Lecture Exam 3 Flashcards
Define arteries
LARGE, branching vessels that take blood AWAY from the heart
Define arterioles
SMALL, branching vessels with HIGH resistance
How can arterioles control blood pressure?
by changing their diameter, thus resistance
Define capillaries
the site of exchange between blood & tissue
Define venules
small converging vessels
Where do WBCs exit?
venules
Define veins
large converging vessels that take blood TO the heart
Where is 2/3 of the blood held?
within the veins
Where does gas exchange occur, thus causing the blood to become deoxygenated?
capillaries
What are erythrocytes?
RBCs
What are leukocytes?
WBCs
What transports oxygen & carbon dioxide?
RBCs (erythrocytes)
What defends the body against pathogens?
WBCs (leukocytes)
What are important in blood clotting?
platelets
What is serum?
plasma without proteins
What is the most important protein in plasma?
albumin
What is blood flow driven by?
blood pressure
moves from high to low pressure
Where is there SERIES flow?
within the cardiovascular system
Where is there PARALLEL flow?
within one specific circuit
How does O2 get into the blood?
through the pulmonary circuit (in capillaries)
O2 diffuses from alveoli into the blood
What side of the heart carries OXYGENATED blood?
left
What side of the heart carries DEOXYGENATED blood?
right
What causes valves to open?
pressure change
What do valves do?
prevent back flow of blood
What do AV valves have that semilunar valves don’t?
chorde tendineae
What cells provide the rhythm to heartbeat?
pacemaker cells
What conduct the action potentials initiated by pacemaker cells?
conduction fibers
Which node is the pacemaker of the heart?
SA node
Which node has a FAST firing rate?
sinoatrial (SA) node
Which node has a SLOW firing rate?
atrioventricular (AV) node
Where is the sinoatrial (SA) node found?
in the RIGHT atrium
Where is the atrioventricular (AV) node found?
between the ventricle & atrium
A gap junction is used for what?
electrical coupling
What makes up intercalated disks?
desmosomes
Intercalated disks are used for what?
resisting mechanical stress
What causes the slow firing rate of the AV node?
AV nodal delay
Do the ventricles or the atria contract first?
atria
Removal of what from the cytosol allows cardiac muscle to relax?
calcium
A slowed conduction through the AV node would result in what?
2nd degree heart block
A loss of conduction through the AV nodes would result in what?
3rd degree heart block
When atrial & ventricular contractions become independent, what kind of heart block is that?
3rd degree heart block
Extra systole is caused by what?
a premature atrial contraction (PAC)
Define systole
ventricular CONTRACTION
Define diastole
ventricular RELAXATION
When do AV valves open?
when ATRIAL pressure is GREATER than ventricular pressure
When do semilunar valves open?
when VENTRICULAR pressure is GREATER than arterial pressure
What phase of the cardiac cycle does aortic pressure change?
phase 3 (ventricular ejection)
During what phases of the cardiac cycle is ventricular volume CONSTANT?
phase 2 (ventricular contraction)
phase 4 (ventricular relaxation)
What causes the dicrotic notch during aortic diastole?
back flow of blood causing an increase in pressure
During aortic diastole how do the aortic valves behave?
they are closed
During aortic systole how do the aortic valves behave?
they are open
What is the lowest pressure?
diastolic pressure
What is the highest pressure?
systolic pressure
Define EDV
end diastolic volume
the volume of blood in the ventricle at the end of diastole
Define ESV
end systolic volume
the volume of blood in the ventricle at the end of systole
How can you calculate stroke volume?
EDV - ESV
Define SV
stroke volume
the volume of blood ejected from the ventricle with each beat
Define EF
ejection fraction
fraction of EDV ejected during a heart beat
How do you calculate ejection fraction (EF)?
SV / EDV
found as a percent!
What does ejection fraction (EF) reflect?
cardiac function
What is the normal range for ejection fraction (EF)?
