Chapter 42 - Circulation and Gas Exchange Flashcards
interstitial fluid
the fluid filling the spaces
in between cells
(ex: composed of water, amino acids, sugars, fatty acids, etc.)
circulatory fluid
hemolymph
it moves material throughout the body
(ex: blood, lymph, etc.)
what is blood comprised of?
plasma
(cells) erythrocytes + leukocytes
(cell fragments) platelets
lymph fluid
a colorless fluid that circulates inside the lymphatic vessels
what are the 3 parts of the cardiovascular system?
1.) pump = heart
2.) tubes = vessels
3.) fluid = blood (also known as hemolymph)
what is another word for hemolymph?
blood
name the 2 heart chambers and briefly describe the function
atria (A) = receives blood from veins
ventricles (V) = pumps blood to arteries
what are the 2 valves in the heart? describe function
atrioventricular (AV) = atria to ventricles
semilunar (SL) = ventricles to arteries
what do valves do in the heart?
they prevent backflow of blood and ensure one-way flow of blood
why is the left side of the heart have a thicker wall?
its thicker because it needs to pump blood to all the body parts
what are the 2 circuits?
pulmonary circuit
systemic circuit
pulmonary circuit
R heart => lungs => L heart
it oxygenates blood
systemic circuit
L heart => body => R heart
delivers oxygenated blood to body
how are electrical signals passed?
via gap junctions
autorhythmic cells
unstable (pacemaker) potential
generate own action potentials
where are autorhythmic cells located mainly?
sinoatrial (SA) nodes
atrioventricular (AV) nodes
syncytium
network of interconnected cells
(ex: cardiac muscle tissue in the atria and ventricles form a syncytium, meaning that individual cells within the heart really function as a unit
why is the sinoatrial (SA) node called the pacemaker of the heart?
because it continuously generates electrical impulses
therefore setting the normal rhythm and rate in a healthy heart
what is the process of electrical conduction of the heart?
1.) signals from the SA node spread through the atria
2.) signals are delayed at the atrioventricular (AV) node
3.) Purkinje fibers (bundle branches) pass signals to the heart apex (at the bottom of the heart)
4.) signals spread throughout the ventricles
intercalated discs
connect adjacent cardiac muscle cells
what are bundle branches?
Purkinje fibers = specialized cardiac muscle cells that conduct electrical impulses
what does an electrocardiogram (ECG) do?
provides an electrical view of the heart
can measure heart rate
what are the electrical events of the cardiac cycle?
1.) P wave = atrial depolarization
2.) QRS complex = ventricular depolarization and atrial repolarization
3.) T wave = ventricular repolarization
what are the levels (#) of heart rate (BPM)?
normal = 60 to 100
bradycardia = < 60
tachycardia = > 100
sinus rhythm
SA node acts as a pacemaker
(P => QRS => T)
arrhythmia
(related to heart rhythm)
faulty nodes or conductance
atria and ventricles contract independently
fibrillation
ectopic (in an abnormal place or position) pacemaker (SA node not in control)
ectopic
in an abnormal place or position
heart block
signals not conducted properly
which side of the heart pumps blood to the lungs? to entire body?
right side of the heart => pumps low oxygenated blood to the lungs where it gets O2
left side of the heart => pumps oxygenated blood to the entire body
cardiac output (CO)
volume (vol) pumped per minute (mL/in.)
heart rate (HR)
number of beats per minute (BPM)
stroke volume (SV)
volume per beat (mL/beat)
how much blood you can pump out per beat
heart strength
stronger heart, stronger stroke volume (SV)
starlings law
“pump what you get” (more in, more out)
venous return
volume returned to the heart
depends on gravity
what are the effects of posture on heart rate (HR)?
1.) seated (resting) = cardiac output (CO) requirement similar to sleeping cardiac output (CO)
increase fitness = increase stroke volume (SV) and decrease heart rate (HR)
2.) seated to standing = lowered venous return (VR) (blood pools in veins in the legs)
decrease stroke volume (SV), cardiac output (CO), and blood pressure
3.) standing to walking = peripheral pump, increase venous return (VR)
increase stroke volume (SV) = decrease heart rate (HR)
baroreceptors (in relation to the heart, like what does it signal the heart to do?)
signals to:
increase heart rate (HR)
arteries => decrease stretch (decrease
pressure)
veins => increase stretch (pooling blood)
what is the main pump?
the heart
what is a peripheral pump?
increases venous return
skeletal muscle and respiratory pump = peripheral pumps
heart = main pump
what is M.A.P.?
mean arterial pressure
how to get M.A.P.?
cardiac output (CO) x total peripheral resistance (TPR)
MAP = CO x TPR
cardiac output (CO)
heart rate (HR) x stroke volume (SV)
CO = HR x SV
diving reflex
optimizes physiology to enable extended underwater time
bradycardia = decreased heart rate (HR)
peripheral vasoconstriction = decreased blood circulation, maintains blood pressure (MAP) with decreased (HR)
peripheral vasoconstriction
decreased blood circulation, maintains blood pressure (MAP) with decreased heart rate (HR)
cardiac cycle
1.) atrial, ventricular diastole
flow: veins => arteries => ventricles
2.) atrial systole, ventricular diastole
flow: atria => ventricles
3.) ventricular systole, atrial diastole
flow: ventricles =>arteries
veins => atria
diastole
relaxation (fill)
systole
contraction (pump)
what are the 2 heart sounds?
