Transcript Cardiovascular and Respiratory Anatomy

The Cardiorespiratory System
• Size of a fist
• Weighs < .5 kg = 1
pound
• Location
– Midcenter Chest
– 2/3 mass left of
midline
• Anterior to vertebral
column
• Posterior to the
sternum
• 40 million beats per
year
• Pumps 1400 gallons of
blood per day
The Heart
• Heart muscle is
referred to as the
myocardium
• Myo = muscle
• Cardi = heart
• Striated like
Skeletal Muscle
• Differences??
The Heart
• 3 Areas of Heart Tissue
– Atrial – Mechanical Contraction
– Ventricular – Mechanical Contraction
– Conductive – Electrical Transmitter
• Conductive tissue
– Lies between the atria and ventricles
– Facilitates rapid transmission of electrical
impulses
– Transmission allows coordinated actions
between atria and ventricles to pump
Heart Circulation Video
• http://www.youtube.com/watch?v=D3ZDJgFD
dk0&feature=related
2 Separate Pumps That Serve 2
Circulations
• Pulmonary Circuit:
– The right side of the heart
– Receives blood from all parts of the body
– Pumps deoxygenated blood to the lungs
• Systemic Circuit:
– The left side of the heart
– Receives oxygenated blood from the lungs
– Pumps it out to all body tissues
Atria and Ventricles
• Left and Right Atria:
– Superior 2 chambers where blood enters the
heart
– Function as blood reservoirs, delivering blood
into the right and left ventricles
• Left and Right Ventricles:
– Inferior 2 chambers which pump blood away
from the heart
– Thick musculature – Athletes vs. Sedentary
– Forceful contraction powers ejection of blood
through the entire body
Right Atrium
•
3 large veins return blood from the body to the Right
atrium:
– Superior Vena Cava
– Inferior Vena Cava
– Coronary Sinus
• Blood flows R atrium to R ventricle through the
Tricuspid valve:
– Three cusps that allow only uni-directional flow
– Prevents backflow of blood from the right ventricle
to the right atrium when the ventricles contract
(systole)
• As the ventricles contract, blood is forced behind the
3 valve flaps forcing them upward and together to
close the valve
Left Atrium
• Receives Oxygenated blood from
the lungs by the Pulmonary Veins
• Blood flows into the L ventricle
through the L bicuspid or mitral
valve.
• Bicuspid (Mitral) valve prevents
backflow of blood from the L
ventricle to the L atrium during L
ventricular contraction
Right and Left Ventricles
• Actual pumps of the heart
• Right ventricle pumps deoxygenated
blood to the lungs
– Gas exchange occurs at lungs
(respiration)
• The left ventricle ejects oxygenated
blood into the aorta via the systemic
circuit to all body tissues
2 Semilunar Valves
• Located on the arterial walls on the outside of the
ventricles
• Prevent blood from flowing back into the heart
between contractions
• Aortic Semilunar Valve: Left
– Prevents backflow of blood from atria into
ventricles left side of heart during ventricular
relaxation (diastole)
• Pulmonary Semilunar Valve: Right
– Prevents backflow of blood from atria into
ventricles from right side of heart during
ventricular relaxation (diastole)
Heart Valves Video
• http://www.youtube.com/watch?v=H04d3r
JCLCE&feature=related
Path of Blood Through The Heart
• Deoxygenated blood enters R atrium from veins thru
Superior vena cava and Inferior vena cava
– Where has this blood come from and why no 02?
• R atrium → tricuspid valve → R ventricle →
pulmonary semilunar valve → pulmonary arteries →
lungs
• Blood exchanges CO2 for fresh O2 in lungs
– Blood returns to heart via pulmonary veins → L
atrium
• L atrium → bicuspid valve → L ventricle → aortic
semilunar valve → aorta → all arteries of the body
delivering 02, nutrients and carrying away CO2,
waste products
• Back to Step 1…Deoxygenated blood enters R
atrium…..
Conduction System
• The Sinoatrial (SA) Node:
– Pacemaker of heart – sets rhythm
– Normal heart beat begins with an electrical impulse
from the SA (sinoatrial) node
– SA Node located in Upper right atrium
– The impulse spreads throughout the atria, causing them to
contract
• Atrioventricular (AV) Node:
– Electrical impulse travels through the AV
(atrioventricular) node into the conduction fibers
located in ventricles
– Located in lower right atrium
– As the impulse travels down the fibers, the
ventricles contract. The cycle repeats
Electrocardiogram
• An electrocardiogram, EKG
or ECG
– Test measuring
electrical activity of
heartbeat
– Each beat creates, an
electrical impulse (or
“wave”)
– This wave causes
the muscle to contract
and pump blood from
the heart to working
muscles and organs
Electrocardiogram
• P wave:
– Atrial depolarization which initiates atrial
contraction
• QRS complex:
– Ventricular depolarization which initiates
ventricular contraction
• T wave:
– Ventricular repolarization
which represents
electrical recovery
Conduction System Video
• http://www.youtube.com/watch?v=nK0_28
q6WoM&feature=related
Blood Vessels
• Arteries: Transporters
– Transport blood AWAY from the heart. Transport
oxygenated blood only. (*except* in the case of the
pulmonary artery).
