Module 5.5 Flashcards
What is the autonomic nervous system ?
part of the nervous system responsible for controlling the involuntary motor activities of the body .
What is the central nervous system
the central part of the nervous system composed of the brain and spinal cord .
what is the peripheral nervous system
the sensory and motor nerves connecting the sensory receptors and effectors in the CNS .
What is the somatic nervous system
The motor neurones under conscious control .
what should a communication system in an organism include (1)
-detection of changes in the environment ,
-cell signalling to occur between al parts of the body .
what should a communication system in an organism include (2)
coordination of a range of effectors to carry out responses to the sensory input .
-suitable responses .
many environmental changes require rapid and well coordinated responses to ensure survival , explain this
this may involve a wide array of responses such as coordinated muscle action , control balance and posture , temperature regulation and coordination with the endocrine system , this is the role of the nervous system .
check figure 1 on page 90 for the organisation of the nervous sytem
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what does the human brain consist of
the human brain consist of mostly relay neurones which have multiple connections enabling complex neural pathways . Most of these cells are non myelinated cells and the tissue looks grey in colour .
what does the spinal cord consist of
the spinal cord also has many non-myelinated relay neurones making up the central grey matter . However , the spinal cord , also contains large numbers of myelinated neurones making up an outer region of white matter .
-MYELINATED NEURONES CARRY AN ACTION POTENTIAL UP AND DOWN SPINAL CORD FOR RAPID Communication , over long distances .
what is the role of the peripheral nervous system , what is composed of ?
the role of the peripheral nervous system is to ensure rapid communication between sensory receptors ,t he CNS , and the effectors .
-the PNS is composed of sensory and motor neurones , these are usually bundled together in a connective sheath to form nerves .
what do the neurones and dendrons do in the sensory nervous system
the sensory fibres entering the CNS are dendrons of the sensory neurones . These neurones conduct action potentials from the sensory receptors into the CNS . These neurones have thier cell body in the dorsal root ,l leading into the spinal cord and a short axon connection to other neurones in the CNS .
what is the function of the motor nervous system
the motor nervous system conducts action potentials from the CNS to the effectors . It is further subdivided according to the functions of the motor nerves .
what does the somatic nervous system consist of
motor neurones that conduct action potentials from the CNS to effectors that are under voluntary control (conscious ) control . This included the glands , the cardiac muscle and smooth muscles in the walls of the blood vessels . The airways and the walls of the digestive systme .
control of the effectors in the somatic nervous system
the control of many of these effectors does not require rapid responses and the neurones are mostly non-myelinated . There are at least twp. neurones involved in the connection between the CNS and the effector . These neurones are connected at small swellings called ganglia
what does the autonomic nervous system consist of
motor neurones that conduct action potentials from the CNS to the effectors that are not under voluntary control . This includes the glands , the cardiac muscle and smooth muscle int he walls of the blood vessels the airways and the walls of the digestive system .
the autonomic nervous system - control
the control of many of these effectors does not require rapid responses and the neurones are mostly non-myelinated / These are at least two neruones invovled in the connection between the CNS and the effector . These neurones are connected at small swellings called ganglia .
what does autoonomic mean
the autonomic nervous system means self governing and it operated to a large extent independently of conscious control . It is responsible for controlling the majority of the homeostatic mechanisms and so plays a vital role in regulating the internal environment of the body .
what can the autonomic nervous system be further divided into ?
the sympathetic system , which prepared the body for activity , and the parasympathetic system ,which conserves energy .
-The sympathetic and the parasympathetic systems differ in both structure and action .
what can the autonomic nervous system be further divided into ? (2)
They are antagonistic systems as the action of one system opposes the action of the other .
-In general , at rest , action potentials pass along the neurones of both systems at a relatively low frequency . This is controlled by subconscious parts of the brain . CHANGES TO THE internal conditions or stress , lead to changes int he balance of stimulation between the two systems .
difference between sympathetic system and the parasympathetic (1)
-consists of many nerves leading out of the CNS , each leading to a separate effector .
-Consists of a few nerves leading out of the CNS , which divide up and lead to different effectors .
difference between sympathetic system and the parasympathetic (12)
ganglia just outside of the CNS .
