Final Flashcards
(397 cards)
1
Q
Pulmonary ventilation
A
the process of moving and exchanging ambient air with the lungs.
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
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
4
Q
What does the pulmonary artery do
A
Pulmonary artery: carried deoxygenated blood from the heart to the lungs
5
Q
What does the pulmonary vein do
A
carried oxygenated blood from the lungs to the heart
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.
7
Q
The lungs contain more than ________ alveoli
A
The lungs contain more than 600 million alveoli
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
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
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
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
12
Q
The ventilatory system is subdivided into what two parts
A
Conducting zone
Transitional and respiratory zones
13
Q
What is the conducting zone
A
trachea, primary bronchioles, bronchus, bronchi and terminal bronchioles
do not contain alveoli;
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)
15
Q
What is the respiratory zone?
A
respiratory bronchioles, alveolar ducts and alveolar sacs
Site of gas exchange
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
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
18
Q
What is the equation for flicks law of diffusion?
A
Rate of diffusion = tissue surface area x concentration difference / thickness of membrane
19
Q
Gas diffuses through a sheet of tissue at a rate that is?
A
D ∝ ∆P x A x S/d x √MW
20
Q
What is ∆P
A
∆P = partial pressure difference
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.
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
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.
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)
25
What are the muscles of inspiration and what do they do
Scalenes and sternocleidomastoid: Pull rib cage up
External intercostals: pull rib cage out
Diaphragm moved toward the abdominal cavity
26
What are the muscles of expiration
Internal intercostals: pull rib cage down
Abdominals pull diaphragm up
Passive at rest
27
What is TV
Tidal volume = volume inspired or expired per breath
28
What is the average TV in men and women
Men=600 ml
| Women=500 ml
29
What is IRV
Inspiration reserve volume = maximum inspiration at end of tidal inspiration
30
What is ERV
Expiration reserve volume= maximum expiration at the end of tidal expiration
31
What is TLC
Total lung capacity = Volume in lungs after maximum inspiration
32
What is the average TLC for men and women
```
Men= 6000 ml
Women = 4200 ml
```
33
What is RLV
Residual lung volume = volume in lungs after maximum expiration
34
What is FVC
Forced Vital capacity = maximum volume expired after maximum inspiration
35
What is IC
Inspiratory capacity = maximum volume inspired following tidal expiration
36
What is the average IC for men and women
```
Men = 3600
Women = 2400
```
37
What is FRC
Functional residual capacity = volume in lungs after tidal expiration
38
What is the average FRC in men and women
```
Men = 2400
Women = 1800
```
39
During exercise what happens to EELV, IC, IRV and Te
EELV decreases
IC increases
IRV decreases
Te decreases
40
What is FEV1
Forced expiratory volume in one second (FEV1)
41
What does FEV1 –to-Forced vital capacity (FVC) ratio (FEV1/FVC) indicate
pulmonary airflow capacity
42
It reflects ____________ power and overall resistance to air movement in the lungs
It reflects pulmonary expiratory power and overall resistance to air movement in the lungs
43
Healthy individuals normally expel about ?% of the vital capacity in 1 second (i.e. FEV1/FVC ratio > ?%)
Healthy individuals normally expel about 85% of the vital capacity in 1 second (i.e. FEV1/FVC ratio > 85%)
44
Obstructive lung disease (e.g. COPD) reduced FEV1/FVC ratio; often values less than ?
Obstructive lung disease (e.g. COPD)
| Reduced FEV1/FVC ratio; often values less than 70%
45
in COP is there
more or less elastic recoil pressure
more or less expiratory low
LESS
46
what is the equation for minute ventilation (VE)
Minute ventilation = breathing rate (Vf) x tidal volume (Vt)
47
What are TPYICAL VE values at rest
VE = 12 (vf) x 0.5 (Vt) L= 6 L/min (typical value at rest)
48
During exercise what happens to Vf
Vf increases to 35 – 45 breaths/min (some elite endurance athletes breathe as rapidly as 60-70 breaths/min)
49
During exercise what happens to Vt
Vt of 2.0 L and higher occur during exercise
50
What happens to VE during exercise
VE may increase 100 L or more (about 17-20 x resting value)
51
VT for trained and untrained individuals rarely exceed ?% of VC.
60% of VC
52
What is Anatomical dead space
A portion of the air in each breath does not enter the alveoli and participate in the gaseous exchange with the blood
53
Anatomical dead space ranges between what in healthy individuals
Ranges between 150 – 200 mL in healthy individuals
54
Does the composition of dead space air remain identical to ambient air
yes
55
What is alveolar ventilation
the portion of inspired air reaching the alveoli and participating in gas exchange
56
What is the equation for dead space minute ventilation
Dead space minute ventilation = Dead space(ml) x Vf (ml/min)
57
What is the equation for VA
VA= VE (ml/min) – dead space minute ventilation (ml/min)
VA= (Vt*Vf )-(Dead space(ml) x Vf (ml/min))
58
What has a greater impact on VA
-Vf (shallow breathing) or Vt (deep breathing)
Vt
59
During exercise, VT encroaches on ?
During exercise, VT encroaches on IRV
60
Deeper breathing = alveolar ventilation increases from ?% of the total VE at rest to more than ?% of the exercise VE
Deeper breathing = alveolar ventilation increases from 70% of the total VE at rest to more than 85% of the exercise VE
61
With more intense exercise, the increase in VT plateaus approximately ?% of the VC; VE increases further through nonconscious increase in ?
