exam 3 (final)

functions of the respiratory system

\-maintain a constant O₂ & CO₂ in blood

\-acid-base balance

\-provides a means of gas exchange b/n the environment & the body

ventilation

process of moving air in & out of lungs

respiration

ventilation & exchange of gases in lungs

internal respiration

at the cell

external respiration

at the lung

conducting zone

\-10% of total lung volume

\-air passed to the alveoli

\-anatomical dead space

\-nose, trachea, carina

respiratory zone

\-90% of total lung volume

\-where gas exchange (O₂ & CO₂) occurs

\-alveolar ducts & capillaries

nose

\-warms, humidifies & filters air (air conditioning)

\-100% humidified (47 mmHg at body temp)

trachea

\-surrounded by cartilage

\-high resistance to airflow, slows done air

carina

\-at base of trachea

\-primary coughing reflex

type 1 alveoli

1 layer of epithelial cells

type 2 alveoli

surfactant secreting

surfactant

\-lines surface of alveoli

\-liquid containg lipoproteins

\-↓ surface tension of alveolar membranes

\-gives lungs good compliance

compliance

\-change in volume for a change in pressure

\-reason why we can inflate & deflate our lungs easily

O₂ cost of breathing

at rest= 6 mLO₂/min

inspiration at rest

diaphragm pulls down, lungs are expanded (active)

expiration at rest

diaphragm relaxes, lungs passively recoil

muscles of inspiration (exercise)

\-pulls ribs up: scalenes & sternoclridomastoid

\-pulls ribs out: external intercostal

\-diaphragm

muscles of expiration (exercise)

\-pulls ribs down & in: internal intercostal

\-external oblique, rectus abdominis, internal oblique, transverse abdominis (abdominals push diaphragm up)

gas diffusion

moves from areas of high to low pressure

sites of gas diffusion in the body

\-alveoli-capillary interface

\-tissue-capillary interface

factors that affect gas exchange

↑ gas solubility, ↑ pressure gradient, ↑ diffusion space, ↑ surface area

Fick

Hartog Hamburger

gas solubility

\-positively related

\-how easily gas can dissolve into environment

pressure gradient

\-positiviely related

\-biggest driver of oxygen, high to low pressure

diffusion space

\-inversly related

\-tissue thickness

\-connection with cells of capillaries & alveoli, want it to be very thin

surface area

positively related

ficks law of diffusion

\-R= rate pf gas exchange

\-D= solubility constant

\-A= surface area

\-∆p= difference in pressure gradient between capillaries & alveoli

\-d= diffusion space/tissue thickness

atmospheric gas fractions at sea-level

\-O₂= 0.2093

\-CO₂= 0.0003

\-N₂= 0.7904

change in atmospheric pressure

\-↑ altitude= ↓ pressure

\-due to gravity which causes gas molecules to be close to the ground

alveolar partial pressure of gases

\-O₂= 0.146

\-CO₂= 0.056

O₂ transport in blood

1)dissolved in blood

\-3 mLO₂/L blood dissolved

\-low dissolvability of O₂

\-1.5%

2)bound to hemoglobin

\-binds & carries O₂

\-1.34 mLO₂/ gm Hb (when fully saturated)

\-98.5 %

hemoglobin

\-250 million Hb or 1 RBC

\-binds 4 O₂ molecules

\-men= 150 g Hb/L blood

\-women= 130 g Hb/L blood

\-1 g Hb can combine w/ 1.34 mLO₂

arterial-venous O₂ difference

\-(a-v)O₂

\-diffencene b/n CaO₂ & CvO₂

\-amount of O₂ extracted by tissue

Fick equation VO₂

\-(HR×SV)×(a-v)O₂ diffencene

\-illustrated the factors determining VO₂

CO₂ transport

1)dissolved in plasma (10%)

2)bound to Hb (20%)

3)formed as HCO₃ on RBC (70%)

bicarbonate-CO₂ transport system

\-CO₂ + H₂O→H₂CO₃→H⁺ + HCO₃⁻

\-Cl⁻ shift/ Hamberger shift

rest-to-work transitions

1)rapid ↑ in ventilation

\-proportional to intensity

2)rapid ↑ in pulmonary blood flow

3)airway dilation & ↓ resistance to air flow

\-bronchioles

ventilatroy control during submax exercise

\-higher brain center (primary drive to increase ventilation during exercise)

\-chemoreceptors (↑ pCO₂ & ↓ pH) & mechanoreceptors (muscular movement)

\-respiratory muscles (↑ ventilation)

\-peripheral chemoreceptors carotid/aortic (↓ pO₂, ↑ pCO₂ & ↓ pH)

\-↑ temp & catecholamines

ventrilation: incremental exercise

\-sharp rise in Vε

\-motor recruitment pattern

\-propriceptive input

\-↑ acidosis

\-↑ body temp

\-↑ epi/ne

anterior pituitary hormones

\-thyroid stimulating hormone (TSH)

\-adrenocorticotropin hormone (ACTH)

\-LH & FSH (act on ovaries, regulate menstration)

\-growth hormone

\-prolactin (milk production when pregnant)

growth hormone (GH)

\-signal for release: exercise & hypoglycemia

\-acts on muscle, adipose, & liver

\-releases from anterior pituitary

\-essential for normal growth

\-stimulated protein synthesis & bone growth

\-decreases glucose uptake into muscle

\-increases lipolysis

\-stimulates gluconeogenesis in liver

anti-diuretic hormone

\-released from posterior pituitary

\-signal for release: sweating or dehydration & ↑ plasma osmolality

\-acts on kidney (collecting duct)

