Unit 4 Flashcards
1
Q
What are the functions of the respiratory system?
A
- gas exchange
- respiration (inspiration/expiration)
- **protection **(from inhaled pathogens/irritants)
- olfaction
- speech
2
Q
What are some gross anatomical differences between the two lungs?
A
Right Lung - 3 lobes
Left Lung - 2 lobes and cardiac notch
3
Q
What are the serous membranes surrounding the lungs, where are they and what is between them?
A
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.
4
Q
Describe the route of airflow during inspiration.
A
- 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
5
Q
Which structures in the respiratory tract are supported by hyaline cartilage?
A
Primarily the layrnx, trachea and bronchi.
There is some in the nose as well.
6
Q
What is special about bronchioles as opposed to other parts of the respiratory tract?
A
Most other parts are supported by relatively inflexible hyaline cartilage.
Bronchioles lack cartilage but have smooth muscle which allows bronchodilation and -constriction.
7
Q
What lines the interior of alveoli?
The exterior?
A
interior - simple squamous epithelium
exterior - alveolar capillaries
8
Q
Which part of respiration is considered an active process and why?
A
Inspiration (AKA inhalation)
- muscles contract to decrease pressure within the lungs
- the diaphragm contracts downward
- intercostals pull outward on thoracic cavity
9
Q
What is the pressure of atmospheric air at sea level?
And that of the lungs at rest?
A
760 mm Hg for both
10
Q
What is Boyle’s Law?
A
volume and pressure are inversly proportional
11
Q
To what level does intrapulmonic pressure drop during inhalation?
A
758 mm Hg
12
Q
What part of respiration causes intrapulmonic pressure to rise?
How?
To what level (mm Hg-wise)?
A
Expiration (AKA exhalation)
- muscles relax (“passive” process)
- diaphragm relaxes upwards
- internal intercostals depress and retract ribs
- pressure increases to 762 mm Hg
13
Q
What is Dalton’s Law of Partial Pressures?
A
in a gas mixture, each gas exhibits its own partial pressure and total gas pressure is the sum of partial pressures
14
Q
What are the partial pressures in mm Hg and % of the four main gases in atmospheric air?
A
- N<strong>2</strong> 597 mm Hg 78%
- O2 160 mm Hg 21%
- CO2 0.25 mm Hg 0.03%
- H20 varies varies
15
Q
What are the 5 functions of the urinary system?
A
- Filter blood plasma (25% cardiac output to kidneys)
- Regulate blood pH/pressure/volume
- Release erythropoietin
- Release renin
- Produce & excrete urine
16
Q
What are the four organs of the urinary system?
A
- Kidneys (paired)
- Ureters (paired)
- Bladder
- Urethra
17
Q
Where are they kidneys?
What are they attached to?
Why is their fixed position important?
A
- retroperitoneal posterior to liver and spleen
- attached to mesentery
- remain in place to avoid problems with renal blood flow
18
Q
What is the inner, concave portion of the kidney containing the renal pyramids called?
A
Renal medulla
19
Q
What are the arteries of the kidney?
A
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
20
Q
What is the outer, convex portion of the kidney called?
A
renal cortex
21
Q
What is the structure that collects filtrate from the glomerulus?
A
Bowman’s or glomerular capsule
22
Q
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?
A
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
23
Q
What is Henry’s Law?
A
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
24
Q
Describe gas exchange within the pulmonary circuit including specific pressures of important gases.
Draw it.
A
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.
25
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.
26
How is O2 transported in blood?
%?
**2% dissolves** into plasma
**98%** binds to hemoglobin to make **oxyhemoglobin**
27
How is CO2 transported in blood?
**7% dissolves** in plasma
**23% binds** to hemoglobin to make **carbaminohemoglobin**
**70% **exists as **bicarbonate ion HCO3-**
28
Describe the process of internal respiration with relation to CO2.
Draw it.
CO2 leaves cells as a byproduct of cellular respiration.
## Footnote
**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
29
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)
30
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
31
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
32
# 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
33
What is the most important factor in external respiration?
the pressure of O2 coming in
34
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
35
What cells are there in alveoli other than the main epithelial cells lining each one?
What do they do?
- **type 2 cells** - produce surfactant which reduces surface tension of water within alveoli, keeping it from causing them to collapse
- **dust cells - **alveolar macrophages that clean dust and microorganisms off the alveolar surfaces
36
What are the 3 parts of the filtration membrane?
1. **fenestrated endothelium** - of the glomerulus
2. **basement membrane**
3. **filtration slits** - between pedicels of podocytes
37
What is the main function unit of the kidney?
How many per kidney?
**Nephron**
**- **1,000,000 per kidney
38
What three processes occur in the nephron and in which parts?
1) **filtration** - between the glomerulus and the capsule
2) **reabsorption** - PCT, DCT, loop of Henle
3) **secretion** - mostly in DCT
39
Describe the flow of blood through the nephron.
