Objective 7: Analyze factors that can affect cellular activities

To be honest, I'm not quite sure what the exact answer to this objective might be. It is such a broad objective that it could probably go in any direction. The body is an amazing, complex system! It consists of quite a number of unique systems, organs, tissues, hormones, cells and process that work together to achieve and maintain homeostasis. If even one of these systems, or even tissues for that matter, malfunctions in the slightest way our body could be thrown out of homeostasis. There are countless factors that could affect the body negatively, which could affect the body and its cellular activites. Since there is seems to be no right or wrong answer in an objective as broad as this one, I decided to list some of the factors that we've learned in our class that could throw off the bodies homeostasis. Here goes nothing!

Dehydration

Excess water in the body

Temperature

Hormonal Imbalances

Medications

Bacterial or Viral Infections

Auto-immune diseases

Hypersecretion of a hormone

Hyposecretion of a hormone

Edema

Lymphedema

High blood pressure

Organ failure

Blockage of an artery or vein

Low blood pressure

Respiratory Alkalosis/ Acidosis

Metabolic Alkalosis/ Acidosis

Carbon monoxide poisoning

Hyperventilation

Malnutrition

Stress

Cancers

Tachycardia

Bradycardia

Hormonal Imbalances

Obesity

Sexually Transmitted Diseases

Changes in pH

Urinary Retention

Changes in Osmolarity

The list of factors that can affect cellular activities of the body could go on forever. I decided to list just a few of the topics that we have covered in class that can cause the body fall out of homeostasis. I could go on for days just listing factors, but I'm sure I've hit a few key points. The body has amazing systems and process that can detect fators such as these and respond to them in their own unique way to bring the body back to homeostasis.



Objective 67: Contrast volume and electrolyte content in inter- and extracellular fluid compartments

With the help of some excellent diagrams, this objective was a breeze. Did I stress that diagrams are extremely helpful in learning a majority of these concepts? I obtained these photos and slides from the PowerPoint lecture outlines available for our class and included them. Although, I did refer to my textbook for some more information and that helped out a great deal. The first photo that I've included can be found in chapter 25 page 868 and the fourth photo can be found in chapter 25 page 869. The first photo breaks down the major fluid compartments of the body, and it is plain to see that intracellular fluid makes up the majority of it. That makes sense, cells need fluids to perform their functions. Extracellular fluid is composed of two things, interstitial fluid and plasma. ICF is 25 L of our bodies total water, while ECF is only 15 L of our bodies total water (40 L all together). The last chart is very helpful because it shows the total solute concentration that each electrolyte occupies in ICF, ECF, and blood plasma.

Objective 20: Describe the structure, functions, life cycle, production or erythrocytes and leukocytes

I'm pretty positive that I could have included this objective with another previous blood objective, but I thought this one sounded harder than it actually was (go figure, I seemed to have done that with a lot of them). The blood and cardiovascular system are the two systems that I am most familiar with (and are probably some of the more easier systems of the body), so I didn't have my head spinning half of the time trying to grasp the concepts. The textbook was my main aid in trying to figure out the structure, function, life cycle, and production of the erythrocytes and leukocytes. I found this chart in chapter 16 page 562 that summarizes all of this information in one place. I've never been so grateful for a chart in my life. The text does describe the erythrocytes and leukocytes in detail, but c'mon who doesn't love a very informative chart? The chart not only provided me with the information I was looking for, it also shows you a picture of a erythrocyte and pictures of all the leukocytes. A chart can't get any better than that!

Objective 44, 45, 46, 47: Respiratory system

Objective 44: Locate and identify the functions of each respiratory system structure
Objective 45: Characterize the neuronal network that controls respiration
Objective 46: Relate breathing to cellular respiration
Objective 47: Decide how arterial carbon dioxide concentrations affect ventilation

Wow, I'm surprised that I am able to gather that many objectives in one blog. That really shows you how similar all of these processes are and how our body works together to accomplish tasks. Our textbook's website (MyA&P) provides an excellent Interactive physiology website that gives in-deph animated tutorials. On this website, I went under the respiratory system tab and reviewed the anatomy review and control of respiration. The videos remind me of a mini animated powerpoint, but it is ten time better than that because the site allows you to interact with it on certain topics. Since i'm a visual learner and I prefer animated videos showing me the topic, I am more than thrilled that this site had what I was looking for.

The anatomy review video was amazing in showing me the location and informing me of the function of the respiratory system. There are certain points in the video where I was able to click my mouse on certain structures of the respiratory system and it would zoom in, giving me a closer view of the structural make-up. Interacting with this visual lesson was a big help, and gave me a little more insight on the respiratory system than just reading alone. The control of respiration video was beneficial in helping me understand the neuronal network that controls respiration and how carbon dioxide affects ventilation. To be honest, I didn't know that there were inspiratory neurons in the medulla. I always knew, from previous classes, that breathing was controlled near the brain but I was never quite clear how. This video also broken down the effect CO2 on ventilation at the end with a flow chart. So, it goes like this. An increase of PCO2 in the blood cause a decrease in pH, which stimulates the peripheal chemoreceptors to send nerve impulses to the respiratory center. This causes a decrease in pH in the brain, which stimulates central chemoreceptors to send nerve impulses to the respiratory center. The respiratory center then stimulates the respiratory muscles, which increase the ventilation and helps the blood get back to normal levels.

