Muscular System Flashcards
(101 cards)
1
Q
what are the 4 main functions of muscle
A
producing body movements. stabilising body positions.
storing and moving substances.
generating hear
2
Q
what are the 3 types of muscle
A
skeletal
cardiac
smooth
3
Q
describe skeletal muscle
A
connect to bone via tendons.
long cylindrical multinucleated cells.
obvious striations.
rapid and powerful contractions.
under voluntary control
4
Q
describe cardiac muscle
A
makes up walls of heart.
branching and usually uninucleate.
striated cells.
under involuntary control.
5
Q
describe smooth muscle
A
lining of organs, arteries and airways.
spindle-shaped, uninucleate cells.
non-striated.
under involuntary control.
6
Q
name the structure of skeletal muscle (in order)
A
myofibril - muscle fibre - fascicles - muscle
7
Q
name the layers of skeletal muscle (in order)
A
endomysium, perimysium , epimysium
8
Q
what is the sarcolemma
A
the plasma membrane of a muscle cell
9
Q
what are t-tubules
A
infolding of sarcolemma - quickly spread an AP through muscle fibre
10
Q
what is the sarcoplasm
A
the cytoplasm of a muscle cell; contains large amounts of glycogen and myoglobin
11
Q
what wraps around each myofibril
A
sarcoplasmic reticulum
12
Q
function of sarcoplasmic reticulum
A
when muscle is at rest, it stores calcium.
when stimulated, calcium is released
13
Q
function of myofilaments and sarcomeres
A
myofibrils contain this and thin filaments arranged into sarcomeres - thin are composed of actin, thick are composed of myosin
14
Q
what are the 5 different bands/discs/zonese/lines
A
Z disc
I band
A band
H zone
M line
15
Q
describe thick filaments (myosin)
A
thick filament composed of myosin
has a tail and two heads
contains binding sites for actin and for ATP
16
Q
describe thin filaments (actin)
A
composed of actin, troponin, tropomyosin.
actin contains binding site for myosin.
tropomyosin blocks myosin binding site.
tropomyosin held in place by troponin
17
Q
what are the 3 phases of muscle contraction
A
neuromuscular junction; AP travels along motor neuron and moves across synapse.
Excitation-contraction coupling; AP travels along sarcolemma, causing release of calcium
Cross-bridge cycling; myosin head bind with actin, allowing for contraction
18
Q
describe the process of neuromuscular junction
A
- AP travels along a motor neuron to the axon terminal
- change in memb pot causes voltage-gated Ca channels to open
- Ca enters the axon terminal
- Ca signals neurotransmitter filled vesicles to move towards the memb
- Vesicles mere with memb and release neurotransmitter via exocytosis
- neurotransmitter diffuses across synaptic cleft
- neurotransmitter binds to ligand-gated Na channels on muscle
19
Q
describe the process of excitation-contraction coupling
A
- AP arrives at the axon terminal and ACh is released
- ACh binds to the ligand-gated Na channels and Na enters the muscle
- AP runs along sarcolemma and t tubules initiating release of Ca
- Ca binds to troponin, moving tropomyosin and exposing the binding site on actin
- Myosin binds to actin and pulls the thin filaments toward the thick filaments
- AP stops and Ca is transported out of the sarcoplasm
- Troponin moves the tropomyosin back to the blocking the binding sites on actin
20
Q
describe the process of cross-bridge cycling
A
- myosin heads break down ATP and become reorientated
- Myosin heads bind to actin forming cross bridges
- myosin heads rotate towards the centre of the sarcomere (power stroke)
- APT binds to myosin heads , causing myosin to detach from actin
21
Q
what are the 4 factors that increase contractile force (aka more cross bridges attached)
A
large number of muscle fibres recruited
large muscle fibres
high frequency of stimulation
stretch of sarcomere
22
Q
what are the 6 muscle contractions
A
agonist
antaogonist
synergist
muscle tone
isotonic
isometric
23
Q
what is agonist
A
the contracting or shortening muscle
24
Q
what is antagonist
A
the relaxing or lengthening muscle
25
what is the synergist
assists the agonising muscle
26
what is muscle tone
continuous and partial contraction of muscleq
27
what is isotonic
contraction involving muscle shortening or lengthening
28
describe Type I Fibres (skeletal muscle)
slow oxidative.
low tension produced.
high resistance to fatigue.
slow time to peak force.
slow duration of contraction
29
what is isometric
contraction without a change in muscle length
30
describe Type IIA Fibres (skeletal muscle)
fast oxidative/glycolytic.
moderate tension produced.
high resistance to fatigue.
fast time to peak force.
fast duration of contraction.
