Bio 10

Front 1

Excitability

Back 1

Plasma membranes can change their electrical states (polarized to depolarized) and send an electrical wave called an action potential along the length of the membrane.

Front 2

Aponeuroses

Back 2

Flat tendon sheet

Front 3

Elasticity is a quality of muscle tissue that...

Back 3

Can return to its original length when relaxed due to elastic fibers

Front 4

Extensibility

Back 4

Stretch or extend

Front 5

Contractility

Back 5

Allows muscle tissue to pull on its attachment points and shorten with force

Front 6

Differences among 3 muscle types are organization of contractile proteins...?

Back 6

Actin and myosin

•These proteins are arranged in lines (striations) in cytoplasm of skeletal and cardiac muscle.

•In smooth muscle, the cytoplasm of muscle fiber (which has single nucleus) has a smooth appearance

Front 7

Sarcolemma

Back 7

Plasma membrane of muscle fibers

Front 8

Sarcoplasm

Back 8

The cytoplasm in a muscle fiber

Front 9

How many myofibrils are in a muscle fiber ?

Back 9

Hundreds to thousands

Front 10

Sliding filament model of contraction

Back 10

•The process of which a skeletal muscle fiber contracts as the thin filaments are pulled and then slid past the thick filaments within a sarcomere.

•The sliding can only occur when myosin-binding sites on the actin filaments are exposed by a series of steps that begin with Ca++ entry into sarcoplasm

Front 11

Myogram

Back 11

An instrument that measures the amount of tension produced by a twitch over time.

Front 12

3 phases each twitch undergoes

Back 12

•Latent period- the action potential is being propagated along the sarcolemma and Ca++ is released from the SR (excitation & contraction are being coupled)

•Contraction phase- Ca++ in the sarcoplasm have bound to troponin, tropomyosin shifted, cross bridges formed, and sarcomeres actively shorten to peak tension.

•Relaxation phase- When tension decreases as contraction stops. Ca++ is pumped out of sarcoplasm into SR, cross bridgs cycling stops, and muscle fibers return to relaxed state.

Front 13

Graded muscle response

Back 13

Contraction of a muscle with varying degrees of force dependent on the circumstance.

•They do this through wave summation

-Wave summation is an increase in muscle contraction strength based on how rapidly a muscle is stimulated. This occurs because muscles that are rapidly stimulated are not able to relax between repeated stimulations.

Front 14

Tetanus

Back 14

During tetanus, the concentration of Ca++ in the sarcoplasm allows virtually all of the sarcomeres to form cross bridges and shorten, so that a contraction can continue uninterrupted (until muscle fatigue)

Front 15

Treppe

Back 15

(Staircase effect)

A condition where muscle contractions become more efficient.

- Treppe results from a higher concentration of Ca++ in sarcoplasm resulting from steady stream of signals from motor neuron.

Front 16

Hypotonia

Back 16

The absence of low level contractions that lead to muscle tone (atrophy) and can result from damage to parts of the CNS (cerebellum), or from loss of innervations to a skeleton muscle (poliomyelitis)

Front 17

Hypotonic muscles have what kind of appearance

Back 17

Flaccid and they display weak reflexes

Front 18

Hypertonia

Back 18

Excessive muscle tone, accompanied by hyperreflexia (excessive reflex response).

•often result of damage to upper motor neurons in the CNS

Front 19

Hypertonia is characterized by...

Back 19

Muscle rigidity (Parkinson's) or spasticity (some strokes)

Front 20

3 main types of skeletal muscle fibers

Back 20

•Slow Oxidative (SO): fibers contract relatively slowly and use aerobic respiration (oxygen and glucose) to produce ATP.

•Fast Oxidative (FO): fibers have fast contractions and primarily use aerobic respiration, but because they may switch to anaerobic respiration, can fatigue more quickly than SO fibers.

•Fast Glycolytic (FG): fibers have fast contractions and primarily use anaerobic glycoIysis. The FG fibers fatigue more quickly than others.

