Test 3 - 10/9 Lecture Flashcards
1
Q
Approximately ______ of body mass is attributed to skeletal muscle
A
40%
2
Q
_____ is the largest contributor to body weight and volume in non obese people
A
Skeletal muscle
3
Q
We use skeletal muscles for (3 things mentioned in class)
A
communication
body temp regulation
storage of glycogen
4
Q
Skeletal muscles are _____ of the CNS
A
“Effectors”/neural targets
5
Q
Skeletal muscles store energy as
A
Glycogen (lots of sugar molecules stuck together)
6
Q
Where else in the body do we have large amounts of glycogen storage (other than skeletal muscles)
A
Liver
7
Q
Ligaments connect (typically)
A
bone to bone
8
Q
3 examples of ligaments
A
patellar/ACL/MCL
9
Q
Tendons typically connect ______ to ______. Sometimes they can connect _____ to _____ via _____
A
muscle to bone
muscle to muscle
Intermediate
10
Q
One example of a tendon
A
Achilles
11
Q
A muscle cell is called
A
muscle fiber
12
Q
A group of skeletal muscle cells
A
Fasciculus
13
Q
A group of fasciculi make up a
A
muscle
14
Q
The cylinders that make up muscle fibers are
A
Myofibrils
15
Q
________ contain the contractile proteins (actin and myosin) of the muscle
A
myofibrils
16
Q
We typically have ________ myofibrils per muscle fiber. If we have a larger muscle we could have _____ myofibrils
A
200+
Thousands
17
Q
What is an example of when we would see fewer myofibrils
A
fine motor control.
18
Q
The functional unit of a myofibril
A
sarcomere
19
Q
Between two Z disks we have
A
A sarcomere
20
Q
A motor unit is
A
A collection of one of more muscle cells (fibers) that are controlled by a single motor neuron.
21
Q
How many skeletal muscle cells do motor neurons control?
A
can control just 1 or many
22
Q
Fine motor control utilizes a ______ (small/large) motor unit
A
Small motor unit
23
Q
It is easier to activate a ______ motor neuron. Activating a _______ motor neuron requires more energy
A
Small; large
24
Q
Skeletal muscle is classified by the following names
A
Type 1 (Red/Slow) and Type 2 (White/Fast)
25
Type 1 skeletal muscle
Red muscle. slow twitch, lots of myoglobin and lots of mitochondria capable of long sustained work.
26
Why is myoglobin significant in skeletal muscles
its an iron containing protein that helps O2 unload from the blood into the muscle to the mitochondria to give us ATP
27
Why is there a red color in type 1 skeletal muscles
because of the amount of myoglobin
28
Type 2 skeletal muscle
White muscle. fast twitch, very little myoglobin, and less mitochondria. They are capable of high intensity shortly sustained work.
29
A bird that migrates of thousands of miles will have a breast muscle that is made of
Red (dark) meat, Type 1 muscle (slow)
30
On the island of Kauai there are many chickens that will fly a short distance onto your table and steal your food. Their breast muscle is made up of.
White meat, Type 2 muscle (fast)
31
The soleus muscle of the leg helps support your weight while standing without tiring. This is an example of
Type 1/Red/slow muscle fibers
32
The ocular muscle responds quickly and does not require stamina. This is an example of
Type 2/white/Fast muscle
33
The vast majority of your muscles are not easily separated into ________ an example being the gastrocnemius
Type 1 vs Type 2 fibers
34
The cell wall of a muscle cell is called the
sarcolemna
35
The fluid within the muscle cell is called the
Sarcoplasm
36
Specialized endoplasmic reticulum in muscle cells
Sarcoplasmic reticulum
37
Sarcoplasmic reticulum is located
in proximity to the cell wall or the transverse tubules
38
______ run perpendicular to allow AP to penetrate deep into the muscle fibers
Transverse Tubules
39
The pattern/difference in color in skeletal muscles and cardiac muscles is called
Striation
40
Thick filament of muscle fiber
myosin
41
Thin filament of muscle fiber
actin
42
Actin that wraps circumferential around the sarcomere is called a
Z disk
43
There is one ________ on each end of the sarcomere
Z disk
44
The portion of the sarcomere that has only thin filaments is called
I band
45
The area of a sarcomere that has only myosin is called
H band/H zone
46
The portion of the sarcomere with overlap of thick and thin filaments is called the
A band
47
The border between two neighboring sarcomeres
Z disk
48
Stretchy connective tissue that fastens the subunits of the sarcomere in place
Titin
49
In the myofibrils we would expect to see many _______ to provide energy so that work can be done
mitochondria
50
During a muscle contraction the portion of the sarcomere that doesn't change length is the
A band (portion with actin AND myosin)
51
During a muscle contraction the I band ______, the H band _____ and the Z disks _______
Shrinks; disappears; move closer together
52
the process of a shortening sarcomere is called
The sliding filament mechanism
53
The individual muscle fibers in a skeletal muscle span
From one tendon to the next (some can be very long)
54
Skeletal muscle cells have mutliple
nuclei
55
How do long neurons get proteins from the nucleus to the other end of the neuron?
