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Bio year 2 > TNS + muscles > Flashcards

TNS + muscles Flashcards

1
Q

what is in the CNS

A

brain + spinal chord

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2
Q

peripheral nervous system (PNS)

A

all neurones that connect CNS to rest of body

  • SN carry impulse from receptor to CNS
  • MN carry impulse away form CNS to effector.
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3
Q

what is the somatic NS

A

under conscious control
used when voluntarily decide to do something
carries impulses to the body’s muscle

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4
Q

autonomic NS

A

work constantly
under subconscious control
used when body does something automatically
involuntary
E.g heart beat / food digestion
carries impulses to glands, smooth muscle (walls of intestine) and cardiac muscle.

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5
Q

what can the autonomic system be divided into

A

sympathetic NS

parasympathetic NS

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6
Q

what is the sympathetic NS

A 
fight or flight response 
increases activity 
when under stress
E.g noradrenaline 
increases heart rate, dilates pupils, pumps blood faster
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7
Q

what is parasympathetic

A 
rest and digest 
decreases activity 
relaxed response 
E.g. acetylcholine 
decrease in heart rate, breathing rate (after exercise)
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8
Q

gross structure of the brain

A

protected by the skull

surrounded by protective membranes (meninges)

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9
Q

cerebrum

A

control voluntary action

-E.g voluntary movement (walking) , reading , learning

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10
Q

cerebellum

  • if damaged?
  • receive/relay?
A

control unconscious functions

  • posture, balance and non voluntary movement
  • if damaged = jerky, uncoordinated movement
  • receives info from organs of balance in ears
  • relays to the cerebral cortex involved in motor control
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11
Q

medulla oblongata

A

used in autonomic control

  • control reflex actions controls heart/breathing rate
  • swallowing, coughing, peristalsis
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12
Q

hypothalamus

A

regulatory centre for temperature and water balance

  • main control of autonomic NS
  • controls complex behaviour (sleeping)
  • monitors plasma composition (water + gluc conc) = rich blood supply
  • endocrine gland so produces hormones
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13
Q

pituitary gland

A

stores and releases hormones that regulate body functions

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14
Q

function of the cerebrum

A
  • receives sensory info
  • send impulses along MN to effectors for a response.
  • highly convoluted (inc SA)
  • high SA = large capacity
  • split into left and right hemisphere - each hemisphere controls one half of the body
  • out layers of CH = cerebral cortex
  • LH receives impulses from RHS
  • ## RH receives impulses from LHS
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15
Q

anterior pituitary

A
  • front section
  • produces 6 hormones
  • inc FSH (follicle stimulating - reproduction + growth)
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16
Q

posterior pituitary

A
  • back section
  • stores and releases hormones from hypothalamus
  • E.g ADH in urine production
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17
Q

What part of the brain controls reasoning + decision making

A

frontal and prefrontal lobe of cortex

18
Q

where is movement controlled

A
  • primary motor cortex

- back of the frontal lobe

19
Q

reflex arc

A

pathway of neurones involved in a reflex action:

  • receptor (detects stimulus + AP in SN)
  • SN (impulse to spinal chord)
  • RN (connects SN to MN within spinal chord/brain)
  • MN (impulse to effector)
  • Response
20
Q

spinal chord

A
  • column of nervous tissue
  • surrounded by spine for protection
  • neurones along intervals of spinal cord pairs.
21
Q

knee jerk reflex

A
  • spinal reflex
  • leg tapped below kneecap
  • stimulus = stretch of patellar tendon
  • reflex arc
  • extensor muscle on top of the thigh contracts
  • RN inhibits the MN of the flexor muscle = relax
  • the contraction coordinated with the relaxation of the antagonistic flexor hamstring causes the leg to kick
  • after tap, leg is extended and rests.
22
Q

what could absence of knee jerk reflex mean

A
  • nervous problems

- multiple oscillations of leg = sign of cerebellar disease.

23
Q

blinking reflex / corneal reflex

A
  • cranial reflex (brain)
  • cornea of eye is irritated (dust)
  • stimulus triggers impulse along SN
  • impulse passes through RN in lower brain stem
  • impulse sent along branches of MN
  • motor response to close eyelids
  • consensual response (both close)
24
Q

why do doctors use corneal reflex

A
  • if reflex is present - lower brain is still functioning

- determines whether brain-dead on unconscious patients.