• Arterioles: Regulators
– Transport blood from arteries to capillaries.
– Main regulators of blood flow and blood
pressure
• Capillaries: Exchangers
– Exchange of 02, CO2, H2O, hormones,
electrolytes, and other nutrients between the
blood and the surrounding body tissues
– Remove waste products from surrounding
cells
Blood Vessels
• Venules:
– Drains blood from
capillaries into veins,
for return trip to the heart
• Veins:
– Transport blood
towards the heart
– Transport
deoxygenated blood only
(*except* in the case of
the pulmonary vein)
Arteries Vs. Veins
• Transport blood away from
the heart
• Carry Oxygenated Blood
(except Pulmonary Artery)
• Have relatively more
muscle/elastic tissue
• Transports blood under
higher pressure than veins
• Do not have valves (except
for the semi-lunar valves of
the pulmonary artery and the
aorta )
Veins vs. Arteries
• Transport blood towards the heart
• Carry De-oxygenated Blood
Exception -- Pulmonary Vein
• Have relatively less muscle/elastic tissue
• Transports blood under lower pressure (than
arteries)
• Have one-way valves throughout the main
veins of the body
• Valves prevent blood flowing in the wrong
direction, as this could (in theory) return waste
materials to the tissues
•
•
•
•
•
Cardiac Output (Q)
Total volume (amount) of blood
pumped by the heart in one minute
Measured in liters (L) or milliliters
(ml)
Typically males have about 5.5 L of
blood and females 5 L of blood
Why the gender difference??
Product of heart rate (HR) and
stroke volume (SV)
Measuring Cardiac Output (Q)
• Cardiac Output depends on:
– Heart rate (HR): number of times the heart
contracts per minute (60-80 bpm)
– Stroke Volume (SV): the volume of blood
ejected with each stroke or beat (60-80ml)
– Cardiac output computes as follows:
• Cardiac output = Heart rate x Stroke volume
• A-VO2 Difference:
– The difference in the oxygen content of arterial
blood versus venous blood and is expressed in
ml of O2 per 100 ml of blood
Stroke Volume
• SV is determined by:
– End Diastolic Volume (EDV): how much
blood your heart can accommodate
– End Systolic Volume (ESV): how completely
it can empty
• Both EDV and ESV are a result of the
number, size, and the strength of the muscle
fibers
– Left ventricular mass
– Maximal contractility
– How large the blood volume (preload)
– How much the arteries can dilate (afterload)
– Size of the pericardium.
Stroke Volume
• The pericardium is a non-elastic sack around
the heart that may limit maximum filling.
• The lungs could also be a limiting factor in
cases of disease, altitude, or possibly at very
high work loads.
Measuring Cardiac Output
•
For an untrained person who has a resting
heart rate of 72 bpm and a stroke volume of
70 ml the resting cardiac output is:
– Cardiac output = HR x SV
– Cardiac output = 72 x 70
– Cardiac output = 5040 ml/min
– Cardiac output = 5.04 L/min
– (Note: 1000ml = 1L)
• At rest average heart pumps about 5 liters of
blood per minute
Cardiac Output at Rest in Untrained and
Endurance-Trained Males
Heart
Rate in
bpm
Stroke
Volume
(mL)
Untrained 5
70
71
Trained
50
100
Cardiac
Output
(L)
5
Cardiac Output During Exercise in Untrained and
Endurance-Trained Males
Cardiac
Heart Rate Stroke
Output (L) in bpm
Volume
(mL)
Untrained 22
195
113
Trained
195
179
35
Cardiac Output
• Initial Stages of Exercise
 cardiac output is due  heart rate and 
stroke volume
• When level of exercise exceeds 40% to
60% of the individual's capacity, stroke
volume has either plateaued or begun to
increase at a much slower rate
• Further  in cardiac output are largely the
result of  in heart rate.
During exercise, muscles receive 66% of the
cardiac output, but the kidneys only receive 3%!
At rest the liver has the highest percentage of
cardiac output (27%), while the muscles only
receive 15%!
