thyroid gland “cuboidal epithelial cells”; Causes proteases and lysosomes to breakdown thyroglobulin to release T3 and T4.
What are the three carrier proteins for TH?
- Thyroxine-binding globulin (TBG)
- Pre-Albumin
- Albumin
Which form of TH is more free circulating in the plasma? Why?
T3; because T4 is more lipophilic and more likely to be bound to a carrier protein.
What is PTU? What does it do?
Propylthiouracil; Inhibits thyroid peroxidase
What causes exophthalmos in Grave’s disease?
Inflammation from the thyroid antibodies.
What type of shock can you recover from without intervention?
Non-progressive or compensatory
What type of shock requires intervention to survive?
Progressive
Which type of shock will you not survive from even with intervention?
Irreversible/Uncompensated or “Decompensated” shock
What is myocardial depressant factor? Where does it come from? What does it do?
Endotoxin; From Gram ( - ) bacteria in the gut; Decreases CO
How much of our blood volume can we lose and still autoregulate our BP?
20% = 1 L of blood
Name 3 things that can inhibit the body’s autoregulation reflexes.
- Anesthesia
- ACEi
- B-Blockers
What is a normal cardiac reserve?
400% or an increase to 25 L/min
SBP drops by how much with inspiration?
10 mmHg
What is dextran? What does it do?
Large sugar molecule; it increases colloid oncotic pressure
At what MAP is death certain if there is no intervention?
45 mmHg
Iodide
I- ; reduced form of Iodine that is normally found in nature.
What is normal BSA?
1.7 m2
What are the 3 causes of mitral stenosis?
- Autoimmune reactions
- Rheumatic fever
- Strep
What are 6 causes of aortic stenosis?
- Poor diet/HLD
- Diabetes
- Autoimmune/Rheumatic Fever
- Age
- Infection
- Congenital
What percentage of adenosine can the heart restore in 30 minutes?
2%
What is the function of endogenous adenosine?
Vasodilation
What are the 3 cusps of the aortic valve?
- Posterior
- Right
- Left
What are the 3 cusps of the pulmonic valve?
- Anterior
- Right
- Left
What are the cusps of the Tricuspid valve?
- Anterior
- Posterior
- Septal
What are the cusps of the Bicuspid/Mitral valve?
- Anterior
- Posterior
- Commissural*
Not a true cusp. Extension of posterior cusp.
What are the cartilaginous rings of the posterior R and L sides of the heart?
Left & Right Fibrous anulus
The opening for the bundle of His shares borders with which 4 cartilaginous rings?
- Right fibrous trigone
- Left fibrous anulus
- Right fibrous anulus
- Fibrous ring of aortic valve
The tendon of conus links what two cartilaginous rings together?
- Fibrous ring of pulmonary valve
- Fibrous ring of aortic valve
The left fibrous trigone and the right fibrous trigone cartilaginous rings link which two structures together?
Left heart and aorta
V wave
An increase in atrial pressure during systole as the atria fill
What phase of the cardiac cycle is the a wave?
end diastole
What phase of the cardiac cycle is the c wave?
early systole
What phase of the cardiac cycle is the v wave?
Late systole
What phase of the cardiac cycle is the h wave?
mid to late diastole (diastasis)
What phase of the cardiac cycle is the x-descent
Mid systole
What phase of the cardiac cycle is y-descent?
Early diastole
What is a normal PAWP?
10 mmHg
What is SVR in PRU? What are the units?
1 mmHg/mL/sec
What is CGS
Centimeters x Grams X Seconds
What is 1 CGS equal to?
1 dyne x second / cm5 or mmHg/L/min
How do you convert PRU to CGS?
PRU x 1333
What is iodinase? What does it do?
Breaks off one iodone atom to take T4 to T3
What is the THR? Where is the THR?
Thyroid Hormone Receptor (THR) and it is inside the nucleus.
Where does the THR complex bind??
Retinoid-X Receptor
What does a high dose of Iodine do?
Treats hyperthyroidism by overwhelming peroxidase
What are the 4 treatments for hyperthyroidism?
- I-131
- PTU
- High Dose Iodine
- Surgery
What can cause hyperthyroidism?
- Grave’s Disease
- Trauma
- Surgery
- Too much I in diet
What can cause hypothyroidism?
- I deficiency
- Hashimoto’s
- Dysfunction of hypothalamus
- Hypophysectomy
How do we prevent the uptake of other more poisonous forms of iodine in a nuclear war?
Take regular iodine.
Which type of vessel has the largest wall thickness to internal diameter ratio?
Arterioles
Who supplies most of the SVR?
