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EXCI 358 > Final > Flashcards

Final Flashcards

1
Q

Pulmonary ventilation

A

the process of moving and exchanging ambient air with the lungs.

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2
Q

Air moving from the nose and the mouth flows into the conductive portions of the ventilatory system where it adjusts to body temperature and is _____ and _______ as it travels through to the _________

A

filtered and humidified as it travels through to the trachea

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3
Q

Bronchi subdivide into _______ that conduct inspired air through a winding, narrow route until it eventually mixes with existing air in the _____________

A

Bronchi subdivide into bronchioles that conduct inspired air through a winding, narrow route until it eventually mixes with existing air in the alveolar ducts

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4
Q

What does the pulmonary artery do

A

Pulmonary artery: carried deoxygenated blood from the heart to the lungs

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5
Q

What does the pulmonary vein do

A

carried oxygenated blood from the lungs to the heart

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6
Q

At rest, a single red blood cell remains in the pulmonary capillary for about ______ seconds as it travels past two to three individual alveoli.

A

At rest, a single red blood cell remains in the pulmonary capillary for about 0.5 to 1.0 seconds as it travels past two to three individual alveoli.

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7
Q

The lungs contain more than ________ alveoli

A

The lungs contain more than 600 million alveoli

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8
Q

The alveoli provide the surface of gas exchange between ?

A

The alveoli provide the surface of gas exchange between lung tissue and the blood

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9
Q

What facilitates rapid exchange of respiratory gases

A

Gas diffuses across the extremely thin barrier of the alveolar and capillary cells; the diffusion distance remains relatively constant throughout varying levels of exercise

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10
Q

Each minute, at rest, approximately ? mL of O2 leaves the alveoli and enters the blood, and ? mL of CO2 diffuses in the opposite direction

A

Each minute, at rest, approximately 250 mL of O2 leaves the alveoli and enters the blood, and 200 mL of CO2 diffuses in the opposite direction

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11
Q

When an endurance athletes exercises, nearly __________ times this quantity of O2 and CO2 transfers across the alveolar-capillary membrane

A

When an endurance athletes exercises, nearly 25 times this quantity of O2 and CO2 transfers across the alveolar-capillary membrane

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12
Q

The ventilatory system is subdivided into what two parts

A

Conducting zone

Transitional and respiratory zones

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13
Q

What is the conducting zone

A

trachea, primary bronchioles, bronchus, bronchi and terminal bronchioles

do not contain alveoli;

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14
Q

What is conducting zone termed

A

anatomic dead space (i.e. air that fills the airway structure but does not participate in gas exchange)

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15
Q

What is the respiratory zone?

A

respiratory bronchioles, alveolar ducts and alveolar sacs

Site of gas exchange

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16
Q

Respiratory zone occupies about ? L and constitutes the largest portion of the lung volume

A

Occupies about 2.5 – 3.0 L and constitutes the largest portion of the lung volume

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17
Q

What is the Relationship between airway generation and total cross-sectional area of the various lung segments?

A

Airway cross-sectional area increases (and velocity slows) as air moves through the conducting zone to the terminal bronchioles.
At this stage, diffusion provides the primary means for gas movement and distribution

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18
Q

What is the equation for flicks law of diffusion?

A

Rate of diffusion = tissue surface area x concentration difference / thickness of membrane

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19
Q

Gas diffuses through a sheet of tissue at a rate that is?

A

D ∝ ∆P x A x S/d x √MW

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20
Q

What is ∆P

A

∆P = partial pressure difference

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21
Q

What is A

A

A = cross-sectional area

The greater the cross-sectional area of the diffusion pathway, the greater the total number of molecules that can diffuse.

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22
Q

What is S

A

S = solubility of the gas

The greater the solubility, the greater the # of molecules available to diffuse for any give partial pressure difference

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23
Q

What is d

A

d = distance

The greater the distance the molecules diffuse, the longer it will take the molecules to diffuse the entire distance.

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24
Q

What is √MW

A

√MW = square root of the molecular weight

The greater the molecular weight, the slower the molecule will diffuse across the membrane (i.e. bigger molecules have a slower velocity of kinetic movement)

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25
Q

What are the muscles of inspiration and what do they do

A

Scalenes and sternocleidomastoid: Pull rib cage up

External intercostals: pull rib cage out

Diaphragm moved toward the abdominal cavity

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26
Q

What are the muscles of expiration

A

Internal intercostals: pull rib cage down

Abdominals pull diaphragm up

Passive at rest

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27
Q

What is TV

A

Tidal volume = volume inspired or expired per breath

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28
Q

What is the average TV in men and women

A

Men=600 ml

Women=500 ml

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29
Q

What is IRV

A

Inspiration reserve volume = maximum inspiration at end of tidal inspiration

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30
Q

What is ERV

A

Expiration reserve volume= maximum expiration at the end of tidal expiration

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31
Q

What is TLC

A

Total lung capacity = Volume in lungs after maximum inspiration

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32
Q

What is the average TLC for men and women

A 
Men= 6000 ml
Women = 4200 ml
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33
Q

What is RLV

A

Residual lung volume = volume in lungs after maximum expiration

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34
Q

What is FVC

A

Forced Vital capacity = maximum volume expired after maximum inspiration

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35
Q

What is IC

A

Inspiratory capacity = maximum volume inspired following tidal expiration

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36
Q

What is the average IC for men and women

A 
Men = 3600
Women = 2400
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37
Q

What is FRC

A

Functional residual capacity = volume in lungs after tidal expiration

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38
Q

What is the average FRC in men and women

A 
Men = 2400
Women = 1800
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39
Q

During exercise what happens to EELV, IC, IRV and Te

A

EELV decreases
IC increases
IRV decreases
Te decreases

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40
Q

What is FEV1

A

Forced expiratory volume in one second (FEV1)

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41
Q

What does FEV1 –to-Forced vital capacity (FVC) ratio (FEV1/FVC) indicate

A

pulmonary airflow capacity

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42
Q

It reflects ____________ power and overall resistance to air movement in the lungs

A

It reflects pulmonary expiratory power and overall resistance to air movement in the lungs

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43
Q

Healthy individuals normally expel about ?% of the vital capacity in 1 second (i.e. FEV1/FVC ratio > ?%)

A

Healthy individuals normally expel about 85% of the vital capacity in 1 second (i.e. FEV1/FVC ratio > 85%)

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44
Q

Obstructive lung disease (e.g. COPD) reduced FEV1/FVC ratio; often values less than ?

A

Obstructive lung disease (e.g. COPD)

Reduced FEV1/FVC ratio; often values less than 70%

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45
Q

in COP is there

more or less elastic recoil pressure

more or less expiratory low

A

LESS

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46
Q

what is the equation for minute ventilation (VE)

A

Minute ventilation = breathing rate (Vf) x tidal volume (Vt)

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47
Q

What are TPYICAL VE values at rest

A

VE = 12 (vf) x 0.5 (Vt) L= 6 L/min (typical value at rest)

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48
Q

During exercise what happens to Vf

A

Vf increases to 35 – 45 breaths/min (some elite endurance athletes breathe as rapidly as 60-70 breaths/min)

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49
Q

During exercise what happens to Vt

A

Vt of 2.0 L and higher occur during exercise

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50
Q

What happens to VE during exercise

A

VE may increase 100 L or more (about 17-20 x resting value)

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51
Q

VT for trained and untrained individuals rarely exceed ?% of VC.

A

60% of VC

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52
Q

What is Anatomical dead space

A

A portion of the air in each breath does not enter the alveoli and participate in the gaseous exchange with the blood

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53
Q

Anatomical dead space ranges between what in healthy individuals

A

Ranges between 150 – 200 mL in healthy individuals

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54
Q

Does the composition of dead space air remain identical to ambient air

A

yes

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55
Q

What is alveolar ventilation

A

the portion of inspired air reaching the alveoli and participating in gas exchange

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56
Q

What is the equation for dead space minute ventilation

A

Dead space minute ventilation = Dead space(ml) x Vf (ml/min)

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57
Q

What is the equation for VA

A

VA= VE (ml/min) – dead space minute ventilation (ml/min)

VA= (Vt*Vf )-(Dead space(ml) x Vf (ml/min))

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58
Q

What has a greater impact on VA

-Vf (shallow breathing) or Vt (deep breathing)

A

Vt

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59
Q

During exercise, VT encroaches on ?

A

During exercise, VT encroaches on IRV

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60
Q

Deeper breathing = alveolar ventilation increases from ?% of the total VE at rest to more than ?% of the exercise VE

A

Deeper breathing = alveolar ventilation increases from 70% of the total VE at rest to more than 85% of the exercise VE

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61
Q

With more intense exercise, the increase in VT plateaus approximately ?% of the VC; VE increases further through nonconscious increase in ?

A

With more intense exercise, the increase in VT plateaus approximately 60% of the VC; VE increases further through nonconscious increase in VF

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62
Q

What does hyperventilation refer to

A

Refers to an increase in VE that exceeds the O2 requirements and CO2 elimination needs of metabolism

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63
Q

hyperventilation lowers normal alveolar ? and causes excess ? to leave the body.

A

normal alveolar CO2 and causes excess CO2 to leave the body.

