#4 Lecture Flashcards
(172 cards)
1
Q
4 steps to obtain O2/ eliminate CO2
A
- Pulmonary ventilation (breathing)
- External respiration (diffusion)
- Transport of respiratory gases
- Internal respiration (diffusion)
2
Q
- Pulmonary ventilation (breathing)
A
Muscle contraction of diaphragm moves air in and out
3
Q
- External respiration (diffusion)
A
- O2 diffuses from lungs to blood
- CO2 diffuses from blood to lungs
4
Q
- Transport of respiratory gases
A
Cardiovascular system moves O2/CO2
5
Q
- Internal respiration (diffusion)
A
-O2 diffuses from blood to tissues
- CO2 diffuses from tissues to blood
6
Q
Alveoli is the functional unit of
A
External respiration
7
Q
Boyles law
A
Pressure of gas varies inversely with volume
- in closed area, if you increase volume, pressure decreases
- in closed area, if you decrease volume, pressure increases
- bulk flow of air will go from region of high pressure to low
8
Q
Due to Boyce’s law, changing volume of thoracic cavity causes an…
A
Inverse change in the pressure of lungs
- volume change via muscle contraction
9
Q
Inhalation
A
Thoracic cavity volume increase, pressure decreases, ai moves from high P to low AP into lungs
10
Q
Exhalation
A
Thoracic cavity volume decrease, pressure increases, air moves from high P to low P out of lungs
11
Q
Upper respiratory system
A
Nose
Nasal cavity
Paranssal sinuses
Pharynx
12
Q
Lower respiratory system
A
Larynx
Trachea
Lungs
Bronchi/bronchioles
Alveoli
13
Q
Air movement towards exchange surfaces (lungs)
A
Air enters nostrils, where it’s filtered, warmed, humidified in nasal cavity
- air moves to pharynx, where it proceeds through larynx
- pass through epiglottis/esophagus and moves down trachea
- trachea branches into two main bronchitis, one leading to each lung
- bronchi then branch into bronchioles
- alveoli at end of bronchial tree are where air enters body
14
Q
What do the smallest bronchioles have on their tips
A
Have airmsacs clustered on their tips, called alveoli
15
Q
Where does gas exchange occur between in alveoli
A
Between epithelial cells and dense capillaries
16
Q
What do alveoli lack
A
Lack cilia and mucus for protection instead have,
Surfactant fluid
17
Q
Surfactant fluid
A
Protect alveoli
- reduce surface tension
- keep sacs open
18
Q
Alveoli has exchange process
A
O2 rapidly diffuses across epithelium into capillaries and cardiovascular system
- CO2 rapidly diffuses from capillaries, across epithelium and into alveoli
19
Q
Gases dissolve in liquid according to
A
(Henry’s) Partial pressure
20
Q
A
21
Q
Henry’s law
A
When gas is in contact with a liquid, gas will dissolve in proportion to its partial pressure
22
Q
What does Henry’s law correlate with
A
Gas enter/leave according to strength and direction of pressure gradient
- allows us to treat movement of gases like diffusion
23
Q
Lower partial pressure (Henry’s law)
A
Slower the gas will dissolve into liquid
- why high altitude is hard to breath
- diffusion too slow at low pressure
24
Q
Higher partial pressure (Henry’s law)
A
Faster the gas will enter/leave into liquid
- why the bends are a problem
- gas(N2) breathed in at higher pressure leaves too quickly if ascend too fast
25
However, concentration of gases that are dissolved in liquid are affected by some additional factors (Henry’s law)
1. Partial pressure exerted by surroundings
- contraction of lungs
2. Solubility of gases
- oxygen less soluble than CO2
3. Temperature
- sodas go flat quicker at room temp
26
___ law is why we can basically call external respiration a form of diffusion
Henry’s
27
External respiration/ diffusion Henry’s law
- low O2 blood enters from pulmonary circuit, encountering high O2 air
- high PO2 crosses membrane and enters the low PO2 blood, which is circulated
- high CO2 blood enters from pulmonary circuit, encountering low CO2 air
- high PCO2 crosses membrane and enters the low CO2 air which is exhaled
28
Gas pressures correlate with concentration levels (Henry’s law)
High pressure (high O2)
- compared to O2 level in pulmonary circuit
- high PO2 (air in alveoli)
Low pressure (low O2)
- blood in pulmonary circuit is relatively low O2 level
- low PO2 (pulmonary circuit)
29
Partial pressures promote __________ in body
Gas diffusion
30
Higher PO2 in alveoli
- PO2= 100 mmHg
- not 159mmHg, due to mixing with old air
31
Lower PO2 in blood
-PO2 =40mmHg
- tissues have extracted the oxygen
32
Higher PO2 in blood
- PO2= 100mmHg
- heart then pumps blood to tissues
33
Lower PO2 in tissues
- PO2 = 40mmHg
- tissues quickly consume oxygen, keep levels low
34
Ficks law of diffusion shows how number of factors influence…
Diffusion
- can see alveoli really optimized for diffusion
35
Alveoli are specially adapted to
Facilitate diffusion
36
Surface area (ficks)
Lots of small alveoli
- surfactant
- lots of branching
- infiltrate tissue
37
Membrane permeability (ficks)
Moistened air
Heated air
- pores
- generations
38
Membrane thickness (ficks)
Thin alveoli wall
Thin capillaries
- only tunica intima
- thin diameter
39
Formation of a pressure gradient will provide
Driving force for gas exchange
40
Pressures are influenced by outside environment so..
