Respiratory System: Slides Flashcards
The respiratory system supplies —— for cellular respiration and disposes of ——. This occurs by ——
- Oxygen gas(O2)
- Carbon Dioxide (CO2)
- Diffusion
What is rate of diffusion between two regions governed by?
Fick’s Law of Diffusion
R= DA/Dp d
What ways have evolutionary changes occured to optimize rate of diffusion(R)?
- Increase Surface Area (A)
- Decrease Distance (d)
- Increase Concentration Difference (Dp)
———- can rely on direct diffusion of gases
Through outer surfaces and skin. However, more —— require system adaptations to enhance gas exchange.
- Unicellular & small organisms
2. Complex organisms
What system do insects use instead of a circulatory system for gas exchange?
Tracheal System
In a tracheal system, —— supply O2 directly to body cells
Tracheal Tubes
What type of respiratory system is most direct & effecient in active animals?
Tracheal System
Obtaining O2 is more challenging in — than —. Because of this — breathing requires greater effiecency than — breathing
- Water
- Air
- Water
- Air
How is water breathing acomplished, because it requires greater effiency than air breathing?
- Very thin respiratory surfaces
2. Unidirectional flow coupled with countercurrent exchange
What is the outfolding of body surface?
Evagination
Why are gills extremely thin?
To offset low O2 content in water by minimizing diffusive distance
Blood flows in the opposite direction of water
Countercurrent Exchange
What is an infolding of the body surface?
Invagination
Air enters the respiratory system through what?
Nasal Cavity & Pharynx
Where does air go after entering through the nasal cavity & pharynx?
It passes through the trachea into the bronchi
After air goes into the bronchi where does it go next?
The bronchi branch into bronchiole which brings air into the alveoli
What happens in the alveoli?
It is the site of gas exchange
The progressive branching creates tremendous —— for gas exchange
Surface Area
What do major branches in lungs contain for cleasning the respiratory system?
Mucus & Cilia
What are some characteristics of alveoli?
- Lack cilia & mucus
2. Covered with moist film that coantains surfactant
Reduces surface tension & prevents alveoli from collapsing
Surfactant
Pre-term babies that lack surfactatn are vulnerable to what?
Respiratory Distress Syndrome (RDS)
The process that ventilates the lungs & is the alternate inhalation & exhalation of air
Breathing
Mammals ventilate their lungs by ——— which — air into the lungs
- Negative Pressure Breathing
2. Pulls
Lung volume increases as the rib muscles & diaphragm contract
Inhalation
Passive due to elastic recoil of tissues; no muscles are contracted to expel air
Exhalation
Volume of air inhaled and exhaled during a normal breathe
Tidal Volume
Maximum volume of air that can be inhaled & exhaled
Vital Capacity
After a full exhalation, a —— of air remains
Residual Volume
What makes mammalian breathing somewhat inefficient?
Incomplete removal & shared airway for exhalation & inhalation
The main breathing control centers are in what 2 regions of the brainstem?
Medulla Oblongata & Pons
What do the medulla oblongata & pons do as the main breathing control center?
Regulate rate & depth of breathing in response to pH changes in cerebrospinal fluid to match metabolic demands
Chemosensors in the aorta & carotid arteries monitor — &— concentrations in the blood
O2 & CO2
Is the control of breathing in humans a positive or negative feedback loop?
Negative Feedback Loop
Amphibians ventilate their lungs by —— breathing, which — air — the trachea
- Positive Pressure
- Force
- Down
Amphibians have — that is used for gas exchange
Skin
Why do birds require a more efficient breathing(ventilation) system?
- They fly which is a high energy activity & requires a lot of oxygen
- Some birds fly at high altitudes where oxygen is low
Birds have 8 or 9 air sacs that function as bellows that keep the air — through the —. Instead of alveoli they have —.
- Flowing
- Lungs
- Parabronchi(air tubes)
2 Features that make ventilation in birds highly efficient:
- Air passes through lungs in — direction only
- Incoming fresh air does —— with air that has already undergone gas exchange
- One
2. Not mix
A gas diffuses from a region of — partial pressure to a region of — partial pressure
- Higher
2. Lower
Pressure exerted by a particular gas in a mixture of gases
Partial Pressure
Atmospheric pressure= ?
Percent of atmospheric O2 = ?%
Partial Pressure of O2= ?
Atmospheric Pressure= 760 mmHg
Atmospheric O2= 21% by volume
Partial Pressure of O2 = 0.21*760= 160 mmHg
Why do gases diffuse down pressure gradients in the lungs & other organs?
DIfferences in partial pressure
What determines the exchange of respiratory gases (O2 & CO2)?
Partial pressure gradients
Partial pressure gradients favor diffusion of O2 into the blood & CO2 in the air
Does this occur in alveoli or tissue capillaries?
Alveoli
Partial pressure gradients favor diffusion of O2 out of the blood & CO2 into the blood, In what?
Tissue capillaries
Does oxygen have high or low solubility in water & blood?
Low
Proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry
Respiratory Pigments
What are the 2 types of respiratory pigments?
- Hemocycanin
2. Hemoglobin
Is the majority of oxygen transported in the plasma or by the hemoglobin
98% of O2 is bound to hemoglobin
Hemoglobin increases the oxygen carrying capacity of the blood by ——
50-fold
A single hemoglobin molecule is made of how many subunit and what kind and amount is their of those subunits?
4 protein subunits: 2 alpha 2 beta
In hemoglobin, each subunit contains a — molecule
Heme
In hemoglobin, a heme molecule contains an — atom at center that binds to —.
- Iron
2. O2
Each hemoglobin can carry how many molecules of O2, & each of thos molecules are for heme group?
They can carry 4 molecules of O2, one molecule for each iron containing heme group
Among the 4 subunits what facilitates binding & offloading of O2?
Allosteric Cooperation
- Binding of first O2 facilitates binding of second
- Second facilitates binding of third
- Fourth & final O2 is more difficult to bind
What shows that these patterns are evident?
Oxygen Equilibrium Curve (Aka Oxygen Dissociation Curve)
Where does CO2 from respiring cells go & how does it get there?
It diffuses into blood
Where does most CO2 diffuse into, & it reacts with water to form what?
Most diffuses into erythrocytes & reacts with water to form H2CO3 which dissociates H+ & bicarbonate ions (HCO3-)
During carbon dioxide transport where are HCO3, bicarbonate ions transported?
Plasma
Most CO2 is transported to the lungs as — ions in the —
- HCO3, Bicarbonate
2. Plasma
In the lungs, is the relative partial pressure of CO2 in favor or not in favor of the net diffusion of CO2 out of the blood?
In favor
