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Biomedical Sciences BS22001 > πŸ’ͺ🏻&πŸ€” > Flashcards

πŸ’ͺ🏻&πŸ€” Flashcards

1
Q

A band

A

DARK
stacked set of thick filaments (myosin) + portion of thin filaments (actin)

actin overlaps on both ends of the thick filaments

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2
Q

H zone

A

lighter area in the middle of the A band, where the thin filaments do not reach

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3
Q

M line

A

extends vertically down the middle of the A band; is in the middle of the H zone

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4
Q

I band

A

LIGHT

remaining portions of the thin filaments

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5
Q

Z line

A

dense, vertical line, located in the middle of each I band;

flat cytoskeletal disc that connects the thin filaments of two adjoining sarcomeres

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6
Q

sarcomere

A

smallest unit of skeletal muscle that can undergo muscle contraction;
area between two Z lines

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7
Q

Transverse (T) tubules
location?
runs from _______ to the _______ of the muscle fibre => ____ (slow/rapid) spread of the AP

A

at the junction of A and I band, where surface membrane dips into the muscle fibre;
runs from surface to the central portions of the muscle fibre => rapid spread of the AP

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8
Q

sarcoplasmic reticulum (SR) is modified _______ that consists of fine network of ____________ enclosed compartments surrounding each myofibril like a __________ [think clothing]

A

sarcoplasmic reticulum (SR) is modified ENDOPLASMIC RETICULUM that consists of fine network of INTERCONNECTED MEMBRANE enclosed compartments surrounding each myofibril like a MESH SLEEVE

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9
Q 
lateral sacs (terminal cisternae)
separated from adjacent T tubules by \_\_\_\_\_\_, \_\_\_\_ [substance] storages;
the spread of \_\_\_\_ down a T tubule triggers release of \_\_\_\_ [substance] from the SR into \_\_\_\_\_\_\_ [substance/organelle in the cell]
A

separated from adjacent T tubules by a slight gap, Ca2+ storages;
the spread of AP down a T tubule triggers release of Ca2+ from the SR into cytosol

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10
Q

foot proteins aka ryanodine receptors

A

bridge the gap between lateral sacs and T tubules, are Ca2+ release channels

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11
Q 
dihydropyridine receptors
are also called \_\_\_\_\_\_\_\_\_
why are they called dihydropyridine?
nature of their work?
what electrical activity activates these channels?
A

= T tubule receptors;
can be blocked by the drug dihydropyridine
voltage-gated sensors;
local depolarisation activates these channels

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12
Q

AP –> local depolarisation –> T tubule receptors trigger the opening of _______ –> opening of the ________ not directly associated with the ________ –> Ca2+ released into _______ β€”> exposure of the ______ on the ____ molecules so that they can link with ________ cross bridges –> beginning of the cross bridge cycle

A 
ryanodine receptors
ryanodine receptors
T tubule receptors
cytosol
binding sites
actin
myosin
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13
Q

Cardiac muscle AP

________ plateau = _________ contraction => ________ (adequate/inadequate) ejection time

plateau due to activation of ________ channels (why this name?)

A

PROLONGED plateau = PROLONGED contraction => ADEQUATTE ejection time

plateau due to activation of L-TYPE Ca2+ channels (L because opened for Long)

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14
Q

actin is build from chains that….

A

intertwine

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15
Q

tropomyosin looks like a _____ [sewing kit], physically covers ______

A

thread like

actin

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16
Q

troponin is made up of 3 subunits, what does each bind to?

A

one binds to tropomyosin
one to actin
one combines with Ca2+ ions released from lateral sacs

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17
Q

Myosin looks like ______ [sports gear], _____ is twisted

globular head has two sites, what does each bind to?

