Exam 3 Flashcards
Cardiovascular Respiratory
Cardiac: Widowmaker
left anterior descending artery
– supplies left ventricle
Spontaneous depolarization of Heart
purkinje < bundle HIS < AV < SA
**SA to purkinje
Location of the Heart
Thoracic cavity: Mediastinum between lungs
- medial to lungs
- posterior to sternum
- anterior to ventral column
- superior to diaphragm
Location of the apex of the heart (distal end)
- distal end (apex) points to left (5th intercostal)
* hear heartbeat
Layers of the Heart wall
- Endocardium (inner)
- Myocardium: Muscle, middle tissue – hardest working muscle in the body
- Epicardium: Adipose
The pericardial cavity is located between what layers of the heart?
Parietal layer of serous peicardium) and cisceral layer of serous pericardium (Epicardium)
Pericardial effusion: fluids in heart muscle, heart wall = occurs in pericardial cavity
The Epicardium is also known as the _______ layer of the serous pericardium
visceral layer of the serous pericardium
The Pericardium (pericardial sac) is composed of two layers: fibrous and serous
What are the faetures?
- fibrous: sac w/tough CT
- serous: double layer
- parietal peri
- visceral peri (epicardium covers heart)
-serous fluid fills pericardial cavity
3 layers of the wall of the heart
- Epicardium (outside layer of CT)
- Myocardium (cardiac muscle)
- Endocardium (inner epithelial and CT lining heart and valves)
Chambers of the Heart
- Atria
- receive blood
* auricle (ext. chamber) - Ventricle
- expel blood
- separated by septum
* interatrial
* interventricular
Chambers of the Heart
- Atria
- receive blood
* auricle (ext. chamber) - Ventricle
- expel blood
- separated by septum
* interatrial
* interventricular
True/False: The heart valves are flaps that allow blood to flow in only one direction
True
Describe the Atrioventricular (AV) valves of the heart
- between atrium and ventricle
- blood from atrium to ventricle
- bicuspid (mitral; left))
- tricuspid (right side)
The semilunar valves of the heart separate the ventricles from the major heart arteries, allowing blood flow out of each ventricle.
List the semilunar valves
- pulmonary (RV and R pulmonary trunk)
2. aortic valve (LV and aorta)
The valve cusps are held in place by “heart strings” known as ______ which originate from papillary muscles (inside ventrical wall)
chordae tendinae
True/False: When a chamber wall contracts, blood is pumped through a valve. Backflow increases pressure on the cusps and closes the valves.
True
AV valves close during _____ contraction.
Ventricular contraction
To prevent backflow, papillary muscles contract (chordae tendinae) – keep valve cusps from prolapse
Blood returns to heart via
superior and inferior vena cava into right atrium
End diastolic area describes
final contraction of the atria to pump last bit of blood into ventricle
Oxygen exchange between blood and tissues occurs at the
capillaries
Describe cardiac circulation (coronary, pulmonary)
Vena cava – RA – RV – pulmonary artery – pulmonary vein – LA –LV – aorta – systemic
When does the heart feed itself?