-Ganglia in the effector tissue .
difference between sympathetic system and the parasympathetic (3)
-long post ganglionic neurones (variable in length , dependent upon the position of the effector )
-short post ganglionic neurones .
difference between sympathetic system and the parasympathetic (4)
uses noradrenaline as the neurotransmitter .
-uses acetylcholine as the neurotransmitter
difference between sympathetic system and the parasympathetic ( 5)
increases activity - prepared body for activity
-decreases activity - conserves energy .
difference between sympathetic system and the parasympathetic (6)
most active at times of stress
-most active during sleep or relacation
effects of sympathetic system
increased heart rate
dilates pupils
increased ventilation rate
reduced digestive activity
-orgasm
effects of parasympathetic activity
decreased heart rate
constricts pupils
reduces ventilation rate
increases digestive activity
sexual arousal .
first main part of the brain
the cerebrum which is the largest part and organises most of our higher thought processes such as conscious thought and memory .
the second main part of the brain cerebellum
which coordinates movement and balances
what is the third part of the brian - the hypothalamus and pituitary complex
it organiseses homeostatic responses and controls various physiological processes .
where is the fourth part of the brain
wgucg coordinates many of the autonomic response
what does the cerebrum consist of
the cerebrum has two cerebral hemispheres which are connected via major tract of neurones called the corpus callosum . The outermost lyer of the cerebrum consists of a thin layer of nerve cell bodies called the cerebral cortex .
wht are the higher brain functions (1)
-conscious thought
-conscious actions (including the abilityt o override some reflexes )
higher brain functions (2)
emotional responses
-intelligence reasoning judgement and deciison making .
-factual memory
first area cerebal corter is subdivided into - SENSORY AREAS
Sensory areas receive action potentials indirectly from the senosry receptors . The sizes of the region allocated to receive input from different receptors are related to the sensitivity o fhte rea that inputs are received from .
the cebral cortex is dubdivided into asociagtion reas
compare sensory inputs with previous experience , interpret wht the inpput means an judge an appropriate resposne .
the ceebrl corex is sudivided mtor areas send action potentials to various effectors (muscle and glands )
The size of the regions llocated to del with different effectors are related to the complexity of the movmement , rneeded int he parts of the body s shown in f 2 . Motor areas ae ont he left side of the brain contorlt he effectors ont he right side of the bodya nd vice versa .
the cerebellum is invovled in what
it is invovled with balance and fine coordiantion of movement . To do this , it must receiebe information from many sensory receptors and process the information accuratel .
what are the sensoryr eceptors that supplt rhe information to the cerebllum include
th retina , the abalnce organs in the inner ear and spindle fibres in the muscles which give information and muscle length and the joints .
tip the conscious decisitions to contract volnarty msucles is intiiated in the cerebral cortext however
the cerebral cortex does not provide the complex signals required to coordinate complex movmeemnts .
fine control muscular movemenvements (1)
maintaining body position and balance , such as when riding a bicyle
fine conrol of muscle movmements (2)
judging the position of objects nd limb whie moving about or playing sport .
fine control movements (3)
tensioning muslces in order to use tools and ply muscial instruments effectively
fine control of muscle movements (5)
coordinting contraction and relaxation of antagnostic skeletal msucls when walking and running .
control reqruiing what
this control often reqruies learning . Once learnt such activities may become scond nture and ivnovle much unconscious conrol .
THIS SORT OF coordination requires complex nervous patheay are strengthened by practice . THE COMPPLEX ACTIVIT bcomes programmed into the cerebllum , and neuonres from the cerebllum conduct ction potentials to the mtoor areas so the mtoro effectors and cn be finel controlled .
how was the cerebruma nd cerebllum connected
connected by the pons
what does the hypothalamus and pituitary complex
the hypothalamus controls hoemostatic mechaniasms int he bod , it contains own senosr receptords , and act by negtive feedbavck to maintain a constant internal environemnt .