25
Q

survival importance of reflexes

A
  • very fast : reflex arc is short
  • not learnt - present at birth = provide immediate protection
  • involuntary response - prevents overload on brain as decision making parts of brain aren’t needed
  • considered everyday actions (upright and digestion control)
26
Q

skeletal muscle

  • function
  • fibre appearance
  • control
  • arrangement
  • contraction speed
  • length of contraction
  • structure
A
  • make up the bulk of muscle tissue
  • responsible for movement
    (biceps + triceps)
  • striated fibre appearance
  • voluntary control
  • regular arranged so muscle contracts in one direction
  • rapid
  • short
  • striped muscles (striations) + fibres are tubular + multinucleated
27
Q

cardiac muscle

  • function
  • fibre appearance
  • control
  • arrangement
  • contraction speed
  • length of contraction
  • structure
A
  • in heart
  • myogenic : contract without need for nervous stimulus
  • causes heart to beat in a regular rhythm
  • specialised striated
  • involuntary
  • cells branch and interconnect = simultaneous contraction
  • intermediate
  • intermediate
  • fainter striped muscles (striations) + branched + unnucleated fibres
28
Q

involuntary muscle

  • function
  • fibre appearance
  • control
  • arrangement
  • contraction speed
  • length of contraction
  • structure
A
  • smooth muscle
  • walls of hollow organs (stomach)
  • blood vessel walls
  • non-striated
  • involuntary
  • no regular arrangement : diff cells contract in diff directions
  • slow
  • can remain contracted for a long time
  • unstriped muscles + spindle shaped and unnucleated fibres.
29
Q

sarcolemma

A

plasma membrane around muscle fibres

30
Q

muscle fibres

A
  • skeletal muscles made up of muscle fibres
  • enclosed in sarcolemma
  • contain nuclei
  • longer than normal cells
  • formed due to many embryonic muscle cells fusing
  • parts of sarcolemma fold inwards (T tubules)
  • helps spread electrical impulses throughout sarcoplasm
  • ensures whole fibre contracts at the same time
  • lots of mitochondria for contraction
  • sarcoplasmic reticulum
  • extends throughout muscle fibre and has Ca2+ ions needed for muscle contraction.
31
Q

sarcoplasm

A

shared cytoplasm within muscle fibres

32
Q

Myofibrils

A
  • muscle fibres contain myofibrils
  • long
  • cylindrical
  • made of protein : actin and myosin
  • specialised for contraction
  • parallel = provides max force when contract
  • have alternating light + dark bands result in striped appearance
33
Q

actin

A
  • thinner protein filament
  • 2 strands twisted around each other
  • binding sites for myosin heads ~(normally blocked by tropomyosin)
34
Q

myosin

A
  • thicker protein filament
  • long
  • red fibres
  • globular heads allow it to move back + forth
  • head has a binding site for actin + ATP
35
Q

light bands /I band

A
  • appear light
  • regions where actin and myosin filaments don’t overlap
  • (known as isotopic bands/I bands)
36
Q

dark bands / A bands

A
  • presence of thick myosin filaments
  • myosin overlapped with actin
  • (known as anisotropic bands/A bands)
37
Q

Z - line

A
  • line at centre of each light band
  • distance between adjacent Z - lines = sarcomere
  • muscle contracts sarcomere shortens
38
Q

H-zone

A
  • centre of each dark band
  • only myosin filaments present
  • muscle contracts
  • H-Zone decreases.
39
Q

neuromuscular junction

A
  • MN meets a skeletal muscle fibre
  • AP reaches NMJ
  • stimulates Ca2+ channels to open
  • Ca2+ from synapse into synaptic knob
  • synaptic vesicles fuse with preS membrane
  • AC released into synaptic cleft (exocytosis)
  • AC diffuses across the cleft
  • binds to receptors on sarcolemma
  • Na+ channels open
  • depolarisation
  • AC broken down by ACE
  • forms choline + ethanoic acid
  • prevents overstimulation of muscle
  • choline + ethanoic acid diffuse back into neurone
  • recombined into AC using energy from mitochondria
40
Q

myosin and actin during muscle contraction - sliding filament model

A
  • tropomyosin prevents myosin from attaching to actin binding site
  • Ca2+ released from sarcoplasmic reticulum
  • tropomyosin mol pulls away from binding site on actin
  • myosin head attaches to binding site on actin
  • myosin head changes angle
  • moves actin mol along
  • ADP (bound to myosin head) is released
  • ATP fixes to myosin head
  • detaches myosin from actin filament
  • Ca2+ in sarcoplasm activate ATPase
  • hydrolyses ATP to ADP
  • releases energy
  • causes myosin head to return to original position
  • myosin head reattaches to binding site further along actin filament
  • cycle repeats
41
Q

how creatine phosphate provides ATP

A
  • creatine phosphate is stored in muscles
  • ADP is phosphorylated
  • creatine phosphate is a reserve supply of P
  • combines with ADP = ATP
  • generated ATP rapidly
  • used for short bursts of vigorous exercise
  • muscle relaxes, creatine phosphate replenished using P from ATP

Bio year 2 (11 decks)

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