Diastole
-coronary artery flaps are open
The right coronary artery gives rise to
right marginal artery and posterior descending artery
the left coronary artery gives rise to the
left circumflex and left anterior descending artery
The ______ vessels provide oxygenated blood to the heart
Coronary vessels
The left circuflex artery supplies blood to
lateral and posterior walls of the left ventricle
The PDA branches off of the left circuflex artery 10% of the time. These patients are considered to have ____-dominant circulation
Left
The left anterior descending artery supplies blood to
ant. wall of LV and anterior 2/5 of interventricular septum
The ______ gives rise to the posterior descending artery (PDA) in patients with right dominant circulation
right coronary artery (RCA)
The right marginal artery supplies the
RV
- papillary muscles
- posterior wall of heart
Pulmonary arteries carry ______
Pulmoanry veins carry
Arteries: deox blood to lungs
Veins: ox blood to LV of heart
______ refers to the series of contractions and relaxations of the heart to produce a complete heartbeat
Cardiac cycle
systole: vent. contraction
Diastole: vent. relax
During diastole, the atria and ventricles fill with blood. The atria contract to complete ventricular filling. During this time the ventricles are
relaxed
During systole the ventricles ______ forcing blood up and out of the heart arteries. The AV valves shut
Ventricles contract
- Av valves shut “lup”
- Semilunar valves shut”dup”
Conduction system of the heart
- SA “pacemaker” - wall of atrium
- AV node - septum at junction of RA and LA
- AV bundle of HIS - interventricular septum
- bundle branches (R and L)
- Purkinje fibers - myocardium wall
Spontaneous depolarization:
SA –AV–HIS–purkinje
Conduction velocity
time required for an electrical signal to spread through cardiac tissue
Speed: Purkinje fibers > SA > AV
Describe the Pacemaker action potential
Pacemaker: No phases 1 and 2
Phase 4: HCN “Funny current”
- -T-type Calcium channels
- -Inc. Na2+ influx
- -Dec. K+
Phase 0 (slope): L-type Ca2+ channels
Phase 3: Voltage-gated K+ channels
Describe depolarization of Heart
Phase 0 (upstroke): Na2+ influx
Phase 1: K+ efflux (out)
Phase 2: Plateau
- -Influx of Ca2+
- -L-type channels
Phase 3 (down-slope; rapid repolarization):
- Ca2+ channels close
- K+ channels (out)
Phase 4: Na, Ca2+ closed
–K+ open
EKG
- P wave: depol of atria
- QRS interval: depol of ventricles
- T wave: ventricular repol.
PR interval: Delay of AV
–ventricles fill
ST segment: ventricle repol starts
Describe the conducting zone of the lungs
- Conducting (airways)
- air in and out
- mucociliary escalatory
- SM lining
- Parasympathetic: Ach: Gq - bronchoconstriction
- Sympathetic: NE - bronchodilation
Describe the respiratory zone of the lungs
gas exchange
- alveoli
- elastic fibers and epithelial cells (type I, II)
- alveolar macrophages
Type I epithelial (pneumocytes)
squamous cells
- 95% of alveolar surface
- gas exvhange
Type II pneumocytes
- granular, cuboidal
- 5%
- surfactant (inc. compliance)
- replace type I
Conducting zone volume vs. Respiratory zone volume
Conducting: 150mL
Respiratory: 350mL
Emphysema is a desease of the
alveoli
Gas exchange begins at
respiratory bronchioles
Rhonci (low pitched wheezing) is an obstruction or secretion of the
largeer airways
*COPD, bronhiectasis, pneumonia, cystic fibrosis
Rales (crackles) are caused by the opening of the
small airways and alveoli (fluid)
*pulmonary edema, heart failure, pulmonary fibrosis or Resp. distress syndrome
Conducting zone are composed of
- cartilage (stops at trachea)
- goblet cells
- cilia (to resp. bronchioles)
- SM (to bronchioles)
*vocalization
Terminal bronchioles to alveoli are composed of
elastic fibers
no cartilage
Describe the epithelium in the conducting zone vs. respiratory zones
Conducting:
- pseudostratified ciliated columnar
- simple ciliated columnar
Respiratory:
3. respiratory epithelium (ciliated simple cuboidal)???
Dead Space is air that you breathe in, but does not participate in gas exchange. What are the two divisions?
- anatomic: nose to bronchioles
- no gas exchange
- “last air in, first air out” - Physiologic
- anatomic + functional
- air in resp. zone
- no gas exchange
Physiologic Dead Space
Taco Paco Peco Paco
Vd = VT PaCO2 - PeCO2/PaCO2
*If PeCO2 = 0 then no gas exchange
Preload is determined by
EDV
- EDV is proportional to right atrial pressure
- inc. RAP = inc. preload
Afterload is determined by what the ventricle is working against when ejecting blood. For the left ventricle, afterload is determined by
Aortic pressure
- higher aortic pressure = higher afterload
- RV = pulmonary artery
Stroke Volume is the volume of blood pumped out (LV) with every contraction (heartbeat)
*What are the factors affecting stroke volume?
Contractility
Preload
- inc. preload: inc. SV
- inc. contract: inc. SV
- dec. afterload: inc. SV
Calculate SV
SV = EDV - ESV
Cardiac output is the volume of blood pumped by the heart every minute.
