Lab Report: Tissues, Organs, and Organ Systems
Activity A: Homeostasis exercise
This exercise comprised recording of changes in temperature, heart rate and respiration rate following an exercise. The exercise involved various activities including vigorous jogging and push-ups, the activities lasting for a period of 10 minutes. Temperature (in degrees Celsius) was recorded using an ear thermometer, while heartbeats and inhalations were counted for a minute for each interval. The recordings for the three aspects were done before the exercise and at five-minute intervals after ten minutes following the end of the exercise. A stopwatch was used to keep time of the one-minute durations when the recordings were done. The data for the measurements were recorded in the table below and a graph of the changes for each variable as in figure 1:
Table 1: Results of Homeostasis Exercise
|Before Exercise||After Exercise|
|0 min||10 min||15 min||20 min||25 min||30 min|
|Body temperature (degrees Celsius)||36.7||37.9||37.5||37.2||37||36.9|
|Heart Beats per minute
|Respiration rate (inhalations per minute)||12||16||14||12||12||12|
Fig. 1: Changes in Body Temperature, Heart rate and Respiration rate after exercise
- Changes observed in the pre-exercise and post-exercise stages. Before exercise, the subject’s temperature was 36.7°C, which rose and remained above the baseline levels even after 30 minutes after completing the exercise. Ten minutes after the exercise, the subject’s temperature was 37.9°C, which declined gradually in subsequent measurements up to 36.9°C in the last measurement. Such maintenance of higher shell temperature levels (temperatures on skin surfaces) even after the exercise ends have been reported in other studies (e.g. Lim, Bryne, & Lee, 2008), and are indicated to be influenced by aspects such as the temperatures in the environment (Lim et al., 2008). On the contrary, the heart rate and respiratory rate returned to their baseline levels by the 20-minute measurement interval after the exercise. Other changes observed after the exercise were sweating and shortness of breath. These changes, however, resolved as the time after the exercise lengthened.
- Time it took to return to pre-exercise levels. Temperature did not return to the pre-exercise level within the time the measurements were supposed to be carried (30 minutes). However, heart rate and respiratory rates returned to the respective baseline levels by the measurement interval at 20 minutes after the exercise.
- I expected these changes since they have been noted in other studies (e.g. Du et al., 2005; Lim et al., 2008). However, I was not aware that changes in temperature would take long to return to their baseline due to the perception that humans, being among animals that maintain a temperature homeostasis despite the environment, would tend to maintain the temperature levels within a constant level. However, a note in Lim et al. (2008) study of two types of temperatures, the core temperatures regulated by the brain, and the shell temperature that is influenced by environmental aspects helped clarify the observations.
- Differences in our results with other results I could access related to higher values in the recordings for temperature, heart rate and respiration rate after exercise for the other group. Such results may be explained by aspects such as intensity of the exercise involved in, and physiological differences among the subjects whose data were recorded (Du et al., 2005; Lim et al., 2008).
- The systems that were involved to enable the subject perform the exercise included the cardiovascular, respiratory, endocrine and nervous systems. Cardiovascular system comprises the heart and the blood vessels. The respiratory system comprises the lungs and the airways. The nervous system comprises the brain and the neurons. The endocrine system comprises the hormones.
- The endocrine system served as a signal to the body that energy was needed for the exercise, with the message being transmitted via the nervous system to the brain. The brain interpretation of the signal resulted in messages sent to the respiratory and circulatory systems to increase the respiratory rate and heart rate respectively. Increased respiratory rate was needed to compensate for higher oxygen demand, which, in turn, needed the higher heart rate for the delivery to respective tissues and cells that facilitated the activities.
- Such changes were necessary because the subject during physical activity needed higher levels of energy as compared to energy required during resting state. To provide such energy, the changes were necessary.
- Lessons Learned. The body has various mechanisms to maintain its functions within physiological ranges. Departure from such physiological ranges leads to activation of such mechanisms to restore it to its physiological ranges.
Activity B: Skin
- Requires slides
- Similarities between skin and hide. The similarities between the skin and hide arise in the types of tissue present. They have cells organized into the epidermis, dermis, and fat cells from where hair follicles emanate (Sherwood, 2013).
