9. Respiration And Regulation Of The Internal Environment Flashcards
1
Q
What is partial pressure?
A
A measure of the force exerted by the individual components in a mixture of gases.
2
Q
What is total pressure?
A
The sum of all partial pressures of all the gases in a mixture.
3
Q
What is atmospheric pressure?
A
The pressure exerted by the weight of the atmosphere.
4
Q
What is the mean atmospheric pressure at sea level?
A
760 mm Hg.
101.3 kPa
5
Q
What is the partial pressure equation of atmospheric oxygen?
A
Pressure oxygen = total pressure X % Oxygen
6
Q
Is partial pressure the same as concentration?
A
No.
7
Q
When a liquid is exposed to air, what is the difference in partial pressure of a gas present in both the liquid and air?
A
It is the same because an equilibrium state is reached.
8
Q
What is the difference in oxygen solubility in water vs air?
A
Oxygen is less soluble in water than it is in air.
9
Q
Why is getting oxygen from water harder than getting it from air?
A
Water is more dense and has a higher viscosity than air.
10
Q
Respiratory surfaces are always…?
A
Moist.
11
Q
What are 2 characteristics of respiratory surfaces?
A
- Large.
- Thin.
Diffusion is faster with a large surface area and a short path to travel
12
Q
What are gills?
A
Branching organs with a high surface area, dense with capillaries, that are suspended in water for gas exchange.
13
Q
What is ventilation?
A
The process of the respiratory medium moving over the respiratory surface.
Ventilation maintains the partial pressure gradients of oxygen and carbon dioxide.
14
Q
Why do fish need to maximise their oxygen uptake?
A
There is a lower concentration of oxygen in water.
15
Q
Where do fish uptake water?
A
Fish take water in through their mouth and pass it over their gills.
16
Q
What is countercurrent exchange in fish?
A
In fish capillaries, blood and water flow in opposite directions, which drives net oxygen diffusion from the water into the blood.
17
Q
What is the enclosed respiratory system of an insect called?
A
The tracheal system.
18
Q
What is the tracheal system?
A
A network of tubes throughout an insect’s body, with air sacs located near organs that need oxygen and spiracles in the tracheal branches.
19
Q
What are spiracles?
A
External openings that allow air to flow in and out of a system.
20
Q
What is the simplified process of respiration in an insect’s body?
A
- Air enters through spiracles (external openings).
- Air moves to trachea and through tracheal branches, bringing oxygen within a short distance of all cells.
- Gas diffusion occurs through the moist epithelial lining at the end of the branches.
- Carbon dioxide leaves the body through the spiracles.
21
Q
Can insects regulate the amount of air that moves through their tracheal system?
A
Yes.
But it is complicated.
22
Q
What are lungs?
A
Specialised internal respiratory organs that are not in direct contact with the rest of the body, requiring transport of gases from unreachable cells via the circulatory system.
23
Q
What type of circulatory system has lungs?
A
Both closed and open circulatory systems.
24
Q
What is a cloaca?
A
An opening at an animal’s posterior where the digestive, reproduction, and urinary tracts meet.
Found in reptiles, avians and some other vertebrates
25
Turtles can supplement lung breathing with gas exchange known as...?
Cloacal breathing.
26
What is the larynx?
The voice box.
Vocal chords are located in the upper larynx.
27
Where is the larynx?
The upper part of the respiratory tract.
Before the trachea and after the pharynx.
28
What is the pharynx?
A muscular tube consisting of the nasopharynx, oropharynx, and laryngopharynx.
29
Where is the pharynx?
The upper respiratory tract.
At the junction where food and air cross, above the larynx.
30
What is the epiglottis?
A small moveable flap just above the larynx that prevents food and drink from entering the trachea.
31
What is the trachea?
A single tube that connects the larynx to the bronchi.
Also known as the windpipe.
32
What are the bronchi?
A pair of pipes that branch from the trachea to the lungs.
*bronchus = singlular*
33
What are the bronchioles?
