1) The document lists 7 group members working on a project about neural mechanisms of respiration. 2) It then describes the respiratory centers located in the brain stem, including the medullary respiratory center and pontine respiratory center which help control breathing. 3) Within the medulla, the ventral and dorsal respiratory groups contain neurons that send signals to respiratory muscles.

1. Group Members:
1) HASIBUL HASAN HREDOY
2) DIVIYADEVI PARAMASIVAM
3) NUR SYAFIQAH BINTI FAIDZUL HASSAN
4) RAS DALILY BINTI RASMAN
5) ALISHA DZAZKIA JASMINE
6) FARAH FADHILAH HERMAWATI
7) LEENA ABDU ALI AL-HAZMI

6. #Neuralmechanisms
Brain Stem
Pons
Medulla
Oblongata

7. ֎ Respiratory center :
◊ located in the medulla oblongata and pons in the brainstem
◊ made up of three major respiratory groups of neurons :
 two in the medullary respiratory center and one in the pontine
respiratory center
֎ Medullary respiratory center :
◊ located in the medulla oblongata
◊ primary respiratory control center
◊ send signals to the muscles that control respiration
◊ also controls the reflexes for non respiratory air movements :
 coughing
 sneezing
 swallowing
 vomiting.
֎ There are two regions in the medulla that control respiration:
◊ The ventral respiratory group
◊ The dorsal respiratory group

8. The dorsal respiratory
group (DRG)
The ventral respiratory
group (VRG)
◊ DRG controls the basic rhythm
breathing by triggering
inspiratory impulses.
◊ Integrate input from peripheral
sensory , chemoreceptor and send
information to VRG
◊ Mainly composed of inspiratory
neurons
◊ These neurons send impulses to
the motor nerves of diaphragm
and intercostal muscles and
causes it to contract, resulting in
inspiration
◊ Contain both inspiratory and
expiratory neurons
◊ Inspiratory neuron
 VRG sends inspiratory
impulses that travels along
phrenic nerve and intercostal
nerve
 This will excite diaphragm
and external intercostal muscle
 Causes Thorax to expand and
air rushes into the lung
◊ Expiratory neuron
 VRG send expiratory signals
to abdominal muscles and internal
intercostal that results in
expiration.

9. ֎ Pontine respiratory center :
◊ pons modifies the output of medullary
centers
◊ consists of the apneustic and
pneumotaxic centers
◊ apneustic center stimulate neurons in
the DRG, controlling the depth of
inspiration, particularly for deep breathing.
◊ pneumotaxic center inhibits the activity
of neurons in the DRG, allowing relaxation
after inspiration, thus controlling the
overall rate.
◊ also receive input from higher brain
center and from various sensory receptors

12. * In plasma,CO2 combines with water to form
carbonic acid
CO2 + H2O H2CO3
* Since the process involves no enzyme this
process occurs very slowly in plasma.
H+
HCO3

13. * Most CO2 is transported in the form of
hydrogencarbonate or bicarbonate ions
* CO2 from the tissues dissolve into red blood cell
(rbc)
CO2 + H2O H2CO3
* It combines with water to form unstable carbonic
acids (H2CO3)
* Catalysed by carbonic anhydrase enzyme in rbc
* Carbonic acid dissociates into HCO3 & H+
(HCO3 )
Carbonic anhydrase

14. CO2 + H2O H2CO3
* As more CO2 is transported,HCO3 accumulate
* Since membrane of rbc is permeable to
negative ions, HCO3 diffuse out from rbc into
plasma
* When HCO3 diffuse out, it causes the rbc to be
positively charged & plasma becomes negatively
charged
* To maintain electroneutrality, chloride ions(CI )
diffuse into rbc
* This process is known as chloride shift
H+
HCO3

15. CO2 + H2O H2CO3
* Increasing of H+ reduce the pH of rbc
* Accelerate Hb(O2)4 to dissociate into Hb & O2
* O2 diffuse into the tissue
H+ + Hb HHb
* H+ combine with Hb to form hemoglobinic acid
(HHb)
* Hb act as buffer to avoid the pH from reducing
H+
HCO3

17. * CO2 from the tissue dissolve into rbc
* Combine with Hb to form carbaminoglobin
(HbCO2)
Hb + CO2 Hb(CO2)4
* or combine with HHb to form
carbaminohemoglobinic acid (HHbCO2)

