- Explain how different organ systems relate to one another to maintain homeostasis
Each organ system performs specific functions for the body, and each organ system is typically studied independently. However, the organ systems also work together to help the body maintain homeostasis.
For example, the cardiovascular, urinary, and lymphatic systems all help the body control water balance. The cardiovascular and lymphatic systems transport fluids throughout the body and help sense both solute and water levels and regulate pressure. If the water level gets too high, the urinary system produces more dilute urine (urine with a higher water content) to help eliminate the excess water. If the water level gets too low, more concentrated urine is produced so that water is conserved.
Similarly, the cardiovascular, integumentary (skin and associated structures), respiratory, and muscular systems work together to help the body maintain a stable internal temperature. If body temperature rises, blood vessels in the skin dilate, allowing more blood to flow near the skin’s surface. This allows heat to dissipate through the skin and into the surrounding air. The skin may also produce sweat if the body gets too hot; when the sweat evaporates, it helps to cool the body. Rapid breathing can also help the body eliminate excess heat. Together, these responses to increased body temperature explain why you sweat, pant, and become red in the face when you exercise hard. (Heavy breathing during exercise is also one way the body gets more oxygen to your muscles, and gets rid of the extra carbon dioxide produced by the muscles.)
Conversely, if your body is too cold, blood vessels in the skin contract, and blood flow to the extremities (arms and legs) slows. Muscles contract and relax rapidly, which generates heat to keep you warm. The hair on your skin rises, trapping more air, which is a good insulator, near your skin. These responses to decreased body temperature explain why you shiver, get “goose bumps,” and have cold, pale extremities when you are cold.
Case Study: Fevers
So what happens when you have a fever? Does this mean your body is unable to maintain its homeostasis, in the same way your house will get too hot if your air conditioner is broken?
In extreme cases, a fever can be a medical emergency; but fever is an adaptive physiological response of our body to certain infectious agents. Certain chemicals called pyrogens will trigger your hypothalamus to shift the set point to a higher value. This is more like you programming the thermostat in your house to a higher temperature to save energy on a hot day when you are not going to be home during the day. These pyrogens can come from microorganisms that infect you, or they can be produced by your body cells in response to an infection of some sort.
- As the level of pyrogens increases in your blood, and the set point resets higher, chemoreceptors now stimulating the hypothalamus are responding to ________ as the variable, rather than thermoreceptors responding to body temperature as the variable.
- heart rate
- blood pressure
- The control center is the _________.
- skeletal muscle
- sweat glands
- blood vessels
- Because the set point has been increased, you now feel cold even though you have what would normally be a body temperature within the healthy range. This produces the “chills” you feel when you get a fever. In response, the hypothalumus will work to increase body temperature. Which response will do this?
- The hypothalamus will stimulate sweat glands and dilating blood vessels as effectors to cool off the body.
- The hypothalamus will stimulate skeletal muscles to shiver and constricting blood vessels.
Although the evidence is only indirect, fever is believed to enhance the body’s immune response. The increased temperature may actually impair the replication of infecting bacteria and viruses that are adapted to survive best at your normal homeostatic body temperature range. This can give your immune cells a chance to destroy the microorganisms before they can rapidly multiply and spread in the body. There is also some indirect evidence that increased body temperature slightly modifies several metabolic reactions in ways that also allow the immune system to function more efficiently.
- Once the new higher set point is reached, the thermoreceptors stimulate the _________ as the control center.
- skeletal muscle
- sweat glands
- blood vessels
- In response, the sweat glands and blood vessels (effectors) are stimulated to _________.
- secrete sweat for evaporation and dilate vessels for increased heat loss from blood near the surface of the skin.
- shiver to create heat and constrict vessels to conserve heat by keeping blood away from the surface of the skin.
Unfortunately during some infections, pyrogen levels come in “waves.” This adjusts your temperature set point up and down. When pyrogen levels dip, you get the other part of the fever experience: “the sweats” and feeling flushed. As long as the pyrogen levels continue to increase and decrease you will feel like you are swinging back and forth.
- Once the pyrogen level is reduced because the infection is under control, the ________ (control center) will reset the higher set point to normal.
Your body will continue to swing back and forth between the body’s normal upper and lower temperature limits, but because it is now within your “normal” temperature range, you probably won’t even notice that your body is still at work, maintaining the homoeostasis of this variable.
