Lecture #8 Flashcards
Major Functions of Respiration
- Gas Exchange
- Communication
- Olfaction: sense of smell
- Acid-Base Balance
- Blood and lymph flow
Pulmonary Ventilation is:
Consist of repetitive cycle of inspiration (inhaling) and expiration (exhaling)
Respiratory Cycle
one complete inspiration and expiration
- flow of air in and out of the lung depends on pressure different inside and outside the body
The flow of a fluid is proportional to ..
the pressure different
the flow of a fluid is inversely proportional to
the resistance
Boyle’s Law
at a constant temperature, the pressure of a given quantity of gas is inversely proportional to its volume
What pulls air into the lungs
the lung volume↑,the internal pressure of the lungs(intrapulmonary pressure) ↓ and pulls air into the lungs
What pushes are out of the lungs?
If the lung volume↓,intrapulmonary pressure↑and pushes are out of the lungs
Intrapleural Pressure causes…
lungs to expand with expansion of the thoracic cage
Intrapleural pressure: is define as negative pressure that exists between the two pleural layers
Resistance influenced by:
- Diameter of the bronchioles Bronchodilation: increase in diameter of the bronchus, thus increases airflow
Brochoconstriction” decrease in diameter of bronchus, thys decrease air flow
- Pulmonary Compliance
- ease so lungs can expand
- decrease by lungs disease which the lungs are stiffened by scar tissue
What is the Iron Lung
Device used for patients with Polio, it is artificial ventilation
changes pressure on lungs so inspiration and expiration can occur
Decreased pressure = inspiration
Increased pressure = expiration
Spirometer
device that recaptures expired breath
- records rate and depth of breath, speed of expiration and rate of oxygen consumption
Spirometry
the measurement of pulmonary function
used in determining restrictive or obstructive lung disorders
Tidal volume (TV)
volume of air inhaled and exhaled in one cycle of breathing (~500 mL)
Inspiratory reserve volume (IRV):
air in excess of tidal volume that can be inhaled with maximum effort
Expiratory reserve volume (ERV):
air in excess of tidal volume that can be exhaled with maximum effort
Residual volume (RV):
air remaining in lungs after maximum expiration
Vital capacity (VC) (ERV + TV + IRV):
total amount of air that can be inhaled and then exhaled with maximum effort
Inspiratory capacity (IC) (TV + IRV):
maximum amount of air that can be inhaled after a normal tidal expiration
Functional residual capacity (FRC) (RV + ERV):
amount of air remaining in lungs after a normal tidal expiration
Total lung capacity (TLC) (RV + VC):
maximum amount of air the lungs can contain
Pulmonary Aveoli
- Squamous (type I) alveolar cells:
thin, rapid gas diffusion - Great (type II) alveolar cells: repair alveolar epithelium and secretes pulmonary surfactant that coast the alveoli
- Alveolar macrophages (dust cells): keep alveoli free from debris
Composition of air
78.6% nitrogen
20.9% oxygen
0.04% carbon dioxide
0-4% water vapour
Dalton’s Law
total atmospheric pressure is the sum of the contributions of the individual gases
Partial pressure
the separate contribution of each gas in a mixture
Composition of Air
composition of inspired and alveolar air differs because:
- Air is humidified by contract w mucous membrane
- air in alveoli mixes with residual air left from previous respiratory cycle
- Alveolar air exchanges O2 and CO2 with blood
Alveolar Molecular Gass Exchange
Gases diffuse in downward gradient until the partial pressure of each gas molecule in the air is equal to its partial pressure in the water
Alveolar Gas Exchange
is the swapping of (loading) O2 and (unloading) CO2 across the respiratory membrane
there is a film of water that covers alveolar for O2 to get in and Co2 to get out it must pass through this water film layer
Efficiency of Alveolar Gas Exchange
- Pressure gradient of gases
- Solubility of the gases
- Membrane surface area
- Membrane thickness
- Ventilation-perfusion coupling
Gas Transport
The process of carrying gas from the alveoli to the systemic tissues and vice versa
