SBI3U - Respiratory and Digestive Systems

What is aerobic cellular respiration?

A process where cells use oxygen to release energy from glucose.

What is the equation for aerobic respiration?

Glucose + O₂ → CO₂ + H₂O + ATP

What is ATP?

Adenosine triphosphate; the energy currency of the cell.

What is gas exchange?

The movement of oxygen into the body and carbon dioxide out.

Where does gas exchange occur in the lungs?

In the alveoli.

What is the respiratory membrane?

A thin membrane that allows diffusion of O₂ and CO₂.

Why are alveoli efficient for gas exchange?

Thin walls, moist surface, large surface area, many capillaries.

What is the function of the nose in respiration?

Filters, warms, and moistens air.

What is the function of the trachea?

Conducts air to the bronchi and stays open with cartilage rings.

What do bronchi and bronchioles do?

Carry air deeper into the lungs and regulate airflow.

What muscle is mainly responsible for breathing?

The diaphragm.

What happens to the diaphragm during inhalation?

It contracts and moves downward.

What happens to lung pressure during inhalation?

It decreases.

What happens during exhalation?

Diaphragm relaxes, lung volume decreases, air exits.

What muscles lift the rib cage during inhalation?

External intercostal muscles.

Which muscles are used during forced exhalation?

Internal intercostal muscles.

Where is breathing controlled in the brain?

Medulla oblongata.

What chemical mainly controls breathing rate?

Carbon dioxide (CO₂).

What happens when CO₂ levels increase?

Breathing rate increases.

Where does gas exchange occur in body tissues?

Between blood and body cells.

What is the function of hydrochloric acid in the stomach?

Kills bacteria and activates enzymes.

What enzyme digests proteins in the stomach?

Pepsin.

What does mucus do in the stomach?

Protects the stomach lining from acid.

What organ produces digestive enzymes and hormones?

The pancreas.

Where does the pancreas release digestive enzymes?

Into the duodenum.

What is the function of bicarbonate from the pancreas?

Neutralizes stomach acid.

What hormone does the pancreas release to regulate blood sugar?

Insulin.

What does insulin do?

Converts glucose into glycogen for storage.

What is the main function of the liver in digestion?

Produces bile.

What does bile do?

Breaks fat into smaller droplets (emulsification).

Where is bile stored?

Gall bladder.

Where is bile released?

Duodenum.

What are gallstones?

Crystals of bile salts formed around cholesterol.

What is jaundice?

Build-up of bile pigments in the blood.

What is cirrhosis?

Breakdown of liver cells due to toxins.

Where is glycogen stored?

Liver and muscles.

What enzyme begins carbohydrate digestion in the mouth?

Salivary amylase.

What enzyme continues carbohydrate digestion in the small intestine?

Pancreatic amylase.

What enzymes break disaccharides into monosaccharides?

Disaccharidases.

Final product of carbohydrate digestion?

Monosaccharides.

Where does protein digestion begin?

Stomach.

What enzyme breaks proteins into polypeptides?

Pepsin.

What enzyme produces amino acids in the small intestine?

Pancreatic carboxypeptidase.

Final product of protein digestion?

Amino acids.

What must happen before fats can be digested?

Emulsification by bile salts.

What enzyme digests fats?

Pancreatic lipase.

Final products of fat digestion?

Glycerol and fatty acids.

What enzyme digests nucleic acids?

Pancreatic nucleases.

What breaks nucleotides into smaller components?

Nucleotidases and phosphatases.

Final products of nucleic acid digestion?

Nitrogen bases, sugars, phosphates.

What is asthma?

A chronic condition where bronchioles become inflamed and narrowed, making breathing difficult.

What causes airway narrowing in asthma?

Smooth muscle contraction, inflammation, and excess mucus.

What is bronchitis?

Inflammation of the bronchi, often caused by infection or smoking.

What is emphysema?

A disease where alveoli walls break down, reducing surface area for gas exchange.

How does emphysema affect breathing?

Makes exhalation difficult and reduces oxygen intake.

What is COPD?

Chronic Obstructive Pulmonary Disease; includes chronic bronchitis and emphysema.

Main cause of COPD?

Long-term smoking.

What is pneumonia?

Infection where alveoli fill with fluid or pus.

What is lung cancer?

Uncontrolled growth of abnormal cells in lung tissue.

What is cystic fibrosis?

A genetic disorder causing thick, sticky mucus in the lungs.