1
Q
Red fibers ( slow twitch) v. White fibers ( fast twitch)
A
Red fibers are for more sustained contractions and has more mitochondria to carry out oxidative phosphorolaytion and more myoglobin ( carries O2 via heme prosthetic group).
White fibers has less mitochondria and myoglobin. Responsible for fast movements.
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2
Q
Tonus
A
Sustained rhythmic contraction of smooth muscle.
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3
Q
Myogenic activity
A
Contraction without nervous system innervation. Seen in smooth muscle.
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4
Q
What makes cardiac muscle different from skeletal and smooth muscle?
A
Cardiac muscle has properties of both smooth ( innervation via autonomic NS and fire rhythmically) and skeletal muscle ( appears striated under the microscope).
Heart fires rhythmically via intercalated disks; made of desmosomes which prevents cells from separation during the contraction and gap junctions which allows for the cells to fire rhythmically.
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5
Q
How many nuclei does each muscle type contains?
A
Skeletal has many nuclei.
Cardiac has 1-2 nuclei
smooth is uninucleated.
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6
Q
Describe the fibers of each muscle type
A
Skeletal muscle and smooth muscle are bunched while cardiac fibers are branched.
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7
Q
Which muscle types contains gap junctions?
A
Smooth and cardiac muscle.
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8
Q
What components of the nervous system control each of the muscle fibers?
A
Skeletal muscle is controlled the somatic NS ( voluntary control)
Cardiac and smooth muscle are controlled by the autonomic NS ( involuntary control).
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9
Q
Striated muscle
A
Muscle that appears stripped ( sacromeres) under the microscope.
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10
Q
Role of titin in the sacromere
A
anchors actin and myosin together and prevents overstretching.
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11
Q
Define each of the zones and bands of the sacromere?
A
Z-line - represents the boundary of the sacromere.
M-line- line that runs down the center of the sacromere.
I band- represents thin actin
H band- represents thick myosin
A band- the overlap of the I and H bands.
During contraction the myosin pulls towards of the sacromere decreasing the sacromere. This causes a decrease in the I and H bands but NOT the A band.
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12
Q
Describe how calcium is released for muscle contraction?
A
- Ach binds to ligand gated channels on the sacrolemma.
2.Depolarization cause Na+ to rush in and cause an action potential that propagates down the T-tubules to the sacroplasmic reticulum causing the release of calcium down it’s concentration gradient.
- Calcium binds to tropinin causing a change in tropomyosin and exposing the myosin- binding sites on actin that allows myosin heads to bind to the actin.
- When depolarizing stimulus is stopped calcium is actively transported back into sacroplasmic reticulum causing the muscle to go back in a resting state.
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13
Q
What is the functional unit of cardiac and skeletal muscle?
A
The sacromere
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14
Q
Sacromeres attached to each in end to end are called what? What are a collection of sacromeres composed of?
A
Myofibrils
A bunch of sacromeres are called myocytes.
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15
Q
Where does the the nervous system acts on muscle?
A
The neuromuscular junction ( also called the motor end plate).
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16
Q
Simple twitch
A
The contraction of a single muscle fiber. Includes the latent period ( release of calcium from sacroplasmic reticulum), contraction period, and relaxation period.
17
Q
Tetanus
A
When constant stimulation doesn’t allow the muscle to rest.
18
Q
Describe the sliding filament model
A
Describes how are muscles contracts
- When fiber is at rest in a high energy conformation ATP is hydrolyzed ( ADP +Pi) on the myosin head. Calcium binds to troponin causing a conformation change in tropomyosin exposing myosin head.
- The myosin head binds to the actin filament.
- The dissociation of Pi provides the power stroke where the length of the sacromere decreases.
- ADP is released from the myosin head. Myosin head is in a low energy state.
- ATP then binds and breaks apart the cross- bridge link.
6.Hydrolysis of ATP brings it back into the resting, high energy, state.