the hypothalamus controls - temperature regulation
TEMPERATURE REGULATION , THE HYPOTHALAMUS DETECTS CHANGES IN CORE BODY TEMPERATURE . HOWEVER , IT ALSO RECEIEVES , SENSORY INPPUT FROM TEMPERATURE RECEPTORS INT HE SKIN . iT WILL INITNIATE RESPOSNE TO TEMPERTURE CHANGE THAT REGULATE BDOYT EMPRTURE WITHINA NARROW RANGE . tHEE RESPOSNSES MA BE MEDITED BY THE NERVOUS STE OF THE HORMONAL (VIA PITUITARY GLAND )
Hypothalamus contorls OSMOREGULATION
Oosmoregulation , the hypothalamus contains osmorceptors that monitor the water potential in the blood .. When the water potential changes , the osomoregualtory center intinates response brin about a reversal of this change , the response are medited by the hormonal vi the pituitary glnd .
the pituitary gland cts in conjuctionw ith the hypothlamus . The pituisty glaand conssnits of two lobes .
The posteriror lobe is linked to the hpothalmus by specialised neurosucretory cells . HORMONES , such as ADH , which are manufactured in the hyptohalamus pass don the neurosecretor cells and are releaed into the blood from the pituitar glan d.
whats does the anterior lobe
the anterior lov produces its own hormones which are rlelased into the blood in response to relesing factors produced by the hypothalsmus . Those releasedin factors , are hormones that need to be transported only as short distnce from the h pothalmus .
These relaseasing gscctors are hormones that need to be transported onl a short distance fromt he hypothalmu to the pituarty .
hormones from the anteriori pituiary control number
of a physiologvila processes in the body inclduing repsosne to strss frowth reproduction and lactiaiton
Medulla Oblongata controls what
the medull oblongaata controls the non sketal msucles by sneding actions potenitals out through the autonomic nervous sytem . The emdulla oblongata conntains centres for regulating several vital processes
medulla oblongata (1)
the cardfiac centre whcih regualtes heart rate
medulla oblongata 3)
the vasomotor centre which reuglates circuation an dblood pressure
medulla oblongoata (3)
the respirator centre which controls the rate and depth of brething these centres receve sneosry informaiton and coordinate vital funcitons by negative deedbacj .
what is a reflex action
a response that does not invovle any processing by the brain
what is the knee jerk reflex
a reflex action that straightes the leg when the tendon below the knee cap is tapped .
what are reflex actions
they are responses to changes in the environemnt that o not invovle any processing in the brain to cooridnte the moemvemnt . The nerovu psahey is as short as possible so that the reflex is rapid .
nist refkex oatgwats consist of three neurones
SENSOR NEURONE –> RELAY NEURONE –> MTOOR NEURONE
the brain may be infomred that the reflex has happened but is not invovled in cooridnating hte repsosne . REFLEX ACTIONS ALAYS HAVE A SURVIVIAL VALE A REFLEX MAY BEUSED OT GET OUT OF DANGER AOID DAMAGE TO PART OF TH EBODY OR MAY BEUS ED TO MINIAIN BALNCE .
What is the blinking reflex
the blinking reflex causes a temproary closue of the yeelids to protect eyes from damage
what is the nervous pathway for thre blinking reflex
the nervous pathway for hte blinking reflex passes through part of the brian - in other words the reflex is a canial reflex . However , the pathway is direct pathay that does not invovle any thoguht processes in the higher part of the brain . SINCE THE RECEPTORS and the effecots ar ein the smr palce hti sis clld a relfex arc
Blinking is stimualted by sudden changes in the enviornemnt such as
-foreign object touchign the eye (the corneal reflex )
sudden bright light (optical reflex )
loud sounds
sudden movments vlsoe to the eye
corneal reflex whag is theiois reflex mediated by
a sensory neurone from the conrea which etners the pons . A synapse connects the sensory neurone to a relay neurone ,w hich passes the action potenital to the mtor neurone .
-The mtoor neurone passes out of the brain to the facial msucles causing the eyelid to BLINK . this is a very short and direct pathway so the conreal reflex is very rapid it takes baout seconds . CONREL REFLEX USUALLY CUSES BOTH EYES OT BLINK EVEN IF ONLY ONE CONREA ISA FFECTED .
HOW DOES THE SNESNORY NEURONE INVOVLED IN THE CONREAL REFLEX also pass to the ction potenital in myelinated neurones in the pons
these myelinted nueornes carry the action potenital ot the snensory region in the cerebal cortex to inofrm the higher centres of the brain that the stimulus has occured . This allows the reflex to overriden by conscious control .
