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Biology > Ch 11 - Musculoskeletal System > Flashcards

Ch 11 - Musculoskeletal System Flashcards

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1
Q

Contraction of what kind of muscle compresses venous and lymphatic systems ?

A

Skeletal muscle

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2
Q

What are sarcomeres?

A

Arrangements of actin and myosin in repeating units - appears striated when viewed microscopically

(in skeletal muscle)

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3
Q

Is skeletal muscle UNI or MULTI nucleated?

A

MULTI!

Because muscle cells dude in long rods during development

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4
Q

Fibers within skeletal muscle:

5

A

Red fibers
“Slow-twitch” fibers
Contract slowly but last longer (or posture)
High myoglobin content

White fibers 
   "Fast-twitch" fibers
   Contract quickly but fatigue quickly
   Contain less myoglobin
   (Hence less iron, light color)
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5
Q

What is myoglobin?

A

An oxygen carrier that uses iron in a heme group to bond to oxygen (imparting a red color)

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6
Q

How is smooth muscle nucleated?

A

Has one nucleus in the middle of the cell

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7
Q

What is tonus?

A

A constant state of-low level contraction, in smooth muscle (ie vessel walls).

Smooth muscle is capable of more SUSTAINED contractions than skeletal muscle

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8
Q

What is my myogenic activity?

A

Muscle that an contract without input from the nervous system

In smooth muscle, the muscle cells can respond directly to stretch or other stimuli

In cardiac muscle, cells are able to define and maintain their own rhythm.

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9
Q

What kind of nucleation does cardiac muscle have?!

A

Mostly uni-nucleated but some cells have two nuclei

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10
Q

How are cardiac muscle cells connected?

A

Intercalated discs which have many gap junctions (allows flow of ions directly between cells)

*this is key for depolarization and contraction of cardiac muscle

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11
Q

What three biological systems play a role in the contraction of cardiac muscle?

A

Musculoskeletal (obv)

Nervous - vagus nerve (parasympathetic) to slow the heart down

Endocrine - norepinephrine (sympathetic neurons) or epinephrine can increase heart rate and contractility

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12
Q

How does EPINEPHRINE act on cardiac muscle?

A

Increases intracelullar calcium levels within the myocytes (contractions rely on calcium)

Results in increased heard rate and greater contractility

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13
Q

Thick versus thin fibers: what proteins are in each?

A

Thick - MYOSIN

Thin - ACTIN, troponin, tropomyosin

Troponin and tropomyosin help regulate the interactions between actin and myosin filaments.

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14
Q

Lines if the sarcomeres zones:

A

Z line: the end of the sarcomere

M line: runs in the middle

I-band: area of only thin filaments

H-zone: area of only thick filaments

A-band: thick filaments in their entirety (incl overlap with thin filaments)

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15
Q

How do lines in the sarcomeres change during contraction?

A

H-zone, I-band, Z lines and M-lines become shorter (closer together)

HIZM

The A - band stays the same (the actins get smaller but the myosin don’t change length during contraction)

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16
Q

What is a myofibril?

A

Made up of sarcomeres end to end

Surrounded by the sarcoplasmic reticulum (modified ER) that has a HIGH CONCENTRATION OF CALCIUM IONS

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17
Q

What are he sarcoplasm and sarcolemma ?

A

Sarcoplasm: modified cytoplasm just outside the sarcoplasmic reticulum

Sarcolemma: the cell membrane of a myocyte

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18
Q

What is the role of the SARCOLEMMA?

How do T-tubules relate to the sarcolemma?

A

It can propagate action potentials

Can spread the action potential to all sarcomeres in a muscle through the use of transverse tubules (T-tubules) that are oriented perpendicularly to the myofibrils.

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19
Q

What is rhabdomyolysis ?

A

Physical trauma (compression) that destroys skeletal muscle tissue

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20
Q

What is rigor mortis?

A

ATP production stops after death

There is no ATP to bind with myosin and release the actin filament, so the muscle cannot relax and lengthen.

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21
Q

What is a simple twitch?

A

A SINGLE muscle fiber responding to stimulus at threshold.

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22
Q

What is the latent period?

What happens during this time?

A

The time between reaching threshold and the onset of contraction.

During this time, action potential spreads along the muscle and allows calcium to be release from the SR

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23
Q

What does summation if frequent simple twitches lead to?

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A

The contractions can combine and become stronger and more prolonged, without sufficient time to relax.

This is called FREQUENCY SUMMATION and if there is no time at all to relax, leads to TETANUS

24
Q

What is tetanus?

Disease versus physiological condition

What causes it?

