Unit 6 - Gas Exchange, Circulation, and Elimination Flashcards
1
Q
Gas Exchange
A
the uptake of oxygen from the environment and the discharge of carbon dioxide
- requires specialized exchange surfaces
ex: the gills of a fish - the gills will take in the oxygen and the 02 enters the bloodstream and then travels to every part of the body
- every cell of the body need 02 and needs to get rid of C02
2
Q
Gas Exchange Diffusion
A
gas exchange uses diffusion (high to low concentration)
- oxygen is highly concentrated in the enviornment and so it crosses into the bloodstream
**diffusion occurs across moist respiratory exchange surfaces (02 and C02 can’t be exchanged if the exchange surface is dry)
3
Q
Animals in Water Getting Oxygen
A
animals in water have external gas exchange surfaces
Gills: outfoldings from body
- gills have a large surface area
- gills pick up oxygen
4
Q
Fish (with gills) Getting Oxygen from Water
A
the gills take out the oxygen and put it into the bloodtstream
- the CO2 makes its way to the gills and gets expelled
1) they have a huge surface area that’s in contact with water
2) ventilation – the water moves across the gills
3) gas exchange that occurs in the gills
- when the fish opens its mouth, the water flows across the gills and oxygen is removed from the water and taken in
- high PO2 when water flows into the mouth
- low PO2 when water flows out of the gills
5
Q
PO2
A
High PO2 = oxygen pressure is high
low PO2 = oxygen pressure is low
6
Q
Gas Exchange in the Gills
A
the gill filaments are made up of lamella
7
Q
Lamella
A
water flows over the gills in one direction while blood flows in the opposite direction through the gill capillaries
body tissues = O2 rich blood (from gills to body tissues)
- the other end = O2 poor blood bc it’s from body tissues to gills (coming from fish’s tail)
- the capillaries pick up the oxygen and put it into the bloodstream
**blood flows through capillaries in lamella (thin blood vessels where exchange happens)
8
Q
Countercurrent Exchange
A
ex: Fish
- most effecient way of exchange
***water flows in one direction and blood flows in the opposite direction
ex: if there’s a lot of Oxygen in the water, based on diffusion, the oxygen would move into the bloodstream
- at every point in the lamella, oxygen enters the bloodstream
9
Q
Tracheal Systems
A
insects use this
tracheal system = branched system of internal tubules
- the tubules bring air into every cell of the body
- simple diffusion works bc circulation system isn’t involved
- gas exchange happens at moist ends of the tracheoles
- air sacs are near organs that need a lot of oxygen
**oxygen enters and exits from the spiracle (same entrance)
10
Q
Lungs
A
lungs = infoldings of the body surface
- animals (like humans) are too big for the tracheal system to work (O2 won’t reach every cell that way)
- the body warms up and adds moisture to the air
- mucus helps trap particles (like dust) from entering the body
- cilia move the stuff you don’t want and mucus traps it
11
Q
Parts of the Lungs: Bronchi
A
trachea branches
- cilia and mucus in here
12
Q
Parts of the Lungs: Bronchiole
A
smaller trachea branches
- cilia and mucus in here
13
Q
Alveoli
A
alveoli = tip of a bronchiole
- sites of gas exchange
- the surface area of an alveoli is really big
- Oxygen and carbon dioxide diffuse across the alveoli
- alveoli are surrounded by capillaries
oxygen enters the lungs and releases it throughout the body
- bc air doesn’t touch every cell, circulation is needed
- the bloodstream takes the air and put it into every cell
**need a lot of surface area to take in a lot of oxygen and get ride of a lot of carbon dioxide
14
Q
Alveolus in Action
A
oxygen is high in alveoli and low in the bloodstream, so it leaves the alveoli and goes into the blood
- carbon is high in the bloodstream and low in the alveoli, so it leaves the blood and moves into the alveoli
- oxygen binds to the red blood cells
15
Q
Tidal Ventilation
A
we ventilate our lungs by breathing (the flow of air in and out)
inhale = the ribcage expands to suck in the air
exhale = rib cage contracts and muscles relax to push out the CO2
**we’re not effecient bc we inhale and exhale out of the same way
16
Q
Tidal Gas Exchange
A
*not very efficient
air flow moves in and out (think like tides of an ocean)
- mixes fresh and old air
- lungs in mammals don’t completely empty so the PO2 in alveoli is always much less than the PO2 outside (always more oxygen outside of our body)
- gas exchange doesn’t occur across entire respiratory surface
17
Q
Ventilation of Birds
A
- they need an efficient system bc they fly at high altitudes where there’s not as much O2
- birds have unidirectional air flow thru the lungs (don’t mix oxygen and carbon)
**ventilation requires 2 breaths
- they exhale thru the beak
18
Q
Parabronchi