So driving force, push of oxygen into body is influenced by atmospheric pressure
41
Atmospheric air pressure is measured in
mmHg, which is force of gas molecules pushing down
42
Atmospheric air pressure
Force of all gas molecules in atmosphere pushing down onto a surface
- mmHg(barometer)
- measured in atm
- standard sea level pressure= 1 atm
- 1 atm=-14.696 PSI 760mmHg
43
Atmospheric composition
- nitrogen (N2)=1 N² 78.6%
- oxygen (O2) = 20.9%
-water (H2O)= 0.46%
- carbon dioxide (CO2) = 0.04%
44
Dalton’s law
Gas pressures in mixture correlate with concentration
- total pressure exerted by mixture of gasses is the sum of pressures exerted independently by each gas in the mixture
45
Partial pressure (Dalton’s law)
Pressure exerted by each gas is directly proportional to the percentage of gas in mixture
46
As altitude increases, even though gas percentages stay the same , ….
Partial pressures decrease
47
It becomes harder to breathe at high altitude because
The pressure gradient lowers, which then reduces diffusion rate into the blood
48
Boyles law
When you breathe in and out..
When you breath in, thoracic cavity expands to lower pressure, so air moves in
When you breath out, thoracic cavity shrinks to raise pressure, air moves out
49
____ are also adapted to facilitate diffusion
Capillaries
50
Oxygen has low ___ in water
Solubility
51
Additional factors can affect how well gas diffuses into liquid
1. Partial pressure exerted by surroundings
- doesn’t change too much in body
2. Temperature
- doesn’t change too much in body
3. Solubility of gas
- O2 have very low solubility
52
Only about __% of oxygen into body blood is just dissolved in plasma
1.5%
53
Hemoglobin
Erythrocytes produce protein to bind/carry oxygen
- red pigment molecule that can bind oxygen
54
Hemoglobin made of four protein subunits
- 2 alpha chains (a-gene)
-2 beta chains (b-gene)
55
All protein subunits have special ____ that binds ___ (hemoglobin)
Have specia heme group that binds oxygen
56
What does heme need to work
Iron so each each Hb binds four oxygen
57
Heme group
Active parts of hemoglobin that bind oxygen
58
Colors of oxygenated and deoxygenated blood
Oxygenated= bright red
Deoxygenated = dull red
59
Oxygen binds directly to
Iron atom
- oxyhemoglobin= has O2= HbO2
- deoxyhemoglobin= no O2= HHb
60
Massive amount of needed ___ must be in RBC
Hb
61
Binding of oxygen is reversible ?
Yes
62
Hemoglobin is contained inside ____ because the massive amounts needed would:
Erythrocytes
1. Clog kidneys if dissolved in blood
2. Leak out through capillaries
3. Cause water loss via osmosis
63
Oxygen binds heme group with increasing
Affinity
64
Cooperative binding (hemoglobin)
As each O2 molecule binds to one subunit, it changes the shape of the rest of subunits to open acceptor sites of remaining subunits
- sat oxygen binding makes 2nd oxygen binding easy
-2nd oxygen binding makes 3rd oxygen binding easy easy
- 3rd oxygen binding makes. 4th oxygen binding easy easy easy
65
Cooperativity makes ___ and ___ of Hb very efficient at needed partial pressures
Binding and unbinding
66
67
Oxygen hemoglobin dissociation curve shows..
How local PO2 controls oxygen loading and unloading from Hb
68
Cooperative binding makes hemoglobin very efficient at transferring
o2 under partial pressure conditions in body
69
Cooperativity ensures get __% bound in the lungs
98%
Even if lower outside PO2 levels are present, like at higher altitudes or with reduced alveolar function
70
Does cooperative binding work in reverse?
