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MCAT Bio > Bio #6 > Flashcards

Bio #6 Flashcards

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1
Q

the right lung has _____ lobes while the left lung has ___ lobes

A

3

2

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2
Q

anatomy: ribs make up the ______, diaphragm makes up the _____

A

walls
floor

whole room is thorax

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3
Q

filters in the nose

A

nose hairs: large particles

nose mucus: small molecules

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4
Q

bronchus vs. bronchi

A

bronchus: 1
bronchi: >1

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5
Q

alveoli vs. alveolus

A

alveoli: >1
alveolus: 1

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6
Q

diaphragm contracts during _____

A

inhalation

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7
Q

inhaling vs. exhaling

A

volume increase, diaphragm contracts, alveoli stretch open

decrease volume, diaphragm relaxes, alveoli recoil

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8
Q

breathing heavily can aid with ______

A

thermoregulation

breathing in cooler air than you are breathing out (dogs panting)

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9
Q

thoracic cavity

A

location of the lungs that is designed to perform breathing

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10
Q

nares

A

nostrils, external part of the nose where air enters the respiratory tract

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11
Q

vibrissae

A

mucous membranes and nasal hairs that are located in the nasal cavity and filter air.

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12
Q

pharynx

A

behind the nasal cavity at the back of the mouth, common pathway for air destined for the lungs and food destined for the esophagus.

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13
Q

larynx

A

: located below the pharynx (only pathway for air)
o The opening of the larynx, the glottis, which is covered by the epiglottis, keeps food out of the larynx during swallowing.
o Contains two vocal cords which are controlled by skeletal muscle and cartilage.

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14
Q

trachea

A

after the larynx

start of the lower respiratory tract

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15
Q

bronchi

A

left and right after the trachea

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16
Q

bronchioles

A

divisions of bronchi

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17
Q

alveoli

A

gas exchange occurs

o Branching and minute size allow for large surface area for gas exchange.

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18
Q

surfactant

A

coats each alveolus, a detergent which lowers surface tension and prevents the alveolus from collapsing on itself.

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19
Q

the vocal cords are located in the ____-

A

larynx

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20
Q

what pathway is shared by the digestive tract and respiratory tract in the back of the mouth?

A

pharynx

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21
Q

Trachea and Bronchi contain _____ to catch stuff that made it past the mucous membranes of the nose and mouth.

A

ciliated epithelial cells

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22
Q

what is the pathway that air travels into the body

A

Respiratory Tract: Nares  nasal cavity  pharynx  larynx  trachea  bronchi (in lungs)  bronchioles  alveoli

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23
Q

along with the lungs in the thoracic cavity is the _____

A

heart

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24
Q

pleurae

A

membranes that surround each lung (visceral pleura, intrapleural space, parietal pleura)
 The intrapleural space contains a thin layer of fluid which lubricates the other surfaces (it is a potential space, can be filled which is bad).
 Pressure differentials across the pleura drive breathing.

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25
Q

interior to exterior of lungs

A

o Lungs (interior)  visceral pleura  intrapleural space  parietal pleura  chest wall (exterior)

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26
Q

diaphragm

A

skeletal muscle that helps to create negative pressure for lung expansion. It is a thin, muscular structure that divides the thoracic (chest) cavity from the abdominal cavity. Under somatic control.
o Can contract, which makes it flatter and wider.

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27
Q

contracting the diaphragm makes it ____

A

flatter and wider

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28
Q

external intercostal muscles

A

one of the layers of muscles between the ribs

expand the thoracic cavity

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29
Q

breathing

A

• The diaphragm and external intercostal muscles (one of the layers of muscles between the ribs) expand the thoracic cavity.
• Intrathoracic volume: volume of the chest cavity
• Diaphragm flattens  chest wall expands  intrathoracic volume increases
• Negative-pressure breathing: the intrapleural space volume increases, decreasing its pressure. It is lower pressure than in the lungs so the lungs will expand into this space. The pressure in the lungs then drops and air will be sucked in from a higher-pressure environment (the outside world).
• Exhalation: relies on the relaxation of the diaphragm and external intercostal muscles to reverse the process.
• Internal intercostal muscles: pull the rib cage down and decrease the volume of the thoracic cavity.
o Expiration in calm states is specifically due to elastic recoil of the lungs.
• Avoidance of collapse during exhalation: due to indirect connection of the lungs to the chest wall and for alveoli it’s due to surfactant.

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30
Q

intrathoracic volume

A

volume of the chest cavity

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31
Q

what happens when you breath in

A

• Diaphragm flattens  chest wall expands  intrathoracic volume increases

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32
Q

negative pressure breathing

A

the intrapleural space volume increases, decreasing its pressure. It is lower pressure than in the lungs so the lungs will expand into this space. The pressure in the lungs then drops and air will be sucked in from a higher-pressure environment (the outside world).

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33
Q

internal intercostal muscles

A

one of the layers of muscles between the ribs

pull the rib cage down and decrease the volume of the thoracic cavity.
o Expiration in calm states is specifically due to elastic recoil of the lungs.

