L11

Question 1

Normal gas exchange requires both that alveoli are …. and …. with …. at the appropriate rate

Answer 1

adequately ventilated
perfused
pulmonary blood

Question 2

alveolar ventilation : perfusion ratio:

Answer 2

V delta/Q = Alveolar ventilation rate / Pulmonary blood flow

Question 3

alveolar ventilation : perfusion ratio:

the mean value under normal conditions is aprox…..

Answer 3

0.8

Question 4

Where does this rhythmical activity (breathing) originate?

Answer 4

Breathing is controlled in the brain stem (Medulla and Pons)

Question 5

How is the rate and depth of respiration controlled?

Answer 5

.

Question 6

Wymień Components necessary for rhytmical activity of breathing

Answer 6

• Chemoreceptors for PO2 or PCO2
• Mechanoreceptors in the lungs and joints
• Control centres for breathing
• Respiratory muscles

Question 7

How is the respiratory rhythm generated?

Answer 7

Dorsal and ventral respiratory neuronal groups in the medulla elicit reciprocal activation of the inspiratory muscles (diaphragm and
external intercostal muscles) causing the muscles to shorten and
expanding the volume of the chest

Question 8

During active expiration there is activity of the….

Answer 8

intercostal muscles

Question 9

Opisz the Hering-Breuer reflex

Answer 9

The smooth muscles of the upper airways (trachea, bronchi and bronchioles) have stretch receptors which during inflation send impluses to the dorsal respiratory group via the vagus to inhibit respiration. This is not normally active in quiet respiration but may play a role during exercise.

Question 10

Wymień i opisz factors affecting regulation of respiration apart from the main neurogenic drive (2):

Answer 10

1) Chemical factors
        A rise in Pco2
        A rise in [H+] Chemoreceptors
        Fall in Po2
2)Other neural factors

Question 11

Explain what happens When the O2 in the inspired air falls below 14% (normal 21%) (carotid body)

Answer 11

The resultant hypoxia reduces the synthesis and release of dopamine and the sensory nerve endings
then generate impulses which stimulate the
respiratory centre.

Question 12

Explain what happens While PO2 is within the normal range (carotid body)

Answer 12

dopamine is released, hyperpolarising

the nerve endings and inhibiting their discharge.

Question 13

Carotid body contains…

Answer 13

Contains unmyelinated sensory nerve endings and dopamine containing cells and both are closely
associated with capillaries.

Question 14

Central chemoreceptors adaptations to:

Answer 14

• High altitude
• Chronic respiratory
disease

Question 15

Central chemoreceptors detect …

Answer 15

it detects only hydrogen ion concentration

Question 16

Chemoreceptors (podział i opis)

Answer 16

1. Central
       CSF H+ (minute-minute)
2. Peripheral
       Increased arterial PCO2 (seconds)
       Decreased arterial PO2
       Decreased arterial pH (carotid only not aortic bodies). Longer term metabolic compensation.

Question 17

Respiration is mainly stimulated by: (3)

Answer 17

An increase in PCO2 (hypercapnia)
A change in arterial pH
A lack of oxygen, low PO2 (hypoxia)

Question 18

Respiration actions when increased (Pco2, H+ and acidity)

Answer 18

Fall in CO2
Decrease in plasma [H+]
Respiratory Alkalosis

Question 19

Respiration actions when decreased (Pco2, H+ and acidity)

Answer 19

Rise in CO2
Increase in plasma [H+]
Respiratory Acidosis

Question 20

Wymień REFLEX CONTROL OF RESPIRATION (6):

Answer 20

• Hering-Breuer lung inflation reflex
• Cough and sneeze
• Swallowing
• Pulmonary chemoreflex
• Other neural factors
• Voluntary control e.g. “Ondine’s curse”

Question 21

Wymień Pulmonary chemoreflex causes (3):

Answer 21

Smoking or inhalation of noxious gases
Increase mucus production
Bronchial constriction

Question 22

Wymień Other neural factors (3):

Answer 22

Exercise
Pain
Cold

Question 23

Przypomnienie: Cough and sneeze

Answer 23

Antitussive medications often include the opiate Codine which depresses the “cough centre”. It has side effects such as decreasing bronchiole secretions which thicken the mucus in the lungs and inhibits ciliary activity, reducing clearance from the lungs.

New factors in dark chocolate found to be much more effective but are not yet available clinically.

Question 24

Przypomnienie: Pulmonary chemoreflex

Answer 24

Chemical stimuli acting on irritant receptors on myelinated fibres in the upper airways and/or C-fibre receptors in the lower airways, cause:
coughing
increase mucus production
bronchial constriction

Question 25

The factors that cause pulmonary chemoreflex reactions include;

Answer 25

ammonia, sulphur dioxide, cigarette smoke, and

endogenous inflammatory mediators.

Question 26

Przypomnienie: Voluntary control e.g. “Ondine’s curse”

Answer 26

Bulbar poliomyelitis and certain brainstem lesions result in loss of the automatic regulation of respiration without loss of voluntary control.
Ondine’s curse is a rare and severe form of central sleep
apnea syndrome caused by lack of automatic respiration
control during sleep.

Question 27

WHAT DO THE LUNGS DO? (5 i opisz):

Answer 27

GAS EXCHANGE
Exchange of O2 and CO2 in the lungs

ACID-BASE BALANCE
Acts because lungs regulate the level of CO2 in the blood bicarbonate is an important blood buffer

SPEECH
Due to ability to voluntary control activity of respiratory skeletal muscles and therefore change airflow through the vocal cords

DEFENCE MECHANISMS
Airway warms and humidifies air
Intrinsic cells and some reflexes protect the lungs from pollutants

METABOLISM
Some pulmonary cells modify bioactive materials