1.2 - Cardiovascular and Respiratory Systems Flashcards
pulmonary circuit definition + role
circulation of blood through the pulmonary artery to the lungs and pulmonary vein back to the heart
- carries deoxy blood to lungs and oxy blood back to the heart
systemic circuit definition
circulation of blood through the aorta to the body and vena cava back to the heart
- carries oxy blood to the body and deoxy blood back to the heart
why does the left side of cardiac muscle have thicker muscular walls?
so it can contract with more force as it is sending oxygenated blood to the rest of the body
left side of the heart
- blood oxygenated at lungs and brought back to left atria through pulmonary vein
- oxygenated blood moves from left atria through the left AV valve into the left ventricle to be forced out into the aorta
- aorta carries oxygenated blood to muscles and organs
right side of the heart
- deoxygenated blood from the muscles and organs arrives back at the right atria through the vena cava
- it moves from the right atria, through the right AV valve into the right ventricle to be forced out into pulmonary artery
- pulmonary artery carries deoxy blood to lungs
myogenic definition
capacity of the heart to generate its own electrical impulse, which causes the cardiac muscle to contract
the conduction system definition
set of 5 structures which pass the electrical impulse through the cardiac muscle in a coordinated system
part 1 of conduction system
- SA node - located in right atrial wall, SA node generates the electrical impulse and fires it through the atria walls = they contract
part 2 of conduction system
AV node - collects the impulse and delays it for approximately 0.1 seconds to allow the atria to finish contracting
- then releases the impulse to the bundle of HIS
part 3 of conduction system
bundle of HIS - located in the septum, bundle of HIS splits the impulse in two, ready to be distributed through each separate ventricle
part 4 of conduction system
bundle branches - they carry the impulse to the base of each ventricle
part 5 of conduction system
purkinje fibres - these distribute the impulse through the ventricle walls, causing them to contract
Diastole process
- as atria and ventricles relax, they expand, drawing blood into the atria
- pressure in atria increases, opening the AV valves
- blood passively enters the ventricles
- SL valves are closed to prevent blood from leaving the heart
atrial Systole process
- atria contract, forcing remaining blood into ventricles
ventricular systole process
- ventricles contract, increasing the pressure closing the AV valves to prevent backflow into the atria
- SL valves are forced open as blood ejected from ventricles into aorta and pulmonary artery
heart rate
number of times heart BPM
220 - age
stroke volume
volume of blood ejected from heart per beat
average is 70ml
venous return
volume of blood returning to the heart
- higher venues return = more blood available in ventricles for ejecting
higher ventricular elasticity and contractility =
higher the force of contraction = higher stroke volume
cardiac output
volume of blood pumped out of the heart per minute
HR x SV
what is sub maximal exercise?
low to moderate intensity within a performers aerobic capacity or blow the anaerobic threshold
- heart rate likely plateaus after supply of oxygen delivery meets demand
what is maximal exercise?
high intensity above a performers aerobic capacity, which will take a performer to exhaustion
how does stroke volume change when we exercise?
increases in proportion until plateau
increases because of:
- increased venous return
- frank starling mechanism - increased vol of blood back to heart = increased end diastolic volume in ventricles = greater stretch = more force ventricular contraction = ejecting a larger volume of blood
why does stroke volume reach a plateau during sub - maximal intensity?
- increased heart rate towards max intensities doesn’t allow enough time for the ventricle to completely fill with blood in the diastolic phase = limited frank - starling mechanism
neural control
- chemoreceptors located in the muscles, aorta and carotid arteries inform the CCC of chemical changes in the blood stream, such as increased levels of CO2/ lactic acid
- proprioreceptors located in the muscles, tendons and joints inform the CCC of motor activity
- baroreceptors located in the blood vessel walls inform the CC of increased BP
intrinsic control
- temperature changes will affect the viscosity of the blood and speed of nerve impulse transmission
- venous return changes will affect the stretch in the ventricle walls, force of ventricular contraction and so SV changes
hormonal control
adrenaline and noradrenaline are released from the adrenal glands increasing the force of ventricular contraction and the spread of electrical activity through the heart increases
CCC actions either an
increase or decrease in stimulation of the SA node, which will raise or lower heart rate
when is the sympathetic nervous system actioned?
releasing adrenaline, noradrenaline and sending stimulation to the SA node via he accelerator/ cardiac nerve = increase heart rate
when is the parasympathetic nervous system actioned?
to inhibit the effects of the sympathetic nervous system via the vagus nerve
= decrease heart rate
what is the role of the plasma?
- transport nutrients such as oxygen and glucose
- protect and fight disease
- maintain internal stability of body and regulate temperature
characteristic of arteries?
- large layer of smooth muscle and elastic tissue to cushion and smooth the blood flow, also allow vasodilation/constriction
characteristics/ role of capillaries?
- bring blood in close contact with muscle and organ cells for gas change
- single layered wall
characteristics of veins and venules?
- small layer of smooth muscle to vasoconstrictor/dilate
- valves to prevent back flow of blood as blood is going against gravity
mechanisms of venous return
- pocket valves - prevent backflow
- smooth muscle
- gravity
- muscle pump
- respiratory pressure
vascular shunt mechanism definition
under control of the VCC
- redistribution of cardiac output around the body from rest to exercise which increases the percentage of blood flow to skeletal muscles
function of arterioles
blood vessels carrying oxygenated blood from the arteries to the capillary beds which can vasodilate or and vasoconstrict to regulate blood flow
- ones serving capillary beds around muscles dilate during exercise
pre-capillary sphincters role
rings of smooth muscle. at the junction between arterioles and capillaries, which can dilate or contract to control blood flow through the capillary bed
- ones serving capillary beds around muscles dilate during exercise
vasomotor tone definition
partial state of smooth muscle constriction in the aerial walls
VCC receives information from:
- located in the medulla oblongata
- chemoreceptors regarding chemical changes, such as CO2 and lactic acid rising during exercise
- baroreceptors regarding pressure changes on the arterial walls
increased stretch on walls + co2/ lactic rising =
sympathetic stimulation decreased at muscle cells and vasodilate
sympathetic stimulation increased near organ cells
two main functions of respiratory system?
