Cardiovascular physiology + respiratory system

Question 1

Pulmonary circulation

Answer 1

Vena cava -> RA -> RV -> Pulmonary arteries -> Lungs -> pulmonary veins -> LA

Question 2

Systemic circulation

Answer 2

LA -> LV -> aorta -> systemic arteries -> body -> systemic veins -> vena cava -> RA

Question 3

Mean arterial pressure

Answer 3

1/3 systole + 2/3 diastole

Question 4

Circulation (pressures + valves)

Answer 4

1. VP<AP (diastole - mitral + tricuspid open)
2. VP>AP (atrial systole - mitral + tricuspid close)
3. VP>AOP (ventricular systole - aortic valve opens)
4. VP<AOP (aortic valve closes)

Question 5

Lub dub sounds

Answer 5

Lub = mitral shutting
Dub = aortic shitting

Question 6

Cardiac output equation

Answer 6

Stroke volume x HR

Question 7

SAN activation

Answer 7

1. Na channels open
2. Threshold hit
3. Ca influx (depolarisation) - slows repolarisation to maintain refractory period
4. K influx (repolarisation)

Question 8

ECG features

Answer 8

P = atrial systole
QRS = ventricular systole
T = ventricular diastole

Question 9

Windkessel effect

Answer 9

Arteries only
1. Blood pumped
2. Arteries stretch increasing volume
3. Elastic recoil at low pressure pushing blood through (pulsatile flow)

Question 10

Starlings forces

Answer 10

HP > OP - fluid from plasma -> interstitial space (arterial end)
HP < OP - fluid from interstitial space -> plasma (venous end)

Question 11

Filtration pressure equation

Answer 11

HP - OP

Question 12

Chronotropic

Answer 12

Heart rate

Question 13

Dromotropic

Answer 13

Conduction speed

Question 14

Inotropic

Answer 14

Contractility

Question 15

Ventricles + autonomic control

Answer 15

Innervated by sympathetic only
Increased contractility - more calcium released in myocytes
Increased work output

Question 16

Vasoconstriction steps

Answer 16

1. Noradrenaline binds α1 activating IP3
2. Calcium activates MLCK
3. Contraction
4. Noradrenaline binds α2 restricting cAMP - inhibits MLCK
5. G1 receptor activates p kinase - inhibiting MLCP

Question 17

Baroreceptor reflex

Answer 17

In aorta + carotid artery
Sympathetic by intermediate cell column
Parasympathetic by vagus
Activate renal medulla

Question 18

Renin

Answer 18

Converts angiotensin -> angiotensin II with ACE catalyst

Question 19

Angiotensin II function

Answer 19

Vasoconstriction
Stimulates aldosterone release - increased sodium and water retention

Question 20

Atrial natriuretic peptide (ANP)

Answer 20

Secreted by atria in response to stretch
Causes vasodilation
Inhibits aldosterone

Question 21

Adenosine

Answer 21

Vasodilator

Question 22

Hypoxia

Answer 22

Adenosine released causing vasoconstriction of pulmonary circulation
Prevented K release by TASK
Na entry - closes K channels
Ca entry
Contraction

Question 23

Breathing

Answer 23

Muscle contraction

Question 24

Ventilation

Answer 24

Movement of air from outside to inside body

Question 25

Automatic breathing

Answer 25

preBotzinger complex (site of inspiration control) - neurones within medulla oblongata RTN/pFRG - involved in active expiration

Question 26

Voluntary breathing

Answer 26

Motor cortex (neurones that modulate breathing in PONS) Can be overridden by medulla

Question 27

Emotional breathing

Answer 27

Originates in limbic system Arises through corticospinal projections

Question 28

Central chemoreceptors

Answer 28

In medulla oblongata Low pH + CO2 levels

Question 29

Peripheral chemoreceptors

Answer 29

In carotid + aortic bodies Low pH, CO2 levels + hypoxia

Question 30

Amygdala

Answer 30

Fear response to CO2

Question 31

Slow adapting stretch receptors

Answer 31

Trachea + bronchi Regulate lung inflation Inhibit inspiration + lengten expriation (Hering-Breur)

Question 32

Hering Breur inflation reflex

Answer 32

Prevent lung over-inflation

Question 33

Rapidly adapting stretch receptors

Answer 33

Epithelial cells in larynx Mechanical stress (large inflation/deflation) Irritants Constricting airway (rapid shallow breathing) Coughing + sighing (lung collapse)

Question 34

Lung compliance

Answer 34

Change in lung volume due to changes in TM pressure Determinants: 1. Stretch of tissues 2. Surface tension in alveoli

Question 35

Post inspiration

Answer 35

Recruitment of muscles to slow down expiration

Question 36

Active expiration

Answer 36

Activation of expiratory muscles

Question 37

Thorax pleural regions

Answer 37

Costal pariental Mediastinal pariental Diaphragmatic pariental

Question 38

Intrapleural pressure

Answer 38

Outside lungs

Question 39

Ohms law

Answer 39

Air moving from a high to low pressure

Question 40

Boyle's law

Answer 40

Increase in lung volume = decreases in alveolar pressure (air in)

Question 41

Inspiration (pressures)

Answer 41

Pip + Palv decrease Ptp increase

Question 42

Expiration (pressures)

Answer 42

Pip + Palv increase Ptp decrease

Question 43

Daltons law

Answer 43

Total pressure = sum of pp

Question 44

RQ equation

Answer 44

CO2 produced/O2 consumed Between 0.7-1

Question 45

O2 transport

Answer 45

At high PO2 Hb binds

Question 46

Bohr effect

Answer 46

High CO2 + H+ shift curve right to promote O2 release

Question 47

CO2 conversion

Answer 47

CO2 + H2O -> H2CO3 -> HCO3- + H+ Catalysed by carbonic anhydrase Cl- shift

Question 48

CO transport

Answer 48

Forms carboxyhaemaglobin Curve shifts left

Question 49

Conducting zone

Answer 49

No gas exchange Warms + moistens air

Question 50

Asthma

Answer 50

Chronic inflammation of smooth muscle in conducing zone Mucus production Treatment: B2 andregenic receptor antagonist

Question 51

Pores of Kohn

Answer 51

In alveoli Prevent collapse

Question 52

Perfusion

Answer 52

Amount of blood -> lungs

Question 53

Ventilation-perfusion mismatch

Answer 53

Ventilation lower than perfusion Optimises gas exchange in different lung regions

Question 54

Emphysema

Answer 54

Self destruction of lungs by proteolytic enzymes secreted by leukocytes Alveoli fuse Collapse of lower airways Increased resistance due to inflammation