Yes, for releasing O2, tissue unloading
- release becomes easier with less O2 bound
71
Cooperative unbinding
As each O2 molecule releases, it changes the shape of the rest of subunits so subsequent O2 molecules can unbind more easily
- 4th oxygen-binding was EASY EASY EASY EASY, but now unbind HARD HARD HARD HARD
- 4th oxygen-release then makes the next 3rd oxygen-release only HARD HARD HARD
- 3rd oxygen-release then makes the next 2nd oxygen-release only HARD HARD
- 2nd oxygen-release then makes the next 1st oxygen-release only HARD
72
Result of cooperative unbinding
Hemoglobin “hangs-on” to 4th and 3rd O2 Molecules at higher partial pressure,
but once partial pressures drop low enough, Hemoglobin quickly “dumps” remaining
O2 Molecules!
73
Heme groups also release
Oxygen cooperatively
74
At resting conditions, system tissues generate a PO2 of around 40mmHg which creates a
Pressure gradient such that 75% of Hb is still bound to oxygen
- keeps a lot of oxygen circulating in our blood, as a reservoir for later, if we need it for vigorous activity
75
At exercise conditions, systemic tissues generate much lower PO2 due to
Higher cellular respiration
76
Cooperative unbinding of Hb ensures when PO2 drops low in such conditions, remaining oxygen is quickly ___ , during the time it is needed most
Released
77
Hemoglobin binding is ____ at high PO2
78
Hemoglobin binding is ____ at low PO2
Dynamic
79
Adult systems never really get to fully 100% saturation, due to chemical, properties of
Hb
80
Survivalbility of hemoglobin binding
Even have high Hb saturation with reduced PO2 such as
- high altitudes
- disorders/ disease
81
At 40mmHg, although pressure gradient is enough to transfer O2 to tissues, level of Hb saturation is still…
High
- de O2 blood not really deoxygenated
82
Additional physiological factors can affect how well —- and —— of Hb occurs
Binding and unbinding
83
P50 (Hb)
Partial pressure at which 50% of Hb protein is bound to O2, under those physiological conditions
84
P50 values allows us to compare how the Hb saturation varies with:
1. Temperature
2. pH
3. PCO2
4. 2,3 - diphospoglycerate (2,3-DPG)
85
1. Temperature effects on Hb
High temperature shift the dissociation curve to right, which means that Hb will release O2 more easily
86
When is there higher temperature
- exercise/ vigorous activity
- cells need more oxygen
- these conditions help supply it
Low temperatures have reverse effect
87
2. pH ( blood acidity )affect on Hb
High acidity shifter the dissociation curve to right, which means that Hb will release O2 more easily
88
When is there higher acidity (Hb)
- exercise/ vigorous activity
- build up of lactic acid
- build up of CO2 (carbonate acidifies)
89
Bohr affect
Higher acidity/ higher CO2 weaken O2 binding to Hb
90
3. PCO2 ( carbon dioxide ) effects Hb
High CO2 shift the dissociation curve to the right, which means that Hb will release O2 more easily
91
When is there higher CO2 (Hb)
- exercise/ vigorous activity
- increased cellular respiration
- increased level CO2 in bloodstream
92
4. 2,3- DPG effect on Hb
High 2,3 DPG are produced by RBC’s as under anaerobic conditions as cells are metabolizing glucose
93
When are there anaerobic conditions (Hb)
Exercise/ vigorous activity
- fermentation = decreased O2 levels
- 2,3-DPG binds Hb directly to shift
94
High 2,3- DPG can also be produced via ___ and ___
Anemia and chronic hypoxia
95
What will happen to oxygen levels in the blood when I hold my breath
O2 saturation remain relatively same
96
Carbon dioxide has ___ solubility in blood
Higher
97
How is CO2 transported through blood
1. Some of CO2 dissolves straight into bloodstream
2. Significant amnt of CO2 binds to Hb-proteins, although not at iron sites
- so it doesn’t compete with O2
- binds to amino acid
- binds/unbinds due to partial pressures
- hb binding is 30%
3. Bicarbonate ions (HCO3) in plasma
- 60% of CO2
4. Systemic tissues (internal respiration diffusion)
External respiration
98
Conversion to bicarbonate in RBC then dissolving into plasma is main way to move CO2
- first RBC take up dissolved CO2 from plasma then convert it to bicarbonate
- carbonic a hydrate makes this process fast, converting CO2 into H2CO3
