Chapter 22- Respiratory system

Physical Factors effecting ventilation

Ventilation is dependent on the contraction and relaxation of the muscles of the diaphragm and the thorax (intercoastal muscles). During inspiration -the ribs are elevated -diaphragm is depressed increasing the volume of the thoracic cavity because the lungs are held to the thoracic cavity via the pleurae, the lungs expand with the thoracic cavity

VC

Vital Capacity (VC) = TV + IRV + ERV

Patm

atmospheric pressure: the pressure exerted on an object from its surrounding. Other pressure values in the body are in reference to the atmospheric pressure

What is are the mechanisms that drive breathing?

inspiration and expiration are dependent on a difference in pressure between the atmosphere and lungs. **Gas ALWAYS flows from high pressure to low pressure**

Pip

intrapleural pressure: the pressure inside the pleural cavity, between the visceral and parietal layer. Always lower than Patm and Palv.

IC

Inspiratory Capacity (IC) = IRV + TV

What is the difference between internal and external respiration?

Internal respiration is the exchange of gas within the internal environment --> occurs in the tissues External respiration is the exchange of gas within the external environment --> occurs in the respiratory membrane

Palv

Intra-alveolar pressure: The pressure inside the alveoli. The intra-alveolar pressure always equalizes with the atmospheric pressure due to its opening to the atmosphere via the bronchioles.

Explain how oxygen in transported in the body.

Almost all oxygen is transported through the blood via the protein hemoglobin. -the iron of the hemoglobin binds loosely and reversibly to the O2 for transport. A tiny amount of oxygen is dissolved in the plasma

Define Hyperpnea

An increased depth and rate of ventilation to meet an increased oxygen demand. common causes: exercise or disease *Blood O2 and CO2 remain the same*

Define Hyperventilation

An increased rate and depth of ventilations independent from the cellular oxygen needs. common causes: anxiety or panic effects: causes low blood CO2 levels (constricts blood vessels to the brain causing dizziness), increased blood pH

How does the pons (pontine respiratory group) regulate pulmonary ventilation?

Apneustic Center: stimulates neurons in the DRG, inspiration for deep breathing Pneumotaxic center: inhibits neurons in the DRG, allows for relaxation.

What is the anatomy of the pleura? (What divisions are there)

Pleura: Two-walled sac that surrounds the lungs and contains pleural fluid Visceral layer: inner layer Pleural cavity: fluid-filled Cavity in between the two layers. Parietal layer: Outer layer that attaches the lungs to the thoracic wall

What is the difference between pulmonary circulation and bronchiole circulation?

Pulmonary circulation is the process where the blood goes from the heart, to the lungs for gas exchange, and then back to the heart. Bronchiole circulation is the process that supplies blood for conducting zone structures.

What factors influence respiratory rate?

Respiratory rate is significantly influenced by the concentration of CO2 in the blood. High Concentration of CO2: increased hydrogen ions which means decreased pH --> results in increased respiratory rate and depth in order to "blow off" CO2 Low Concentration of CO2: decreased hydrogen ions which means increased pH --> results in decreased respiratory rate and depth in order to conserve CO2

What is the difference between the conducting zone and respiratory zone?

The conducting zone consists of the structures which act as a route for in coming and out going air (ex: trachea). The Respiratory zone is consists of the structures where gas exchange takes place (ex: alveoli).

Describe the effects of high altitude on the respiratory system.

As altitude increases, atmospheric pressure decreases - O2 partial pressure decreases - Higher altitudes cause lower hemoglobin saturation - Produces more BPG --> the body secretes EPO to increase production of erythrocytes in order to increase hemoglobin in the blood.

Pulmonary ventilation

During inspiration --> lungs are pulled outward and air rushes in (following the concentration gradient) --> air pressure in the lungs < atmospheric pressure During Expiration--> thoracic wall recoils causing the lungs to compress --> air rushes out of the lungs (following the concentration gradient)--> air pressure in the lungs > atmospheric pressure

What is partial Pressure?

Each gas has its own pressure unique to other gases named P(gas) --> example P(O2)

What is the general structure of hemoglobin?

- Hemoglobin has 4 protein chains - each chain has a heme with an iron atom (this is for the binding with O2) - each hemoglobin can transport 4 O2 molecules Oxyhemoglobin: bright red Deoxyhemoglobin: dark red

What are the functions of pleural fluid?

- Lubricate pleural surfaces in order to reduce friction during respiration - Holds the lungs to the thoracic wall which allows the lungs to expand for proper inhalation. (creates surface tension against the thoracic wall)

Explain key components of fetal hemoglobin.

- Maternal and fetal erythrocytes are separated by the chorion of the placenta - fetus depends on the mother for O2: gas exchange occurs because the maternal partial pressure is higher than the fetal partial pressure and the gas travels down the concentration gradient -fetal hemoglobin binds tighter to O2 than adult hemoglobin-

Explain the different ways that carbon dioxide is transported throughout the body.

1. Some CO2 dissolves in plasma (7%) 2. Some CO2 binds to hemoglobin and gets transported to the lungs (23%) - does NOT bind to iron like oxygen - binds to the protein chain to form carbaminohemoglobin 3. The majority of CO2 is transported to the lungs by as HCO3 (bicarbonate) - Carbonic acid equation: Carbonic Anhydrase (CA) enzyme produced by erythrocytes and helps to transform CO2 and H2O to H2CO3 CO2 + H2O --> H2CO3 --> H+ + HCO3- (H2CO3 = carbonic acid ) (HCO3- = bicarbonate ion) This equation is reversible: can move both ways -moves to the right in the tissues -moves to the left in the lungs

How does the medulla oblongata regulate pulmonary ventilation?

Dorsal Respiratory Group: results in normal inhalation and stimulates the diaphragm and intercoastal muscles Ventral Respiratory Group: Results in forced breathing only and stimulates accessory muscles.

FRC

Functional Residual Capacity (FRC) = RV + ERV

What is the main function of the lungs?

Gas exchange with the atmosphere, houses both conducting zone and respiratory zone structures

Oxygen-hemoglobin disassociation curve

Shows the binding of O2 to heme with different partial pressures of O2 Cooperative Binding: as one molecule of O2 binds it becomes easier for other molecules to bind as well --> this makes the graph a curve rather than a straight line Decreased pH: curve shifts to the right Increased Temperature: curve shifts to the right

What is the function of the paranasal sinuses?

The sinuses (named after the bone they are in) warm and humidify the air coming in. They secrete mucus and allow the skull to weigh less.

What is total pressure?

The sum of all the partial pressures in a mixture.

TLC

Total Lung Capacity (TLC) = ERV + IRV + TV + RV

List the steps of air starting with the trachea

Trachea (splits at carina)--> Left and right primary bronchi --> bronchioles (no cartilage only smooth muscle: the muscular wall can change size)

What are the cells and components of the alveoli?

Type 1 alveolar cells: squamous epithelium, highly permeable to gasses, close to capillaries. Type 2 alveolar cells: secretes pulmonary surfactant, interspersed amongst Type 1 cells. Alveolar macrophages: phagocytize debris and pathogens. Respiratory membrane: allows gasses to pass via simple diffusion.

What is the relationship between volume and pressure?

volume is inversely related to pressure