Arterioles
What is the pressure in the sagittal sinus?
~ -10 mmHg
How long would it take you to pass out if you didn’t contract your leg muscles while standing?
5 minutes
In which coronary artery will you see retrograde flow and when?
LCA during early systole
What is the AP firing equation?
ΔI / ΔP = maximum
What percentage of O2 is taken by the coronary arteries? The tissues?
75%; 25%
1dL of arterial blood contains how many mL of O2?
20mL of O2
75% of people with a bicuspid aortic valve will what type of cusp merge?
Left and Right
25% of people with a bicuspid aortic valve will have what type of cusp merge?
Posterior and Right
Where does the right recurrent laryngeal nerve go?
RRLN wraps around the back of the brachiocephalic artery and then ascends to the larynx.
What medication mimics sympathetic nervous system in the blood vessels to increase filling pressures?
Phenylephrine
What phase of the volume-loop cycle for aortic regurgitation has the most backward flow?
Phase I
What phase of the volume-loop cycle for mitral regurgitation has the most backward flow?
Phase III
What’s the formula for EF?
EF = SV / EDV x 100%
What is PTH? Wheredoes it come from? What does it do?
Parathyroid hormone; Parathyroid gland; Regulates Ca2+
What is the highest amount of TH in the body?
T4
What are the starting blocks of TH?
Tyrosine and Iodine
What causes Beri Beri? How?
Thiamine (Vitamin B1) deficiency; Renders part of the ETC ineffective
What happens in MIs lasting 30 minutes or more?
No substrate to build ATP off of because it’s all been used up and adenosine has leaked out.
The atrial stretch reflex also causes a reflex in the kidney that does what?
Inhibits renal sympathetic nerve activity.
Angiotensin II and aldosterone production can be inhibited by what endogenous substance?
ANPeptide or ANFactor
What are 4 things that can shift the cardiac output curve to the right?
- Positive pressure ventilation
- Blowing a trumpet
- Surgically opening the chest
- Cardiac tamponade
What are 2 things that can shift the cardiac output curve to the left?
- Breathing against a negative pressure (breathing through a straw)
- Removing a patient from a positive pressure ventilator
What doesn’t shift the cardiac output curve?
Psf
Blowing murmurs of relatively high pitch are associated with
Valvular insufficiency/regurgitation
What’s the most important factor for the progression towards irreversible/progressive/uncompensated shock?
Cardiac Function
What are two things that can inhibit the secretion of TRH?
High level of TH or TSH
What three thyroid disorders will we possibly see Exopthalamos?
Hashimoto’s
Hyperthyroidism
Graves
What organs can we shift blood/fluid from?
- Spleen
- GI system
- Pulmonary system
- Liver
What is the formula for cardiac reserve?
(Max CO - Resting CO) / Resting CO = % Cardiac Reserve
What is essential for preventing coronary steal?
Bedrest
What are two anatomical reasons in the failing heart that can cause arrhythmias?
- Longer AP pathway due to stretching of the heart muscle
- Scar tissue build-up that does not conduct electrical activity
What is the normal total body water amount in a 70kg adult? How much are in the ICF and ECF respectively?
42 L; 28L ICF and 14L ECF.
BONUS: 3L Plasma Volume (out of the ECF)
What type of shock is caused by anesthesia? How does it cause it?
Neurogenic; decreases Psf
What type of shock can develop from the other types of shock? Why?
Septic Shock due to lack of blood flow and ischemia to the intestines.
What does digoxin do?
produces an increase in blood flow and vasodilation a decrease in SVR, CVP, and HR. The vasodilation is the result of an increase in CO and direct baroreflex-mediated withdrawal of sympathetic vasoconstriction.
What’s an example of a medication we use to override the kidney?
Diuretics or ACEi
What causes the plateau at 50% of our normal CO or MAP?
CNS ischemic response or reflex
During the CNS ischemic response what would you see on the arterial pressure wave?
Oscillations from the Baro-Rs
If our BP drops more than 10 points during inspiration, what could that mean?
Hypovolemia
What are two medication types that can decrease capillary permeability?
Steroids and Pressors
How much blood in mL is in the heart and lungs?
350 mL; 450 mL
What makes TBG? What is TBG?
Liver; Thyroid Binding Globulinis a protein that binds T3 and T4
What percentage of T3 and T4 are released from the thyroid?
7%; 93%
What’s the difference between Hashimoto’s and Grave’s?
Graves’ disease is caused by thyroid-stimulating antibodies to the TSH receptor (TSHR), whereas Hashimoto’s thyroiditis is associated with thyroid peroxidase and thyroglobulin antibodies.
