exam 2 lecture 22 Flashcards by jillian Bastidas

The goal of respiration: maintain sufficient ____ with minimal energy

ventilation

How well did you know this?

Not at all

Perfectly

central processor controls ___

•Pattern generator of breathing depth / amplitude

Rhythm generator for breathing rate (periodicity

How well did you know this?

Not at all

Perfectly

three types of sensors to control ventilation

chemoreceptors

baroreceptors

stretch receptors

How well did you know this?

Not at all

Perfectly

where is the central controller?

pon

most in the medulla

How well did you know this?

Not at all

Perfectly

what innervates accessory respiratory muscles?

ventral respiratory group

How well did you know this?

Not at all

Perfectly

what innervates the diaphragm and external intercostal muscles?

dorsal respiratory group

by the phrenic nerve

How well did you know this?

Not at all

Perfectly

respiratory control is a ___ feedback system

neagtive

How well did you know this?

Not at all

Perfectly

what is the hering breuer reflex and what disproves this theory?

taking a breathe triggers a stretch receptor in smooth muscle that triggers another breathe

lung transplant patients disproves this

How well did you know this?

Not at all

Perfectly

•Inspiratory impulses are ___ and are dynamic

dominate

neurons needed to inhale

How well did you know this?

Not at all

Perfectly

during sleep, central drive is ____ so peripheral chemoreceptors stimulate based on O₂ and CO₂ levels

reduced

How well did you know this?

Not at all

Perfectly

why are expiratory neurons not as important

exhale is passive

neurons only needed for forced exhale

How well did you know this?

Not at all

Perfectly

what happens when you cut below the DRG?

breathing stops

phrenic nerve comes off the DRG - no dorsal respiratory group= no breathing

How well did you know this?

Not at all

Perfectly

what happens if you cut off the pons?

breathing with very sharp amplitude

How well did you know this?

Not at all

Perfectly

what happens if you cut off the PRG but keep the apneustic center?

breathing more normal

still high amplitude and slightly slower but more steady

How well did you know this?

Not at all

Perfectly

if you cut above the PRG what happens to breathing?

normal breathing

locked in syndrome

How well did you know this?

Not at all

Perfectly

what is the most important principal initiator of breathing?

dorsal respiratory group

How well did you know this?

Not at all

Perfectly

what part of the DRG receives afferent fibers?

nucleus tractus solaris

•Nucleus tractus solaris is where afferent fibers of the glossopharyngeal and vagus nerves project, carrying information received about PO₂, PCO₂, and pH from the carotid and aortic arterial chemoreceptors

How well did you know this?

Not at all

Perfectly

•Nucleus tractus solaris is where ___ fibers of the glossopharyngeal and vagus nerves project, carrying information received about ___ from the carotid and aortic arterial chemoreceptors.

afferent

PO₂, PCO₂, and pH

How well did you know this?

Not at all

Perfectly

the DRG has outputs via the ___ to the diaphragm, therefor controlling the most important respiratory muscle

phrenic nerve

How well did you know this?

Not at all

Perfectly

what is the most important respiratory group and why?

the dorsal respiratory group (DRG) is responsible for

1) driving the diaphragm
2) receiving/ integrating input from peripheral chemoreceptors.

Therefor it is the MOST IMPORTANT RESPIRATORY GROUP

How well did you know this?

Not at all

Perfectly

what does the ventral respiratory group do?

Connected primarily to vagus nerve
“patency of airway”
Expiratory neurons

How well did you know this?

Not at all

Perfectly

the VRG contains what two specialized groups

Botzinger complex: inhibit inspiratory cells in the DRG
Pre-Botzinger complex: hypothesized (but not proven) to be the precise location of the respiratory rhythm generator

How well did you know this?

Not at all

Perfectly

•Botzinger complex:

•Botzinger complex: inhibit inspiratory cells in the DRG

found in the ventral respiratory group

How well did you know this?

Not at all

Perfectly

•Pre-Botzinger complex

•Pre-Botzinger complex: hypothesized (but not proven) to be the precise location of the respiratory rhythm generator

found in the ventral respiratory group

How well did you know this?

Not at all

Perfectly

what are the two groups found in the pons that control breathing

apneustic center pontine respiratory group

apneustic center

* Apneustic center - nucleus of the pons * Coordinates speed of inhalation and exhalation * Sends **stimulatory** impulses to the inspiratory area – activates and prolongs inhalation (long, deep breaths) * Site of the “inspiratory cutoff switch”

Site of the “inspiratory cutoff switch”

apneustic center in the pons

\_\_\_ coordinates speed of inhalation and exhalation

apneustic center of the pons this is why when you cut this area off, very sharp very long breaths

