KNES 191A FINAL exam

Functions of the respiratory system (6)

1. Respiration: gas exchange between atmosphere and cells

2. moving air to and from the exchange surfaces of the lungs

3. pH regulation

4. Protection

5. Producing sounds

6. Facilitating the detection of stimuli

4 events of respiratory system

1. Movement of air in and out of the lungs - breathing or

pulmonary ventilation.

2. Gas exchange (diffusion) between the lungs and the blood.

3. Gas transport in blood between the lungs and body cells.

4. Gas exchange (diffusion) between blood and body cells.

upper respiratory tract (outside thorax)(4)

Nose

Nasal cavity

Sinuses

Pharynx

lower repiratory tract (inside thorax) (4)

Larynx

Trachea

bronchial tree

Lungs

function of upper respiratory tract

Passageways filter, warm, and humidify incoming air - protecting the more delicate surfaces of the lower respiratory system- and cool and dehumidify outgoing air.

Nose

Internal nostril hairs - act as a filtering system preventing entry of large particles carried in the air.

Nasal Cavity

The nasal cavity is the hollow space behind the nose; lined with mucous membrane and blood vessels. heats the air coming in through the nose.

Cilia

microscopic hair-like structures of the epithelial lining. Form in precise patterns and wave in a coordinated back and forth manner to push down mucus and entrapped particles to the pharynx

Paranasal sinuses

Air-filled spaces located within certain bones of the skull that open to the nasal cavity. The paranasal sinuses decrease the weight of the skull and are resonant chambers that affect the quality of the voice.

Pharynx

Located behind the oral cavity; between the nasal cavity and the larynx. Provides a passageway for food traveling from the oral cavity (mouth) to the esophagus (leads to stomach) and for air passing between the nasal cavity and larynx. Pharynx also helps produce the sounds for speech. Houses the tonsils.

larynx

houses the vocal cords. conducts air in and out of the trachea through a narrow opening called the glottis.

laryngeal prominence

adams apple. located in the larynx and is part of the framework of muscles and cartilages bound by elastic tissue.

Epiglottis

a laryngeal cartilage, is a flap-like structure that allows air to enter the larynx. The epiglottis projects superior to the glottis and forms a lid over it. When swallowing, the larynx is elevated bending the epiglottis over the glottis partially covering the larynx so that the bolus of food chewed can glide across the epiglottis rather than dropping into the larynx. The epiglottis serves to seal off the respiratory tract when food or liquid passes into the esophagus. During normal breathing, the epiglottis is relaxed (upright).

how does coughing occur?

Food or liquids that get too close to the entrance of the glottis trigger the coughing reflex. In a cough, the glottis is kept closed while the chest and abdominal muscles contract, compressing the lungs. When the glottis is opened suddenly, the resulting blast of air from the trachea ejects material that blocks the entrance to the glottis.

true vocal cords (vocal folds)

Sound is made by air forced through the glottis between the true vocal cords (vocal folds) causing them to vibrate from side to side, generating sound waves.

phonation

the sound waves produced by true vocal cords

articulation

Words that are made up by altering the shapes of the pharynx and oral cavity using the tongue and lips

False vocal cords (ventricular folds)

muscles responsible for controlling tension in the vocal folds and sealing of the glottis during swallowing.

Trachea

flexible tube extending down anterior the esophagus and into the thoracic cavity, where it splits into left and right bronchi.

brachial tree

Consists of branched airways leading from the trachea to the microscopic air sacs (alveoli) in the lungs.

sympatheric activation vs parasympathetic activation

sympathetic: brachiodilation

Parasympathetic: Brachioconstriction

Lungs

oft, spongy, cone-shaped organs in the thoracic cavity. Each lung occupies the majority of the thoracic space on its side

Right lung vs left lung

right: has 3 lobes

left: has 2 lobes

pleural membrane

Each lung is enclosed and protected by a double-layered serious membrane

walls of pleural membrane

-visceral pleura - attached to each lung surface and folds back to become the parietal pleura. The pleurae form a double walled sac,

space in between the walls of the pleural membrance

pleural cavity. The pleural cavity contains a thin film of serous fluid referred to as pleural fluid

purpose of venthilation

to prevent the build up of carbon dioxide in the alveoli and ensure a continuous supply of oxygen that keeps pace with absorption by the bloodstream.

Normal inspiration

Nerves stimulate the diaphram to contract. As it contracts, the diaphragm moves downward, the thoracic cavity enlarges, and the pressure within the alveoli falls slightly below that of atmospheric pressure. In response, atmospheric pressure forces air into the airways.

atmospheric pressure at sea level

760 mm Hg

what is responsible for the air movement in normal at rest breathing

Diaphram- 75%

External intercostal muscles- 25%

what muscles are involved in deep breath?

ectoralis minor, scalenes, serratus anterior and sternocleidomastoid muscles.

what holds the visceral and parietal pleural together?