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64
Q

Does hyperventilation increase or decrease PH

A

Increases = respiratory alkalosis

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65
Q

What are some symptoms of hyperventilation

A

lightheadedness; prolonged hyperventilation leads to unconsciousness from excessive CO2 unloading

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66
Q

What is partial pressure

A

The molecules of each specific gas in a mixture of gases exerts their own partial pressure

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67
Q

What is The mixture’s total pressure

A

the sum of the partial pressures of the individual gases in the mixture

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68
Q

What is Daltons Law

A

Partial pressure = percentage concentration of specific gas x total pressure of gas mixture

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69
Q

What is the total pressure of ambient air

A

760 mmHg

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70
Q

What is the percentage of O2, CO2, and N in ambient air

A 
O2 = 20.93
CO2 = 0.03
N = 79.04
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71
Q

What happens to the air what is passes down the respiratory tract

A

Air completely saturates with water vapor when it enters the nasal cavities and mouth and passes down the respiratory tract.

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72
Q

What is the pressure of water molecules in humidified air

A

47 mmHG

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73
Q

What is the PO2 in ambient air and tracheal air

A 
Ambient = 159
Tracheal = 149
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74
Q

What are the partial pressures of O@, CO2, and N in alveolar air

A
  1. 5% O2–> 14.5% x (760 – 47 mmHg) = 103 mmHg
  2. 5% CO2 –> 5.5% x (760 – 47 mmHg) = 39 mmHg

80% N2 –> 80% x (760 – 47 mmHg) = 571 mmHg

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75
Q

There alveolar partial pressures measure molecules against what side of the alveolar-capillary membrane

A

These values represent average pressures exerted by oxygen and carbon dioxide molecules against the alveolar side of the alveolar-capillary membrane

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76
Q

Do these values remain physiologically constant

A

They DO NOT remain physiological constant; rather they vary slightly with ventilatory cycle and adequacy of ventilation (i.e. V/Q ratio)

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77
Q

What explains why the partial pressure of alveolar gases remains relatively stable

A

a large volume of air remains in the lungs after each normal exhalation (FRC)

serves as a damper, so each incoming breath exerts only a small effect on alveolar air composition

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78
Q

Two factors that govern the rate of gas diffusion into a fluid?

A
  1. The pressure differential between the gas above the fluid and the gas dissolved in the fluid
  2. The solubility of the gas in fluid
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79
Q

Pressure differential

Molecules move from an area of ___ pressure to an area of ____ pressure.

A

Molecules move from an area of high pressure to an area of low pressure.

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80
Q

In humans what creates the driving force for gas diffusion across the pulmonary membrane

A

The pressure difference between alveolar and pulmonary blood gases

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81
Q

How is gas solubility expressed

A

Gas solubility is expressed as mL of gas per 100 ml (dL) of fluid

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82
Q

What is the solubility coefficient for CO2, O2 and N

A

CO2: dissolves most readily Solubility coefficient of 57.03 mL per dL of fluid

O2: Solubility coefficient of 2.26 mL per dL of fluid (relatively insoluble)

Nitrogen: The least soluble; solubility coefficient 1.30 mL per dL of fluid

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83
Q

What is the equation to calculate the amount of gas dissolved in a fluid

A

solubility coefficient x (gas partial pressure / total barometric pressure)

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84
Q

How does the exchange of gases between the lungs and blood and gas movement at the tissue level progresses

A

passively by diffusion, depending on their pressure gradients

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85
Q

What is the PO2 and CO2 in the pulmonary artery and in the alveoli

A

From pulmonary artery:
PO2 = 40 mmHg;
PCO2 = 46 mmHg

In alveoli:
PO2 = 100 mmHg;
PCO2 = 40 mmHg

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86
Q

Alveolar gas-blood gas equilibrium takes place in about ? seconds, or within one-third of _________ time through the lungs

A

Alveolar gas-blood gas equilibrium takes place in about 0.25 seconds, or within one-third of the blood’s transit (0.75 sec) time through the lungs

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87
Q

With increasing exercise: pulmonary capillaries inc or dec the blood volume within them by about ? times the resting value

maintain relatively fast or slow pulmonary blood flow velocity during physical activity

A

pulmonary capillaries increase the blood volume within them (distension) by about three times the resting value

maintain relatively slow pulmonary blood flow velocity during physical activity

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88
Q

Does partial pressure in the lungs vary

A

very little

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89
Q

At rest, PO2 in the fluid immediately outside the muscle cell averages _____mmHg and intracellular PCO2 averages ____ mmHg

A

At rest, PO2 in the fluid immediately outside the muscle cell averages 40 mmHg and intracellular PCO2 averages 46 mmHg

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90
Q

Blood carries oxygen in what 2 ways

A
  1. In physical solution dissolved in the fluid portion of the blood
  2. In loose combination with hemoglobin, the iron protein molecule within the red blood cell
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91
Q

In physical solution:
At an alveolar PO2 of 100 mmHg, only about ____ mL of gaseous oxygen dissolves in each dL of blood (this is due to oxygen’s relative insolubility in water); this equals ____mL of O2/ L of blood

A

In physical solution:
At an alveolar PO2 of 100 mmHg, only about 0.3 mL of gaseous oxygen dissolves in each dL of blood (this is due to oxygen’s relative insolubility in water); this equals 3mL of O2/ L of blood

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92
Q

The blood volume of a 70-kg person = 5L; thus 5 x 3 = 15 mL of O2 dissolves in the fluid portion of the blood.. Would sustain life for about ____ sec

A

The blood volume of a 70-kg person = 5L; thus 5 x 3 = 15 mL of O2 dissolves in the fluid portion of the blood.. Would sustain life for about 4 sec

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93
Q

What does the oxygen content in physical solution establish and determine?

A

Establishes the PO2 of the plasma and tissue fluids

Determines oxygen loading of hemoglobin in the lungs and subsequent release in the tissues

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94
Q

Hemoglobin is carried within the ______ trillion red blood cells of humans

This concentration carried _____ times more oxygen than normally dissolved in plasma

A

Hemoglobin is carried within the 25 trillion red blood cells of humans

This concentration carried 65-70 times more oxygen than normally dissolved in plasma

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95
Q

280 million hemoglobin molecules “capture” and transport about _____ mL of O2 in each liter of blood

A

280 million hemoglobin molecules “capture” and transport about 197 mL of O2 in each liter of blood

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96
Q

What is the reversible hemoglobin reaction

A

Hb4 + 4 O2 ↔︎ Hb4O8

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97
Q

What dictates the oxygenation of hemoglobin to oxyhemoglobin

A

the partial pressure of oxygen dissolved in physical solution

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98
Q

In men, each dL of blood contains about ____ g of hemoglobin (higher due to stimulating effects on red blood cell production of the testosterone)

In women, each dL of blood contains about _____ g of hemoglobin: this gender difference partly explains the lower aerobic capacity of women vs. men

A

In men, each dL of blood contains about 15 g of hemoglobin (higher due to stimulating effects on red blood cell production of the testosterone)

In women, each dL of blood contains about 14 g of hemoglobin: this gender difference partly explains the lower aerobic capacity of women vs. men

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99
Q

What is the blood’s oxygen carrying capacity

A

Blood’s oxygen carrying capacity = hemoglobin x oxygen capacity of hemoglobin

= 15 g/dl of blood x 1.34 mL/g
= 20 mL/ dl of blood
= 20 mL of O2 per L of blood

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100
Q

What does 100% O2 saturation indicate (in the lungs)

A

100% saturation indicates that oxygen combined with hemoglobin = the oxygen-carrying capacity of hemoglobin (20 mL per dl of blood

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101
Q

What is the equation for % saturation

A

%saturation = (O2 combined with hemoglobin/O2 capacity of hemoglobin) x100

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102
Q

Below what pressure of O2 does the binned O2 decline (in the lungs)

A

60 mmHg (90% saturated wit oxygen) below this pressure, the quantity of oxygen combined with hemoglobin declines more rapidly

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103
Q

In healthy individuals who breath ambient air at sea level, each dL of blood leaving the lungs carries approximately ___mL of oxygen – _____ mL bound to hemoglobin and _____ mL dissolved in plasma.

A

In healthy individuals who breath ambient air at sea level, each dL of blood leaving the lungs carries approximately 20mL of oxygen – 19.7 mL bound to hemoglobin and 0.3 mL dissolved in plasma.

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104
Q

At the tissue-capillary PO2 at rest of 40 mmHg, hemoglobin holds about 70% of its original oxygen. Thus, when blood leaves the tissues are returns to the heart, it carries about _____ mL of oxygen in each dL of blood, giving up ____ mL of oxygen to the tissues.

A

At the tissue-capillary PO2 at rest of 40 mmHg, hemoglobin holds about 70% of its original oxygen. Thus, when blood leaves the tissues are returns to the heart, it carries about 15 mL of oxygen in each dL of blood, giving up 5 mL of oxygen to the tissues.

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105
Q

What does The arterio-mixed-venous oxygen difference describe

A

The arterio-mixed-venous oxygen difference (a-vO2 difference) describes the difference between the oxygen content of arterial blood and mixed-venous blood

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106
Q

What is the a-vO2 difference at rest

A

The a-vO2 difference at rest normally averages 4 to 5 mL of oxygen per dl of blood (20 – 15 = 5)

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107
Q

What does The large quantity of oxygen still attached to the hemoglobin provide

A

provides a reserve so cells can immediately obtain oxygen should metabolic demand suddenly increase.

