respiratory Hap2

Question 1

8% of carbon dioxide is carried in the blood by

Answer 1

__dissolving in the plasma

Question 2

20% of carbon dioxide is carried in the blood attached to __

Answer 2

globin of haemoglobin ___

Question 3

70% of carbon dioxide is carried in the blood as __

Answer 3

_ bicarbonate ions ____

Question 4

respiratory homeostasis- type 1 chemorecepors

Answer 4

. Central chemoreceptors are located in the medulla
Detect changes in CSF which contains almost no protein buffers so these receptors
are very sensitive.
These chemoreceptors bind to H+ so they are sensitive to pH & PCO2
*They are sensitive to PCO2 because CO2 forms carbonic acid which liberates H+
*CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
*The reaction requires the enzyme carbonic anhydrase.
*H+ is measured using a pH scale. A decrease in pH means more H+ and more
acidity

Question 5

respiratory homeostasis- type 2 chemorecepor-periphreal

Answer 5

2. Peripheral chemoreceptors are located in the aortic arch and carotid bodies.
   These chemoreceptors are sensitive to pH, PCO2 and PO2
   These chemoreceptors detect changes in arterial blood

Question 6

what chemoreceptors do

Answer 6

(Both types of) Chemoreceptors stimulate respiratory centres in the DRG.
Activation of the Dorsal Respiratory Group is relayed to the VRG
The DRG and the VRG are located in the medulla oblongata
The frequency of efferent impulses to respiratory muscles increase
Diaphragm and external intercostals.
Breathing rate & volume increase

Question 7

Acid base levels in the blood are regulated by 3 methods.

Answer 7

1. Buffers ____ 2. Respiratory ____ 3. Renal _____

Question 8

what is most important efc buffer

Answer 8

Bicarbonate is the important ECF buffer

Question 9

where are phosphate buffers

Answer 9

Phosphate buffers are inside cells

Question 10

example of protein buffer

Answer 10

Haemoglobin is an example of a protein buffer

Question 11

what is extra bicarbonate used for

Answer 11

Extra bicarbonate is used buffering for

blood.

Question 12

what does excess co2 do

Answer 12

Excess CO2 will be combines with H2O to form

carbonic acid inside red blood cells

Question 13

H+ role in buffer

Answer 13

Buffers work by combining with excess H+ or

releasing more H+

Question 14

what do tubular cell do with co2

Answer 14

Tubular cells in the kidneys convert CO2 into

H+ for excretion into urine

Question 15

Na exchange

Answer 15

Tubular cells in the kidneys actively transport

H+ into urine in exchange to Na+

Question 16

what is main organ for acd-base control

Answer 16

Kidneys are the main organ for maintaining

acid base balance

Question 17

Residual volume

Answer 17

Air remaining in lung after expiration

About 1200 ml

Question 18

Dead space volume

Answer 18

Air that remains in conducting zone and never reaches alveoli is about 150 mL
Dead space volume is part of the residual volume.

Question 19

what is the exchange of respiratory gases dependant on

Answer 19

The exchange of respiratory gases in both alveolar gas exchange and systemic gas exchange are dependent upon partial pressure gradients (oxygen and carbon dioxide)

Question 20

external respiration

Answer 20

During external respiration O2 diffuses from the alveoli into the blood of the pulmonary capillaries.
CO2 simultaneously diffuses in the opposite direction.

Question 21

diffusion at respiratory membrane

Answer 21

Partial pressure gradients of O2 and CO2 drive the diffusion of these gases across the respiratory membrane.

Question 22

alveoli

Answer 22

Alveoli are made of simple squamous epithelium on basement membrane

Question 23

haemaglobin and O2

Answer 23

Each Hb molecule can bind four O2 molecules and is called oxyhemoglobin (HbO2), and is 98 -100% fully saturated.

Question 24

venous o2 saturation

Answer 24

Normal venous O2 saturation is = 75%

Question 25

O2 unloading

Answer 25

At the alveoli: One O2 binds causing Hb to change shape so that
the next O2 can bind more easily, with the 4th binding most easy.
At the tissue level: One O2 unloads causing Hb to change shape
The next O2 can unload more easily, with the 4th unloading most easy.

Question 26

3 things that effect o2 sats

Answer 26

• high temp
• low pH
• high co2

Question 27

co2 unloading

Answer 27

At the alveoli: CO2 rapidly dissociate from Hb in the lungs where alveolar PCO2 is lower than that in blood
At the tissue: CO2 binds to globin where PCO2 is higher than that in blood

Question 28

Haldane effect

Answer 28

Haldane effect: The less O2 on the heme, the more readily CO2 binds on globin and the more Hb can buffer H+

Question 29

vrg

Answer 29

Ventral respiratory group (VRG): is involuntary rhythm generating and integrative centre.
It contains neurons that fire during inspiration (lasts for 2 seconds) and those that fire during expiration to stop inspiratory neurons (lasts for 3 seconds).

Question 30

drg

Answer 30

Dorsal respiratory group (DRG): DRG feeds information from stretch receptors and chemoreceptors (chemical factors) to VRG

Question 31

The H+ concentration in blood is regulated by:

Answer 31

Chemical buffer system
Brain stem respiratory centres
Renal mechanisms

Question 32

Chemical buffer system is:

Answer 32

a system of one or more compounds that resist pH changes when a strong acid or base is added
and therefore, provides protection against drastic changes in pH
react very quickly
all three buffer systems are limited in their capacity

Question 33

The three major buffer systems in the body are the:

Answer 33

Bicarbonate-in the extracellular fluid (blood)
Phosphate (ICF buffer)
Protein buffer system (ICF buffer)