Biology 9 (Muscular And Skeletal System)

Front 1

Skeletal Muscle

Back 1

- Voluntary and responds to conscious thought or stimulus
- Attached to bones by tendons
- Brings Bones Together

Front 2

What is the neurotransmitter of skeletal muscles?

Back 2

ACETYLCHOLINE!!!!

Front 3

How many neurons are muscles innervated by?

Back 3

ONNNEEEEEE!!! (for single muscle cell)

Front 4

Structure of Muscle

Back 4

Fasciles > Fibers > Myofibrils > Sarcomere > Thin/Thick Filaments

Front 5

Muscle Fibers

Back 5

- Multinucleated
- Single muscle cell
- Have "Sarcolemma" cell membrane (extra collagen)

Front 6

Myofibrils

Back 6

- Specalized
- Generates contraction
- Responsible for striated appearance
- Composed of MANY sarcomeres

Front 7

Sarcomere

Back 7

- Contain thin/thick filaments
- A sarcomere is everything inbetween the Z lines... also known as I band, H, band, A bands

Front 8

Thin Filaments

Back 8

Actin

Front 9

Thick Filaments

Back 9

Myosin

Front 10

A Band

Back 10

- Contains Thin AND thick filaments
- It's basically the I/H bands (but not including the Z band)

Front 11

H Band

Back 11

- ONLY thick filaments (myosin)

Front 12

I Band

Back 12

- ONLY thin filaments (actin)

Front 13

What is a contraction then?!

Back 13

- Z bands brought closer together
- Occurs when thin/thick filaments (I/H bands) slide over each other... they DON'T SHORTEN
- Myosin ATPAse energy source

Front 14

When does a contraction occur?

Back 14

When cytoplasmic Calcium Increases!!!!

Front 15

Steps of Contraction (4)

Back 15

1) Myosin head binds to binding site on actin (ATP+Pi)
2) "POWER STROKE", myosin head is in low energy state, pulls actin to center
3) ATP binds to release actin from myosin head
4) ATP hydrolysis, myosin now in high energy state

Front 16

Troponin-Tropomyosin Complex

Back 16

- Annoying thing on actin t hat prevents contraction when calcium is not present

Front 17

Troponin

Back 17

- Bound to Tropomyosin
- Binds Calcium
- When calcium binds, confirmational change to Tropomyosin so myosin can blind

Front 18

Neuromuscular Junction

Back 18

- ACETYLCHOLINE!
- Receives the impulses and releases calcium from the sarcoplasmic reticulum

Front 19

Myoglobin

Back 19

- Like hemoglobin, but specialized for muscles (only has 1 subunit)
- Reserves oxygen and releases when its needed

Front 20

So what happens when you have cramps?

Back 20

- Temporary exhaustion of energy supplies (ATP)
- Gotta get more.... stop workin out!

Front 21

So what is rigor mortis?

Back 21

- Complete ATP exhaustion
- Happens after death

Front 22

T-Tubules

Back 22

- What transmits the action potential between all the cells, also helps with transfer of materials

Front 23

What does Cardiac Muscle have that Skeletal Doesn't?

Back 23

- Intercalcatated disks
- Multinucleated
- Striated (thin/thick filaments)
- Not dependent on Motor Neuron stimulation (SA NODE does)
- Ach is INHIBITORY

Front 24

Smooth Muscle

Back 24

- Has no T-Tubules
- ONE nucleus
- No Striations
- Innervated by autonomic neurons (not by SA node, not dependent on motor neuron stimulations)

Front 25

What is the purpose of the skeletal system?

Back 25

- protect vital organs
- support body
- provide framework for movement
- store calcium and synthesize blood

Front 26

Fibroblast

Back 26

- Cell of the connective tissue
- Secrete collagen, make fat cells

Front 27

PTH

Back 27

- Stimulates osteoclast activity (clast destroys)
- Increase reabsorption of calcium (makes sense, we're destroying bone)

Front 28

Calcitonin

Back 28

- Inhibits osteoclast activity
- Decreases reabsorption of calcium

Front 29

Osteoblast

Back 29

Lays down collagen for bone formation

Front 30

Osteocyte

Back 30

Bone cells!

Front 31

Osteoclast

Back 31

Destroys bones!