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108
Q

What happens to the a-vO2 difference during intense exercise

A

During intense exercise when extracellular PO2 decreases to nearly 15 mmHg, only about 5mL of oxygen remains bound to hemoglobin (a-vO2 difference increases to 15 mL per 100 ml of blood)

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109
Q

What is the Bohr effect

A

Any increase in plasma acidity and temperature causes the dissociation curve to shift downward and to the right

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110
Q

What does the Bohr effect indicate

A

that H+ and carbon dioxide alter hemoglobin’s molecular structure to decrease its oxygen-binding affinity

reduces effectiveness of hemoglobin to hold oxygen (i.e. increases O2 unloading).. Especially in PO2 20-50 mmHg

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111
Q

What are the 3 factors during intense exercise causing the Bohr Effect

A

(1) metabolic heat, (2) carbon dioxide and (3) acidity from blood lactate accumulation

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112
Q

What compound do RBCs produce during glycolysis

A

Red blood cells produce the compound 2,3-diphosphoglycerate (2,3-DPG) during glycolysis

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113
Q

what does it do

A

2,3-DPG binds loosely with subunits of the hemoglobin molecule, reducing its affinity for oxygen  causes greater oxygen release to the tissues for a given PO2

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114
Q

during strenuous exercise what does it aid in

A

During strenuous exercise, 2,3-DPG aids in oxygen transfer to the muscles

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115
Q

What is myoglobin

A

Myoglobin is an iron-containing protein in skeletal and cardiac muscle fiber. It provides intramuscular oxygen storage

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116
Q

What is the difference btwn hemoglobin and myoglobin

A

Myoglobin resembles hemoglobin because it also combines reversibly with oxygen but each molecule contains one iron atom while hemoglobin contains four.

Myoglobin adds additional oxygen to the muscle in the following chemical reaction:
Mb + O2 –> MbO2

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117
Q

What shape is the myoglobin cure

A

rectangular hyperbola

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118
Q

When does the quantity of O2 release from MbO2

A

when tissue PO2 declines below 5 mmHg

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119
Q

What is the equation for PACO2

A

PACO2 = VCO2 x (Pb –47) / VA

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120
Q

What is the equation for PAO2

A

PAO2=PiO2 - PaCO2/(VCO2/VO2)

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121
Q

What is Pb

A

Pb = barometric pressure (760 mmHg)

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122
Q

What is PiO2

A

PiO2 = inspired PO2 (20% x (760-47 mmHg)

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123
Q

What 2 factors control ventilation

A
  1. Neural

2. Humoral

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124
Q

What are the humoral factors

A
  1. Plasma PO2 and peripheral chemoreceptors

2. Plasma PCO2 and H+ concentration

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125
Q

What 2 factor regulate ventilation during exercise

A
  1. Chemical control

2. Nonchemical control

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126
Q

Inspiratory and expiratory neurons are located within the medial portion of the ?

A

Medulla

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127
Q

Where are the neurons that leads to inspiration located

A

Dorsal respiratory group (DRG)

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128
Q

Is The nervous signal that is transmitted to the inspiratory muscles instantaneous bust of AP?

A

No, it increases steadily in a ramp manner for about 2 sec, it then ceases abruptly for approximately the next 3 sec this turns off the excitation of the diaphragm and allows recoil of the lungs and chest wall to cause expiration.

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129
Q

Where are Most of the neurons in the DRG are located

A

nucleus tractus solitaris (NTS)

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130
Q

the nucleus tractus solitaris (NTS)

Receives feedback signals from?

A

peripheral chemoreceptors,

baroreceptors

receptors in the lungs (via vagal nerve afferents)

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131
Q

At rest what exerts the greatest control of pulmonary ventilation

A

The chemical state of the blood

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132
Q

Chemoreceptors detect?

A

Chemoreceptors detect changes in the O2 in the blood, and to a lesser extent CO2 and H+

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133
Q

Where are peripheral chemoreceptors located

A

located in the: carotid bodies and aortic bodies

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134
Q

Where are the carotid bodies located and what nerve is used to relay info

A

Located at the bifurcation of the common carotid arteries monitor blood before it enters brain

Relay information via glossopharyngeal nerve to the DRG

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135
Q

Where are the Aortic bodies located and what nerves relays info

A

Aortic bodies
Located along the arch of the aorta
Relay information via the vagus nerve to the DRG

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136
Q

When O2 concentration in the arterial blood falls below normal, the chemoreceptors become strongly stimulated (especially sensitive in the range of ______ mmHg of arterial PO2)

A

When O2 concentration in the arterial blood falls below normal, the chemoreceptors become strongly stimulated (especially sensitive in the range of 60 – 30 mmHg of arterial PO2)

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137
Q

Does CO2 and H have an effect on peripheral chemoreceptors?

A

CO2 and H+ more powerful in central chemoreceptors

However, stimulation of peripheral chemoreceptors by CO2 and H+ occurs 5x faster than central chemoreceptors

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138
Q

What rest what provides the most important respiratory stimulus

A

At rest arterial PCO2 in plasma

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139
Q

Does CO2 have a direct or indirect effect on central chemoreceptors

A

CO2 has an indirect effect on central chemoreceptors:
It reacts with water of the tissues to form H2CO3 which dissociates into H+ and HCO3

The H+ then have a potent direct stimulatory effect on respiration.

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140
Q

Is the BBB permeable to H ions

A

No

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141
Q

Why are PO2 values in carotid body and aortic body = arterial PO2

A

** extreme blood flow at the carotid and aortic bodies.

Virtually no O2 extracted from blood

Therefore, PO2 values in these regions = arterial PO2

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142
Q

Where does the stiumuls to breathe come from in breath holding

A

The stimulus to breathe comes from increases arterial PCO2 and H+

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143
Q

What happens when u hyperventilate before breath holding

A

alveolar air composition becomes more like ambient air

You have less CO2 in lungs, so it takes longer for it to accumulate

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144
Q

What is metabolic acidosis

A

Lactic acid is formed in the metabolism of muscle glycogen and blood glucose.

During heavy exercise, pyruvate production exceeds the rate of pyruvate utilization by the mitochondria

pyruvate accumulates in the muscle and arterial blood

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145
Q

What is buffering

A

The body will regulate pH by using various chemical and physiological BUFFERS

Buffering: reactions that minimize H+ concentrations (accepting H+ when [H+] is elevated and releasing H+ when [H+] is low)

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146
Q

What is an example of a chemical buffer

A

Bicarbonate buffer: carbonic acid (weak acid) and sodium bicarbonate (salt)

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147
Q

What happens in the muscle blood to the lungs

A

Lactic acid –> Lactate + H+ –> NaHCO3 (sodium bicarbonate) ↔︎ Sodium lactate + H2CO3 ↔︎ H2O + CO2

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148
Q

What represents 70% of bloods buffering capacity

A

Bicarbonate buffer

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149
Q

What is the general equation for the bicarbonate buffer

A

co2+h2o h2co3 hco3 +h

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150
Q

What are physiological buffers

what 2 systems provide the second line of defence

A

the pulmonary and renal systems present the second line of defence .
Their buffering function occurs only when a change in pH has already occurred

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151
Q

What is the ventilatory buffer

A

when H+ in extracellular fluid and plasma increases
respiratory center stimulated to increase alveolar ventilation

decrease in alveolar PCO2 and causes carbon dioxide to be “blown off” from the blood

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152
Q

What is the renal buffer

A

Excretion of H+ by the kidneys, although relatively slow, provides an important longer-term defense that maintains the body’s buffer reserve

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153
Q

At what exercise intensity does the HLA production exceed buffers ability to decrease H

A

greater than or equal to 50-70%

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154
Q

True or False

Pulmonary ventilation during light and moderate exercise closely couples with metabolism proportional to oxygen consumption and CO2 production

Alveolar (arterial) PCO2 generally averages 40 mmHg

A

TRUE lol

ie minute ventilation does not change much during mod exercise

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155
Q

During strenuous exercise what causes the additional ventilatory stimulous

A

large anaerobic component (lactate accumulation), increase CO2 and H+ provides additional ventilatory stimulus

The resulting hyperventilation reduces alveolar and arterial PCO2

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156
Q

Describe ventilation in steady rate exercise

A

VE increases linearly with O2 consumption and CO2 production (averaging between 20-25 L of air for each L of O2 consumed)

VE increases mainly through an increase in Vt;

at higher exercise intensities Vf takes on a more important role

VE achieved during this stage is sufficient to maintain alveolar PO2 and PCO2 near resting levels

Transit time for blood remains long enough for complete equilibration of lung-blood gases
Ventilatory equivalent (VE/VO2)
Healthy adults VE/VO2 = 25 (25  L of air per L of O2 consumed) during submaximal exercise up to 55% of VO2 max)
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157
Q

What happens to VE during intense sub maximal exercise

A

VE moves sharply upward and increases disproportionately in relation to VO2.

