45 Gas Exchange And Circulation

Front 1

Cells must obtain oxygen and expel carbon dioxide continuously

Back 1

To support ATP production by mitochondria

Front 2

Gas exchange involves four steps

Back 2

Ventilation

Gas exchange

Circulation

Cellular respiration

Front 3

What gases make up the atmospere

Back 3

Argon( 0.93%)

Carbon dioxide (0.03%)

Oxygen (21%)

Nitrogen (78%)

Front 4

Gas exchange between the environment and cells

Back 4

Is based on diffusion

Front 5

Oxygen is

Back 5

High in the environment and low in tissues

Front 6

Carbon is

Back 6

High in tissues and low in the environment

Front 7

Oxygen tends to move while carbon moves

Back 7

Oxygen : environment to tissue

Carbon: tissues to the environment

Front 8

Partial pressure

Back 8

is the pressure of a particular in a mixture of gases

Front 9

To calculate the partial pressure of a particular gas

Back 9

Multiple the fractional composition of that gas by the total pressure exerted by the entire mixture (Daltons law)

Front 10

The partial pressure of oxygen

Back 10

Falls with increasing elevation

Sea level (P O2=160mm Hg)

Front 11

Sea level barometric pressure is 760 mmHg. Since oxygen is 21% of air, the partial pressure of oxygen is

Back 11

0.21×760=160mmHg

Front 12

In both air and water, oxygen and carbon dioxide move from regions of

Back 12

High partial pressure to regions of low partial pressure

Front 13

The diffusion of the tow gasses is dependent upon the partial pressure gradient

Back 13

At the top of MY Everest the partial pressure of oxygen is low, and thus it is harder to take needed oxygen

Front 14

Water has less available oxygen than air

Back 14

To extract a given amount of oxygen, an aquatic animal has to process 30 times more water than the amount of air a terrestrial animal breathes

Front 15

Water is about a thousand times denser than air and flows less easily

Back 15

Water breathers have to expend more energy to ventilated their respiratory surfaces than do air breathers

Front 16

Deep water

Back 16

Relatively small surface area, expect O2 and CO2 gradient with little at the bottum

Front 17

Shallow water

Back 17

Relatively large surface area, most of water will have O2 and CO2

Front 18

Oxyg3n and carbon dioxide diffuse into water from the atmosphere, but the amount of gas that dissolves depends on several factors:

Back 18

1) the solubility of the gas in water

2) the temperature of the water

3) the presence of the other solutes

4) the partial pressure of the gas in contact with the water

Front 19

Moving, white water has

Back 19

High oxygen partial pressure

Front 20

Stagnant water has

Back 20

Low oxygen partial pressure.

Front 21

Diffusion occurs across the

Back 21

Medium gas exchanger epithelium

Front 22

This is the interface between

Back 22

Water and Gill (aquatic gas exchange organ) or

Air and lung ( terrestrial gas exchange Organ)

Front 23

Ficks law identify traits that allow animals to

Back 23

Maximize the rate at which oxygen and carbon dioxide diffuse across surfaces

Front 24

Ficks law states that all gases including oxygen and carbon dioxide

Back 24

Diffuse in the largest amounts when three conditions are met.

1) The surface area for gas exchange is large

2) the respiratory surface is extremely thin 3) the partial pressure gradient of the gas across the surface is large

Front 25

Diffusion constant

Back 25

Depends on solubility of gas and temperature

Front 26

Rate of diffusion equals

Back 26

K x a x (P2 - P1) / d

K is diffusion constant

A is area for gas exchange

P2 - P1 is difference in partial pressure of gas on either side of barrier to diffusion

D is distance (thickness of barrier to diffusion)

Front 27

Gills

Back 27

Are outgrowths of the body surface or throat, used for gas exchange in aquatic animals

Front 28

Gill's present

Back 28

An extremely large surface area for oxygen to diffuse across and extremely thin epithelium

Front 29

Among invertebrate the structure of gills is extremely diverse Gill's Canby external or internal

Back 29

Fish gills are located on both sides of the head In teleosts consisting of four arches

Front 30

Two basic strategies and fish for ventilating gills

Back 30

Ram Jet ventilation and Buccal pumping

Front 31

Extreme Ram jet ventilators

Back 31

Some species of sharks. They will suffocate if they stop swimming

Front 32

Extreme Buccal Pumpers

Back 32

Sit and wait predators

Front 33

Counter-current flow

Back 33

Scene in fish gills

Front 34

Concurrent flow

Back 34

Not seen in fish gills water flow and blood flow move in the same direction

Front 35

Insects have air filled tubes called

Back 35

Trachea

Front 36

Trachea open to the outside through pores called

Back 36

Spiracles. Air moves into the trachea and then by diffusion into the cells. And small insects, this is sufficient to exchange gases