Surface tension

As elevation increases...

P02 decreases in the atmospheric air and in the alveoli resulting in less rapid diffusion of oxygen from the alveoli into the blood (decreased saturation of hemoglobin with oxygen)

Percentage of O2 stays the same ~21%

Tidal volume

the volume of air that enters (or leaves) during a single respiratory cycle under resting conditions and during a normal breath.

inspiration reserve volume

The maximal amount of air that can be taken into the lungs by determined effort after normal inspiration. Normal to maximum capacity

expiratory reserve volume

Amount of air that can be forcefully exhaled after a normal tidal volume exhalation

residual volume

Amount of air remaining in the lungs after a forced exhalation

Vital capacity

The largest volume of air that a person can exhale after taking the deepest breath possible.

Inspiratory capacity

the maximum volume of air a person can inhale following a resting inspiration

Functional residual capacity

the volume of air that remains in the lungs following a resting expiration.

Total lung capacity

vital capacity plus the residual volume

The maximal volume of air that the lungs can contain.

VO2 Max

the greatest amount of oxygen that the body can take in, transport, and utilize during heavy exercise.

ordinary air percentages

78% nitrogen 21% oxygen

.04% carbon dioxide .5% water

oxygen after it diffuses into the blood stream

98% of the oxygen diffuses in the blood and binds to hemoglobin forming Oxyhemoglobin. the remainder dissolves in the plasma

hemoglobin saturation

percentage of heme units containing oxygen

3 ways CO2 is transferred in the body

1. as carbon dioxide dissolved in plasma (~7%), or

2. as part of a compound formed by bonding to hemoglobin

(~23%), or

3. as part of a bicarbonate ion (~70%).

bicarbonate ion transfer

CO2 combines with water to make carbonic acid (H2CO3). The hydrogen in carbonic acid quickly combine with hemoglobin making the carbonic acid turn into bicarbonate ion (HCO3-).

local regulation

The rate of oxygen delivery in each tissue and the efficiency of oxygen pickup at the lungs

as metabolic activity increases...

PO2 decrease and CO2 increase

lung perfusion

blood flow to lungs

Alveolar ventilation

Airflow into aveoli

Ventral (Inspiratory) respiratory group (VRG)

responsible for the basic rhythm of breathing; emit bursts of impulses that signal the diaphragm and the external intercostal muscles to contract.

basic rhythm of breathing

Starts an impulse weakly then strengthens abruptly for 2 seconds. then stops for exhalation ~3 seconds

Dorsal ( Expiratory) respiratory group (DRG)

quiet during normal breathing. DRG neurons generate impulses when more forceful breathing is required. If VRG activity increases, neurons of the DRG are stimulated resulting in the activation of inhalation accessory muscles, such as SCM, pectoralis minor, and the scalenes.

Pontine impulse Strong vs Weak

When pontine impulses are strong (output quickens) - the effect is inhibitory, that is, the inspiratory bursts are shorter and breathing rate increases; when signals are weak (output slows), the inspiratory bursts are longer, and the breathing rate decreases.

chemoreceptor reflexes

Monitor changes in arterial PCO2, PO2, and ph. Located in the respiratory center of the medulla.

peripheral chemoreceptors(location and action)

Located in the Coratid and aortic arteries. Monitors when the levels of oxygen are really low or a decrease in blood pH, or a rise in CO2

Central Chemoreceptors (location and action)

Located in the respiratory center of the medulla and monitor when the levels of CO2 and hydrogen are elevated

what is more sensitive receptors for O2 or CO2?

Chemoreceptors monitoring carbon dioxide are much more sensitive than those monitoring oxygen.

baroreceptor reflexes(location and action)

Stretch receptors in the coratid and aortic arteries that affect respiratory activity.

relationship between blood pressure and breathing (baroreceptors)

When blood pressure falls, the respiratory rate increases; when blood pressure rises, the respiratory rate declines.

hering-breuer Reflex Inflation (location and action)

Occurs in the visceral pleura, alveoli, and bronchioles. helps regulate the depth of breathing and prevents over inflation during forceful breathing.

Hering-breuer Reflex deflation (location and action)

located in the alveolar wall and inhibits the expiratory centers and stimulates the inspiratory centers.

Hering-Breuer Protective reflexes (location and action)

Located in the Epithylum Operate when exposed to toxic vapors, chemical irritants, or mechanical stimulation in the respiratory tract

types of protective reflexes

sneezing, coughing, and laryngeal spasms

laryngeal spasms

sealing off of the glottis as a result of iritants

cortical Influence

The activity of respiratory center and chemoreceptors can be voluntary by being overridden by the cerebral cortex.

how is conscious control possible?

respiratory muscles are voluntary muscles.

respiratory compliance

the amount of change in lung volume produced by a change in pressure

respiratory compliance with age

decrease in elastic tissue, decrease in costal cartilage felxibility, increase in emphysema all contribute to a lower compliance with age.