- H2CO3 quickly breaks down into H+ slightly acidifying blood
* help facilitate O2 offloading
* buffered by Hb itself
- bicarbonate ion then can easily dissolve in blood and move to lungs
* loss of negative ion offset Cl intake
99
100
How do we maintain needed physiological gradients that are required for these diffusion exchanges
Osmoregulation
101
Osmoregulation
Regulation of water levels and solute balance
102
To conduct Osmoregulation, organs regulate ___ ____ to influence the movement of water
Solute concentration
103
In hypotonic environment , need to __ water to survive
Lose (freshwater species)
104
In hypertonic or dry terrestrial habitats, must __ water (include humans)
Save
105
Osmolarity
Solute concentration of a solution, determines the movement of water across a membrane (osmosis)
106
Isosmotic
If both sides of membrane have same osmolarity, there is equal movement of water in both directions
107
If both sides have different osmolarity, net movement of water goes from the __ to the __ solution
Hyposmotic to hyperosmotic solution
108
Osmosis
Diffusion of water molecules through a semipermeable membrane
109
Semipermeable membrane solute and water (osmosis)
Solute: blocked
Water: passes
110
Dialysis
Solute movement from high>low concentration through a semipermeable membrane
111
Anything that changes the solute concentration in any compartment leads to
Net water flow
112
Physiological control of thirst mechanism/ ion balance still uses principles we are familiar with..
- hypothalamus control of homeostasis
- negative feedback loops
- hormone release via pituitary gland
113
How does the kidney work to accomplish regulation and excretion
Urine formation
114
Kidneys receive __% of total cardiac output, to produce about 2L of urine per day
25%
115
Nephron convert blood to urine via:
1. Glomerular filtration
2. Tubular reabsorption
3. Establishing osmotic gradient
4. Tubular secretion
116
Renal corpuscle
Site of initial filtration of blood
117
Glomerular capsule (parietal layer)
Tubule shell made of parietal cells which collects
118
119
Glomerular layer (visceral layer )
Filters blood plasma
120
Visceral layer made of…
Branching epithelial cells aka podocytes , which facilitate filtration
121
Glomerulus
Ball of capillaries contained by affected arterioles and efferent arterioles
122
Capillaries endothelium
' the Glomerulus
has Fenestrated Capillaries that ALLOWS
Plasma Fluid through…
- BLOCK Formed Elements (i.e. cells)
123
Basement membrane (renal corpuscle)
provides more
Filtration AGAINST Large Proteins:
- BLOCK Large Proteins
- BLOCK Negatively-Charged Proteins
124
Visceral layer(renal corpuscle)
filtration slits” created by
Podocytes STOP Smaller Proteins
- BLOCKS Albumin
- BLOCKS Immunoglobins (i.e. Antibodies)
125
Different layers of renal corpuscle..
Block different blood solutes
126
Larger items blocked and smaller items allowed passage into the. __ as filtrates
Nephron
127
Additional cleaning is performed by intermingled
Glomerular mesangial cells
128
Glomerular mesangial cells
engulf macromolecules and
agents caught in the filter
- especially important for
the Basement Membrane
129
Difference between blood plasma and glomerular filtrate
Blood plasma -
Has red blood cells
Glomerular filtrate
- doesn’t have red blood cells
130
Glomerular blood pressure in capillaries provides the ___ ___ _ ___ for filtration
Net driving force
131
Pressure outward from capillary
HPgc = 55 mm Hg: Hydrostatic Pressure
of Glomerular Capillaries is essentially
Blood Pressure
- push filtrate forward into capsule
132
Pressure backward from capsule
• HPcs = 15 mm Hg: Hydrostatic Pressure
of Filtrate “pushing back”, i.e. Resistance
from being moved into a Capsule with a
very small Volume / Diameter
• Opgc = 30 mm Hg: Osmosis of H2O back
into Capillary, due to HIGH Concentration
of large blood proteins
- push filtrate back into capillary
133
Glomerular blood pressure typically remains ___ than opposing forces
Higher
134
Net filtration pressure (NFP)
overall
pressure needed to ensure Filtrate moves
INTO the Capsule, to allow Filtration!
135
NFD needs to stay ___ for nephron/ kidney to keep working
Positive
136
Proximal convoluted tubule does large amount of ..