With more intense exercise, the increase in VT plateaus approximately 60% of the VC; VE increases further through nonconscious increase in VF
62
What does hyperventilation refer to
Refers to an increase in VE that exceeds the O2 requirements and CO2 elimination needs of metabolism
63
hyperventilation lowers normal alveolar ? and causes excess ? to leave the body.
normal alveolar CO2 and causes excess CO2 to leave the body.
64
Does hyperventilation increase or decrease PH
Increases = respiratory alkalosis
65
What are some symptoms of hyperventilation
lightheadedness; prolonged hyperventilation leads to unconsciousness from excessive CO2 unloading
66
What is partial pressure
The molecules of each specific gas in a mixture of gases exerts their own partial pressure
67
What is The mixture’s total pressure
the sum of the partial pressures of the individual gases in the mixture
68
What is Daltons Law
Partial pressure = percentage concentration of specific gas x total pressure of gas mixture
69
What is the total pressure of ambient air
760 mmHg
70
What is the percentage of O2, CO2, and N in ambient air
```
O2 = 20.93
CO2 = 0.03
N = 79.04
```
71
What happens to the air what is passes down the respiratory tract
Air completely saturates with water vapor when it enters the nasal cavities and mouth and passes down the respiratory tract.
72
What is the pressure of water molecules in humidified air
47 mmHG
73
What is the PO2 in ambient air and tracheal air
```
Ambient = 159
Tracheal = 149
```
74
What are the partial pressures of O@, CO2, and N in alveolar air
14. 5% O2--> 14.5% x (760 – 47 mmHg) = 103 mmHg
5. 5% CO2 --> 5.5% x (760 – 47 mmHg) = 39 mmHg
80% N2 --> 80% x (760 – 47 mmHg) = 571 mmHg
75
There alveolar partial pressures measure molecules against what side of the alveolar-capillary membrane
These values represent average pressures exerted by oxygen and carbon dioxide molecules against the alveolar side of the alveolar-capillary membrane
76
Do these values remain physiologically constant
They DO NOT remain physiological constant; rather they vary slightly with ventilatory cycle and adequacy of ventilation (i.e. V/Q ratio)
77
What explains why the partial pressure of alveolar gases remains relatively stable
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
78
Two factors that govern the rate of gas diffusion into a fluid?
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
79
Pressure differential
Molecules move from an area of ___ pressure to an area of ____ pressure.
Molecules move from an area of high pressure to an area of low pressure.
80
In humans what creates the driving force for gas diffusion across the pulmonary membrane
The pressure difference between alveolar and pulmonary blood gases
81
How is gas solubility expressed
Gas solubility is expressed as mL of gas per 100 ml (dL) of fluid
82
What is the solubility coefficient for CO2, O2 and N
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
83
What is the equation to calculate the amount of gas dissolved in a fluid
solubility coefficient x (gas partial pressure / total barometric pressure)
84
How does the exchange of gases between the lungs and blood and gas movement at the tissue level progresses
passively by diffusion, depending on their pressure gradients
85
What is the PO2 and CO2 in the pulmonary artery and in the alveoli
From pulmonary artery:
PO2 = 40 mmHg;
PCO2 = 46 mmHg
In alveoli:
PO2 = 100 mmHg;
PCO2 = 40 mmHg
86
Alveolar gas-blood gas equilibrium takes place in about ? seconds, or within one-third of _________ time through the lungs
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
87
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
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
88
Does partial pressure in the lungs vary
very little
89
At rest, PO2 in the fluid immediately outside the muscle cell averages _____mmHg and intracellular PCO2 averages ____ mmHg
At rest, PO2 in the fluid immediately outside the muscle cell averages 40 mmHg and intracellular PCO2 averages 46 mmHg
90
Blood carries oxygen in what 2 ways
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
91
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
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
92
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
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
93
What does the oxygen content in physical solution establish and determine?
Establishes the PO2 of the plasma and tissue fluids
Determines oxygen loading of hemoglobin in the lungs and subsequent release in the tissues
94
Hemoglobin is carried within the ______ trillion red blood cells of humans
This concentration carried _____ times more oxygen than normally dissolved in plasma
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
95
280 million hemoglobin molecules “capture” and transport about _____ mL of O2 in each liter of blood
280 million hemoglobin molecules “capture” and transport about 197 mL of O2 in each liter of blood
96
What is the reversible hemoglobin reaction
Hb4 + 4 O2 ↔︎ Hb4O8
97
What dictates the oxygenation of hemoglobin to oxyhemoglobin
the partial pressure of oxygen dissolved in physical solution
98
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
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
99
What is the blood’s oxygen carrying capacity
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
100
What does 100% O2 saturation indicate (in the lungs)
100% saturation indicates that oxygen combined with hemoglobin = the oxygen-carrying capacity of hemoglobin (20 mL per dl of blood
101
What is the equation for % saturation
%saturation = (O2 combined with hemoglobin/O2 capacity of hemoglobin) x100
102
Below what pressure of O2 does the binned O2 decline (in the lungs)
60 mmHg (90% saturated wit oxygen) below this pressure, the quantity of oxygen combined with hemoglobin declines more rapidly
103
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.
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.
104
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.
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.