Calculate CO
CO = SV x HR
CO = rate of O2 consump/arterial O2 - venous O2
Ejection fraction is a comparison of the volume of blood pumped out of the LV to the colume of the blood that remains in the LV after contraction
Calculate EF
EF = EDV -ESV/EDV
Stroke work is the work the heart performs on a single beat
Calculate stroke work
Stroke work = aortic pressure x stroke volume
Resistance is affected by
viscosity, length of blood vessel = direct proportion
radius = indirect proportion
*small radius: high resistance
Mean arterial pressure is a function of the hydrostatic forces exerted by the volume of blood in the circulation and the resistance within the vessel.
Calculate mean arterial pressure in the heart
MAP = CO x TPR
-
Pulse pressure
Systolic - diastolic
normal: 30-50
Blood flow describes the movement of blood over a given period of time
Calculate blood flow
Q = ΔP / R
Velocity:
V = Q/A
Compliance (of the heart) indicates the ability of the tissue to expand as the pressure rises
Calculate compliance
C = V/P
Elastance (of the heart) is the ability to recoil
Calculate elastance
E = P/V
Minute Ventilation is the amount of air breathed in per minute
VT x breaths/min
- 500
- Normal Respiratory rate: 12-20 bpm
ex: 500 x 12
Alveolar ventilation is the rate of air movement into and out of the lungs/minute
*corrects for dead space
(VT - VD) x breaths/min
ex; 500 -150 x 12 = 4200ml/min
What can be used to measure Residual volume?
Helium or Nitrogen
*can’t use spirometry
_______ is the volume inspired or expired with each normal breath. (at rest)
Tidal volume
500mL
______ is the volume that can be inspired over and above the tidal volume. Used during exercise.
Inspiratory reserve volume
*3000mL
_____ is the volume that can be expired after the expiration of a tidal volume.
Expiratory reserve volume
*1000mL
_______ is the volume that remains in the lungs after a maximal expiration. (cannot be measured by spirometry)
Residual volume
*1200mL
_____ the sum of tidal volume and IRV.
Inspiratory capacity
ICV: VT + IRV
_____ is the sum of ERV and RV. The volume remaining in the lungs after a tidal volume is expired. Includes the RV, so it cannot be measured by spirometry.
Functional residual capacity
FCR: ERV + RV
_____ is the max volume of air that can be expired after inspiration. It is the sum of tidal volume, IRV, and ERV.
Vital capacity
VC = VT + IRV + ERV
_____ is the sum of all four lung volumes. The volume in the lungs after a maximal inspiration.
*(includes RV, so it cannot be measured by spirometry).
Total Lung capacity
TLC = VT + ERV + IRV + RV
Obstructive vs. restrictive lung disease
Obstructive diseases: move flow volume loop to the left
- can’t fully exhale
- inc. RV
- inc. TLC
- dec. VT
ex: asthma, bronchitis, emphysema
Restrictive:
- move to right
- can’t fully inhale
- dec. TLC
- dec. RV
ex: fibrosis
FEV1/FVC ratio is acquired by performing the Forced expiration test: inhale as much as possible and rapidly exhale. What are the values for obstructive and restrictive lung diseases compared to normal?
FEV is forced expiratory volume in 1 sec.
Normal: 4/5 = 0.7 - 0.8
Restrictive: 3/3
Obstructive: 1/3
Obstruction (barrel chest): <70%
Restrictive: >70% or normal
Boyle’s law
volume of gase is inversely proportional to pressure
True/False: Pulmonary pressures are expressed relative to atmospheric pressure
True
Atmospheric pressure is the pressure of outside air. What is the normal atm?
760mmHg
At rest, the lung volume is equal to
FRC
Intralveolar pressure is within alveoli. At rest, the intralveolar pressure is equal to
atmospheric pressure
0
During inspiration
- diaphragm and external intercostals _____
- Alv p. ____ atm P.
- Lung vol = _____
- diaphragm and EIC’s contract
- Alv. pressure < atm. P.
- Lung volume = FRC + 1TV
Intrapleural pressure inside the pleural space is always ____ than intraalveolar pressure
Less than
*always negative during breathing
During expiration:
- diaphragm and external intercostals _____
- Alv p. ____ atm P.
- Lung vol = _____
- Diaphragm and EIC’s relax
- Thoracic space dec.