31
describe Type IIX fibres (skeletal muscle)
fast glycolytic.
high tension produced.
low resistance to fatigue.
fast time to peak force.
fast duration of contraction.
32
what are the 3 types of energy for contraction
ATP-CP
Anaerobic Glycolysis
Aerobic
33
describe ATP-CP
uses creatine phosphate stored in muscle to produce ATP.
creatine phosphate -> ADP + P -> ATP + creatine.
no oxygen required.
15 seconds of energy.
34
describe anaerobic glycolysis
uses glucose in the blood to produce ATP.
Glucose -> 2 ATP and 2 Pyruvic acid.
no oxygen required.
2mins of energy.
35
describe aerobic energy
uses carbs, fat and protein to produce ATP.
oxygen required.
36-38 ATP
ATP can continue to be produced until fuel stores depleted.
36
what are varcosities
the swellings in the neuron that contain vesicles with neurotransmitter - they form diffuse junctions
37
what are gap junctions
basically the space instead of t-tubules (in skeletal muscle).
nuerotransmitters are released by varsities and bind to ligand-gated Na channels
38
why do smooth muscle have less developed sarcoplasm reticulum
they can't hold as much calcium; gets calcium from extracellular fluid
39
how does a smooth muscle contraction compare to a skeletal muscle contraction
types of neuromuscular junctions and varcosities.
gap junctions vs t-tubules.
Ca coming from sarcoplasmic reticulum vs extracellular fluid.
Ca binds to calmodulin vs troponin.
power stroke causes contraction; spiralling vs shortening
40
identify the 5 external structures of the eye
eyelid
eyelashes
eyebrows
lacrimal caruncle
conjunctiva
41
what is the fibrous tunic of the eye and what are the 3 main structures of it
it is the outermost layer.
cornea
sclera
canal of schlemm
42
function of cornea
provides a window for light to enter the eye
43
function of sclera
provides protection and acts as an anchor for extrinsic eye muscles
44
function of canal of schlemm
drains aqueous humor from anterior cavity
45
what is the vascular tunic and what are the 3 structures of it
middle layer.
choroid
cillary body.
iris.
46
function of choroid
contains extensive capillary network supplying retina and sclera
47
function of ciliary body
includes ciliary muscle and processes which holds lens in place
48
function of iris
contains blood vessels, pigment and smooth muscle which adjusts pupil
49
what is the retina and what are the 4 structures of it
the inner tunic.
photoreceptors.
macula lutea.
fovea centralis
optic disc
50
function of photoreceptors
rods and cones - turns into neural signal
51
function of macula lutea
yellow spot in centre of retina, allow for high visual acuity
52
function of fovea centralis
centre of macula containing only cones for high visual acuity
53
function of optic disc
where optic nerve leaves the eye (blind spot)
54
function of anterior cavity
contains aqueous humor which nourishes eye structures
55
what are the 3 internal structures of the eye
anterior cavity
posterior cavity
lens
56
function of posterior cavity
contains vitreous humor which maintains shape of eye
57
function of lens
focusses the light that passes through it onto the retina
58
describe the pathway of light through the eye
cornea
anterior cavity
pupil
lens
posterior cavity
retina
light goes through all the layers of cells, hits the back of the retina (pigment epithelium), then gets absorbed by photoreceptors (rods and cones), transmitted to bipolar cells, then to ganglion cells and back to the brain
59
what is accomodation
the ability of the eye to change its focus from distant to near objects (and vice versa). this is achieved by the lens changing its shape
60
what is refraction power
the ability of the lens to bend or refract light to focus them onto the retina
61
what is the focal length
the distance between the lens of the eye and the retina
62
describe what happens with viewing objects that are short in distance
the lens is round and thicker
lessens the focal length
increases refractive power
63
describe what happens when viewing objects that are far in distance
the lens is thinner and flatter
reduces refractive power
increases the focal length
64
describe rods in vision
most numerous.
operate in dim light.
dont discriminate colour.
many rods feed into a single ganglion cell (fuzzy and indistinct images)
65
describe cones in vision
less numerous.
operate in bight light.
discriminate colour.
one code feeds into a single ganglion cell (detailed and highres vision)
66
describe visual signal transduction in the dark
1. in the dark, trans-retinal converts back to its cis-retinal form.