Trying to relate breathing to cellular respiration was another one of my big challenges. It seems no matter where I looked for the information, there was nothing on how the two were similar. I finally found one site that made the topic less foggy for me. So, basically breathing is related to cellular respiration because it provides the mechanism for gas exchange. Cellular respiration requires the intake of oxygen to perform. Cellular respiration breaks down energy-rich molecules to harvest ATP, and then ATP is used for basically all the work that the cells perform. While I was trying to find the answer to what cellular respiration really is, I came across this Cellular Respiration video that relates cellular respiration to examples in life. It was extremely helpful for me.

Objective 68 & 70: Chemical buffer system

Objective 68: Recognize how chemical buffers interact to protect the body against lethal changes of pH
Objective 70: Recognize how the lungs and kidneys interact to protect the body against lethal changes of pH

Wow, if only you know how long it actually took me to figure this objective out. I put it off as long as I could because I try to stay as far away from anything remotely chemistry related as possible. I finally decided to be brave and take a stab at it, and I realized that the lecture outline and textbook gave some quite handy information on the chemical buffer system. Mind you, this topic is still very confusing for me. Still, the lecture outline and book helped me a great deal in trying to sort this information out in my head. Are you ready? Here's what I learned from the textbooks information.

Our body chemical buffer is a system of one or more compounds that act to resist changes in pH when a strong acid or base is added. They do this by either binding to hydrogen whenever the pH drops or releasing hydrogen whenever the pH rises. The chemical buffer system is composed of bicarbonate, phosphate, and protein buffer systems. These buffer systems are so closely related which allows any drifts in pH to be resisted by the entire buffer system. The bicarbonate buffer system buffers both ICF and ECF, but it is the only important ECF buffer. The phosphate buffer system is a very effecient buffer in urine and in ICF. Proteins in plasma and cells are the body's most powerful source of buffers.

The kidneys and lungs play an important part in protecting the body against lethal changes of pH as well. Chemical buffers cannot remove excess acids or bases from the body, and thats where the kidneys and lungs come into play. I kind of see them as the football players on the bench waiting for their turn to get into the game. Kidneys adjust bicarbonates, eliminate fixed metabolic acids (phosphoric, uric, lactic acids, and ketones), and prevent metabolic acidosis. The lungs eliminate carbonic acid by expelling carbon dioxide. It is amazing how different systems of our body work together to maintain homeostasis.

I know I'm teaching the topic again to you it seems, but being able to write out a summary of how the chemical buffer system is important really does help me grasp the information better. I guess since i'm writing it out, it's sticks easier to my brain.

Objective 69: Asses how water excess and dehydration affect kidney function

This seemed like a very easy objective when I started this blog, but after searching for the answer I realized that I couldn't really pinpoint the exact answer I was looking for. I started off searcing the internet, but it just ended up giving me a bunch of crazy answers that had nothing to do with this objective. So much for trying to find something to reinforce my understanding. After my unsuccessful search on the internet, I referred back to the handy textbook and found just what I was looking for in Chapter 25 page 873. What was I thinking trying to go somewhere else? haha. What I learned from the urinary chapter is that the kidney is the key organ to water homeostasis. The kidneys are able to retain or eliminate water, to regulate total body water it's concentration. When the body is dehydrated, there is extracellular fluid loss and insensible water loss for whatever reason. Dehydration causes water to be lost from ECF and inadequate blood volume to maintain normal circulation. When the body has excess water, the ECF osmolality drops and ADH release is inhibited. Then less water is reabsorbed and excess water is flused from the body in urine. This excess water causes the ECF fluid to be diluted and can leads to severe metabolic disturbances.

Objective 13: Name hormones of the gonads and give their functions

Being able to name the hormones of the gonads and state their functions seemed like a pretty easy task, but I was left confused after reading the textbook. So I'll start with the common knowledge. The male and female gonads (sex organs) produce steriod hormones, like the ones produced by adrenal cortical cells. The female gonads consist of the ovaries, and the most important hormones they secrete are estrogens and progesterone. The male gonads consist of the testes (located in the scrotum), and the most important hormones that they secrete are testosterone. Sounds simple enough, right? The textbook was a great help in figuring out this information but instead of referring to the reproductive chapter, I referred to the endocrine chapter. But where does the gonadotrophins come into place? Since the gonadotrophins had the word gonad in them, I was pretty sure that they had to be part of the hormones that the gonads secrete. Wrong! The gonadotrophins actually regulate the release of the gonadal hormones. Im glad that the textbook was able to clear that up.

Functions:

Estrogens: responsible for maturation of the reproductive organs and appearance of the secondary sex characteristics of females at puberty

Progesterone: stimulate the growth of a cushion lining in the uterus where the fertilized egg can grow, promotes breast development and cyclic changes in the uterine mucosa

Testosterone: initiates the maturation of the male reproductive organs and the appearance of secondary sex characteristics and sex drive