Biology 2601A/B Lecture Notes - Lecture 1: Mass Diffusivity, Partial Pressure, Osculum

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10 Dec 2016

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Around them allowing diffusion to bring more oxygen towards the mitochondria. Gas exchange i: principles & breathing in water. Metabolism is dependent on the exchange of oxygen and carbon dioxide from the environment. Plants photosynthesis gets co2 in and o2 + water out. Mitochondria for plants and animals o2 in and co2 + water out. A sink is a term for something absorbs or takes up a solute from its environment mitochondria are an oxygen sink source is the air around it, depleting the oxygen. A whale wouldn(cid:495)t be able to maintain its metabolic rate if only relying on diffusion of oxygen (big organism), but if a small organism, its possible that you could rely on diffusion to a larger extent. Large animals have a small surface area to mass/volume ratio and small animals have large surface area to mass/volume ratios. Across a cell membrane, distance is small and diffusion can occur effectively.

Related Questions

The Cambrian explosion is a prime example of ________________.

		mass extinction
		evolutionary stasis
		a large meteor impact
		adaptive radiation

1 points

QUESTION 2

Most animals are viviparous.

True

False

1 points

QUESTION 3

The first phylum with ganglia in their nervous system are the ________________________.

		Mollusca
		Nematoda
		Bivalvia
		Platyhelminthes

1 points

QUESTION 4

The last common ancestor of all animals was probably a _____________________.

		a unicellular worm
		multicellular algae
		flagellated protist
		multicellular fungus

1 points

QUESTION 5

You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile by use of many short extensions of the cytoplasm. It has well-developed organelles and two nuclei, one large, one small. The organism is most likely to be a ______________.

		foraminifera
		radiolarian
		ciliate
		flagellate

1 points

QUESTION 6

Which of the following organisms would you expect to have the largest surface-area-to-volume ratio? Assume that all of the following are the same total length.

		A mollusc
		A nematode
		A platyhelminth
		Not enough information to determine.

1 points

QUESTION 7

If the animal is a hermaphrodite, it is said to be _______________.

		dioecious
		eutelic
		monoecious
		trioecious

1 points

QUESTION 8

A terrestrial animal species is discovered with the following larval characteristics: exoskeleton, system of tubes for gas exchange and segmentation. A knowledgeable zoologist should predict that the adults of this species would also feature ____________.

		eight legs
		two pairs of antennae
		a sessile lifecycle
		an open circulatory system

1 points

QUESTION 9

The Phylum Echinodermata exhibits metamerism.

True

False

1 points

QUESTION 10

The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that _____.

		a larger volume-to-surface area ratio is adaptive in many mammals
		evolution generally progresses toward some goal
		evolution tends toward increased complexity or increased size
		in particular environments, similar adaptations can be beneficial to more than one species

Complete Question Text:

1. A patient comes to a doctor complaining of muscle cramping.As part of her examination, the doctor notes that the patient has aslow pulse. Additionally, in the past year the patient has brokenher hand and her arm in seemingly minor falls. What variable do youpredict the patient is having trouble regulating?

Fat
K+
ATP
Ca2+

2. Allen's rule is a biological rule that states that the limbsof warm blooded animals that live in colder climates are differentthan the limbs of the same species of animals in warmer climates.In what way do you expect them to be different and why?

Shorter because a low surface area to volume ratio is best formaintaining heat
Longer because a high surface area to volume ratio is best formaintaining heat. ????
Longer because a low surface area to volume ratio is best formaintaining heat
Shorter because a high surface area to volume ratio is best formaintaining heat.

3. Pepsin is a digestive enzyme. It is made in an inactive form,pepsinogen, which is activated by the acidity of the stomach toself-cleave (cut itself) into a formed called the cleaved molecule.This cleaved molecule is active pepsin, which goes on to cleavemore pepsinogen molecules, leading to a cascade of rapid pepsinactivation (and many more active pepsin molecules). This pathway isan example of:

a feedforward regulationâ¨
a positive feedback loopâ¨
a negative feedback loopâ¨
conditioning

4. The human body's arterial blood pH is tightly maintainedaround 7.4 by buffering agents that bind hydrogen ions to stop anychange in pH. If an acid-base imbalance overcomes the buffersystem, the body changes the ventilation rate, or the rate at whichgas enters or leaves the lungs. Changing the ventilation ratechanges the concentration of CO2 in the blood, which alters the pHof the blood. In this case, the muscles that control theventilation rate are acting as the:

homeostatic challenge
sensor
effector
integrator

5. The human body's arterial blood pH is tightly maintainedaround 7.4 by buffering agents that bind hydrogen ions to stop anychange in pH. If an acid-base imbalance overcomes the buffersystem, the body changes the ventilation rate, or the rate at whichgas enters or leaves the lungs. Changing the ventilation ratechanges the concentration of CO2 in the blood, which alters the pHof the blood. In this case, pH 7.4 is the:

homeostatic challenge
sensor
effector
set point

6. What is the equivalent of the mammalian mouth and nose in therespiratory system of insects?

alveoli
spiracles
tracheoles
epithelial tissue

7. For cells to maintain an appropriate solute concentration,_____ will occur; for cells to maintain an appropriate waterconcentration, _____ will occur.

diffusion, osmosis
osmosis, diffusion
diffusion, facilitated diffusion
diffusion, active transport

8. A marine fish with a cold body temperature that matches itscold surroundings is an example of

negative feedbackâ¨
regulating
conforming
homeostasis

9 Fiddler crabs are small crabs that inhabit intertidal areas.When the tide comes in, the salinity rises to 35ppt and when thetide leaves, the salinity falls to 5ppt. Fiddler crabs can maintaintheir internal salinity at 32ppt when the external environmentranges from 20-40ppt, but cannot regulate at levels higher or lowerthan this. The range of 20-40ppt is the ____________________ forthese animals.