- Patients often get a fever after an operation. Which of the following would not be a reasonable cause of such a response?
- Tissue trauma from the operation has stimulated body cells to release pyrogens.
- Despite precautions, some bacteria have infected the person during the operation.
- The operation has damaged the thermoreceptors
- Post-operative medications have impacted the immune system, causing the release of pyrogens.
Homeostasis of Ions
Body functions such as regulation of the heartbeat, contraction of muscles, activation of enzymes, and cellular communication require tightly regulated calcium levels. Normally, we get a lot of calcium from our diet. The small intestine absorbs calcium from digested food.
The endocrine system is the control center for regulating blood calcium homeostasis. The parathyroid and thyroid glands contain receptors that respond to levels of calcium in the blood. In this feedback system, blood calcium level is the variable, because it changes in response to the environment. Changes in blood calcium level have the following effects:
- When blood calcium is low, the parathyroid gland secretes parathyroid hormone. This hormone causes effector organs (the kidneys and bones) to respond to increase calcium levels. The kidneys prevent calcium from being excreted in the urine. Osteoclasts in bones reabsorb bone tissue and release calcium.
- When blood calcium levels are high, the thyroid gland releases calcitonin. Calcitonin causes the kidneys to reabsorb less calcium from the filtrate, allowing excess calcium to be removed from the body in urine. Calcitonin also suppresses the formation of active vitamin D in the kidneys; without vitamin D the small intestines don’t absorb as much dietary calcium. Osteoblasts, stimulated by calcitonin, use calcium in the blood to add to bone tissue.
Based on the above description of calcium homeostasis, try to answer these questions:
Calcium imbalance in the blood can lead to disease or even death. Hypocalcemia refers to low blood calcium levels. Signs of hypocalcemia include muscle spasms and heart malfunctions. Hypercalcemia occurs when blood calcium levels are higher than normal. Hypercalcemia can also cause heart malfunction as well as muscle weakness and kidney stones.
What problem(s) is/are associated with calcium homeostasis dysfunction?
- heart disease
- bone disease
Watch this video for another discussion on homeostasis and organ systems:
- Kuelezea jinsi mifumo tofauti ya viungo inahusiana na kila mmoja ili kudumisha homeostasis Kila mfumo wa viungo hufanya kazi maalum kwa mwili, na kila mfumo wa viungo kwa kawaida huchunguzwa kwa kujitegemea. Hata hivyo, mifumo ya viungo pia hufanya kazi pamoja ili kusaidia mwili kudumisha utulivu. Kwa mfano, mfumo wa moyo, mfumo wa mkojo, na mfumo wa limfu husaidia mwili kudhibiti usawa wa maji. Mfumo wa moyo na damu husafirisha umajimaji katika mwili wote na kusaidia kuhisi viwango vya maji na misombo iliyofumwa na kudhibiti shinikizo. Ikiwa kiwango cha maji kinakuwa juu sana, mfumo wa mkojo hutokeza mkojo uliopunguzwa zaidi (mkojo wenye kiasi cha juu cha maji) kusaidia kuondoa maji ya ziada. Ikiwa kiwango cha maji kinapungua sana, mkojo wenye kiasi kikubwa zaidi hutokezwa ili kuhifadhi maji. Vivyo hivyo, mfumo wa moyo, mfumo wa ngozi, mfumo wa kupumua, na mfumo wa misuli hufanya kazi pamoja ili kusaidia mwili udumie joto la ndani. Joto la mwili linapopanda, mishipa ya damu katika ngozi hupanuka, na hivyo kuruhusu damu zaidi itirire karibu na uso wa ngozi. Hilo