Chapt. 9 - Muscles & Muscle Tissue

Front 1

3 Types of Myo Tissue

Back 1

a) Skeletal – striated & voluntary

b) Cardiac – striated & involuntary

c) Smooth – nonstriated & involuntary (visceral)

Front 2

Characteristics of Myo Tissue

Back 2

-Excitability
-Contractility – the ability to shorten forcibly

-Extensibility

-Elasticity

Front 3

The end of the myo that connects to the non-moving bone

Back 3

Origin

Front 4

The movable end of the muscle

*[Only one bone moves when a muscle contracts]

Back 4

Insertion

Front 5

Gross Anatomy of Skeletal Myo

Back 5

*Long and Cylindrical, Multinucleated

Front 6

Connective Tissue Sheathes

(Continuous with tendon)

Back 6

Epimysium – Surrounds entire Myo

Perimysium – Surrounds fascicles (groups of myofibers)

Endomysium – Surrounds each individual fiber (cell)

Front 7

Attachments to Bone

Back 7

-Direct Attachment – Epimysium attaches directly into bone

-Indirect Attachment – (Tendon) Rope-like

Front 8

Aponeurosis

Back 8

Sheet-like attachment

[muscle to muscle, made of same material as tendon but notrope, sheet]

Front 9

Microscopic Anatomy

Back 9

Microscopic Anatomy

Front 10

Sarcolemma

Back 10

The plasma membrane of the myo cell

Front 11

Sarcoplasm

Back 11

The cytoplasm;

-Contains all the normal organelles of a cell….. and more:

Myoglobin – A red pigment that stores O2 in myo cells

Myofibrils

Sarcoplasmic Reticulum

T-Tubules

Front 12

Myofibrils

Back 12

Make up 80% of the cellular volume; they contain contractile elements of the myocell called sarcomeres

Front 13

Sarcomeres

Back 13

Are composed of myo filaments, producing the striations of a myocell

*Sarcomere is “THE” functional unit of a myocell! [From one Z disc to another; bring Z disc closer/further]

Front 14

Within the myofibrils are proteins:

Back 14

(Myofilaments):

Actin - Thin&

Myosin – Thick

Front 15

The filaments are anchored by a:

Back 15

Z disc

Front 16

During myo contraction, (the sliding filament model):

Back 16

The Actin & Myosin slide past each other and partially overlap

Front 17

Myosin

Back 17

Many molecules, each with a protruding head that forms cross-bridges by attaching to Actin filaments (during myo contraction)

Front 18

Actin

Back 18

Thin filament shaped like a helix of beads…Each bead has an active site;

The myosin heads attach to these sites during contraction

Front 19

Tropomyosin

Back 19

Block myosin binding sites; serving as acontraction inhibitor

Front 20

Troponin

Back 20

Binds to calcium (Ca++) Ions; Regulatory sites that Ca++ binds to [moves the tropomyosin]

Front 21

Sarcoplasmic Reticulum

Back 21

– *Functions to store calcium Ca++

– Ultimately, its major function is to regulate intracellular Ca++ concentration

Front 22

Terminal Cisternae

Back 22

Part of sarcoplasmic reticulum; appears in pairs…it releases the Ca++ when the myofiber is stimulated

Front 23

T-Tubules

Back 23

An extension of the sarcolemma that extends deep into the myo fiber…they are located between terminal cisternae

Front 24

*T-Tubules enhance cellular communication during myo contraction by:

Back 24

-They conduct electrical impulses “deep” into thefiber (cell)

-They communicate these impulses to the Terminal Cisternaeadjacent to them

Front 25

The Motor End Plate

Back 25

The part of the sarcolemma that helps form the neuromuscular junction. -Has millions of receptors for ACh - acetylcholine

Front 26

When the _________ reaches the end of the ____________, the axon terminal releases ACh into the _______.

Back 26

impulse (AP), motor axon, cleft

Front 27

Ca++triggers the release of the _______________

Back 27

neurotransmitter Ach

Front 28

ACh crosses the cleft and attaches to receptorsites ON the_____________ ….triggering:

Back 28

sarcolemma......electrical events giving us muscles contraction

Front 29

Acetylcholinesterase

Back 29

*After binding, the enzyme in the cleft that breaks down ACh that remains unused. (If no further stimulation occurs) Preventing further muscle contraction.

Front 30

Energy for contraction (ATP)

Back 30

(Adenosine triphosphate)

1. Direct phosphorylation of ADP by creatine phosphate – stores energy that will be transferred to ADP to resynthesize ATP

2. Anaerobic pathway (glycolysis) – As stored ATP & CP are exhausted, more ATP can be obtained from blood glucose, or stored glycogen in the myo.

Front 31

1. Direct phosphorylation of ADP by creatine phosphate

Back 31

Front 32

Glycolysis

Back 32

(no O2 needed) An anaerobic pathway where a glucosemolecule can be broken down into 2 pyruvic acid molecules to attain 2ATP’s;

In the absence of O2, pyruvic acid not used for ATP isconverted into lactic acid.This energy can last 30-40 seconds

Front 33

2. Anaerobic pathway (glycolysis)

Back 33

Front 34

Energy for contraction

Back 34

3. Aerobic Respiration-Must have O2 present-Takes place in mitochondria via the citric acid cycle aka Krebs Cycle-*One molecule of glucose can produce 32 ATP’s-This energy will last as long as raw materials last (Carbs)

Front 35

3. Aerobic Respiration

Back 35

Front 36

Myo Fiber Types

Back 36

Slow oxidative fibers (Endurance) [red, blood cells]

Fast glycolytic fibers (short, rapid, intense movements) [white, glycogen]

-Most skeletal myos contain a mixture of fiber types