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158
Q

What is ventilatory threshold

A

The point at which VE increases disproportionately with VO2

marked increase in VE/VO2 ratio

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159
Q

What stimulates ventilation that increases VE/VO2 in intense exercise

A

The excess CO2 released from buffering reaction

160
Q

Conceptually, what does the LT represent

A

the lactate threshold (LT) represents an exercise level (power output, VO2, or energy expenditure) where tissue hypoxia triggers an imbalance between lactate formation and its clearance, with a resulting increase in blood lactate concentration

161
Q

What are the 3 different indicators or LT

A
  1. Fixed blood lactate concentration
  2. Ventilatory threshold
  3. Blood lactate-exercise VO2 response
162
Q

What is the immediate response of the respiratory system at high altitudes

A
  • Hyperventilation

- Body becomes more alkaline due to reductions of co2

163
Q

What is the longer terms effect of the respiratory system at high altitues

A
  • Hyperventilation

- Excretion of base HCO3 via the kidney leading to a reduction in alkaline reserve and restoring normal PH

164
Q

What is the equation for velocity of blood flow

A

Velocity of blood flow (v) = Blood flow (F)/Vascular cross-sectional area

v in aorta>arteries»>capillaries

165
Q

Describes the valves in the veins

A
  • Prevent back flow of blood
  • Don’t hinder the normal one-way flow of blood
  • Blood moves through the veins by action of near by active muscles and contraction of smooth muscle bands within the veins
166
Q

What is MAP

A

average pressure in your system; it’s the driving pressure that is driving the blood to the tissue

MAP = CO x TVR
MAP = SV x HR x TVR
MAP = [1/3 (Systolic-Diastolic pressure) ]+ Diastolic blood pressure
167
Q

What happens to ur arteries during resistance exercise

A

Arterial vascular compression: increases total peripheral resistances and reduces muscle perfusion

168
Q

What happens In an attempt to restore muscle blood flow

A

Muscle blood flow decreases proportionally to the % of maximum force capacity exerted

increase in sympathetic nervous system to increase Q and MAP

169
Q

During stead rate exercise there is rhythmic muscular contraction and vasodilation occurs; what effect does this have on TVR

A

vasodilation in the active muscle –> reduces TVR –> blood flow enhanced

170
Q

As exercise continues does SBP change?

A

systolic pressure declines (diastolic blood pressure remains unchanged)

because the arterioles in the active muscle continue to dilate –> reducing TVR

171
Q

What happens to systolic BP during graded exercise?

A

Initial rapid rise from resting levels in systolic blood pressure

the systolic blood pressure increases linearly with exercise intensity (this occurs despite a decrease in TVR)

reflects the hearts large cardiac output during maximal exercise

172
Q

What elevated BP more: exercising the LB or UP

A

Exercise with arms!
higher systolic and diastolic blood pressures than leg exercise performed at a give percentage of VO2 max

Smaller arm muscle mass greater resistance blood flow than the larger leg mass and blood supply

173
Q

Summarize the AP in SA node

A

?

174
Q

What are the 5 steps of the excitatory and conductive system of the heart

A
  1. An action potential is initiated in theSA nodeand travels by way of conduction fibers to theAV node. Action potential spreads throughout the cells of the atria.
  2. Impulse arrives at theAV nodewhere there is amomentary delaybecause action potentials are transmitted more slowly in these cells than in other cells of the conduction system.
  3. Impulse leaves the AV node and travels through theatrioventricular bundle(bundle of His) in theinterventricular septum.
  4. Atrioventricular bundles only travels a short distance before splitting intorightandleft bundle branches.
  5. Impulse travels to the myocardial cells of the ventricle by means of an extensive network of conduction fibers calledPurkinje fibers.
175
Q

What are the key words in order of the excitatory and conductive system (same as before but just describe in key words i.e. the ones bolded on her slide)

A

SA node - AV node - Delay - AV bundle of his - interventricular septum - right and left bundle branches - Purkinje fibers

176
Q

Where do sympathetic nerves that control the heart emerge from and what do they synapse with

A

emerge from the upper thoracic regions of the spinal cord and synapse with post ganglionic neurons in the sympathetic trunk

177
Q

What are the major hormones/NT that control the sympathetic activity of the heart and what are the receptors

A

Norepinephrine or epinephrine

ß1receptors

178
Q

In the SA nodes what happens when NE binds to ß1receptors

A

open funny channels and Ca2+ channels

179
Q

What happens when funny channels and Ca2+ channels open in the SA node

A

This will increase pacemaker potential –> shorter time to reach threshold potential

Accelerating self-excitation and increasing HR

180
Q

What happens in the AV node

A

the increased permeability to sodium and calcium makes it easier for the AP to excite succeeding portions of the fiber bundles = decreasing conduction time from atria to ventricles

181
Q

This increased HR is what type of effect

A

Chronotropic

182
Q

What is considered tachycardia

A

heart rate above 100 bpms

183
Q

During tachycardia what happens to the AP btwn the SA and AV node

A

Reduces time of AP propagation between SA and AV node = reduced time between atrial and ventricular contraction

184
Q

What is the ionotropic effect

A

Increases atrial and ventricular contraction (** increased Ca2+ permeability = stronger muscular contraction)

185
Q

What is the Starling effect

A
  1. As the length of the muscle fiber is increased the muscle fiber comes closer to itsoptimum lengthfor contraction.
  2. The stretching of the muscle fiber increases theaffinity of troponin for calciumwhich increases the crossbridge cycling.
186
Q

Can venous return affect the SV

A

Increased sympathetic activity to the venous system–>vasoconstriction –> increase venous pressure –> decrease the capacity of the venous system to hold blood

187
Q

How does sympathetic innervation also affects blood flow

A

Norepinephrine –> released by adrenergic fibers –>vasoconstrictor

188
Q

Adrenergic fibers contribute to the vasomotor tone, which is?

A

adrenergic constrictor nerves are active even while at rest

Sympathetic activity to veins –> venoconstriction –>increases venous return

189
Q

What does vasodilation do to adrenergic activity

A

It decreases it

190
Q

What nerve is associated with the parasympathetic control of the heart and where does it emerge from

A

Vagus nerve emerges from the medulla (pre and post ganglionic nerves)

191
Q

What are the receptors and what is the NT

A

Nicotinic receptors (pre-ganglionic) and muscarinic receptors (post ganglionic)

Ach

192
Q

What happen in the SA node when there is Ach

A

In the SA node, Ach binding to muscarinic receptors opens K+ channels –> hyperpolarization (-65 to -75 mv)

193
Q

What is there term when there is Reduced rate of rhythmicity in the SA node (decrease HR)

A

(bradycardia)

194
Q

If the vagal tone is strong enough what can happen to the SA node

A

it’s possible to completely stop the rhythmical self-excitation of this node

195
Q

When does central commend: feed-forward operate

A

Operates during the pre-exercise anticipatory period and during early stage of exercise

Neural input coordinates the rapid adjustment of heart and blood vessels to optimize tissue perfusion and maintain central blood pressure

196
Q

What type of afferents relay information from the muscle to the cardiorespiratory center

A

Type III and IV afferents relay information from the muscle to the cardiorespiratory center.

197
Q

What us a chemo receptor in the muscle

A

Chemoreceptors:
monitor the chemical state of the muscle

Metaboreflex: metabolite activation of type III and IV afferents

198
Q

What is a mechanoreceptor in the muscle

A

monitor the physical state of the muscle

Mechanoreflex: increase activation of mostly type II afferents in response to increase stimulation of mechanosensitive receptors

199
Q

What does the central command feedforward to the heart during exercise

A

The heart rapidly “turns on” during exercise by decreasing parasympathetic inhibitory input and increasing stimulating input from the brain’s central command.

200
Q

Is sympathetic contribution triggered by the central command?

A

Sympathetic contribution to the increase in HR is triggered by reflex activity and not central command

does not occur until achieving moderate exercise intensity

201
Q

What are the initial stimuli, physiological responses and results of the factors affecting stroke volume

A
  1. initial stimulus:

increase in sympathetic nerves to the heart

Decrease of parasympathetic nerves to the heart

  1. Physiological response:

Increase in stroke volume from sympathetic nerves

increase in HR from symp and dec in para sym

  1. Result:

inc in cardiac output

202
Q

What happens to blood flow at the onset of exercise in active muscles and non active muscles

A

Vascular component of active muscle increases by dilation of local arterioles

Nonactive tissue constrict (e.g. renal area

203
Q

What are the 2 factors that contribute to reduced blood flow to NON active tissues

A
  1. Increased sympathetic nervous outflow (vasoconstriction)

2. Local chemicals that directly stimulate vasoconstriction or enhance the effect of other vasoconstrictors

204
Q

Does Skeletal muscle blood flow closely couple to metabolic demand

A

yes

205
Q

At rest, only every ___-___ capillaries in the muscle tissue remains open

A

30-40

206
Q

What 3 factors occurs when dormant capillaries open =

A
  1. Increases total muscle blood flow
  2. Delivers a large blood volume with only a minimal increase in blood flow velocity
  3. Increases the effective surface area for gas exchange and nutrient exchange between the blood and muscle fibers
207
Q

Blood flow during exercise: Factors within active muscle:

Vasodilation occurs from _____ related to tissue ______

A

Vasodilation occurs from local factors related to tissue metabolism

208
Q

Decrease in tissue O2 leads to ?

A

potent local stimulus for vasodilation in skeletal and cardiac muscle

209
Q

CO2, H+, K+ and nitric oxide (NO) is released by _____ to contribute to vasodilation

A

by endothelial cells lining the blood vessels

210
Q

Local regulation–> strong control of blood flow to maintain __?