**Afferent arteriole** enters bowman's capsule...
becomes **glomerulus** and then exits capsule as...
**efferent arteriole** which becomes...
**peritubular capillaries** near the PCT...
then **vasa recta capillaries** near the loop of Henle...
then more **peritubular** near the DCT...
40
What are the cells within the glomerular capsule that cover about 1/3 of the glomerulus?
What do they do?
**Mesangial Cells**
- filtration, structural support, phagocytosis
41
What is the glomerular filtration rate?
**125 mL/min**
or **180 L/day**
42
What wastes are excreted by the kidneys?
* **Creatinine** - from muscle metabolism
* Nitrogenous Wastes
* **Urea**
* **Uric Acid**
* **Urobilinogen** - hemoglobin metabolite
* **Hormones**
* Foreign substances
* **drugs**
* **toxins**
* **unneeded food compounds** (saccharin, benzoate, etc.)
43
Describe and draw the structure of the nephron.
the **afferent arteriole** enters the **bowman's capsule** and feeds into the **glomerulus**
the **efferent arteriole** continues out of the capsule and becomes the **peritubular capillaries** near the **proximal and distal convoluted tubules** and the **vasa recta** near the **loop of Henle** with its **ascending and descending limbs** dipping into the renal medulla
the ascending limb loops back to the afferent and efferent arteriole to form with them the **juxtaglomerular apparatus**
44
What is the combination of the glomerulus and the bowman's capsule known as?
the renal corpuscle
45
After filtrate has passed through the tubules of the nephron, where does it go?
And what is it called?
**Collecting Ducts** and then the **Renal Pelvis**
it's known as **urine** after secretion/reabsorption are complete in the collecting duct
46
What percent of plasma filters out of the glomerulus in the renal corpuscle? Why?
about **20%** or 1/5th
because if too much filtered out the blood left in the efferent arteriole would be too viscous
this is known as the **filtration fraction**
47
What are the spaces between the foot processes of podocytes?
**filtration slits**
48
What is the fluid that passes through the filtration membrane called?
What is its composition?
**filtrate**
filtrate is **plasma minus plasma proteins**, meaning **mostly water and dissolved solutes**
49
What are the 3 separate pressures involved in filtration? And the one pressure that is calculated from them?
**Blood** (or Glomerular) **Hydrostatic Pressure** - pressure of blood pushing out on glomerular capillary walls (generally **55 mm Hg**)
**Capsular Hydrostatic Pressure** - pressure of filtrate pushing back in on glomerulus from within capsule (avg. **15 mm Hg**)
**Blood** (Colloid) **Osmotic Pressure - **osmotic pressure gradient due to non diffusable proteins in plasma left in glomerulus (avg. **30 mm Hg**)
**Net Filtration Pressure** - BHP - (CHP + BOP) or 55 - (40 + 15) = **10 mm Hg**
50
What is the rate of filtration in the renal corpuscle known as?
And what is it?
**Glomerular Filtration Rate**
**125 mL/min or 180 L/day**
51
How is glomerular filtration rate kept constant?
1) **myogenic response** - intrinsic ability of vascular smooth muscle to respond to pressure change
2) **tubuloglomerular feedback** - paracrine signaling based on fluid flow in the juxtaglomerular portion of ascending limb of loop of Henle, macula densa cells send signal to afferent arteriole to constrict when NaCl delivery past it (and thus GFR) gets too high
3) **hormones/autonomic nervous system** - sympathetic innervation of afferent/efferent arterioles and _angiotensin II_ and _prostaglandins_
52
What are the two types of movement of solutes and water between tubule lumens and ECF in reabsorption?
**epithelial** (transcellular) **transport** - through tubular epithelial cells (Na+)
**paracellular pathway** - through junctions between epithelial cells
(everything other than Na+ ...anions, water, potassium, calcium, urea... can do both types)
53
Describe _direct_ reabsorption of sodium. Where does it take place and how?
in the **proximal tubule**, sodium diffuses passively into epithelial cells
then it is **actively antiported** with K+ via **Na+-K+-ATPase** into interstitial fluid
54
Describe _indirect_ or _secondary transport_ of Na+.
Where does it happen?
Sodium is **symported **with a variety of substances (glucose, amino acids, ions, organic metabolites)
ex: Na+ and glucose move into the cell of the **proximal tubule** by harnessing the energy of Na+'s concentration gradient. Na+ is then antiported with K+ into the ECF and glucose diffuses out with help from GLUT protein.
55
What is reabsorbed from the PCT?
* **HCO3- **(passive)
* **NaCl **(active)
* **H2O** (passive)
* **Nutrients **(active)
* **K+** (passive)
56
What is reabsorbed from the descending limb?
H2O only (passively)
57
What is reabsorbed from the thin segment of the ascending limb? And how?
**NaCl, passively**
58
What is reabsorbed from the thick segment of the ascending limb and how?
**NaCl, actively**
59
What is reabsorbed from the distal convoluted tubule and how?
