Lung: Non-Resp function

Question 1

Name the upper respiratory regions.

Answer 1

Nose, Pharynx, Larynx

Question 2

Name the lower respiratory regions.

Answer 2

TRACHEA , BRONCHI, BRONCHIOLES

Question 3

What does Filtration include?

Answer 3

Filtration: Bronchi, Mucous and ciliation.

Question 4

Name the cell type in Filtration.

Answer 4

Cilia, goblet

Question 5

Name the type of immune response involved in lung and it’s function.

Answer 5

Alveolar macrophage (dust cell):

• Removes dust, fine particles and micro-organisms
• Carbon can become trapped (eg smoking), contributing to COPD

Question 6

What is the main cell type for cilia and goblet cells in the lung in respiratory and olfactory regions, nasopharynx and trachea?

Answer 6

Pseudo-stratified ciliated columnar.

Question 7

What is the common work-related disease found in 1960s-1990s? What are the clinical presentations of this condition?

Answer 7

Pleural Mesothelioma- due to ASBESTOS- construction material in 1960s.

Clinical conditions:

• crackle on inspiration,
• inflammation of cell lining and scarring,
• connective tissue deposits.

Question 8

What is filtration in lung?

Answer 8

It is both both Physical and chemical barriers, where Capillaries is 7µm and larger particles should not pass through.

Also, this act as fibrinolysin activator and stimulates breakdown of clots.

Question 9

What does it called when only 70-100ml is taking part in gas exchange in pulmonary circulation, which holds output from RHS of heart?

Answer 9

Lungs: Blood reservoir

While:

• Vasculature not always fully perfused
• Vessels are distensible and under low pressure

Question 10

Explain the movement of fluid when CO increases.

Answer 10

Pressure from increased cardiac output pushes fluid into the interstitial spaces (osmotic pressure), while fluid drains into lymph.

Question 11

What will be caused if lymphatic system is blocked?

Answer 11

Pulmonary oedema

Question 12

What are the endocrine released by the lung?

Answer 12

1) Histamine: 
Vasodilation and bronchiole constriction
Vascular permeability (leads to pulmonary oedema)

2) Bradykinin: vascular dilator
Inhibited by ACE (Angiotensin Creating Enzyme)

Question 13

How does Renin-Angiotensin-Aldosterone system involve in endocrine released of the lung?

Answer 13

Control of BP as ACE inactivates bradykinin (a vascular dilator)

Question 14

State the metabolism of the lung.

Answer 14

• limited metabolic capacity
• Acts as a buffer: Takes up IV drugs and releases as blood concentrations decrease
• Seratonin and adrenaline are taken up by epithelial cells, and removes vasoactive substances

Question 15

The pH of arterial blood ranges from ___ to ___.

Answer 15

from 7.35 to 7.45

Question 16

State the several mechanisms used to maintain the pH range for acid-base balance.

Answer 16

Buffer systems
Exhalation of carbon dioxide
Kidney excretion of H+

Question 17

Why is it important to keep a narrow pH window?

Answer 17

• Enzymes become irreparably damaged which may affect many metabolic reactions
• affect the ability of Haemoglobin (hb) to carry oxygen
• affect the ionisation of many substances, disrupting their structure e.g. DNA

Question 18

What is buffer system?

Answer 18

A reversible chemical reaction that can absorb or release hydrogen ions (H+) according to the prevailing concentration

– if hydrogen ion concentration is kept constant, pH is kept constant

Question 19

Explain the bicarbonate buffer system.

Answer 19

If pH decreases (hydrogen ion level rises), it combines with bicarbonate to form carbonic acid

If pH increases (hydrogen ion level falls) then carbonic acid dissociates to release more hydrogen ion

Question 20

CO2 mixes with water in the blood to form ____.

Answer 20

carbonic acid (H2CO3).

When carbonic acid level rises, it tends to dissociate into hydrogen ion and bicarbonate ion, and the increased hydrogen ion causes pH to fall.

Increasing ventilation means more carbon dioxide is exhaled, and the equation is reversed, avoiding a change in pH

Question 21

If PaCO2 increases, it is detected by the ___.

Answer 21

carotid chemoreceptors

Question 22

**State the problems with increasing blood acidity, and state the symptoms and treatment for this condition.

Answer 22

“Respiratory Acidosis”

> Symptoms:
Breathing becomes deeper and slightly faster, weak, drowsy, confused, nauseated, [Heart problems, decreased BP leading to shock, coma, and death.]

> Treatment for respiratory acidosis: increase ventilation

Question 23

**Binding of O2 and Hb is ___ dependent. What would happen in low pH?

Answer 23

Binding is pH dependent.

Low pH releases O2 from the hb-O2 complex

Question 24

The intrinsic rhythm of breathing is controlled by areas in the ___ and ___.

Answer 24

pons and medulla

Question 25

State the groups that control breathing.

Answer 25

1) Dorsal Respiratory Group: stimulates diaphragm etc for inhalation

2) Ventral Respiratory Group: forceful breathing:
Stimulates additional inspirational and expirational muscles.

3) Pontine Respiratory Group: modifies VRG
4) Pre-Botzinger complex: rhythm of breathing

Question 26

State the pathway for quiet breathing, in- and exhalation.

Answer 26

DRG:

> Active: Contraction of diaphragm and external intercostal muscles > normal quiet inhalation

> Inactive: Diaphragm and external intercostal muscles relax, elastic recoil of lungs > normal quiet exhalation

Question 27

State the pathway for forceful breathing, in- and exhalation.

Answer 27

> Forceful Inhalation: DRG

1) diaphragm and external intercostal muscles contract
2) activate VRG (forceful inhalation neurones) > contraction of accessory muscles (SCM, scalene, pretrials minor)

> Forceful Exhalation: VRG (forceful exhalation neurones)

-contraction of accessory muscles (internal intercostal muscle, in- & ex-ternal oblique muscles, transverse and rectus abdomenus)

Question 28

State the chemical control of breathing.

Answer 28

in-/decrease PCO2
> chemoreceptors (carotid body)
> respiratory control centre (medulla)
> respiratory muscles
> In-/ decrease frequency and depth of breathing
> De-/Increase stimuli

Question 29

** State the mechanical control of breathing.

Answer 29

“Hering-Breuer Inflation Reflex”

• activated by lung stretch, slowly adapting stretch receptors fire with increasing frequency.
• “inspiratory off-switch”: High receptor activity inhibits further inflation, and expiration begins.

Question 30

**State other control of breathing.

Answer 30

1) Voluntary control:
- communication e.g. speaking, but limited in extent

2) Other CNS areas e.g. for emotion
- Ventilation can be increased or reduced due to emotion; also transient effects such as gasping, sobbing.

Question 31

List of integrated control for CV control centre.

Answer 31

• Heart Rate: BP (baroreceptors)
• Gas Pressure: PO2 /PCO2 (chemoreceptor)
• Temperature
• Motor Cortex
• Skeletal Muscle
• Adrenaline
• Joints