1.2 - Cardiovascular And Respiratory Systems Flashcards
What does the pulmonary circuit do?
Carries deoxygenated blood back to the lungs and oxygenated blood back to the heart.
What does the systemic system do?
Carry oxygenated blood to the body and deoxygenated blood back to the heart.
Describe the conduction system. (5)
Sino atrial node generates an electrical impulse and fires it across the atria walls.
This is collected by the AV node which delays it by 0.1 seconds to allow the atria to finish contracting.
The bundle of HIS then collects the impulse and carry’s it to the base of the ventricles via the bundle branches.
The punkijne fibres are found at the bottom of the ventricles.
They distribute the impulse around the ventricle walls to cause contraction.
Describe the atrial systole phase of the cardiac cycle.
Lasts 0.1 seconds
Atria contract to force the remaining blood into the ventricles.
Describe the ventricular systole phase of the cardiac cycle.
Lasts 0.3 seconds
AV valves close, semi lunar valves open, allows blood to leave heart.
Ventricles contract, increasing pressure to close AV valves to prevent back flow into atria.
Semi lunar valves forced open as blood is ejected from ventricles into aorta and pulmonary artery.
What happens in the diastole phase of the cardiac cycle. (5)
Lasts 0.4 seconds
AV valves open, semi lunar valves close in order for chambers to fill.
Pressure in atria increase, opening AV valves.
Blood passively enters the ventricles
Semi lunar valves are closed to prevent blood from leaving the heart.
What is stroke volume
The volume of blood ejected from then left ventricle per beat
What is the average resting heart rate
72bpm
What is venous return
The return of blood to the right atria through the veins
What are the 2 factors that stroke volume is dependant on
Venous return
Ventricular elasticity
What is sub-maximal exercise
Exercise which is a low to moderate intensity within a performers aerobic capacity ie below the anaerobic threshold. Associated aerobically.
What is maximal exercise
Exercise which is at a high intensity above a performers aerobic capacity which will take a performer to exhaustion. It is associated with anaerobic work and fatigue.
Explain the frank starling mechanism
Increased Venous return leads to an increased stroke volume, due to an increased stretch on the ventricle walls and therefore the force of contraction
What are the 3 control mechanisms
Neural control
Intrinsic control
Hormonal control
What is neural control
Chemoreceptors - located in aorta, carotid arteries and muscles - inform CCC of chemical changes eg CO2
Propioreceptors - located in the muscles, tendons and joints inform the CCC of movement or motor activity
Baroreceptors - located in blood vessel walls - inform CCC of change in blood pressure
What is intrinsic control
Increased temperature
Increased venous return
What is hormonal control
Synthetic release of adrenaline and non adrenaline
What is the sympathetic nervous system
Part of the ANS which is responsible for increasing heart rate
What is the parasympathetic nervous system
Part of the autonomic nervous system responsible for decreasing heart rate
What is the structure of veins
Thin Layer of small muscle tissue
Pocket valves
Wide lumen
What is the structure of arteries
Narrower lumen
Thick muscular walls
What are the 5 mechanisms of venous return
Pocket valves, smooth muscle, gravity, muscle pump, respiratory pump
What is the definition of vascular shunt mechanisms
The redistribution of cardiac output around the body from rest to exercise which increases the percentage of blood flow to the skeletal muscles.
What is the structure of the respiratory system (7)
Pharynx
Nasal cavity
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
What’s the mechanics of inspiration at rest (5)
External intercostals contract
Rib cage and sternum pushes up and out
Diaphragm contracts and flattens
Volume inside the thoracic cavity increases
This lowers the pressure so air rushes in
What are the mechanics of inspiration during exercise
Sternoclaidomastoid and pectoralis minor are also recruited
Creates a greater up and outward movement of the rib cage
Increases volume
Decreases pressure
Increase depth of breathing and therefore volume of air inspired
What are the mechanics of expiration at rest?
External intercostals relax, lowering the rib cage and sternum down
Diaphgram relaxes and returns back to dome shape
Volume inside thoracic cavity decreases
Pressure increases
Air rushes out
What are the mechanics of expiration during exercise?
Additional muscles can be recruited to give a larger force of contraction:
- internal intercostals
- rectus abdominis
What does the RCC do?
Receives information from the sensory nerves to change the rate of respiratory muscle contraction
What are the 2 centres within the RCC? What is the function of each?
Inspiratory centre - stimulate inspiratory muscles to contract at rest and during exercise
Expiratory centre - is inactive at rest, but will stimulate additional expiratory muscles during exercise
Which nerve causes the external intercostals and the diaphgram to contract?
External intercostals - intercostal nerve
Phrenic nerve - diaphgram
How do chemoreceptors work in the RCC?
Located in aorta and carotid arteries pick up an increase in blood acidity, increase in CO2 concentration and decrease in O2 concentration
What do themoreceptors do in the RCC?
Inform of an increase in blood temperature
What do proprioreceptors do in the RCC?
Inform of motor activity
What do Baroreceptors do in the RCC?
Located in lung tissue and bronchioles, inform of the state of lung inflation
What are the 2 sites where gaseous exchange occurs?
Between alveoli and capillary membrane - external site
Between capillary and muscle cell membrane - internal site
What is gaseous exchange?
Movement of gases by diffusion from an area of high partial pressure to lower partial pressure down the concentration gradient
What is external respiration ?
Exchange of deoxygenated blood in capillaries and oxygenated air held in alveoli
What is internal respiration?
Exchange of gases at muscle cells between oxygenated blood in capillaries and carbon dioxide within muscle cells
What are 4 effects which result in the Bohr shift occuring?
Partial pressure of oxygen lowering
Increases in temperature
Increases in production of CO2
Increases production of lactic acid and carbonic acid
What is the Bohr shift?
Move in the oxyhaemoglobin curve to the right
