Chapter 10 Flashcards by Vivian Caloobanan

Type of muscle tissues

Skeletal muscle tissue
Cardiac muscle tissue
Smooth muscle tissue

How well did you know this?

Not at all

Perfectly

Type of muscle that are attached to the skeletal system and allow us to move; they are voluntary muscles,
controlled by nerves of the central nervous system

Skeletal Muscles

How well did you know this?

Not at all

Perfectly

Six Functions of Skeletal Muscle Tissue

Produce skeletal movement
Maintain posture and body position
Support soft tissues
Guard entrances and exits
Maintain body temperature
Store nutrient reserves

How well did you know this?

Not at all

Perfectly

three layers of connective tissues of muscles

Epimysium (Exterior collagen tissue)
Perimysium (Surrounds muscle fiber bundle)
Endomysium (Surrounds muscle cells

How well did you know this?

Not at all

Perfectly

cells that are very long and develop through fusion of mesodermal cells
(myoblasts)

Skeletal Muscle Cells

How well did you know this?

Not at all

Perfectly

The cell membrane of a muscle fiber (cell)

sarcolemma

How well did you know this?

Not at all

Perfectly

Structure that Transmit action potential through cell and allow entire muscle fiber to contract simultaneously

Transverse tubules (T tubules)

How well did you know this?

Not at all

Perfectly

Lengthwise subdivisions within muscle fiber

Myofibrils

How well did you know this?

Not at all

Perfectly

Types of myofilaments

Thin and thick filaments

How well did you know this?

Not at all

Perfectly

Filament made of the protein actin

Thin filaments

How well did you know this?

Not at all

Perfectly

Filament made of the protein myosin

Thick filaments

How well did you know this?

Not at all

Perfectly

A membranous structure surrounding each myofibril that helps transmit action potential to myofibril

Sarcoplasmic Reticulum (SR)

How well did you know this?

Not at all

Perfectly

formed by one T tubule and two terminal

cisternae and is found in the SR

Triad

How well did you know this?

Not at all

Perfectly

Chambers found in SR that concentrate Ca2+ (via ion pumps) and release Ca2+ into sarcomeres to begin muscle
contraction

Cisternae

How well did you know this?

Not at all

Perfectly

The basic contractile units of muscle

Sarcomeres

How well did you know this?

Not at all

Perfectly

The center of the A band and is at midline of sarcomere

M line

How well did you know this?

Not at all

Perfectly

The area around the M line that has thick filaments but no thin filaments

H Band

How well did you know this?

Not at all

Perfectly

The densest, darkest area on a light micrograph where thick and thin filaments overlap

Zone of overlap

How well did you know this?

Not at all

Perfectly

The centers of the I bands found at two ends of sarcomere

Z lines

How well did you know this?

Not at all

Perfectly

strands of protein that reach from tips of thick filaments to the Z line and functions to stabilize the filaments

Titin

How well did you know this?

Not at all

Perfectly

two twisted rows of globular G-actin

F-actin (filamentous actin)

How well did you know this?

Not at all

Perfectly

The active sites on G-actin strands bind to?

myosin

How well did you know this?

Not at all

Perfectly

Holds F-actin strands together

Nebulin

How well did you know this?

Not at all

Perfectly

double strand that prevents actin–myosin interaction

Tropomyosin

How well did you know this?

Not at all

Perfectly

globular protein that binds tropomyosin to G-actin and is controlled by Ca2+

Troponin

Filaments that Contain about 300 twisted myosin subunits and titin strands that recoil after stretching

Thick Filaments

What does the myosin heads do during contraction?

* Interact with actin filaments, forming crossbridges | * Pivot, producing motion

Theory stating that thin filaments of sarcomere slide toward M line, alongside thick filaments; The width of A zone stays the same and Z lines move closer together

Sliding filament theory

Special intercellular connection between the | nervous system and skeletal muscle fiber that controls calcium ion release into the sarcoplasm

neuromuscular junction (NMJ)

What happens during excitation-contraction coupling?

* Action potential reaches a triad * Releasing Ca2+ * Triggering contraction * Requires myosin heads to be in “cocked” position * Loaded by ATP energy

6 steps of the Contraction Cycle

1. Contraction Cycle Begins 2. Active-Site Exposure 3. Cross-Bridge Formation 4. Myosin Head Pivoting 5. Cross-Bridge Detachment 6. Myosin Reactivation

What happens during muscle relaxation?

