A & P (1) - Respiratory System, Regulation Of Respiration

Front 1

Which area of the brain is responsible for setting the normal baseline respiratory rate?

Back 1

Inspiratory area of the medullary rhythmicity centre

Front 2

Describe how neural activity in the medulla oblongata leads to a 2 second inspiration followed by a 3 second expiration?

Back 2

Neurons within inspiratory area of medullary rhythmicity centre fire for 2 seconds, impulses carried to intercostal nerves and phrenic nerve, external intercostals and diaphragm contract for 2 seconds. Nerve impulses cease and allow the muscles to relax for three seconds and the elastic recoil of the lungs causes expiration

Front 3

What is the function of the pneumotaxic area and where is it located?

Back 3

Helps coordinate breathing. Transmits inhibitory impulses to the inspiratory area of the medullary rhythmicity centre. When the pneumotaxic area is active, these impulses shorten the duration of inhalation.

In other words, impulses from the pneumotaxic area "switch off" the inspiratory area, allowing expiration to occur

Located in the pons

Front 4

What is the function of the the apneustic area? Where is it located?

Back 4

Activates the inspiratory area of the medullary rhythmicity centre, prolonging inspiration

Located in lower pons

Front 5

What three areas constitute the respiratory centre?

Back 5

1) Medullary rhythmicity centre (medulla)

2) Pneumotaxic area (pons)

3) Apneustic area (lower pons)

Front 6

What nerve carries impulses from the carotid body chemoreceptors?

Back 6

CN IX - glossopharyngeal nerve

Front 7

Branches of which nerve carry impulses from the aortic body body chemoreceptors?

This question needs to be more specific.

Back 7

CN X - vagus nerve

Front 8

What are the carotid bodies?

Back 8

The carotid bodies are clusters of chemoreceptors located in the internal and external carotid arteries just distal to the division of the common carotid artery.

They sense PCO2 and especially PO2 in arterial blood and provide input to the respiratory centre/generator in the medulla via the glossopharyngeal nerve (CN IX).

Front 9

What is hypercapnia? What is another name for hypercapnia?

Back 9

Elevated levels of the partial pressure of carbon dioxide in arterial blood, also called hypercarbia

Front 10

What sets of chemoreceptors input to the respiratory centre and where are they located?

Back 10

1) Central chemoreceptors - located near the medulla oblongata and sense the content of the CSF

2) Peripheral chemoreceptors
-Aortic bodies (aortic arch)
-Carotid bodies (point where common carotid divides)

Front 11

What is hypoxia?

Back 11

Deficiency of oxygen at the level of the tissues

In other words, it's when the tissues don't have enough oxygen, for any reason.

Front 12

What effect does hypocapnia/hypocarbia have on central/peripheral chemoreceptors and the rate/depth of breathing?

Back 12

None

Front 13

What's an Ondine and what is Ondine's curse?

Back 13

An Ondine (Undine) is a type of water nymph from mythology and alchemy. Legend has it that one particular Undine cursed her unfaithful husband, causing him to lose autonomic control of breathing while sleeping (Wikipedia)

Ondine's curse is a rare congenital condition in which autonomic control of breathing is disturbed but normal cerebral (voluntary) control over breathing is intact

Front 14

What two disturbances in blood gas can trigger a response by the chemoreceptors and respiratory generator?

Back 14

1) Hypercapnia (increased arterial partial pressure of carbon dioxide > 40 mmHg)

2) Hypoxia/hypoxemia (decreased partial pressure of oxygen <100 mmHg)

Front 15

The central chemoreceptor is most sensitive to changes in what blood gas?

Back 15

Carbon dioxide (PCO2 and, by extension, H+)

Front 16

The peripheral chemoreceptors (aortic bodies and carotid bodies) are most sensitive to what blood gas disturbance?

Back 16

Hypoxia (PO2 less than 100)

Front 17

What homeostatic variables does the respiratory system help maintain?

Back 17

Levels of arterial blood gases (PCO2 around 40 and PO2 around 100)

Front 18

What response does chronic hypercapnia have on the ventilatory response to chemoreceptors?

Back 18

Blunts the normal response of increased rate and depth of breathing.

Front 19

What two proximate variables can the respiratory centre/generator alter? What is the ultimate reason these variables are altered?

Back 19

Rate and depth of breathing are altered to maintain arterial levels of PCO2 and PO2

Front 20

What is the primary drive to breathe?

Back 20

Climbing levels of arterial PCO2 are the strongest factor leading you to take a breath. Without hypercapnia your drive to breath is severely diminished

Front 21

At what partial pressure of oxygen does hypoxia become the primary drive to breath?

Back 21

PO2 always contributes a little, but doesn't really take the reins until it drops below 60 mmHg (normal = 100 mmHg)

Front 22

Name three factors, other than PCO2/pH and PO2 that can effect respiratory rate:

Back 22

Limbic system stimulation (emotion)

Pain

Stretching of anal sphincter muscle

Front 23

What effect does pain have on respiratory rate?

Back 23

Sudden severe pain may cause apnea,

Front 24

What effect does body temperature have on respiratory rate?

Back 24

Increasing temperature increases resp. rate

A sudden cold stimulus causes apnea

Front 25

Name a bizarre technique for stimulating respiration in a newborn baby or a person who has stopped breathing.

Back 25

Stretching the anal sphincter muscle