Respiratory System

Question 0

Structure

Answer 0

• like upside down tree–>trachea trunk, bronchi branches
• tube with many branches
• ends in millions of tiny, thin-walled sacs (alveoli)
  
  • distribute air close enough to blood
  • through diffusion
• upper resp. tract
  
  • nose, pharynx, larynx
  • head cold
• lower resp. tract
  
  • trachea, bronchial tree, lungs
  • chest cold

Question 1

Function

Answer 1

• distribute air
• exchange gas
  
  • supplies oxygen
  • removes CO2
• maintain constant environment
• filters, warms, humidifies air we breathe
• influences speech and sound production

Question 2

Respiratory Mucosa

Answer 2

• specialized membrane lining air distribution tubes
• mucus traps irritants and purifies air
• mucociliary elevator
  
  • cilia beat in one direction
  • move mucus towards pharynx for removal
• mucus
  
  • 125ml produced daily
  • forms mucous blanket
• pseudostratified columnar epithelium

Question 3

Nose

Answer 3

• external nares-nostrils
• nasal septum–>separates R&L nasal cavities
• olfactory receptors located in nasal mucosa
• paranasal sinuses–>spaces lined with mucus
• lacrimal sacs–>collect tears from corner of each eyelid
• conchae–>shelf-like structures, increase SA
• function
  
  • drains mucus
  • warms and humidifies air as it passes
  • mucous membrane traps irritants

Question 4

Pharynx

Answer 4

• ‘throat’, 12.5cm
• Nasopharynx
  
  • uppermost, behind nasal cavities, pharyngeal
  • Eustachian tubes connect to middle ear
    
    • permits equalization of air pressure
• Oropharynx
  
  • portion behind mouth, palatine tonsils
• Laryngopharynx
  
  • lowest segment
• air and food pass through on way to lungs and stomach

Question 5

Larynx

Answer 5

• aka voice box, just below pharynx
• composed of pieces of cartilage
• vocal cords
  
  • 2 short fibrous bands
  • stretch across interior of larynx
  • tense=high, relaxed=low
• glottis–>space between vocal cords
• epiglottis
  
  • cartilage
  • partially covers opening of larynx
  • prevents food from entering trachea

Question 6

Trachea

Answer 6

-aka windpipe, 11cm, from larynx to bronchi
-lined with resp. mucosa–>part of blanket of mucus
-15 or 20 C-shaped rings of cartilage with soft tissue between
-obstruction
-air has no other way to lungs
-complete obstruction can cause death within minutes
Function
-air distribution, passageway
-protective
-production and movement of mucus
-traps and eliminates contaminants

Question 7

Bronchi and Bronchioles

Answer 7

Bronchi

• rings of cartilage
• primary bronchi
  
  • trachea’s 1st branches
  • R&L bronchus
• secondary bronchi
  
  • smaller branches in each lung

Bronchioles

• tiny tubes, branches of secondary bronchi
• contain only smooth muscles
• alveolar ducts
  
  • microscopic subdivisions of bronchioles
• alveolar sacs
  
  • terminal ends of alveolar ducts

Question 8

Alveoli

Answer 8

• make up alveolar sac
• rapid and effective gas exchange (b/w blood and air)
• millions, increase SA

Respiratory Membrane

• separates air from blood
• surfactant
  
  • substance covering respiratory membrane
  • reduces surface tension
  • keeps alveoli from collapsing

Question 9

Lungs

Answer 9

• R has 3 lobes, L has 2
• apex is narrow, superior portion of lungs
• base is inferior portion
• pneumothorax
  
  • presence of air in intrapleural space
  • increased pressure, causes it to collapse

Question 10

Pleura

Answer 10

• covers outer surface of lungs
• lines inner surface of rib cage
• extensive, thin, moist slippery membrane
• parietal pleura lines walls of thoracic cavity
• visceral pleura covers lungs
• intrapleural space between 2 pleural membranes