Front 21

If a fiber primarily produces ATP through aerobic pathways it is...

Back 21

Oxidative

Front 22

The Oxidative fibers contain many more _____ than Glycolytic fibers because aerobic metabolism (which uses oxygen in the metabolic pathway) occurs in this.

Back 22

Mitochondria

Front 23

SO fibers contain a large number of ____, _____, and _____

Back 23

Mitochondria, blood Capillaries, and myoglobin

Front 24

Maintaining posture, producing Isometric contractions, stabilizing bones and joints, and making small movements that do not require large amounts of energy are due to what fibers?

Back 24

SO fibers

Front 25

FO fibers are sometimes called what?

Back 25

Intermediate fibers- they possessed characteristics that are Intermediate between fast fibers and slow fibers

Front 26

FO fibers are primarily used for what?

Back 26

Movements (walking) that require more energy than posture control but less energy than an explosive movement (sprinting)

Front 27

FO fibers produce ____ tension than SO fibers but are ____ fatigue resistant than FG fibers

Back 27

More tension and more fatigue

Front 28

FG fibers are useful for?

Back 28

Rapid, forceful contractions to make powerful movements.

•These fatigue quickly however and can only be used for short periods

Front 29

What happens to muscles cells when they grow in strength?

Back 29

New cells are not formed when muscles grow, instead structural proteins are added to muscle fibers in a process called hypertrophy (cell diameter increases)

Front 30

Age related muscle atrophy is called what?

Back 30

Sarcopenia

Front 31

What type of training modifies slow fibers to make them more efficient by producing more mitochondria to enable more aerobic metabolism and more ATP production.

Back 31

Endurance training

Front 32

Endurance exercise can increase ____ in a cell

Back 32

Myoglobin

Front 33

Myoglobin is found where?

Back 33

In the sarcoplasm and acts as an oxygen storage supply for mitochondria

Front 34

Angiogenesis

Back 34

Endurance training can trigger the formation of more extensive capillary networks around the fiber to supply O2 and remove waste

Front 35

Resistance exercises require what type of fibers ____?

Back 35

Large amounts of FG fibers

- Causes increased amount of myofibrils

Front 36

Resistance training increases development of what tissues?

Back 36

Connective tissues and tendons become stronger

Front 37

Resistance training involves a lifter to weights in what pattern?

Back 37

Gradual increase of heavier weights

Front 38

Anabolic steroids

Back 38

A form of male testosterone

Front 39

Endurance athletes will what substance to increase aerobic respiration?

Back 39

Erythropoietin (EPO)- a hormone normally produced in the kidneys, which triggers production of red blood cells.

Front 40

Human growth hormone (hGH)

Back 40

It's main role is to promote healing of muscle and other tissues after strenuous exercise.

Front 41

Dangerous side affects of Anabolic steroids

Back 41

Infertility, aggressive behavior, cardiovascular disease, and brain cancer

Front 42

As muscles age, muscle fibers die and are replaced by what ?

Back 42

Connective tissue and adipose tissue

Front 43

Cardiac muscle

Back 43

•Shorter than skeletal and have 1 nucleus

•Possess many mitochondria and myoglobin, ATP produced by aerobic respiration

Front 44

Intercalated disc

Back 44

Cardiac muscle cells are connected to one another by these. They allow the cardiac muscle to contract in a wave pattern so the heart can work as a pump

Front 45

Intercalated discs are part of the _____

Back 45

Sarcolemma

Front 46

What are the two important structures of intercalated discs

Back 46

•Gap Junctions- forms a channel between adjacent cardiac muscle fibers that allow the depolarizing current produced by cations to flow from one cardiac muscle cell to the next.

•Desmosomes- a cell structure that anchors the ends of cardiac muscle fibers together so the cells do not pull apart during the stress of individual fibers contracting.

