BIOL126 Lecture Notes - Lecture 10: Ventral Respiratory Group, Dorsal Respiratory Group, Bicarbonate Buffer System
10 Jun 2018
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Respiratory gases and acid base balance
-Acidosis is more common- due to acid production from normal metabolism
-CNS deterioration- comatose
-cardiac contractions weak, irregular, heart failure
-peripheral vasodilation, drop in BP, circulatory collapse
Types of acids in the body:
-fixed acids- stay on body- small adjustments made by kidney
-organic acids- can form ATP (reactant)- usually don't accumulate
-volatile acids- come out of section
-Vaporise- leaves body as a gas
Circulations of buffers:
-provide only temporary secretion to acid base imbalance
-Don’t eliminate H+ ions
-supply of buffer molecules is limited
3 major buffers:
-Protein buffer system- uses plasma proteins on blood
-Phosphate buffer system- buggers pH of ICF and urine
-Carbonic acid- bicarbonate buffer system- most important in ECF
Causes of acid-base balance disturbances:
-disorders
-Cardiovascular conditions
-Conditions affecting the CNS
Hydrogen ions:
-Are gained at digestive tract, through cellular metabolic activities
-are eliminated/balanced by kidney in urine, by lungs
Integrated Respiratory responses
Respiratory control centres:
-Located in the brainstem
-Medulla- inhalation/exhalation- poms oversees this to make sure it is a smooth process
-Poms- ensures a smooth transition in breathing and adjust depth and rate of breathing
-Changes in partial pressure of gas- anything with a low CO2 and a high CO2, the tissue of the
site will also try to deal with it as well as voluntary, involuntary control
-dorsal respiratory group (DRG)
-working all side tissue, both tidal and forced breathing
-ventral respiratory group (VRG)
-only active in forced breathing, both inspiratory, expiratory centres function
-(INTERACTION BETWEEN THESE SET THE PACE FOR RESPIRATION)
Apenustic and pneumotactic centres of pons:
-Apnecotic- constantly stimulating DRG
-Pneumotactic- modify pace of DRG
Two types of chemoreceptors:
-central chemoreceptors- sensitive to H+ changes in CSF
-peripheral chemoreceptors- sensitive to changes in pCO2, H+ and Po2 in blood
-Baroreceptors- stretch receptors in lining of blood vessels
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Blood
-Plasma proteins give the pressure placed on the fluid
-Plasma proteins mostly synthesised by liver (99%)
Characteristics of blood:
-temp slightly high than body temp
-Slightly alkaline
-5x viscous as water- create friction on endothelium
-size of liner determine how much blood flows through
Functions of blood:
1. transporting dissolved gases, nutrients, hormones, proteins, metabolic wastes
2. regulating hP, ion composition of ISF
3. restricting fluid loss at injury site
4. Defending against pathogens
5. Stabilising body temp
Erythrocytes (RBCs):
-1/3 of all body cells
-Hermatserit- percentage of forced elements in blood
-Haemoterit increased during dehydration after EPO secretion
Structure of erythrocytes:
-Biconcave dise, thin central region
-Shape important
-gives large SA: U- greater ratio faster exchange between RBCs, plasma
-can form stacks to smooth the flow through capillaries
-Flexibility so can enter small capillaries
Plasma:
-90% water
-Albiums- main contributor to blood colloid osmotic pressure
-Globlins- include antibodies, proteins for transport
-Fibrinogen functions in duffing
Haemoglobin (Hb):
-95% intracellular proteins
-major function carry O2, secondary function carry CO2
Erythropoiesis:
-Generation of new erythrocytes in red bone marrow regulated by erythropoietin (EPO), thyroid
hormone, audrogens, GH
-to produce RBCs- bone marrow needs amino acids
-EPO produced by kidney, liver
White blood cells:
-Contain nuclei, other organelles, lack haemoglobin, defend body against pathogens, removes
toxins, waste damaged cells
-Two groups based on appearance- greater leukocytes, agranular leukocytes
White blood cell functions:
-Neutroplis- first to arrive, engulf bacteria, attracts other WBC
-Eosinoplls- primary defence against multicellular pathogens
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Acidosis is more common- due to acid production from normal metabolism. Peripheral vasodilation, drop in bp, circulatory collapse. Xed acids- stay on body- small adjustments made by kidney. Organic acids- can form atp (reactant)- usually don"t accumulate. Provide only temporary secretion to acid base imbalance. Protein buffer system- uses plasma proteins on blood. Phosphate buffer system- buggers ph of icf and urine. Carbonic acid- bicarbonate buffer system- most important in ecf. Are gained at digestive tract, through cellular metabolic activities. Are eliminated/balanced by kidney in urine, by lungs. Medulla- inhalation/exhalation- poms oversees this to make sure it is a smooth process. Poms- ensures a smooth transition in breathing and adjust depth and rate of breathing. Changes in partial pressure of gas- anything with a low co2 and a high co2, the tissue of the site will also try to deal with it as well as voluntary, involuntary control. Working all side tissue, both tidal and forced breathing.
