Exchange and Breathing Surfaces Flashcards
the breeziest topic in bio, and for a good reason too.... :D
Factors proportional and inversely proportional to Diffusion!
- Prop = SA of surface, conc gradient, Temprature
- Inverse = T.O.E.S, Diffusion Distances!
Explain Fick’s Law!
RofD ∝ S.ACONC DIFFERENCE
div by TOES
aka RoR = SACD/TOES !!!!!!!!!
Why need Exchange Systems in Multicellulars?
- Larger organisms = LOWER SA:V ratio
- Meaning gas exchange system neeeded to supply ALL RESPIRING CELLS with sufficent O2
- Will support much higher metabolic demands, due to homeostasis, excretion, movement on a larger scale!
hence, smaller animals has a larger SA:V ratio……!
4 main factors affecting Gas Exchange at surfaces!
- LARGER SA: more molecules able to diffuse over larger area per unit time
- Thin, Permeable Membranes: Singles celled squamous cells contacting blood stream!
- Blood Supply: contact with network of capilleries
- Ventilation: conc of O2 remains higher outside than inside blood, moist lining, helping mantaining conc gradient!
What occurs during Inspiation and Expiration stages?
- Insp = Diaphagm contracts and flattens, intercostal muscles contract to lift ribs, pressure decreases, air is moved in
- Expir = Diaphagm relaxes and elonates, intercostal muscles ONLY contract to in forced air, pressure increases, air is moved out
The Trachea and Bronchi role in gaseous exchange system!
- Consists of C-Shaped cartilage rings, strong and flexible
- CARTILAGE HOLDS AIRWAYS OPEN during EXPIRATIONA (due to decreased air pressure)
The Bronchioles role in gaseous exchange system!
- More narrow than bronchi, smooth muscle with elastic fibres
- May contain cartilage, further from alveoli.
The Alveoli role in gaseous exchange system!
- Moist lining = gasses can diffuse more easily ino the blodstream
- moist lining contains a detergent chemical, reducing surface tension on alveoli, preventing adhesion+clumping
The smooth muscle+elastic tissue role in gaseous exchange system!
- Contractions and relaxtions can control volume of airflow within the airways!
- Unconsious control, widens more during periods of intense movement (exersise)
- Elastticity provides flexibility in diameter changing
What takes place when mammals undergo Inspiration?
- Volume of thoracic cavity increases, pressure decreases while the lungs begin to inflate (air moves from higher to lower pressure…)
- Diaphagm will contract and flatten , while external intercostal muscles contract
- Rib cage moves upward and outward, all being an ACTIVE PROCCESS (needing ATP for contactions)
What takes place when mammals undergo Expiration?
- Volume of thoracic cavity decreases, pressure increases while the lungs begin to deflate (air moves from higher to lower pressure…)
- Diaphagm will relax and curl , while internal intercostal muscles contract
- Rib cage moves down and inward, all being an PASSIVE PROCCESS, or when exersize, ACTIVE! (needing ATP for fotced contactions, otherwise due to gravity)
Ventilation affects on constricted airways, due to allergens!
- Will decrease diameter of airways, such as bronchioloes/bronchi
- more resistance during exhaling!
- more air stays within lungs, increased rate of breathing as result!
Instrument for measuring LUNG VOLUMES?
- Spirometer!
- breathing into tube, where kymograph will record volume of exhalations and inhalations
Define Tidal Volume, Vital Capacity and Total Lung Capacity
and residual air too!
- Volume of air moving into and out of lungs, resting breath
- Volume of air breathed out in strongest possibe exhalation, followed by deepest intake of breath
- Sum of air remaining after fully exhaling air from lungs and vital capacity of lungs
Finding Vital Capacity and Tidal volume on a Spirometer Trace!
- VC = Greatest Peak - Lowest Trough
- TV = Peak on Resting Breath - Trough on Resting Breath
Finding Ventilation Rate!
- Total volume of air inhaled per unit time
- Ventilation Rate = Tidal Volume * Breathing Rate
Finding Oxygen Consumption
- Peak of Tidal Breathing - Next Peak of Tidal Breathing
- CAREFULL of starting from specified time period e.g. 0 mins
or TROUGH for both subtracted!
What 4 factors makes insects respiratory system unique??
- Chitin exoskeleton = impermeable for gasses to diffuse directly through
- Large SA:V ratio = due to small size
- Most do fly = higher demand foroxygen (metabollically active)
- NO HAEMOGLOBIN = organs and insides BATHED in hemolymph (diffuses O2 straight to cells…)
Structure of insects respiratory system…..?