105
What does The arterio-mixed-venous oxygen difference describe
The arterio-mixed-venous oxygen difference (a-vO2 difference) describes the difference between the oxygen content of arterial blood and mixed-venous blood
106
What is the a-vO2 difference at rest
The a-vO2 difference at rest normally averages 4 to 5 mL of oxygen per dl of blood (20 – 15 = 5)
107
What does The large quantity of oxygen still attached to the hemoglobin provide
provides a reserve so cells can immediately obtain oxygen should metabolic demand suddenly increase.
108
What happens to the a-vO2 difference during intense exercise
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)
109
What is the Bohr effect
Any increase in plasma acidity and temperature causes the dissociation curve to shift downward and to the right
110
What does the Bohr effect indicate
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
111
What are the 3 factors during intense exercise causing the Bohr Effect
(1) metabolic heat, (2) carbon dioxide and (3) acidity from blood lactate accumulation
112
What compound do RBCs produce during glycolysis
Red blood cells produce the compound 2,3-diphosphoglycerate (2,3-DPG) during glycolysis
113
what does it do
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
114
during strenuous exercise what does it aid in
During strenuous exercise, 2,3-DPG aids in oxygen transfer to the muscles
115
What is myoglobin
Myoglobin is an iron-containing protein in skeletal and cardiac muscle fiber. It provides intramuscular oxygen storage
116
What is the difference btwn hemoglobin and myoglobin
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
117
What shape is the myoglobin cure
rectangular hyperbola
118
When does the quantity of O2 release from MbO2
when tissue PO2 declines below 5 mmHg
119
What is the equation for PACO2
PACO2 = VCO2 x (Pb –47) / VA
120
What is the equation for PAO2
PAO2=PiO2 - PaCO2/(VCO2/VO2)
121
What is Pb
Pb = barometric pressure (760 mmHg)
122
What is PiO2
PiO2 = inspired PO2 (20% x (760-47 mmHg)
123
What 2 factors control ventilation
1. Neural
| 2. Humoral
124
What are the humoral factors
1. Plasma PO2 and peripheral chemoreceptors
| 2. Plasma PCO2 and H+ concentration
125
What 2 factor regulate ventilation during exercise
1. Chemical control
| 2. Nonchemical control
126
Inspiratory and expiratory neurons are located within the medial portion of the ?
Medulla
127
Where are the neurons that leads to inspiration located
Dorsal respiratory group (DRG)
128
Is The nervous signal that is transmitted to the inspiratory muscles instantaneous bust of AP?
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.
129
Where are Most of the neurons in the DRG are located
nucleus tractus solitaris (NTS)
130
the nucleus tractus solitaris (NTS)
| Receives feedback signals from?
peripheral chemoreceptors,
baroreceptors
receptors in the lungs (via vagal nerve afferents)
131
At rest what exerts the greatest control of pulmonary ventilation
The chemical state of the blood
132
Chemoreceptors detect?
Chemoreceptors detect changes in the O2 in the blood, and to a lesser extent CO2 and H+
133
Where are peripheral chemoreceptors located
located in the: carotid bodies and aortic bodies
134
Where are the carotid bodies located and what nerve is used to relay info
Located at the bifurcation of the common carotid arteries monitor blood before it enters brain
Relay information via glossopharyngeal nerve to the DRG
135
Where are the Aortic bodies located and what nerves relays info
Aortic bodies
Located along the arch of the aorta
Relay information via the vagus nerve to the DRG
136
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)
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)
137
Does CO2 and H have an effect on peripheral chemoreceptors?
CO2 and H+ more powerful in central chemoreceptors
| However, stimulation of peripheral chemoreceptors by CO2 and H+ occurs 5x faster than central chemoreceptors
138
What rest what provides the most important respiratory stimulus
At rest arterial PCO2 in plasma
139
Does CO2 have a direct or indirect effect on central chemoreceptors
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.
140
Is the BBB permeable to H ions
No
141
Why are PO2 values in carotid body and aortic body = arterial PO2
** extreme blood flow at the carotid and aortic bodies.
Virtually no O2 extracted from blood
Therefore, PO2 values in these regions = arterial PO2
142
Where does the stiumuls to breathe come from in breath holding
The stimulus to breathe comes from increases arterial PCO2 and H+
143
What happens when u hyperventilate before breath holding
alveolar air composition becomes more like ambient air
You have less CO2 in lungs, so it takes longer for it to accumulate
144
What is metabolic acidosis
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
145
What is buffering
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)
146
What is an example of a chemical buffer
Bicarbonate buffer: carbonic acid (weak acid) and sodium bicarbonate (salt)
147
What happens in the muscle blood to the lungs
Lactic acid --> Lactate + H+ --> NaHCO3 (sodium bicarbonate) ↔︎ Sodium lactate + H2CO3 ↔︎ H2O + CO2
148
What represents 70% of bloods buffering capacity
Bicarbonate buffer
149
What is the general equation for the bicarbonate buffer
co2+h2o h2co3 hco3 +h
150
What are physiological buffers
what 2 systems provide the second line of defence
the pulmonary and renal systems present the second line of defence .
Their buffering function occurs only when a change in pH has already occurred
151
What is the ventilatory buffer
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
152
What is the renal buffer
Excretion of H+ by the kidneys, although relatively slow, provides an important longer-term defense that maintains the body’s buffer reserve
153
At what exercise intensity does the HLA production exceed buffers ability to decrease H
greater than or equal to 50-70%
154
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
TRUE lol
| ie minute ventilation does not change much during mod exercise
155
During strenuous exercise what causes the additional ventilatory stimulous
large anaerobic component (lactate accumulation), increase CO2 and H+ provides additional ventilatory stimulus
The resulting hyperventilation reduces alveolar and arterial PCO2
156
Describe ventilation in steady rate exercise
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)
```
157
What happens to VE during intense sub maximal exercise
VE moves sharply upward and increases disproportionately in relation to VO2.