Reabsorption
137
Glomerular capillaries remerge into an ___ arterial rebranded to ___ ____ (PCT)
Efferent
Peritubular capillaries
138
Peritubular capillaries first associate with the PCT to immediately begin ____
Reabsorption
- very large amount of reabsorption occurs in PCT, including majority of reclaimed H2O
139
Aquaporins
Water channels
Osmosis
140
Urea is recovered to maintain ____ ____ , especially in kidney
Osmotic gradient
141
Almost all reabsorption excluding Na is done via passive transport (PCT)
- diffusion/osmosis
- dialysis
142
Some ____ occurs in PCT
Secretion
143
Loop of henle (nephron loop)
Limbs maximize H2O absorption and salt balance
144
Descending loop.
Only permeable to H2O absorption
- thin segments: descending limb
145
Ascending loop
Only permeable to the salt/ion exchange
- thick segments: ascending limb
146
the PCT already recovered
about 65% H2O from Filtrate
• BUT, this is STILL TOO MUCH…
H20 to be lost in urine
147
This setup of the Loop of Henle allows for
production of Osmotic Gradient that can
first
CONCENTRATE then DILUTE Filtrate,
in order to extract more H2O!
- Process is Countercurrent Multiplication
148
Counter current multiplication generates low to high ___ ___ going from cortex to medulla
Osmotic gradient
149
Kidneys has INCREASING Osmotic Gradient
as you move
interiorly, down Nephron Loops
in the Medulla
150
Differing Permeabilities of the ascending and
descending loops help setup this gradient,
notably by the
Juxtamedullary Nephrons
Allows even more Water to be RECAPTURED,
especially in the Juxtamedullary Nephrons,
by CONCENTRATING then DILUTING Filtrate
151
152
Filtrate is further ___ in descending loop, then further ___ in ascending loop
Concentrated , diluted
153
Counter exchange with vasa recta maintains appropriate
Osmotic gradients
154
Filtrate DCTentering Distal Convoluted Tubule
is Hyposmotic (i.e. Dilute), which helps:
1. ALLOW Reabsorption of MORE H2O
2. FACILITATES Secretion of MORE Solutes
155
Without Dilute Filtrate, the concentration
gradients would not be (DCT)
working in the
right direction!
156
DCT Reabsorption / Secretion is under
various Regulation via Hormones
- Parathyroid Hormone and Ca2+ Uptake
- Juxtaglomerular Complex can control
Blood Pressure via Renin / Aldosterone
157
Distal convoluted tubule
Fine tuning with more reabsorption/secretion
158
Juxtaglomerular complex steps
1. Macula Densa
2. Granular Cells
3. Extraglomerular Mesangial Cells:
159
1. Macula Densa(juxtaglomerular complex)
closely packed cells in
Ascending Limb of Nephron Loop
• Chemosensors of NaCl content
entering Distal Convoluted Tubul
160
2. Granular Cells(juxtaglomerular complex)
enlarged smooth
muscle around Afferent Arteriole
• Mechanosensors of Blood Pressure
in the Afferent Arteriole
• Secretory Granules release the
enzyme Renin
161
3. Extraglomerular Mesangial Cells:(juxtaglomerular complex)
have
gap junctions allowing communication
between two cell types…
162
Blood pressure control
• Granular Cells detect a DROP in
Pressure, and release Renin
• …OR, Macula Cells sense DROP
in Na+, signal to Granular Cells
• Renin activates Angiotensin,
which signals Adrenal Cortex
• Adrenal Cortex then releases
Aldosterone, which goes to DCT
• Aldosterone INCREASES the
Na+ Uptake in DCT, which
Increases BLOOD VOLUME,
Increasing BLOOD PRESSURE
163
Collecting duct
Fine tuning with more reabsorption occurs/ secretions
164
Is collecting duct similar to DCT
Yes it allows for last chance of reabsorption of H2O
165
As Collecting Duct descends back through
High Osmolarity region of Medulla
H2O
can PASSIVELY diffuse back into the body!
166
Additional EXCHANGES can occur:(collecting duct)
- Absorption: Urea, Na+, Cl-
- Secretion: H+, K+
167
Reabsorption of H2O can be modulated by(collecting duct)
ADH, which can change the amount of
Aquaporin Channels in Collecting Duct
168
Water reabsorption also can be modulated by ___ activity at collecting duct
ADH
169
___inside the
Glomerular Capsule, Filtering it
Hypothalamus monitor the
Water/Solute Concentration(urine formation)
Osmoreceotiors
170
If blood gets dehydrated , hypothalamus does what? (Urine formation)
Tells pituitary to make ADH
171
What can ADH influence (urine formation)
amount
of Aquaporin Channels are present in collecting duct similar
- this influences how much of remaining H20 in the filtrate is saved or lost
172