-higher parts of the brain cerebal cortex can send inhibitory signals to the motor centre in the pons . The myelinted nueornes carrying impulse to and fom the cerebral cortex transmit aciton potenitals much more raipildhy than hte non mnelianted relay neuronen in the pons . THEREFORE THE INHIBITORY ACTION POTENITALS CAN PREVENT HTE FORMATION OF AN ACTION POTENITAL IN THE MTOOR NEURONE .
What is an optical reflex
this protects hte light sensitive cells of the retina from damage . The sitmululs is detected by he retina ad the reflex is MEDIATED by the optical centre in the cerbal corext . THe opticl reflex is a little slower than hte conreal reflex .
What is the knee erk reflex
is is a spinal reflex the nervous patheay passes through the spinal cord rather than through the brain
knee jerk reflex is invovled in what (1)
the knee jerk reflex is invovled in coordianted movememnt an dbalance . The muscle at the front of the thigh contracts to straighten the leg . This muscle is attahced ot the lower leg vi the patella tendon tht connecs the ptell to the lwoer leg bones at the front of the knee .
knee jerk reflex (2)
when the muscles at the front of the thgih are stretched specialsed stretch receptors called mmuscle psindles detect the increase in the length of the muscle . I this strentchis is unexpeed a reflex acion casues the contrciton of the same MUSCLE .
what is the mechiansms hat enables us to balance on two legs
legit the card aboe , when ur standing sitll the mmsucle in fornt of the high wils trethc if knee bending and laen backwar
conrciton of msucles striahens knee brings body back aboe so these repsoses are vryr paid
knee jerk reflex is weird it consiss of only two neruones
senosry neuorne —> motor neurones
knee jerk reflex why is it so weird informed highest aprt of the brain
as with other relfex actions the higher prts of the braian are ifnormed the relfc is occuring ubt s THERE IS NO RELAY NEURONE the brain cannot INHIBIT THIS REFLEX .
inhibition RELEIS ON THE RAPID MNYELIANTED NUEONES CARRYING THE INHIBTORA CTION POTENTILS TO THE SYNAPSE BEFORE THE MOTOR NEURONE IS STIMUTLED .
WHAT HAPPENS IN THE BASCENCE OF A RELAY NEURONE
the mtoor neurone is stimulated directly by th senosry neurone and ther eis sufficent delay to enbale inhibtin . This is hwy doctors test your reflexed by tappign the tendon below the knee cap it cuses an immediage reposne that cannot be inhibted .
what happens hwne we wlaking or running and hte knee msnut bend a nd wills timualte the msucle psindels
hwoever the compex pattern of nervous impulses coming form the cerbellum is able to inhiit the relfe contrctions . As action potenitals are sent to the muscles behding the thigh hamstring stimualting it to contrct . INHIBTORY ACTION POTENITALS ARE SENT TO THE SYNAPSE INT HE REFLEX ARC TO PREVENT HT REFX CONTRACTION OF THE OPPOSING MUSCLS .
WHAT is the cardiac muscle
muscle found in the heart walls
what is the involuntayr muscle
smooth muscle that contracts without conscious control
what is the neuromsuculr junction
the strcuture at which a nerve meets the muscle , it is similr in action to a synapse .
skeletal (stirated ) muscle
muscle under voluntry control
muscles compsoed of cells arranged to form fibres . These fibres can contract to become shorter which produces a force
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how is contraction achieved
b the intereaction between two proteinf ilaments (ctin and myosin ) , in the muscle cells . Muscle cannot elonagte without an ANTAGONSIT .
-tHEREFORE MUSCLES are usually arrange din opposing pairs , so that one contracts as the other one elonages . IN SOME CASES the antagonsit may be elastic recoil or hdyrostatic pressure ina chamber
what are the three types of muscle
involunrty
cardiac
and volunatry
give a lil explnantion of involuntary smooth muscles
involuntary smooth m uscle consists of individual cells tapered a tboth ends (spindle shaped ) . At rest , each cell is about 500 micrometer long anf 5 micrometer wide . Each cell contins a nucleus an dbundles of action and myosin .