50% - 70%
What causes the first (soft) thump of the heart beat?
AV valves closing
What causes the second (loud) thump of the heart beat?
semilunar valves closing
What phases of the cardiac cycle can you hear heart beats?
phases 2 & 4
Define CO
cardiac output
the volume of blood pumped from the heart per MINUTE
How do you calculate CO (cardiac output)?
SV x HR
measured in L/min
or mean arterial pressure/total resistance
How can you control cardiac output?
regulate HR and SV
How can the sympathetic nervous system affect CO?
- increase sympathetic activity
- epi binds to B1 receptors in SA node
- increase opening of Ca2+ & Na+ channels
- increase rate of depolarization
- increase HR & CO
How can the parasympathetic nervous system affect CO?
- increase parasympathetic activity
- norepi or acetylcholine bind to muscarinic receptors in SA node
- open K+ channels & close Ca2+ channels
- decrease rate of depolarization
- decrease HR & CO
What hormones can increase CO?
epinephrine & glucagon increase HR & CO
What primary factors affect SV?
- ventricular contractility
- EDV (preload)
- afterload (increasing this decreases SV)
What factors affect EDV (preload)?
- filling time
- atrial pressure
- venous pressure
What factors affect afterload?
- blood pressure in aorta during ejection
- aortic valvlar stenosis
What does increasing afterload cause on SV?
increasing afterload, increases resistance, DECREASES stroke volume
The circulatory system is what kind of system?
a closed system
What is the typical mean arterial pressure (MAP)?
93 mm Hg
What is the typical mean central venous pressure (CVP)?
0 mm Hg
Which circuit, systematic or pulmonary, has the greatest resistance?
systematic
What is the biggest effector of resistance?
RADIUS
Define vasoconstriction
decreased radius
thus increased resistance
Define vasodilation
increased radius
thus decreased resistance
In the vessel wall, what do endothelial cells do?
line inner layer of blood vessels
In the vessel wall, what does smooth muscle do?
contract or relax to change blood flow
In the vessel wall, what does connective tissue do?
line the outside of blood vessels
What determines systolic pressure?
elastic arteries
What determine diastolic pressure & tissue perfusion?
arterioles
What are the properties of elastic arteries?
high elasticity
low compliance
How do you calculate compliance?
change in volume / change in pressure
The heart is what kind of pump?
discontinuous pump
The role of elastic artery is what?
hydraulic filter
expand as blood enters then recoils during diastole
Define compliance
how well something can stretch
Define elasticity
how well something can recoil after being stretched
How are compliance & elasticity related?
inversely
What can affect pulse pressure?
SV and compliance
Which arm is the best to use when measuring blood pressure?
left arm
What is the first sound, during compression, that you hear when manually taking blood pressure?
systolic pressure
What is the second sound, after release, that you hear when manually taking blood pressure?
diastolic pressure
What serve for regional blood flow?
arterioles
High metabolic activity (large amounts of metabolic byproducts) causes what?
vasodilation
What are the metabolic factors?
CO2
K+
H2
organic acids
Define active hyperemia
increases blood flow in response to increased metabolic activity
Define reactive hyperemia
increased blood flow in response to a pervious reduction in blood flow
(blockage then blockage released)
What does an increase in transmural pressure cause in blood vessels?
vasoconstriction
Stretch of a vessel induces what?
contraction
What happens to blood vessels during exercise?
vasodilation
In order to cause vasoconstriction in smooth muscle, what does norepi bind to?
alpha adrenergic receptors
What happens to blood vessels when alpha adrenergic receptors get bound to?
vasoconstriction
What happens to blood vessels when beta 2 receptors get bound to?
vasodilation
What releases epinephrine?
adrenal medulla
What releases vasopressin?
posterior pituitary
What does vasopressin cause?
vasoconstriction
What does angiotensin II cause?
