BIO 461 - Exam 1 - Respiratory System PowerPoint

Question 1

What is the purpose of the respiratory system?

Answer 1

To exchange physiologically important gases (O2 and CO2) between the blood and environment.

Question 2

Four steps involved in moving gases between the environment and the cells:

V
E
T
G

Answer 2

(1) Ventilation
(2) External respiration
(3) Transport
(4) Gas diffusion

(1) Ventilation: breathing – taking a mixed gas out of the air and moving it, in its entirety (not partitioning it), from the environment to the inside of your lungs.
 Involved in the respiratory system
(2) External respiration:
∙ Measuring respiratory rate is impossible. It is the ventilatory rate they want you to measure. Ventilation is moving the whole air a distance by unchanged vs diffusion respiratory rate is the movement of individual molecules (oxygen and carbon dioxide) across a barrier (respiratory membrane) from inside the lung to inside the bloodstream.
 Involved in the respiratory system
(3) Transport: hemoglobin is going to carry it.
(4) Gas diffusion or internal respiratory rate: blood from the systemic capillaries to the tissues.

Question 3

What are the three types of respiration?

Answer 3

(1) External: between lungs and the blood.

(2) Internal: between blood and the cells.

(3) Cellular: conversion of nutrients to ATP – usually aerobically in the presence of oxygen.

Question 4

The purpose of the upper ventilatory tract of the mammal respiratory system is:

Answer 4

warm, moisten, clean, and transport air.

Question 5

Why not have a complete trachea ring? Why have a Trachealis muscle?

Answer 5

Your neck is only so much in diameter, and does not expand well. If it does not have flexibility to swallow food, it could get stuck in there, which can affect both breathing and swallowing. The esophagus can extend to some point into the tracheal lumen, so you can take larger swallows.

(1) By having this be incomplete, it enables the esophagus, when swallowing, to briefly stretch into this space. When it is relaxed, you have an open lumen, air is going to pass though there.

(2) When it is contracted, the space is greatly reduced, increasing resistance – helping to cough and clean the wall of the traches (cilia) off from dirt.

Question 6

What is the purpose of the lung?

Answer 6

Gas exchange (external respiration) via passive diffusion – it is going to move oxygen from the lung to the bloodstream and attach to hemoglobin and transported through the body.

Question 7

Diffusion rate affected by:

Answer 7

1) surface area
2) boundary thickness (respiratory membrane 0.6 microns thick)
3) concentration gradient – the greater the gradient, the faster we are going to get flow across the membrane.
4) gas solubility (if moving into a liquid)

Question 8

Slide 5

Answer 8

Mammal Respiratory System Ventilation - a bellows system
∙ Flow: ∆P/R: Whether it is the flow of liquids or gases, it does not matter. Pressure gradient over resistance. The greater the pressure gradient, the greater the flow, the reduced resistance, the greater the flow. Either reduce R or increase ∆P. If you cannot increase environmental pressure, you must increase internal pressure to have a pressure gradient and flow will go out of the lungs and vice versa.
∙ Boyle’s Law: P ∝ 1/V: Increase pressure with decrease volume. We want to reduce pressure in our lungs to get flow in – according to Boyle’s Law, we must increase volume to decrease the pressure in the lung (lower pressure than outside) and expanding the size of your lung will decrease the pressure (pressure gradient) and get flow.

Question 9

What are the two disadvantages of a bellows system?

Answer 9

1) incomplete air clearance - residual air & dead space air & fresh air
2) intermittent delivery of fresh air to the lung

Fish
∙ Water needs to flow 10-20X faster than blood, due to its low O2 content.
∙ Fish extract 80% of oxygen in water; mammals only 25% of oxygen in air!

Question 10

What are the two primary challenges fish must face getting oxygen out of the water?

Answer 10

(1) Water is more dense (higher viscosity) and less oxygen concentration than air.

If we have a more viscous material, the respiratory membranes must be thin, or else they would get damaged by water passing over them.

(2) The thickness of the barrier influences the rate of diffusion (slow it), which is already going to be slow due to the concentration gradient between the water and the environment.

Question 11

How to fish maximize diffusion?

Answer 11

The gills have filaments that have lamellae and secondary lamellae with enormous surface area on the gills that increases diffusion because there is more space to which you can diffuse.

Question 12

What is their oxygen demand relative to mammals?

Answer 12

Lower. They do not need to move as much as mammals.

Question 13

How do fish move water across these respiratory membranes?

Compare bellow ventilation and moving water across membranes * maybe test question.

Answer 13

1) Ram ventilation: open your mouth and ram yourself through the water and force the water to go through.
2) Buccal pumping:
They cover their gills (operculum outer shield) contract muscles that expand the mouth that decreases volume & pressure (Boyle’s Law) so water flows into the mouth.