Front 37

Hypothesis, air moves through the tracheal system faster during physical activity

Prediction, flying will increase ventilation of tracheal systems causing increase in P O2 in Wing muscle

Back 37

Conclusion, muscular contractions may help ventilate the tracheal system in at least some insects

Front 38

And larger species, trachea alternately open and close as the wing muscles around them contract and relax

Back 38

As a result, the volume of the tracheal system changes

as the volume changes, so does the pressure.

Pressure and volume are inversely related. The movement of gases is also aided by larger trachea

Front 39

Model of oxygen delivery during flight

Back 39

Air flows in as muscles relax expanding the trachea moving the wing up. The muscle contracts and air goes out the tracheas are squeezed air is pushed out and the muscle relaxes moving the wing down

Front 40

Tracheae dilate when

Back 40

Muscles relax

Front 41

Tracheae compress when

Back 41

Muscles contract

Front 42

In terrestrial animals

Back 42

Air enters the body through the mouth and nose

Front 43

The trachea carries inhaled air too narrow tubes called

Back 43

Bronchi

Front 44

The bronchi Branch off into even narrower tubes called

Back 44

Bronchioles

Front 45

The Oregon for gas exchange is the

Back 45

Belong and causes the bronchioles and portions of the bronchi

Front 46

Airway into the lung

Back 46

The trachea leads to the bronchi which have bronchioles inside the lung

Front 47

In frogs and other amphibians

Back 47

The long is a simple Sac lined with blood vessels

Front 48

Mammalian lungs are divided into tiny sacs called alveoli, which greatly increase the surface area for gas exchange

Back 48

Humans have approximately 150 million alveoli per lung

Front 49

The epithelium of alveolus

Back 49

Have extremely thin walls this improves the speed of diffusion

Front 50

The capacity of the human lung

Back 50

About 450 mL of air move into an out of the lungs in an average breath. Only about two-thirds of this volume actually participates in gas exchange, however, because 150ml of the air occupies Dead Space portions of the air passages, such as the trachea and the bronchi, that do not have a respiratory surface

Front 51

There are two mechanisms for pumping air

Back 51

1. Positive pressure ventilation, used by frogs

2. Negative-pressure ventilation used by humans and other mammals

Front 52

Lungs expand and contract in response to change in pressure inside the chest cavity

Back 52

Inhalation: pressure becomes more negative and the diaphragm goes down exhalation: Pressure becomes less negative and the diaphragm moves up

Front 53

One Way air flow through avian lung

Back 53

Step 1 posterior air sacs fill with outside air.

Step 2 lung fills with air from the posterior sacs

step 3 anterior air sacs fill with air from the lungs

step 4 anterior air sacs empty

Front 54

At rest, the mammalian rate of breathing is established by the medullary respiratory Center, an area at the base of the brain

Back 54

The medullary respiratory Center stimulates the rib and diagram muscles to expand and contract

Front 55

Exercise causes muscle cells use more oxygen and give off more carbon dioxide, changing the partial pressure in the blood the excess carbon dioxide causes blood to become slightly more acidic for moment

Back 55

The sends messages to the neurological system to increase breathing rate which means more oxygen in and more carbon dioxide released

Front 56

Increase carbon dioxide, CO2, reacts with water in the blood in cerebrospinal fluid (CSF), to form carbonate acid, H2CO3, which quickly disassociate into a hydrogen ion H+ in a bicarbonate ion, HCO3-

Back 56

CO2 + H2O <--> H2 CO3 <--> H + HCO3Z

The release of the hydrogen ions lowers the blood and CSF pH, which is sense by specialized neurons, leading to the medullary respiratory Center and increasing the breathing rate, which Returns the partial pressures of these two gases at resting level.

Front 57

Blood has many functions

Back 57

Transport oxygen and carbon dioxide transport nutrients to cells from the digestive system

conveys hormones to Target tissues and organs

deliver cells of the immune system distributes Heat

the water portion is often referred to as extracellular Matrix or simply the plasma

Front 58

Cellular components of the blood

Back 58

1. Platelets are cell fragments that minimize blood loss.

2. White blood cells wbcs are parts of the immune system.

3. Red blood cells rbc's transport oxygen from the lungs to body tissues, and participate in transporting carbon dioxide from tissues to lungs. In humans, red blood cells make up 99.9% of the formed elements.