-The type of muscle contracts slowly and regulary . It does not tire quickly it is cntrolled by the autonomic nerbous system .
give a lil explanation of cardiac muscle
cardiac muslces forms the musucalr part of the ehrt . The individual cells form long fibres which branch to form corss brides between the firbes .
-THESE CROSS BRIDGES help to ensure that electricl stimultion psreads eenly over the alls of the chambers . Whe the msucles contracts hti rrageemnt also enusres tht hte contraction is a squeeeing aciton rather than one dimensional .
cardiac muscle (2) cells are joined by intercalaed discs
the cells are jjoined by itnercalted discs . These are sprislised cell surface memebrane fused to produce gap juncions that allow free diffusion of ions between the cell s . Sction potenitals pass easily and wuickl long and betweent he cardiac musle firbes .
CARDICAC MUSCLES CONTRACTING AND RELAXING CONTINUOUSLY THROUGHOUT LIFE
It can contract powerfully and does not fatigue easily . Some muscle fibres int he heart are modififed to carry electrical impusles . These coordinate the contraction of the chamber walls . HERT MUSCLE IS MYOGENIC it can initiate its on contraction , hwoever the rate of contraction is normally controlled byt he SSAN .
-CARDIAC muscles appears stirrated when viewed udner the microsocope
voluntary (skeletal or striated) mucle
skeeltal msucles occurs at the joins int he skeleton . CONTRACTION causes movmement of the skeleton by bending or straihgening the joint . THe muscle arr arranged in pairs called antagonsitic pairs when one contracts , the other elongates .
voluntary part 2
the msucle cells form fibres of about 100 micrometer sind iamter each of the fibres is mutlinuclet contains many nuclei and is surroudned by a memrban claled the sarcolemma
what is the muscle cell cytoplasms known as
sarcoplasms , and is specialised ot contian mny mitochondria and an extensive sacroplasmic reticulum
how is the contents offirbes arranged into a number of myofibrils
which are th contractile elements , these myfoibrisla re divided into a chian of usbunits called sarcomeres , sarcomeres ocntrain the portein filments actin and mysoisn
how are actin nd mysosina rranged
in a particular banded pattern ,w hich igves the muscle a stripes or striated apperance ,d ark bands known as a bands and hte lighter bands are i bnds VOLUTNAR MUSCLES CONRACT WUICKLA ND PWOERFULL Y BUT ALSO FATIGUE QUICKL
wHAT IS THE neuromsucualr junction
the skeletal msucle is under voluntrary control its contractions are sitmulted by the somatic nerovus syrem , the junction ebtween the nervous sytem and he muscl eis claled he nerumuscualr junction it has mny similairties o asyanse .
stimualtion of contraction (1)
action potentials arriving at the end of the axon open calcium ion channnels in the membrne . Calcium ions flood into the end of the acon
stimultion of contraction (2)
vesicles of acetylcholine move towards and fuse wirtth the end of the membrane
stimulation of contraction 3
acetyul choline moielcules diffuse across the gap nd fuse with receptors in the carcolemme
stimulation of contraction
this opens sodium ion channels hwich allow sodium ions to enter the muscle fibre causing depolariaition of the srolemme
stimulation of contraction 5
a wave of depoalriisaiton spread along th arcolemma and odwn transverse tubules in the muscle ifbre
what is the motor unit
some motor neurones stimualte single muscle ifbres . hwoever , many motro neurones divide and connec to several msucl eifbres . Allt hese muscl efibres ocntrac totgether porviidng asornger conraciton ,t his is clled a motor unit .
what is creatine phospahte
a compound in msucles that act as a store of phospahates and can supply phospahtes o mke ATP RAPIDL .
strucutre of the myofibrils what does it cosnsits of
MYOFIBRILS are the contractile units of skeleal muscles and contain two types of protein filament .
THIN FILAMENTS , which are ligned to make up the light band these are held together by the Z LINE .
thick filaments which make up the DARK BAND .
THE THICK AND THIN FILAMENTS OVERLAP WHERE
but in the m iddle of the dark band there is no overlap this is called the H ZONE .
