Lecture 19 respiratory system

Question 1

Why study respiration?

Answer 1

Essential for life: Provides O2 and removes CO2 to ensure correct cellular functioning (gas exchange).

Breathing is the basis for multiple critical behaviours: speaking, olfaction, emesis (vomiting).

Strong links to emotional centers in the brain.

Question 2

Terminology notes

Answer 2

Respiration = ventilation = breathing
Inspiration = a breath in
Expiration = breathing out

Question 3

Describe the main function of the respiratory system.

Answer 3

See other cards

Question 4

Discuss the brainstem regulation of breathing and stimuli that influence breathing.

Answer 4

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Question 5

Discuss the brainstem regulation of breathing and stimuli that influence breathing.

Answer 5

See other cards

Question 6

How gas exchange occurs

Answer 6

Fresh air (21% O2, ~0.05% CO2) enters the lungs during inspiration.
The low O2 and high CO2 blood entering the lungs from the body has the O2 replenished and CO2 removed by diffusion in the alveoli.
The high CO2/low O2 (~13% O2, ~5% CO2) air is breathed out of the lungs during expiration.

SUPPLEMENT YOUR BIO KNOWLEDGE

Question 7

Respiratory system anatomy

Answer 7

see illustration in slides

Question 8

Difference between inspiration and expiration

Answer 8

Inspiration
Active, diaphragm and intercostal muscle activation.
Expiration
Passive at rest, relies on recoil of the lungs/chest wall.
Active during exercise/stress using abdominal muscles.

there is a graph

Question 9

Need to learn the areas of your spinal cord

Answer 9

LEARN IT!

Question 10

Neural innervation

Answer 10

Phrenic nerves innervate diaphragm. Cervical spinal cord (C3-C5).
Intercostal nerves innervate intercostal muscles. Thoracic spinal cord (T1-T11).
Accessory muscles (abdomen for example) activated during high work/cough. Lumbar spinal cord.

Question 11

What brain strucutres are responsible for controlling breathing

and where are they anatomically

Answer 11

The main respiratory pattern generator (pacemaker) is located in the Pre Botzinger complex.
The region of the brain that responds to CO2 is the retrotrapezoid nucleus (RTN also called parafacial respiratory group - pFRG).
O2 and CO2 are also sensed in the peripheral arteries and these signals are sent to the RTN via nerves.

Question 12

There is a difference between dorsal and ventral groups

Answer 12

i don’t remember

Question 13

Inputs to the respiratory centres

Answer 13

Peripheral
Chemosensors: through the RTN
Lung irritant and stretch: through DRG

Question 14

Inputs to the respiratory centres

Answer 14

Central (supramedullary): primarily via PRG 
Volitional, Pain, Temperature, Emotion
Speech, Swallow, Cough, Sneeze, Hiccup
Sleep, Exercise, Defecation, Parturition
Panting, sonar (animals)

Question 15

Emotions and respiratory control

Answer 15

Amygdala – Pontine respiratory group (PRG) connection such that emotional stimuli result in respiratory rate increase.
Amygdala – DRG connection that results in inspired volume (and cardiovascular) increase.
Fear/anger: increase respiratory rate and sometimes depth
Positive affect: slow and deep (excited) or shallow (calm)
Bi-directional links: Basolateral amygdala (and hypothalamus) also CO2 sensitive.

Question 16

Panic Disorder

Answer 16

Defined as: frequent, unexpected acute panic attacks
Panic attack: episode (~30min) of overwhelming anxiety and distress with:
Air hunger, shortness of breath, Hyperventilation

Question 17

Low CO2 symptoms

Answer 17

ABDOMEN:nausea, cramping
CONSCIOUSNESS:dizziness, fainting, confusion, disorientation
HEART:palpitations, increased rate, angina symptoms, arrhythmias
MUSCLES:spasm, weakness, fatigue
PERIPHERAL CHANGES:trembling, shivering, sweatiness, coldness, tingling, and numbness;
SENSES:blurred vision, dry mouth, sound seems distant, reduced pain threshold;
RESPIRATION:shortness of breath, bronchial constriction/spasm, feelings of suffocation, air hunger
VASCULAR:hypertension, migraine, palor

Question 18

Respiratory findings in Panic Disorder

Answer 18

Suffocation “false alarm” hypothesis
Heightened responsiveness to CO2
Increased sigh frequency
Increased central apnea in sleep

cycle of stress and overbreahting see graph in slides

Question 19

how to cope with panic attacks

Answer 19

breathe back your carbon dioxide

paper bag, cover your mouth

Question 20

Breath holding spells

Answer 20

Involuntary breath holding in toddlers during a tantrum/when very upset.

The turn blue, can pass out and have a seizure.
Prevalence ~ 5% of toddlers.

The emotional input to the respiratory controller is very strong!

Question 21

Dyspnea and mood

Answer 21

Dyspnea is a term for the discomfort associated with being short of breath/breathless.

Sharma JAP 2015

20 healthy adults did 6 x 5 minute exercise tests (brisk steep walk) on 3 days while viewing positive, negative or neutral images.

Every minute during the tests they rated mood (valence and arousal) and dyspnea (intensity and bothersomness)

Question 22

Positive mood improved dyspnea

Answer 22

see slides for more detail

basically what was said

Question 23

Deep breathing and stress

Answer 23

Many Eastern traditions consider breath practices as fundamental to physical, emotional, and spiritual health.
Tai Chi, Yoga, Qigong, meditative breathing.
Different types: Slow breathing, laryngeal closure, breath holding.
Relaxing will increase
parasympathetic/vagal nerve activity, reduces cortisol secretion.

Question 24

Busch et al. Pain Med 2012

Answer 24

Compared the effect of relaxing versus attentive deep slow breathing on pain threshold, autonomic activity and mood.

Pain threshold increased and sympathetic activity decreased with relaxed deep breathing only.

Deep breathing effects mood, relaxation changes pain threshold

however no significnt difference in reduction of negative emotinos

Question 25

Summary

Answer 25

The main function of breathing is to replenish O2 and wash out CO2.
Breathing is controlled in the brainstem but has strong links from many higher brain areas.
Due to links between the breathing and emotion centres, breathing has large effects on our emotions/anxiety and stress.
The links between breathing and emotions is bi-directional as evidenced in panic disorder.