158
What is ventilatory threshold
The point at which VE increases disproportionately with VO2
marked increase in VE/VO2 ratio
159
What stimulates ventilation that increases VE/VO2 in intense exercise
The excess CO2 released from buffering reaction
160
Conceptually, what does the LT represent
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
What are the 3 different indicators or LT
1. Fixed blood lactate concentration
2. Ventilatory threshold
3. Blood lactate-exercise VO2 response
162
What is the immediate response of the respiratory system at high altitudes
- Hyperventilation
| - Body becomes more alkaline due to reductions of co2
163
What is the longer terms effect of the respiratory system at high altitues
- Hyperventilation
| - Excretion of base HCO3 via the kidney leading to a reduction in alkaline reserve and restoring normal PH
164
What is the equation for velocity of blood flow
Velocity of blood flow (v) = Blood flow (F)/Vascular cross-sectional area
v in aorta>arteries>>>capillaries
165
Describes the valves in the veins
- 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
What is MAP
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
What happens to ur arteries during resistance exercise
Arterial vascular compression: increases total peripheral resistances and reduces muscle perfusion
168
What happens In an attempt to restore muscle blood flow
Muscle blood flow decreases proportionally to the % of maximum force capacity exerted
increase in sympathetic nervous system to increase Q and MAP
169
During stead rate exercise there is rhythmic muscular contraction and vasodilation occurs; what effect does this have on TVR
vasodilation in the active muscle --> reduces TVR --> blood flow enhanced
170
As exercise continues does SBP change?
systolic pressure declines (diastolic blood pressure remains unchanged)
because the arterioles in the active muscle continue to dilate --> reducing TVR
171
What happens to systolic BP during graded exercise?
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
What elevated BP more: exercising the LB or UP
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
Summarize the AP in SA node
?
174
What are the 5 steps of the excitatory and conductive system of the heart
1. An action potential is initiated in the SA node and travels by way of conduction fibers to the AV node. Action potential spreads throughout the cells of the atria.
2. Impulse arrives at the AV node where there is a momentary delay because 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 the atrioventricular bundle (bundle of His) in the interventricular septum.
4. Atrioventricular bundles only travels a short distance before splitting into right and left bundle branches.
5. Impulse travels to the myocardial cells of the ventricle by means of an extensive network of conduction fibers called Purkinje fibers.
175
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)
SA node - AV node - Delay - AV bundle of his - interventricular septum - right and left bundle branches - Purkinje fibers
176
Where do sympathetic nerves that control the heart emerge from and what do they synapse with
emerge from the upper thoracic regions of the spinal cord and synapse with post ganglionic neurons in the sympathetic trunk
177
What are the major hormones/NT that control the sympathetic activity of the heart and what are the receptors
Norepinephrine or epinephrine
ß1 receptors
178
In the SA nodes what happens when NE binds to ß1 receptors
open funny channels and Ca2+ channels
179
What happens when funny channels and Ca2+ channels open in the SA node
This will increase pacemaker potential --> shorter time to reach threshold potential
Accelerating self-excitation and increasing HR
180
What happens in the AV node
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
This increased HR is what type of effect
Chronotropic
182
What is considered tachycardia
heart rate above 100 bpms
183
During tachycardia what happens to the AP btwn the SA and AV node
Reduces time of AP propagation between SA and AV node = reduced time between atrial and ventricular contraction
184
What is the ionotropic effect
Increases atrial and ventricular contraction (** increased Ca2+ permeability = stronger muscular contraction)
185
What is the Starling effect
1. As the length of the muscle fiber is increased the muscle fiber comes closer to its optimum length for contraction.
2. The stretching of the muscle fiber increases the affinity of troponin for calcium which increases the crossbridge cycling.
186
Can venous return affect the SV
Increased sympathetic activity to the venous system-->vasoconstriction --> increase venous pressure --> decrease the capacity of the venous system to hold blood
187
How does sympathetic innervation also affects blood flow
Norepinephrine --> released by adrenergic fibers -->vasoconstrictor
188
Adrenergic fibers contribute to the vasomotor tone, which is?
adrenergic constrictor nerves are active even while at rest
Sympathetic activity to veins --> venoconstriction -->increases venous return
189
What does vasodilation do to adrenergic activity
It decreases it
190
What nerve is associated with the parasympathetic control of the heart and where does it emerge from
Vagus nerve emerges from the medulla (pre and post ganglionic nerves)
191
What are the receptors and what is the NT
Nicotinic receptors (pre-ganglionic) and muscarinic receptors (post ganglionic)
Ach
192
What happen in the SA node when there is Ach
In the SA node, Ach binding to muscarinic receptors opens K+ channels --> hyperpolarization (-65 to -75 mv)
193
What is there term when there is Reduced rate of rhythmicity in the SA node (decrease HR)
(bradycardia)
194
If the vagal tone is strong enough what can happen to the SA node
it’s possible to completely stop the rhythmical self-excitation of this node
195
When does central commend: feed-forward operate
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
What type of afferents relay information from the muscle to the cardiorespiratory center
Type III and IV afferents relay information from the muscle to the cardiorespiratory center.