A
sites of gas exchange in birds
19
Q
Bird Ventilation
A
**requires 2 breaths
1st inhilation (fills air sac)
1st exhale (moves air from air sacs to lungs)
2nd inhale (fills air sac)
2nd exhale (moves air from sacs to lungs)
**the air flows one way which is why it’s efficient
20
Q
Cross-Current Exchange
A
bird have this
- blood flows across the parabronchus into the body tissues
21
Q
Rankings of Efficiency of Oxygen
A
- Countercurrent
- Cross-Current
- Tidal
- Tracheal
22
Q
Circulatory System Needed in Gas Exchange
A
need a circulatory system to deliver oxygen from the lungs to the tissues
- need to transport carbon from the tissue to the lungs (exhale co2)
23
Q
Diffusion – No Circulatory System
A
- not every animal has a circulatory system
- animals without a circulatory system tend to be very thin and live in a moist enviornment
- need a large surface area (more area to receive oxygen)
- diffusion doesn’t work in big, thick organsisms bc they’re tissue would die waiting for nutrients thru diffusion
24
Q
Gastrovascular Cavity
A
opening between the cells
- facilitates gas exchange and exchange of nutrients
ex: in flatworms
25
Circulatory System Parts
fluid, vessels, and a pump (heart)
- heart pumps blood thru the vessels
- takes oxygen to every cell and take carbon away from every cell
- transports nurtients, hormones, and immune cells
26
Open Circulatory System
- a lot of invertabrates (animals without a spinal cord) (think insects)
- fluid - homlymph (fluid in the heart) mixes with interstitial fluid (other fluids of the body)
- the fluid goes in and out
tradeoffs = doesn't require a lot of energy, but can't move nutrients and other stuff quickly
(think of an open circuit)
27
Closed Ciruclatory System
vertebrates and inverts
fluid = blood in closed vessels
- the blood is separate from the interstitial fluid (blood doesn't mix)
- this takes a lot of energy but delivers oxygen, nutrients, hormones, and immune cells quickly
**blood has red blood cells (hemolymph doesn't have blood cells)
(think of a closed circuit)
- the pumping of the heart pushes blood thru the blood vessels
28
Parts of a Closed Circulatory System
closed circulatory systems are also called cardiovascular systems
- a heart (pump), arteries, and veins
- they contain blood (the fluid)
29
Closed Circulatory Systems: Arteries
carry blood away from heart
- arterioles (smaller branches)
- they get blood from the heart
- under high pressure
- thick and elastic (need thick tissue bc they're under pressure)
30
Closed Circulatory Systems: Capillaries
small vessels with thin walls (site of gas and nutrient exchange)
- blood slows down here
- they surround tissues and exchange surfaces (gills and lungs)
- blood slows down in capillaries
- very thin walls (single cell layer thick)
- only 1 red blood cell width
31
Closed Circulatory Systems: Veins
carry blood back to the heart
- under less pressure than the arteries
- thin and their walls are thin
- have valves
- the blood gets slower so the valve helps the blood move the vein toward the heart
32
Closed Circulatory Systems: Heart
full of blood and pumps blood into the arteries, then the capillaries, then the veins, and then back to the heart
33
Valves
valves push the blood flow in the veins to the heart
- they make sure the blood doesn't pool and gets to the heart
- muscles in the walls of veins also help get blood back to the heart (the muscles contract)
ex: think about getting blood from your legs all the way back to your heart
34
Varicose Veins
an example of damaged valves
- need blood to not pool or go backwards but bc valve is damaged, the blood pools
35
Why Does Blood Slow Down in the Capillaries
blood flow slows down
- there are so many capillaries that the surface area of them all added together
- the area of the capillaries is a lot bigger than in the arteries
36
Atrium
the chamber that receives blood
37
Ventricle
chamber that pumps out blood
38
Single Circulation
single circulation = blood travels body in a single loop
- blood flows thru the heart once
- heart pumps once to take blood to respiratory surface (gills) and to body (where it slows down)
- muscles contract which speeds up circulation
- the blood moves slow when it's far from the heart
ex: fish
- gill capillaries pick up the oxygen
39
Double Circulation - Pulmocutaneous Circuit
pulmocutaneous circuit = blood and skin
double circulation uses to 2 circuits of blood flow (blood flows thru the heart twice)
1. right side of the heart pumps poor oxygen blood into the capillary beds and moves oxygen in
2. left side of the heart pumps oxygen rich blood to the rest of the body
the 3 chambered heart/ventricles not divided = results in mixing oxygen rich and oxygen poor blood
***somewhat inefficient but adaptive
40
Intermitten Breathers