\-↑ H₂O reabsorption

\-maintain plasma volume

osmolality

\-decreased water in plasma

\-concentration of solutes

adrenal medulla

\-part of the SNS

\-secretes catecholamines (epi/ne)

adrenal cortex

\-secretes steroid hormones

\~mineralocorticoids: aldosterone, corticosterone, deoxycorticosterone

\~glucocorticoids: cortisol

\~androgens

aldosterone

\-releases from adrenal cortex

\-signal for release:

\~decreased blood volume/pressure

\~decreased plasma sodium

\~angiotensin II: potent vasoconstricter

\-acts on kidney (distal convoluted tubule)

\-actions:

\~maintain plasma Na⁺ & volume

\~↑ H₂O reabsorption

\~BP regulation

\~stimulate thirst

erythropoietin (EPO)

\-released from the kidney

\-signal for release: hypoxia, anemia, & blood loss

\-ergogenic aid alert

\-action: stimulates RBC production

insulin

\-released from pancreas (β cells)

\-signal for release: ↑ BG & AA’s in blood

\-acts on muscle & adipose

\-actions:

\~untake of FFA’s, AA, & glucose

\~inhibits gluconeogenesis, lypolysis, & protein breakdown

glucagon

\-released from the pancreas (α cells)

\-signal for release: ↓ BG/AA’s in blood & prolonged exercise

\-acts on liver

\-actions:

\~↑ gluconeogenesis & glycogen breakdown

\~↑ lypolysis & protein breakdown

\~inhibits TG & glycogen synthesis

epi/norepi

\-released by adrenal medulla

\-↑ linearly with exercise

\-acts on liver, muscle, & adipose

\-actions: ↑ lipolysis, gluconeogenesis in liver, & glycogenolysis in muscle

athletic amenorrhea

\-FSH & LH have altered release from pituitary

\-↓ estrogen

\-causes female athletes to lose period

temperature homeostasis

to maintain a constant core temp, heat lost must match heat gain

heat gain

\-PA

\-TEF: thermic effect of food

\-hormonal responses

\-warm environment

heat loss

\-radiation

\-conduction

\-convection

\-evaporation

conduction

transfer of heat via direct contact with another surface (cold bleacher)

convection

transfer of heat via movement of molecules within fluids or gases (air)

evaporation

\-transfer of heat when liquids change physical state becoming gas

\-80% heat loss during exercise

\-20% heat loss at rest

radiation

\-transfer of electromagnetic heat waves

\-60% heat loss at rest

\-5% heat loss during exercise

evaporative cooling rate depends on

\-temp & relative humidity

\-convective current around the body

\-amount of skin surface exposed

factors related to heat injury

\-aclimatization

\-hydration

\-wind

\-temp

\-humidity

\-clothing

\-fitness

\-exercise intensity

acclimatization

\-earlier onsent of sweating

\-↑ sweat rate, ↓ body temp

\-9-14 days, > 1 hr exercise

hydration

↑ sweat rate, ↓ body temp

wind

\-↑ heat loss by convection

\-↑ rate of evaporation

temp

\-↑ temp=heat gain

\-evaporative cooling

humidity

\-↑ humidity=heat gain

\-lose evaporative cooling

clothing

need skin exposure

fitness

↑ fitness=↓ risk of injury

exercise intensity

\-↑ intensity=↑ risk of injury

\-monitor intensity closely

sweat rate

2-3 L/hr

dehydration: CV function

\-↓ skin BF, SV, & Q

\-↑ HR & (a-v)O₂, maintain O₂ supply to muscle

hyperthermia: CNS

\-motivation & motor control

\-hypothalamus can be damaged

hyperthermia: neuromuscular

↓ neural activation of muscle (MU recruitment)

signs of heat acclimatization

\-↑ plasma volume & VR

\-early onset of sweating during exercise

\-more dilute sweat (less Na⁺ lost)

\-↑ SV & ↓ HR, Q is maintained

\-↑ capacity for sustained sweat response

\-↓ core temp for given workload

\-↓ glycogenolysis

dehydration

\-1%: rapid ↑ in temp

\-2%: ↓ performance

\-3%: ↓ coordination

\-4%: headache/nausea

\-5%: failure of thermoreg

\-6%: serious risk for collapse, permanent injury, & organ failure

dehydration calculation

\[(pre-exercise kg−post-exercise kg)÷pre-exercise kg\]×100

gastric emptying rates affected by

\-temp

\-pH (acidity)

\-volume of fluid

\-CHO (6%), ↓ fat, ↓ protein, ↓ fructose

max gastric emptying rate

1\.2 L/hr

water replacement before exercise

\-300-500 mL H₂O, 2 hrs prior (based on hydration status)

\-more H₂O w/ glycerol (“hyperhydration”)

\-1.2 g glycerol/kg w/ 26 mL water/kg for 2 hrs prior

water replacement during exercise

\-< 1 hr: H₂O only

\->1 hr: H₂O & CHO

\-> 2 hrs: add Na⁺ (40 mmol/L)

rehydration is improved by

\-volume ingested > 1.5 times body weight loss

\-CHO-electrolyte solution is ingested

\-glycerol is added to drink

severe hypohydration

\-> 4% body weight loss

\-can require >24 hrs for complete rehydration