B9. 3 Respiratory System

Question 1

Describe the passage of air down the respiratory system

Answer 1

Nasal passage
Pharynx
Larynx
Trachea
Bronchus
Bronchiole
Cluster of alveoli
(INTO OVERALL LUNG)

Question 2

How does air enter into the nose

Answer 2

Air enters through nostrils, which lead into two nasal passages lined with a moist mucus membrane.

Question 3

How does the nose provide a level of protecting

Answer 3

Dust and foreign particles are trapped by hair and mucus.

Question 4

how is the trachea kept open

Answer 4

Supported by C-shaped rings of cartilage which keeps the lumen of the trachea open

Question 5

what does the trachea contain for protection and where

Answer 5

epithelium of trachea contains gland cells and ciliated cells

Question 6

what are the two types of protective cells in the trachea

Answer 6

gland cells: secrete mucus to trap dust particles and bacteria

ciliated cells: sweep dust-trapped mucus up the bronchi and trachea

Question 7

what do the gland cells of the trachea do to protect from bacteria

Answer 7

secrete mucus to trap dust particles and bacteria

Question 8

what do the ciliated cells of the trachea do to protect from bacteria

Answer 8

sweep dust-trapped mucus up the bronchi and trachea

Question 9

how does the trachea divide up

Answer 9

The trachea divides into two tubes (bronchi)

Question 10

how does bronchus further divide

Answer 10

Each bronchus carries air into the lung and branches repeatedly, giving rise to numerous bronchioles.
Each bronchiole ends in a cluster of air sacs (alveoli)

Question 11

what are the alveoli

Answer 11

a cluster of air sacs (alveoli)

Question 12

where does gas exchange take place

Answer 12

Gas exchange takes place through the walls of the alveoli

Question 13

what do the numerous alveoli in the lungs do

Answer 13

provide a large surface area to volume ratio for efficient gaseous exchange

Question 14

what does the walls of alveoli do to make gas exchange efficient

Answer 14

wall of the alveolus is only one cell thick. This provides a short diffusion distance for gases, ensuring faster rate of diffusion.

Question 15

what does the blood supply of the alveoli do to make gas exchange efficient

Answer 15

The walls of the alveoli are richly supplied with blood capillaries. The flow of blood maintains the concentration gradient for diffusion of:
o oxygen from alveoli to blood capillaries
o carbon dioxide from blood capillaries to alveoli

Question 16

what is the gradient of diffusion within the alveoli between

Answer 16

concentration gradient for diffusion of:
o oxygen from alveoli to blood capillaries
o carbon dioxide from blood capillaries to alveoli

Question 17

what is the chest wall supported by

Answer 17

chest wall is supported by the ribs

Question 18

how are ribs attached to help support the chest wall and what does this facilitate

Answer 18

attached dorsally to the vertebral column such that they can move up and down.

Question 19

how many ribs do humans have

Answer 19

Humans have 12 pairs of ribs.

Question 20

what are the ribs of a human attached to

Answer 20

The first 10 pairs are attached ventrally to the sternum.

Question 21

what are the muscles in between the ribs

Answer 21

Two sets of muscles:
o external intercostal muscles
o internal intercostal muscles

Question 22

how does the muscles in between the ribs interact

Answer 22

two sets of ribs:
o external intercostal muscles
o internal intercostal muscles

antagonistic muscles: when one relaxes the other muscle contracts

Question 23

how is the thorax separated from the abdomen

Answer 23

Thorax is separated from abdomen by the diaphragm (a dome-shaped sheet)

Question 24

describe how the respiratory system interacts during inhalation

Answer 24

• Diaphragm muscle contracts and diaphragm flattens.
• External intercostal muscles contract, internal intercostal muscles relax.
• Ribs move upwards and outwards. Sternum moves up and forwards.
• Volume of thoracic cavity increases.
• Lungs expand and air pressure inside decreases.
• Atmospheric pressure is higher than pressure in lungs, which forces air into lungs.

Question 25

describe how the respiratory system interacts during exhalation

Answer 25

• Diaphragm muscle relaxes and diaphragm arches upwards.
• Internal intercostal muscles contract, external intercostal muscles relax.
• Ribs move downwards and inwards. Sternum moves down.
• Volume of thoracic cavity decreases.
• Lungs are compressed and air pressure inside increases.
• Pressure in lungs is higher than atmospheric pressure, which forces air out of
lungs.