\_\_\_ sends **stimulatory** impulses to the inspiratory area – activates and prolongs inhalation (long, deep breaths)

apneustic center of the pons

Pontine respiratory group

* Formerly known as the pneumotaxic center * Coordinate speed of inhalation and exhalation * Sends **inhibitory** impulses to the inspiratory area•Involved in fine tuning respiration rate

\_\_\_ Coordinate speed of inhalation and exhalation

pontine respiratory group in the pons

\_\_\_ sends **inhibitory** impulses to the inspiratory area of the DRG

pontine respiratory group of the pons

\_\_\_ involved in fine tuning respiration rate

pontine respiratory group of the pons

•**Cheyne-Stokes respiration**

* Alternating episodes of apnea and crescendo-decrescendo hypernea * Caused by damage to respiratory centers in the brainstem, hypoxia

\_\_\_ •Alternating episodes of apnea and crescendo-decrescendo hypernea

•**Cheyne-Stokes respiration**

•**Apneustic breathing**

* Prolonged inspiration due to interruption of the pneumotaxic center (pontine respiratory group of the pons) * i.e. “dying gasps"- most likely in the pons

•**Biot’s breathing**

* Normal breathing interrupted by sudden apnea * Damage to the pons

biot's breathing

•**Kussmaul’s breathing**

* Hyperventilation with hypocapnia caused by acidosis (diabetic) * Brain is normal, caused entirely by chemoreceptors

•**Kussmaul’s breathing**

•Respiratory center is in the brainstem (medulla \_\_\_)

oblongata

what are two regions of the brain that affect respiration

•**Cortex**•Conscious control of breath•E.g., holding your breath **•****Limbic system and hypothalamus**•Emotional states•Panic attack

how does the body measure changes in CO2

CO2 can diffuse across blood brain barrier combines with H20 and forms H and HCO3- this will decrease the pH of the CSF (make more acidic) this change in pH can be detected by H+ receptors

•**Protons (H⁺) pass poorly through the ___ but CO₂ passes easily**

**blood brain barrier** •**Blood pH is therefor transmitted via CO₂ to CSF**

adapt to elevated CO₂ levels (reduced pH) by transfer of ___ into CSF (slow). this will stimulate \_\_\_

HCO₃^- or Cl^- •Stimulation of this system causes the urge to breath (increase ventilation, **get rid of that CO₂)**

•Recent studies suggest additional chemoreceptors throughout the brainstem:NTS, \_\_\_

locus coeruleus

where is all O2 sensing done to control breathing

carotid and aortic bodies (peripheral chemosensors)

•Afferent nerves (glossopharyngeal for carotid body, vagus for aortic body) run back to the ___ in the medulla to then change the breathing patterns

respiratory center (DRG)

true or false aortic bodies exert greater influence than carotid bodies

false •Carotid bodies exert greater influence than do aortic bodies

\_\_\_ receptors are more important in short-term, transient responses than in normal ventilatory control

carotid body and aortic bodies peripheral chemosensors

how do O2 sensors work

**•****Glomus cells (type I cells)** * K channel with O₂ sensor * O₂ opens channel and hyperpolarizes cell * Drop in O₂ causes reduction in K current and depolarization * Resulting Ca²⁺ influx triggers dopamine release * Dopamine initiates action potential in sensory nerve to send the signal back up to the medula• **Glomus cells are derived from the neural crest****•** **Glomus cells may also be the primary CO₂/ pH chemosensor, but isn’t certain** **Supported by type II cells (sustentacular cells)**

how does low O2 effect glomus cells

causes K channels to close, which causes depolarization and dopamine to be released causing an action potential

what enzyme helps glomus cells to detect oxygen

CSE (cystathione gamma-lyase ) •hypoxia decreases CO production•Less CO means less inhibition of CSE•More active CSE means more H₂S•More H₂S depolarizes cells causing neurotransmitter release

what do cigarette help at high altitude

* PO₂ must drop to 60 mm Hg (~10,000 ft elevation) before this triggers a change in the glomus cells * At these high elevations, PCO₂ is also lower, so fails to increase respiratory drive **(stimulates person to breathe)**

\_\_\_ are much less important than arterial chemoreceptors for ventilation

arterial baroreceptors

•Bronchiolar smooth muscle is enriched in \_\_adrenergic receptors

β₂

•\_\_\_\_ (sympathetic) lead to bronchodilation

Catecholamines

•Parasympathetic stimulation of the muscarinic M₃ receptors (via \_\_\_) causes bronchoconstriction

acetylcholine

catecholamines cause ___ and acetylcholine causes \_\_\_

•bronchodilation (sympathetic innervation) bronchoconstriction (parasympathetic innervation)

what is triggered in an asthma attack to cause bronchoconstriction?

muscarinic M₃ receptors (via acetylcholine- parasympathetic innervation)

•J-receptors

* Sense interstitial fluid changes (pulmonary edema) * Cause sense of breathlessness * Located in capillary walls **breathlessness**

what is the dominant respiratory driver?

CO2