Tsav unit - yog dab tsi?

Tsav los yog lub cev muaj zog tsev yog ib pab pawg neeg ntawm fibers uas yog innervated los ntawm ib tug motoneuron. Tus nqi ntawm cov fibers teej tug mus rau tib lub tsev, tej zaum yuav txawv nyob ntawm seb cov kev ua ntawm cov nqaij. Tus me zog nws muab, tus me tus lub cev muaj zog tsev thiab tsawg rau siab no yog tsim nyog rau nws cov excitation.

Tsav units: lawv cais.

Nyob rau hauv txoj kev tshawb no ntawm no lub npe yog ib qho tseem ceeb lub sij hawm ntawd. Yog cov kev uas ib lub tsev muaj peev xwm yuav yus. Physiology raws li ib tug science, qhia ob no:

• ceev yuav txo tau nyob rau hauv cov lus teb rau ib tug tuav lub teeb liab;
• qaug zog ceev.

Raws li, nyob rau lub hauv paus ntawm tej cim no, peb hom kev lub cev muaj zog units peev xwm yuav txawv.

1. Maj mam, tsis tiring. Lawv lub cev muaj zog neurons muaj ib tug ntau ntawm myoglobin, uas muaj ib tug high affinity rau oxygen. Nqaij uas yog nyob rau hauv ib tug ntau ntawm qeeb lub cev muaj zog neurons yog hu ua liab vim hais tias ntawm lawv cov xim. Lawv yuav tsum tau kom muaj tib neeg hwj tau lub cev thiab kom nws nyob rau hauv tshuav nyiaj li cas.
2. Ceev, log tsheb. Cov nqaij yog tau ua ib tug loj tus naj npawb ntawm txiav nyob rau hauv ib tug luv luv lub sij hawm ntawm lub sij hawm. Fibers lawv muaj ib tug ntau ntawm lub zog cov ntaub ntawv uas los ntawm uas los ntawm txoj kev oxidative ntsev yuav tau molecules ntawm ATP.
3. Fast, resistant rau qaug zog. Cov fibers muaj ob peb mitochondria, thiab ATP tsim los ntawm cleavage ntawm zib molecules. Cov nqaij yog hu ua dawb vim hais tias lawv tsis muaj myoglobin.

Cov units ntawm cov thawj hom

Cov propulsion chav tsev ntawm tus thawj hom los sis qeeb neutomlyaemaya, tshwm sim feem ntau nyob rau hauv loj nqaij. Tej motoneurons muaj ib tug uas tsis muaj excitation pib thiab cov kev ceev ntawm paj lam ua. Central paj cell outgrowth nyob rau hauv nws cov davhlau ya nyob twg feem yog branched thiab me me fiber innervates pab pawg neeg. Tus zaus ntawm ntswg tuaj mus rau lub qeeb lub cev muaj zog rau lwm - los ntawm rau mus rau kaum pulses ib ob. Motoneuron yuav txhawb xws li ib tug lub suab nyob rau hauv ib ob peb kaum feeb.

Lub hwj chim thiab ceev kom txhob muaj lub cev muaj zog units ntawm cov thawj hom thiab ib tug ib nrab lub sij hawm tsawg tshaj li lwm hom ntawm lub cev muaj zog units. Yog vim li cas rau qhov no - tsis muaj tus nqi ntawm ATP thiab qeeb outputs ntawm calcium ions nyob rau hauv lub txheej cell daim nyias nyias rau cov thwj toob rau troponin.

Cov units ntawm lub thib ob hom

Cov propulsion unit ntawm no hom muaj ib tug loj lub cev muaj zog-neurone nrog ib tug tuab thiab ntev axons uas innervate ib tug loj pawg ntawm nqaij fibers. Cov paj hlwb muaj lub siab tshaj plaws pib ntawm excitation thiab cov kev kub ceev ntawm paj impulses.