18. Breathing rate
- Determined by how long inspiratory center is active
Breathing depth
- More stimulation, more motor units excited, greater force
of breath
Factors :
1) Chemical factor
2) Influence of PO2
3) Influence of PCO2
4) Arterial pH
5) Higher brain center
6) Other factors

19.  Sensory receptors that are sensitive to these factors are called chemoreceptors.
# chemoreceptors in the medulla oblongata called central chemoreceptors
* sensitive to increases in H+ and CO2 in the cerebrospinal fluid.
# chemoreceptors in the carotid bodies and aortic bodies are called peripheral
chemoreceptors
* sensitive to changes in CO2, H+, and O2,
* carotid bodies are located in the walls of external carotid arteries
* aortic bodies are located in the aortic arch

20. * Accumulation of CO2 is hydrated to carbonic acid
* the acid then dissociates to H+
* H+ concentration increases in cerebrospinal fluid
* the DRG relays the information so that the VRG is stimulated
to increase the rate and depth of breathing
* this increases the rate of CO2 and H+ removal
* returns their concentrations to normal resting levels..
* If the CO2 and H+ concentrations in the blood or
cerebrospinal fluid are abnormally low, breathing is slow and
shallow until their concentrations increase to normal levels.

21. *Peripheral chemoreceptors in the carotid and aortic
bodies are sensitive to changes in blood O2
*PO2 must drop to at least 60mmHg before O2 level
become major stimulus for increased ventilation
*Once it below 60mmHg, brain stem will suffer
from O2 starvation and their activity will depressed
*Peripheral chemoreceptor become excited and
stimulate respiratory centers to increase ventilation

22.  Changes in arterial pH can modify respiration
even though PCO2 and PO2 are normal.
 Mediated by the peripheral chemoreceptor as H+
cant get through the blood brain barrier
 Factor changes arterial pH
- CO2 retention
- Lactic acid during exercise
- Fatty acids metabolites (ketone bodies) in
diabetic patient
 When pH is low, respiratory is increased to
achieved ideal.

23.  Nerve impulses from higher brain centers
also alter the rhythmic cycle of breathing.
 Involuntary nerve impulses formed by higher
brain centers in the cerebral cortex and
the hypothalamus during emotional
experiences such as :
* anxiety
* fear
* excitement
● rise and drop of body temperature increase and
decrease respiration

24.  Exert conscious breathing control over the rate and depth
 Hold breath and extra deep breath
 Stretch respirator in the lung stimulated when lung is
inflated and send signal to end inspiration
 Accumulated mucus, inhaled debris or dust and noxious
fume stimulate receptor in the bronchioles that promote
reflex constriction of the air passage

29.  Exercise  High Altitude

30. o During exercise, human body needs greater amount
of oxygen to reach the demand of oxygen by muscle
tissues.
o Various short term changes must occur to reach the
demand of oxygen.
o Eventually, exercise can induce long term changes
which can be healthy or unhealthy.

31. Short term changes
o During exercise, carbon dioxide levels rise in arterial
blood. Carbon dioxide induces vasodilation in the
arteries while the heart rate increases, which leads
to better blood flow and better oxygen delivery to
the tissues.
o Additionally, the respiratory rate increases as a result
of higher carbon dioxide levels (through
chemoreceptor regulation
o If exercise is too intense for oxygen demands to be
satisfied in the short term, anaerobic respiration will
be used to make up for the ATP in the muscles.

32. Beneficial long term changes
o In the long run, exercise results in increased levels of
arterial oxygen levels at rest.
o Increased oxygen levels in the body are especially
important to the long-term health of the brain and
heart, two organs that are vital to sustain life and
that require large amounts of oxygen to function
well.
o Exercise also has beneficial effects for reducing
stress.

33. o An increase in altitude results in a decrease in
atmospheric pressure. As a result, it is more difficult
for a body to achieve the same level of oxygen
saturation at high altitude than at low altitude, due
to lower atmospheric pressure. In fact, hemoglobin
saturation is lower at high altitudes compared to
hemoglobin saturation at sea level.

34.  As you recall, partial pressure is extremely important
in determining how much gas can cross the
respiratory membrane and enter the blood. A lower
partial pressure of oxygen means that there is a
smaller difference in partial pressures between the
alveoli and the blood, so less oxygen crosses the
respiratory membrane
 The number of oxygen molecules that enter the
tissue from the blood is nearly equal between sea
level and high altitudes.

