4:5 Respiratory System

Question 1

What are the two key features of the respiratory system?

Answer 1

Existence of a ventilation mechanism

Large surface area to volume ratios for gaseous exchange

Question 2

What does the lower respiratory tract consist of?

Answer 2

Trachea (windpipe), lungs, bronchi(singular bronchus) and bronchioles.

Question 3

What does the upper respiratory track consists of?

Answer 3

The nostrils, nasal cavities, pharynx (throat), larynx (voice box, lower)

Question 4

Name all parts of the human lower respiratory tract (downwards)

Answer 4

Trachea
Bronchial tree
Bronchioles
Terminal bronchioles
Respiratory bronchioles
Alveolar sacs

Question 5

What adaptations does the trachea have to ensure that clean air entered the lungs smoothly?

Answer 5

It is supported by C-shaped rings of cartilage, which keeps the lumen of trachea open.

The lumen is lined by ciliated epithelium

The ciliated epithelium has goblet cells and ciliated cells

Goblet cells secrete mucus to trap dust particles and bacteria

Ciliated cells have hair like structures called cilia which sweep dust trapped mucus up the trachea

Question 6

Describe alveoli (singular: alveolus)

Answer 6

It is divided from the bronchioles from bronchus branches. Alveoli are surrounded by capillaries. The inhaled oxygen passes into it and diffuses through the capillaries into the arterial blood.

Question 7

4 adaptations of alveoli?

Answer 7

1. Numerous alveoli so that when combined there is a large surface area for high rate of gaseous exchange
2. They are surrounded by a dense network of blood capillaries. Allows a diffusion gradient across alveolar walls.
3. Very thin cell walls that are only 1 cell thick. Blood capillaries around it also have 1 cell thick walls. It allows rapid diffusion.
4. Lined with a thin layer of moisture to allow gases to dissolve into and out of blood capillaries.

Question 8

Parts in human body that help with breathing?

Answer 8

Diaphragm, ribs, internal intercostal muscles, external intercostal muscles

Question 9

How does inhalation and exhalation change the thoracic volume and pressure?

Answer 9

Inhalation: increase in thoracic volume, reduction in gas pressure in alveoli
Exhalation: decrease in thoracic volume, increase in gas pressure in alveoli.

Question 10

What is responsible for the largest change in thoracic volume

Answer 10

The diaphragm.

Question 11

Describe what happens in inhalation?

Answer 11

1. Diaphragm contracts and flattens
2. External intercostal muscles contract while internal intercostal muscles relax, causing rib cage to swing upwards and outwards
3. Volume of thoracic cavity increases, causing pressure in lungs to decrease below atmospheric pressure
4. Pressure difference causes air to flow into lungs until pressure inside lungs rises to atmospheric pressure.

Question 12

Describe what happens in forced exhalation?

Answer 12

1. Internal intercostal muscles contract, pushing rib cage downwards and inwards
2. Contraction of abdominal muscles causes diaphragm to arch upwards.
3. Volume of thoracic cavity decreases, causing pressure in lungs to increase above atmos.
4. The pressure difference causes air to flow out of lungs until pressure lowers to atmos.

Question 13

Describe what happens in passive exhalation?,

Answer 13

1. intercostal muscles and diaphragm relax, and return to resting position.
2. Relaxation of diaphragm causes it to arch upwards.
3. Volume of thoracic cavity decreases, causing pressure in lungs to increase above atmos.
4. The pressure difference causes air to flow out of lungs until pressure lowers to atmos.

Question 14

Properties of nicotine?

Answer 14

Addictive

Makes blood clots easily

Question 15

Effects of nicotine on health

Answer 15

Increases blood pressure and heart rate
Increased risk of blood clots and plaque deposits on walls of coronary arteries
Increased risk of coronary heart disease

Question 16

Properties of tar?

Answer 16

Contains compounds which induce uncontrolled cell division.

Paralyses cilia lining air passages

Question 17

Effects of tar on health

Answer 17

Blocks alveoli, reduces efficiency of gas exchange
Results in inability to remove dust particles trapped in mucus lining airways, resulting in shortness of breath
Increases risk of chronic bronchitis and emphysema.

Question 18

Properties of carbon monoxide

Answer 18

Odourless gas
Combines with haemoglobin to form carboxyhaemoglobin, reducing efficiency of oxygen transported by RBC
Increases rate of fatty deposited on inner arterial wall, damaging epithelium of blood vessels
Increase risk of coronary heart disease.

Question 19

Effects of carbon monoxide on health.

Answer 19

Reduced ability of blood to transport oxygen

Causes lumen of arteries to become narrower, increasing blood pressure and risk of blood clotting in arteries

Question 20

Properties of irritants in tabacco?

Answer 20

Paralyse cilia lining airways

Question 21

Effects of irritants from tobacco?

Answer 21

Paralysis of cilia reimst in inability to remove dust particles trapped in mucus lining airways, causing shortness of breath

Question 22

Describe chronic bronchitis

Answer 22

It is a long term inflammation off the epithelium lining the bronchi. this results in increased production of mucus and paralysis of the cilia in the epithelium. Mucus and dust particles cannot be removed. Airways become blocked.

Symptoms: person coughs persistently to clear airways, breathing is difficult

Question 23

Describe emphysema

Answer 23

They suffer from coughing that damages the partition walls in the alveoli. This results in a decrease surface area for gas exchange. This is caused by chemicals in tobacco smoke entering the lungs and triggering an immune response leading to the destruction of the lung tissue. Lungs lose their elasticity and become inflated with air. 

Symptoms: persistent and forceful coughing, difficulty in breathing, wheezing, severe shortness of breath