huruhusu joto litoweke kupitia ngozi na kuingia hewani. Ngozi inaweza pia kutokeza jasho ikiwa mwili unakuwa moto sana; wakati jasho linapoyeyuka, husaidia kupoza mwili. Kupumua kwa haraka pia kunaweza kusaidia mwili kuondoa joto la ziada. Pamoja, majibu hayo kwa ongezeko la joto la mwili hueleza kwa nini unatokwa na jasho, unapumua kwa nguvu, na unakuwa na nyekundu usoni unapofanya mazoezi ya bidii. Kupumua kwa nguvu wakati wa mazoezi ni njia moja ya mwili kupata oksijeni zaidi kwa misuli yako, na kuondoa kaboni dioksidi ya ziada inayotokana na misuli. Kwa upande mwingine, mwili unapokuwa baridi sana, mishipa ya damu katika ngozi hufupika, na mtiririko wa damu kwenye viungo (mikono na miguu) hupungua. Misuli hukata na kupumzika haraka, na hivyo kutokeza joto ili kukuhifadhi. Nywele huinuka na kuingiza hewa karibu na ngozi yako. Majibu hayo kwa kupungua kwa halijoto ya mwili hueleza kwa nini unatikisika, unapata "mwiba wa bata", na kuwa na viungo vya mwili vyenye baridi na vyenye rangi nyeupe unapokuwa na baridi. Utafiti wa kesi: Homa Kwa hiyo ni nini hutokea unapokuwa na homa? Je, hii inamaanisha kwamba mwili wako hauwezi kudumisha homeostasis yake, kwa njia ile ile nyumba yako itawa moto sana ikiwa kiyoyozi chako kimeharibika? Katika hali mbaya, homa inaweza kuwa dharura ya matibabu; lakini homa ni majibu ya kisaikolojia ya mwili wetu kwa vimelea fulani vya kuambukiza. "Kama vile kemikali zinazojulikana kama ""pyrogens"" zinafanya hypothalamus yako kugeuka kwa kiwango cha juu." Hii ni kama programu ya thermostat katika nyumba yako kwa joto la juu ili kuokoa nishati katika siku ya joto wakati wewe si kwenda kuwa nyumbani wakati wa mchana. Pyrogens inaweza kutokea kwa viumbe wadogo ambao huambukiza, au inaweza kuzalishwa na chembe za mwili wako kwa kujibu maambukizi ya aina fulani. Kwa sababu ya kuongezeka kwa kiwango cha pyrogens katika damu, chembe za chemoreceptors zinazosababisha hypothalamus zinafanya kazi kwa joto la mwili. - kiwango cha moyo - shinikizo la damu - kituo cha kudhibiti ni _________. - misuli ya mifupa - tezi za jasho - mishipa ya damu - Kwa sababu kiwango cha kuweka kimekuwa kuongezeka, sasa unahisi baridi hata ingawa una kile ambacho kwa kawaida kitakuwa joto la mwili ndani ya safu ya afya. Hilo hutokeza "kuchoka" unakohisi unapopata homa. Kwa kujibu, hypothalamus itafanya kazi ili kuongeza joto la mwili. Ni jibu gani litakalofanya hivyo? - hypothalamus itasababisha kibofu cha jasho na kupanua mishipa ya damu kama effectors baridi nje ya mwili. - hypothalamus itasababisha misuli ya mifupa kutetemeka na kufupisha mishipa ya damu. Ingawa uthibitisho huo ni wa moja kwa moja tu, inaaminika kwamba homa huongeza uwezo wa mwili wa kujikinga na magonjwa. Kwa sababu ya hali ya joto ya juu, bakteria na virusi vinavyoweza kuishi katika hali ya kawaida ya mwili vinaweza kuzidi kuongezeka. Hii inaweza kutoa chembe za kinga nafasi ya kuharibu viumbe wadogo kabla hawawezi kuzidisha haraka na kuenea katika mwili. Kuna ushahidi wa moja kwa moja kwamba kuongezeka kwa joto la mwili hubadilisha kidogo athari kadhaa za kimetaboliki kwa njia ambazo pia huruhusu mfumo wa kinga kufanya kazi kwa ufanisi zaidi. - Mara baada ya hatua mpya ya juu ya kuweka kufikiwa, thermoreceptors kuchochea _________ kama kituo cha kudhibiti. - misuli ya mifupa - tezi za jasho - mishipa ya damu - Kwa kujibu, tezi za jasho na mishipa ya damu (effectors) huchochewa kwa _________. - kuondoa jasho kwa ajili ya evaporation na kupanua mishipa kwa ajili ya kuongezeka kwa hasara ya joto kutoka kwa