35. Acclimatization
Over a period of time, the body adjusts to
accommodate the lower partial pressure of oxygen. The
low partial pressure of oxygen at high altitudes results
in a lower oxygen saturation level of hemoglobin in the
blood. In turn, the tissue levels of oxygen are also
lower. As a result, the kidneys are stimulated to
produce the hormone erythropoietin (EPO), which
stimulates the production of erythrocytes, resulting in a
greater number of circulating erythrocytes in an
individual at a high altitude over a long period.

37.  Exercise is associated with both increased
rate and increased depth of breathing,
resulting in enhanced alveolar ventilation.
 The movement of muscles causes production
of Co2 and H+
 To maintain homeostasis, the amount of CO2
produce must equal to the amount of O2
taken to the body.
 Hence, we need to increase the ventilation
in the respiratory system.
 “ventilation” is how much air (in litres) is
breathed in & out in one minute.

38.  When exercise begins, mechanoreceptors
and proprioceptors in muscles and joints
send information about movement to the
motor cortex. Descending pathways from
the motor cortex to the respiratory control
center of the medulla oblongata then
immediately increase ventilation.

40.  As muscle contraction continues, sensory
information feeds back to the respiratory
control center to ensure that ventilation and
tissue oxygen use remain closely matched.

42. Homeostasis is maintained by the respiratory
system in two ways:
- regulation of blood pH.
- Gas exchange
The two chemicals in charge of these processes
are
- Oxygen
- Carbon dioxide

43.  Appears in the alveoli
 Oxygen diffuse outside across the cell membrane
of the cell that lining the alveolus
 Same thing applies for blood capillary, until it
reach
red blood cell and bind to hemoglobin
 Similarly, carbon dioxide can diffuse
across cell membranes

44. Features of gas exchange surface:
 Large surface area
 Very thin
 Moist lining
 Good supply of blood
 Good ventilation

46.  Blood pH
pH is the concentration of hydrogen ions
(H+).
The maintenance of blood pH within
normal limits called acid-base
homeostasis.
Normal blood pH:

47.  Acidosis: When blood pH is too low, the blood
becomes too acidic due to the presence of
too many H+ ions
 Alkalosis: When blood pH is too high, the
blood becomes too basic due to the lack of
H+ ions

48.  Normal metabolism produce CO2 in the blood
 CO2 combines with H2O to form carbonic acid
which dissociate into H+ ions and bicarbonate
 pH basically depends on the amount of H+ ions
 The regulation happens by controlling the
respiratory depth and rate

50. Air movement the occur in addition to
breathing are called non respiratory
movements. They are use to
- clear air passages like coughing and sneezing
- express emotions as in laughing and crying

51.  The function of a sneeze is to clear the upper
respiratory passages.
 Initiated by a mild irritation in the lining
of nasal cavity
 Mechanoreceptors will send signals
up to the sneezing center in the lateral medulla
 In response, it will lower palate muscle and raise
tongue muscle. Result in closing the mouth partially
 Air will forced to go out through the nose causing a
strong exhalation
 Resulting of wiping anything that irritates
mechanoreceptors
 Powerful exhale through the nose.

53.  The function of a cough is to clear the lower
respiratory passages.
 Irritation occurs in mechanoreceptors lining the
trachea
 Mechanoreceptors will send signals
up to the sneezing center in the lateral medulla
 In response, The vocal cords will close, and
abdominal and internal intercostal muscle
contract increasing the pressure behind the
epiglottis, in order to push the air out.
 The vocal cord is suddenly opened, and a blast
of air is forced upward from the lower
respiratory tract.

55. Higher oxygen demand will increase amount of
oxygen and carbon dioxide transport, your
respiratory rate will also increase. allowing
more oxygen to reach the lungs and blood to
be delivered to the muscle
At rest, your respiratory rate is about 14 per
minute but can increase to 32 per minute
during exercise.

