2.46 - 2.50 ; Gas exhange

What are the main components of the human breathing system?

The human breathing system consists of the thorax, ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, and alveoli.

What features do gas exchange surfaces have in common?

They have a large surface area, thin walls, good ventilation, and a good blood supply.

How does inhalation occur in the breathing process?

During inhalation, the diaphragm contracts and flattens, and the external intercostal muscles contract to pull the ribs up and out, increasing the volume of the chest cavity, decrease in air pressure inside the lungs compared to rest of the body. Air is pulled in

What happens during forced exhalation?

During forced exhalation, both the external and internal intercostal muscles work antagonistically to pull the ribs down and in, decreasing the volume of the thorax.

What adaptations do alveoli have for efficient gas exchange?

Alveoli have a large surface area to volume ratio, thin walls to minimise diffusion distance, good ventilation and an excellent blood supply to keep oxygen levels high and CO2 level low, and a layer of moisture to assist in gas diffusion.

What defines emphysema and its impact on the lungs?

Emphysema is a condition where the elastic fibers in alveoli are broken down, reducing their elasticity and surface area for gas exchange making patients breathless and wheezy.

What physiological changes occur during exercise that affect breathing rate?

Exercise increases breathing frequency to supply more oxygen for respiration

How is oxygen debt related to breathing after exercise?

After exercise, the breathing rate remains high to repay the oxygen debt caused by lactic acid buildup in muscles.

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Intercoastal Muscles

Muscles between the ribs which control the movement causing inhalation and exhalation

Diaphragm

Sheet of tissue at the bottom which allows the thorax to change volume during inhalation and exhalation

Ribs

Bone structure that protects the lungs and other internal organs

Trachea

Windpipe that connects the mouth and nose to the lungs

Alveoli

Tiny air sacs where gas exchange takes place

Bronchi(plural)

Large tubes branching off the trachea into two bronchus’s

Bronchioles

Broncus splititng into smaller tubes inside the lungs

Plueral cavity

The fluid filled inside the lungs which reduces friction and allows the lung to move freely

How does exhalation occur in the breathing process?

During exhalation, the diaphragm relaxes and moves back into its dome shape, while the intercostal muscles relax, allowing the ribs to move down and in, decreasing the volume of the chest cavity and increasing air pressure inside the lungs, pushing air out.

Smoking harmul chemicals: Nicotine

Narrows blood vesells and increases heart rate, causing blood clots in patients which lead to heart attack or stroke

Smoking harmful chemicals: Carbon monoxide

Carbon monoxide binds irreversibly to haemoglobin, reducing the capacity of blood to carry oxygen, putting more strain on the breathing system as breathing frequency and depth need to increase to supply the same amount of oxygen. It means that the circulatory system needs to pump blood faster, raising blood pressure and increasing the risk of coronary heart disease and stroke.

Smoking harmful chemicals: Tar

Tar increases the chances of cancerous cells developing in the lungs

What is chronic bronchitis and how does it affect the lungs?

When tar stimulates goblet cells to produce more mucus. This mucus builds up and blocking bronchioles causing infection and damaging cilia.

What is a smokers cough?

It is an attempt to remove mucus

Alternate substance used to test for CO2 aside from limewater?

Sodium bicarbonate solution