Lectures 4, 5, 6 - Physiology Of Respiration Flashcards
Tidal volume (TV)
Vol moved into and out of respiratory tract during normal respiratory cycle 0.5L
Inspiratory reserve volume (IRV)
Max vol that can be moved into respiratory tract after a normal inspiration 3.0 - 3.3L
Expiratory reserve volume (ERV)
Max vol that can be moved out of the respiratory tract after a normal expiration 1.0 - 1.2L
Residual volume (RV)
Vol remaining in respiratory tract after max expiration 1.2L
Vital capacity (VC)
Total amount of exchangeable air
TV + IRV + ERV
Pulmonary capacities
The sum of 2 or more pulmonary volumes
Inspiratory capacity (IC)
TV + IRV
The max amount of air an individual can inspire after normal expiration 3.5 - 3.8L
Functional residual capacity (FRC)
ERV + RV
amount of air left in lungs at the end of normal expiration 2.2 - 2.4 L
Total lung capacity (TLC)
TV + IRV + ERV + RV
Total vol of air a long can hold (5.7 - 6.2L)
Dead space volume
Air that does not contribute to gas exchange ~30% of TV
Alveolar ventilation volume
TV - Dead Space
Total minute volume
TV (ml/cycle) x respiration rate (cycles/min)
•Typically ~6000mL/min
Alveolar ventilation
Vol of inspired air that actually reaches the alveoli -> only this vol of air takes part in gas exchange btw air and blood
Anatomical dead space
Air in passageways that don’t participate in gas exchange (ex. Pharynx, larynx)
Physiological dead space
Anatomical dead space + the volume of any nonfunctioning alveoli
• alveoli must be properly ventilated for adequate gas exchange
Alveolar perfusion
Blood flow to alveoli
How is alveolar perfusion accomplished
Vasoconstriction and vasodilation
Matching ventilation and perfusion
Maximizes gas exchange
Organs of upper respiratory tract
Nose, nasal cavity, sinuses, pharynx
Organs of lower respiratory tract
Larynx, trachea, bronchial tree, lungs
Respiratory areas
Groups of neurons in brainstem that control breathing
• adjust rate & depth of breathing
• center of medulla and group of the pons
Factors affecting breathing
Partial pressure of oxygen PO2 •partial pressure of carbon dioxide PCO2 •degree of stretch in lungs •emotional state •level of physical activity •changes in blood PH
Hering-Breuer reflex
- Step 1: motor impulses travel from respiratory center to diaphragm & intercostal muscles
- Step 2: contraction of these muscles cause lungs to expand stimulating mechanoreceptors in the lungs
- Step 3: inhibitory impulses from mechanoreceptors back to respiratory center prevent over inflation of the lungs
Mechanorecptors
The bronchi and bronchioles: detect stretching and inhibits inspiration thus provoking expiration (prevents tearing of alveoli)
Control of respiratory rhythm is essential for
Chemical regulation (concentration of gases maintained at optimal levels)
Partial pressure
•In gases pressure of 1 gas related to its concentration
•gases will dissolve in liquid until partial pressure s are equal
PO2 lungs~ PO2 blood
Gas exchange at lungs
Oxygen into blood and CO2 removed from blood
4 factors that contribute to rate of exchange in external respiration
- O2 pressure gradient
- total functional surface area of resp membrane
- repiratory minute volume
- alveolar ventilation
Key structural features of lungs and resp system
- Walls of alveoli and capillaries very thin
- Have extreamly large surface area
- Lung capillaries accommodate a large amount of blood
- Blood distributed so each RBC is very close to alveolar air
Respiratory membrane
- Part of wall of alveoli made of cells that secrete surfactant (type 2 cell)
- bulk of wall of alveolus consists of simple squamous epithelium (type 1 cells)
- both layers make resp membrane through which gas exchanged
Diffusion through resp membrane
concentration gradient drives diffusion
- resp membrane normally thin and gas exchange rapid
Gas transport in blood
Gases transported by specific carriers or dissolved directly as solutes
- chemically CO2 and O2 both react after dissolving
- allows more gas to dissolve in blood
Hemoglobin
- Reddish pigment in RBC
- quarternary protein with 1 iron (Fe) atom also called heme group
Transport of oxygen
- actual concentration in plasma is low
- 1g Hgb can carry 1.34 mL of O2
- equilibrium of Hgb and O2
Oxyhemoglobin dissociation curve
- amount of O2 released from oxyhemoglobin increases with: PCO2, PH of blood, Temperature
Transport of CO2
- Carbamino compounds are created when CO2 binds to and amino group
- mainly formed with Hgb = carbaminohemoglobin
- equilibrium reaction
- bicarbonate ions formed when CO2 dissolves in H2O
- catalyzed by an enzyme: carbonic anhydrase
- 2 step reaction, equilibrium
Chloride shift
Bicarbonate (HCO3-) ions diffuse out RBCs
- Chloride (Cl-) ions from plasma diffuse into RBCs
- electrical balance maintained (electrical equilibrium)
Carbon dioxide and PH
- all equilibrium with CO2 produce H+ ions
- this lowers PH of blood ( increases acidity)
- important consequence for homeostasis
Internal respiration
Systemic gas exchange btw blood and tissue cells, oxygen unloaded CO2 loaded
Eupnea
Normal respiration rate
Hyperpnea
Increased respiration rate
Apnea
Lack of breathing
Dyspnea
Difficult breathing
Hyperventilation
Increased respiration rate and volume.
-body reaction to increased levels of CO2 or acids in blood
Why we breath?
