Shared Flashcard Set

Details

125 Lecture 10
The Autonomic control of breathing
32
Anatomy
Undergraduate 1
05/14/2013

Additional Anatomy Flashcards

 


 

Cards

Term

true or false?

breathing is controlled automatically but can be voluntarily suspended or altered for short periods of time

Definition

this is true.

 

Automatic breathing can remain in 'brain dead' individuals who have lost brain cortical function

Term
which disease is a rare genetic condition in which the patient stops breathing when asleep?
Definition

Ondine's curse

 

named after the myth of Ondine who cursed her unfaithful lover so that if he fell asleep he would forget to breathe, eventually he fell alseep from sheer exhaustion and his breathing stopped!

Term
what type of disorder is Ondine's curse?
Definition

it is a respiratory disorder. It is fatal if left untreated.

 

Failure of autonomic breathing leads to >CO2 and <O2 in the blood.

 

this disorder can also result from spinal or brain trauma. person's affected suffer from respiratory arrest during sleep but apnea can also occur when awake.

Term
what is apnea?
Definition
it is th sessation of breathing
Term
a mutation on which genes causes Ondine's curse?
Definition

mutation in PHOX2B gene on Chromosome 4

 

this gene codes for a transcription factor needed for development of neuronal pathways involved in autonomic control of breathing

Term
`which part of the brain initiates breathing patterns that have emotional connotations eg. gasps, sighs, laughs?
Definition
the forebrain
Term
which part of the brain issues modifications to breathing for purpose of speech and volitional control?
Definition

motor cortex

 

Term

which part of the brain participates in breathing modulations associated with postural changes?

Definition
Cerebellum
Term

true or false?

Levels of CO2 regulate breathing more than levels of O2?

Definition

True.

 

 

Both the rate and depth of breathing are regulated so that PCO2 in arterial blood is kept close to 40mm Hg

this can be overridden when arterial oxygen tension drops below 60 mm Hg. This is only likely in high altitudes or lung disorders

Term
define respiratory rate
Definition
No of breaths per minute
Term
how is minute respiration volume (MRV) or minute ventilation calculated?
Definition

respiratory rate x tidal voume = MRV

 

MRV = 5 litres per minute but can raise to 130 litres/minute

Term
co2 levels have a much more pronounced effect on the rate of breathing than O2 levels unless the Po2 falls below which level?
Definition

60 mm Hg. This is dangerous!

 

 

the normal resting level of arterial Po2 is 100 mm Hg

the normal resting level of arterial Pco2 is 40 mm Hg

Term

if someone had Pco2 of >90mm Hg what would this result in?

 

 

if someone had pCO2 of >180 mm Hg what would this result in?

Definition

pCO2> 90 mm Hg = coma

 

pCO2> 180 mm Hg = death

Term

which controller initiates each breath? where is it located?

 

which sensors report back to the central controller?

Definition

a central respiratory controller initiates each breath

 

it is located in the brainstem (medulla oblongata) at the base of the brain.

Term
what do sensors and their afferents provide?
Definition
information on the current state of the system
Term
what does the central controller do?
Definition
it co-ordinates an appropiate response to restore the system to normality (homeostatis)
Term
what do efferents and effectors do?
Definition
they provide output to bring about the action required eg. control of muscles
Term
which stretch receptors monitor lung volume?
Definition

proprioceptors

 

these are found in lungs and in respiratory muscles. they cause the inhibition of inspiration and promotion of expiration upon lung inflation

Term
name the 2 sets of chemoreceptors
Definition

Central Chemoreceptors - responsive to arterial pCO2 by monitoring acidity of the cerebrospinal fluid (CSF) that bathes the brain and spinal cord

 

Peripheral Chemoreceptors - responsive to arterial pCO2, pO2 and H+ concentration

Term

where are the central chemoreceptors located?

 

how are medullary chemoreceptors stimulated?

Definition

on the ventral surface of medulla oblongata in the brain stem.

 

these chemosensitive cells are bathed in CSF that has an equilibrium with arterial pCO2. CSF CO2 combines with water to form carbonic acid which dissociates into H+ ions and bicarbonate.

 

The CSF H+ ions diffuse into the tissue to stimulate medullary chemoreceptors

Term
the ventral surface of the medulla oblongata where the central chemoreceptors are located contains how many CO2 (H+) sensitive areas?
Definition
3 co2(H+) sensitive areas
Term
where are the peripheral chemoreceptors located?
Definition

in the carotid bodies of carotid arteries. These branch from the aorta

 

also located in the aortic bodies in the aorta itself.

 

 

Term
which receptors in the carotid arteries and aorta detect changes in blood pressure?
Definition
baroreceptors
Term
which part of the brain can alter the output response generated by the main respiratory controller?
Definition

the Pons

 

 

extra: the medulla has the primary centres responsible for generation of respiratory rhythm.

Term
when.........pCO2 increases and pO2 decreses there is a ........ in blood pH and pO2 and an increase in blood pCO2. this is fed back by .......... chemoreceptors (carotid bodies and ....... bodies) to the brain stem respiratory centre which will make a decsion on how to return the symtem to ...........
Definition
blood, decrease, peripheral, aortic, homeostasis
Term
when there is an > in blood pCO2 and a decrease in blood pO2 what happens to the pH of the CSF?
Definition
it decreases and becomes more acidic. this is fed back by central chemoreceptors in the medulla oblongata of the brain to the brain stem respiratory centre which acts to ensure homeostasis
Term
what are irritant receptors? where are they located?
Definition

these receptors respond to mechanical or chemical irritation and elicit complex reflexes such as sneezes and coughs

 

they are located throughout airways and lungs

Term
which receptors measure mean arterial pressure? where are they located?
Definition

baroreceptors located in the aorta and carotid arteries measure mean arterial pressure.

 

 

Term
with regards to the autonomic input from the medulla which nerve transmits impulses to decrease cardiac output?
Definition
the Vagus nerve - parasympathetic. the transmission goes to the SA Node and the AV Node
Term
with regards to the autonomic input from the medulla which nerve transmits impulses to increase cardiac output?
Definition
the sympathetic cardiac nerve stimulates cardiac output. the signal is transmitted to the SA Node, AV Node and to the ventricular myocardium
Supporting users have an ad free experience!