Oxygen Uptake
• Oxygen Uptake (VO2):
–Amount of oxygen utilized by the
tissues of the body
–Measured in liters per minute
(L/min)
–Function of cardiac output
• Maximal Oxygen Uptake is VO2 max:
–Greatest amount of oxygen that can
be utilized at the cellular level for
the entire body
Oxygen Uptake
• Metabolic Equivalent (MET):
–3.5 ml O2/kg/min at rest
• Peak oxygen uptake ranges from
35-80 ml/kg/min or 10-22.9 METS
• Capacity to utilize oxygen is
described by Cardiac Output:
–HR x Stroke Volume and
Arteriovenous Oxygen
Difference (a-vO2 difference)
Men = Blue
Females = Red
Oxygen Uptake (VO2) Calculated
• VO2 = Cardiac Output x a-VO2
difference
– a-v O2 difference = amount of
oxygen extracted from arteries to
veins
–Simply put..how much oxygen is
being used by the tissues.
• Cardiac Output = HR x SV ml/min
Oxygen Uptake Calculated
• Example:
– VO2 at rest = Cardiac output x a-VO2 difference
– VO2 at rest =
• Cardiac output (80 bpm x 65 ml of blood/beat) x
a-VO2 difference (6 ml O2/100 ml blood) =31,200
O2 / min
• 31,200 / 100 = 312
• Then divide 312 ml O2/min by the persons
weight in Kg
• 312 ml o2/min / 75 kg = 4.2 ml O2 kg of BW per
minute
• 4.2 ml/kg/min..What did we say normal was??
Oxygen Uptake Example
• A 30 year-old-male,176-lb has been
running on a treadmill for his aerobic
workouts. His exercise heart rate is 185
bpm, his stroke volume is 110 ml of blood
per beat, and his a-VO2 diff is 13 ml
O2/100 ml blood.
• Remember 1 lb = 2.2 kg and 1 MET = 3.5
ml/kg/min of O2 consumption.
• At what MET level is he exercising?
Oxygen Uptake Example
• VO2 = Cardiac Output (HR x SV) x a-VO2 diff
• VO2 = Cardiac Output (185 beats/min x 110 ml
blood/beat) x a-VO2 diff (13 ml O2/100 ml
blood)
• VO2 = 264, 550 ml
• VO2 = 264, 550/100
• VO2= 2,646 ml O2/min
• 2,646 ml O2/min / 80 kg = 33 ml kg min
• 33 ml kg min / 3.5 METS = 9.4 METS
• VO2 = 9.4 METS
Blood Pressure
• Systolic Blood Pressure:
–Pressure exerted against the arterial
walls as blood is forcefully ejected
during ventricular contraction
–Systole
• Diastolic Blood Pressure:
–Pressure exerted against the arterial
walls when no blood is being forcefully
ejected through the vessels
–Diastole
Blood Pressure
• Blood pressure increases with
dynamic exercise (e.g., walking,
jogging, rowing…)
• In healthy individuals it is only seen in
the systolic response
• During upper extremity exercise both
systolic and diastolic pressures are
higher than compared with lower
extremity exercises
Blood Pressure
• Hypertension:
–High blood pressure commonly
defined as 140/90
• With aerobic exercise systolic
pressure can rise to as much as 220260 mmHg
• Diastolic pressure remains at resting
levels
• Pressure is highest in the aorta and
arteries and rapidly falls in the veins
Cardiovascular Adaptations to
Prolonged Training
• Cardiac Output initially increases
rapidly, then more gradually, and
reaches a plateau
• There is no cardiac output change
with resistance training
• Aerobic and resistance training
increases heart rate
Respiratory System
• Primary function of the respiratory
system is the basic exchange of
oxygen and carbon dioxide
• The respiratory pump:
–located in the thoracic cavity (chest and
abdomen)
–Composed of skeletal structures and
muscles
–Works together with the nervous system
Respiratory System Video
• http://www.youtube.com/watch?v=HiT621
PrrO0&feature=related
Structures of the Respiratory System
• Bones:
– Sternum
– Ribs
– Vertebrae
• Muscles of Inspiration:
– Diaphragm
– External intercostals
– Scalenes
– Sternocleidomastoid
– Pectoralis Minor
• Expiration:
– Internal intercostals
– Abdominals
Structures of the Respiratory System
• Conduction:
–Nasal cavity
–Oral cavity
–Pharynx
–Larynx
–Trachea
–Right and left pulmonary bronchi
–Bronchioles
• Respiratory:
–Alveoli
–Alveolar Sacs
Inspiration
• Diaphragm:
– Large, dome-shaped sheet of striated muscle
– Primary muscle of ventilation
– Creates an airtight separation between the
abdominal and thoracic cavities
– During inspiration the muscle contracts, flattens,
and moves downward toward the abdominal
cavity
– Elongation and enlargement of the chest cavity
expands the air in the lungs
– The lungs inflate as air literally becomes sucked
in through the nose and mouth
Inspiration
• Contraction of the scalenes and external
intercostal muscles between the ribs causes the
ribs to rotate and lift up away from the body
(i.e., handle lifted up and away from the side of
a bucket)
• During exercise:
– The diaphragm descends, the ribs swing
upward, sternum thrusts outward
– Athletes often bend forward from the waist to
facilitate breathing after exhausting exercise
to promote blood flow back to the heart and
minimize effects of gravity
• During Inspiration:
– Chest cavity increases
because the ribs rise
and diaphragm
descends causing air to
move into the lungs
– External intercostals
and scalenes rotate
chest upward and
outward increasing
vertical and anteriorposterior diameters
– Contraction results in a
more negative P which
then causes the lung to
expand (moving air in).
