Physiology Flashcards
(117 cards)
1
Q
what are muscle striations formed from
A
alternating dark and light filaments
2
Q
what are the dark filamens
A
thick myosin
3
Q
what are the light filaments
A
thin actin
4
Q
what is contained in the sarcomere
A
actin and myosin
5
Q
are gap junctions present in skeletal muscle
A
no
6
Q
define motor unit
A
a single alpha motor neurone and the fibres it innervates
7
Q
why would a motor neurone contain few fibres per motor unit
A
when precision is more important than power
8
Q
give an example of a muscle where there are few fibres per motor unit
A
extra-ocular muscles
9
Q
give an example of a muscle where there are many fibres per motor unit
A
quads
10
Q
give the structure of muscle
A
Muscle -> muscle fibre -> myofibril -> sarcomere
11
Q
how big is a muscle fibre
A
1 cell
12
Q
what is a myofibril
A
intracellular contractile structure
13
Q
what is a functional unit
A
smallest component that can perform all an organ’s functions
14
Q
what is the functional unit of skeletal muscle
A
sarcomere
15
Q
names of the zones within a sarcomere
A
A band
H zone
M line
I band
16
Q
what is the A band
A
thin filament overlapping both ends of thick filaments
17
Q
what is the H zone
A
lighter area within A-band where thin filaments don’t reach
18
Q
what is the M line
A
vertically down middle of A band in centre of H zone
19
Q
what is the I band
A
remaining portion of thin filaments
20
Q
how to histologically tell apart muscle fibre types
A
succinate dehydrogenase stain
21
Q
names of skeletal muscle fibre types
A
Slow oxidative I
Fast oxidative IIa
Fast glycolytic IIx
22
Q
features of type I skeletal muscle
A
resistant, oxidative metabolism, > mitochondria
23
Q
when is type I skeletal muscle used
A
long low aerobic activities - walking, posture
24
Q
features of type IIa skeletal muscle
A
intermediate twitch, aerobic & anaerobic metabolism, fatigue resistant
25
when is type IIa skeletal muscle used
long moderate work - jogging
26
features of type IIx skeletal muscle
fast twitch, anaerobic metabolism, fatigue easy, < mitochondria, greater force, white fibre
27
when is type IIx skeletal muscle used
short term high intensity e.g. jumping
28
what does skeletal muscle look like on histology
unbranched nuclei under sarcolemma, multinucleate (syncytium), long cylindrical fibres
29
where are the nuclei located in the cell in skeletal muscle? how does the differ from cardiac muscle?
peripherally, in centre in cardiac
30
define fascicle
bundle of muscle fibres
31
define epimysium
connective tissue that surrounds muscle
32
define perimysium
connective tissue around a single fascicle
33
define endomysium
connective tissue around a single muscle fibre
34
sarcomes entend from ...
1 Z line to the next
35
sliding filament theory; where is Ca released from
sarcoplasmic reticulum lateral sac
36
sliding filament theory; what does Ca bind to
troponin on actin
37
sliding filament theory; what is the power stroke
tropomyosin moved aside; pulls thin filament inward during contraction to reveal cross bridge
38
sliding filament theory; what happens when no action potential
ATP pumps Ca++ to sarcoplasmic reticulum
39
sliding filament theory; what is required for AP
ATP
40
sliding filament theory; what happens when muscle muscle
no cross bridge binding, actin physically covered by troponin tropomyosin complex
41
what factors influence muscle tension
no. of fibres contracting (motor unit recruitment >1 unit contracting, prevents fatigue)
tension developed by each fibre (stimulation freq & fibre length/thickness)
42
what happens if repetitive fast stimulation
twitches summate
43
what happens in tetanus
sustained contraction; stimulated so rapidly muscle doesn’t relax between stimuli stronger contraction
44
why doesn't tetanus happen in cardiac muscle
long refractory period
45
when is maximum tension in skeletal muscle
at optimum (resting) muscle length before contraction
46
what movements are done by isotonic contraction
movement/moving objects
47
what movements are done by isometric contraction
supporting objects/posture
48
what happens in isotonic contraction
tension constant as muscle length changes
49
what happens in isometric contraction
tension develops at constant muscle length
50
are there different types of fibre in each motor unit
nope
51
what differences are there between skeletal muscle fibres
enzymatic ATP synthesis pathways, fatigue resistance, myosin ATPase activity
52
what does myosin ATPase activity affect
muscle contraction speed
53
where does fast ATP supply for muscle contraction come from
creatine phosphate to ADP
54
where does ATP supply for muscle contraction come from when O2 present
oxidative phosphorylation
55