vasoconstriction
Define continuous capillaries
SMALL gaps between endothelial cells
Define fenestrated capillaries
LARGE gaps between endothelial cells that form fenestrations
Define discontinuous capillaries
FULL gaps between the basal membranes of endothelial cells
What kind of capillary is most common?
continuous
How do gasses & lipophilic molecules move across capillaries?
free diffusion
How do small lipophobic solutes move across capillaries?
pass through cleft or cell-cell junction
How do large lipophobic solutes move across capillaries?
transcytosis (bound to transport vesicles)
What pressures pull H2O in (absorption)?
capillary osmotic & interstitial fluid hydrostatic pressures
What pressures force H2O out (filtration)?
capillary hydrostatic & interstitial fluid osmotic pressures
Define hydrostatic pressure
the pressure of fluid exerted against capillary wall
Where does filtration occur?
arterioles, capillary, & venuoles
When does absorption occur?
immediately after a hemorrhage or arteriolar constriction in capillaries
What do venules do?
connect capillaries to veins
Veins function as a blood reservoir, which means…?
they expand with little pressure change
Do veins or arteries have higher compliance?
veins
arteries have higher elasticity
When skeletal muscles contract, what happens to veins?
veins get squeezed which increases their pressure & sends blood towards the heart
How does inspiration affect venous pressure & return?
decreases pressure in thoracic cavity
increases pressure in abdominal cavity
increases venous pressure
increase venous return
How does increasing venomotor tone (through sympathetic stimulation) affect venous compliance, pressure, & return?
increasing venomotor tone, decreases compliance, increases pressure & return
What is the main function of the lymphatic system?
to collect & return things to circulation
act as a defense system against foreign bodies
What are the determinants of mean arterial pressure (MAP)?
HR, SV, resistance
Define HYPOtension
inadequate blood flow
Define HYPERtension
too much blood flow
is a stressor for heart & blood vessels
During hypotension, how does MAP compare to normal?
it is LESS than normal
During hypertension, how does MAP compare to normal?
it is MORE than normal
Long-term regulation of MAP regulates what?
blood volume
Short-term regulation of MAP regulates what?
CO & resistance
Define external respiration
exchange of O2 & CO2 between the atmosphere & body tissues
Define internal respiration
use of O2 in mitochondria to produce CO2
What zone is there no gas exchange?
conducting zone
What is the purpose of the conducting zone?
functions as a “dead space”
purpose is to deliver air
What zone is there gas exchange?
respiratory zone
What are the structures of the thoracic cavity?
lungs, chest wall, intrapleural space
What are the bones in the chest wall?
rib cage, sternum, thoracic vertebrae
What are the respiratory muscles in the chest wall?
internal & external intercostals, diaphragm
Elastic forces of the lungs & chest wall work to do what?
EXPAND the chest wall & collapse the lung
At the end of exhalation, what is the intrapleural space pressure?
-4 mm Hg
During a pneumothorax, what is the intrapleural pressure?
0 mm Hg
At the end of exhalation, what is the atmospheric pressure?
0 mm Hg
At the end of exhalation, what is the intra-alveolar pressure?
0 mm Hg
At the end of exhalation, what is the transpulmonary pressure?
4 mm Hg
How do alveolar pressure & atmospheric pressure compare during inspiration?
atmospheric pressure is GREATER than alveolar pressure
How do alveolar pressure & atmospheric pressure compare during expiration?
atmospheric pressure is LESS than alveolar pressure
What alters the driving force of airflow?
changes in alveolar pressure
Greater surface tension in alveoli creates higher resistance to what?
alveolar expansion
What 2 factors affect surface tension?
surfactant & alveolar size
Smaller alveoli have more of what compared to larger alveoli?
more surface tension, thus more surfactant to decrease the surface tension & even out the pressure
Why is total resistance in small airways lower?
because they run in parallel
Which airway generations have higher resistance?
first 8 generations, larger airways
How does FEV1 / FVC look for obstructive diseases?
lower FEV1 / FVC due to restricted expiration
below 80%
How does FEV1 / FVC look for restrictive diseases?
same or increased as FEV1 can be normal but FVC is DECREASED
above 80%
Example of obstructive disease
COPD or asthma
Example of restrictive disease
fibrosis
What is the normal FEV1 / FVC?
