Final: Respiration 6 Flashcards
how do RBCs modify their micro-environment to make O2 uptake/delivery more efficient (3)
- regulation of organic phosphates
- regulation of pH values
- goal is to optimize blood P50
O2, CO2, and Hb transport interaction (3)
- strong interactions within RBC due to Bohr and Haldane effects
- O2 uptake facilitates CO2 removal at gas exchanger
- CO2 removal from tissues enhances O2 unloading from blood
how does increased PCO2 affect the body (3)
- increases [HCO3-]
- decreases pH (increase in [H+])
- reaction shifts to produce bicarbonate
how does decreased PCO2 affect the body (3)
- decreased [HCO3-]
- increased pH (decrease in [H+])
- reaction shifts to produce CO2
how does hyperventilation affect PCO2
- decreases PCO2
how does hypoventilation affect PCO2
- increases PCO2
what is the predominant regulator of acid-base balance in air breathers (2)
- respiration for modulation blood CO2 levels
- kidneys/gills for regulation HCO3- levels
respiratory alkalosis (2)
- caused by hyperventilation and blowing off of CO2
- increases pH
respiratory acidosis (2)
- caused by hypoventilation, which permits CO2 to accumulate
- decreases pH
metabolic acidosis (2)
- acidosis during anaerobic respiration
- due to elevated lactate levels
regulation of respiratory systems
- regulation
- responds to…
- requirements (2)
- respiratory systems are tightly regulated
- respond to changes in external and internal environments
- must be able to supply sufficient O2 to meet metabolic demands
- must be able to remove CO2 to prevent pH disturbance
how do vertebrates regulate respiratory systems (3)
- regulating ventilation (frequency & depth)
- regulating oxygen carrying capacity and affinity
- regulating tissue perfusion
what kind of process is ventilation (2)
- an automatic process
- continues when we are unconscious
what regulates ventilation and where is it located (2)
- central pattern generator (groups of neurons) in medulla
- Pre-Botzinger complex
Pre-Botzinger complex
- important respiratory rhythm generator in mammals
how are rhythm generators further modulated (5)
- other receptors and emotional stimuli act through hypothalamus
- peripheral and central chemoreceptors
- receptors in muscles and joints
- stretching receptors in lungs
- irritant receptors in lungs/trachea
basic ventilation function (3)
- rhythmic firing of central pattern generators initiate ventilatory movements via interneurons
- send nerve signal to somatic motor neurons
- activates skeletal muscles for breathing (intercostal and diaphragm muscles)
ventilation modulation via feedback (3)
- chemosensory input modulates output of central pattern generators
- most animals have central and peripheral sensors
- chemoreceptors detect changes in CO2, H+ and O2
central sensor location
- brain
peripheral sensor location
- outside of the brain
what determines what chemoreceptors mainly sense for
- depends in the medium that the animal respires
water breathers: primary sensing mode
- O2
air breathers: sensing mode (2)
- primary: CO2
- secondary: O2
air breathers: central sensors
- detect pH (related to CO2) of cerebrospinal fluid, fluid surrounding brain and spinal cord
air breathers: peripheral sensors (2)
- have 2 peripheral sensors that primarily sense low PO2
- aortic body and carotid body
air breathers: aortic body sensor
- blood going to body
air breathers: carotid body sensor
- blood going to brain
water breathers: sensors (2)
- internal PO2 sensors within gills, gill cavity, and on gill surface
- PCO2/pH sensors in gills for environmental levels
other ventilation control mechanisms (3)
- mechanoreceptors
- secondary chemoreceptors
- conscious control
ventilation control mechanism: mechanoreceptors location (2)
- lungs
- bronchi
ventilation control mechanism: secondary chemoreceptors exmaples
- eg. CO2 sensors in lungs or pulmonary circulation
ventilation control mechanism: conscious control location (2)
- hypothalamus
- cerebrum
hyperoxia (2)
- higher than normal PO2 in environment, blood, or organ system
- rare terrestrial environmental condition, mostly aquatic
hypoxia
- lower than normal PO2 in environment, blood, or organ system
hypoxemia
- lower than normal arterial blood O2 content
hypoxia causes (3)
- environmental hypoxia (high altitude, burrows, etc)
- inadequate ventilation (hypoventilation)
- reduced blood Hb content (anemia)
hypercapnia
- higher than normal PCO2 in environment or blood
hypocapnia
- lower than normal PCO2 in environment or blood
high altitude conditions (3)
- barometric pressure drops, so PO2 drops as well
- low temperature
- low relative humidity
mount everest elevation
- highest altitude where people can survive a few hours breathing air
how can the blood adjust to high altitude (2)
- increase hematocrit/RBCs
- polycythemia
what are the negative implications of increasing hematocrit in high altitude (3)
- increases pulmonary arterial pressure due to high viscosity of blood
