Gas Exchange/Excretion

What is the primary purpose of gas exchange in organisms?

To exchange carbon dioxide for oxygen.

What are the requirements for a respiratory surface?

It needs to be thin, moist, and in contact with gases.

Why do large animals require a transport system for gas exchange?

Because they need vessels and blood with an oxygen-carrying molecule, a respiratory pigment.

What is the respiratory surface in humans?

The lungs.

What are the main components of inhaled air?

79% nitrogen gas, 20.9% oxygen, 0.04% carbon dioxide.

What happens to the composition of air during exhalation?

Exhaled air contains 79% nitrogen, 16.3% oxygen, and 4.5% carbon dioxide.

List the sequence of structures that air passes through from the nose to the alveoli.

Nose, pharynx, larynx, trachea, bronchi, bronchioles, alveoli.

What is the function of the alveoli?

The site of gas exchange.

What is tidal volume?

The amount of air inhaled or exhaled during normal resting breathing, approximately 500 mL.

What is emphysema and its cause?

A condition resulting from destruction of alveoli walls, often due to inhaling multiple toxins.

What is the role of the medulla in breathing regulation?

It controls the involuntary process of breathing in or out.

What is external respiration?

Gas exchange in the alveoli with capillaries.

How is oxygen transported in the blood?

Oxygen combines with hemoglobin to form oxyhemoglobin.

What percentage of carbon dioxide is transported as bicarbonate in plasma?

70%.

What does the term 'excretion' refer to?

The elimination of metabolic waste products from the body.

What is the main role of the kidneys in the excretory system?

To remove waste from cellular metabolism from the blood.

What are nephrons responsible for?

Filtering waste from the blood in the kidneys.

What causes kidney stones?

Crystallization of substances such as calcium that precipitate out of the urine.

What is the function of the liver in the excretory system?

Detoxification of blood and removal of harmful substances.

Why do the lungs play a role in excretion?

Because they expel carbon dioxide and water vapor.

How do skin and sweat glands contribute to excretion?

By excreting urea and salts in sweat.