Chapter 17: The Respiratory System

Question 1

three phases of respiration

Answer 1

ventilation: the exchange of air between the atmosphere and the alveoli.
gas exchange between air and the blood of lungs and the blood of lungs and tissue of the body.
oxygen utilization: done by the tissues of the body by energy liberating reactions.

Question 2

parts of the respiratory system?

Answer 2

nose, pharynx, larynx, trachea, bronchi, bronchioles, pulmonary alveoli.

Question 3

upper respiratory path?

Answer 3

nose and the pharynx along with associated parts

Question 4

lower respiratory path?

Answer 4

larynx, trachea, bronchi, bronchioles, pulmonary alveoli.

Question 5

nose

Answer 5

the nose opens into the nasal cavity. it is divided into two halves with the help of the cartilaginous internasal septum. the two halves are called nasal fossa. the nose anteriorly opens into the nostrils made up of stratified squamous epithelial and posteriorly into the nasopharynx made up of pseudostratified ciliated columnar epithelial with goblet cells secreting mucus.

it warms, moistens and cleans the air inspired. the dust and pollen is stuck in the hair and the mucus.

the olfactory epithelium and receptors for smell.

Question 6

larynx

Answer 6

it is known as the voice box the connects the pharynx with the trachea.

it prevents food and fluid from going inside the trachea and is also responsible for the production of voice

Question 7

trachea

Answer 7

is a long tube that connects to the bronchi. it is made of hyaline cartilage to ensure it remains open throughout the mucosa is pseudostratified ciliated epithelium cells and mucus-secreting goblet cells to protect from dust

Question 8

pulmonary alveoli

Answer 8

the alveolar duct, pulmonary alveoli and the alveolar sac are the main respiratory unit of the lung. they are many in size to increase the surface area of exchange. the rate of diffusion is increased cause the alveoli are surrounded by a single layer of cells. they are made up of two types of cells:

pneumocytes 1: permits diffusion
pneumocytes 2: produces surfactant to per cent alveoli from collapsing, moistens the alveoli from efficient diffusion and repairs the type 1 cells.

Question 9

breathing

Answer 9

breathing is divided into two phases inspiration and expiration which is alternated by increasing and decreasing the volume of the thoracic cavity.

Question 10

inspiration

Answer 10

1. the diaphragm contracts and flattens increasing the ventral size of the thoracic cavity
2. the external intercostal muscles contract while the intercostal muscles relax increasing the diameter of the cavity.
3. this combined action leads to the increase in volume and decrease in pressure in the lungs as compared to the atmosphere
4. air rushes in

Question 11

expiration

Answer 11

1. the diaphragm relaxes into dome-shape
2. the external muscles relax and the internal muscles contract to bring the rib cage into its original position.
3. combined action causes the volume to increase and pressure to decrease.
4. air rushes out.

Question 12

spirometer?

Answer 12

it is a device to measure the respiratory volume

Question 13

neural regulation of respiration?

Answer 13

respiration is controlled by three centres of the brain- the respiratory centre, the apneustic centre and the pneumotaxic centre.

the respiratory centre is located in the medulla oblongata and has aggregate nerve cells responsible for inspiration and expiration. they work reciprocally, if one is stimulated the other is inhibited.

the apneustic centre and pneumotaxic centre are located in the pons and aid the respiratory centre. apneustic centre aids inspiration while pneumotaxic inhibits inspiration

Question 14

chemical regulation of breathing?

Answer 14

the respiratory centre in the medulla oblongata responds to stimuli by chemoreceptors to control ventilation.

the central chemoreceptors detect changes in the carbon dioxide levels
the peripheral chemoreceptors of the aortic and carotid bodies detect carbon dioxide, oxygen and ph levels.

when there is increased physical activity, metabolism increases and so does levels of CO2.
the chemoreceptors relay the response to the respiratory centre which signals the diaphragm and intercostal muscles for increased rate of ventilation.

increase physical activity can increase vital capacity.

Question 15

exchange of gases

Answer 15

the exchange of gases takes place through diffusion along the concentration gradient.

the venous blood from the tissue has high PCO and low PO and the alveoli have high PO and low PCO. as a result exchange takes place.

the blood capillaries have high PO and low PCO. the tissue has high PCO and low PO as a result the exchange takes place.

Question 16

increase the efficiency of diffusion?

Answer 16

diffusion path should be short.

the concentration gradient should be high.

Question 17

transport of oxygen

Answer 17

1. very little oxygen gets dissolved in the plasma
2. most of the oxygen is transported as oxyhaemoglobin
3. absorbed by RCB

Question 18

haemoglobin

Answer 18

haemoglobin is a conjugated protein with four subunits each having a prosthetic group (haem - Iron) attached to it. an apoprotein part called globin.

as it binds with more O2 its affinity for O2 increases. this is known as cooperative binding.

Question 19

oxyhaemoglobin dissociation curve

Answer 19

this curve shows the relationship between the percentage saturation of oxyhaemoglobin and the partial pressure of oxygen. the reason why the graph is not linear in that the binding potential changes with saturation.

right shift - reduced affinity
increase in temperature
increase in H+
increase in 2,3-DPG

left shift - increased affinity
decrease in temperature
decrease in H+
decrease in 2,3-DPG

Question 20

transport of carbon dioxide

Answer 20

1. some of the carbon dioxides travels in the plasma in the physical state.
2. some of the carbon dioxides combine with the haemoglobin to form carboxyhaemoglobin.
3. travels in the form of bicarbonate:
   the carbon dioxide enters the RCB and then combines with water to form carbonic acid which dissociates and then chloride shifts and then becomes sodium bicarbonate.

Question 21

asthma

Answer 21

it is when the respiratory pathways narrow down and get inflamed producing excess mucus which can make it difficult to breath

symptoms: chest pain, wheezing, coughing,
cause: pollen, allergen, pollution
solution: anti-inflammatory drugs, bronchodilator drugs

Question 22

emphysema

Answer 22

the alveoli in the lungs collapse decreasing surface area.

symptoms: shortness of breath
cause: smoking cigarettes, pollution

Question 23

occupational respiratory disorders

Answer 23

disorders caused by inhaling chemicals at a certain occupational site.

eg: pneumoconiosis, asbestosis
symptoms: chest pain, shortness of breath, wheezing

Question 24

tidal volume

Answer 24

the volume of air that is taken up during normal respiration (500 ml)

Question 25

inspiratory reserve volume

Answer 25

the volume of air taken up during forced inspiration

2500-3000 ml

Question 26

expiratory reserve volume

Answer 26

the amount of air that is expelled during forced expiration (1000-1100 ml)

Question 27

reserve volume

Answer 27

the volume of air in the lungs after forced expiration. (1100-1200 ml)

Question 28

inspiratory capacity

Answer 28

the volume of air inspired after normal inspiration (3500 ml)

Question 29

expiratory capacity

Answer 29

the volume of air expired after normal inspiration (1600 ml)

Question 30

functional residual capacity

Answer 30

the volume of air left in the lung after normal expiration. (2300 ml)

Question 31

vital capacity

Answer 31

the volume of air a person can inspire after forced expiration (4600 ml)

Question 32

total lung capacity

Answer 32

the total volume of air contained in the lungs at maximum forced inspiration (6000 ml)

Question 33

dead space

Answer 33

the air in the respiratory path that cannot reach the alveoli and cannot be used in the gaseous exchange. 150 ml