197
What us a chemo receptor in the muscle
Chemoreceptors:
monitor the chemical state of the muscle
Metaboreflex: metabolite activation of type III and IV afferents
198
What is a mechanoreceptor in the muscle
monitor the physical state of the muscle
Mechanoreflex: increase activation of mostly type II afferents in response to increase stimulation of mechanosensitive receptors
199
What does the central command feedforward to the heart during exercise
The heart rapidly “turns on” during exercise by decreasing parasympathetic inhibitory input and increasing stimulating input from the brain’s central command.
200
Is sympathetic contribution triggered by the central command?
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
What are the initial stimuli, physiological responses and results of the factors affecting stroke volume
1. initial stimulus:
increase in sympathetic nerves to the heart
Decrease of parasympathetic nerves to the heart
2. Physiological response:
Increase in stroke volume from sympathetic nerves
increase in HR from symp and dec in para sym
3. Result:
inc in cardiac output
202
What happens to blood flow at the onset of exercise in active muscles and non active muscles
Vascular component of active muscle increases by dilation of local arterioles
Nonactive tissue constrict (e.g. renal area
203
What are the 2 factors that contribute to reduced blood flow to NON active tissues
1. Increased sympathetic nervous outflow (vasoconstriction)
| 2. Local chemicals that directly stimulate vasoconstriction or enhance the effect of other vasoconstrictors
204
Does Skeletal muscle blood flow closely couple to metabolic demand
yes
205
At rest, only every ___-___ capillaries in the muscle tissue remains open
30-40
206
What 3 factors occurs when dormant capillaries open =
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
Blood flow during exercise: Factors within active muscle:
Vasodilation occurs from _____ related to tissue ______
Vasodilation occurs from local factors related to tissue metabolism
208
Decrease in tissue O2 leads to ?
potent local stimulus for vasodilation in skeletal and cardiac muscle
209
CO2, H+, K+ and nitric oxide (NO) is released by _____ to contribute to vasodilation
by endothelial cells lining the blood vessels
210
Local regulation--> strong control of blood flow to maintain __?
adequate regional blood
211
What is the chain of reactions starting with an increase in tissue metabolism for factors within active muscles
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
What happens to CO during light to mod aerobic ex at the start and steady state
Start:
increase: due to inc in SV and HR
Steady State:
Plateau: cardiorespiratory system is able to meet metabolic demand
213
What happens to SV during light to mod aerobic ex at the start and steady state
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
What happens to HR during light to mod aerobic ex at the start and steady state
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
What happens to CO during MAXIMAL aerobic ex at the start and steady state
Start:
Increase: this is due to increase in SV and HR
High intensity:
Increases: SV will plateau, but HR will continue to increase
216
What happens to SV during MAXIMAL aerobic ex at the start and steady state
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
What happens to HR during MAXIMAL aerobic ex at the start and steady state
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
What happens to SBP during MAXIMAL aerobic ex at the start and steady state
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
What happens to DBP during MAXIMAL aerobic ex at the start and steady state
Start:
No change: due to peripheral vasodilation (facilitates blood flow to the working muscle)
High intensity:
No change
220
What happens to TVR/TPR during MAXIMAL aerobic ex at the start and steady state
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
What is the Fick method/equation for measuring CO
CO = {VO2 ml/min}/{avO2 diff ml/100ml blood}
| X100
222
What is the main difference in CO during exercise between untrained and trained
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
What are the 3 physiologic mechanisms that increase the hearts SV during exercise
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
What contributes to the enhances diastolic filling
During exercise:
Venous return increases
End-diastolic volume increases (preload)
Stretches ventricles in diastole: produce a more forceful ejection stroke
225
What contributes to greater systolic emptying
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
During exercises what contributes to the Cardiovascular Drift?
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
The cardiovascular shift occurs happens especially when?
especially during high ambient temperature
High body temperature: blood redistributed to skin: decrease in ventricular filling pressure and stroke volume
228
Exercise oxygen consumption (a-v O2 diff) increases by what two mechanisms:
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
What is the difference btwn the a-vO2 differ at rest and during exercise
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
What happens to the hematocrit when you exercise (sweat)
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
What happens to heart size with endurance training
Cardiac muscle mass and ventricular volume increase - cardiac hypertrophy (‘athlete’s heart’)
232
What happens to SV with endurance training
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
What happens to HR with endurane training
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
What happens to CO with endurance training
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
What happens to BF with endurance training
Increased capillarization
Greater recruitment of existing capillaries
More effective blood flow redistribution
Increased total blood volume
236
What happened to BP with endurance training
No significant change
237
What happens to BV with endurance training
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
What is the role role of Ca in the muscles fiber?
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
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
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
What contains the binding site for the ATP molecule
The myosin head
241
What enzyme is located on the myosin head
adenosine triphosphatase
242
How long does muscle contraction last
continues as long as calcium is available in the sarcoplasm
243
At the end of the contraction where is calcium pumped
calcium is pumped back into the SR, where it is stored until a new AP arrives at the muscle fiber membrane
244
Is energy required for both the contraction and relaxation phase?