2. Na moves into outer segment via ligand-gated sodium channels
3. Ca moves into rod through voltage-gated Ca channels
4. influx of Ca causes the release of neurotransmitter
5. binding of neurotransmitter to bipolar cell causes hyperpolarisation
6. no neurotransmitter released at synaptic cleft of bipolar cell
7. no depolarisation of gangion cell
8. no AP along optic nerve
67
describe visual signal transduction in the light
1. absorption of light triggers a change from cis-retinal to trans-retinal
2. change in retinal produces a series of reaction that close Na channels in rod
3. Ca channels in synaptic cleft close
4. no neurotransmitter released
5. bipolar cell remains depolarised
6. neurotransmitter released at synaptic cleft of bipolar cell
7. ganglion cell depolarised
8. AP along optic nerve
68
what is cis-retinal and trans-retinal
the form of the photoreceptor
in the dark, retinal is cis-retinal (bent)
with light absorption, turns into trans-retinal
69
what does the term bleaching mean
trans-retinal seperates from opsin
70
what does the term regeneration mean
cis-retinal binds with opsin
71
what is the pathway of the axons that terminate in the thalamus
optic nerve - optic chasm - optic tract - thalamus - primary visual area
72
what is the pathway of the axons that terminate in the midbrain
optic nerve - optic chiasm - optic tract - superior colliculi - various eye muscles
73
what are the 3 structures of the external ear
auricle
external auditory canal
tympanic membrane
74
what are the 6 structures of the middle ear
malleus
incus
stapes
oval window
round window
auditory canal
75
what are the 5 structures of the inner ear
bony labyrinth
membranous labyrinth
semicircular canals
vestibule
cochlea
76
describe the function of the auricle
direct sound waves to the external auditory canal
77
function of external auditory canal
direct sound waves to tympanic membrane and protection
78
function of tympanic membrane
vibrates in response to sound waves and protection
79
function of ossicles
transmit vibrations from tympanic membranef
80
function of oval window
receive vibrations from stapes, allow for fluid movement in cochlea
81
function of round window
allow for fluid movement in cochlea
82
function of auditory canal
allows for the equalisation of air pressure in middle earf
83
function of bony labyrinth
outer bony layer of inner ear, contains perilymph
84
function of membranous labyrinth
in membranous layer of inner ear, contains endolymph
85
function of semicircular canals
contains receptors for equilibrium
86
functions of vestibule
contains receptors for equilibrium
87
function of cochlea
contains receptor for hearing
88
what is equilibrium
a state of balance and stability
89
what contains the receptors for static equilibrium
vestibule
90
what contains the receptors for dynamic equilibrium
semicircular canals
91
what detects horizontal movements and changes in head orientation
utricle and saccule
92
what detects rotational movement around an axis or pivot point
semicircular canals
93
what is static equilibrium
maintaining position of the body relative to the force of gravity
94
describe how static equilibrium works
bony vestibules contain saccule and utricle. within the walls of these are maculae.
maculae have hair cells and supporting cells.
on top of the hair cells are otolithic membrane and otoliths.
when head tilts of linear movements, otoliths move, dragging the membrane and bending the hair receptors which cause a receptor potential
95
describe dynamic equilibrium
semicircular canals have semicircular ducts. each duct has ampulla. ampulla have small elevation called crista.
crista has hair cells, surrounded by gelatinous cupula.
head moves, hair and cupola move, and endolymph in semicircular ducts lags - causing bend of hair cells and generates receptor potential
96
describe the process of hearing
1. sound waves directed into external auditory canal via auricle
2. sound waves strike tympanic memb causing vibrations
3. vibrations transmitted through ossicles
4. vibration of stapes at oval window causes movement of perilymph in Scala vestibule
5. movement of perilymph continues to scala tympani, pushing against round window
6. movement of perilymph in scala vestibule causes vibration of vestibular memb
7. vibration of vestibular memb causes movement of endolymph
8. movement of endolyoh in cochlea duct causes vibration of basilar membrane
9. bends hair cells against tectorial membrane
10. causes receptor potential
97
what is gustation
molecules, dissolved in saliva, interact with taste receptors
sour sweet bitter salty umami
98
what are the 3 cells of taste buds
supporting cells - supports and replaces gustatory receptor cells
gustatory receptor cells - contain microvilli which extend through taste pore
basal cells - produce supporting cells
99
what are tastants
chemicals that stimulate gustatory receptor cells
100
how are salty sour sweet bitter and umami foods received
salty - Na channels
sour - H channels
sweet, bitter, umami - G proteins and second messengers
101
what are odorants
chemicals that stimulate olfactory receptors