- Spiacles, openings found within exoskeleton surface, absorbing O2 and CO2
- Connects to TRACHEA, running the LENGTH of the insect abdomen
- Branches of into TRACHEOLES, where site of gas exchange occurs (high SA)……
Details of insects respiratory system…..?
- Spiacle will allow O2 to enter, and releases CO2, able to open/close in demand changes!
- Trachea connects to spiracle, rings of chitin to support diameter + prevents collapsing due to pressure changes! (also impermeable here..)
- branches into Tracheoles, where gas exchange occurs, surronded by HEMOLYMPH fluid (exchanging medium)
- WITHIN TRACHEOLES, filled with tracheal fluid, where can be pulled into tissueto increase SA in HIGH demand!
Structure of fish respiratory system…..?
- Composed of gill rakers (bony arch) attached to rows of gill filaments
- EACH FILAMENT composed with SECONDARY LAMELLAE, perpendicular to gill filament boosting SA of gill filament
- Capileries very close to the surface of SECONDARY LAMELLAE throughout gill filament………
filament = primary lamellae!!
Details of fish respiratory system…..?
COUNTERCURRENT FLOW!!!
1. Secondary lamellae PERP to gill filaments, with BLOOD flow opposite direction to WATER flow
2. hence, will MANTAIN conc grad across ENTIRE LENGTH of the gill filament!!
3. Less initial conc difference, meaning slower diff rate, where equilibrium NOT reached to fast, before water crosses lamellae length!!!
How does the Counter/Concureent graph show O2 diffusion?
- COUNTER = Both lines on vertical slant gradient, showing full o2 saturation into bloodstream, than water current
- CON = Curve going upwards, and downwards (like reciprocal graph), showing only HALF the o2 saruration into bloodstram, as both WATER and BLOOD reach equilibrium MUCH FASTER!
Ventilation process in Fish…..!!!
- Opens mouth, Buccal cavity volume increases, as pressure decreases = WATER FLOWS IN
- Fish opens opercula cavity, increases in volume, decreases in presssue = AGAIN WATER IN
- o2 contacts with gills, then water flows out of opurcula cavity into sea……….
- buccal and opercula cavity NEVER OPEN AT SAME TIME (or suffocates)
Ventilation process in insects…..!!!
-
Abdominal Pumping:
Insects contract and relax their abdominal muscles rhythmically.
This creates pressure changes in the tracheal system, forces air in and out, as volume of thorax changes and diameter of trachea changes (flight) - Spiracles open and close to regulate airflow and minimize water loss.
Spiracles open wider during high activity for increased oxygen intake.
Define Mass Flow!
The movement of fluid down the pressure gradient, and NOT the CONC GRAD!
Examples = Ventilation in mammals, fish and insects, Hydrostatic Pressure (cappileries) and CARDIAC CYCLE!
KNOW THE EXAMPLES!!!!!!!!!!!!!!!
Define Closed and Open circulatory system!
- O = where blood / transport fluid is NOT held in vessels
- C = Where they are HELD in vessels (not free flowing in cavity of organisms!)
Wha takes place in Open circulatory systems in INSECTS?
- Hemolymph fluid will bathe organs and tissues in cavity (aka Hemocoel)
- Contains dissolved nutrients and will allow diffusion to occour with tissues!
- Hemolymph will enter the heart via pores ( aka ostia)
- Heart will undergo persitalsis to pump hemolypmph towards head, and around body!
Disadvantages of Open Cirulatory systems in INSECTS?
- Low Pressure circulation = Slow flow of fluid in insects
- Hemolymph flow affected by body movement/LACK of movement!
Circulatory systems in amphibian/fish….?
SINGLE, CLOSED SYSTEM!
1. 1 single curcuit of blood flow, due to MUCH LOWER METABOLLIC DEMAND
2. Decreased rate of delivery of gasses, with much LOWER BLOOD PRESSURE to protect fragile gills from rapture
Circulatory systems in mammals….?
DOUBLE, CLOSED SYSTEM!
1. 2 seperate curcuits of blood flow, PULMONARY AND SYSTEMIC due to MUCH HIGHER METABOLLIC DEMAND
2. increased rate of delivery of gasses, with much HIGHER BLOOD PRESSURE to sustain demands and faster rate of waste removal!