YES
Calcium returned to SR by active calcium-pumping system --> requires AP
Therefore, energy is required for both the contraction and relaxation phase
245
Are type 1 fibers fast or slow twitch - how long does it take to reach peak tension
SLOW
100 ms
246
Are type 2 fibers fast or slow twitch - how long does it take to reach peak tension
Fast
50ml
247
What are the different types of type 2 fibers and which is most frequently recruited
Type II a = most frequently recruited
Type II x and Type II c
248
Which fiber type is better for aerobic
Type 1
249
Which fiber type is better for anaerobic
Type II
250
How does type 1 and type 2 differ in ATP production
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
Which type is beneficial for high aerobic endurance
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
Which type is better suited for short high intensity sprints
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
Generally, how is muscle fiber type determined
genetically determined, changing little from childhood to middle age
254
After innervation is established, how do muscle fibers differentiate?
according to the type of alpha-motor neuron that stimulates them.
255
What is fiber type shifting in COPD patients
COPD patients shift from type 1 to type 2
256
What is the principle of orderly recruitment
As the intensity of an activity increases, the number of fibers recruited increases:
Type I - type II a - type IIx
257
What mechanism explains the principle of orderly recruitment
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
What are concentric contractions considered and what happens to the filaments
the thin filaments are pulled towards the center of the sarcomere
joint movement is produced
concentric contractions are considered dynamic contractions
259
What kind of muscle contraction occurs when no joint movement is produced
Static or isometric muscle contraction
muscle generate force, but its length remains static (unchanged)
260
What is an eccentric contraction
muscles can exert a force even when lengthening
joint movement occurs also a dynamic contraction
261
What 4 facotrs influence force generation
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
What is the effect of motor units and muscle size on force generation
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
What is the effect of Frequency of stimulation of the motor units: rate coding on force generation
A single motor unit can exert varying levels of force depending on the frequency at which it is stimulated
264
What is a twitch
smallest contractile response of a muscle fiber or a motor unit to a single electrical stimulus
265
What is summation
series of stimuli in rapid sequence prior to complete relaxation elicit an even greater increase in force or tension
266
What is tetanus
when Continues stimulation--> tetanus--> peak force or tension of the muscle fiber or motor unit
267
Does sarcomere length affect muscle force
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
How does contraction speed affect force generation
during concentric contraction --> maximal force decreases as speed increased
269
What is a nerve impulse
electrical signal arises when a stimulus is strong enough to change the normal electrical charge of the neuron
270
What is the resting membrane potential
-70 mv
271
is the cell membrane more permeable to K or NA
K
272
What does the NA/K pump do
maintains the imbalance by actively transporting K+ in and Na+ out
more +ve charged ions outside the cell vs. inside
273
What is an action potential
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
What is a threshold
the membrane voltage at which a graded potential becomes an AP
All-or-none principle
275
What is an absolute refractory period
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
What is a relative refractory period
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
Is a myelinated axon fatty
yes
278
myelin sheath is formed by specialized called called the ?
Schwann cells
279
What is a node of ranvier
has gaps between the adjacent Schwann cells
leaving the axon uninsulated at these points
280
What is saltatory conduction
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
what is the relationship between nerve diameter and impulse speed
Neurons of larger diameter conduct nerve impulses faster than neurons of smaller diameter
large neurons present less resistance to local current flow
282
What is a synapse and what are the 2 different types
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
what is the main NT for motor neurons and parasympathetic neurons
Ach
284
What are adrenergic nerve and what are cholinergic nerve
Nerves that release norepinephrine: adrenergic nerves
Nerves that release Ach: cholinergic
Ach and NE can be either excitatory or inhibitory
285
Where does summation of AP's occur
at the axon hillock
286
What is the difference btwn spatial and temporal summation
Spatial: simultaneous stimulation by several presynaptic neurons
Temporal: high frequency stimulation by one presynaptic neuron
287
What are the right and left cerebral hemispheres connected by
corpus callosum
288
The cerebral cortex consists of what portions of the brain
outer portion (grey) unmyelinnated
289
the cerebral cortex is the site of mind and intellect, allows people to ?
Think, and be aware or sensory stimuli - conscious brain
290
What are the 5 lobes of the cerebrum
1. Frontal
2. temporal
3. Occipital
4. Parietal
5. Insular
291
What is the frontal lobe responsible for
general intellect and motor control (primary motor cortex located here)
292
What is the temporal lobe responsible for
auditory input and interpretation
293
What is the parietal lobe responsible for
general sensory input and interpretation (primary sensory cortex located here)
294
What is the occipital lobe responsible for
visual input and interpretation
295
What is the insular lobe responsible for
diverse functions, usually linked to emotion and self-perception
296
What is the primary motor cortex responsible for
the control of fine and discrete muscle movement
297
What are the neurons known as in the PMC
pyramidal cells: conscious control of skeletal muscles
298
Cell bodies in the primary motor cortex and their axons form the ?
extrapyramidal tracts
Provide the major voluntary control of skeletal muscle
299
Where is the premotor cortex located and what is it responsible for
Anterior to the precentral gyrus in the frontal lobe
Learned motor skills of repetitious or patterned nature are stored here
300
what part of the brain is considered the memory bank
Premotor cortex
301
What is the diencephalon composed of
the thalamus and hypothalamus
302
The thalamus is the integration center for what
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
What is the hypothalamus responsible for
responsible for maintaining homeostasis by regulating all processes that affect the body’s internal environment
(bp, resp, temp, appetite)
304
The cerebellum is important in ?
coordinating movement
305
how does the cerebellum assist the PMC
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
Where is the reticular formation located and what is it
Collection of neuron in the brainstem
307
What is it responsible for
Integrates various incoming and outgoing signals
These signals originate from the stretching of sensors in joints and muscles, and other receptors
308
The brain stem:
Coordinate ________ function
Maintain ______ tone
Control cardiovascular and ______ function
Determine state of _______ (arousal and sleep
Coordinate skeletal muscle function
Maintain muscle tone
Control cardiovascular and respiratory function
Determine state of consciousness (arousal and sleep
309
What provides the major conduit for the two-way transmission of information from the skin, joints, and muscles to the brain.
the spinal cord
310
What describes the limbs of this core
The ventral (anterior) and dorsal (posterior)
311
the SC contains what 3 types of neurons
```
motor neurons (ventral),
Sensory neurons (dorsal), interneurons.