80%
What is minute volume?
the total amount of air that flows in & out within a minute
How do you calculate minute volume (MV)?
tidal volume (TV) x breaths per min
Define alveolar ventilation
the amount of fresh air that enters the alveoli each minute
OR
volume of air reaching gas exchange areas per minute
How do you calculate alveolar ventilation (Va)?
breaths per min x (TV - dead space volume)
How do you calculate partial pressure of a gas?
% gas x sum of total gases in mixture
Which gas is more soluble in water than O2?
CO2
What are the 2 places gas exchange occurs?
lungs & capillaries (terminally tissues)
As the length of the capillary increases, what increases & what decreases?
PO2 increases
PCO2 decreases
Which way does O2 diffuse?
from blood to cells
Which way does CO2 diffuse?
from cells to blood
What is gas diffusion rate determined by?
surface area
pressure gradient
membrane thickness (inversely related)
PO2 in arterial blood
100 mm Hg
PCO2 in arterial blood
40 mm Hg
What relationship determines alveolar PO2 & PCO2?
rate of alveolar ventilation relative to the rate of O2 use & CO2 production
Define hyperpnea
an increase in ventilation to meet an increase of metabolic demands
(body is using more O2, producing more CO2, increase ventilation, increase blood flow to accommodate)
Define dyspnea
labored/ difficulty breathing
Define apnea
temporary stop of breathing
Define tachypnea
rapid, shallow breathing
Define hypoxia
low O2 to the tissues
Define hypoxemia
low O2 in the BLOOD
Define hypercapnia
too much CO2 in the blood
Define hypocapnia
low CO2 in the blood
Define hyperventilation
ventilation exceeds CO2 production
arterial PO2 increases
arterial PCO2 decreases
Define hypoventilation
CO2 production exceeds ventilation
arterial PO2 decreases
arterial PCO2 increases
How is the majority of O2 transported by blood?
bound to Hb (hemoglobin)
The amount of O2 dissolved in plasma is determined by what?
alveolar PO2
Define oxyhemoglobin
O2 bound to all sites of Hb
Define deoxyhemoglobin
O2 is not bound to all sites of Hb
Define carbaminohemoglobin
CO2 bound to Hb
Define carboxyhemoglobin
CO bound to Hb
How many O2 binding sites does Hb have?
4
Define capacity
the max amount something can hold
dependent on Hb concentration
Define content
the actual amount something is holding
How do you calculate blood oxygen content?
capacity x % (as a decimal) filled
When completely saturated, how much O2 does 1g of Hb carry?
1.34 ml O2
Normal blood Hb levels
12-16 g/dL
In arterial blood, how saturated is Hb?
above 95%
In venous blood, how saturated is Hb?
75%
How is the affinity of Hb for O2 affected?
by temp, pH, PCO2
What (other than increasing temp, PCO2 & decreasing pH) can lower O2 to Hb binding affinity?
presence of 2,3-DPG & CO
How is the majority of CO2 transported in the blood?
through plasma bicarbonate
What are the 2 respiratory control centers?
medulla & pons
What part of the medulla controls expiration?
VRG (ventral respiratory group)
What part of the medulla controls inspiration?
DRG (dorsal respiratory group)
What in the pons regulates the medulla?
PRG (pontine respiratory group)
What controls the firing pattern & frequency of the neurons of the VRG & DRG?
central pattern generator (CPG)
What do peripheral chemoreceptors do?
respond directly & indirectly to PCO2 & PO2 changes
What do central chemoreceptors do?
respond indirectly to PCO2 changes ONLY
pH is inversely related to what?
PCO2
PO2 in venous blood
40 mm Hg
PCO2 in venous blood
46 mm Hg