57.  Leading cause of death
 Most of them are preventable
 Most fatal: Aspiration Peneumonia
 Most vulnerable age group 5 to 65 years

59.  Chronic obstructive pulmonary disease (COPD) is
a progressive life threatening lung disease that
causes breathlessness and predisposes to
exacerbations and serious illness.
 The Global Burden of Disease Study reports a
prevalence of 251 million cases of COPD globally
in 2016.
 Globally, it is estimated that 3.17 million deaths
were caused by the disease in 2015 (that is, 5%
of all deaths globally in that year).
 More than 90% of COPD deaths occur in low and
middle income countries.
 The primary cause of COPD is exposure to
tobacco smoke (either active smoking or second-
hand smoke).

60.  The primary cause of COPD is tobacco smoke
(including secondhand or passive exposure).
Other risk factors may include:
 indoor air pollution (such as solid fuel used
for cooking and heating)
 outdoor air pollution
 occupational dusts and chemicals (such as
vapours, irritants, and fumes)
 frequent lower respiratory infections during
childhood.

61.  Shortness of breath, especially during
physical activities
 Wheezing
 Chest tightness
 Having to clear your throat first thing in the
morning, due to excess mucus in your lungs
 A chronic cough that may produce mucus
(sputum) that may be clear, white, yellow or
greenish

62.  Not curable
 But it is possible to reduce symptoms

63.  Asthma is one of the major
noncommunicable diseases. It is a chronic
disease of the the air passages of the lungs
which inflames and narrows them.
 Some 235 million people currently suffer
from asthma. It is a common disease among
children.
 Most asthma-related deaths occur in low-
and lower-middle income countries.
 According to the latest WHO estimates,
released in December 2016, there were 383
000 deaths due to asthma in 2015

64.  Having a blood relative with asthma
 Having another allergic condition
 Being overweight
 Being a smoker
 Exposure to exhaust fumes or other types of
pollution

65.  Symptom:
• Shortness of breath
• Chest tightness or pain
• Trouble sleeping caused by shortness of breath, coughing or
wheezing
• A whistling or wheezing sound when exhaling (wheezing is a
common sign of asthma in children)
• Coughing or wheezing attacks that are worsened by a
respiratory virus, such as a cold or the flu
 Causes:
• Causes of this disease is not clear
• But there are some factors that trigger Asthma.

66.  Life long disease and not curable
 But medication can reduce the symptoms
 Stay away from risk factors

67. Causes:
 Virus
 Bacteria
 Fungal infection
Risk Factors:
 being very young or elderly,
 crowded living conditions,
 malnutrition,
 HIV infection
 lack of breast- feeding in infants,
 chronic health conditions and exposure to
tobacco smoke or indoor air pollutants

68.  Congestion or runny nose
 Dry cough
 Sore throat
 Low-grade fever
 Mild headache

69.  In some cases, no treatment needed
 over-the-counter medications for a cough or
fever
 plenty of rest
 drinking plenty of fluid
In some case, doctor might prescribe:
 Antibiotics

70.  Latent TB. In this condition, you have a TB
infection, but the bacteria remain in your body
in an inactive state and cause no symptoms.
Latent TB, also called inactive TB or TB
infection, isn't contagious. It can turn into active
TB, so treatment is important for the person
with latent TB and to help control the spread of
TB. An estimated 2 billion people have latent TB.
 Active TB. This condition makes you sick and in
most cases can spread to others. It can occur in
the first few weeks after infection with the TB
bacteria, or it might occur years later.

71. Causes:
TB is caused by bacteria that spread from person to person through
microscopic droplets released into the air. This can happen when
someone with the untreated, active form of tuberculosis coughs,
speaks, sneezes, spits, laughs or sings.
Symptoms:
 Coughing that lasts three or more weeks
 Coughing up blood
 Chest pain, or pain with breathing or coughing
 Unintentional weight loss
 Fatigue
 Fever
 Night sweats
 Chills
 Loss of appetite

72.  Vaccination to prevent
 Antibiotics

73.  Lung cancer is also the most fatal cancer
globally. In 2012, 1.6 million people died
from lung cancer, accounting for 19.4% of the
total deaths attributable to cancer.

75.  A cough that does not go away or gets worse
 Coughing up blood
 Chest pain that is often worse with deep
breathing or laughing
 Hoarseness
 Weight loss and loss of appetite
 Shortness of breath
 Feeling tired or weak
 Infections such as bronchitis and pneumonia
that don’t go away or keep coming back

76.  Surgery
 Lobectomy
 Radiofrequency ablation (RFA) and
microwave ablation (MWA)
 Radiotherapy
 Chemotherapy