* **NaCl** (actively)
* **HCO3-** (actively)
* **H2O** (passively)
60
What is reabsorbed from the collecting duct and how?
**NaCl, actively**
**Urea, passively**
**H2O, passively**
61
What is solvent drag?
the transport of solutes out of the renal tubule (paracellularly) by the flow of water rather than by ion pumps or transport proteins
62
What is the process of moving substances from the peritubular capillaries to the tubules?
How does it occur?
What is moved and where?
Secretion
active transport
- **H+ ions** in the PCT and DCT
- **K+** in the DCT (antiported w/ sodium via aldosterone)
- **NH3, Uric acid and Urea** in the DCT
- also drugs/toxins
63
what is obligatory water reabsorption?
renal water reabsorption that occurs as a result of osmosis
64
name the renal system that controls systemic blood pressure
its parts?
and how?
**Juxtaglomerular Apparatus**
3 parts and their special cells:
1. **afferent arteriole** (**JG cells**, stimulate constriction/dilation)
2. **efferent arteriole** (**fewer JG cells**)
3. **DCT**, loops back from other end of nephron (**Macula Densa** cells, monitor flow rate + contents, especially NaCl)
65
What do the macula densa cells do in response to flow rate changes or NaCl concentration changes?
- if flow rate is low, they signal dilation of the aff. art. and constriction of the eff. art. to increase flow rate
- if it's high, vice versa
- if NaCl is too high, they release a vasopressor to the aff. art. to decrease GFR and thus NaCl concentration
66
What do JG cells do in response to blood pressure changes?
if blood volume (and thus **BHP) is low**, they **activate prorenin** and **secrete renin**
67
what does renin do?
describe the resulting cascade and its final result
**renin** converts the liver's **angiotensinogen to angiotensin I**
the lungs' **angiotensin-converting enzyme** converts this to **angiotensin II** which...
**constricts blood vessels** and **stimulates** adrenal cortical **secretion of aldosterone** and pituitary secretion of **ADH** which...
causes **DCT reabsorption of Na+ and water (via aldosterone)** and **collecting duct reabsorption of water (via ADH)**, further **increasing BP**
68
What hormone contradicts the renin-angiotensin system?
How?
Where does it come from?
**Atrial Natriuretic Peptide**
- blocks ADH and aldosterone
- comes from the heart
- lowers BP
69
What is the system of blood and flitrate running opposite each other in the loop of Henle called?
the **counter-current mechanism**
70
what are the two fluid compartments of the body?
ECF and ICF
71
describe ECF
what % of fluids is it?
what are its two main components, their %s?
major ions?
- osmolarity?
**40% of total fluids**
**- **broken into **80% interstitial fluid** and **20% plasma**
**- **major ions: **_Na+_** (majority), **Cl-, HCO3-**
- maintained at **300 mOsM** (_280 of which Na+_)
72
describe ICF
its % of total fluids?
its ions?
its osmolarity?
- **60% of total** fluids
- **K+, anions, PO4**
- **300 mOsM**
73
what % of body weight is water?
86%
74
what are the sources of water input and their %?
**liquids (60%)**
**food (30%)**
**metabolism (10%)**
75
what are the sources of water output and their %s?
**urine (60%)**
**insensible (28%)** - lungs, skin
**feces (4%)**
**sweat (8%)**
76
What is the main control center for water balance?
**hypothalamus**
- controls thirst
- produces ADH
77
How is ADH triggered?
- plasma osmolarity above 300 mOsM
- blood volume drops
- blood pressure drops
78
what are some sources of dehydration?
- lack of intake
- excess heat
- vomiting/diarrhea
- exercise
- bleeding
79
sources of overhydration?
- renal failure
- hormone problems (too much ADH/Aldo)
- excess intake
- congestive heart failure
80
what are the 3 ways body maintains ph?
how fast do they work?
1) **buffers** - HCO3-, phosphate, proteins (**work in seconds**)
2) **respiration** - removal of CO2 **(works in 1-3 minutes)**
3) **kidneys** - secretion/reabsorption of H+ **(works in hrs to days)**
81
What is a buffer and how does it work?
a mixture of a weak acid and weak base
- accepts H+ ions in acidic conditons
- accepts OH+ ions in basic conditions
82
why is a weak acid weak?
it only partly dissociates
100 HAc becomes 90 HAc, 10 H+ and 10 Ac-
83
what is the condition of low blood ph called?
what is its pH?
how is it dealt with by the body?
metabolic acidosis
pH below 7.35
body removes H+ and retains HCO3-
84
what is the condition of high pH called?
its pH?
how is it dealt with?
metabolic alkalosis
pH above 7.45
body removes HCO3- and retains H+
85
What is the pH-related condition associated with pulmonary function called?
what causes it?
what does it result in?
**respiratory alkalosis**
- caused by hyperventilation
- **CO2 levels drop, blood pH increases**
86
what is the pH and osmolarity of urine?
pH 5-8
100 mOsM
87