- Requires slides
- Requires slides
- Requires slides
- Mouth lining scrapings for DNA analysis. Use of mouth scrapings for DNA analysis is preferred due to various aspects. These include ease of collection, non-invasive as compared to samples such as blood, and that they do not require preservatives, which can help to maintain evidence in a good form for longer periods.
- Differences in epidermal layer of humans and dogs and cats. The differences include thickness, with human epidermis cells being thicker compared to those of dogs and cats. The epidermis also have different rates of replacement with Canine’s being replaced at a rate of 20 days while humans’ is replaced at a rate of 28 days. The other difference concerns hair, where in humans it grows as a solitary unit continuously, while in canines it grows in bundles in cycles.
Activity C: Nerve Cells
- The purpose of the nerve cells is to transmit nerve impulses from the receptor sites (such as skin, eyes, nose [sensory organs] and internal receptor sites) to the brain for interpretation and back to the sites where action is required.
- The function of nerve cells differs from that of the endocrine system in that the endocrine system serves as a signaling system, whereby the changes in the body trigger the system to produce hormones, which then bind receptors to facilitate a specific action. The action of the endocrine system is controlled by the hypothalamus (a part of the brain), which responds to stresses in the body by facilitating endocrine glands to secrete hormones into the blood system for transport to their site of action (Sherwood, 2013). On the contrary, the nerve impulses are in the form of electrical potentials, rather than hormones, which are transmitted via the nerve cells through changes in the membrane potentials of the nerve cells (Sherwood, 2013).
- Where most nerve tissue is located. Nerve tissue is found in the brain, spinal cord and peripheral nerve sites (i.e. nerves that extend from the brain and spinal cord to other parts of the body).
- Where least likely to find nerve tissue. The cartilage does not contain any nervous tissue since it is comprised only of chondrocytes (Sherwood, 2013). The reason for the absence of nervous system is because cartilage is not involved in transduction of impulses but serves in bone joints to ensure smooth movement.
Activity D: Muscles and Bones
a). Types of Muscles. The three types of muscle are smooth muscle, cardiac muscle and skeletal muscle. Skeletal muscle and cardiac muscle are comprised of striated tissue, which is comprised of long elongated fibers (Sherwood, 2013). Smooth muscle is comprised of un-striated tissue. The skeletal muscles are found skeleton surfaces involved in movement (Sherwood, 2013). Their contraction results to movement. The cardiac muscles are found in the heart and are involved in the contraction and relaxation of the heart to facilitate pumping of blood (Sherwood, 2013). Smooth muscles are found in vascular sites (e.g. blood vessels, and digestive system). Their contraction enables flow of substances along such vascular sites (Sherwood, 2013).
b). Requires slides
c.) i) Beef roast – Skeletal Muscle
- ii) Beef heart – Cardiac muscle
iii) Beef tongue – Skeletal muscle
- iv) Tripe – Smooth muscle
- v) Chicken drumstick – skeletal muscle
Vi) Fish fillet – Skeletal muscle
- d) Why muscle cells vary in cell makeup. Muscle cells vary in cell makeup due to their varying functions. For example, the skeletal muscle facilitate energy-intensive activities that require involvement of somatic (‘voluntary’) nervous system for action. The smooth muscles primarily are under the influence of the autonomic “involuntary” nervous system and not involved in energy-intensive activities. Such differences in function account for the differences observed in the type of muscle.
- e) Location of beef ‘Knucklebones’ in a cows body. The cows knuckle bones are found below the knees on the feet. In humans, such bones would be synonymous to the ulna-radius bones that are found on the forearm.
- f) Functions of various structures found in the bone.
Du, N., Bai, S., Oguri, K., Kato, Y., Matsumoto, I., Kawase, H., & Matsuoka, T. (2005). Heart rate recovery after exercise and neural regulation of heart rate variability in 30-40 year old female marathon runners. Journal of Sports Science and Medicine, 4, 9-17. Retrieved from http://www.jssm.org/vol4/n1/2/v4n1-2pdf.pdf
Lim, C. L., Bryne, C., & Lee, J. K. W. (2008). Human thermoregulation and measurement of body temperature in exercise and clinical settings. Annals, Academy of Medicine Singapore, 37(4), 347-353. Retrieved from http://www.annals.edu.sg/PDF/37VolNo4Apr2008/V37N4p347.pdf
Sherwood, L. (2013). Human physiology: From cells to systems (8th ed.). Belmont, CA: Cengage Learning.
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