Train track system. Load up the proteins and boot scoot and boogie it on down.
56
Myosin filaments are long _____ of myosin molecules that are _________
strings
wrapped together at the tail
57
There are _____ myosin molecules that make up each myosin filament
~200
58
Each myosin molecule is made up of ______
6 chains
59
Describe the 6 chains of the myosin molecule
2 heavy chains wrapped around each other in a spiral that make up the myosin tail and 2 sets of light chains on either side of the head.
60
The essential light chains are located
on the periphery of the head of myosin
61
The two regulatory light chains are located
deep to the essential chains on the myosin head.
62
What is the difference in regulatory light chains in skeletal muscle vs smooth muscle
Skeletal muscle: don't really do much for skeletal muscle
Smooth muscle: phosphorylation of the myosin heads
63
Actin is made up of _______ strands called ______
2 strands called F-actin and tropomysin
64
The myosin heads have an affinity to bind to
The active sites on actin
65
The active sites of actin are located on
The F-actin strand
66
Tropomyosin _______ the binding of F-Actin and tropomyosin
Inhibits/blocks
67
The _______ helps displace tropomyosin to expose the active site of F-actin
Troponin complex
68
The troponin complex is made up of 3 protein subunits labeled
I, T, and C
69
the I subunit of troponin connects to ______ the T subunit of troponin connects to ______ and the C subunit of troponin connects to ______
Actin-F; Tropomyosin; 4 calcium molecules and subunit I and T.
70
When activated the subunit C on the troponin complex does what?
Twists/manipulates the other two subunits I and T; displacing tropomyosin and exposing the active sites of F-Actin
71
A myosin that is in the "ready" state is typically bound to
ADP and a phosphate
72
Re-setting a myosin head that has contracted requires
ATP
73
How should the myosin heads look in a skeletal muscle that is entirely healthy and is resting?
Cocked and ready to go with ADP and phosphate attached
74
A myosin is ready to attach to an F-Actin active site. What is bound to the head and what happens throughout the contraction?
A ready myosin head is attached to ADP and a phosphate. When the head binds to the active site these are still connected. When it is time to contract, the phosphate is removed and the energy released from the dephosphorylation allows the head to "pull" on the actin.. This shortens the sarcomere. After the work has been done ADP falls off of the molecule that then needs ATP to reset and release from actin
75
What is the reason rigor mortis sets in?
We need ATP to detach a contracted myosin head from actin. Without ATP, in such a case as cardiac death, the muscles are stuck in this contracted state that makes them stiff.
76
What is the excitation-contraction coupling?
Starts off as end plate potential, turning into an AP, the AP liberates Ca from its storage areas inside the cell
77
Where do we have DHP voltage sensors?
high density in our T tubules.
cell wall
78
There is a physical coupling (latch mechanism) between the _____ and the ______ that releases Ca
DHP voltage sensor
Sarcoplasmic reticulum
79
An exaggeratedly overstretched sarcomere cannot produce force. Why?
There is no overlap of actin and myosin and therefore they cannot interact.
80
The optimal length for a sarcomere is approximately
2 micrometers
81
A sarcomere that is already fully contracted has an action potential pass through it. What happens?
There is no force produced. The muscle cannot get any shorter
82
Skeletal muscles need to be _______ to perform efficiently
stretched (optimally)
83
An example of a muscle that is not optimally stretched at rest is ______
The heart
84
A tendon that has been torn and then surgically repaired is likely _____ than it was before. Meaning the muscle that it is attached to is likely ______
Shorter; Overstretched
85
The Length-tension relationship of the heart is called
Frank Starlings Law
86
Tension developed by a contraction is called
Active Tension
87
Define passive tension
The force that is utilized when stretching a muscle that is at rest.
88
Active tension + Passive tension =
Total tension
89
What happens in the heart when the sacromere gets overstretched?
Less force produced in L ventricle –> Heart failure
