DQ1
1) J.W Re: Topic 5 DQ 1
Professor and class,
Homeostasis is important to the organism, it keeps the state of the internal conditions of the organism stable. Two forms of feedback help in this process, they are negative and positive feedback loops. These loops help to control the body’s temperature, pressure, blood and tissue chemistry. The control center for the feedback loops are found in the brain. (BiologyDictionary, 2018) When disruptions occur the brain sends messages to the body’s organs alerting them to return to the normal range. Negative feedback loops act to stop or reverse processes which go outside the body’s normal range achieving equilibrium, whereas positive feedback intensifies the change in the body’s physiological condition thus pushing it out of range. (BiologyDictionary, 2018) Negative feedback occurs more frequently in the body when disease interrupts its mechanisms bringing it back to equilibrium. Positive feedback amplifies disruptions and thus may lead to even more problems, even death. Positive feedback usually needs an external interruption to occur for it to stop whereas negative feedback ends on its own when stability is achieved. Negative feedback resists change whereas positive feedback supports it and thus may lead to instability.
Some examples of negative feedback loops are the regulation of blood pressure, blood sugar, blood gases, blood pH, fluid balance, and erythropoiesis (red blood cell production). In terms of thermoregulation, when it is very hot, the body activates the sympathetic nervous system to cause sweat glands to produce sweat which evaporates and thus cools down the skin and blood vessels. When it is cold outside, the body shivers creating vasoconstriction which reduces blood flow to the limbs and redirects it to the veins and arteries in the blood transferring heat and creating warmth for the body. Some examples of positive feedback loops are blood clotting and the release of hormones via the endocrine system. This system releases oxytocin which increases contractions during childbirth to help to push the baby out. Blood clotting occurs as a series of events via the positive feedback loop when the body tissues are damaged in order to form clots and stop bleeding.
2) A.W Re: Topic 5 DQ 1
Negative feedback loops control most process in our bodies. These are done to help maintain homeostasis or a specificlevel that the body needs to be at in order to function properly. Temperature and blood pH levels are examples things that need to be maintained and stay at a specific range or the body will shut down. If acid builds up and can’t be lowered you can become confused, tired, get a headache, increased heart rate, and have fruity breath (Allen, 2018). If this happens a negative feedback will occur that will cause the body to lower the pH in the blood. Negative feedback loops are so good at this since it reacts to a scale and if it getstoo high or too low the body does what it needs to bring it back to the comfort range (Khan Academy, 2021). It takes less energy to react and fix something then to constantly maintain the system. If the system needs a push to complete a positive feedback loop can be started. This happens during childbirth when the baby’s head starts to push on the cervix. This startsa reaction of hormones that help with contractions that don’t stop till the baby is out (Khan Academy, 2021).
Allen, Suzanne. 2018. Healthline. Acidosis. Retrieved on 2/17/2021 from https://www.healthline.com/health/acidosis
Khan Academy. 2021. Homeostasis. Retrieved on 2/17/2021 from https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-body-structure-and-homeostasis/a/homeostasis
3) T. M. Re: Topic 5 DQ 1
Homeostasis is when the body is kept at a stable place by reacting to negative and positive loops. Negative feedback Is a process where the body will respond to a variable to bring it back to homeostasis. The body will reverse the change. Body temperature is a good example. When your body goes up in temperature the body begins to sweat to cool you off or you may enter a room that is air-conditioned and the body will begin to shake, you get chills and this reaction causes the muscles to react and this makes your body warm again. These actions will bring the body back to homeostasis with the negative loop system,
With the positive feedback loop, positive feedback will trigger another reaction until reaction. A positive feedback example is with childbirth. When a woman is in labor she has contractions to help dilate her uterus. With every contraction, oxytocin is released bringing on more contractions causing dilation, and eventually birth after birth the body returns to a homeostatic state. Sometimes other negative feedback will react to positive feedback.
Reference
Anatomy and Physiology. ( 2013) , May 18. Homeostasis: positive/ negative feedback mechanism. Homeostasis: positive/ negative feedback mechanisms : Anatomy & Physiology (anatomyandphysiologyi.com)
4)J.W Re: Topic 5 DQ 1
Hello Marie,
The endocrine system plays a very significant role maintaining homeostasis in the body. It uses the feedback loop system in order to function effectively. This system which is composed of glands produce hormones that control our bodily functions. “The feedback loop acts like a “thermostat” which responds to changes in the temperature and informs the furnace when to switch it on or off.” (Thyroid Advisor, 2019) The hypothalamus acts like the thermostat of feedback systems and the endocrine system acts like the air conditioner or heater. Hormones are either released or stop being produced in response to messages sent by the hypothalamus. When a signal is received, a hormonal response takes place and a reaction occurs. Glands which do not constantly secrete hormones rely on the presence or absence of hormones in the blood to turn their secretions on or off. If there is not enough secretion in the blood, the gland makes more, increasing blood hormone level. If there is too much hormone, the gland stops making it thus leading to lower blood hormone levels. The feedback system is the basis for the mechanism of the endocrine system.
Kindly,
References:
Thyroid Advisor (2019, April 9) What You Need To Know About The Thyroid Feedback Loop. Retrieved from https://thyroidadvisor.com/know-thyroid-feedback-loop/#:~:text=Feedback%20loops%20refer%20to%20the%20manner%20that%20the,are%20responses%20that%20trigger%20other%20processes%20and%20activities.