- Intrpleural pressure returns to normal
- Alv. P. > atm P
- lung vol. return to FRC
True/False: large sized alveoli have a less tendency to collapse
True
*surfactant dec. pressure and thus dec. tendency to collapse in small alveoli
Compliance (lungs) is a measure of distensibility. How is it calculated?
C = V/P
Compliance vs. Elastance
Distensibility vs. recoil
- Inc. elastance (dec. compliance)
- restrictive lung diseases (fibrosis)
- dec. surfactant - inc. compliance (dec. elastance)
- aging
- asthma
- obstructive (emphysema)
Hypoventilation vs. Hyperventilation
Hypoventilate:
- -retain CO2
- -dec. O2 (< 100mmHg)
Hyperventilate:
- -dec. CO2 (>40mmHg)
- -inc. O2 (>100mmHg)
Hb affinity for O2 is affected by:
- CO2
- Acidity (pH)
- DPG
- Exercise
- Temperature
Shift right: CADET (inc.)
Shift left: dec. all
The majority of CO2 is not bound to Hb, rather it is converted to HCO3 in RBC’s. Describe this process
- converted to H2CO3 via carbonic anhydrase
- H2CO3 breaks into H+ and HCO3-
- HCO3- exchange w/chloride shift into plasma
Chemoreceptors in the respiratory respond to chemical changes causing inc. breathing rate. List the types of receptors and the chemicals they respond to
Central:
- medulla
- dec. pH
- inc. CO2
Peripheral:
- carotid and aortic bodies
- dec.PO2
- inc. PCO2
- dec. pH
Resistance to blood flow equation
F = deltaP/R
- P = pressure
- Resistance
Which of the following provides oxygenated blood supply to the lungs?
- pulmonary arteries
- bronchial arteries
Bronchial arteries:
-supply bronchi and pleura
True/False: the pulmonary circulation has the capacity to accomodate two-fold to three-fold inc. in CO with little change in the pulmonary artery pressure
TRue
*ex: exercise
Fetal shunts: (R to L)
- Foramen ovale
- Ductus arteriosus
FO: R atrium to L atrijm
DA: shunt from pulmonary artery to aorta
*High pulm. pressure
True/False: In a standing position, gravity causes blood to naturally flow downward towards Zone 3
True
Zone 3: alveolar pressure less than venous pressure
high gas exchange
Sight of highest airway resistance in lungs
*turbulent flow
Conducting zone: Medium sized Bronchi
Normal V/Q ratio
Normal: 0.8
-exercise = 1
What happens when V/Q is infinite?
–Ventilation, no perfusion
*pulmonary embolism - obstructed pulmonary artery
**dead space problem
What happens when V/Q is zero?
–Perfusion, no ventilation
- shunt problem
- complete airway obstruction, ARDS
What happens when V/Q is low?
wasted perfusion
- low compliance
- fibrosis, bronchitis, asthma
What happens when V/Q is high?
some wasted ventilation
e.g. emphysema
Hypoxia is decreased O2 in the _____
Hypoxemia is decreased O2 to the
Hypoxia: tissues
-dec. organ perfusion
Hypoxemia: arteries
< 60mmHg
<90%
The following are potential causes of what disease?
- Ischemia
- Hypoxemia
- Decreased O2-carrying capacity of blood
Hypoxia
Ischemia:
- A clot
- V clot
- shock
Dec.O2
- anemia
- CO poisoning
- cyanide (ox phos)
- Methhemoglobineia
Why is hypoxia bad?
Decr. ATP
- reversible cell. injury and swelling (Na2+)
- irreversible injury and death (membrane damage; Ca2+)
- acidosis
Hypoxemia caused by
dec. PIO2
- hypoventilation
- high altitude
- diffusion
- V/Q defects
- R to L shunt
At a high altitude, what would you expect the A-a gradient to be?
normal
When you have low oxygen levels in the lungs, Hypoxic vasoconstriction occurs in the lungs. What does this cause?
Inc. resistance
- redirect blood flow from poorly ventilated alveoli, to good alveoli
- more perfusion to good areas
Aa gradient:
PAO2 - PaO2
What is the normal range?