```
312
What are the 5 types of receptors that the sensory division receives info from
1. mechanoreceptors
2. thermoreceptors
3. nociceptors
4. photoreceptors
5. chemoreceptors
313
Mechanoreceptors respond to:
mechanical forces (pressure touch vibration or stretch)
314
Thermoreceptors respond to:
changes in temperature
315
Nociceptors respond to
painful stimuli
316
Photo receptors respond to:
electromagnetic radiation (light) to allow vision
317
Chemoreceptors respond to:
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
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)
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
Where are sensory impulses integrated that terminate in the SC?
Sensory impulses that terminate in the spinal cord are integrated there
320
Sensory signals that terminate in the lower brain stem and cerebellum result in ?
subconscious motor reactions of a higher and more complex nature than simple spinal cord reflexes
321
Sensory signals that terminate at the thalamus begin to enter the level of?
consciousness, and the person begins to distinguish various sensations
322
Only when sensory signals enter the ________ can one discretely localize the signal.
Only when sensory signals enter the cerebral cortex can one discretely localize the signal.
323
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:
1. The spinal cord
2. The lower regions of the brain
3. The motor area of the cerebral cortex
324
What is a muscle spindle
What does it consist of
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
The intrafusal fibers are controlled by specialized motor neurons, referred to as ?
γ-motor neurons (or gamma motor neurons)
326
Approximately _____ muscle fibers are usually connected with each Golgi tendon organ.
5 to 25
327
Golgi tendon organs are sensitive to ____ in the muscle–tendon complex
tension
328
These sensory receptors are _____ in nature, performing a protective function by reducing the potential for injury
These sensory receptors are inhibitory in nature, performing a protective function by reducing the potential for injury
329
When golgi tendons are stimulated, these receptors inhibit the ____ muscles and excite the ______ muscles.
inhibit the contracting (agonist) muscles and excite the antagonist muscles.
330
What 3 things does the endocrine system include
1. Consists of a host organ,
2. minute quantities of chemical messengers (hormones)
3. target receptor (organ)
331
What is the difference between and endocrine and an exocrine gland
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
Steroid-derived hormones
Soluble in blood plasma?
Receptor location?
Response to ___________ binding: activates genes for transcription and translation
E.g.: ?
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
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
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
What does cyclic AMP do?
Binding of a hormone with its specific receptor in the plasma membrane --> alters cell permeability to a particular target OR activates intracellular substances
335
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
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
What 3 factors affect the first steps in initiating hormone action
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
What is upregulation and down regulation
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
A hormone increases enzyme activity in what three ways
1. Stimulate enzyme production.
2. Combines with the enzyme to alter its shape and ability to act
3. Activates inactive enzyme forms
339
Give an example of stimulating enzyme production
steroid hormones --> direct gene activation --> protein synthesis (proteins for growth and repair, enzymes that have numerous effects on cellular processes
340
What is it called when hormones combine with the enzyme to alter its shape and ability to act
allosteric modulation: increases or decreases the enzyme’s catalytic effectiveness.
341
Four factors determine plasma concentration of a particular hormone
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
How does Rate of either catabolism or secretion into the blood determine concentration of a hormone
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
How do Plasma volume changes During prolonged exercise affect hormone concentration
plasma volume decreases: increase in plasma hormone concentration, even without an absolute change in hormone amount.
344
What 3 factors stimulate endocrine activity
1. Hormone stimulation
2. Humoral stimulation
3. Neuron stimulation
345
What is hormone stimulation
When hormones influence secretion of other hormones
346
What is humoral stimulation
Changing levels of ions and nutrients in the blood, bile and other body fluids stimulate hormone release
ex: increase in blood sugar
347
What is neural stimulation
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
The pituitary gland secrets 6 ?
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
What is Secrets proopimoleanocortin (POMC)
precursor molecule of other active molecules
| ACTH, melanocortin peptides and beta-endorphins
350
Growth hormone-releasing factor from the _____________ influences resting growth hormone (GH) secretion by directly stimulating the ____ pituitary gland
Growth hormone-releasing factor from the hypothalamus influences resting growth hormone (GH) secretion by directly stimulating the anterior pituitary gland
351
What does GH promote
promotes cell division and cellular proliferation through the body
352
GH facilitates protein synthesis in what three ways
1. Increasing amino acid transport through the plasma membrane
2. Stimulates RNA formation
3. Activating cellular ribosomes that increase protein synthesis
353
What happens to GH secretion during EX
MORE
354
What is the effect of the extra GH
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
What are the peptide messengers produced in the liver as a result of increased GH
insulin-like growth factors IGF-1 and IGF-II
356
what are IGFS
mediate many of GH’s effects.
In response to GH stimulation
binding proteins within muscle, nutritional status, and plasma insulin levels.