Front 59

Each hemoglobin molecule can

Back 59

Find up to four molecules of oxygen. 98.5% of oxygen binds to hemoglobin in red blood cells. 1.5% of oxygen dissolves in the blood plasma and the rate of unloading depends on the partial pressure of oxygen and the tissue.

Front 60

Blood leaving human lungs has a P O2 greater than that of molecules and other tissues

Back 60

This difference creates the diffusion gradient that unloads O2 from hemoglobin to the tissues

Front 61

The oxygen hemoglobin equilibrium curve or the oxygen dissociation curve, plots the percentage saturation of hemoglobin in RBC vs the P O2 in blood within tissue

Back 61

The curve is sigmoid all, or s-shaped, which is significant due to The Binding of each successive oxygen molecule. This represents a conformational change in the protein, which AIDS in the addition of more oxygen this phenomenon is called Cooperative binding

Front 62

Why is cooperative binding important

Back 62

Cooperative binding makes hemoglobin exquisitely sensitive to changes in the partial pressure of oxygen of tissues. In other words, in response to a relatively small change in partial pressure oxygen there is a relatively large change in the percentage saturation of hemoglobin.

Front 63

With Cooperative binding

Back 63

Large amounts of o2 are delivered to resting and exercising tissues

Front 64

Without Cooperative binding

Back 64

Smaller amounts of oxygen would be delivered to resting and exercising tissues

Front 65

Hemoglobin is sensitive to changes in the ph and temperature

Back 65

Decreases in PH and increases in temperature alter hemoglobins confirmation such that it is more likely to release oxygen at all values of partial pressure of oxygen. Note, a conformational change means a change in the shape of a molecule

Front 66

Bohr shift

Back 66

The Bohr shift makes hemoglobin more likely to release oxygen during exercise and which partial pressure of carbon dioxide is high, pH is low, and tissues are under oxygen stress

Front 67

CO2 that is produced by cellular respiration enters the blood and RBC, red blood cells

Back 67

Where it is quickly converted to bicarbonate ions and protons in a reaction catalyzed by the enzyme Carbonic anhydrase

Front 68

Carbonic anhydrase catalyzes the formation of carbonic acid from carbon dioxide in water

Back 68

CO2 that diffuses into red blood cells is quickly converted to bicarbonate ions and protons. Most CO2 is transported in blood specifically and plasma, and the form of bicarbonate ion, hco3

Front 69

Carbonic anhydrase activity and red blood cells is important for two reasons

Back 69

1. The protons produced by the Carbonic anhydrase reaction induced abortion, which makes hemoglobin more likely to release oxygen.

2. The partial pressure CO2 in blood drops when CO2 is converted to bicarbonate maintaining a strong partial pressure gradient favoring the entry of CO2 into red blood cells

Front 70

When blood returns to the lungs hemoglobin releases protons which combined with bicarbonate to form CO2

Back 70

Which then diffuses into the alveoli and is exhaled from the lungs

Front 71

Hemoglobin picks up what during inhalation

Back 71

O2

Front 72

In the open system, the hemolymph is pumped throughout the body in open vessels

Back 72

The hemolymph comes in direct contact with the body tissues,

the open system is characteristic of invertebrates,

the hemolymph is pumped by an organ called the heart.

Front 73

Blood vessels are classified as

Back 73

Arteries, capillaries, veins

Front 74

Arteries

Back 74

Are tough, thick walled vessels that take blood away from the heart under high pressure, small arteries are called are called arterioles

Front 75

Capillaries

Back 75

Are the smallest vessels. Their walls are just one cell thick, allowing gases and other molecules to exchange with tissues and networks called capillary beds

Front 76

Veins

Back 76

Are vessels that return blood to the heart under low pressure. Small veins are called venules

Front 77

Arteries and veins

Back 77

Arteries and veins have different structures they are made of the same Fabrice muscle elastic and endothelium tissues but arteries are much thicker this allows them to tolerate very high pressures

Front 78

Capillaries are made of a nucleus endothelial all cells basement membrane

Back 78

They also have variable with gaps between endothelial cells that allow some plasma to escape because they are only one cell layer across only very small hydrostatic pressures are tolerated

Front 79

The area between cells is called the interstitial space

Back 79

The food that leaks into the interstitial space is called the interstitial fluid

Front 80

Interstitial fluid builds up because of two forces

Back 80

1. There is an outward directed hydrostatic force in capillaries, created by the pressure on blood generated by the heart.

