Exam 3 Flashcards
What affects % saturation of Hb
Composition of inspired air
Alveolar vent. rate
efficiency of gas exchange
What affects amount of Hb binding sites
Hb content per RBC and number of RBCs
Oxyhemoglobin Saturation curves
Show the physical relationship between PO2 and Hb saturation
Shift right/left on a Oxyhemoglobin curve
Right: Decreased affinity for O2 –> release more O2 to tissues, more significant
Left: Increased affinity for O2 –> more O2 stays bound to Hb
Normal numbers for Hb saturation at 100 and 40 mmHg PO2
@ 100 (arteries): 98%
@ 40 (resting cell/venous): 75%
Why is only ~25% of available O2 used at rest
Allows for a reservoir of O2 to accumulate on Hb incase metabolism increases or demand increases in another way.
Hb saturation of skeletal muscle
PO2 = 20 mm Hg
Hb 30%
–> Body using 70% of O2
Fetal Hb Oxyhemoglobin curve
left shift –> increased affinity
Need to get O2 from mom’s blood
Factors that cause a Change in Hb shape
Plasma pH, temp, PCO2, 2,3-BPG
Effect of plasma pH on Oxyhemoglobin
Drop in pH (more acidic) –> right shift, more O2 released
Effect of temp on Oxyhemoglobin
Increase temp –> right shift
Effect of 2,3-BGP on Oxyhemoglobin
Increase in the intermediate means increase in glycolysis which is increase of metabolism which causes a right shift and greater O2 release.
effect of high CO2
Lowers plasma pH (acidic)
CNS depressant (inhibits/slows neural function)
Ways Co2 is transported in blood
7% dissolved in plasma
23% Bound to Hb
70% Dissolved as bicarbonate ions which act as mode of transport, buffer in plasma, and relies on carbonic anhydrase
Go over transport pathway on slide 28
Regulation of ventilation
depends on skeletal muscle and somatic motor neurons
3 factors that influence rate of vent
CO2 receptors in medulla Oblongata (central chemo)
O2/pH receptors in carotid/aortic bodies (peripheral chemo)
Emotional and voluntary control
*Control still not totally understood
Neural control of breathing
- Resp. neurons in medulla control inspiratory and expiratory muscles
- Neurons in Pons integrate sensory info and interact with medullary neurons to influence ventilation
- The rhythmic pattern of breathing arises from a brainstem neural network with spontaneously discharging neurons
- Ventilation is subject to continuous modulation by chemo/mechano receptor linked reflexes and higher brain centers (emotional)
Dorsal Respiratory group (DRG)
Medulla Oblongata
Receives sensory input from CN IX and X and Chemoreceptors monitoring CO2
Controls muscles of inspiration
Ventral Respiratory Group (VRG)
Medulla Oblongata
Pre-botzinger complex
Controls active expiration and greater than normal inspiration
Controls muscles of larynx, pharynx, and tongue (vocalization)
Pre-Botzinger Complex
Spontaneously firing neurons
Pacemaker of breathing
Pontine Respiratory group (PRG)
Pons
Receives sensory input from DRG
Influence initiation and termination of breathing rate
Provides tonic input to medullary groups
Central Chemoreceptors
Primary stim for changes in vent. rate
CO2 receptors in ventral medulla
Detect CO2 in CSF
See diagram slide 37
Functions of the kidney
- Regulation of Extracellular fluid volume and blood pressure
- Regulation of osmolarity
- Maintenance of ion balance
- Homeostatic regulation of pH
- Excretion of wastes
- Production of hormones
Regulation of Extracellular fluid volume and blood pressure
Work with CVS to maintain ECF volume