zone of conforming
zone of stability
osmoregulator conforming capacity
positive feedback effector range

10. Imagine you are entering a darkened cavern. You are excited,but also a little nervous. Your heart rate quickens, your bloodpressure rises slightly, and your digestive system activitydecreases as blood is diverted to your musclesâall changes thatprepare you should you need to move rapidly. This type of change isan example of:

positive feedback control
negative feedback control
a failure of homeostasis
feedforward regulation

aquamarinewildebeest773

Background

Almost all animal and plant cells require oxygen and give off carbon dioxide. This is called gas exchange and it occurs by passive diffusion. Some animals do all or most of their gas exchange across their skin (for example amphibians) but they have very low metabolisms and use very little oxygen and get rid of very little carbon dioxide.

On the other hand humans (and other mammals) have very high metabolic requirements and we canât rely on gas exchange over the limited 1.5 to 2.0 square meters of our skin to get enough oxygen in and carbon dioxide out fast enough. Our gas exchange takes place across a very thin membrane in the Alveoli of the lung and the gas exchange surface in humans is estimated to be between 50 and 100 square meters, or between 25 and 67 times our skin surface area.

Our lungs provide a huge surface for gas exchange but they are a dead-end system. Once the oxygen in the lungs is used up it needs to be replenished and carbon dioxide builds up in the air spaces in the lungs and needs to get out. This is where the diaphragm and a few of the skeletal muscles become important. In its relaxed state the diaphragm is at its longest and the space in the thoracic cavity (and the lungs) is small. When the diaphragm contracts it shortens, which increases the volume of the thoracic cavity (and the lungs). The increase in size means the pressure is lower in the lungs than outside so air comes into the lungs (inhalation). As the diaphragm relaxes, the lungs decrease in size enough that the pressure inside the lungs is higher than the external air pressure so air comes out (exhalation).

Introduction

In this lab you will be building a model of a lung and experimenting with different ways to breath.

Supplies:

In the Lab Kit

One round 9" balloon (one lung, we donât need two for this)
medium-sized plastic bag large enough to fit over bottom end of bottle (diaphragm)
medium-size, thin rubber band

You supply

plastic 2-liter soda bottle with bottom cut off (thoracic cavity)

Tape (optional)

Directions:

1. Insert the balloon through the open bottom of a modified 2-liter soda bottle and up over the neck of the bottle. Pull the end of the balloon over the edges of the neck of the bottle. The balloon is held open by the neck of the bottle.

2. Place the plastic bag over the bottom (open) end of the 2-liter bottle and use the rubber band to hold it in place. This will serve as the diaphragm. To inflate the lung, blow into the balloon just before you fasten the rubber band. You can also wrap tape over the edges of the plastic bag to minimize air leaks

3. Grasp the bottom of the plastic bag and pull it down and push it up. Watch as the "lungs" (the balloon) expand and contract as you do this. The balloon has to change size because the air space between the balloon and bottle must remain constant. (Well, it would if the seal around the plastic bag and bottle were perfect).

You may block the "trachea" (the neck of the bottle) so that the air supply is cut off and watch as nothing happens when the "diaphragm" is pushed in and out.

This model isnât perfect. None of the joints are air tight as they would be in a real thoracic cavity. Pull the âdiaphragm down and watch the lungs expand . If you hold it in place, the lungs will collapse again over time. This is because of leaks and is not how real lungs work. Pushing the diaphragm in and pulling it out over and over does give you an idea of how lungs work. As the diaphragm tightens, contracts (pull down on the plastic bag) the lungs fill with air. As the diaphragm relaxes (push up on the plastic bag) air is expelled from the lungs .

There are several different ways we breath, i.e. expand our thoracic cavity so that our lungs can expand. You have just made a demonstration model of the diaphragm at work. You can also use your rib cage to expand and contract so that you can inhale and exhale. There are muscles between and around your ribcage which you can use to change the size of your thoracic cavity.

This is approximately what your model of a lung will look like.

Answer the questions on the Report Page

Report Page Name

1. Put a hand on your lower ribcage and try moving your ribs out and in. Does air also move in and out?

2. Someone with an upper back or neck injury may not have the options of using diaphragm or ribs to breath. They can learn to use the clavicle and the muscles attached to expand their thoracic cavity a small amount and breathe independently for short periods of time. Put your hand on you clavicle and try to raise and lower just that bone without using your diaphragm or your ribs. It isnât easy but you should be able to get a little air into and out of your lungs this way. How effective do you think this way of breathing is?

3. When you take a really deep breath you use all these muscle groups to help. Take a really deep breath and notice that your ribs expand, your lower abdomen comes out (a sign that the diaphragm has contracted) and your shoulders lift a little (the upper chest and clavicle are working). Now take a relaxed breath. Only your abdomen should go in and out. The movement of your abdomen is a result of the contracting diaphragm pushing on the contents of your âgutâ which forces your abdomen to push out.

Do you breath in or out when your diaphragm contracts?\

4. If a hole were poked in your thoracic wall (the wall of the pop bottle â the hole should be at least the diameter of a pencil)

a. what would happen when you tried to breath? (This is a pneumothorax).

b. Is the space between the balloon and plastic bottle still required to remain constant?

5. Would it be possible to live with a paralyzed diaphragm? Explain your answer.

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Biology 2601A/B Lecture Notes - Lecture 1: Mass Diffusivity, Partial Pressure, Osculum

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