ATP production and CO2 generation forming carbonic acid
Ventilation
Movement of air into and out of lungs
External respiration definition
Exchange of gases between air in lungs at the alveoli and the blood
Transport of gases definition
Binding and disassociating of gases into blood and RBCs for movement through body
Internal respiration definition
Exchange of gases between blood and cells
Cellular respiration definition
Process of using oxygen to generate ATP at cellular level
Upper respiratory tract function
- Passageways for respiration
- receptor for smell
- filters incoming air of large foreign material
- moisten and warms incoming air
- resonating chamber for voice
Nose
Air filtered, warmed, moistened, chem examined
- vibrissae( nose hair) filter large particulates
- conchae slows and stirs (3 levels)
- mucus membrane rich blood supply and filters
Nasal cavity
Mucus layer that’s secreted by goblet cells to catch particulates
Paranasal sinuses
Sun-filled spaces for buoyancy and fluid storage and circulation
- maxillary
- frontal
- ethmoid
- sphenoid
Pharynx and 3 portions
Back of oral cavity between nasal cavity and larynx - 3 portions Nasopharynx Oropharynx Laryngopharynx
Larynx
Maintains open airway, routes food and air, assists sound production
- below pharynx above trachea
- made of muscle and cartilage
Intrinsic and extrinsic muscle group
Larynx cartillage
Thyroid, cricoid, epiglottic
Accessory cartilage: arytenoid, cuneiform, carniculate
Trachea
“Windpipe” transports air to and from lungs
Extends down in front of esophagus into thoracic cavity and splits into left and right primary bronchi
Bronchial tree components
R and L primary bronchi Secondary or lobar bronchi Tertiary or segmental bronchi Alveolar ducts Alveolar sacs Alveoli
Veins in body vs in lungs
In body veins carry deoxygenated blood back to heart
In lungs carry oxygenated blood to heart
Always going to heart
Arteries in body vs in lungs
Arteries in body carry oxygenated blood from heart to various part of body
In lungs artery carry deoxygenated blood from heart to lungs and alveoli
Always away from heart
Lungs structure
Soft spongy cone shaped organs
R - 3 lobes and 2 fissure ( oblique and horizontal)
L - 2 lobes to make room for heart and 1 fissure (oblique)
Contains :
Stroma - elastic CT
Blood vessels
Motor neurofibers (parasympathetic and sympathetic)
Pleura (÷ thoracic cavity into 3 mediastinum, R and L lung)
Immune system in respiratory 2 cells
Goblet cells = traps particles and slows foreign bodies Mast cells = provide parasitic immunity with histamines
Pulmonary ventilation
Act of breathing in and out
Inspiration
Diaphragm flattens creating vacuum pulling air into lungs
Expiration
Diaphragm and muscles relax and push air out of lungs
Primary principal of ventilation
Air moves from area higher pressure to area lower pressure ( down its pressure gradient)
Pb
Atmospheric pressure (barometric pressure) at sea level 760 mmHg
Pa
Alveolar pressure (dynamic)
Pip
Itrapleural pressure
Boyles law
P1V1 = P2V2
Decreasing volume increases collision which increases pressure
Ideal gas law : PV = nRT
Cellular respiration and 3 steps names
Process where cell uses oxygen to break down glucose to H2O sand CO2
Glycolysis
Citric acid cycle
Elcwctron transport chain (ETC)
Glycolysis ( word break down)
Sugar - break down
Glycolysis: where it happens and what comes out of it
Occurs in cytosol of cells
- anaerobic process
- some ATP and NADH (electron carrier) produced
- makes 2 Pyruvate that can then enter aerobic or anaerobic pathways
Glycolysis steps
Glucose 6C-> uses 2 ATP and leaving 2 ADP to break down to Fructose 1, 6 - biphosphate -> uses 2 x 2 ATP leaving 2x2 ADP and 2x2 NAD+ leaving 2x2 NADH to break down to 2 x Pyruvate (3C)
Total production 2-Pyruvate, 4-ATP , 4 NADH
Net reaction Glycolosis
Glucose +2NAD+ + 2ADP +2Pi –> 2 Pyruvate + 2 ATP + 2 NADH
Pi = phosphate group
Citric acid cycle basic function
Takes pyruvate created in glycolysis and does repeating set of reactions that remove CO2 and electrons
- creates NADH and FADH2 to be used in ETC
- uses coenzyme A (CoA)
- occurs in mitochondria and uses alot of enzymes w
Citric acid cycle net reaction
Pyruvate +4NAD+ + FAD + ADP + Pi + H2O –>
3CO2 + 4NADH + FADH2 + ATP
This reaction happens twice as 2 pyruvate from glycolysis
Glycolosis to CAC
Pyruvate gets rid of 1 CO2 to gain CoA creating Acetyl CoA
- then losses CoA to enter Krebs cycle
What happens to CO2 lost in transition to Krebs cycle and during cycle itself
Get put back into blood to be transported back to lungs fo gas exchange
When is majority of ATP
In ETC up to 34
Structure of mitochondria membranes
Outer : selectively permeable and surrounds mitochondria
Inner: folds inward to form surface for cellular respiration
Where does ETC occur
Between inner and outer membrane of mitochondria
How does ETC produce ATP
Using NADH and FADH2 created in CAC they carry e- to mitochondria.
Special proteins in mitochondria membranes break them down to release the e- then carry them across proteins in membrane to create ATP .
How are hydrogen ions pumped out of mitochondria matrix
Energy from electrons jumping off NADH &FADH2 push H+ ions out
What is final e- acceptor in ETC
O2 and this creates H2O( reason breathing vital)
What finally creates the ATP in ETC
H+ ions coming back into mitochondria matrix through specialized protein pump mixing with ADP to make ATP
