Respiratory System

Question 1

What is cellular respiration?

Answer 1

Aerobic breakdown of glucose in the mitochondria to make ATP

Question 2

What does the respiratory system allow?

Answer 2

Allows animals to move oxygen (needed for cellular resp.) into body tissues + remove CO2 (waste product of CR) from cells.

Question 3

How does respiration happen in small organisms?

Answer 3

Gases diffuse through their skin. All aquatic animals.

Question 4

Why is respiration efficient in small organisms?

Answer 4

• Large SA:Vol ratio

- Structures specialised for gas exchange e.g. spiracles, gills, lungs

Question 5

What is inspiration and what happens in the resp. system during it?

Answer 5

Inhalation

• Diaphragm and intercostal muscles contract
• Ribcage moves up and out

Question 6

What is exhalation and what happens in the resp. system during it?

Answer 6

Breathing Out

• Muscles relax
• Diaphragm moves upwards
• Ribcage moves down + out

Question 7

What are the key components of the respiratory system?

Answer 7

• Nasal Cavity
• Pharynx
• Epiglottis
• Larynx
• Oesophagus
• Trachea
• Bronchi
• Bronchioles
• Pulmonary Artery
• Pulmonary Vein

Question 8

What do the alveoli do?

Answer 8

POCKETS OF GAS EXCHANGE

• contains smooth muscle
• highly perfused, lots of veins + arteries
• thin-walled + moist
• slightly oil surfactant (forms bubbles + breaks up oil) prevents alveolar walls from collapsing + sticking together

Question 9

What are the 4 things that happen with the lungs and the heart?

Answer 9

1. Gases move in and out of lungs by breathing
2. O2 and CO2 are exchanged in the lungs by diffusion
3. Gases are dissolved in the blood + transported by the circulatory system
4. O2 and CO2 are exchanged

Question 10

What does the alveolus do?

Answer 10

SITE OF GAS EXCHANGE

• Respiratory surface made up of the alveoli + capillary walls
• Walls of capillaries and alveoli may share the same membrane

Question 11

Oxygen Transport:

Answer 11

O2 diffuses through lung capillary wall, is bound to Hb (4 x O’s) and carried to tissues, where it is then diffused through tissue capillary walls.

Hb also contains Iron that invading cells want but it is tightly bound.

Question 12

CO2 Transport:

Answer 12

Can dissolve in plasma
around 70% forms bicarbonate ions

• Some CO2 binds to Hb for transport