Tulane University (n.d) E. Hormone. A Gateway To Environmental Signaling. Endocrine System: Feedback Loops. Retrieved from http://e.hormone.tulane.edu/learning/feedback-loops.html
DQ2
1) A.W Re: Topic 5 DQ 2
Osmoregulation is the process that allows us to maintain the level of fluids in our bodies. We need proper balance of fluids for our cells and organs to work properly. Water pressure goes from high to low or least amount of resistance. To change these levels the body can send out hormones that regulate pressure to help dictate where the fluid needs to go in order to maintain homeostasis. Another process that mammals use to maintain fluid levels is changing the size of the arteries (NCBI, 2021). By constricting the artery, you increase the pressure and by dilating them you decrease the pressure. This changes the flow and helps balance out the fluids.
2) J.W Topic 5 DQ 2
Professor and class,
Osmoregulation is very important to the survival of living things, and mammals have specially designed systems in place to make sure that this process works efficiently to maintain homeostasis within the body. Osmoregulation is the process by which the body regulates the osmotic pressure of fluids. It does this by keeping the water level constant (cells remain isotonic) and thus maintaining homeostasis. (Homeostasis in Humans, n.d) This process maintains a proper balance of electrolytes and non-electrolytes (solutes which dissociate in to ions when dissolved in water and those that do not dissociate when dissolved, respectively) within the cells, tissues and in interstitial fluid by diffusion of water or solutes, and osmosis. Water movement due to osmotic pressure across membranes alter the fluid compartment (blood plasma, cytosol, interstitial fluid) within the body which influences medical issues such as blood pressure. Water balance is regulated by urination, defecation, sweating and respiration. (Boundless, 2020) Within the body, the tissues and organs are immersed in fluid which helps to maintain homeostasis. Some solutes within the body which are involved in osmoregulation are salts and sugars. Osmoregulation maintains salt and water balance. Mammals regulate their osmotic pressure by maintaining normal levels of concentrations of electrolytes found in plasma, extracellular and intracellular fluid. When disease or trauma affects the body’s ability to carry out the process of osmoregulation many issues may arise such as the accumulation of toxic waste or water which may cause edema (swelling). When a person’s kidneys are failing, the body’s ability to regulate fluid balance and excrete toxic waste are affected, thus their osmoregulation and homeostasis become inefficient leading to other medical problems.
Kindly,
References:
Boundless. (2020, August 15) Biology LibreTexts. Introduction to Osmoregulation. Retrieved from https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/41%3A_Osmotic_Regulation_and_the_Excretory_System/41.1%3A_Osmoregulation_and_Osmotic_Balance/41.1A%3A_Introduction_to_Osmoregulation
Homeostasis in Humans (n.d) Homeostasis. Blood Water Homeostasis or Osmoregulation. Retrieved from https://homeostasisinhumans.weebly.com/osmoregulation.html
3) T. M Re: Topic 5 DQ 2
Osmoregulation has to do with the regulation of the internal environment and the external environment via osmosis which is the process of molecules of a solvent being passed thru cell wall, due to a high or low solvent. In humans, osmoregulation takes place in the kidneys as the kidneys filter the blood. The blood gets filter by entering the glomerulus capsule and depending on the environment water is either taken from the blood and into the urine or it stays in the blood. Sinals are sent to the brain to send or withhold the ADH, antidiuretic hormone.
Two strategies used are Osmoconformers and Osmoregulators. With osmocomforters processors that are passive or active are used to match their internal osmolarity to that of the environment. ( Helmenstine 2018) With osmoregulators control internal osmotic pressure most mammals utilize this strategy. ( Helmenstine 2018)
Different examp;es of osmoregulation can be found from plants tp mammals. Ultimately this process is needed in homeostasis.
Reference
Helmenstine Ph.D, A.(2018, May 2). Osmoregulation Definition and Explanation What You Need to Know About Osmoregulation. https://www.thoughtco.com/osmoregulation-definition-and-explanation-4125135 .
4) Re: Topic 5 DQ 2
Hello Marie,
Osmoreceptors are very important to our body’s regulation of fluid control, as you stated. They are found mainly in the hypothalamus but also in the liver-portal system, gastrointestinal tract and the oropharynx. They monitor the concentration of solutes in the blood and in the case of dehydration where there is water loss and thus an abnormal increase of solutes, these receptors are triggered. They stimulate the release of vasopressin from the pituitary gland and acts on the kidneys to reduce water loss. They respond to dehydration on a cellular level by responding to changes to osmolality as fluid leaves the cells through osmosis. These receptors are very important because they sound the alarm to the rest of the body that its water levels have dropped, thus kickstarting its defense mechanisms to restore homeostasis before extreme dehydration occurs, which may have detrimental consequences to the individual’s well-being.
Kindly,
Jerilyn Walters
References:
Wilkinson, K. (2019, July 23) Career Smart Learning. Osmoreceptors: Your Body’s Dehydration Defenders. Retrieved from https://careersmart.com/osmoreceptors-your-bodys-dehydration-defenders/
Youngson, R. M. (2004, 2005) Collins Dictionary of Medicine. Osmoreceptors. Retrieved from https://medical-dictionary.thefreedictionary.com/osmoreceptors
