8
Respiratory Responses, Mammalian Diving Response, and Circulation Lab
Introduction
Our respiratory system is a network of organs and tissues that help us breathe. Some of the main organs include our airways, lungs, and blood vessels. It works with the circulatory system to increase blood flow, and oxygen delivery to contracting muscles. Blood vessels in the human body spread from your head, all the way to your toes. Arteries carry the blood away from the heart, while veins carry the blood back to the heart. The mammalian diving response is also known as the diving reflex. It’s when physiological responses when they get immersed underwater that overrides the homeostatic reflexes. This basically means that when they are underwater, they reject the reflex to breathe. In the experiments below we will be observing respiratory responses, circulation, and mammalian diving responses.
Equipment and Materials
- Spirometer
- Pregnancy suit
- Bucket
- Ice or Ice Packs
- Pulse oximeter
- Frogs
- Probe
Pre-Lab Questions
1. Would the resting heart rate of a chihuahua be slower or faster than that of a great dane? Why?
2. Where does the Weddell Seal store most of its oxygen that allows it to dive for longer periods than humans can?
3. Do the lungs expand or compress when diving to deep levels?
4. What happens to circulation with increased vigorous exercise? Where is most of the blood sent through?
5. What is the mammalian diving response? What is bradycardia?
We will be participating in a few activities that will demonstrate the relationship between heart rate and breathing rate as well as the effect of exercise on both heart rate and breathing rate. We will also attempt to replicate the mammalian diving reflex and its physical effects.
Activity 1: Lung Capacity
We will attempt to relate lung capacity to age, gender, and level of activeness. Only using one breath, blow into the spirometer as hard as you can. The spirometer will show you your lung capacity. You will also determine your level of activeness on a scale of 1-5 according to the following classifications:
1- not very active; never work out
2- somewhat active; work out on occasion
3- active; work out about 3 times a week
4- very active; work out almost every day
5- athletic; work out every day
| Name | Gender | Age | Level of activeness | Spirometer number |
| 1 | ||||
| 1 | ||||
| 1 |
Activity 2: Pregnancy Suit Run
In this activity we will look for a relationship between heart rate and breathing rate as intensity of exercise increases. We will also be looking for any differences due to age. Each student will test their heart rate and breathing rate before and after running up two flights of stairs while wearing a pregnancy suit. First take your resting heart rate and breathing rate. Then start on the third floor and jog or walk up the stairs until you get to the fifth floor. Take breathing and heart rate at top of the stairs. Go back to the third floor and wait until your heart rate has lowered almost to resting. Put on the pregnancy suit and walk back up to the fifth floor. Measure heart rate and breathing rate again.
Heart Rate:
| Name | Age | Resting heart rate | Heart rate after first run | heart rate after run with pregnancy suit |
| 1 | ||||
| 1 | ||||
| 1 |
Breathing Rate:
| Name | Age | Resting breathing rate | Breathing rate after first run | Breathing rate after run with pregnancy suit |
| 1 | ||||
| 1 | ||||
| 1 |
Activity 3: Mammalian Diving Response
For this activity we will try to replicate the mammalian diving response. Each student will hold their breath for 30 seconds (or for as long as comfortable) and record heart rate after the 30 seconds. Then submerge your face (up to your temples) into ice water and hold your breath for another 30 seconds. Use a pulse oximeter to record your pulse at the end of the 30 seconds. For those who do not want to submerge the face into ice water, ice packs can be placed on the forehead and neck while holding your breath for 30 seconds.
Resting heart rate:
Heart rate while holding breath in normal conditions:
Heart rate after face submerged in ice water (or ice pack):
Activity 4: Frogs and Muscle Fibers
In this activity we will be observing the muscle fibers at work in a frog. In a confined area, we will chase each frog around the room using a probe or other object and count the number of jumps until the frog becomes fatigued and stops jumping away. Think about the skeletal muscle fiber type that must be involved.
Post-Lab Questions:
1. How much was your lung capacity? Did age, gender, or level of activeness affect your lung capacity? What differences were there between you and your classmates?
2. Did the weight of the pregnancy suit increase or decrease your heart rate or breathing rate? Was it similar to the jog up the stairs without the pregnancy suit?
3. Did you predict your heart rate would increase or decrease when your face was submerged in ice water? What were your findings?
4. What was the average number of jumps a frog did? How long did it take before they became fatigued? What does it have to do with skeletal muscle fiber types? What is the significance of frogs jumping vs toads hopping?