where does ATP supply for muscle contraction come from when O2 not present
glycolysis
56
what is a reflex action
stereotyped response to a specific stimulus
57
what type of feedback is the stretch reflex
ve feedback mechanism
58
when is the stretch reflex used
maintains posture
59
what is the stretch reflex
simplest monosynaptic spinal reflex resisting passive change in muscle length
60
what is a muscle spindle
sensory stretch reflex receptors
61
what is a muscle spindle formed of
specialised intrafusal fibres
62
nerve supply to muscle spindle
have own efferent nerve supply, gamma motor neurones
63
where do muscle spindles synpase
in spinal cord with alpha motor neurons
64
how can you test the muscle spindle
patellar tendon tap
65
what type of neuro-receptor is involved in synaptic transmission of skeletal muscles
nicotinic ACh GPCR
66
what terminates synaptic transmission in skeletal muscle
ACh hydrolysis by AChE
67
when does the e.p.p. occur and what effect does this have
when na influx > k efflux causes depolarisation
68
when is an AP stimulated in skeletal muscle
when e.p.p. is > threshold
69
what is the m.e.p.p
response to 1 quantum of neurotransmitter
70
what is haemopoiesis and where does it take place
BC production in bone
71
what is an osteocyte
mature osteoblast bone cell
72
where are osteocytes
in canaliculi/lacunae in bone matrix
73
what is an osteoblast
bone forming cells with prominent mitochondria
74
where are osteoblasts
on bone surface
75
what is an osteoclast
bone resorption multinucleate cell
76
where are osteoclasts
on surface
77
what is a osteoprogenitor cell
stem cell; pool of reserve osteoblasts
78
where are osteoprogenitor cells
on bone surface under periosteum
79
how do osteocytes recieve oxygen and nutrients
from synovial fluid via haversian canals
80
what cell type are osteoclasts derived from
macrophages
81
which type of bone is strong: woven or lamellar
woven weak
| fibrous lamellar strong
82
what is NADH oxidised to
NAD+ + H+ + 2e-
83
which types of collagen are in hyaline and fibrocartilage
type 1 collagen hyaline
| type 2 collagen fibrocartilage
84
which cells produce synovial fluid
fibroblasts
85
what is found in the centre of bone
bone marrow
86
what type of bone surrounds bone marrow
cancellous trabecular spongy bone
87
what type of bone is located externally
compact cortical lamellar bone
88
what type of stain is used for bone
silver
89
what is another name for osteon
haversian system
90
what are osteon
cylindrical tubes within bone containing the haversian canal
91
what is contained within the haversian cnaal
arterial and venous branch, nerve fibres and osteogenic cells
92
what structure runs perpendicularly in bone and what is its function
canaliculi connect osteocytes to one another & to Haversian canal
93
what is lacunae of bone
space containing osteocytes
94
how do osteocytes of cancellous trabecular bone survive
from contact to adjacent marrow cavity
95
what is the structure of lamellar fibrous bone
collagen fibres orientated in the same direction
96
what is a diarthrosis
synovial joint
97
what type of joint are the intervertebral discs
cartilaginous
98
what type of cartilage is found on articular surfaces
hyaline
99
what type of joint is the pubic synthesis
cartilaginous
100
what type of cartilage are the tracheal rings
hyaline
101
what is fibrocartilage formed of
type 1 collagen + chondrocytes
102
what type of joint is the chostochondral joint and what type of cartilage are the costal cartilages
cartilaginous joint
| hyaline cartilage
103
what is a chondroblast
immature chondrocyte
104
what cells secrete collagen
chondrocytes
105
what is cartilage regenerated to
fibrocartilage
106
what are the most successful joint replacements
hip and knee
107
give 3 examples of toxins produced by staph aureus
enterotoxin
staphylococcus scaled skin syndrome SSSST
panton valentine leukocydin PVL
108
what type of infection do sessile bacteria cause
biofilms
109
name 3 types of cartilage
hyaline
elastic
fibrocartilage
110
what is perichondrium
fibrous connective tissue layer directly above cartilage surface
111
what are the 3 types of joints
synovial
fibrous
cartilaginous
112
what is the difference between a simple and a compound synovial joint
simple: 1 articular surface pair
compoound: >1
113
what mineral is found in highest quantities in bone
ca hydroxyapatite crystal
114
what is the diaphysis, physis, metaphysis and epiphysis of long bones
diaphysis shaft, growth plate physis, metaphysis around physis, epiphysis on physis
115
where does central tolerance take place
primary lymphoid tissue
116
what cells express HLA class I on their surface
all nucleated cells
117
what cells express HLA class II on their surface
specialised APCs