Once water fills the mouth, they close the buccal cavity, reducing volume and increase the pressure, and that is going to push the water out across the gills.

Humans are a bellows ventilator; air goes in, sits static in our alveoli, and air goes out (dead space – residual volume). If you are starting with very low oxygen content in the water, you do not want to sit with air stagnant inside against your respiratory membranes; the oxygen content will get lower.
∙ You must be moving all the time. You will see small holes inside the head called spiracles (pumps). Enough water can be pushed to pump it across your gills to satisfy your oxygen demands while an animal is sitting doing nothing. More developed in fish that do not have a buccal pump. Most developed in rays – sits on the bottom vs a shark and its mouth are in the sand.

Question 14

If amphibians are not pushing water across the respiratory membranes, why have something that is so thick?

Answer 14

Much higher demand for oxygen. They must increase their surface area. They must get as much oxygen as possible. There is not much selection for being able to move oxygen more quickly through the circulation, so there is no selection for thinner membranes that you see in mammals (respiratory membranes 0.6 millimeters). That is why they have the same membrane thickness as fish.

Question 15

Slide 11

Answer 15

Amphibians have a bellow system like humans. Frogs have no ribs, and therefore, no intercostal muscles or a diaphragm. They have no way of sucking air into their thorax, because they have no way of expanding their thorax. They buccal pump through their mouth; have muscles and cartilage to help move the air (just like lung fish). This does not come into contact with the respiratory membranes, so the animal must close the nostrils, contract other muscles associated with that, and push the air into the lungs. Humans just expand the thoracic cavity to expand the lungs.

Question 16

Diffusion rate of cutaneous respiration (vs. lungs) in frogs:

Answer 16

See notes (page 12)

Question 17

Why have cutaneous respiration if you have slower diffusion?

Answer 17

You do not need muscles to pump. Cannot inhale water through the lungs while submerged.

Question 18

Plethodontidae (lungless salamanders)

What are some characteristic to breathe through your skin / What are the requirements for terrestrial life without lungs?

Answer 18

high surface area (elongated, small), moist skin, low activity.

Low activity, long and skinny give more surface area, skin must be moist to move things across the respiratory membrane.

Question 19

Plethodontidae (lungless salamanders)

What are the benefits of not having lungs?

Answer 19

Slow animal becomes a fast predator!

Create a lot of space in the body cavity where the lungs used to be. Have a rapidly protrude able tongue fill that space, can use the same bony attachments to throw the tongue and bring it back. Can hunt fast moving insects. Nostrils are used for sensing chemicals.

Answer 20

Lizard lung - bellows ventilation
∙ Have ribs – intercostal muscles – expand thorax –breath without buccal pumping.
∙ No diaphragm, so only costal muscle contractions
∙ Glottis (i.e., tracheal opening) is closed when relaxed, actively open it – no epiglottis to close tracheal opening.
∙ In all lizards, exhalation is always an active process! (e.g., requires energy).
∙ Greater number of faveoli, so greater surface area than amphibian lungs.

Answer 21

Snake respiratory tract
The left lung in most snakes is vestigial; it is a dead-end pocket. Instead, they have a large right lung. At the end of the lung (it is called a lung due to the good vasculature, respiratory membranes, and move oxygen – high surface area) is an air sac that is relatively smooth and poorly vascularized that hold air, but does not have respiration.

Question 22

Why have it if it cannot respire?

Answer 22

There is not an enormous demand for oxygen – they can eat one thing for hours – and it is hard to breathe. The beat of the heart helps mix the air between the air sac and lungs. Increases the time it takes to deplete the air inside the snake’s body.

They also have forward-located glottis (like a snorkel) to breathe air while they are swallowing, and complete tracheal rings so the glottis is not going to get crushed when they have an animal in their throat.

Answer 23

Turtle ventilation - bellows ventilation
∙ No diaphragm & ribs incorporated into shell. No intercostal muscles to expand the chest. They breathe using muscles to expand the cavity (transverse abdominus) where the lung is and collapses it (oblique abdominal muscle).

Answer 24

Crocodilian ventilation
∙ Have ribs, but tough skin and no diaphragm
∙ Hematic Piston:
∙ Palatal valve (prevents aspiration of H2O): Blocks water from going into the stomach when the animal is under water with its mouth open.
∙ Caudal Sac: When they inhale, air can go two places (1) fill the caudal sac (no respiratory membrane, no vasculature, no diffusion) or (2) air can go into the lungs and across the parabronchi (location of respiratory membrane). Significance: when they exhale, they must squeeze the piston (move forward), lung volume is going to shrink, and air in the caudal air sac is going to across and out. During inhalation, fresh air going across the respiratory membrane and during exhalation, you have fresh air going across the respiratory membranes. Enables a high oxygen concentration gradient but low surface area.