2. There is an inward directed osmotic force in capillaries, created by the higher concentration of solutes in the blood plasma than in the interstitial space

Front 81

Animals with closed circulatory systems, the heart contains at least two Chambers

Back 81

1. The Atrium receives blood returning from circulation.

2. The ventricle generates Force to propel the blood through the system

Front 82

Hearts need

Back 82

A pressurizing element and at least one valve to prevent backflow. Vein leads to the atrium which leads to The ventricle which leads to the artery

Front 83

The pulmonary circulation

Back 83

Is a lower pressure circuit to and from the lungs

Front 84

The systemic circulation

Back 84

Is a higher pressure circuit to and from the rest of the body

Front 85

Process, pulmonary circulation

Back 85

First blood enters right atrium on return from body next blood enters the right ventricle and then blood is pumped to the lungs from the right ventricle

Front 86

Process systemic circulation

Back 86

Once the blood has gone through the pulmonary circulation the blood returns to the left atrium from Lunds then the blood enters left ventricle last leave the blood is pumped to body from left ventricle and it goes back to the pulmonary circulation

Front 87

The specific sequence of the flow of blood in the human heart

Back 87

1. Blood returns from the body to the right atrium.

2. Blood enters the right ventricle through the right atrioventricular(AV) valve.

3. Blood is pumped through the pulmonary valve, into the pulmonary artery, and to the lungs .

4. Blood returns from the lungs, via the pulmonary veins, to the left atrium.

5. Blood enters the left ventricle through the left AV valve .

6. Blood is pumped through the aortic valve, into the aorta, and to the body.

Front 88

Signals from the sinoatrial SA, node Ensure

Back 88

That the Atria contract simultaneously, then relax

Front 89

Signals from the atrioventricular AV, node Ensure

Back 89

That the ventricles contract while the Atria are relaxed.

The contraction phase is the systole.

The relaxation phase is the diastole

Front 90

Process electrical activation of the heart

Back 90

1. Signal originates at SA node.

2. Signal spreads over Atria, Atria contracts. 3. Signal delays at AV node.

4. Signal spreads down conducting fibers to bottom of ventricles. Ventricles contract. 5. Ventricles relax

Front 91

The contraction phase of the Atria and the ventricles, called the systole, is coordinated with the relaxation phase, or diastole

Back 91

The cardiac cycle consists of one complete systole and one complete diastole

Front 92

Systolic blood pressure

Back 92

Is blood pressure measured in the systemic atrial circulation at the peak of ventricular ejection into the aorta

Front 93

Diastolic blood pressure

Back 93

Is blood pressure measured just before ventricular ejection

Front 94

Diastole

Back 94

The heart is relaxed and filling

Front 95

Systole

Back 95

The heart is contracted and ejecting

Front 96

People with blood pressure is consistently higher than 140/90 mmhg have high blood pressure, or hypertension

Back 96

A serious health concern because it can lead to a variety of circulatory system defects period abnormally high blood pressure puts mechanical stress on arteries, if the walls of the artery fail, the individual may experience heart attack, stroke, kidney failure, and burst or dilated blood vessels

Front 97

Blood pressure

Back 97

Is the force that blood exerts on the walls of arteries, capillaries, and veins

Front 98

Blood pressure drops dramatically as blood moves through the capillaries, because the total cross-sectional area of blood vessels in the circulatory system increases greatly

Back 98

The drop in blood pressure decreases the rate of blood flow to allow sufficient time for gases, nutrients, and waste to diffuse between tissues and blood in the capillaries

Front 99

Blood movement is carefully regulated at an array of points throughout the circulatory system

Back 99

The nervous system, along with certain chemical Messengers in the circulation, can accurately control blood flow to various tissues by Contracting or relaxing the arteriolar sphincters

Front 100

Decreases in blood pressure elicits a powerful homeostatic response

Back 100

Falling blood pressure is detected by baroreceptors in the walls of the heart and the major arteries

Front 101

Blood shunting is critical

Back 101

Because vascular volume is much greater than blood volume. If there is too much vasodilation blood pressure drops to zero

Front 102

Why do you feel faint when you stand up quickly

Back 102

Shunting takes time and gravity drains blood from brain and less time

Front 103

Oxygen will move from what to what

Back 103

B. The environment, the tissues.

Front 104

Based on water temperature differences you'd expect tropical fish to have

Back 104

A. More guilt issues surface area.

Front 105

A large difference in partial pressure between gases will blank the rate of diffusion

Back 105

C. Increase.