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34
Q

spirometer

A

used to measure lung capacity and volume.
o Cannot measure the amount of air remaining in the lungs after complete exhalation (so it cannot measure residual volume or total lung capacity)

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35
Q

Total lung capacity (TLC)

A

the maximum volume of air in the lungs when one inhales completely; usually around 6-7 L

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36
Q

Residual volume (RV)

A

the volume of air remaining in the lungs when one exhales completely

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37
Q

Vital capacity (VC)

A

the difference between the minimum and maximum volume of air in the lungs (TLC-RV)

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38
Q

Tidal volume (TV)

A

the volume of air inhaled or exhaled in a normal breath

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39
Q

Expiratory reserve volume (ERV)

A

the volume of additional air that can be forcibly exhaled after a normal exhalation

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40
Q

Inspiratory reserve volume (IRV)

A

the volume of additional air that can be forcible inhaled after a normal inhalation.

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41
Q

what happens with a stiff lung

A

o Decrease total lung capacity and inspiratory reserve volume
o Decrease residual volume

42
Q

what happens when decreased recoil of lung tissue

A

o Increased total lung capacity
o Decreased gas exchange
o Increase residual volume

43
Q

regulation of breathing

A

• Ventilation center: collection of neurons in the medulla oblongata that controls ventilation
o These neurons contain chemoreceptors that are sensitive to both CO2 and oxygen (mostly CO2)
o Hypercarbia or hypercapnia: high concentration of CO2 in the blood  respiratory rate increases
• If blood CO2 is too low, the body slows breathing, slows the respiratory rate.

44
Q

ventilation center

A

• Ventilation center: collection of neurons in the medulla oblongata that controls ventilation
o These neurons contain chemoreceptors that are sensitive to both CO2 and oxygen (mostly CO2)
o Hypercarbia or hypercapnia: high concentration of CO2 in the blood  respiratory rate increases

45
Q

hypercarbia or hypercapnia

A

too much CO2 in the blood, detected by the medulla oblongata

46
Q

the lungs are involved in what four functions of the body

A

breathing, thermoregulation, controlling blood pH, and serve an immune function.

47
Q

gas exchange

A

• Each alveolus is surrounded by capillaries which transport oxygenated and deoxygenated blood to and from the heart.
• Pulmonary arteries: location where deoxygenated blood exits from the right ventricle of the heart.
• Pulmonary veins: location where oxygenated blood enters the left atrium of the heart
• Gradient allows for gas exchange between the lungs and blood.
• O2 goes from the alveoli to the pulmonary capillaries where it binds hemoglobin for transport. CO2 goes from the capillaries to the alveoli for expiration.
• Hypoxia: tissue deprived of oxygen.
• High altitude results in:
o Lower oxygen levels so faster breathing
o Binding dynamics of hemoglobin change (normally in low CO2, binding to O2 would be tighter so this must be countered)
o Short term: body makes more red blood cells to ensure delivery of O2. Long term: body develops more blood vessels (vascularization)
• No gas exchange can occur if mucus has built up or if there are a lot of inflammatory cells.

48
Q

pulmonary arteries

A

location where deoxygenated blood exits from the right ventricle of the heart.

49
Q

pulmonary veins

A

: location where oxygenated blood enters the left atrium of the heart

50
Q

a _____ allows for gas exchange between the lungs and the blood

A

gradient

51
Q

a _____ allows for gas exchange between the lungs and the blood

A

gradient

52
Q

hypoxia

A

tissue deprived of oxygen.

53
Q

what happens between the alveoli and the capillaries

A

• O2 goes from the alveoli to the pulmonary capillaries where it binds hemoglobin for transport. CO2 goes from the capillaries to the alveoli for expiration.

54
Q

what happens at high altitude

A

o Lower oxygen levels so faster breathing
o Binding dynamics of hemoglobin change (normally in low CO2, binding to O2 would be tighter so this must be countered and allow for release of O2)
o Short term: body makes more red blood cells to ensure delivery of O2. Long term: body develops more blood vessels (vascularization) to deliver oxygen

55
Q

less gas exchange can occur if ____

A

• No gas exchange can occur if mucus has built up or if there are a lot of inflammatory cells.

56
Q

thermoregulation

A

the regulation of body temperature

57
Q

Vasodilation and Vasoconstriction

A

widening or constricting of blood vessels. As blood vessels expand, more blood can pass through and more thermal energy is dissipated and vice versa.
o Nasal and tracheal capillaries are most frequently used for this.

58
Q

panting

A

transfer of heat to the environment through evaporation of water in mucous secretions.

59
Q

immune function

A

Immune Function
• The first line of defense is the nasal cavity: small hairs called vibrissae trap invaders. The nasal cavity also contains lysozyme which attacks gram-positive bacteria.
• Mucociliary escalator: mucus lines the internal airways. Mucus traps invaders and underlying cilia propel the mucus up the respiratory tract to the oral cavity  swallowed or expelled.
• The lungs, especially alveoli, contain macrophages: engulf and digest pathogens and signal to the immune system.
• Also contain IgA antibodies
• Mast cells: have pre-formed antibodies on their surface. When correct substance attaches, releases chemicals that initiate an immune response  also allergies

60
Q

mucociliary escalator

A

mucus lines the internal airways. Mucus traps invaders and underlying cilia propel the mucus up the respiratory tract to the oral cavity  swallowed or expelled.