A

adequate regional blood

211
Q

What is the chain of reactions starting with an increase in tissue metabolism for factors within active muscles

A
  1. inc metabolism
  2. inc release of metabolic vasodilators to ECF
  3. arterioles dilate
  4. dec in resistance inc in blood flow
  5. O2 and nutrient supply to tissue increases as long as metabolism is increaed
212
Q

What happens to CO during light to mod aerobic ex at the start and steady state

A

Start:
increase: due to inc in SV and HR

Steady State:
Plateau: cardiorespiratory system is able to meet metabolic demand

213
Q

What happens to SV during light to mod aerobic ex at the start and steady state

A

Start:
Increase largely due to central command + sympathetic stimulation of the heart (contribution of muscle mechano- and metaboreflexes)

Increased sympathetic activity: increased calcium permeability at the SA node: ionotropic effects

Increase in venous return: stretches out the ventricle: increases force of ventricle (Frank-starling law)

Steady State:
Plateau: cardiorespiratory system is able to meet metabolic demand

214
Q

What happens to HR during light to mod aerobic ex at the start and steady state

A

Start:
Increase: largely due to central command + sympathetic stimulation of the heart (contribution of muscle mechano- and metaboreflexes)

Increase in sympathetic activity: NE increases rate of depolarization at the SA node: chronotropic effects

Decrease in parasympathetic activity (parasympathetic withdrawal)

Steady state:
Plateau: cardiorespiratory system is able to meet metabolic demand

215
Q

What happens to CO during MAXIMAL aerobic ex at the start and steady state

A

Start:
Increase: this is due to increase in SV and HR

High intensity:
Increases: SV will plateau, but HR will continue to increase

216
Q

What happens to SV during MAXIMAL aerobic ex at the start and steady state

A

Start:
Increase: largely due to central command + sympathetic stimulation of the heart (contribution of muscle mechano- and metaboreflexes)

Increased sympathetic activity: increased calcium permeability at the SA node: ionotropic effects

Increase in venous return: stretches out the ventricle: increases force of ventricle (Frank-starling law)

High intensity:
Plateau: Left ventricle cannot increase force-generating capacity any more

217
Q

What happens to HR during MAXIMAL aerobic ex at the start and steady state

A

Start:
Increase: largely due to central command + sympathetic stimulation of the heart (contribution of muscle mechano- and metaboreflexes)

Increase in sympathetic activity: NE increases rate of depolarization at the SA node: chronotropic effects

Decrease in parasympathetic activity (parasympathetic withdrawal)

High Intensity:
Increase in motor command + sympathetic activity and feedback from metabo- and mechanoreceptor activity

218
Q

What happens to SBP during MAXIMAL aerobic ex at the start and steady state

A

Start:
Increases: this is due to increase in CO

High Intensity:
Increase in CO that outweighs decrease in TVR, but near end-exercise it plateaus

219
Q

What happens to DBP during MAXIMAL aerobic ex at the start and steady state

A

Start:
No change: due to peripheral vasodilation (facilitates blood flow to the working muscle)

High intensity:
No change

220
Q

What happens to TVR/TPR during MAXIMAL aerobic ex at the start and steady state

A

Start:
Decreases: due to vasodilation in the active muscle

Vasodilation due to withdrawal of sympathetic tone (i.e. decrease in vasomotor tone) + increase in local chemical factors ( CO2 + H+ + NO ) –>all of which stimulate vasodilation

Importance of decrease in TVR: decrease in resistance at the level of the tissue –> increase blood flow

Second reason: MAP does not have to increase dramatically (MAP determined by Q and TVR)

High intensity:
same factors + plasma volume decreases: decrease in resistance

221
Q

What is the Fick method/equation for measuring CO

A

CO = {VO2 ml/min}/{avO2 diff ml/100ml blood}

X100

222
Q

What is the main difference in CO during exercise between untrained and trained

A

Because the maximal heart rates of all groups were similar, differences in cardiac output were almost entirely due to differences in maximal stroke volume.

Untrained CO = 20-22 L/min
max HR: 195 BPM
SV= 103-113 ml

Trained CO = 35-40 L/min
max HR: 195 BPM
SV=179-210 ml

223
Q

What are the 3 physiologic mechanisms that increase the hearts SV during exercise

A
  1. intrinsic to the myocardium, involves enhanced cardiac filling in diastole followed by a more forceful systolic contraction. (Enhanced diastolic filling)
  2. Neurohormonal influence involves normal ventricular filling with a subsequent forceful ejection and emptying during systole. (Greater systolic emptying)
  3. training adaptations that expand blood volume and reduce resistance to blood flow in peripheral tissues. (Cardiovascular drift)
224
Q

What contributes to the enhances diastolic filling

A

During exercise:

Venous return increases

End-diastolic volume increases (preload)

Stretches ventricles in diastole: produce a more forceful ejection stroke

225
Q

What contributes to greater systolic emptying

A

During exercise:

At rest 50-70 mL of total end-diastolic blood volume remains in the left ventricle following systole

During exercise, catecholamine release (sympathetic stimulation): enhance myocardial contractile force to augment stroke power and facilitate systolic emptying

Stretches ventricles in diastole: produce a more forceful ejection stroke

226
Q

During exercises what contributes to the Cardiovascular Drift?

A

Water loss through sweating: fluid shift from plasma to tissue

Fall in plasma volume: decreases central venous cardiac filling pressure (preoload) to reduce SV

Fall in SV: compensatory increase in HR to maintain a constant CO as exercise progresses

“Cardiovascular drift”: SV drift downward during prolonged stead-state exercise

227
Q

The cardiovascular shift occurs happens especially when?

A

especially during high ambient temperature

High body temperature: blood redistributed to skin: decrease in ventricular filling pressure and stroke volume

228
Q

Exercise oxygen consumption (a-v O2 diff) increases by what two mechanisms:

A
  1. Increased total quantity of blood pumped by the heart (i.e., increased cardiac output)
  2. Greater use of the already existing relatively large quantity of oxygen carried by the blood (i.e., expanded a-vO2 difference)

VO2 = CO x a-vO2

229
Q

What is the difference btwn the a-vO2 differ at rest and during exercise

A

At rest:
Arterial O2 content = 20 mL/dL
Venous O2 content = 15 mL/dL
a-vO2 difference = 5 mL/dL…. 75% of the blood’s original oxygen load still remains bound to hemoglobin

During exercise:
Arterial O2 content = 20 mL/dL
Venous O2 content = 2 – 5 ml/dL during maximal exercise!

a-vO2 difference = 15 mL/dL…. Most of the oxygen carried in arterial blood was extracted by the muscle

230
Q

What happens to the hematocrit when you exercise (sweat)

A

Hematocrit = the ratio of the volume of red blood cells to the total volume of blood.

Increase

When the fluid portion of the blood is reduced, the cellular and protein portions represent a larger fraction of the total blood volume; that is, they become more concentrated in the blood.

This hemoconcentration increases red blood cell concentration substantially—by up to 20% or 25%. Hematocrit can increase from 40% to 50%. However, the total number and volume of red blood cells do not change substantially.

231
Q

What happens to heart size with endurance training

A

Cardiac muscle mass and ventricular volume increase - cardiac hypertrophy (‘athlete’s heart’)

232
Q

What happens to SV with endurance training

A

Left ventricular chamber size increases : increase in SV at rest and during sub-maximal and maximal exercise

Training: increase in left ventricular volume (plasma volume expands with training) : increase in EDV - increase ventricular stretch - increase SV (increase in ejection fraction as ESV decreases)

233
Q

What happens to HR with endurane training

A

Max HR stays the same or decreases; resting and submaximal HR decreases

Mechanisms not understood, but training -increases parasympathetic tone and decreases sympathetic tone

234
Q

What happens to CO with endurance training

A

At rest and during submaximal exercise it does not change (because HR at rest and submaximal exercise decreases, but SV increases)

Max CO increases : due to increase in max SV

235
Q

What happens to BF with endurance training

A

Increased capillarization

Greater recruitment of existing capillaries

More effective blood flow redistribution

Increased total blood volume

236
Q

What happened to BP with endurance training

A

No significant change

237
Q

What happens to BV with endurance training

A

Increases due to an increase in plasma volume : protein synthesis is turned on (upregulated) by repeated exercise, and new proteins are formed

antidiuretic hormone and aldosterone, hormones that cause reabsorption of water and sodium in the kidneys

blood plasma inc. : increased fluid is kept in the vascular space by the oncotic pressure exerted by the proteins

Increase in RBC volume; but hematocrit (ratio of RBC:total blood volume, will decrease)

238
Q

What is the role role of Ca in the muscles fiber?

