lecture 24

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Questions and Answers

What is the primary reason why terrestrial organisms were able to increase their uptake of oxygen?

Because it requires less energy to pump oxygen in air

Because oxygen is more concentrated in air (correct)

Because air is 50 times more viscous than water

Because water is 800 times more dense than air

What is the function of spiracles in insects?

To pump oxygen to the cells

To regulate the movement of CO2 out

To provide a direct path for air to enter their system (correct)

To filter air before it reaches the tracheae

What is the purpose of tidal ventilation in vertebrates?

To pump air into the cells

To ventilate air directly to the cells

To move air with high O2 in and air with high CO2 out (correct)

To move air with high CO2 out

Why is it easier to pump oxygen in air compared to water?

Because it requires less energy to pump oxygen in air Signup and view all the answers

What is the function of tracheae in insects?

To ventilate air directly to the cells Signup and view all the answers

What is the primary mechanism of gas exchange in the respiratory system?

Diffusion Signup and view all the answers

What is the primary function of the gills in fish?

To extract oxygen from water Signup and view all the answers

What is the term for the movement of fluids down a pressure or temperature gradient?

Bulk Flow Signup and view all the answers

What is the name of the thin, sheet-like structures that extend up from each gill filament and are lined with capillaries?

Lamellae Signup and view all the answers

What is the term for the mechanism by which dissolved gases or electrolytes in one closed system are diffused into a second system using diffusion?

Counter Current Exchange Signup and view all the answers

What is the primary difference between blood and hemolymph?

Blood is used in closed circulatory systems, while hemolymph is used in open circulatory systems Signup and view all the answers

What is the primary function of the diaphragm during inhalation?

It moves posteriorly and expands the lungs Signup and view all the answers

What is the term for the amount of air you generally breathe at rest?

Tidal volume Signup and view all the answers

What is the function of the larynx in the throat?

It helps in separating swallowing from breathing Signup and view all the answers

What is the purpose of the surfactant in the alveoli?

To reduce mucus surface tension Signup and view all the answers

What is the function of the carotid bodies and aortic bodies?

To detect variation in CO2, H+, and O2 in the blood Signup and view all the answers

What is the term for the percentage of red blood cells in your blood?

Hematocrit Signup and view all the answers

What is the finest subdivision of the secondary bronchi?

Terminal bronchioles Signup and view all the answers

What is the function of the pulmonary capillaries?

To supply each alveolus with blood Signup and view all the answers

What happens to the diaphragm during exhalation?

It moves anteriorly and contracts the lungs Signup and view all the answers

What is the term for the ability of a substance to be dissolved in water?

Solubility Signup and view all the answers

Study Notes

Respiratory System

Gas exchange in large organisms depends on two processes: diffusion (movement from high to low concentration) and bulk flow (movement of fluids down a pressure or temperature gradient)
Respiratory system has two main components: diffusion and bulk flow
Diffusion: gases move from high pressure to low pressure, dependent on partial pressure (P)
Bulk flow: moves environmental medium across specialized respiratory surface and circulatory fluid (blood or hemolymph) through the body

Blood vs Hemolymph

Blood: circulatory fluid in closed circulatory systems containing blood cells that deliver oxygen
Hemolymph: fluid that many invertebrates use to circulate oxygen and/or nutrients through an open circulatory system

Respiration

Gas exchange occurs in respiratory organs such as gills, lungs, or tracheae
Gills: extract oxygen from water using thin, sheetlike structures (lamellae) with capillaries that bridge an artery to a vein
Counter-current exchange: mechanism by which dissolved gases or electrolytes in one closed system are diffused into a second system using diffusion

Terrestrial Respiration

Terrestrial organisms can increase oxygen uptake by ~50x due to higher oxygen concentrations in air
O2 in air diffuses ~8000x faster than in water
Water is 800 times more dense and 50 times more viscous than air, requiring less energy to pump oxygen

Insect Respiration

Insects use spiracles (openings along the sides of their abdomen) to provide a direct path for air to enter their system
Network of tracheae (branching tubes) ventilate air directly to their cells

Vertebrate Respiration

Tidal ventilation: lungs inflate and deflate to move air with high O2 in and air with high CO2 out
Inhalation: air enters the lungs, lungs expand, and the diaphragm moves posteriorly
Exhalation: gases leave the lungs, the lungs contract, and the diaphragm moves towards the head

Respiratory System Anatomy

Mouth and nasal passages
Larynx: organ in the throat made of cartilage, containing vocal cords, and helps separate swallowing from breathing
Trachea: central airway leading to the lungs
Primary bronchi: fork in the trachea that goes to each lung
Secondary bronchi and bronchioles: finer subdivisions of the secondary bronchi
Terminal bronchioles: less than 1 mm diameter
Respiratory bronchioles: lead to alveoli where gas exchange takes place
Alveoli: sacs where gas exchange takes place
Pulmonary capillaries: supply each alveolus with blood, allowing for rapid diffusion of gases

Control of Breathing

Carotid bodies: sensors in the carotid arteries that detect variation in CO2, H+, and O2 in the blood
Aortic bodies: sensors in the aorta that detect variation in CO2, H+, and O2 in the blood
They send signals to the brainstem, which sends action potentials to motor neurons that control breathing rate