Physiology exam 4 respiratory

g blood then heads to the right side of the heart

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: the lungs where the cycle will repeat as gas exchange takes place with the alveolar air. VII. RESPIRATORY ACID-BASE BALANCE Relationship between CO2 and pH: H2 O + CO2 ¯ H2 CO3 ¯ H+ + HCO3 G HCO3- binds to plasma proteins, so CO2 acts as an acid in the blood bicarbonate can't stay there and act as a buffer When H2O and CO2 mix, they form carbonic acid which dissociates into hydrogen ions and bicarbonate. pCO2 is the strongest stimulus affecting breathing rate i Respiration is normally adjusted to keep pace with the metabolic rate . more oxygen used and more CO2 made. CO2 levels really affect rate. Acid-Base imbalances: A. Respiratory acidosis pH in blood going down. caused by not enough CO2 leaving, breathing too slow will do this (hypoventilation, could be caused by diseases, concussion) B. Respiratory alkalosis pH in blood becomes more basic, rises. Hyperventilation relate to renal pH balance? kidneys have a more long-term adjustment. Kidney's job is more chronic, change secretion and absorption of H+ and bicarbonate. Respiration is more minute changes such as breathing differently during exercise, too quick for kidney to deal with VIII. REGULATION OF RESPIRATION BY CHEMORECEPTORS pH Two sets of chemoreceptors detect changes in ____________ & _____________ in the blood. pCO2 A. Central receptors: located in the medulla oblongata monitor the pH of CSF, very similar to pH in blood stream, essentially equal. B. Peripheral receptors in the aortic arch and carotid bodies. measure pH and PO2 levels in the blood send feedback to the medulla oblongata (somewhat secondary to central for rate moderation) Question: Why isn’t PO 2 an important contributor to control of respiration? oxygen is variable in our body, 160mmHg at sea level but decreases wherever we go. Don't want pO2 to affect your respiration rate. small changes in CO2 will change pH and this is why we monitor them as blood pO2 drops only increases the chemoreceptors sensitivity to PCO2 arterial pO2 has to fall by 50% before this effect occurs IX. REGULATION OF BREATHING There are 3 locations that help control breathing: 1. Medulla oblongata: site of the rhythmicity center (much like SA node) normally breath 12 times a minute semi-voluntary control of breathing A. inspiratory neurons (excitatory neurons) contract B. Expiratory neurons: inhibit inspiratory neurons. relaxes diaphragm, exhale. 2. Pons: a. pneumotaxic center regulate breathing (12 times a minute) simply frequency b. apneustic center increase depth of breathing, example keep inspiratory neurons on a little bit longer pressure will drop a little bit, and we will breath in a little bit more. delays onset of inspiratory cortical control 3. Cerebral cortex: breathing is "semi-voluntary" frontal lobe can send voluntary commands to respiratory muscles. overrides the rhythmicity center X. LUNG VOLUMES AND CAPACITIES Spirometry is used to measure lung volumes and capacities and is useful in diagnosing pulmonary diseases. Th...
View Full Document

This note was uploaded on 09/30/2013 for the course P 215 taught by Professor Mynark during the Fall '12 term at Indiana.

Ask a homework question - tutors are online