A

AP –> sarcoplasmic reticulum (SR) releases large quantities of stored calcium into the sarcoplasm

In resting state, tropomyosin molecules cover the myosin sites on the actin molecules, preventing the binding of the myosin heads

Once calcium ions are released from the SR –> bind to troponin on the actin molecules –> troponin moves the tropomyosin molecules off the myosin-binding sites on the actin molecules –> myosin heads can now attach to the binding sites on the actin molecules

239
Q

What are the 6 steps in a muscle contraction

  1. _____is released from the _____ of a MN and binds to receptors in the motor end plate. this elicits and potential that triggers an AP in the muscle cell
  2. AP propagates along the ______ and down the _____
  3. The AP triggers the release of ____ from the SR
  4. CA binds to _____ exposing myosin-binding sites
  5. _____ cycle begins
  6. Ca is actively transported back in lumen of SR following the AP
  7. ________ block myosin binding sites and the muscle relaxes
A
  1. ACh is released from the axon terminal of a MN and binds to receptors in the motor end plate. this elicits and potential that triggers an AP in the muscle cell
  2. AP propagates along the sarcolemma and down the T tubules
  3. The AP triggers the release of Ca from the SR
  4. CA binds to troponin exposing myosin-binding sites
  5. Cross bridge cycle begins
  6. Ca is actively transported back in lumen of SR following the AP
  7. Tropomyosin block myosin binding sites and the muscle relaxes
240
Q

What contains the binding site for the ATP molecule

A

The myosin head

241
Q

What enzyme is located on the myosin head

A

adenosine triphosphatase

242
Q

How long does muscle contraction last

A

continues as long as calcium is available in the sarcoplasm

243
Q

At the end of the contraction where is calcium pumped

A

calcium is pumped back into the SR, where it is stored until a new AP arrives at the muscle fiber membrane

244
Q

Is energy required for both the contraction and relaxation phase?

A

YES

Calcium returned to SR by active calcium-pumping system –> requires AP

Therefore, energy is required for both the contraction and relaxation phase

245
Q

Are type 1 fibers fast or slow twitch - how long does it take to reach peak tension

A

SLOW

100 ms

246
Q

Are type 2 fibers fast or slow twitch - how long does it take to reach peak tension

A

Fast

50ml

247
Q

What are the different types of type 2 fibers and which is most frequently recruited

A

Type II a = most frequently recruited

Type II x and Type II c

248
Q

Which fiber type is better for aerobic

A

Type 1

249
Q

Which fiber type is better for anaerobic

A

Type II

250
Q

How does type 1 and type 2 differ in ATP production

A

Type 1:
Very efficient at producing ATP from the oxidation of carbohydrate and fat

Type II:
In the absence of adequate oxygen, ATP is formed through anaerobic pathways, not oxidative pathways

251
Q

Which type is beneficial for high aerobic endurance

A

Type 1:

recruited most often during low-intensity endurance events (e.g. marathon) and during most activities for which muscle force requirements are low

Long distance running

252
Q

Which type is better suited for short high intensity sprints

A

Type IIa fibers used during shorter, higher-intensity endurance events, such as the mile run or the 400 m swim

Sprint – ATP from glycolysis (anaerobic)

253
Q

Generally, how is muscle fiber type determined

A

genetically determined, changing little from childhood to middle age

254
Q

After innervation is established, how do muscle fibers differentiate?

A

according to the type of alpha-motor neuron that stimulates them.

255
Q

What is fiber type shifting in COPD patients

A

COPD patients shift from type 1 to type 2

256
Q

What is the principle of orderly recruitment

A

As the intensity of an activity increases, the number of fibers recruited increases:
Type I - type II a - type IIx

257
Q

What mechanism explains the principle of orderly recruitment

A

size principle, which states that the order of recruitment of motor units is directly related to the size of their motor neuron.

smaller motor neurons will be recruited first (type 1)

258
Q

What are concentric contractions considered and what happens to the filaments

A

the thin filaments are pulled towards the center of the sarcomere

joint movement is produced

concentric contractions are considered dynamic contractions

259
Q

What kind of muscle contraction occurs when no joint movement is produced

A

Static or isometric muscle contraction

muscle generate force, but its length remains static (unchanged)

260
Q

What is an eccentric contraction

A

muscles can exert a force even when lengthening

joint movement occurs also a dynamic contraction

261
Q

What 4 facotrs influence force generation

A
  1. motor units and muscle size
  2. frequency of stimulation of the motor units: rate coding
  3. Motor units and muscle size (length)

Speed of contraction

262
Q

What is the effect of motor units and muscle size on force generation

A

Type II motor units generate more force than type I motor units because a type II motor unit contains more muscle fibers than type I motor units

263
Q

What is the effect of Frequency of stimulation of the motor units: rate coding on force generation

A

A single motor unit can exert varying levels of force depending on the frequency at which it is stimulated

264
Q

What is a twitch

A

smallest contractile response of a muscle fiber or a motor unit to a single electrical stimulus

265
Q

What is summation

A

series of stimuli in rapid sequence prior to complete relaxation elicit an even greater increase in force or tension

266
Q

What is tetanus

A

when Continues stimulation–> tetanus–> peak force or tension of the muscle fiber or motor unit

267
Q

Does sarcomere length affect muscle force

A

yes, there is an optimal length for each muscle relative to its ability to generate force –> optimal overlap between the thick and thin filaments (maximizing cross-bridge interaction)

268
Q

How does contraction speed affect force generation

A

during concentric contraction –> maximal force decreases as speed increased

269
Q

What is a nerve impulse

A

electrical signal arises when a stimulus is strong enough to change the normal electrical charge of the neuron

270
Q

What is the resting membrane potential

A

-70 mv

271
Q

is the cell membrane more permeable to K or NA

A

K

272
Q

What does the NA/K pump do

A

maintains the imbalance by actively transporting K+ in and Na+ out

more +ve charged ions outside the cell vs. inside

273
Q

What is an action potential

A

rapid and substantial depolarization of the neuron’s membrane

Usually lasts about 1 ms

RMP changes from -70 mv - +30 mv then rapidly returns to its resting value

274
Q

What is a threshold

A

the membrane voltage at which a graded potential becomes an AP

All-or-none principle

275
Q

What is an absolute refractory period

A

When Na+ channels are closed, and K+ are open, and repolarization is occurring another AP cannot be evoked even IF THE STIMULUS IS STRONG ENOUGH

from +30 to -70

276
Q

What is a relative refractory period

A

when a segment of the axon’s Na+ gates are open and its in the process of generating an AP, it can respond to another stimulus

277
Q

Is a myelinated axon fatty

A

yes

278
Q

myelin sheath is formed by specialized called called the ?

A

Schwann cells

279
Q

What is a node of ranvier

A

has gaps between the adjacent Schwann cells

leaving the axon uninsulated at these points

280
Q

What is saltatory conduction

A

AP jumps from one node to the next as it traverses a myelinated fiber

Velocity of myelinated fiber is much faster vs. non-myelinated fiber

281
Q

what is the relationship between nerve diameter and impulse speed

A

Neurons of larger diameter conduct nerve impulses faster than neurons of smaller diameter

large neurons present less resistance to local current flow

282
Q

What is a synapse and what are the 2 different types

A

the site of the AP transmission from the axon terminals of one neuron to the dendrites or soma of another

  1. Chemical synapse
  2. Electrical synapse
283
Q

what is the main NT for motor neurons and parasympathetic neurons

A

Ach

284
Q

What are adrenergic nerve and what are cholinergic nerve

A

Nerves that release norepinephrine: adrenergic nerves

Nerves that release Ach: cholinergic

Ach and NE can be either excitatory or inhibitory

285
Q

Where does summation of AP’s occur

A

at the axon hillock

286
Q

What is the difference btwn spatial and temporal summation

A

Spatial: simultaneous stimulation by several presynaptic neurons

Temporal: high frequency stimulation by one presynaptic neuron

287
Q

What are the right and left cerebral hemispheres connected by

A

corpus callosum

288
Q

The cerebral cortex consists of what portions of the brain

A

outer portion (grey) unmyelinnated

289
Q

the cerebral cortex is the site of mind and intellect, allows people to ?

A

Think, and be aware or sensory stimuli - conscious brain

290
Q

What are the 5 lobes of the cerebrum

A
  1. Frontal
  2. temporal
  3. Occipital
  4. Parietal
  5. Insular
291
Q

What is the frontal lobe responsible for

A

general intellect and motor control (primary motor cortex located here)

292
Q

What is the temporal lobe responsible for

A

auditory input and interpretation

293
Q

What is the parietal lobe responsible for

A

general sensory input and interpretation (primary sensory cortex located here)

294
Q

What is the occipital lobe responsible for

A

visual input and interpretation

295
Q

What is the insular lobe responsible for

A

diverse functions, usually linked to emotion and self-perception

296
Q

What is the primary motor cortex responsible for

A

the control of fine and discrete muscle movement

297
Q

What are the neurons known as in the PMC

A

pyramidal cells: conscious control of skeletal muscles

298
Q

Cell bodies in the primary motor cortex and their axons form the ?

A

extrapyramidal tracts

Provide the major voluntary control of skeletal muscle

299
Q

Where is the premotor cortex located and what is it responsible for

A

Anterior to the precentral gyrus in the frontal lobe

Learned motor skills of repetitious or patterned nature are stored here

300
Q

what part of the brain is considered the memory bank

A

Premotor cortex

301
Q

What is the diencephalon composed of

A

the thalamus and hypothalamus

302
Q

The thalamus is the integration center for what

A

sensory integration center: all sensory input (except smell) enters the thalamus and is relayed to the appropriate area of the cortex
v. important for motor control

303
Q

What is the hypothalamus responsible for

A

responsible for maintaining homeostasis by regulating all processes that affect the body’s internal environment

(bp, resp, temp, appetite)

304
Q

The cerebellum is important in ?