Question 11

Respiration

Answer 11

• exchange of gases b/w a living organism and environment
• pulmonary ventilation (aka breathing)
• external resp. (b/w air in lungs and blood)
• int. resp. (b/w blood and cells)
• cellular resp. (use of O2 by cells in metabolism)
• difference of air pressure causes movement of air into/out of lungs

Question 12

Inspiration

Answer 12

• inhalation, moves air into lungs
• chest cavity enlarges
• contraction increases volume of thoracic cavity and decreases air pressure within drawing of air into lungs

Inspiratory muscles

• diaphragm
  
  • flattens when contracts
  • makes chest cavity longer
  • stimulated to contract by phrenic nerve
• external intercostals
  
  • increase cavity size front/back, side/side

Question 13

Expiration

Answer 13

• exhalation, moves air out of lungs
• chest cavity returns to smaller size
• inspiratory muscles relax
• as cavity decreases in size, air pressure increases and air flows out of lungs

Expiratory Muscles

• interior intercostals
  
  • depress rib case and decrease front/back size
• ab muscles
  
  • push against diaphragm, which becomes dome-shaped again

Question 14

External Respiration

Answer 14

• exchange of gases in lungs (b/w blood and alveolar air)
• occurs by diffusion
• pressure (concentration of a gas in air or w/in blood)
• concentration of resp. gases (partial pressure P)
• movement of O2
  
  • high pressure (alveolar air) to area of low pressure (pul. cap.)
• movement of CO2
  
  • high pressure (pul. cap.) to low pressure (alveolar air)

Question 15

Internal Respiration

Answer 15

• exchange of gases in tissues between blood and cells
• O2
  
  • out of blood, into interstitial, into cells
  • high (systemic capillaries) to low (cells)
• CO2
  
  • leaves cells, through interstitial, to systemic cap.
  • transported to lungs
  • high (cells) to low (systemic cap.)

Question 16

Transport of Oxygen

Answer 16

-limited amounts dissolved in blood (1.5%, 0.3mL)

Oxyhemoglobin

• O2 combined with Hb
• contains 4 iron-containing heme components, each combines w/ O2
• combination reversible

Question 17

Transport of CO2

Answer 17

• dissolved in blood (10%)
• carbaminohemoglobin (20%)
  
  • union of CO2, Hb, other plasma proteins
• Bicarbonate Ions (HCO3) (70%)
  
  • Co2 w/ water becomes H2CO3 (carbonic acid)
  • some dissociate to form H and HCO3
  • process slow in plasma
  • faster in RBCs (carbonic amylase)
  • reaction reversible

Question 18

Air Volumes

Answer 18

Tidal Volume (TV)

• amount of each normal breath
• about 500mL

Vital Capacity (VC)

• largest amount breathe out in one expiration
• VC=TV+IRV+ERV

Expiratory Reserve Volume (ERV)
-amount of air forcibly exhaled after expiring tidal volume

Inspiratory Reserve Volume (IRV)
-amount of air forcibly inspired over and above normal inspiration

Residual Volume (RV)
-air remaining in lungs after most forceful expiration

Question 19

Regulation of Respiration

Answer 19

Cerebral Cortex

• modifies rate at which neurons ‘fire’ in insp/exp. centers of medulla
• voluntarily speed up/slow down rate and pattern

Chemoreflexes

• chemoreceptors in carotid and aortic bodies
• sensitive to increase in blood CO2 level and decrease in O2 level
• send nerve impulse to regulatory centers

Pulmonary Stretch Reflexes

• influence normal breathing pattern
• protect system from excess stretching by overinflation
• lungs deflated to inhibit receptors

Question 20

Types of Breathing

Answer 20

Eupnea-normal
Hyperventilation-rapid and deep resp.
Hypoventilation-slow and shallow resp.
Dyspnea-difficulty breathing
Apnea-stops completely for short periods
Resp. Arrest-failure to resume breathing after prolonged apnea