PAO2 = partial pressure of O2 in the alveoli
PaO2 = partial pressure in arteries
5-15mmHg
Dec. PaO2 + Normal Aa gradient is caused by
extrapulmonary (hypoxemia)
hypoventilation - benzos, opiates or high altitude
Dec. PaO2 + Inc. Aa gradient is caused by
V/Q mismatch
R to L shunt
Diffusion impairments
Effect of 100% O2 on the A-a gradient on:
- High altitude
- Hypoventilation
- R to L shunt
- Altitude: normal
- Hypo: normal
- R to L: Inc; no improvement
- CO2, N2O and O2 (normal conditions) are all ____ limited gases
- CO and O2 (during exercise) are ____ limited gases
- perfusion
2. diffusion
Describe adaptations to dec. O2 availability at high altitude
Short term:
1. inc. respiration rate (hyperventilation)
*resp. alkalosis
- Inc. heart rate
- relieve perfusion limitation
Long term:
- HCO3- excretion
- -dec. pH - inc. EPO (RBC #)
- inc. carrying capacity - Inc. DPG
Response to smoking (lungs)
- squaous metaplasia
- goblet cell hypertophy, mucous hypersecretion
- chemotaxis (protease-anti-protease imbalance); inc. free radicals
- inactivate AAT and anti-oxidants
- inc. laryngeal cancer
Acidosis is characterized by too much acid in the body.
“not blowing off enough in lungs”
not excreting enough acid or inc. H+ ion formation
Alkalosis is characterized by less acidity
-lungs blow off too much
-excrete too much
diuresis, diarrhea
Metabolic acidosis
- high H+
- low HCO3-
- lungs: hyperventilate
- kidneys: excrete acids
Normal ranges
pH: 7.35-7.45
PCO2: 35-45
PO2: 95-100
HCO3-: 22-26
Metabolic alkalosis
*metabolic: H+ and HCO3- are opposite
- low H+
- high HCO3-
Lungs: hypO
kidneys: excrete HCO3-
Respiratory acidosis:
- high CO2
- High H+
- high HCO3-
–inc. renal HCO3- reabsorption
Respiratory alkalosis
-low CO2
-low H+
=low HCO3-
-dec. renal HCO3- reabsorption
Which of the following vessels would have the highest velocity?
a. aorta
b. arteries
c. capillaries
V = Q/A
- highest: aorta
- lowest: capillaries (exchange)
Ohm’s law describes that blood flow is determined by the pressure difference of a vessel and resistance.
Which of the following vessels has the higest resistance?
A. aorta
B. arteries
C. arterioles
D. capillaries
Q = P/R
Highest: Arterioles
Poiseulle’s law describes resistance to blood flow as being dependent on the arrangement of the blood vessesl (series vs. parallel)
What other factors affect flow?
R = 8nl/pi r2
n=viscosity
l=length
r=radius
Increase viscosity = inc. resistance
Increase length = increase resistance
Increase radius = dec. resistance
Reynold’s number describes flow of blood (laminar vs. turbulent). It is determined by the following equation:
N = pdv/n
p = density of blood d= diamter of vessel v = velocity of flow n = viscosity
If N < 2000 what kind of flow would we expect?
Laminar flow
> 2000 would be turbulent
NOTE: max velocity at center of vessel
Vascular compliance (capacitance) is determined by the equation: C = V/P
C= compliance V= volume P= pressure
Which vessels have the highest compliance? The lowest?
HIghest: veins
Lowest: aging arteries
How do you determine pulse pressure?
Systolic - Diastolic
*highest in large arteries
If a patient presents with arteriosclerosis, what happens to PP and systolic pressure?
inc. PP, inc. SyS, inc. MAP
If a patient presnts with aortic stenosis, the aorta cannot easily pump blood to the system. What happens to pulse pressure (PP), MAP, and systolic pressure?
all decrease
True/False: greater fraction of time is spend in diastole than in systole
True
How do you calculate mean arterial pressure?
MAP
Diastolic + 1/3 Pulse pressure
The dichrotic notch on a curve represents
aortic valve closing
Which phase of the SA node action potential sets the heart rate?
Phase 4
When the SA node is dysfunctional, a latent pacemaker can assume the job. What is the term for this?
ectopic pacemaker (AV, HIS, Purkinje)
Contraction of the SM of vessels requires which adrenergic receptor?
a1
M3
Heart function is under the control of which adrenergic recptor?
B1
rate, conduction velocity, contractility
(M2)
SK muscle vessels are under the control of which adrenergic receptor?
a1 - constrict
B2 - dilate
(M3)