A

coordinating movement

305
Q

how does the cerebellum assist the PMC

A

smoothing out of the movement

Primary motor cortex –> decision to move –> cerebellum notes the desire action –> compares the intended movement with the actual movement based on sensory feedback from the muscles and joints

If action is different than planned, the cerebellum informs the higher centers of the discrepancy so corrective action can be initiated

306
Q

Where is the reticular formation located and what is it

A

Collection of neuron in the brainstem

307
Q

What is it responsible for

A

Integrates various incoming and outgoing signals

These signals originate from the stretching of sensors in joints and muscles, and other receptors

308
Q

The brain stem:

Coordinate ________ function

Maintain ______ tone

Control cardiovascular and ______ function

Determine state of _______ (arousal and sleep

A

Coordinate skeletal muscle function

Maintain muscle tone

Control cardiovascular and respiratory function

Determine state of consciousness (arousal and sleep

309
Q

What provides the major conduit for the two-way transmission of information from the skin, joints, and muscles to the brain.

A

the spinal cord

310
Q

What describes the limbs of this core

A

The ventral (anterior) and dorsal (posterior)

311
Q

the SC contains what 3 types of neurons

A 
motor neurons (ventral), 
Sensory neurons (dorsal),  interneurons.
312
Q

What are the 5 types of receptors that the sensory division receives info from

A
  1. mechanoreceptors
  2. thermoreceptors
  3. nociceptors
  4. photoreceptors
  5. chemoreceptors
313
Q

Mechanoreceptors respond to:

A

mechanical forces (pressure touch vibration or stretch)

314
Q

Thermoreceptors respond to:

A

changes in temperature

315
Q

Nociceptors respond to

A

painful stimuli

316
Q

Photo receptors respond to:

A

electromagnetic radiation (light) to allow vision

317
Q

Chemoreceptors respond to:

A

chemical stimuli, such as from foods, odors, or changes in blood or tissue concentrations of substances such as oxygen, carbon dioxide, glucose, and electrolytes

318
Q

For the body to respond to sensory stimuli, the sensory and motor divisions of the nervous system must function together in the following sequence of events: (5)

A
  1. A sensory stimulus is received by sensory receptors (e.g., pinprick).
  2. The sensory action potential is transmitted along sensory neurons to the CNS via the dorsal root
  3. The CNS interprets the incoming sensory information and determines which response is most appropriate, or reflexively initiates a motor response.
  4. The action potentials for the response are transmitted from the CNS along α-motor neurons.
  5. The motor action potential is transmitted to a muscle, and the response occurs.
319
Q

Where are sensory impulses integrated that terminate in the SC?

A

Sensory impulses that terminate in the spinal cord are integrated there

320
Q

Sensory signals that terminate in the lower brain stem and cerebellum result in ?

A

subconscious motor reactions of a higher and more complex nature than simple spinal cord reflexes

321
Q

Sensory signals that terminate at the thalamus begin to enter the level of?

A

consciousness, and the person begins to distinguish various sensations

322
Q

Only when sensory signals enter the ________ can one discretely localize the signal.

A

Only when sensory signals enter the cerebral cortex can one discretely localize the signal.

323
Q

Once the sensory impulse is received, it may evoke a motor response, regardless of the level at which the sensory impulse stops.

This response can originate from any of three levels:

A
  1. The spinal cord
  2. The lower regions of the brain
  3. The motor area of the cerebral cortex
324
Q

What is a muscle spindle

What does it consist of

A

Group of specialized muscle fibers found between regular skeletal muscle fibers referred to as extrafusal (outside the spindle) fibers.

A muscle spindle consists of 4 to 20 small, specialized intrafusal (inside the spindle) fibers and the nerve endings, sensory and motor, associated with these fibers.

A connective tissue sheath surrounds the muscle spindle and attaches to the endomysium of the extrafusal fibers.

325
Q

The intrafusal fibers are controlled by specialized motor neurons, referred to as ?

A

γ-motor neurons (or gamma motor neurons)

326
Q

Approximately _____ muscle fibers are usually connected with each Golgi tendon organ.

A

5 to 25

327
Q

Golgi tendon organs are sensitive to ____ in the muscle–tendon complex

A

tension

328
Q

These sensory receptors are _____ in nature, performing a protective function by reducing the potential for injury

A

These sensory receptors are inhibitory in nature, performing a protective function by reducing the potential for injury

329
Q

When golgi tendons are stimulated, these receptors inhibit the ____ muscles and excite the ______ muscles.

A

inhibit the contracting (agonist) muscles and excite the antagonist muscles.

330
Q

What 3 things does the endocrine system include

A
  1. Consists of a host organ,
  2. minute quantities of chemical messengers (hormones)
  3. target receptor (organ)
331
Q

What is the difference between and endocrine and an exocrine gland

A

Endocrine glands:
No ducts
Secrete substances directly into extracellular spaces around the gland

Exocrine glands
Contain secretory ducts that carry substances directly to a specific compartment or surface
Example: sweat glands

332
Q

Steroid-derived hormones

Soluble in blood plasma?

Receptor location?

Response to ___________ binding: activates genes for transcription and translation

E.g.: ?

A

Steroid-derived hormones

Not readily soluble in the blood plasma

Receptor location: cytoplasm or nucleus; some have membrane receptors

Response to receptor-ligand binding: activates genes for transcription and translation

E.g.: cortisol

333
Q

Amine and polypeptide hormones

Soluble in blood plasma?

Hard uptake at target sites?

Receptor location?

Response to ___________ binding: activation of second messenger system; may activate ____

E.g.: insulin, glucagon

A

Amine and polypeptide hormones

Soluble in blood plasma

NO! EASY uptake at target sites

Receptor location: on cell membrane

Response to receptor-ligand binding: activation of second messenger system; may activate genes

E.g.: insulin, glucagon

334
Q

What does cyclic AMP do?

A

Binding of a hormone with its specific receptor in the plasma membrane –> alters cell permeability to a particular target OR activates intracellular substances

335
Q

Epinephrine and glucagon (hormones) –> Act as ____ messenger to react with ______ cyclase in the plasma membrane

forms cyclic AMP (_____ messenger)–>activates protein _____ –> activates the target enzyme to alter cellular function

A

Epinephrine and glucagon (hormones) –> Act as first messenger to react with adenylate cyclase in the plasma membrane –>forms cyclic AMP (second messenger) –> activates protein kinase –> activates the target enzyme to alter cellular function

336
Q

What 3 factors affect the first steps in initiating hormone action

A
  1. Hormone concentration in the blood
  2. Number of target cell receptors for the hormone
  3. Sensitivity or strength of the union between the hormone and the receptor
337
Q

What is upregulation and down regulation

A

Upregulation: target cells form more receptors in response to increasing hormone levels (to increase the hormone’s effect)

Downregulation: loss of receptors to prevent target from overresponding to chronically high levels

338
Q

A hormone increases enzyme activity in what three ways

A
  1. Stimulate enzyme production.
  2. Combines with the enzyme to alter its shape and ability to act
  3. Activates inactive enzyme forms
339
Q

Give an example of stimulating enzyme production

A

steroid hormones –> direct gene activation –> protein synthesis (proteins for growth and repair, enzymes that have numerous effects on cellular processes

340
Q

What is it called when hormones combine with the enzyme to alter its shape and ability to act

A

allosteric modulation: increases or decreases the enzyme’s catalytic effectiveness.

341
Q

Four factors determine plasma concentration of a particular hormone

A
  1. Quantity synthesized in the host gland
  2. Rate of either catabolism or secretion into the blood
  3. Quantity of transport proteins present (for some hormones)
  4. Plasma volume changes
342
Q

How does Rate of either catabolism or secretion into the blood determine concentration of a hormone

A

As the hormone is metabolized, it becomes inactive: inactivation takes place at or near receptors or in the liver or kidneys

During exercise: blood flow to renal areas decreases: hormone inactivation rates decrease and plasma hormone concentrations rise

343
Q

How do Plasma volume changes During prolonged exercise affect hormone concentration

A

plasma volume decreases: increase in plasma hormone concentration, even without an absolute change in hormone amount.

344
Q

What 3 factors stimulate endocrine activity

A
  1. Hormone stimulation
  2. Humoral stimulation
  3. Neuron stimulation
345
Q

What is hormone stimulation

A

When hormones influence secretion of other hormones

346
Q

What is humoral stimulation

A

Changing levels of ions and nutrients in the blood, bile and other body fluids stimulate hormone release

ex: increase in blood sugar

347
Q

What is neural stimulation

A

Neural activity affects hormone release

Example: sympathetic neural activation of the adrenal medulla during stress releases epinephrine and norepinephrine

dec in insulin release to decrease the decline in blood sugar to ensure neural tissue has fuel

348
Q

The pituitary gland secrets 6 ?