damu karibu na uso wa ngozi. - shiver kuunda joto na constrict mishipa ya kuhifadhi joto kwa kuweka damu mbali na uso wa ngozi. Kwa bahati mbaya wakati wa maambukizo fulani, viwango vya pyrogen huja katika "mafuriko". Hii inabadilisha kiwango chako cha joto juu na chini. Wakati viwango vya pyrogen kupungua, wewe kupata sehemu nyingine ya uzoefu wa homa: <unk>the sweats<unk> na hisia flushed. Kwa sababu ya viwango vya pyrogen, unaweza kuwa na wasiwasi juu ya jinsi ya kuendesha gari. Baada ya kiwango cha pyrogen kupungua kwa sababu maambukizi ni chini ya udhibiti, kituo cha udhibiti itarudisha kiwango cha juu cha kuweka kwa kawaida. Mwili wako utaendelea kutikisika mbele na nyuma kati ya kiwango cha juu cha kawaida cha joto na kiwango cha chini cha joto, lakini kwa sababu sasa iko ndani ya kiwango chako cha kawaida cha joto, labda hata hutagundua kwamba mwili wako bado unafanya kazi, kudumisha homeostasis ya tofauti hii. - Mara nyingi wagonjwa hupata homa baada ya upasuaji. Ni ipi kati ya mambo yafuatayo ambayo haingekuwa sababu ya busara ya majibu kama hayo? - Majeraha ya tishu kutokana na upasuaji yamechochea chembe za mwili kutolewa pyrogens. - Licha ya tahadhari, baadhi ya bakteria zimeambukiza mtu wakati wa upasuaji. - Upasuaji umeharibu thermoreceptors - Dawa za baada ya upasuaji zimeathiri mfumo wa kinga, kusababisha kutolewa kwa pyrogens. Homeostasis ya ioni: Kazi za mwili kama vile udhibiti wa mpigo wa moyo, kupunguzwa kwa misuli, uanzishaji wa enzymes, na mawasiliano ya seli zinahitaji viwango vya kalsiamu vilivyowekwa kwa nguvu. Kwa kawaida, tunapata kalsiamu nyingi kutoka kwa chakula chetu. Matumbo madogo huchukua kalsiamu kutoka kwa chakula kilichogandishwa. Mfumo wa endocrine ni kituo cha kudhibiti homeostasis ya kalsiamu ya damu. Tambo ya parathyroid na ya tezi-kibofu zina vipokezi vinavyoitikia viwango vya kalsiamu katika damu. Katika mfumo huu wa kurudia, kiwango cha kalsiamu ya damu ni tofauti, kwa sababu inabadilika kwa kujibu mazingira. Mabadiliko katika kiwango cha kalsiamu ya damu yana athari zifuatazo: - Wakati kalsiamu ya damu ni ya chini, tezi ya parathyroid huondoa homoni ya parathyroid. Hii husababisha viungo vya homoni (figo na mifupa) kujibu kuongeza viwango vya kalsiamu. Figo huzuia kalsiamu isitoke ndani ya mkojo. Osteoclasts katika mifupa hufyonza tena tishu ya mifupa na kutoa kalsiamu. - Wakati viwango vya kalsiamu katika damu ni vya juu, tezi ya tezi-kibofu hutokeza calcitonin. Calcitonin husababisha figo kuondoa kalsiamu kidogo kutoka kwa filtrate, ikiruhusu kalsiamu ya ziada kuondolewa kutoka kwa mwili kwa mkojo. Calcitonin pia huzuia kuundwa kwa vitamini D hai katika figo; bila vitamini D matumbo madogo hayawezi kunyonya kalsiamu nyingi ya chakula. Osteoblasts, zinazosisimuliwa na calcitonin, hutumia kalsiamu katika damu ili kuongeza tishu ya mifupa. Kwa kuzingatia maelezo ya juu ya homeostasis ya kalsiamu, jaribu kujibu maswali haya: Ukosefu wa usawa wa kalsiamu katika damu unaweza kusababisha ugonjwa au hata kifo. Hypokalcemia inahusu viwango vya chini vya kalsiamu katika damu. Dalili za hypocalcemia zinatia ndani mshtuko wa misuli na kasoro za moyo. Hypercalcemia hutokea wakati viwango vya kalsiamu katika damu ni vya juu kuliko kawaida. Hypercalcemia pia yaweza kusababisha kasoro ya utendaji wa moyo na vilevile udhaifu wa misuli na mawe ya figo. Ni tatizo gani (s) ni kuhusishwa na calcium homeostasis dysfunction? - ugonjwa wa moyo - ugonjwa wa mifupa Angalia video hii kwa majadiliano mengine juu ya homeostasis na mifumo ya viungo: