Skeletal & Muscular Systems Flashcards

1
Q

2 components of the skeleton:

A

cartilage and bone

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2
Q

cartilage

A
  • type of CT that is softer and more flexible than bone

- chondrocytes are cells responsible for synthesizing cartilage

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3
Q

bone

A

-mineralized CT that can withstand physical stress

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4
Q

compact bone

A

-dense bone composed of structural units called osteons

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5
Q

structure of an osteon

A

-central microscopic channel called a Haversian Haversian canal surrounded by a number of concentric circles called lamellae

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6
Q

spongy bone

A
  • less dense, consists of bony spicules (trabeculae)

- cavities b/w spicules filled with red (blood cell formation) or yellow bone marrow (infiltrated by adipose tissue)

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7
Q

osteoblasts

A
  • synthesize new bone

- mature into osteocytes

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8
Q

osteoclasts

A

-bone is broken down and released into the blood

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9
Q

endochondral ossification

A
  • existing cartilage is replaced by bone

- typically long bones

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10
Q

intramembranous ossification

A

-CT is transformed into and replaced by bone

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11
Q

pyramidal system

A

-provides rapid motor commands (voluntary) to skeletal muscle and other organs

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12
Q

extrapyramidal system

A

-somatic motor commands as a result of processing performed at the involuntary level

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13
Q

skeletal muscle

A
  • responsible for voluntary movement and is innervated by the somatic nervous system
  • striated
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14
Q

myofibrils

A

-embedded in the fibers, further divided into contractile units called sarcomeres

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15
Q

sarcoplasmic reticulum

A

-modified ER that envelopes myofibrils and stores calcium ions

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16
Q

sarcolemma

A
  • cell membrane of a muscle fiber

- propagates an action potential and is connected to a system of transverse tubules

17
Q

T system

A

-provides a channel for ion flow throughout the muscle fibers

18
Q

sarcomeres

A

-composed of thin (actin) and thick (myosin) filaments

19
Q

Z line

A

defines boundaries of a single sarcomere

20
Q

M line

A

runs down the center of the sarcomere

21
Q

I band

A

contains thin filaments only

22
Q

H zone

A

contains thick filaments only

23
Q

A band

A

spans the entire length of the thick filaments and any overlapping portions of thin filaments

24
Q

neuromuscular junction

A

link b/w the nerve terminal and the sarcolemma of the muscle fiber

25
contraction
- once an action potential is generated, it is conducted along the sarcolemma and the T system into muscle fibers - sarcoplasmic reticulum release calcium ions which bind to troponin C and initiates contraction
26
rigor mortis
several hours after death, all the muscles in the body contract and go rigid b/c of the absence of ATP
27
isotonic contractions
muscle shortens against a fixed load while tension remains constant
28
dynamic contraction
change in the length of the muscle with a corresponding change in tension
29
concentric contraction
type of dynamic concentration where the muscle fibers shorten and tension increases
30
eccentric contraction
type of dynamic contraction where muscle fibers lengthen and tension increases
31
isometric contraction
when both ends of the muscle are fixed and no change in length occurs, but tension increases
32
simple twitch
- response of a single muscle fiber to a brief stimulus at or above the threshold stimulus - consists of a latent period, contraction period, and relaxation period (absolute refractory period)
33
temporal summation
-when fibers of a muscle are exposed to frequent stimuli, muscle cannot fully relax and contractions combine to become stronger and more prolonged
34
tetanus contraction
- contractions become continuous when the stimuli are so frequent that the muscle cannot relax - stronger than a simple twitch
35
tonus
- state or partial contraction | - muscles are never completely relaxed
36
Cori cycle
-during strenuous activity, skeletal muscles convert lactic acid into glucose
37
smooth muscle
- involuntary actions - innervated by ANS - lack striations, posses one nucleus
38
cardiac muscle
-heart muscle -striated -one or two nuclei involuntary, ANS
39
energy reserves
- creatine phosphate: in vertebrates, energy is temporarily stored in this compound - myoglobin: maintains oxygen supply in muscles by binding oxygen tightly