-The idsance , betwen two z lines called a sarocmere , this is functional unit of the msucle a rest a sacromere is 2.5 micrometres .
thin filaments
the thin filaments are acitn . Each filaments consists of two chains , of actin subunits , teisted around eachother . Wound , around the actin is a molecule of tropomysoisn to which are attached to globualr moelcules of troponin .
thin filaments part two
each troponin , complex consinsts of three polypeptides one binds to actin one tropomysoisn , and the third binds to lcium when it is avaialble , . RTropomosisn and ropnina e part of the mechaisnsism is control , musuclar contraction ,a t the rest of these moelcules coer bidning sites of the thick filamens can bind .
what are the thick filaments
each thick filament cosnists of a bundle of mysoin meolcuels . Each m nysoisn moelcuel has two protruding heads , which sitkc ou at ach end of the moelcule These head are moile and can bidn to the acitn hen the bidnign sites are epose .
what is the sliding filament hypotheisis
during contraction the light band and he H zone ges shorer . tHEREFORE THE Z LINE MOVES CLOSER TOGETHER , AND THE SACROMERE GETS SHORTER . tHEIR OBSERVATION LED TO THE SLIDING FILAMENS , HYPOTEHSIS , during contraction , the thick and thin filaments lside past another .
what is the mechanism of contraction
the sliding action is caused by the movement of the mysoin , heads . When the muscle is stimualted tropomysoisn is moved , aside , exposign , the bidning sites on the actin . The myosin , heads attavh and move causing th actin slide past the myosin .
control of contraction (1)
when the muscle is stimulated , the ction potential passes along the sarcolemma , and down the tranverse tubulues (t tubules) intot he muscle fibres .
control of contraction (2)
the action potentials is carried to the sarcoplasmic reticulum , which stores calcium ions and cuses the release of calcium ions into the sarcoplasms .
control of contraction 3
the calcium ions bind to the troponin , which alters the shape pulling the tropomysoin aside , this exposed the bidnin sites ont he acitn .
control of contraction 4
myosin heds bidns o the cting ofrming cross bridges between the iflaments .
control of contractions 5
the mysoin heads moving pulling the ctin filament past the myosin filament
control of contraction 6
the mysoin heads deach fromt he actin and bind again furhter up the actin filament .
-MILIOSN of cross bridges , can be formed , between the ctin , and the mosin filaments , Once the contraction has occured ,t he calcium ions re rapidl pumped back into the sarcoplsmic reituclum allowing the muscle to relax .
role of ATP (1)
ATP SUPPLIES energy for contractio , part of the myosin head actd as ATPASE ,and can hydolyse ATP to ADP inorganic phosphate rleasing energy .
role of atp 1
the myosin head attaches to the actin filament , forming a cross bridge .
role of atp 2
the myosin head moves causing the thin filament to slide past the myosin filament . This is the power stroke , during the power storke ADP and Pi are released from the myosin head .
role of atp 3
after the power storke , new atp moeleucle attahces to the myosin hea d, breaking new cross bridge .
role of atp 4
the myosin , heads then return to its original positiosn ,a s the ATP is hdyorlysed releasing the energy to make this movement occur . THE MYSOSIN , head can now make a new cross bridg further across the actin filament .
maintaininng the supply of atp
there are millions of myosin heds invovled in musce contracion there is a huge requirement for atp , atp must be very quick;y regernred very quickly in order to allow continued contractin .
first way atp supply is mintined
aerobic respiRION in mirochondira muscle tissues contains a large nummber of mitochondira , in which aerboic respiration can occur .
-THE BOHR effect , helps to release more oxygen , from haemoglobin in the blood . HOWEVER , during intensity activity ,t eh rate at whih ATP , can be produced will be limited , byt he delivery of oxygen to muscle itssue .
second way of atp is maintained
anaerobic respirtion in the sarcoplasms , of the muscle tissues . Anaerobic respiration can release a little more ATP , from the respiratory substrates . However , it leads to the production of lctacte acid ,w hich is toxic . NAERBOIC , respriation onl last a few seconds before lactic cids buil up starts caus efatigue .
third way of atp is maintained
creatine phosphate , in the sarcoplasms , acsts as revseve store of phosphate groups . The phospahte , can be transferred fromt he creaine phosphae ADP , oelcules creating ATP moelcules veyr rapidly , The enzymes creain phosphotransferas eis invovled . The supply , of creting phsopahte is sufficent to support msuclar contravtion for futher -4 seconds .