- pulmonary ventilation - inspiration and expiration of air
- gaseous exchange
- external respiration: movement of oxygen into the blood stream and co2 into lungs
- internal respiration: release of O2 to respiring cells for energy production and collection of waste products
pathway of air?
- air drawn into nasal cavity through noe
- travel into pharynx, larynx and trachea, the surfaces of which have mucous membrane + ciliated cells, which moisten warm and filter air before entering lungs
- trachea splits into two bronchi, which splits into bronchioles and end in alveolar ducts
- this is entrance for air to move into alveoli
two ways oxygen can be transported
- carried within haemoglobin
2. carried within blood plasma (only 3%)
3 ways co2 can be transported
- dissolved in water and carried as carbonic acid - 70%
- carried within haemoglobin as carbaminohaemoglobin - 23%
- dissolved in blood plasma - 7%
minute ventilation definition + formula
volume of air inspired or expired per minute
VE = TV X F(breathing rate) litres per minute
tidal volume response to exercise
increases initially in proportion, reaches a plateau as breathing rate at maximal intensities does not allow enough time/ too much muscular effort for maximal inspirations/expirations
minute ventilation response to exercise and recovery
- initial anticipatory rise in VE due to adrenaline
- rapid increase initially
- steady state VE throughout sustained intensity exercise as oxygen supply meets demand
- initially rapid and then more gradual decrease in VE to resting levels as recovery is entered and the demand for oxygen reduces steeply
mechanics of inspiration at rest
two muscles largely responsible to increase volume of thoracic cavity
- intercostals contract lifting ribs up and out
- diaphragm contracts and flattens
= volume increases = pressure decreases = air moves in from high P to low P
mechanics of inspiration during exercise
demand for O2 increases. production of CO2 increases
- sternocleidomastoid
- pectoralis minor
both increase up and outward movement of rib cage.
mechanics of expiration at rest
passive process
intercostals and diaphragm relax, ir forced out
mechanics of expiration during exercise
internal intercostals + rectus abdominis contract to force air out quicker, increasing the rate of breathing
what is the RCC and what are the centres in it?
respiratory control centre
- inspiratory centre - stimulates inspiratory muscles to contract at rest and during exercise
- expiratory centre - inactive at rest but stimulates expiratory muscles to contract during exercise
intercostal nerve to + phrenic nerve to
external intercostals + diagphragm
exact respiration cycle doing rest
nerve impulses stimulate inspiratory muscles to contract
thoracic cavity volume increases and air will be inspired
simulation stops and inspiratory muscles relax
lung tissues recoil and passive expirations occurs
partial pressure
pressure exerted by an individual gas held in a mixture of gases
gases move from high partial pressure to lower partial pressure through diffusion
external respiration
exchange of gases at lungs between deoxygenated blood at capillary/alveoli boundary
- basically gas exchange - haemoglobin molecules associate with oxygen molecules to form oxyhemoglobin
internal respiration
exchange of gases at muscle cells between the oxygenated blood that arrives in capillaries with co2 producing muscle cells
- haemoglobin molecules dissociate the oxygen for diffusion as they pass muscle cells
- co2 diffuses from muscle cells into the capillary
internal respiration
muscles tissues demand for oxygen increases = more aerobic = more co2 waste product produced = lower po2 and higher pco2, diffusion from high to low, so high po2 diffuse to low po2 in muscle cell
oxyhemoglobin dissociation curve
graph showing relationship between po2 and % saturation of haemoglobin(%of o2 dissociated from haemoglobin)
Bohr shift
move in oxyhemoglobin dissociation curve due to increases in temp/ co2 production/ prod of lactic acid
Haemoglobin
Protein that is able to carry 4 oxygen molecules
Haemoglobin + oxygen = oxyhaemoglobin
What is blood pooling?
Blood pooling is where blood may sit in pocket valves and ‘pool’ / accumulate. This often occurs if we suddenly stop exercising and immediately rest. To aid venous return and prevent blood pooling, we should perform an active cool down.
the more efficient a body’s cv system the
greater the capacity to transport oxygen to the muscles and the greater the capacity to remove waste products from the muscles, such as CO2 and lactic acid
chemoreceptors located
in the aorta and carotid arteries pick up an increase in blood acidity, increase in co2 conc. and a decrease in o2 conc.
thermoreceptors
inform of an increased blood temperature
proprioreceptors
inform of motor activity in the muscles and joints
baroreceptors
located in the lung tissue and bronchioles, inform of the state of lung inflation
heart rate response to exercise
- initial anticipatory rise in HR prior to exercise due to the release of hormone adrenaline
- rapid increase in HR at the start of exercise to increase blood flow and oxygen delivery line with exercise intensity
- a steady state HR throughout the sustained intensity exercise as oxygen supply meets demand
- initial rapid decrease in HR as recovery is entered and the action of the muscle pump reduces
- a more gradual decrease in HR to resting levels
submaximal
heart rate can plateau, supply meets demand
maximal
HR does not plateau as exercise intensity increases, growing demand + supply
heart rate regulation
ANS - automatic nervous system determines firing rate of SA node
CCC receives info from sensory nerves and sends direction through motor nerves to change HR