Thaum lub siab tshaj plaws voltage ntawm nqaij, paj mem tes zaus yuav ua tau mus tsib caug vib nas this. Tab sis motoneuron yog tsis muaj peev xwm kom muaj ib tug ntev-lub sij hawm conduction tshaj tawm li ntawd, ceev ceev nkees. Lub zog thiab tus nqi uas yuav txo tau nyob rau hauv cov nqaij fibers ntawm lub thib ob hom siab tshaj yav dhau los ib tug, txij li thaum tus nqi ntawm cov myofibrils therein ntau. Lub fibers muaj ntau enzymes uas ua txhaum down zib tab sis tsawg mitochondrial protein myoglobin thiab cov hlab ntsha.

Chav ntawm peb hom

Cov propulsion unit ntawm peb hom yog ceev, tab sis resistant rau qaug zog cov nqaij fibers. Raws li nws tus yam ntxwv nws yuav tsum coj ib tug intermediate nqi nruab nrab ntawm cov thawj hom thiab ob lub cev muaj zog units. Cov nqaij fibers rau cov nqaij ntshiv muaj zog, ceev ceev thiab tawv. Zus tau tej cov zog nws yuav siv ob qho tib si aerobic thiab co txoj kev.

Qhov ratio ntawm ceev ceev thiab qeeb fibers yog txhob kaw determined thiab yuav sib txawv nyob rau hauv cov neeg sib txawv. Uas yog vim li cas ib tug neeg yog qhov zoo ntawm nyob deb khiav, ib tug neeg yooj yim overcomes lub puas meters khiav, thiab ib tug neeg ntau suited weightlifting.

Reflex mus rau lub nro thiab lub cev muaj zog neuron pas dej ua ke

Thaum ncab txhua leeg fiber qeeb tus thawj teb. Lawv neurons tsim ntswg mus txog kaum pulses ib ob. Yog hais tias cov nqaij mus txuas ntxiv mus ncab, cov generated mem tes zaus yuav nce mus rau tsib caug. Qhov no yuav ua rau ib tug yuav txo tau ntawm lub cev muaj zog units ntawm peb hom, thiab ua rau kom mob zog tenfold. Thaum ntxiv ncab txuas lub cev muaj zog fibers ntawm lub thib ob hom. Qhov no yuav muab lub hwj chim nqaij rov qab nyob rau hauv plaub los yog tsib lub sij hawm.

Cov propulsion chav tsev ntawm nqaij yog tswj los ntawm lub cev muaj zog neurons. Ib co ntawm cov hlab hlwb uas ua tau ib leeg, hu ua lub cev muaj zog neuron pas dej ua ke. Nyob rau hauv ib pas dej ua ke yuav ua tau ib txhij los ntawm ntau neurons, zoo thiab ntau qhia, lub cev muaj zog units. Vim li no, cov hlob thiab cov nqaij fibers muaj nyob rau hauv cov hauj lwm uas ib txhij thiab rau cov neeg uas nws yuav tsub kom lub nro thiab cov kev ceev ntawm paj impulses.

"Lub hauv paus ntsiab lus ntawm cov nqi"

Cov propulsion chav tsev ntawm nqaij, nyob ntawm seb nws hom, yog txo tsuas yog thaum muaj tej yam lub chaw pib load. Tus txheej txheem excitation stereotyped lub cev muaj zog units: thawj txo fine lub cev muaj zog neurons, paj impulses ces maj mam tau mus rau loj loj. Qhov no qauv nyob rau hauv nruab nrab ntawm lub thib nees nkaum xyoo pua tau pom Edvud Henneman. Nws hu ua nws "lub hauv paus ntsiab lus ntawm qhov tseem ceeb."

Brown thiab Bronk ib nrab ib xyoo pua ua ntej lawm luam tawm lawv tej hauj lwm nyob rau hauv txoj kev tshawb no ntawm lub hauv paus ntsiab lus ntawm cov lag luam ntawm ntau hom ntawm npag units. Lawv tau pom hais tias muaj ob txoj kev los tswj cov contraction ntawm nqaij fibers. Tus thawj ntawm cov - yog ua rau kom cov zaus ntawm cov hlab impulses thiab lwm yam - mus koom nyob rau hauv tus txheej txheem raws li ntau li ntau tau rau tus xov tooj ntawm lub cev muaj zog neurons.