BMS respiratory system

The main function of the respiratory system?

The main function of the respiratory system?

gas exchange across an epithelium

What happens during gas exchange?

- O2 moving from air into blood
- O2 attaching to Fe on hemoglobin
- CO2 moving from blood to air

What is the respiratory zone?

- site of gas exchange
- alveolar epithelium meets the endothelium of pulmonary capillaries

What is the conducting zone?

- series of tubes to deliver air to the respiratory zone
- highly branched

What makes up the conducting zone?

- pharynx
- larynx (vocal cords)
- trachea
- hyaline cartilage rings
- bronchus
- bronchi
- bronchioles
- smooth muscle wrapped around bronchi

What makes up the respiratory zone?

- terminal bronchi
- alveolus

What is the alveolus and what is its function?

- single layer of epithelial cells
- site of gas exchange

Where are mast cells located?

adjacent to the epithelial cells in the tubes of conducting cells

What are the two different elements that can cause smooth muscle contraction?

- GPCR
- histamine

What are the two different elements that can cause smooth muscle relaxation?

- B2 adrenergic receptor (GPCR)
- epinephrine

What is IGE?

- immunoglobulonase
- TMP

How does asthma happen?

- antigen binds to mast cells/IGE
- mast cells/IGE release histamine
- causes smooth muscle contraction
- shuts off air flow through the tubular system

What happens during parasympathetic innervation of the bronchiolar smooth muscle?

- muscarinic receptors cause smooth muscle contraction
- no sympathetic innervation--causes B2 receptors to bind epinephrine and releasing a hormone from the adrenal medulla

What is the story of the epi pen and peanut allergies?

- breathes in air with peanut electin
- peanut electin binds to IGE which releases histamine
- smooth muscle constricts
- shuts down radii of the bronchioles
- stops breathing
- stick epi pen in thigh
- increase epinephrine
- increase blood pressure because of the alpha 1 receptors
- increase heart rate because B1 receptors
- epinephrine binds to B2 GPCR
- smooth muscle relaxes
- increase radii of bronchi
- decrease resistance to flow

What is the sympathetic response?

- release epinephrine
- relax smooth muscle
- reduce resistance to get air in alveolar spaces
- emergency situations

What zone does gas exchange occur in?

RESPIRATORY ZONE

What zone delivers gas?

CONDUCTING ZONE

Does parasympathetic constrict the smooth muscle at all?

- yes, only a little
- doesn't want to consume so much of the volume of the respiratory tract in conducting zones
- alveolar region is now larger in proportion to the conducting zone
- decrease area of the conducting zone
- increase area of alveoli for gas exchange

What is a Type I Pneumocyte?

layer of alveolar epithelial cells that makes up the respiratory zone

What is a Type II Pneumocyte?

Secretes surfactant

What is surfactant?

- phosphytidyl choline

What does surfactant do?

breaks up the surface tension of water molecules in alveolar sac

What is the function of surfactant?

allows the air to get into the lungs easily

How does diffusion happen?

- diffuses through the fluid build up in the alveolus
- through the PLB of Type I Pneumocytes
- through the cytoplasm
- out the other side
- through to the O2 poor erythrocytes

What makes up the pulmonary capillary?

single layer of endothelial cells

What happens when the fluid in the alveolus gets really thick?

- increases diffusion path
- O2 can't get through the air sac to the erythrocytes

What is the problem with the fluid in the alveolar sac?

fluid doesn't allow the sac walls to open very much

What is the problem with pre-me's?

-after being in the womb, babies need to learn to breathe on their own
- pre-me's don't have activated Type II Pneumocytes
- lacking adequate surfactant
- babies can't breathe well because air isn't getting into the lungs
- this is due to the alveoli being stuck together because of the high surface tension

How is surface tension decreased?

- separate dipole moments
- caused by phosphytidyl choline

What is the visceral pleura?

set of mesothelial cells attached to the wall of the lungs

What is the parietal pleura?

Set of mesothelial cells on the other side of the intrapleural space

What is the intrapleural space?

- without it, there would be friction and pain
- always at a negative pressure with respect to atmosphere and inside of the lung

What is the elastic lung?

- it contracts itself

What happens when there's a hole in the body wall?

- goes into the pleural sac
- doctors have to cover hole
- remake the pressure vacuum
- reinflates the lung

What is the diaphragm?

skeletal muscle innervated by lower motor neurons

What happens when there is low pressure in the lungs?

takes air in

What happens when there is high pressure in the lungs?

pushes air out

What happens to the diaphragm during muscle contraction?

diaphragm deflates/flattens

What happens to the diaphragm during muscle relaxation?

- diaphragm pops back up
- due to elastic recoil snapping

Correlation between contracting diaphragm and volume of the thoracic cavity?

- contracting diaphragm increases volume of thoracic cavity
- diaphragm volume decreases = thoracic cavity volume increases

What is the function of elastic recoil?

- returns diaphragm to original length
- resets lung volume

What happenns with emphysema?

- damage to lung
- breaks down elastin
- size of alveoli gets bigger (the walls move apart)
- bad surface tension
- breathe in fine
- no elastic recoil/hard to breathe out

What is compliance?

ease of filling the lungs

What is elastic recoil?

ability of lung elasticity to permit air to be exhaled

What happens to compliance and elastic recoil in emphysema?

- increase in lung compliance
- decrease in elastic recoil
- breathe in fine, can't breathe out

What happens to compliance and elastic recoil in fibrotic diseases?

- increase in elastic recoil
- decrease in compliance
- can't breath in, breathes out fine

What is the O2/N2 % in air

- 21% O2
- 79% N2

What is the difference in partial pressures in sea level vs. FoCo?

760 mm Hg vs. 640 mm Hg

Is [O2] higher in the blood or the alveolus?

[O2] alveolar > [O2] blood

Is [CO2] higher in the blood or the alveolus?

[CO2] alveolar < [CO2] blood

What are the percentages of CO2, O2, N2, and H2O in the air sac?

- CO2 = 5.2%
- O2 = 13.7%
- N2 = 74.9%
- H2O = 6.5%

What are the pressures of CO2 and O2 oxygenated/deoxy in the blood stream and in the air sac?

Air sac
- CO2 40 mm Hg
- O2 106 mm Hg
Deoxy blood
- CO2 45 mm Hg
- O2 40 mm Hg
Oxy blood
- CO2 40 mm Hg
- O2 45 mm Hg

Why does hyperventilation occur?

decrease in [CO2]

What is Henry's Law?

gases go into solution in H2O in proportion to their partial pressures

What does this graph imply about binding and hemoglobin?

- with each binding of O2 to hemoglobin, the probability increases of binding
- explains why diffusion is so fast

What is the hill coefficient?

- the slope
- it's always 4 because there's 4 binding sites on the hemoglobin for O2

What does the right shift mean?

- warmer temperature
- decreased O2 attached to hemoglobin
- low pH

What does the left shift mean?

- colder temperature
- increased O2 attached to hemoglobin
- high pH

What kind of blood does the PO2 dissociation curve look at?

venous blood

What is the bohr effect?

- rightward shift results from low pH (H+ effect)
- binding of H+ to hemoglobin that reduces O2 affinity

How much CO2 in the blood is carried as HCO3-?

70-75%

What does carbonic anhydrase do?

- enzyme that speeds up the reaction
CO2 + H2O => H+ + HCO3-
- increases it million fold

What does H+ do in the cerebrospinal fluid?

- signal to sensory neurons in the brain stem
- drives LMN in cervical spinal cord
- drives diaphragm

Which part of the respiratory system is lined with both stratified squamous and pseudostratified columnar epithelium

pharynx

The mucociliary clearance is accomplished by? (epithelium lining the respiratory tract)

ciliated pseudostratified columnar

an infection in the (bronchi + trachea) would indicate which part of the respiratory system is affected?

lower

Forced air expiration out of the lungs

contraction of abdominal muscles

contraction of diaphragm / intercostal muscles

move air in

The chloride shift will

aid in transportation of bicarbonate in blood plasma

the intrapulmonary pressure is greater than atmospheric pressure during?

expiration

parts if the conduction zone (portion)

nares/ mouth, pharynx, larynx, trachea,

(nasal cavity to larger bronchioles)

Respiratory portion

bronchioles + alveoli

type 2 pneumocytes

produce surfactant, reduces surface tension in alveoli to keep them open

type 1 pneumocytes

gas diffusion

upper division respiratory system

nose, nasal cavity, pharynx

lower division respiratory system

larynx, trachea, bronchus, bronchioles, lungs, alveoli

Conducting portion

Respiratory track to larger bronchioles

purpose of conducting portion

prepare are “filtration”

Respiration portion

smallest respiratory bronchioles + alveoli

purpose of respiratory portion

gas exchange

Where is simple squamous epithelium found in the respiratory system

alveoli

Cuboidal Epithelium - scattered cilia

smaller bronchioles

Stratified Squamous epithelium

Inferior portions of the pharynx (protective function)

Pseudostratified - ciliated columnar epithelium with numerous mucus cells

Nasal cavity, superior portion of pharynx, superior portion of lower respiratory system