* Ca2+ concentrations fall * Ca2+ detaches from troponin * Active sites are re-covered by tropomyosin

A fixed muscular contraction after death caused when: • Ion pumps cease to function; ran out of ATP • Calcium builds up in the sarcoplasm

Rigor Mortis

A single contraction or twitch lasts about?

7–100 msec

Period during twitches where the action potential moves through sarcolemma ,causing Ca2+ release

Latent period

Phase during twitches where calcium ions bind and tension builds to peak

Contraction phase

Phase during twitches where Ca2+ levels fall, active sites are covered and tension falls to resting levels

Relaxation phase

A stair-step increase in twitch tension in which repeated stimulations occur immediately after relaxation phase; it causes a series of contractions with increasing tension

Treppe

Increasing tension or summation of twitches in which repeated stimulations occur before the end of relaxation phase; it causes increasing tension or summation of twitches

Wave summation

Condition where twitches reach maximum tensios and if rapid stimulation continues and muscle is not allowed to relax, twitches reach maximum level of tension

Incomplete tetanus

Condition that occurs when stimulation frequency is high enough, causing muscle never begins to relax, and is in continuous contraction

Complete tetanus

Contain hundreds of muscle fibers that contract at the same time and are controlled by a single motor neuron

Motor units in a skeletal muscle

2 Patterns of tension production

* Isotonic contraction | * Isometric contraction

Type of contraction where skeletal muscle changes length resulting in motion;

Isotonic Contraction

type of contraction where muscle shortens if muscle tension > load (resistance)

concentric contraction

type of contraction where muscle lengthens if muscle tension < load (resistance)

eccentric contraction

type of contraction where skeletal muscle develops tension, but is prevented from changing length

Isometric Contraction

Is the primary energy source of resting muscles: • Breaks down fatty acids • Produces 34 ATP molecules per glucose molecule

Aerobic Metabolism

Is the primary energy source for peak muscular activity; it produces two ATP molecules per molecule of glucose and breaks down glucose from glycogen stored in skeletal muscles

Glycolysis

Results of muscle Fatigue

``` • Depletion of metabolic reserves • Damage to sarcolemma and sarcoplasmic reticulum • Low pH (lactic acid) • Muscle exhaustion and pain ```

Term used when muscles can no longer perform a required activity

fatigued

The time required after exertion for muscles to | return to normal

Recovery Period

The removal and recycling of lactic acid by the liver where the liver converts lactate to pyruvate and glucose is released to recharge muscle glycogen reserves

Cori Cycle

Occurs after exercise or other exertion which results to the body needing more oxygen than usual to normalize metabolic activities, which then causes heavy breathing

Oxygen Debt/excess postexercise oxygen | consumption (EPOC)

Three Major Types of Skeletal Muscle Fibers

1. Fast fibers 2. Slow fibers 3. Intermediate fibers

Fibers that contract very quickly and have large diameter, large glycogen reserves, and few mitochondria; they have strong contractions, but fatigue quickly

Fast Fibers

Fibers that slow to contract, slow to fatigue have small diameter, more mitochondria and have high oxygen supply due to myoglobin (red pigment, binds oxygen)

Slow Fibers

Fibers that are mid-sized, have low myoglobin | and more capillaries than fast fibers, and are slower to fatigue

Intermediate Fibers

Muscle growth from heavy training

Muscle Hypertrophy

Term used for lack of muscle activity leading to reduces muscle size, tone, and power

Muscle Atrophy

``` cells that • Are small • Have a single nucleus • Have short, wide T tubules • Have no triads • Have SR with no terminal cisternae • Are aerobic (high in myoglobin, mitochondria) • Have intercalated discs ```

cardiac muscle cells | cardiocytes

Are specialized contact points between | cardiocytes

Intercalated Discs

Functions of intercalated discs

* Maintain structure * Enhance molecular and electrical connections * Conduct action potentials

Contraction without neural stimulation that are controlled by pacemaker cells

Automaticity

Characteristics of Smooth Muscle Cells

• Long, slender, and spindle shaped • Have a single, central nucleus • Have no T tubules, myofibrils, or sarcomeres • Have no tendons or aponeuroses • Have scattered myosin fibers • Myosin fibers have more heads per thick filament • Have thin filaments attached to dense bodies • Dense bodies transmit contractions from cell to cell

Where Ca2+ binds with in the smooth muscle tissue, which results to activation of myosin light–chain kinase

calmodulin