A

like a golf club
shaft is twisted
globular head has two sites: one for binding of actin, the other one for myosin ATPase

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18
Q

A band (during contraction)

A

stays same width (A band = thick filaments, hence stays the same)

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19
Q 
I band (during contraction)
width \_\_\_\_ (decr./same/incr.)
\_\_\_\_\_\_ filaments are \_\_\_\_ overlapping \_\_\_\_\_ filaments
A

width πŸ”½

THIN filaments are NO LONGER overlapping THICK

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20
Q

H zone (during contraction)

A

width πŸ”½ (thick filaments not overlapping thin)

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21
Q

cross bridge cycle has 4 steps:

A

binding
power stroke
detachment
binding

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22
Q

(1st) Binding [of the cross bridge cycle]

what binds to what?

A

myosin cross bridge binds to actin molecule

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23
Q

Power stroke [of the cross bridge cycle]
what happens?
what is the consequence?

A

cross bridge bends, pulling thin myofilament inward

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24
Q

Detachment [of the cross bridge cycle]
it happens at the end of what?
what happens later?

A

cross bridge detaches at end of power stroke and returns to normal conformation

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25
(2nd) Binding [of the cross bridge cycle] | what binds to what? what is the next step?
cross bridge binds to more distal actin molecule; | cycle repeats
26
CNS (____) ---> ______ ----> _____ & ______ & _______ & _______
``` central nervous system PNS = peripheral nervous system somatic efferent enteric (ENS) autonomic (ANS) somatic and visceral afferent ```
27
ANS ----> ______ & ______
sympathetic division | parasympathetic division
28
SNS transmitters (2), specify order
pregangionic neurone: ACh (cholinergic) | postganglionic neurone: usually NA = noradrenaline (adrenergic)
29
PSNS transmitters (2), specify order
pregangionic neurone: ACh (cholinergic) | postganglionic neurone: ACh (cholinergic)
30
ACh is synthesised by...
choline acetyltransferase (CAT)🐱🐱🐱
31
ACh is degraded to _____ and _____ by
acetate choline acetylcholinesterase (AChE)
32
``` type of G protein: ____ G protein coupled receptor: M1 action: ______ affected organ(s): stomach effect on the organ: ______ ```
Gq simulation of phospholipase C πŸ”Ό acid secretion
33
``` type of G protein: Gi G protein coupled receptor: ____ action: inhibition of adenylyl cyclase & _________ affected organ(s): heart effect on the organ: ______ ```
M2 opening of K+ channels πŸ”½ rate
34
type of G protein: Gq G protein coupled receptor: _____ action: simulation of phospholipase C affected organ(s): salivary glands [effect?], ______ [contraction] * _______ is indirectly relaxed by ____ receptor activation due to release of ______ from neighbouring endothelial cells
M3 increased secretion visceral smooth muscle Vascular smooth muscle M3 nitric oxide
35
``` type of G protein: Gs G protein coupled receptor: ____ action: ________ affected organ(s): heart effect on the organ: ______ ```
Ξ²1 stimulation of adenylyl cyclase πŸ”Ό rate & force
36
``` type of G protein: ____ G protein coupled receptor: Ξ²2 action: stimulation of adenylyl cyclase affected organ(s): ______ effect on the organ: ______ ```
Gs bronchial and vascular smooth muscle relaxation
37
``` type of G protein: Gq G protein coupled receptor: ____ action: stimulation of phospholipase C affected organ(s): _____ effect on the organ: ______ ```
Ξ±1 vascular smooth muscle contraction
38
``` type of G protein: _____ G protein coupled receptor: Ξ±2 action: ________ affected: NorAd release effect: ______ ```
Gi inhibition of adenylyl cyclase inhibition
39
NorAd is reuptaken by two transporters:
``` uptake 1 (U1), and uptake 2 (U2) ```
40
NorAd is metabolised by two enzymes:
``` monoamine oxidase (MAO,) and catechol-O-methyltransferase (COMT) ```
41
examples of synergistic muscles (synergists) in upper limb (2 pairs)
biceps brachii & brachialis | triceps brachii & anconeus