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A 
Disease:
Caused by clostridium tetani
Release a toxin, tetanospasmin
Blocks the release of GABA which inhibits motor neurons - hence motor neurons are overly excitable
Leads to constant contractions

Physiological condition:
Muscle contraction unable to relax
Results in muscle fatigue
Can result from simple twitches in succession

25
How do red (slow-twitch) muscle fibers make ATP?
They have LOTS of mitochondria, and use oxidative phosphorylation to MAKE ATP.
26
What is creatine phosphate?
A supplemental energy reserve Transferring of a phosphate group to creatine during times of rest - reverse the reaction to generate ATP as needed! Creatine + ATP ADP + cr. phosph
27
How do white (fast-twitch) fibers make ATP?
They have a lot less mitochondria - rely on GLYCOLYSIS and FERMENTATION to make ATP
28
What happens when muscles use ANAEROBIC metabolism to make energy?
The muscles need more oxygen that they are reviving! (Oxygen debt) Lactic acid is produced Lactic acid accumulation fatigues he muscle After exercise, the body converts lactic acid back to pyruvate which can then enter the citric acid cycle. (This requires more oxygen!)
29
What is oxygen debt?
The amount of oxygen needed by the muscle versus the actual amount present The "debt" is the difference the body has to make up AFTER strenuous exercise.
30
What is the axial skeleton? What bones does it include?
The basic central framework of the skeleton ``` 1. Skull Cranium Mandible 2. Vertebral column Vertebrae (C, T, L) Sacrum Coccyx 3. Ribcage 4. Hyoid bone (swallowing) ```
31
What is the appendicular skeleton? What bones does it include?
The "outer" bones - mostly long bones Bones of the limbs Pectoral girdle (scapula, clavicle) Pelvis
32
How many bones in the body?
206 💃💃
33
Where is bone marrow found? Red versus yellow bone marrow
In the trabeculae RED: Hematopoietic stem cells (make all the cells in the body) YELLOW: Primarily made up of fat, enter ally inactive
34
Structure of long bones:
Diaphysis - the long middle part Metaphysis - the neck Epiphysis - the ball end The inside of the diaphysis and metaphysis is cancellous bone, and the outermost portions are compact bone
35
What is the epiphysial (growth) plate?
A cartilaginous structure at the inner edge of the epiphysis of long bones Prior to adulthood, it is filled with mitotic cells that contribute to growth. These plates close during puberty and vertical growth is halted.
36
Tendons versus ligaments
Tendons: attach muscles to bone Ligaments: hold bones together at joints
37
What is the bone matrix made of?
Organic components: - collagen - glycoproteins - other peptides Inorganic components: - calcium - phosphate - hydroxide ions
38
Haversian versus Volkmann canals
Haversian canals run parallel to patrons and parallel to the bone Volkmann canals run perpendicular to these (branch off Haversian canals) These canals contain blood vessels, nerve fibers, and lymph vessels
39
What is an osteon?
Structural unit of the bony matrix
40
What is lamellae?
Centric circles of bony matrix that surround the osteon/Haversian canal
41
What are lacunae?
Small spaces between the lamellae These house mature bone cells (ie osteocytes)
42
What are canaliculi?
Tiny hammers that connect lacunae and allow for the exchange of nutrients and wastes between osteocytes and the Haversian and Volkmann's channels
43
What nutrients are needed to build bone?
Osteoblasts use CALCIUM and PHOSPHATE from the blood to build bone. Osteoclastic activities releases calcium and phosphate back to the bloodstream
44
How does PARATHYROID hormone affect bone? | Also: role of vitamin D
Parathyroid hormone is release in response to LOW BLOOD CALCIUM It stimulates osteoclasts activity to release calcium and phosphate into the blood VITAMIN D is also activated by parathyroid hormone, and it also promotes bone resorption, though it also promoted the growth of new, stronger bone.
45
Hat role does calcitonin play in the bone / calcium levels?
Promotes bone formation (lowering blood calcium levels) Released in response to HIGH blood calcium levels
46
What is osteoporosis? What is thought to help prevent it?
Increased osteoclasts resorption and slower bone formation, which together result in loss of BONE MASS. Estrogen is thought to help prevent osteoporosis by stimulation osteoblastic activity
47
What is cartilage? How does it compare to bone?
Softer and more flexible than bone. Fetal skeletons are mostly made of cartilage - most adult bones come from the hardening of cartilage!
48
What are chondrocytes?
Cells of the cartilage's elastic matrix, which make CHONDRIN (the stuff that the magic contains)
49
Where is cartilage found in the adult body? | 5
1. External ear 2. Nose 3. Walls of larynx and trachea 4. Intervertebral discs 5. Joints
50
What is one MAJOR difference in the structure of bone versus cartilage?
Cartilage DOES NOT (for the most part) contain blood and lymph vessels, and is NOT innervated.
51
What is endochondral ossification ?
The hardening of cartilage into bone, which is responsible for the formation of most of the long bones in the body.
52
What is intramembranous ossification ?
Undifferentiated embryonic connective tissue (mesenchymal tissue) is transformed I to and replaced by bone. This happens in the bones if the SKULL
53
Immovable joints
Consist of bones that are fused together and make SUTURES EG, bones of the skull
54
Movable joints
Permit bones to shift relative to one another Joints (elbow, knew) Ball and socket joints (shoulder, hip) Etc
55
What is the stricture of a movable joint - what is it made up of?
``` Ligaments (bone to bone movement) Synovial capsule (enclosed joint) Joint cavity ``` ``` Synovium (soft tissue layer) Synovial fluid (lubricates movement) Articulate cartilage (coats the surface of the bones to absorb impact) ```
56
Origin versus insertion of muscle
ORIGIN: larger attachment to bone INSERTION: smaller portion of the muscle attached to bone
57
Synergistic versus antagonistic (pairs) or muscles
Synergistic: work together to achieve the same function Antagonistic: one relaxes while the other contracts. (Ie biceps and triceps)

Biology (11 decks)

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