A

specialized polypeptide hormones

each have their one hypothalamic releasing hormone (releasing factor)

  1. lactogen
  2. gonadotropic
  3. ACTH
  4. thyrotropin
  5. GH
  6. Endorphins
349
Q

What is Secrets proopimoleanocortin (POMC)

A

precursor molecule of other active molecules

ACTH, melanocortin peptides and beta-endorphins

350
Q

Growth hormone-releasing factor from the _____________ influences resting growth hormone (GH) secretion by directly stimulating the ____ pituitary gland

A

Growth hormone-releasing factor from the hypothalamus influences resting growth hormone (GH) secretion by directly stimulating the anterior pituitary gland

351
Q

What does GH promote

A

promotes cell division and cellular proliferation through the body

352
Q

GH facilitates protein synthesis in what three ways

A
  1. Increasing amino acid transport through the plasma membrane
  2. Stimulates RNA formation
  3. Activating cellular ribosomes that increase protein synthesis
353
Q

What happens to GH secretion during EX

A

MORE

354
Q

What is the effect of the extra GH

A

Decreasing tissue glucose uptake

Increasing free fatty acid mobilization

Enhancing liver gluconeogenesis

Net metabolic effect  increased exercise induced GH = preserved plasma glucose concentration for the CNS and muscle functions

355
Q

What are the peptide messengers produced in the liver as a result of increased GH

A

insulin-like growth factors IGF-1 and IGF-II

356
Q

what are IGFS

A

mediate many of GH’s effects.

In response to GH stimulation

binding proteins within muscle, nutritional status, and plasma insulin levels.

357
Q

What does thyrotropin (TSH) control

A

hormone secretion by the thyroid gland and maintains growth and development of the thyroid gland

358
Q

ACHT :

enhances _____ mobilization from the adipose tissue

increase ____genesis

stimulates _____ catabolism

A

ACHT:

enhances fatty acid mobilization from the adipose tissue

increase glycogenesis

stimulates protein catabolism

359
Q

PRL levels________ at high exercise intensities and return toward baseline within __ min during recovery

A

PRL levels increase at high exercise intensities and return toward baseline within 45 min during recovery

in females exercise induced PRL level can affect the menstrual cycle

360
Q

What are the 2 gonadotropic hormones that stimulate male and female sex organs to grow

A

FSH and LH

361
Q

what does FSH do

A

Initiates follicle growth in the ovaries = secretion of estrogen

362
Q

what does LH do

A

complements FSH action: causes estrogen secretion and rupture of the follicle = ovum pass through the fallopian tube for fertilization

363
Q

What do they do in males

A 
FSH = stimulates germinal epithelium growth in the testes and promotes sperm development. 
LH = stimulates the testes to secrete testosterone
364
Q

What 2 hormones are stored in the post pit

produced in hypothalamnus

A

ADH and oxytocin

365
Q

Under influence of TSH produced by the anterior pituitary gland

Release _______(calcium-regulating hormone)

Release \_\_\_\_\_\_ (T4) and \_\_\_\_\_\_\_\_\_ (T3)
T3 is the active form of thyroid hormone
A

Release calcitonin (calcium-regulating hormone)

Release thyroxine (T4) and triiodothyronine (T3)
T3 is the active form of thyroid hormone
366
Q

What does T4 stimulate

A

effect on enzyme activity = raises metabolism on all cells except in the brain, spleen, testes, uterus and thyroid gland itself

Abnormally high T4 = raises basal metabolic rate (BMR) up to fourfold!! person loses weight rapidly hell 2 the yeah

367
Q

Does exercise increase T4

A

yes by 35%

368
Q

What does T3 facilitatte

A

neural reflex activity

369
Q

What are the 4 effects of hyperthyroidism

A
  1. Increased oxygen consumption and metabolic heat production during rest (heat intolerance is a common complaint)
  2. Increased protein catabolism and subsequent muscle weakness and weight loss
  3. Heightened reflex activity and psychological disturbances that range from irritability and insomnia to psychosis
  4. Rapid heart rate (tachycardia)
370
Q

What are the 4 effects of hypothyroidism

A

1. Reduced metabolic rate and cold intolerance from reduced internal heat production

  1. Decreased protein synthesis produces brittle nails, thinning hair, and dry, thin skin
  2. Depressed reflex activity, slow speech and thought processes, and feeling of fatigue (in infancy causes cretinism, marked by decreased mental capacity)
  3. Slow heart rate (bradycardia)
371
Q

What does the adrenal medulla secrete

A

Prolongs sympathetic effects by secreting epinephrine and norepinephrine (collectively called catecholamines)

EPI = 80% of secretions

Stimulates glyogenolysis

372
Q

Norepinephrine increases markedly at intensities that exceed _____ VO2 max

Epinephrine levels remain unchanged until exercise intensity exceeds _____ level

all effects benefit the physical activity response.

A

Norepinephrine increases markedly at intensities that exceed 50% VO2 max

Epinephrine levels remain unchanged until exercise intensity exceeds 60% level

373
Q

The adrenal cortex is stimulated by what hormone from where

A

stimulated by corticotropin from anterior pituitary to release adrenocortical hormones

374
Q

What do mineralocoticoids regulate

A

minerals: salt sodium and K+ in the extracellular fluid

375
Q

What does aldosterone the mineraocoticoid do

A

Stimulates Na+ reabsorption along with fluid in the distal tubules of the kidneys by increasing synthesis of sodium transporter proteins

376
Q

Is the renin-angiotensin mechanism increased or decreased during sympathetic stimulation during exercise

A

increased

377
Q

Where is renin secreted from and where

A

prolonged exercise without adequate fluid replacement can lead to dehydration

Dehydration can cause a decrease in blood pressure which is sensed by kidneys

Renin is secreted by the kidneys

Renin converts the protein angiotensinogen released by the liver to angiotensin I

Angiotensin converting enzyme in the lungs converts angiotensin 1 to 2

Angiotensin 2 stimulates the adrenal cortex to release aldosterone and vasoconstricts blood vessels increasing BP

Aldosterone acts on the kidneys to increase Na resorption and excret postassium - the conservation of water leads to an increase in plasma volume and an increase in BP

378
Q

Glucocorticoids = corticotropin-releasing factor from the hypothalamus causes release of _____ from the anterior pituitary = promotes release of glucocorticoid by the adrenal _____

Cortisol = major glucocorticoid of the adrenal _____

A

Glucocorticoids = corticotropin-releasing factor from the hypothalamus causes release of ACTH from the anterior pituitary = promotes release of glucocorticoid by the adrenal cortex

379
Q

Cortisol = major ____ of the adrenal ____

A

Cortisol = major glucocorticoid of the adrenal cortex

380
Q

What happens to cortisol output with exercise intensity

A

cortisol output increases with exercise intensity; this heightened output accelerates lipolysis, ketogenesis, and proteolysis.

381
Q

Testosterone = most important __________ secreted by the ________ initiates sperm production and development of male secondary sex characteristics

A

Testosterone = most important androgen secreted by the testes initiates sperm production and development of male secondary sex characteristics

382
Q

Ovaries provide the primary source of?

A

estrogens, estradiol and progesterone

Regulates ovulation. menstruation and physiological adjustments during pregnancy

383
Q

Testosterone ad swimming

A

the swim testosterone and cortisol are lower and after the swim both testosterone and cortisol is higher and during recovery those remain elevated.

As they train testosterone and cortisol before after and during recovery were lower

384
Q

What is type 1 diabetes

A

Type 1 Diabetes represents an autoimmune response, possibly from a single protein that renders the beta-cells incapable of producing insulin and often other pancreatic hormones.

385
Q

What 3 factors can produce high blood glucose in type 2 diabetes

A
  1. Inadequate insulin produced by the pancreas to control blood sugar (relative insulin deficiency)
  2. Decreased insulin effects on peripheral tissue (insulin resistance), particularly skeletal muscle
  3. Combined effect of factors 1 and 2
386
Q

What is the relationship between insulin release and physical activity intensity

A

As intensity increases, there is a decreases in insulin secretion

387
Q

Prolonged physical activity derives progressively more energy from ___________ from the adipocytes from reduced insulin output and decreased carbohydrate reserves.

A

Prolonged physical activity derives progressively more energy from free fatty acids mobilized from the adipocytes from reduced insulin output and decreased carbohydrate reserves.

388
Q

What does glucagon stimulate

A

primarily stimulates both glycogenolysis (with adenylate cyclase) and gluconeogenesis(amino acid uptake) by the liver and increases lipid catabolism.

389
Q

What does GH stimulate and what happens in trained ppl

A

Growth hormone (GH) stimulates lipolysis and inhibits CHO breakdown

Trained individuals less rise in blood GH levels at any given physical activity intensity

390
Q

What does ACTH stimulate and what happens in trained individuals

A

stimulates adrenal cortex to increases free fatty acid mobilization for energy

Trained individuals Increases ACTH release during physical activity = more fat catabolism and spare glycogen (benefits prolonged high-intensity exercise)

391
Q

What happens to FSH, LH and Testosterone in trained individuals

A

Decrease in reproductive hormone responses in men and women.

Male endurance athletes decrease in testosterone levels, but LH and FSH remain stable

392
Q

What is the effect of ADH in trained individuals

A

no diff

393
Q

What happens to T4 in trained individuals

A

over production of T3 and T4 however, no evidence indicates a inordinately high BMR levels

394
Q

What happens to aldosterone in trained individuals

A

no change

395
Q

What happens to cortisol in trained individuals

A

cortisol levels increase less in trained vs. untrained individuals who perform the same absolute level of submaximal exercise

396
Q

What happens to NE and EP in trained individuals

A

sympsubmaximal workload remains lower in trained vs. untrained.
athoadrenal activity in response to absolute

397
Q

What happens in insulin and glucagon in trained individuals

A

trained state requires less insulin and glucagon at any stage from rest through light to moderately intense physical activity

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