42
examples of flexors in upper limb (2)
Biceps brachii | brachialis
43
examples of extensors in upper limb (2)
triceps brachii | anconeus
44
axial muscles control...
movements of the trunk (maintaining posture)
45
proximal (or girdle) muscles are found in _____, ______, ______ and ______ they [action]
the shoulder, elbow, pelvis and knee mediate locomotion
46
distal muscles move ______, _____, and ______ they [action]
the hands feet digits allow fine manipulation of objects by the hand
47
Axons of LMNs (lower motor neurones) exit the spinal cord in _________
the ventral roots
48
Each ventral root joins with a ________ to form a ___________ (30 pairs) which contains sensory and motor fibres
dorsal root | mixed spinal nerve
49
Motor neurones | belong to a spinal segment: _______ (C) ______, _______ (T) _______, ______ (L) ______ and ______ (S) _____
cervical 1-8 thoracic 1-12 lumbar 1-5 sacral 1-5
50
Motor neurones are not distributed equally within the spinal cord: greater number in the ________ (______) supplying the arm and _________ (______) supplying leg
``` cervical enlargement (C3 - T1) lumbar enlargement (L1-S3) ```
51
Motor neurones that innervate distal and proximal musculature are mainly in __________ of the spinal cord, whereas those innervating the axial musculature _________
lumbar-sacral segments | occur at all levels
52
motor unit
alpha motor neurone + all the skeletal muscle fibres that it innervates; the smallest functional component of the motor system
53
motor neurone pool
collection of alpha motor neurones that innervate a single muscle
54
LMNs innervating axial muscles ____ to those innervating distal muscles
medial
55
LMNs innervating flexors _____ to those supplying extensors
dorsal
56
3 sources of input to an alpha motor neurone that regulate its activity are:
- central terminals of dorsal root ganglion cells whose axons innervate the muscle spindles - upper motor neurones (UMNs) in the motor cortex and brain stem - spinal interneurones
57
Slow-oxidative (Type I) Fibres: ATP derived from ______ _____ (slow/fast) contraction and relaxation _____ (βœ…/❌)fatigue resistant "______" because of high _____ content
``` oxidative phosphorylation slow βœ… "red meat" myoglobin ```
58
Fast (Type II) Fibres -- type IIa ATP derived from ______ _____ (slow/fast) contraction and relaxation _____ (βœ…/❌)fatigue resistant _____ (pale/red) and _____ (βœ…/❌) well vascularised
``` oxidative phosphorylation fast βœ… red βœ… ```
59
``` Fast (Type II) Fibres -- type IIx ATP derived from ______ _____ (slow/fast) contraction _____ (βœ…/❌)fatigue resistant _____ (pale/red) and _____ (βœ…/❌) well vascularised "______" ```
``` glycolysis fast ❌ pale ❌ white meat ```
60
origin
end of the muscle attached to the more stationary part of the skeleton
61
insertion
end attached to the skeletal part that moves
62
contractile response (twitch) has 3 parts:
lag -> contraction -> relaxation
63
twitch
when a muscle fibre is restimulated after complete relaxation, 2nd twitch = 1st twitch, magnitude-wise
64
twitch summation
when a muscle fibre is restimulated before complete relaxation and a 2nd twitch is added on to 1st
65
tetanus / tetanic πŸš’πŸ—»πŸ’₯
when a muscle fibre is stimulated so rapidly that it doesn't have an opportunity to relax at all between stimuli, a maximum sustained contraction occurs
66
For a muscle to shorten during contraction, the tension developed in the muscle must _____ the forces that oppose movement of the bone to which the muscle’s insertion is attached
exceed
67
example of load...
is the weight of the object being lifted
68
two primary types of contraction:
``` isotonic contraction (lift object) isometric contraction (hold object) ```
69
isotonic contraction = muscle tension _______ (changes/remains constant) and the muscle length _______ (changes/remains constant)
remains constant | changes
70
Isometric contraction: the muscle length _______ (changes/remains constant), so tension develops at ________ (increasing/constant) muscle length
remains constant | at constant muscle length
71
the two types of isotonic contractions are:
concentric | eccentric
72
concentric contraction
