Physiology Khogali prep

Question 1

Respiratory causes of SOB

Answer 1

asthma
COPD
pneumonia
lung cancer
pulmonary fibrosis
pleural effusion
pneumothorax

Question 2

cardiovascular causes of SOB

Answer 2

heart failure: IHD, hypertension, valvular heart disease, cardiomyopathy, arrhythmias
pulmonary embolism

Question 3

other causes of SOB (not resp or cardio causes)

Answer 3

anaemia
acidosis e.g. lactic acidosis, diabetic ketoacidosis
panic attacks
exercise
obesity
pregnancy

Question 4

what/where are the respiratory centres in the brainstem?

Answer 4

pons and medulla

(respiration modified by inputs from pons, respiratory rhythm generated in medulla)

Question 5

-

Answer 5

central chemoreceptors
peripheral chemoreceptors

Question 6

where are stretch receptors found in resp

Answer 6

in the walls of bronchi and bronchioles

Question 7

which receptors are stimulated by pulmonary capillary congestion and pulmonary oedema; also pulmonary emboli —-> rapid shallow breathing

Answer 7

juxtapulmonary receptors

Question 8

which receptors lead to increased ventilatory rate in response to decrease BP

Answer 8

baroreceptors

Question 9

where are central chemoreceptors situated

Answer 9

near the surface of the medulla of the brainstem

Question 10

central chemoreceptors respond to the __________ concentration of the ____

Answer 10

hydrogen
CSF

Question 11

does CSF contain more or less protein than blood

Answer 11

less

Question 12

what separates the CSF from the blood

Answer 12

blood brain barrier

Question 13

the blood brain barrier is relatively impermeable to ____ and _______.
____ diffuses readily.

Answer 13

impermeable to H+ and HCO3-

CO2 diffuses readily

Question 14

what is hypercapnia

Answer 14

too much carbon dioxide (CO2) in your blood

Question 15

the hypoxic drive of respiration effect is all via the ___________ chemoreceptors

Answer 15

peripheral

Question 16

when might the hypoxic drive of respiration become important?

Answer 16

• patients with chronic CO2 retention (e.g. COPD)
• high altitudes

Question 17

does H+ readily cross the blood brain barrier

Answer 17

no

Question 18

peripheral chemoreceptor stimulation by hydrogen causes hyperventilation and increases elimination of ____ from the body

Answer 18

CO2

Question 19

what is the effect of increased PCO2 in the arterial blood on the central chemoreceptors?

Answer 19

strongly stimulates the central chemoreceptors; is the dominant control of ventilation

Question 20

in inspiration, the volume of the thorax is increased vertically by contraction of the ___________

Answer 20

diaphragm

Question 21

the ___________ ___________ muscle contraction lifts the ribs and moves out the sternum

Answer 21

external intercostal

Question 22

what is the “bucket handle” mechanism?

Answer 22

the external intercostal muscle contraction lifts the ribs and moves out the sternum

Question 23

what are the major muscles of inspiration?

Answer 23

The diaphragm and the external intercostals

Question 24

what are the accessory muscles of respiration?

Answer 24

The accessory inspiratory muscles are the sternocleidomastoid, the scalenus anterior, medius, and posterior, the pectoralis major and minor, the inferior fibres of serratus anterior and latissimus dorsi, the serratus posterior superior may help in inspiration also the iliocostalis cervicis

The accessory expiratory muscles are the abdominal muscles: rectus abdominis, external oblique, internal oblique, and transversus abdominis.

Question 25

what are the three important pressures in ventilation

Answer 25

atmospheric pressure intra-alveolar pressure intrapleural pressure

Question 26

forces keeping the alveoli open

Answer 26

- transmural pressure gradient - pulmonary surfactant - alveolar interdependence

Question 27

forces promoting alveolar collapse

Answer 27

- elasticity of stretched pulmonary connective tissue fibres - alveolar surface tension

Question 28

primary determinant of airway resistance is the ________ of the conducting airway

Answer 28

radius

Question 29

airway resistance: parasympathetic stimulation causes _______________________

Answer 29

bronchoconstriction

Question 30

airway resistance: sympathetic stimulation causes _______________________

Answer 30

bronchodilatation

Question 31

what happens to intrapleural pressure during inspiration

Answer 31

it falls.

Question 32

what happens to intrapleural pressure during expiration

Answer 32

it rises

Question 33

what is dynamic airway compression

Answer 33

occurs when the pressure surrounding the airway exceeds the pressure within the airway lumen.

Question 34

what is lung compliance

Answer 34

compliance is a measure of the effort that has to go into stretching or distending the lungs. the less compliant the lungs are, the more work is required to produce a give degree of inflation

Question 35

give an example of a factor that could decrease lung compliance

Answer 35

pulmonary fibrosis

Question 36

situations when work of breathing is increased (5 points)

Answer 36

- when pulmonary compliance is decreased - when chest expansion is restricted - when airway resistance is increased - when elastic recoil is decreased - when there is a need for increased ventilation

Question 37

what do alveoli walls consist of

Answer 37

a single layer of flattened Type I alveolar cells

Question 38

what encircle each alveolus

Answer 38

pulmonary capillaries

Question 39

four factors that influence the rate of gas transfer across the alveolar membrane

Answer 39

- partial pressure gradients of O2 and CO2 - surface area of the alveolar membrane - thickness of the barrier separating the air and blood across the alveolar membrane - diffusion coefficient

Question 40

gas exchange abnormalities

Answer 40

hypoxia and hypercapnia

Question 41

what is functional residual capacity

Answer 41

the volume remaining in the lungs after a normal, passive exhalation

Question 42

what is cardiac output

Answer 42

the volume of blood pumped by each ventricle per minute

Question 43

cardiac output equation

Answer 43

CO = SV x HR

Question 44

what is stroke volume

Answer 44

the volume of blood ejected by each ventricle per heart beat

Question 45

stroke volume equation

Answer 45

SV = EDV - ESV

Question 46

What is the end diastolic volume determined by

Answer 46

the venous return to the heart

Question 47

what does the frank-starling curve state

Answer 47

the more the ventricle is filled with blood during diastole (EDV), the greater the volume of ejected blood will be during the resulting systolic contraction (stroke volume)

Question 48

what is chronic heart failure

Answer 48

a complex syndrome that can result from any structural or functional cardiac disorder that impairs the pumping ability of the heart

Question 49

what is the leading cause of heart failure

Answer 49

coronary artery disease

Question 50

in anaemia, would the arterial PO2 be low, normal or high?

Answer 50

normal