357
What does thyrotropin (TSH) control
hormone secretion by the thyroid gland and maintains growth and development of the thyroid gland
358
ACHT :
enhances _____ mobilization from the adipose tissue
increase ____genesis
stimulates _____ catabolism
ACHT:
enhances fatty acid mobilization from the adipose tissue
increase glycogenesis
stimulates protein catabolism
359
PRL levels________ at high exercise intensities and return toward baseline within __ min during recovery
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
What are the 2 gonadotropic hormones that stimulate male and female sex organs to grow
FSH and LH
361
what does FSH do
Initiates follicle growth in the ovaries = secretion of estrogen
362
what does LH do
complements FSH action: causes estrogen secretion and rupture of the follicle = ovum pass through the fallopian tube for fertilization
363
What do they do in males
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FSH = stimulates germinal epithelium growth in the testes and promotes sperm development.
LH = stimulates the testes to secrete testosterone
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364
What 2 hormones are stored in the post pit
| produced in hypothalamnus
ADH and oxytocin
365
Under influence of TSH produced by the anterior pituitary gland
Release _______(calcium-regulating hormone)
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Release ______ (T4) and _________ (T3)
T3 is the active form of thyroid hormone
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Release calcitonin (calcium-regulating hormone)
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Release thyroxine (T4) and triiodothyronine (T3)
T3 is the active form of thyroid hormone
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366
What does T4 stimulate
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
Does exercise increase T4
yes by 35%
368
What does T3 facilitatte
neural reflex activity
369
What are the 4 effects of hyperthyroidism
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
What are the 4 effects of hypothyroidism
1. Reduced metabolic rate and cold intolerance from reduced internal heat production
2. Decreased protein synthesis produces brittle nails, thinning hair, and dry, thin skin
3. Depressed reflex activity, slow speech and thought processes, and feeling of fatigue (in infancy causes cretinism, marked by decreased mental capacity)
4. Slow heart rate (bradycardia)
371
What does the adrenal medulla secrete
Prolongs sympathetic effects by secreting epinephrine and norepinephrine (collectively called catecholamines)
EPI = 80% of secretions
Stimulates glyogenolysis
372
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.
Norepinephrine increases markedly at intensities that exceed 50% VO2 max
Epinephrine levels remain unchanged until exercise intensity exceeds 60% level
373
The adrenal cortex is stimulated by what hormone from where
stimulated by corticotropin from anterior pituitary to release adrenocortical hormones
374
What do mineralocoticoids regulate
minerals: salt sodium and K+ in the extracellular fluid
375
What does aldosterone the mineraocoticoid do
Stimulates Na+ reabsorption along with fluid in the distal tubules of the kidneys by increasing synthesis of sodium transporter proteins
376
Is the renin-angiotensin mechanism increased or decreased during sympathetic stimulation during exercise
increased
377
Where is renin secreted from and where
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
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 _____
Glucocorticoids = corticotropin-releasing factor from the hypothalamus causes release of ACTH from the anterior pituitary = promotes release of glucocorticoid by the adrenal cortex
379
Cortisol = major ____ of the adrenal ____
Cortisol = major glucocorticoid of the adrenal cortex
380
What happens to cortisol output with exercise intensity
cortisol output increases with exercise intensity; this heightened output accelerates lipolysis, ketogenesis, and proteolysis.
381
Testosterone = most important __________ secreted by the ________ initiates sperm production and development of male secondary sex characteristics
Testosterone = most important androgen secreted by the testes initiates sperm production and development of male secondary sex characteristics
382
Ovaries provide the primary source of?
estrogens, estradiol and progesterone
Regulates ovulation. menstruation and physiological adjustments during pregnancy
383
Testosterone ad swimming
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
What is type 1 diabetes
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
What 3 factors can produce high blood glucose in type 2 diabetes
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
What is the relationship between insulin release and physical activity intensity
As intensity increases, there is a decreases in insulin secretion
387
Prolonged physical activity derives progressively more energy from ___________ from the adipocytes from reduced insulin output and decreased carbohydrate reserves.
Prolonged physical activity derives progressively more energy from free fatty acids mobilized from the adipocytes from reduced insulin output and decreased carbohydrate reserves.
388
What does glucagon stimulate
primarily stimulates both glycogenolysis (with adenylate cyclase) and gluconeogenesis(amino acid uptake) by the liver and increases lipid catabolism.
389
What does GH stimulate and what happens in trained ppl
Growth hormone (GH) stimulates lipolysis and inhibits CHO breakdown
Trained individuals less rise in blood GH levels at any given physical activity intensity
390
What does ACTH stimulate and what happens in trained individuals
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
What happens to FSH, LH and Testosterone in trained individuals
Decrease in reproductive hormone responses in men and women.
Male endurance athletes decrease in testosterone levels, but LH and FSH remain stable
392
What is the effect of ADH in trained individuals
no diff
393
What happens to T4 in trained individuals
over production of T3 and T4 however, no evidence indicates a inordinately high BMR levels
394
What happens to aldosterone in trained individuals
no change
395
What happens to cortisol in trained individuals
cortisol levels increase less in trained vs. untrained individuals who perform the same absolute level of submaximal exercise
396
What happens to NE and EP in trained individuals
sympsubmaximal workload remains lower in trained vs. untrained.
athoadrenal activity in response to absolute
397
What happens in insulin and glucagon in trained individuals
trained state requires less insulin and glucagon at any stage from rest through light to moderately intense physical activity