Front 47

Syncytium

Back 47

The network of electrically connected cardiac muscle cells that creates a functional unit of contraction

Front 48

Contractions of the heart (heartbeat) are controlled by what cells?

Back 48

Pacemaker cells- they directly control heart rate.

Front 49

Pacemaker cells respond to signals from what to speed up or slow down

Back 49

Autonomic nervous system (ANS)

•They can also respond to hormones that model a heart rate to control blood pressure

Front 50

Autorhythmicity

Back 50

The group of pacemaker cells are self excitable and are able to depolarize to threshold and fire action potentials on their own (they do this at set intervals)

Front 51

More features of cardiac muscle:

Back 51

•Long action potentials, having a sustained depolarization "plateau".

•The plateau is produced by Ca++ entry through voltage gated calcium channels in sarcolemma of muscle fibers.

•Large % of Ca++ that initiates contraction comes from outside the cell rather than from SR.

Front 52

Smooth muscle is found where ?

Back 52

Hollow organs and in the eyes and skin

Front 53

How much shorter are smooth muscle fibers to skeletal muscles?

Back 53

Thousands of times shorter

Front 54

Smooth muscle fibers contain...

Back 54

•Actin

•Myosin contractile proteins

•Thick filaments

•Thin filaments

Front 55

a Dense Body

Back 55

Similar to the Z-discs of skeletal muscle and cardiac muscle fibers and is fasted by the sarcolemma

Front 56

Calmodulin

Back 56

Allows smooth muscle to activate an enzyme called myosin (light chain) kinase which in turn activates the myosin heads by phosphorylating them. Then the heads can attach and pull on thin filament

Front 57

Photo of smooth muscle contraction

Back 57

The middle is bulged in a corkscrew motion

Front 58

Smooth muscle is able to function for long periods without rest through what?

Back 58

Latch bridges- keep the thick and thin filaments together for a prolonged period and without need for ATP

Front 59

Trigger for smooth muscle contraction

Back 59

Hormones, neural stimulation by ANS, and local factors

Front 60

Varicosity

Back 60

Releases neurotransmitters into the synaptic cleft

-Visceral muscle in the walls of the hollow organs (except heart) contain pacesetter cells

Front 61

Pacesetter cell

Back 61

Can spontaneously trigger action potentials and contraction in the muscle

Front 62

Single unit muscle (smooth muscle)

Back 62

Visceral Muscle

•Muscle fibers join by gap Junction so that the muscle contracts a single unit.

•Found in the walls of all visceral organs except the heart

Front 63

Stress-relaxation response of Visceral muscle

Back 63

As the muscle of a hollow organ is stretched when it fills, the mechanical stress of the stretching will trigger contraction, this is immediately followed by relaxation so that the organ does not empties contents prematurely

Front 64

Multiunit smooth muscle

Back 64

•Rarely possess gap junctions.

•Stimuli for these muscles come from autonomic nerves or hormones.

•Found around large blood vessels, in respiratory airways, and in eyes.

Front 65

Hyperplasia

Back 65

Smooth muscle can divide to produce more cells.

-Uterus at puberty (producing more uterine smooth muscle fibers)

Front 66

Somites

Back 66

Paraxial mesoderm cells adjacent to the neural tube form these blocks of cells

•Skeletal muscles (not head or limbs) develope from these

Front 67

Somites give rise to____

Back 67

Myoblasts- a muscle forming stem cell that migrates to different regions of the body and then fuses to form a myotube

Front 68

Satellite cell

Back 68

(Help repair skeletal muscle cells)

Similar to a myoblast because it is a type of stem cell; However, satellite cells are incorporated into muscle cells and facilitate the protein synthesis required for repair and growth

Front 69

Fibrosis

Back 69

A process in which muscle fibers are replaced by scar tissue if they cannot be repaired by satellite cells

Front 70

Pericyte

Back 70

A type of stem cell that smooth muscle can regenerate from (found in some small blood vessels)