only breathe thru lungs when on land and breathe thru skin underwater
- ex: frogs do this
- when they're underwater, frogs shut off blood flow to lungs and shift it to the skin
41
Double Circulation - Pulmonary Circuit
uses 2 circuits of blood (blood flows thru the heart twice)
1. right side pumps oxygen poor blood into capillary blood
2. left side of heart pumps oxygen rich blood to the rest of the body
4 chambered heart (ventricles are divided)
- oxygen rich and oxygen poor blood don't mix
**highly effecient system
42
Blood
4 major parts:
Plasma -- the liquid portion of blood
- contains dissolved nutrients hormones, dissolved gasses
---------
cellular part of blood:
Red blood cells -- transport oxygen
- 99% is red blood cells
platelets -- help form blood clots
ex: if you get a cut, platelets repair damaged tissue
white cells -- immune defense
- fights off infection
43
Red Blood Cells
red blood cells = erythrocytes
- they transport oxygen
- red blood cells make up 99% of the blood's cellular part
- each RBC has 250 million hemoglobin
hemoglobin = contains iron which makes blood red
- no nucleus, mitochondria, or cytoplasm
- made in bone marrow
- red blood cells are flat which increases surface area
44
Hemoglobin
protein in red blood cells that transports oxygen
- 4 strands of hemoglobin
- have heme groups with iron at the center
- each iron binds to 1 oxygen molecule
***a hemoglobin can carry 4 oxygen molecules
- if there's oxygen it binds to hemoglobin
- when one oxygen binds to a subunit of hemoglobin, the shape changes to increase the amount of oxygen
oxy --> when oxygen binds
deoxy --> when oxygen isn't bound to hemoglobin
45
Coopertivity
when oxygen binds and unbinds to a subunit of hemoglobin
oxy --> when oxygen binds
deoxy --> when oxygen isn't bound
the shape of hemoglobin changes when oxygen is bound and not
- when oxygen binds to hemoglobin, it makes it easier for more oxygen molecules to bind
46
Oxygen unbound to hemoglobin
when there's no oxygen, it decreases the oxygen binding to hemoglobin
- when oxygen is released from one subunit of hemoglobin the shape changes to decrease affinity for oxygen (once one oxygen gets released, more get released)
***carbon monoxide binds irreversibly to hemoglobin which prevents oxygen from binding
- causes death bc you can't get air (since the oxygen isn't binding)
47
Oxygen Hemoglobin Dissociation Curve
a drop in oxygen causes oxygen to unload
- as the oxygen makes its way from the lungs to the body cells, the oxygen becomes less available
- the oxygen gets released from hemoglobin as you unload the oxygen to the body cells
- the oxygen gets released a lot faster once it gets to body tissues
**line is a curve not linear bc it gets released at different times/amounts
***not a straight line bc of cooperativity
48
Carbon Dioxide Transported Thru Bloodstream
co2 gets released and enters into the bloodstream, goes to lungs and then gets exhaled
3 ways this happens:
1. 7-10% of C02 gets dissolved and goes to lungs
2. 23% binds to hemoglobin
3. 60-70% enters Red blood cell
- carbonic acid gets transformed into bicarbonate
- then it gets reversed in the lungs
49
EPO (Hormone)
Hypoxia = low oxygen
- detected by the kidney
- kidney released EPO hormone into bloodstream
- EPO causes bone marrow to make red blood cells
- now, there's more red blood cells made with oxygen
- the kidney detects the high oxygen so no more EPO released
ex: in high altitude, it gets easier to breathe bc you make more red blood cells
***negative feedback loop maintains red blood cells
50
Athletes Train in High Altitude
they train at high altitudes to compete at sea level
- you make more red blood cells at high altitude so when you go to lower altitude you have more oxygen bc you have more red blood cells
- some athletes inject EPO (this is banned)
- hard to detect bc your body naturally makes EPO
51
Respiratory Adaptation
some animals have genetically changed their system to be able to live
deep sea diving animals have:
1. more blood (can store more oxygen)
2. more myoglobin (oxygen storing protein made in muscle)
- 02 binds to myoglobin
3. blood not routed to muscles (muscles uses myoglobin)
4. they swim efficiently
52
Nitrogenous Waste
Nitrogenous Waste = any waste product that contains nitrogen
breakdown nitrogen containing molecules
- then the removal of nitrogen containing amino acids leads to nitrogren containing group
- nitrogenous waste is toxic to cells so we need to get rid of it
53
3 forms of nitrogenous waste
Ammonia, Urea, and Uric Acid
54
Nitrogenous Waste Differs
some animals will change their nitrogenous waste type over development
ex: tadpoles
- they use ammonia and then later urea when they live on land
55
Ammonia
most aquatic animals (fish, marine invertibrates)
toxicity = high
energy cost = low
- you can swim away from it
