W9 - Heart And Lungs Flashcards
Name the stages of the cardiac cycle
Relaxation period
Atria systole & ventricular filling
Ventricular systole
Ventricular diástole
What happens in relaxation period
All 4 chambers are relaxed (in diastole)
What happens in atria systole and ventricular filling
- atria contracts forcing small amount of blood into the ventricle (30%: 20-25 mL)
- at the end of each ventricle contains an EDV (end diastolic volume) = 130ml
- lasts 100msec
- Aortic & pulmonary valves are shut
- atria then enters a state of diastole
What happens in ventricular systole
- ventricles depolarise & ventricles contract
- last 120 msec
- A-V valves pushed closed by blood & ALL valves are now shut for 0.05 secs
- isovolumetric contraction occurs
- ventricular ejection occurs when pressure causes the aortic and pulmonary valves to open
- ventricular pressure decreases & semilunar valves close
What happens in ventricular diastole
- lasts 430 msec
- ALL valves are closed
- isovolumetric relaxation
- lower pressure in ventricles then the atria
- AV valves open so blood pours into the ventricles passively (rapid ventricular filling)
What cardiac output equation
Cardiac output = stroke volume (volume of blood ejected during ventricular systole) x heart rate
What 3 factors govern stroke volume (SV)
Preload : bigger preload (stretch) on cardiac muscle fibres prior to contraction increases their force of contraction
Contractibility : strength of contraction at a given preload
After load : pressure in the blood vessel that needs to be exceeded & increased after load results in reduced SV because more blood remains in ventricles at the end of systole
Home many lobes does the right lung have
3 (upper, middle & outer)
How many lobes does the left lung have
2 (upper & lower)
How many bronchopulmonary segments does the right & left lung have
Right = 10
Left = 8
Name the parts of the upper respiratory tract
Nose
Mouth
Pharynx
Larynx
Name the parts of the lower respiratory tract
Primary bronchi
Secondary bronchi
Tertiary bronchi
Bronchioles
Terminal bronchioles
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
What are the 3 properties of the respiratory system
Compliance: expand ability of the lungs based on the change in volume / change in pressure
Resistance:
Elastic resistance:
Work of breathing (WOB):
Where does the trachea start
Below the larynx C6
Tell me about the trachea
2.5cm diameter, 11cm in length
15-20 C shaped cartilage rings
Divides into 2 branches at the carina T5
Tell me about the primary bronchi
Separated by carina
C shaped cartilage rings
Right trachea is larger then the left trachea and also steeper
Tell me about the secondary bronchi
Right track has 3 serving (upper, middle & lower)
Left track has 2 servings (upper & lower)
Cartilaginous plates
Tell me about the tertiary bronchi
Each supplies air to a single bronchopulmonary segments
Right track has 10 & left has 8-9
More smooth muscle
Less cartilaginous support
Greater tension in the smooth muscle
What 2 cells does alveoli have
Pneumocyte type 1 - responsible for gas exchange
Pneumocyte type 2 - responsible for producing surfactant & differentiating into type 1 cells if there isn’t enough