muscle shortens under load
73
eccentric contraction
muscle lengthens under load
74
Skeletal muscle can be attached to: - _____ - _____ (e.g. ______) - _____ (e.g. ______) - _____ - _____ (e.g. ______) - _____ (e.g. ______) - _____ - _____ ( [how?], e.g. ______)
Bone at each end crossing one joint (e.g. deltoid) crossing multiple joints (e.g. semimembranosus) Bone at one end and a different type of structure at the other (e.g. extraocular eye muscles) or nothing at the other (tongue) Itself (forming a circle; e.g. sphincter)
75
____ is a rigid structure capable of moving around a pivot point known as _____
lever | fulcrum (Krum z HP)
76
_____ function as levers, the _____ serve as fulcrums and the _____ provide the force to move the bones to produce directed movement
bones joints muscles
77
Levers can be used so that a small force can move a much bigger force i.e. ___________
mechanical advantage
78
There are four parts to a simple lever:
lever arm pivot effort load
79
there are 3 classes of levers:
``` class 1 lever class 2 lever class 3 lever ```
80
``` Class 1 lever ______----______----______ commonly known as "______" and "______" ___ (βœ…/❌) mechanical advantage e.g. _____ _____ (large/small) load _____ (large/small) range ```
``` effort pivot load β€œSee-saw”; β€œCrowbar” βœ… neck & head large & small, hence mechanical advantage ```
81
Class 2 lever ______----______----______ commonly known as "______" Effort force ______(>/
``` pivot load effort β€œWheelbarrow” < βœ… standing on the tippy toes ```
82
Class 3 lever ______----______----______ commonly known as "______" ___ (βœ…/❌) mechanical advantage, as effort ______(>//
``` pivot effort load β€œShovel” ❌ greater than larger and greater arm & forearm small & large, hence mechanical disadvantage ```
83
types of joints (6):
``` ball-and-socket joint (pectoral gridle + arm) pivot joint (elbow) saddle joint (wrist) ellipsoid joint (fingers) hinge joint (knee) plane joint (ankle) ```
84
joints that alter position during movement, which influences their β€œlever status” tend to ______ mechanical disadvantage, e.g. _____
minimise | knee
85
Synovial fluid in cavity --- 2 functions
lubricates the joint | provides nourishment for cartilage
86
Capsule & synovial membrane --- 2 functions
hold joint together | membrane makes synovial fluid
87
Articular cartilage ---- 2 functions
``` cushions impact (flexibility function) protects bone ```
88
intrinsic ligaments -- where?
part of capsule
89
extrinsic ligaments ---- where?
outside capsule | knee joint
90
ligaments ---- 2 functions
hold bones together, prevent unwanted movement
91
the myotatic reflex
when a skeletal muscle is pulled, it pulls back
92
Change in length (and rate of change) is registered by a sensory organ within the muscle, __________; this contributes to non-conscious ____________
the muscle spindle | proprioception
93
spindles consist of (4):
- a fibrous capsule - intrafusal muscle fibres - sensory afferents that innervate the intrafusal fibres - gamma motor neurone efferents that innervate the intrafusal fibres
94
describe sensory afferents
innervate the intrafusal fibres | Ia class, myelinated and very fast conducting
95
Striking of the _____ tendon with a ______ [item] causes a β€˜______’ [behaviour] underpinned by the _______ [type of reflex]
patellar tendon hammer knee jerk myotatic reflex
96
reflex [definition]
rapid, automatic response generated by the circuitry of the spinal cord
97
reflex [function]
- controlling automatic behaviour | - important role in voluntary movement
98
the myotatic reflex is a ___*___, the only one in humans | ___*___ is (2):
*monosynaptic reflex arc rapid most prominent in extensor muscles
99
the myotatic reflex can be used to assess...
the functional integrity of the spinal cord at specific levels
100
Muscle (joint) assessed: biceps (elbow) | Spinal level assessed: __
C5-C6
101
Muscle (joint) assessed: _____ | Spinal level assessed: C5-C6
supinator (wrist)
102
Muscle (joint) assessed: triceps (elbow) | Spinal level assessed: __
C7
103
Muscle (joint) assessed: ______ | Spinal level assessed: L3-L4
quadriceps (knee)
104
Muscle (joint) assessed: ____ | Spinal level assessed: S1
