Flashcards ANP Chap 10, 11, 12

Functions of muscle tissue

Movement, stability, control openings/passages, heat production

3 types of muscle

Skeletal, cardiac, smooth

Cardiac muscle

-Striated

-Uninucleate

-Found in the heart

-Input= ANS neurons

-Involuntary

Skeletal muscle

-Striated

-Multinucleate

-Attached to bones

-Input= somatic motor neurons

-Voluntary

Smooth muscle

-Not striated

-Uninucleate

-Blood vessels, viscera

-Input= ANS neurons, hormones

-Involuntary

Endomysium

Surrounds muscle fiber

Perimysium

Surrounds fascicle (little bundle)

Epimysium

Surrounds entire muscle

Facia

Separates muscle/muscle groups

Tendon

Dense CT, connects muscle to bone

Aponeurosis

Broad tendon sheet

Retinaculum

Band of CT that covers tendons (little bracelet)

Origin

Attachment at stationary end

Belly

Thick middle part

Insertion

Attachment at mobile end

Action

Movement produced by muscle

Prime movers

Muscle that produces the most force during an action

Antagonists

Muscle that opposes action of prime mover

Synergists

Muscle that aids prime mover

Fixators

Muscle that restricts bone from moving

Rectus

"Straight"

Oblique

"At an angle"

Transverse

"Horizontal"

Deltoid

Triangle

Orb

Circle

Muscles in the rotator cuff (SITS)

Supraspinatus, infraspinatus, teres minor, subscapularis

Muscles in the hamstrings

Biceps femoris, semitendinosus, semimembranosus

Muscles in the quadriceps

Rectus femoris, vastus lateralis, vastus medialis, vastus intermedius

Specialized characteristics of muscle tissue

Excitability- cell membrane voltage can change

Conductivity- electrical changes spread across cell

Contractility- shortens when stimulated

Extensibility- stretchable

Elasticity- recoils when tension is released

Structure of skeletal muscle from gross to microscopic levels

Muscle, epimysium, fascicles, perimysium, muscle fibers, endomysium, sarcolemma, myofibril, myofilaments

Sarcolemma

Membrane

Sarcoplasm

Cytoplasm

Sarcoplasmic reticulum

Smooth ER that stores calcium

T-Tubules

Infoldings on membrane

--

--

Myosin

Thick myofilament

Troponin, tropomyosin, and actin

Thin myofilament

A band

Thick and dark

I band

Thin and light

H band

Thick myosin only, no thin overlap

Z disc

Anchor thin filament

M line

Hold myosin in place

Motor unit

Activation of a neuron causes all fibers in the motor unit to contract

Small motor unit

3-6 fibers, fine motor control

Large motor unit

100-1000's of fibers, strength

Neuromuscular junction

Connection between motor neuron and muscle fiber (synapse)

Synaptic vessels

Store neurotransmitters

Neurotransmitter (ACh)

Enables muscle action

ACh receptors

Bind to muscle membrane

Acetycholinesterase (AChE)

Breaks down ACh

6 steps of skeletal muscle fiber contraction

1- Activation of motor neuron

2- Signal transmitted to the muscle fiber at the neuromuscular junction

3- Excitation of muscle fiber

4- Excitation-contraction coupling

5- Contraction

6- Relaxation

Step 1 (excitation of muscle fiber)

Arrival of nerve spinal

Step 2 (excitation of muscle fiber)

ACh release via exocytosis

Step 3 (excitation of muscle fiber)

Binding ACh to receptor

Step 4 (excitation of muscle fiber)

Sodium flows in, potassium flows out, causes voltage change

Step 5 (excitation of muscle fiber)

Opening of voltage-regulated ion gates; creation of action potentials

Step 6 (excitation-contraction coupling)

Action potentials propagated down T tubules via voltage gated channels

Step 7 (excitation-contraction coupling)

Voltage change opens calcium channels in SR

Step 8 (excitation-contraction coupling)

Calcium binds to troponin

Step 9 (excitation-contraction coupling)

Tropomyosin moves out of the way

Step 10 (contraction)

Hydrolysis of ATP to ADP, myosin head is activated

Step 11 (contraction)

Formation of the myosin-actin cross bridge

Step 12 (contraction)

Power stroke (movement) of thin filament over thick filament

Step 13 (contraction)

Binding of new ATP; breaking of cross-bridge

Step 14 (relaxation)

No nerve signal

Step 15 (relaxation)

AChE breaks down ACh

Step 16 (relaxation)

Reabsorption of calcium ions by sarcoplasmic reticulum

Step 17 (relaxation)

Loss of calcium ions from troponin

Step 18 (relaxation)

Elastic recoil of opposing muscle brings muscle back to restoring length

Rigor mortis

"Stiffness of death"

Muscle twitch

Tension from a single action potential

Length-tension relationship

The resting length of a muscle and the tension the muscle can produce at this resting length

Overly contracted muscles

Overlapping thin filaments and interfere with cross bridges

Optimum resting length

Optimal filament overlap, maximized the # of cross bridges

Overly stretched muscles

Little/no overlap, no cross bridges can form

Motor unit recruitment

Primary means of varying tension in whole muscle

Temporal summation

Increasing stimulus frequency = more tension

Muscle twitches

Complete relaxation between stimuli

Incomplete tetanus

High tension because the muscle can't fully relax between muscle twitches

Complete tetanus

No relaxation between twitches

Isometric contraction

Muscle develops tension but does not shorten (ex. holding a dumbbell)

Isotonic contraction

Muscle shortens but tension remains constant (ex. curling a dumbbell)

Concentric movement

Shortening (ex. standing up from a squat or curling a dumbbell)

Eccentric movement

Lengthening (ex. lowering into a squat or lowering a dumbbell)

Equation for cellular respiration

C6H12O6 (glucose) + 6O2 (oxygen) ---------> 6CO2 (carbon dioxide) + 6H2O (water) + energy

Role of ATP

-Muscle contraction

-Active transport

-"Energy cash"

Anabolism

Energy storage reactions

Catabolism

Energy releasing reactions

Cofactors

Inorganic molecules needed for enzyme function

Coenzymes

Organic cofactors derived from vitamins

Glycolysis

Glucose --> pyruvic acid + 2 ATP

Anaerobic fermentation

If no oxygen, pyruvic acid --> lactic acid (happens in the cytoplasm)

Aerobic respiration

If there is oxygen, pyruvic acid --> CO2 + H2O + lots of ATP (happens in the mitochondria)

Citric acid cycle (Kreb's cycle)

- 2 Pyruvates enter the mitochondria

- Releases 6CO2, 2 ATP, 8NADH, and 2 FADH2 for each glucose

- Happens in the mitochondria

Electron transport chain

Transfers energy from NADH + H and FADH to make ATP, needs oxygen or it won't work

Importance of oxygen in cellular respiration

Oxygen is the final step in the electron transport chain, allowing for the production of ATP

Advantages/disadvantages of lipids in APT production

Advantages: Enables glycolysis to continue (regenerates NAD+)

Disadvantages: Lactic acid is toxic, no more energy is contracted (no more ATP!)