The finer branches of the bronchi that transport air to and from the alveoli.
34
What are the alveoli?
Air sacs at the end of a bronchiole where gas exchange occurs.
*alveolus = singular*
35
What are 3 anatomic characteristics of alveoli?
1. Very thin walls.
2. Dense covering of capillaries to support gas exchange.
3. Lined with surfactant.
36
What is surfactant?
A surface-agent secreted by alveoli that decreases surface tension, preventing alveoli collapse.
37
What is choking?
Breathing difficulties resulting from **acute** obstruction of the airways.
38
What is the diaphragm?
A sheet of muscle that forms the bottom wall of the thoracic cavity in mammals.
39
What are 8 anatomic features passed through in respiration?
1. Nasal cavity.
2. Pharynx.
3. Epiglottis.
4. Passes larynx.
5. Trachea.
6. Bronchi.
7. Bronchioles.
8. Alveoli air sacs.
40
What is the function of the nasal cavity?
It fillters, warms and humidifies the air.
41
How many lobes does the human right lung have?
3 lobes.
Upper, middle and lower.
42
How many lobes does the human left lung have?
2 lobes.
Upper and lower.
43
Why do humans have a different number of lobes on the left and right lungs?
The left lung has to accommodate the heart.
44
What are the 4 structures that air goes through from the bronchioles to the air sacs?
1. Terminal bronchioles.
2. Respiratory bronchioles.
3. Alveoli ducts.
4. Alveoli sacs.
45
Where does deoxygenated blood enter the alveoli from?
The pulmonary artery.
46
Where does oxygenated blood leave the alveoli from?
The pulmonary vein.
47
How many spherical alveoli are in alveolar sacs?
20 to 30
48
What is breathing?
The process of ventilating the lungs through an alternation between inhalation and exhalation of air.
49
What mechanism of breathing occurs in birds?
Two cycle breathing.
50
What mechanism of breathing occurs in amphibians?
Positive pressure breathing.
51
What mechanism of breathing occurs in mammals?
Negative pressure breathing.
52
What is two cycle breathing?
- Two unidirectional cycles of inhalation and exhalation are required to pass one breath through the system.
- This ensures no mixing between the inhaled and exhaled gases
- Posterior **and** anterior air sacs on either side of the lungs are required
53
It is believed that dinosaurs had a similar respiratory system to...?
Birds.
*Two cycle breathing*
54
What is positive pressure breathing?
A method of breathing that involves using the contraction of muscles to **actively** push air into the lungs.
55
What is negative pressure breathing?
A method breathing where air is **drawn into** the lungs because of decreased pressure within the chest cavity caused by the expansion of the thoracic cavity during inhalation.
56
What direction does air flow?
From high-pressure regions to low-pressure regions.
57
Where does the double membrane in the thoracic cavity adhere?
One side adheres to the lungs.
The other side adheres to the thoracic cavity.
58
How does the thoracic double membrane influence lung capacity?
The membranes are separated by a thin coating of fluid that allows them to slide on each other, though they can't separate due to surface tension.
Thus, as the thoracic cavity expands, the membrane pulls on the lungs, and the space capacity expands.
59
What fibres allow the alveoli to expand and contact?
Elastic fibres contained in the alveoli walls.
60
What is tidal volume?
The volume of air inhaled and exhaled with a single breath when **at rest**.
61
What is vital capacity?
The maximum volume inhaled and exhaled with a single breath when at **maximum effort**.
62
What is residual volume?
The volume of air left in the lungs after a forced exhalation.
63
Breathing is an involuntary process regulated by neurons located where in the brain?
In the medulla oblongate.
64
What is the main method of feedback from the body received by the medulla oblongate?
pH of the cerebrospinal fluid.
65
What determines the pH of the CSF?
The blood pH.
Which, in turn, is determined by CO2 concentrations.
66
What happens to blood as CO2 increases?
As carbon dioxide increases, hydrogen ions increase.