O2 is mostly transported by hemoglobin in the RBCs
CO2 is mostly transported by carbonic acid
Hemoglobin
molecule specialized for O2 transport
bind to 4 portions, and carry 4 O2 thus its 100 saturated
- helps loading at alveoli and unloading at tissues
Gas Transport of CO2
- Carbonic Acid (H2CO3) - 90%
- Carbamino Compounds - 5%
- Dissolved in plasma - 5%
Systemic Gas Exchange
the unloading of O2 and loading of CO2 at systemic capillaries
producing CO2 and using O2
Systemic Gas Exchange:
CO2 Loading
Oxygen unloading
- Co2 diffuses into the blood
- Carbonic anhydrase (CAH) in RBC catalyzes
- Chloride Shift
Oxygen unloading:
H+ binding to HbO2 reduces its affinity for O2
makes Hb release O2
Alveolar Gas exchange
reactions that occur in the lungs are reverse of systemic gas exchange
CO2 unloading
Hb loads O2, it affinity for H+ decreases, H+ dissociates from Hb and binds with HCO3
reverse chloride shift
Factors that adjust the rate of O2 unloading:
- Ambient PO2
- active tissue has decreased PO2, O2 is released from Hb - Temperature
- active tissue increase temp. promotes O2 unloading - Bohr Effect
- active tissue increase CO2, lowers pH, promotes O2 unloading - Bisphosphoglycerate (BPG)
- RBCs produce BPG and binds to Hb, allows O2 unloading
- increase temp. = promoted O2 unloading
- decrease pH = promotes O2 unloading
Acidosis
blood pH 7.35 less than
Alkalosis
blood pH greater than 7.45
Hypocapnia
Most common cause of alkalosis PCO2 <37 mmHg(less than)
Hypercapnia
Most common cause of acidosis PCO2 >43 mmHg (greater than)
Respiratory acidosis and alkalosis
pH imbalances resulting from a mismatch between the rate of pulmonary
ventilation and CO2 production
Ketoacidosis
acidosis brought about by rapid fat oxidation releasing acidic ketone bodies, reduces CO2 concentration
Hyperventilation
an be a corrective homeostatic response to acidosis, using CO2 faster than the body can produce
Hypoventilation
an be a corrective homeostatic response to alkalosis
Urinary System
consists of six organs: two kidneys, two ureters, urinary bladder, and urethra
Functions of the kidneys
- Filter the blood plasma, excrete toxic waster
- Regulate BV, pressure and osmolarity
- regulates electrolytes and acid-base balance
- secretes erythroprotein which stimulates the products of RBCs
- Clear hormones and drugs from blood
- Detoxify free radicals
- In starvation they synthesize glucose from amino acids
Waste
any substance that is useless to the body or presents in excess of the body’s needs
metabolic waste
waste substance produced by the body
Urea formation
proteins break down amino acids and remove forms of ammonia
liver converts ammonia to urea
Uric acid
product of nucleic acid catabolism
Creatinine
product of creatine phosphate catabolism
Excretion
separating wastes from body fluids and eliminating them
Four body systems that carry out excretion
- Respiratory system
- Integumentary system
- digestive system
- urinary system
The Nephron
Each kidney has 1.2 mill. nephrons
It has two parts:
- renal corpuscle
- Renal tubule
Renal Tubule
duct leading away from the glomerular capsule
Divided into:
- proximal convoluted tubule
- nephron loop
- distal convoluted tubule
Stages of Urine Formation
- Glomerular Filtration
- creates a plasma-like filtrate of blood - Tubular Reabsorption
- removes useful solutes from filtrate and returns them to the blood - Tubular Secretion
- removes wastes from the blood and adds them to the filtrate - Water conservation
Removes water from the urine and returns it to the blood
Glomerular Filration
capillary fluid exchange in which water and some solutes in the blood plasma pass from the capillaries of the glomerulus into the capsular space of the nephron
Gllomerular Filtrate
Fluid production, the fluid in the capsular space
Tubular Fluid
fluid from the proximal convoluted tubule through the distal convoluted tubule
Urine
Fluid that enters the collecting duct
Filtration Pressure a Function of
- Blood hydrostatic Pressure (BHP)
- Colloid Osmotic Pressure (COP)
- Capsular Pressure (CP)
High BP makes kidneys vulnerable to hypertension