- causes right ventricular hypertrophy (thicker muscle) and congestive heart failure over time
- causes chronic mountain sickness
acute mountain sickness (3)
- 4-8 hours after ascent to 3300m or higher
- results in nausea, headache, insomnia, and possibly death
- 3 phases: acute response, acclimatization, and long term acclimatization
acute mountain sickness: acute response (3)
- increased ventilation
- decreased PCO2
- increased pH
acute mountain sickness: acclimatization (3)
- decreased ventilation
- PCO2 and pH recover
- hypoxemic
acute mountain sickness: long term acclimatization
- pH in cerebral spinal fluid slowly adjusted so ventilation can be elevated without disturbing CSF pH
how can mountain sickness be alleviated (a drug)
- a carbonic anhydrase inhibitor
how can a carbonic anhydrase inhibitor (acetazolamide) alleviate mountain sickness (3)
- bicarbonate cannot be converted to CO2 as easily
- ensures that CSF pH does not raise too high so that ventilation can stay elevated to avoid hypoxia
- excess bicarbonate will be released in urine through kidneys
how can organic phosphate levels change in high altitude
- increase concentration to increase tissue O2 delivery
is a higher or lower P50 more beneficial during exposure to environmental hypoxia? (3)
- lower P50 is more beneficial in OEC
- higher affinity for O2, aiding in O2 loading at the lungs
- P50 cannot be too left shifted or O2 will not deliver to tissues
adaptations to altitude: examples (2)
- high altitude llama has lower P50 than the P50 range of lowland animals
- deer mouse native to high altitudes have lower P50 levels than low altitude deer mice due to changes in organic phosphate levels
what adaptation must high altitude animals have to accommodate for their low P50 (2)
- must have tissue-level mechanisms to aid in O2 delivery
- eg. increased capillary density or myoglobin
P50 difference in Andean Goose and Greylag loose (2)
- P50 of Andean Goose (can fly over Everest) is much lower than P50 of Greylag goose (cannot fly over Everest)
- difference from single aa substitution on Hb function
how can human P50 be genetically lowered
- site directed mutagenesis altering 1 aa in human Hb converts Hb functionally to that of the Andean goose
at what levels can enhancement to O2 flux occur at on the O2 transport cascade
- can occur at every level: ventilation, pulmonary diffusion, circulatory diffusion, muscle diffusion, muscle utilization, muscle ATP turnover
O2 transport cascade: important avian characteristics in ventilation
- tolerance of the hypocapnia caused by respiratory CO2 loss
O2 transport cascade: unique features of high fliers in ventilation (2)
- enhanced hypoxic ventilatory response
- more effective breathing pattern
O2 transport cascade: important avian characteristics in pulmonary O2 diffusion (2)
- crosscurrent gas exchange
- extremely thin and mechanically strong gas exchange barrier
O2 transport cascade: unique features of high fliers in pulmonary O2 diffusion
- larger lungs increase surface area for diffusion
O2 transport cascade: important avian characteristics in circulatory O2 diffusion (2)
- relatively large hearts
- cerebral perfusion is insensitive to hypocapnia
O2 transport cascade: unique features of high fliers in circulatory O2 diffusion (2)
- hemoglobin with higher O2 affinity
- multiple cardiac specializations
O2 transport cascade: important avian characteristics in muscle O2 diffusion (2)
- high capillary density/SA
- small muscle fibers
O2 transport cascade: unique features of high fliers in muscle O2 diffusion (2)
- even higher capillary density/SA
- mitochondria are redistributed closer to capillaries, reducing diffusion difference
O2 transport cascade: important avian characteristics in muscle O2 utilization (2)
- high aerobic capacity
- high capacity for fat oxidization
O2 transport cascade: unique features of high fliers in muscle O2 utilization
- sometimes greater aerobic capacity in flight muscles
O2 transport cascade: important avian characteristics in muscle ATP turnover
- fast-contracting aerobic fibers in flight muscle
O2 transport cascade: unique features of high fliers in muscle ATP turnover
- greater respiratory control by mitochondrial creatine kinase
adaptations to aquatic hypoxia (2)
- left shift of OEC due to reduction in ATP/GTP:Hb ratio
- hypoxia tolerant fish generally have low P50s
how might gills change in response to hypoxia (2)
- increased SA
- decreased thickness
adaptations to aquatic hypoxia: carp (2)
- experiences large increase in gill surface area during hypoxia
- cells packed between lamellae disappear in hypoxic and reappear again when conditions stabilize
if lamellae surface area increases by 2x ad thickness decreases by 2x, how would O2 uptake be affected
- 4x more O2 uptake
how do Lake Qinghai scale-less carp adapt to hypoxia (2)
- increase in total SA of gills during exposure to hypoxia
- reduction in blood water diffusion distance