- the low cost outweighs the toxicity and water loss
water loss = high
- can lose a lot of water but they're surrounded by water
excreted = in water
- ammonia is usually released thru the gills
- not stored in the body (need to get rid of ammonia immediately)
56
Urea
mammals, sharks, some bony fishes (terrestrial animals)
toxicity = medium
energy cost = medium
- ammonia is converted into urea which requires ATP
water loss = medium
Excreted = with water (in urine)
- urea is less toxic than ammonia so it can be stored in the bladder
- doesn't get extreted all the time (reduces water loss)
57
Uric Acid
birds, reptiles, insects
toxicity = low
Energy cost = high
- takes more metabolic steps to covert uric acid from ammonia
water loss = low
- not that much water in uric acid
excreted = as a paste
- they don't store uric acid
58
Kidney Functions for Elimination
kidneys filter nitrogenous waste out of the blood
- kidneys are important for osmoregulation (salt and water balance)
- tubular structures in kidneys
- tubules remove or absorb ions
- tubules remove or take up water
59
Filtrate
a fluid that has passed thru a filter
60
Overview of Excretory System Function
blood enters the top of the tubule
- it gets squeezed thru a filter
- the plasma (liquid part of the blood) enters the tubule
**this is now the filtrate
- the cellular part of blood (with red blood cells) stays in the capillary
- the plasma continues moving down the tubule and then urine gets excreted
61
Reabsorption
some thing that were squeezed out of the filtrate need to be reabsorbed
- removes useful solutes (glucose, salts, vitamins, hormones) and water from the filtrate and returns them to the blood
62
Secretion
adds solutes (wastes) to the filtrate
63
Excretion
we're left with the final filtrate (just urine with some water) and it leaves the body
64
Kidney Anatomy
Renal Cortex = outside of the kidney
Renal Medulla = inside of the kindey
Renal Pelvis = filtrate enters this
***renal = refers to kidneys
65
Nephrons
functional units of the vertebrate kidney
- they're filtering units
***the filtrate travels thru the nephrons
- we have 1 million nephrons
66
Juxtamedullary Nephron
they have longer tubules
- important for getting rid of the nitrogenous waste
67
Cortical Nephron
the functional units of the vertebrate kidney
68
1.5 Liters of Fluid Leaves Body
the water gets pulled out of the filtrate bc 99% of water and valuable solutes are reabsorbed (we need them)
- that's why there are blood vessels around the nephron
69
Glomerulus
ball of capillaries in Bowman's capsule (where filtrate is first formed)
70
Kidneys Using Osmosis
the water follows the salt
ex: less salt in the kidney tubule with filtrate
- the water will follow the higher concentration of salt (to the interstitial fluid)
***water moves by osmosis from low to high concentration of the solute (salt)
***solutes (salt) doesn't move across the membrane
71
Bowman's Capsule
filtrate is formed in the bowman's capsule
- here, everything is in the filtrate (waste products, glucose...) and lots of water
72
Why you need to go thru all of the steps of Blood filtrate to urine
there's lots of water in the filtrate in the beginning
- you don't want to lose the water which is why it's good to go thru all of the steps instead of just urinating first (you would be dehydrated!!!)
73
Proximal Tubule
filtrate reaches proximal tubule
- bloodstream takes out the stuff it need to keep and not urinate out
capillaries secrete and reabsorb -- ions and water nutrients are reclaimed
- the bloodstream secretes everything going into the tubule
74
Descending Loop of Henle
reabsorbs water
- water gets reabsorbed thru osmosis bc solute concentration is higher in the interstitial fluid
**water leaving the tubule makes the filtrate saltier
- lots of water channels (aquaporins)
**the filtrate gets saltier as it moves thru the system
- the water is following the filtrate as it gets saltier
- water leaves the aquaporin by active transport
75
Ascending Loop of Henle
reabsorbs NaCl
- NaCl channels in this part but no aquaporins
thin segment = NaCl gets reabsorbed thru passive transport
thick segment = NaCl gets reabsorbed thru active transport
- needs active transport bc there's less salt so there's no gradient
**the salt leaves and moves into the interstatial fluid space
76
Distal Tubule
secretion and reabsorption
- this is the last time the body decides what to pull out and what to keep in the filtrate
- more in tune with the body
ex: if blood pressure changes and you need more salt, they would pull more salt out of the filtrate bc you need that
77
Collecting Duct
filtrate is processed into urine in the collecting duct
- a little urea is reabsorbed which increases the solute concentration so more water leaves via osmosis
- urea and water leave because water follows salt