gastrocnemius (ankle)
105
intrafusal fibres can be subdivided on the basis of morphology and function into (1+2+1):
- Nuclear bag fibres - Bag 1 or dynamic - Bag 2 or static - Chain fibres
106
characteristics of bag 1 or dynamic
very sensitive to the rate of change of muscle length innervated by dynamic gamma motor neurones
107
characteristics of bag 2 or static
more sensitive to the absolute length of the muscle | innervated by static gamma motor neurones
108
characteristics of chain fibres
sensitive to the absolute length of the muscle | innervated by static gamma motor neurones
109
types of afferent fibre that innervate the intrafusal fibres (2): Both sets of afferents respond to stretch, but the _____ are more sensitive to _______ and _______ are more sensitive to _________
Ia afferents II fibres Ia fibres rate of change II fibres absolute length of the intrafusal fibres
110
afferent fibre that innervate the intrafusal fibres -- Ia afferents [description]
form a primary annulospiral nerve ending winding around the centre of all intrafusal fibres
111
afferent fibre that innervate the intrafusal fibres -- II fibres
are more slowly conducting, form flowerspray endings on all intrafusal fibres except the bag 1 dynamic type
112
RESPONSE TO SELECTIVE ACTIVATION OF STATIC AND DYNAMIC GAMMA MOTOR NEURONES -- Ia fibre
responds to both the rate of change of muscle length (dynamic response) and absolute length (steady state, or static response) of the muscle
113
RESPONSE TO SELECTIVE ACTIVATION OF STATIC AND DYNAMIC GAMMA MOTOR NEURONES -- Stimulation of static gamma fibre
causes steady state, or static response, to πŸ”Ό
114
RESPONSE TO SELECTIVE ACTIVATION OF STATIC AND DYNAMIC GAMMA MOTOR NEURONES -- Stimulation of dynamic gamma fibre
enhances the dynamic response to stretch
115
only static gamma motor neurones are active when...
an activity involves muscle length to change slowly and predictably
116
only dynamic gamma motor neurones are active during...
behaviours in which muscle length changes rapidly and unpredictably
117
free nerve endings location: characteristics:
location: found in capsule and connective tissue characteristics: most numerous HT [high threshold] & SA [slowly adapting] nociceptive function
118
Golgi-type endings location: characteristics:
location: only in ligaments HT [high threshold] & SA [slowly adapting] protective role?
119
Paciniform endings location: characteristics:
location: found in periosteum near the articular attachments and the fibrous part of the joint capsule characteristics: LT [low threshold] & SA [slowly adapting] acceleration detectors
120
Ruffini endings location: characteristics:
location: mainly in joint capsule characteristics: LT [low threshold] & SA [slowly adapting] static position and speed of movements
121
Proprioceptive information arises from (3):
- Muscle spindles - Golgi tendon organs - Joint receptors
122
Spinal interneurons receive input from (4):
- primary sensory axons (e.g. Ia and Ib fibres) - descending axons from the brain - collaterals (branches) of lower motor neurones - other interneurons
123
Inhibitory interneurons mediate:
- the inverse myotatic response | - reciprocal inhibition between extensor and flexor muscles
124
Excitatory interneurons mediate 2 reflexes:
the flexor reflex | the crossed extensor reflex
125
The flexor reflex | Noxious stimulus causes limb to flex by (2):
- contraction of flexor muscles via excitatory interneurones | - relaxation of extensor muscles via excitatory and inhibitory interneurones
126
Crossed extensor reflex Noxious stimulus causes limb to extend by (2): This reflex enhances postural support during withdrawal of a foot from a painful stimulus (you do not fall over!)
- contraction of extensor muscles via excitatory interneurones - relaxation of flexor muscles via excitatory and inhibitory interneurones
127
excitation-contraction coupling
the way in which the muscle converts an AP (electrical stimulus) into a contraction (mechanical response)
128
latent period
time delay between AP and muscle contraction

Biomedical Sciences BS22001 (4 decks)

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