61
Q

macrophages in lungs

A

macrophages: engulf and digest pathogens and signal to the immune system.

62
Q

mast cells

A

have pre-formed antibodies on their surface. When correct substance attaches, releases chemicals that initiate an immune response  also cause allergies

63
Q

acidemia

A

pH is lower and hydrogen ion concentration is higher
 Increase respiratory rate if increase in H+ or CO2.
• Blowing off more CO2 shifts the buffer to the left which reduces the amount of H+ in the system.

64
Q

alkalemia

A

pH is higher

 Lower respiratory rate to mitigate this.

65
Q

the _____ can also compensate for alkalemia but it takes awhile

A

kidneys

66
Q

fibrosis

A

increased scar tissue

67
Q

hypertension

A

high blood pressure

68
Q

what roles do the nose and mouth play during inhalation?

A

they remove dirt and particulate matter from the air before warming and humidifying it before it reaches the lungs.

69
Q

what happens to air in the nasal cavity?

A

it is filtered by mucous membranes and nasal hairs (vibrissae)

70
Q

the bronchi and trachea contain _______ to catch material that has made it past the mucous membranes in the nose and mouth

A

ciliated epithelial cells

71
Q

the branching and minute size of the alveoli allow for an exceptionally large ______ for gas exchange

A

surface area

72
Q

why does the left lung have an indent?

A

it is due to the position of the heart in the thoracic cavity

73
Q

the diaphragm divides the ____ cavity from the ____ cavity

A

thoracic cavity from the abdominal cavity

74
Q

what is used to expand the thoracic cavity?

A

diaphragm and external intercostal muscles

75
Q

what is the ideal gas law that dictates negative pressure breathing?

A

Boyle’s Law: P1V1=P2V2

76
Q

during inhalation, the diaphragm ______ which means it _____

A

contracts

flattens

77
Q

how can exhalation be increased

A

by using the internal intercostal and abdominal muscles to pull the rib cage down and push air out

78
Q

compare the internal intercostal muscles and the external intercostal muscles

A

external intercostal muscles: inhalation

internal intercostal muscles: exhalation

79
Q

what part of the brain controls rhythmic breathing

A

medulla oblongata

80
Q

breathing is triggered by _______ that are primarily sensitive to _______

A

chemoreceptors

carbon dioxide

81
Q

what is it called when there is excess carbon dioxide in the blood? Too little oxygen?

A

hypercarbia or hypercapnia

hypoxemia

82
Q

what muscles are used during inhalation and exhalation?

A

inhalation: diaphragm and external intercostal muscles
(labored breathing also uses muscles in the neck, back, and chest)
exhalation: recoil of the above muscles as well as for labored exhalation the abdominal muscles and internal intercostal muscles

83
Q

to raise CO2 levels in the blood, the brain ______ the respiratory rate

A

slows

84
Q

what are the many functions of the lungs

A

respiration
thermoregulation
immune function
control of blood pH

85
Q

the capillaries bring _____ from the _____ where it is dropped off at the alveoli. The alveoli supply ______ which returns to the heart via the _______

A

deoxygenated blood, pulmonary artery

oxygenated blood, pulmonary vein

86
Q

what are some causes of hypoxia?

A

fibrosis or scarring of the membrane between the alveolus and the capillary
limitation of ventilation (gas flow) or perfusion (blood flow)

87
Q

is there any energy required for gas transfer in the lungs?

A

no, because of the concentration gradient.

88
Q

how do vasodilation and vasoconstriction contribute to thermoregulation?

A

vasodilation: more blood flow, more loss of thermal energy
vasoconstriction: less blood flow, less loss of thermal energy

89
Q

in addition to vasodilation, how does the respiratory system lose heat

A

mucous secretions (panting for dogs)

90
Q

the lungs are highly ____

A

vascular

91
Q

antibodies from _____ initiate allergic reactions in which ____

A

mast cells

inflammatory chemicals are produced

92
Q

draw the bicarbonate buffer system

A

CO2 + H2O <=> H2CO3 <=> H+ + HCO3-

93
Q

what is it called when the pH is too low in the blood?

A

acidemia

94
Q

what triggers in increases respiration due to pH?

A

chemosensors just outside the blood brain barrier sense the high H+ concentration and respiratory centers in the brain (medulla oblongata) sense the high CO2 concentrations

95
Q

what is it called when the blood is too basic

A

alkalemia

96
Q

how thick is the membrane between alveoli and pulmonary capillaries?

A

one cell thick

97
Q

______ in the nasal cavity and saliva attacks ____ of ____ bacteria

A

lysozyme
peptidoglycan walls
gram positive

98
Q

what role does the residual volume play?

A

it prevents the alveoli from collapsing

99
Q

the interpleural space is a ______ space

A

potential

100
Q

mucus and liquid completely _______ air exchange

A

eliminates/prevents

MCAT Bio (12 decks)

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