- Happens again until calcium is taken back up into the sacroplasmic reticulum
19
Q
What does the muscles use as energy reserves?
A
Use of creatine- detach phosphate from ATP and add it to creatine, in times of stress the processed is reversed to make the ATP.
Use of myoglobin and increased oxygen delivery to the muscles.
20
Q
Oxygen debt
A
The amount of oxygen needed by the muscles and the amount of oxygen present in the muscles.
21
Q
What are the two types of skeletons?
A
Endoskeleton is when the skeleton is inside the body.
Exoskeleton is when skeleton encases the organism ( think insects).
22
Q
Slow twitch ( type 1) oxidative fibers
A
Contract at a slower rate and is more resistance to fatigue.
Uses aerobic respiration to generate ATP and so has a lot of mitochondria, myoglobin, and an extensive capillary network.
23
Q
Describe fast glycolytic fibers ( 2X) and fast oxidative glycolytic fibers ( 2A)
A
Fast glycolytic fibers ( 2X) primarily uses anaerobic respiration for energy and so produces more H+ and fatigues easily as a result.
Fast oxidative glycolytic ( type 2A) fibers has intermediate fatigue and uses both aerobic and anaerobic respiration.
24
Q
Where does bone strength comes from?
A
Compact bone
25
Q
Describe spongy bone
A
Contains trabeculae ( responsible for the sponge properties) in-between trabeculae is cavities that contains two types of bone marrow:
Red marrow- composed of hom*opoietic stem cells which are capable of differentiating into any cell type in the body.
Yellow marrow- contains fat cells and are inactive.
26
Q
Describe the structure of long bones.
A
A long cylindrical section called the diaphysis which leads to a spread out section called the metaphysis and terminates at the epiphysis.
The epiphysis contains epiphyseal growth plates which contains mitotic stem cells. These plates are open until puberty.
Outside of the diaphysis contains periosteum which serves as sight of attachement for muscle.
27
Q
Tendons v. Ligaments
A
Tendons attaches muscle to bone while ligaments attaches bone to bone via joints.
28
Q
What are the two cell types involved in building and maintaining bone?
A
- Osteoclasts - resorbs bone ( breaks it down)
- Osteoblasts - builds bone.
- Both are needed in maintaining bone*h
29
Q
What are the roles of calcitonin and PTH in bone formation/ resorption?
A
Calcitonin works to decrease blood calcium levels by increasing bone formation.
PTH works to increase blood calcium levels by increasing bone resorption.
30
Q
What is cartilage composed of?
A
Composed of chondrin which consists of chondrocytes. It’s avascular and not innervated.
31
Q
What are the ways to create bone?
A
- Endochondral ossification - creating bone by the hardening of cartilage.
*Intramembranous ossification- creation of bone via embryonic connective tissue.
32
Q
What are the 2 types of joints?
A
Movable joints- you can move them ( ie. hinge joints, ball and socket)
Immovable joints- create fused bones called sutures ( ie. the skull).
33
Q
Synovial capsule
A
Encloses joint cavity and secretes synovial fluid which serves to lubricate the joint.
34
Q
Articular cartilage
A
Coats the articular surfaces and lubricates them so they can withstand impact better.
35
Q
Origin v. Insertion
A
The origin is the part of muscle with larger bone attachment. The insertion is the part of the bone where there is less muscle attached.
Muscles can work in antagonistic or synergistic pairs.
36
Q
Flexor v. Extensor
A
Flexor movement that decreases the angle across a joint.
Extensor is movement that increases the angle across a joint.
37
Q
Abductor v. Adductor
A
Abductor is the movement of a limb away from the midline.
Adductor is the movement of a limb toward the midline.
38
Q
Medial rotation v. lateral rotation
A
Medial rotation is the rotation of the axis of the limb away from the midline.
Lateral rotation is the rotation of the axis of the limb toward the midline.