Expiration
• Passive process of movement out of lungs (during
rest and light exercise) due to natural recoil of
lungs and relaxation of inspiratory muscles
• Sternum and ribs swing down
• Diaphragm rises toward thoracic cavity
• This decreases chest cavity volume and
compresses alveolar gas so air moves out of the
respiratory tract into the atmosphere
• During strenuous exercise, internal intercostals
and abdominal muscles act on the ribs to reduce
thoracic dimensions and exhalation is rapid and
extensive
• During
Expiration:
–Ribs swing
down
–Diaphragm
ascends
reducing
thoracic
cavity
volume
–Air rushes
out
Inspiration and Expiration
• Inspiration:
– Contraction of the diaphragm creates
negative pressure (vacuum) in the
chest cavity, and air is drawn into the
lungs
• Expiration:
– The diaphragm relaxes; and the elastic
recoil of the lungs, chest wall, and
abdominal structures compresses the
lungs and air is expelled
Diaphragm Video
• http://www.youtube.com/watch?v=hpgCvW8PRY&feature=related
Control of Respiration
• The nervous system controls the
rate of ventilation by adjusting the
rate and depth of breathing
• The body’s respiratory center is
composed of neurons located in
the lower portion of the brain stem
(pons and medulla oblongata)
Respiratory Responses
• Minute Ventilation:
– The volume of air breathed per minute.
– With aerobic exercise it is increased.
– During exercise it increases from 12-15
breaths per minute at rest to 35-45 breaths
per minute during exercise.
• Tidal Volume:
– The amount of air inhaled and exhaled with
each breath.
– It increases from .4 to 1L at rest to as much
as 3L during aerobic exercise.
Respiratory Responses
• Anatomical Dead Space:
–Air entering and occupying respiratory
passageways that is not useful for gas
exchange. It is about 150 ml in adults
and increases with age.
• Physiological Dead Space:
–Poor blood flow, poor ventilation, or
other problems with the alveoli impair
gas exchange (smoking).
External Influences on
Cardiorespiratory Response
Altitude
• Ventilation rate:
– Total amount of air moving in and out of
the lungs is stimulated at high elevations
by an increase in breath frequency.
• This serves to raise oxygen availability to
the alveoli in the lungs (site of oxygen
extraction from the pulmonary system into
the bloodstream).
Altitude
• Altitude stimulates an increase in heart
rate and cardiac output to increase blood
circulation by the muscles to unload
oxygen and pick up carbon dioxide and
back to the alveoli to reverse these
exchanges.
• The composition of the blood changes
after about 2 weeks of altitude exposure
by producing more red blood cells and
hemoglobin (the iron-protein compound
that transports oxygen).
Altitude
• The benefits of blood adaptation in
the weeks following exposure
includes:
–Reducing the cardiac output required for
oxygen delivery during rest and
submaximal exercise
– Increasing maximal oxygen transport
during strenuous exertion and providing
a larger fluid reserve for sweating.
Physiological Changes With Long-Term
(3-6 months) Aerobic Exercise:
• Bradycardia:
– Slower resting heart rate ranging from 4060 bpm
• Lower maximal heart rate during exercise
• Increase in stroke volume at rest and during
exercise
• Increase in cardiac output at rest and during
exercise
Physiological Changes With Long-Term
(3-6 months) Aerobic Exercise
• Increase in heart volume
• Increase in blood volume
• Increase in systolic blood pressure during
exercise (no change in diastolic)
• Decrease in blood pressure at rest
• Increase in breathing rate (breaths per
minute) during exercise
• Decrease in breathing rate at rest
Physiological Changes With Long-Term
(3-6 months) Aerobic Exercise
• Increase in maximal oxygen uptake
• Onset of blood lactate accumulation
(OBLA) occurs at a higher percentage
• More rapid rate of lactic acid removal
• Increased mitochondrial density and
capillary density
• Improved aerobic enzyme activity
• Decrease in percent body fat