“lub” = atrioventricular (AV) valves close
ventricular systole closes atrioventricular (AV) valves
“dub” = semilunar (SL) valves close
ventricular diastole, arterial pressure closes semilunar (SL) valves
sinoatrial (SA) node
pacemaker
generates own action potentials (spontaneous depolarization)
what drives heart contraction?
autorhythmic cells
blood flow (arteries/veins)
arteries => arterioles => capillaries => venules => veins
what preserves blood pressure during diastole?
the elasticity of arteries
arteries
deliver blood (away from the heart)
stores systolic pressure
maintains driving pressure during relaxation (diastole)
what is the capillary flow controlled by?
arteriole diameter (vasoconstriction and vasodilation)
=> narrower blood vessel = less flow
=> widening blood vessel = more flow
precapillary sphincters
vasoconstriction
narrowing of blood vessels
smaller = less flow
vasodilation
widening of blood vessels
wider = more flow
precapillary sphincters
rings of smooth muscle
adjust flow into capillaries
capillaries
exchange of material between the blood and tissue cells (gas, nutrients, and blood cells)
narrow, large surface area, decreased velocity, increase exchange
has thin leaky walls that help with material exchange
capillary exchange
large molecules (cells, proteins)
=> most stay in the blood (plasma)
small molecules (gases, ions, nutrients)
=> through cells = diffusion, membrane
transport
=> around cells = via pores in the
capillary walls
what are the 3 ways things can transport through the capillary walls?
1.) pass through pores
2.) through the membrane via endocytosis or exocytosis (vesicular transport)
3.) diffusion (passes through cells)
fluid
moves through pores in capillary walls
if filtration > absorption then there will be a net loss of fluid
filtration (out)
circulatory => interstitial
blood pressure pushes fluid out
reabsorption (in)
interstitial => circulatory
osmotic pressure pulls fluid back in
osmotic pressure
the pressure caused by a difference in the amounts of solutes/molecules between solutions
lymphatic system
the tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases
returns fluid to the heart
has one-way valves, unidirectional flow, and lymph nodes have an immune function
what happens to blood pressure in capillaries?
blood pressure drops significantly
veins/venules
returns blood to the heart
they have 1-way valves to ensure unidirectional flow (only goes one way)
weak vasoconstriction
strong peripheral pumps
venous return
volume of blood returned to the heart
influenced by gravity
what aides venous return?
muscles in the walls of veins and peripheral pumps
arteriosclerosis
the “hardening of the arteries”
it happens because plaques start forming in the arteries and it causes:
=> reduction of elasticity
=> narrowing
=> reduces blood flow (in the arteries)
hypertension
increased blood pressure
hypotension
low blood pressure
heart attack (myocardial infraction)
blockage in the coronary artery
what can cause heart attacks (myocardial infarctions)?
thrombus => blood clot
myocardial ischemia => inadequate O2 to cardiac muscle
thrombus
blood clot
myocardial ischemia
inadequate O2 to cardiac muscle
what are some treatments for heart attack (myocardial infarction)? describe them.
bypass surgery = adds a vein to create a new route for blood and oxygen to go around a blockage to reach your heart)
stents = small mesh tubes used to hold open passages (weak arteries)
angiogenesis = formation of new blood vessels, using stem cells
angiogenesis
formation of new blood vessels
erythrocytes
red blood cells
leukocytes
white blood cells
true or false: you breathe to feed your mitochondria O2
true
respiratory membrane
connects alveoli and pulmonary capillaries
osmotic pressure
the pressure caused by a difference in the amounts of solutes/molecules between solutions
osmotic pressure
the pressure caused by a difference in the amounts of solutes/molecules between solutions
what are the 2 parts of the respiratory system?
1.) upper = mouth, nasal cavity, pharynx, and larynx
“conditions” air => adds moisture to the air, removes moisture from the air, or heats and cools the air
2.) lower = trachea, bronchi, bronchioles, and alveoli
true or false: lungs are never completely empty
true
(lungs) tidal volume
normal breath
(lungs) vital capacity
maximum inhale and maximum exhale
(lungs) residual volume
air remaining following exhale (“used” air mixes with “new” air)
what does altitude do?
influences total air pressure
doesn’t change the composition of the air (% of each gas is the same)
slows diffusion
partial pressure (Pgas)
the pressure exerted by a particular gas in a mixture
equation:
Px = (Ptotal) x (%gas)
what are the 2 ways oxygen is transported?
1.) hemoglobin (Hb) = 98% transport
2.) plasma = 2% transport
oxyhemoglobin
oxygen + hemoglobin
O2 + Hb = oxyhemoglobin
cooperativity
binding at one site influences binding at others, like a bandwagoning of molecules
(ex: when 1 oxygen molecule binds onto a hemoglobin molecule, the rest of the oxygen molecules all start binding)
enhances binding and release (speed up the process since 1 oxygen molecule has signaled to other molecules that they found the binding site)
Bohr shift
changes in the O2 dissociation curve as a result of CO2 levels
when an increase in CO2 production lowers pH and induces increased O2 release from hemoglobin (Hb)
what happens when there is an increase in CO2 production?
pH decreases
increase O2 release from Hb
increase metabolic activity <=> increase O2 delivery due to metabolic activity
what are the 3 ways CO2 is transported?
1.) hemoglobin (Hb) = 33%
(33% is how much CO2 uses Hb for transport)
2.) plasma = 7%
3.) bicarbonate = 70%
what enzyme is used to convert CO2 to HCO3- (bicarbonate)?
carbonic anhydrase
why is the sinoatrial (SA) node called the pacemaker of the heart?
because it continuously generates electrical impulses
therefore setting the normal rhythm and rate in a healthy heart