This lowers pH and makes the blood more acidic.
67
What are 3 places that pH sensors are located?
1. The brain *(medulla)*.
2. The carotid arteries.
3. The aorta.
68
What does the medulla do after detecting increased carbon dioxide?
Stimulates the muscles of the rib cage and diaphragm to expand more, increasing the capacity and ventilation rate.
69
Do the partial pressures of oxygen and carbon dioxide change throughout the body?
Yes.
70
In the lungs, partial pressure favours the net diffusion of...?
Oxygen into the blood and carbon dioxide out of the blood.
*The opposite situation exists in the rest of the body.*
71
What is haemoglobin?
- The respiratory pigment of many invertebrates and most vertebrates.
- The protein responsible for carrying oxygen.
- Found in erythrocytes.
72
How many subunits does haemoglobin have?
4 haem *(heme)* subunits, each with their own Fe2+ atom at the centre.
73
Why is blood red?
The iron atoms located in each haem subunit of haemoglobin give blood its colour.
74
How many oxygen molecules can one molecule of haemoglobin bind to?
4 molecules of O2
*(One molecule of O2 per iron atom)*
75
What is myoglobin?
An oxygen-storage protein found in animal muscle cells.
It contains haem and has a higher affinity for oxygen than haemoglobin but is unable to transport oxygen around the body.
76
What 2 factors allow marine mammals to store larger amounts of oxygen?
1. Increased volume of blood per kilogram of mass.
2. Higher concentrations of myoglobin in their muscles.
77
What is hemocyanin?
A colourless copper-containijg respiratory protein that turns blue when oxygenated.
Found in the haemolymph of molluscs, arthropods and crustaceans.
78
What are conformers?
Organisms that allow their internal environment to change in response to external environment conditions.
79
What are regulators?
Organisms that maintain a stable body temperature regardless of fluctuations in the external environment.
80
What is homeostasis?
The maintenance of an internal balance or steady state even when the external environment changes significantly.
*Homeostasis in humans includes a constant body temperature around 37 degrees Celcius and a constant blood pH of about 7.4*
81
What is a negative feedback loop?
When the stimulus is opposite to the response.
The required response is the reverse of the change detected.
82
What is a positive feedback loop?
When the stimulus causes even more of the stimulus.
*Positive feedback loops do **not** promote homeostasis*
83
What are 2 examples of positive feedback loops in the human body?
1. The formation of platelets to clot a wound.
2. The stimulation of milk production when lactating.
84
What are circadian rhythms?
Intrinsic bodily functions occurring on a 24-hour cycle, often synchronised with patterns of light and darkness.
85
What is melatonin?
A hormone influencing the timing of circadian rhythms and playing a key role in sleep regulation.
86
When is melatonin normally released?
Melatonin is released into the bloodstream in response to darkness - it is released at nightime, and more is released during winter due to the reduction of sunlight hours.
87
What does light exposure at night negatively impact?
Melatonin production.
88
What is the correlation between melatonin and body temperature?
High body temperature = low concentrations of melatonin in the blood.
Low body temperature = high concentrations of melatonin in the blood.
89
What is acclimatisation?
Physiological adjustment to the changes in the external environment.
*E.g. to lower oxygen levels at higher altitudes*
90
How long do RBCs live for?
Approximately 120 days.
91
What is thermoregulation?
The process by which animals maintain their body temperature within a normal range.
92
Thermal energy can be obtained in what 2 ways?
1. Internally via metabolism.
2. Externally from the environment.
93
What is metabolism?
The process by which your body converts what you eat and drink into energy.
94
How does the human body acclimatise to low concentrations of O2?
The haemoglobin O2 holding capacity is altered in RBCs.
Haemoglobin releases oxygen more easily due to the low availability of oxygen.
95
What are animals with a constant body temperature?
Homeotherms.
96
What are animals with a body temperature that fluctuates?
Poikilotherms.
97
Are all endotherms also homeotherms?
No.
And not all ectotherms are poikilotherms either.
