CARDIOVASCULAR Flashcards
What is anticipatory rise?
An increase in heart rate before exercise caused by adrenaline.
What is possible risk of having high cholesteral?
Stroke/ cardiovascular disease/ heart attack
Process of the cadiac conduction system:
-Electrical signal sent to SA node
-Causes walls of atria to contract and forces blood into ventricles
-0.1 second delay at AV node for full diastolic filling
-Bundle of HIS
-Purkinje fibres
-Ventricles contract
What are the stages of the sympathetic nervous system?
-Information from receptors sent to cardiac control centre in medualla oblongata
-Down sympathetic nervous system
-SA node, AV node
-Increase heart rate
-Increase in venous return
-Increase in ejection fraction
What is systole?
When the heart contracts and empties
What is disatole?
When the heart relaxes and fills
What do chemoreceptors detect?
-Increase in C02
-Increase in lactic acid
-Decrease pH
What do proprioreceptors detect?
Increase in movement
What do barroreceptors detect?
Decrease in blood pressure
Which two factors affect stroke volume?
-Venous return
-Elasticity of cardiac fibres
What is starling’s law?
-Increased venous return
-Greater diastolic filling phase
-Cardiac muscle stretched
-More force of contraction
-Increased ejection fraction
Cardiac output=
stroke volume x heart rate
What happens to stroke volume during exercise?
-Increases as intensity of exercise increases
-Continues for up to 40-60% of max effort then plateaus
-Increase in HR increases diastolic fillling phase
-Ventricles dont have enough time to fill
What are the stages of cardiovascular drift?
-Occurs after 10 mins of prolonged exercise in warm environment
-Sweat causes water loss in blood cuasing it to go viscous
-Decrease in venous return
-HR increases to maintain cardiac output
Name 4 mechanisms of venous return:
-Skeletal muscle pump
-Pocket valves
-Respiriatory pump
-Cardiac suction pump
What is respiriatory pump?
Inhalation decreases pressure in thoratic cavity and decreases pressure in abdominal cavity. Pressure changes compress nearby veins and assist in blood flow back to heart.
What is systolic pressure?
Pressure in blood vessels when ventricles are contracting
What is diastolic pressure?
Pressure in blood vessels when ventricles are relaxing
What is A-V02 difference?
Difference between the oxygen content in the arterial and venous blood
How does A-V02 difference change during exercise?
-difference increases
-more oxgen is needed in muscles by myoglobin
-oxygen is used for ATP production to increase endurance and aerobic respiration
-Venous blood has less oxygen to return to heart
How is A-V02 diff affected by training?
-Increased musclde myoglobin stores
-Cardiac hypertrophy
Whats makes up a motor unit?
Motor neurone and muscle fibre
What are the features of slow twitch or slow oxidative muscle fibres?
-small neurone size/ few muscle fibres
-low force production
-high capilliary density
-slow contraction speeds
-high myoglobin levels
-high mitochondria levels
-high ressistance to fatigue
What are the features of fast oxidative glycolytic or type 2A?
-Large neaurone size/ lots of muscle fibres
-many cappiliaries
-moderate levels of myoglobin and mitochondria
-fast speed of contraction
-high force of contraction
-moderate ressistance to fatigue
What is tidal volume?
Amount of air breathed in per breath
What is minute ventilation?
The amount of air inspired or expired per minute
How is minute ventilation effected by exercise?
-It will increase
-Working muscles require more oxygen
What does PNF stand for?
Proprioceptive neuromuscular facilitation
What are the two types of proprioreceptors that are involved in PNF?
-Muscle spindles
-Golgi tendon organs
What are the role of the muscle spindles in PNF?
-tell the central nervous system how far and fast muscle is being stretched.
-if stretched too far, triggers stretch reflex and muscle contracts concentrically
What is the role of the golgi tendon organs in PNF?
-Detect levels of tension in the tendon
-Autogenic inhibition occurs which sends signal to brain causing muscle to relax
What are the steps involved in PNF?
-A partner stretches an individuals leg until the muscle spindles inhibit further stretching
-The individual makes the muscle contract isomectrically by pushing against their partner.
-Autogenic inhibition allows the muscle to be stretched beyond the initial range of movement
What are motor units made up of?
Motor neurone and muscle fibre
Name 4 ways you can increase the force of contraction:
-Recruit more motor units
-Recruit larger motor units
-Recruit fast twitch motor units
-Wave summation
What is the all or none law?
Min amount of stimulation to motor unit to make unit contract, if threshold not met then no muscle contracts.
What is wave summation?
Is increasing the strength of contraction by increasing the frequency of the impulse to the muscle.
-The muscle becomes stimulated before it can completely relax.
What is spatial summation?
Involves alternation between contraction and relaxation of motor units.
What is a tetanic contraction?
Impulse arrives at muscle so quickly muscle has no time to relax.
