Gas exchange and smoking

Question 1

Gross structure of the human gas exchange system

Answer 1

The human gas exchange system includes the trachea, the bronchioles and the alveoli. During inhalation (breathing in) the diaphragm contracts and the external intercostal muscles contract. This increases the volume and decreases the pressure in the thoracic cavity to lower than that of the atmosphere.

Question 2

Structure of the trachea

Answer 2

The trachea is composed of about 20 rings of tough cartilage. The back part of each ring is made of muscle and connective tissue. Moist, smooth tissue called mucosa lines the inside of the trachea. The trachea widens and lengthens slightly with each breath in, returning to its resting size with each breath out.

Question 3

Structure of bronchi

Answer 3

While the trachea and upper bronchi contain C-shaped cartilage, the smaller bronchi have “plates” of cartilage. As the bronchi subdivide into smaller (subsegmental) bronchi, the amount of cartilage decreases, and the amount of smooth muscle increases.

Question 4

Structure of brochioles

Answer 4

Bronchioles are approximately 1 mm or less in diameter and their walls consist of ciliated cuboidal epithelium and a layer of smooth muscle. Bronchioles divide into even smaller bronchioles, called terminal, which are 0.5 mm or less in diameter.

Question 5

Structure of alveoli

Answer 5

Each alveolus is cup-shaped with very thin walls. It’s surrounded by networks of blood vessels called capillaries that also have thin walls. The oxygen you breathe in diffuses through the alveoli and the capillaries into the blood.

Question 6

Functions of cartilage

Answer 6

Cartilage is a flexible connective tissue that keeps joint motion fluid by coating the surfaces of the bones in our joints and by cushioning bones against impact. It is not as rigid as bone, but is stiffer and less flexible than muscle tissue.

Question 7

Functions of cilia

Answer 7

The function of cilia is to move water relative to the cell in a regular movement of the cilia. This process can either result in the cell moving through the water, typical for many single-celled organisms, or in moving water and its contents across the surface of the cell.

Question 8

Functions of goblet cells

Answer 8

Goblet cells arise from pluripotent stem cells and derive their name from their goblet, cup-like appearance. The primary function of goblet cells is to secrete mucin and create a protective mucus layer.

Question 9

Functions of mucous glands

Answer 9

Mucus serves to protect epithelial cells in the linings of the respiratory, digestive, and urogenital systems, and structures in the visual and auditory systems from pathogenic fungi, bacteria and viruses. Most of the mucus in the body is produced in the gastrointestinal tract.

Question 10

Functions of smooth muscle

Answer 10

Smooth muscles move food through the digestive tract. Folds in the stomach and small intestine, which are made of smooth muscle, help the body better absorb nutrients. Smooth muscle composes all sphincters in the digestive system. In the bladder, smooth muscle helps to push out urine.

Question 11

Functions of elastic fibres

Answer 11

The main components of elastic fibers, elastin and fibrillin-containing microfibrils play a structural and mechanical role in the arteries and their essential function is to provide elasticity and resilience to the tissues.

Question 12

Process of gas exchange between air in the alveoli and the blood

Answer 12

Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.

Question 13

Effects of tar

Answer 13

A chemical substance made when tobacco is burned. Tar contains most of the cancer-causing and other harmful chemicals found in tobacco smoke. When tobacco smoke is inhaled, the tar can form a sticky layer on the inside of the lungs. This damages the lungs and may lead to lung cancer, emphysema, or other lung problems.

Question 14

Effects of carbon monoxide

Answer 14

The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. CO symptoms are often described as “flu-like.” If you breathe in a lot of CO it can make you pass out or kill you.

Question 15

Effects of nicotine

Answer 15

Nicotine is known to cause decreased appetite, heightened mood, increased heart rate and blood pressure, nausea, diarrhea, better memory, and increased alertness.

Question 16

Chronic obstructive pulmonary disease (COPD)

Answer 16

The name for a group of lung conditions that cause breathing difficulties.
It includes:
-emphysema – damage to the air sacs in the lungs.
-chronic bronchitis – long-term inflammation of the airways.

Question 17

Short-term effects of nicotine on the cardiovascular system

Answer 17

Nicotine causes your blood vessels to constrict or narrow, which limits the amount of blood that flows to your organs. Over time, the constant constriction results in blood vessels that are stiff and less elastic. Constricted blood vessels decrease the amount of oxygen and nutrients your cells receive.

Question 18

Short-term effects of carbon monoxide on the cardiovascular system

Answer 18

Carbon monoxide could manifest its toxic effects on the heart and blood vessels in two ways, either by causing acute, short-term effects on oxygen delivery or by contributing to the development of cardiovascular diseases such as atherosclerosis.