98
What are the 4 processes of thermoregulation?
1. Radiation.
2. Evaporation.
3. Convection.
4. Conduction.
99
What is radiation thermoregulation?
Absorbing thermal heat from sun or fire.
100
What is evaporation thermoregulation?
Losing heat from the body as molecules of gas.
*E.g. sweating*
101
What is convection thermoregulation?
Thermal energy transferral through air moving past the body.
*E.g. warm wind*
102
What is conduction thermoregulation?
Direct exchange of thermal energy from one object in contact with another.
*E.g. laying on a warm rock*
103
What is torpor?
A state of decreased activity and metabolism that conserves energy during environmental extremes.
104
What 2 features help penguins to have unfrozen feet despite lacking insulation or fur and having a broad surface area in contact with ice?
1. Hormones stimulate vasoconstriction in the cold, reducing bloodflow subsequent heat loss.
2. Countercurrent heat exchange.
105
What is insulation in an animal?
Something that reduces the flow of heat between an animal and its environment.
*E.g. hair, feathers, adipose tissue, and oily substances*
106
What are 6 adaptations for thermal regulation?
1. Vasoconstriction.
2. Vasodilation.
3. Countercurrent heat exchange.
4. Evaporative heat loss.
5. Behavioural responses.
6. Metabolic heat production.
107
What are 2 metabolic heat production processes?
1. Shivering.
2. Brown fat activation.
108
How does countercurrent heat exchange work?
The close contact between veins and arteries causes the heat flow to literally cool the arterial blood before it reaches the extremities and warm the returning blood before it reaches the heart.
109
What is vasoconstriction thermal regulation?
Blood vessels narrow to reduce bloodflow and minimise heat loss from tissues.
110
What is vasodilation thermal regulation?
Blood vessels can widen to increase blood flow and increase heat loss.
*The reason people get red-faced after exercise*
111
Many species adjust to seasonal variations in temperature by growing...?
Thick coats of fur in winter and shedding it in summer.
112
What part of the brain controls thermoregulationnand the circadian clock (in mammals)?
The hypothalamus.
113
When the hypothalamus detects temperatures above the normal range...?
It promotes cooling by triggering vasodilation, sweating, or panting.
114
When the hypothalamus detects temperature below the normal range...?
It promotes heating by triggering vasoconstriction.
115
What is a fever?
A raised body temperature that speeds up how cells work *(including immune cells)* while making it harder for bacteria and viruses to thrive in an animal's body.
116
What is bioenergetics?
The overall flow and transformation of energy in an animal - related to the nutritional needs based on an animal's size, activity, and environment.
117
What is digestion?
The complex process of turning food into nutrients, which the body uses for energy, growth, and cell repair.
118
What is cellular respiration?
The process of organisms using oxygen to break down food molecules to get chemical energy for cell functions.
*Carbon dioxide and water are discarded as waste products, and heat loss occurs.*
119
What is metabolic rate?
The sum of the energy an animal uses in a given time.
Nearly all chemical energy used in cellular respiration eventually appears as heat; metabolic rate can be measured by monitoring heat loss.
120
What is Basal metabolic rate (BMR)?
The metabolic rate of a non-growing **endotherm** that is at rest, not digesting and not experiencing stress.
121
What is Standard metabolic rate (SMR)?
The metabolic rate of a fasting, non-stressed **ectotherm** at rest.
122
Metabolic rate is proportional to...?
Body mass.
As the mass of the animal increases, so does it's total BMR.
However, this change is **not** linear.
123
The energy to maintain each gram of body mass is related to...?
Inversely related to body size.
The smaller the animal, the higher the metabolic rate per gram.
124
As body size increases, energy per gram of tissue decreased, but...?
An even larger faction of body tissue is required for exchange, structural support and locomotion.
125
In regards to metabolic rate (BMR), the smaller animal...?
Has an overall smaller metabolic rate due to it's decreased body mass.
But it has a higher metabolic rate proportionately to its size.
