Unit 4 Flashcards
What are the functions of the respiratory system?
- gas exchange
- respiration (inspiration/expiration)
- **protection **(from inhaled pathogens/irritants)
- olfaction
- speech
What are some gross anatomical differences between the two lungs?
Right Lung - 3 lobes
Left Lung - 2 lobes and cardiac notch
What are the serous membranes surrounding the lungs, where are they and what is between them?
The visceral pleura lies on the lungs and the…
parietal pleura lines the outer border of…
pleural cavity between them which is…
filled with pleural fluid…
and lies within the thoracic cavity.
Describe the route of airflow during inspiration.
- nostrils (external nares)
- nasal cavity (across the conchae)
- pharynx (naso-, oro-, then laryngo-)
- larynx (“voice box”)
- trachea (skeletal then smooth muscle)
- bronchi (primary, secondary, tertiary)
- bronchioles (1st point w/out cartilage, sm. muscle only)
- alveoli
Which structures in the respiratory tract are supported by hyaline cartilage?
Primarily the layrnx, trachea and bronchi.
There is some in the nose as well.
What is special about bronchioles as opposed to other parts of the respiratory tract?
Most other parts are supported by relatively inflexible hyaline cartilage.
Bronchioles lack cartilage but have smooth muscle which allows bronchodilation and -constriction.
What lines the interior of alveoli?
The exterior?
interior - simple squamous epithelium
exterior - alveolar capillaries
Which part of respiration is considered an active process and why?
Inspiration (AKA inhalation)
- muscles contract to decrease pressure within the lungs
- the diaphragm contracts downward
- intercostals pull outward on thoracic cavity
What is the pressure of atmospheric air at sea level?
And that of the lungs at rest?
760 mm Hg for both
What is Boyle’s Law?
volume and pressure are inversly proportional
To what level does intrapulmonic pressure drop during inhalation?
758 mm Hg
What part of respiration causes intrapulmonic pressure to rise?
How?
To what level (mm Hg-wise)?
Expiration (AKA exhalation)
- muscles relax (“passive” process)
- diaphragm relaxes upwards
- internal intercostals depress and retract ribs
- pressure increases to 762 mm Hg
What is Dalton’s Law of Partial Pressures?
in a gas mixture, each gas exhibits its own partial pressure and total gas pressure is the sum of partial pressures
What are the partial pressures in mm Hg and % of the four main gases in atmospheric air?
- N<strong>2</strong> 597 mm Hg 78%
- O2 160 mm Hg 21%
- CO2 0.25 mm Hg 0.03%
- H20 varies varies
What are the 5 functions of the urinary system?
- Filter blood plasma (25% cardiac output to kidneys)
- Regulate blood pH/pressure/volume
- Release erythropoietin
- Release renin
- Produce & excrete urine
What are the four organs of the urinary system?
- Kidneys (paired)
- Ureters (paired)
- Bladder
- Urethra
Where are they kidneys?
What are they attached to?
Why is their fixed position important?
- retroperitoneal posterior to liver and spleen
- attached to mesentery
- remain in place to avoid problems with renal blood flow
What is the inner, concave portion of the kidney containing the renal pyramids called?
Renal medulla
What are the arteries of the kidney?
Renal artery leads to…
Interlobar arteries between pyramids lead to …
Arcuate arteries at the base of pyramids lead to…
Interlobular arteries which stick up into the medulla and branch off into…
Afferent arterioles of the nephron
What is the outer, convex portion of the kidney called?
renal cortex
What is the structure that collects filtrate from the glomerulus?
Bowman’s or glomerular capsule
From what special vessel do substances move from blood into the tubule system of a nephron?
What is special about it?
What surrounds it?
What process does it play a major role in?
Glomerulus
- it is made up of fenestrated capillaries
- surrounded by podocytes whose pedicels create filtration slits
- is the site of filtration of blood plasma into the bowman’s capsule and tubules
What is Henry’s Law?
Every gas has a ‘solubility coefficient’ that is a measure of its ability to dissolve into solution.
CO2 is most soluble
then O2
then N2
Describe gas exchange within the pulmonary circuit including specific pressures of important gases.
Draw it.
Outside air enters the lungs with O2 and CO2 pressures of 160 and 0.25 mm HG, respectively.
It mixes with intrapleural air to make pressures of about 105 and 40 in the lungs during inhalation.
Deoxygenated blood in alveolar capillary pressures of 40 and 45 create a gradient through which O2 moves into blood and CO2 moves out to lungs.
Oxygenated blood leaves the lungs with O2 and CO2 pressures of 85-100 and 40.
Describe gas exchange in the systemic circuit, using exact pressures of important gases.
Draw it.
Oxygenated blood leaves the heart with O2 and CO2 pressures of 100 and 40 mm Hg.
Intracellular pressures of 40 and 45 create a gradient through which O2 moves into cells and CO2 moves out.
Deoxygenated blood leaves cells with pressures of 40 and 45 to return to heart/lungs.
How is O2 transported in blood?
%?
2% dissolves into plasma
98% binds to hemoglobin to make oxyhemoglobin
How is CO2 transported in blood?
7% dissolves in plasma
23% binds to hemoglobin to make carbaminohemoglobin
**70% **exists as bicarbonate ion HCO3-
Describe the process of internal respiration with relation to CO2.
Draw it.
CO2 leaves cells as a byproduct of cellular respiration.
7% dissolves in plasma.
23% binds to Hb to make carbamino-Hb
70% becomes bicarbonate buffer through these steps:
1) diffuses into RBCs
2) reacts with H2O in presence of carbonic anhydrase to form H2CO3
3) carbonic acid dissociates to H+ and HCO3-
4) chloride shift occurs, exchanging plasma Cl- for RBC’s HCO3- to make blood buffer
Describe the process of internal respiration with relation to O2.
Draw it.
2% of O2 diffuses from solution in plasma to cells
98% is removed from oxyhemoglobin and sent to cells (deoxygenated hemoglobin takes up H+ from carbonic acid)
What 3 factors affect O2 unloading from HbO?
1) temperature - higher temps = faster unloading
2) CO2 concentration - higher CO2 = faster unload, b/c more H+ ions are available from carbonic acid to bind to Hb once O2 leaves
3) acidity/pH - higher acidity/lower pH = faster unload
What is the most important factor in internal respiration rates? Why?
CO2 production
because it produces more H+ ions which increase acidity and can buffer unbound Hb
and it is a result of increased cellular respiration rates and thus drives RBCs to release O2 to feed respiration
Define and describe external respiration.
Draw it.
- external respiration is gas exchange between RBCs and alveoli
- 7% of CO2 and 2% of O2 diffuse between plasma and alveolus
- 23% of CO2 unbinds from Hb and diffuses out into alveolus
- 98% of incoming O2 binds to H+-buffered Hb, producing HbO2 and H+ ions
- Chloride shift reverses, sending Cl- out of RBC in exchange for bicarbonate which grabs H+ ion to make carbonic acid
What is the most important factor in external respiration?
the pressure of O2 coming in
What are the three parts of the respiratory membrane?
1) alveolar epithelium - simple squamous epithelium made of type 1 cells
2) basement membrane - of both alveolar epithelium and capillary endothelium
3) endothelium - of alveolar capillary