TNS + muscles Flashcards
1
Q
what is in the CNS
A
brain + spinal chord
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.
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
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.
5
Q
what can the autonomic system be divided into
A
sympathetic NS
parasympathetic NS
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
7
Q
what is parasympathetic
A
rest and digest decreases activity relaxed response E.g. acetylcholine decrease in heart rate, breathing rate (after exercise)
8
Q
gross structure of the brain
A
protected by the skull
surrounded by protective membranes (meninges)
9
Q
cerebrum
A
control voluntary action
-E.g voluntary movement (walking) , reading , learning
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
11
Q
medulla oblongata
A
used in autonomic control
- control reflex actions controls heart/breathing rate
- swallowing, coughing, peristalsis
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
13
Q
pituitary gland
A
stores and releases hormones that regulate body functions
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
15
Q
anterior pituitary
A
- front section
- produces 6 hormones
- inc FSH (follicle stimulating - reproduction + growth)
16
Q
posterior pituitary
A
- back section
- stores and releases hormones from hypothalamus
- E.g ADH in urine production
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
survival importance of reflexes
- 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
skeletal muscle
- function
- fibre appearance
- control
- arrangement
- contraction speed
- length of contraction
- structure
- 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
cardiac muscle
- function
- fibre appearance
- control
- arrangement
- contraction speed
- length of contraction
- structure
- 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
involuntary muscle
- function
- fibre appearance
- control
- arrangement
- contraction speed
- length of contraction
- structure
- 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
sarcolemma
plasma membrane around muscle fibres
30
muscle fibres
- 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
sarcoplasm
shared cytoplasm within muscle fibres
32
Myofibrils
- 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
actin
- thinner protein filament
- 2 strands twisted around each other
- binding sites for myosin heads ~(normally blocked by tropomyosin)
34
myosin
- thicker protein filament
- long
- red fibres
- globular heads allow it to move back + forth
- head has a binding site for actin + ATP
35
light bands /I band
- appear light
- regions where actin and myosin filaments don't overlap
- (known as isotopic bands/I bands)
36
dark bands / A bands
- presence of thick myosin filaments
- myosin overlapped with actin
- (known as anisotropic bands/A bands)
37
Z - line
- line at centre of each light band
- distance between adjacent Z - lines = sarcomere
- muscle contracts sarcomere shortens
38
H-zone
- centre of each dark band
- only myosin filaments present
- muscle contracts
- H-Zone decreases.
39
neuromuscular junction
- 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
myosin and actin during muscle contraction - sliding filament model
- 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
how creatine phosphate provides ATP
- 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
