Anatomy and Physiology Chapter 7 pt. 2

What indicates degree of control

the size of motor unit

for Precise movements such as muscles of the eye the motor unit contains ______fibers per neuron; however gross movements such as muscles in the leg, Motor units contain up to ________muscle fibers per neuron

few(4-6);
2000

What is recruitment?

The activation of more and more motor units resulting in an increase in muscle tension to create movement

Which motor units are recruited first?

smaller motor units

What is the result of recruitment

smooth, steady increase in muscle tension

when is peak tension produced

when all motor units are recruited and contracting in complete tetanus

some motor units in skeletal muscle are always on but their contractions are NOT enough to produce tension for movement BUT they do tense and firm the muscle. What is this referring to?

muscle tone

What is muscle tone?

resting tension in a skeletal muscle

what is the purpose of muscle tone

maintain posture, stabilize joints, keep muscles firm and healthy

When muscle is not regularly stimulated by motor neuron what occurs

atrophy

what happens to muscle fibers as a result of atrophy

they become smaller and weaker

atrophy can be obsered after ______ when cast comes off

fracture

when is atrophy reversible

if caused by temporary reduction in use

are Dying muscle fibers ever replaced

no

In Isotonic contraction, _____________ changes but ________remains constant until relaxation

length(shortenin); tension

examples of isotonic contraction

lifting a book, walking

In isometric contraction, __________stays the same, but _____________is produced(does not exceed load)

muscle length;
tension

tension produced by isometric contraction does not __________the load

exceed

exmples of isometric contraction

pushing against a wall

In order for muscle to return back to a pre-contracted, elongated state no ___________mechanism is needed

active

skeletal muscle RELAXATION is a ______________process involving elastic forces, Movements of opposing muscles, Gravity

passive

_____________________muscle fiber generates more ATP than needed

RESTING

When Excess ATP transfers energy to creatine, what forms?

creatine phosphate (CP)

creatine phosphate (CP) stores energy in ___________

muscles

At rest what does muscle have more of? CP or ATP

CP

Cp is created when muscles are at ___________--

rest

During contraction, each cross-bridge breaks down ATP into _________and a __________

ADP; PHOSPHATE GROUP

what is used to recharge ADP back to ATP in a reverse rxn

energy stored in CP

What enzyme is needed for the reverse reaction of creatine phosphate

creatine phosphokinase(CPK or CK)

creatine phosphokinase(CPK or CK) catylzes the conversion of

ADP and creatine phosphate to ATP and creatine

What are kinases?

Kinases are enzymes that transfer the phosphate group of ATP to a specialized molecule.

High levels of CPK in the blood can indicate ________________

serious muscle damage

when energy reserves become exhausted after 15 sec atp must be generated by different means such as ________________ and _________________

aerobic metabolism and anaerobic glycolysis

aerobic metabolism provides _________% of resting muscle cell's ATP needs

95

All stages of cellular Respiration except glycolysis occur in the _________

MITOCHONDRIA

Aerobic metabolism Involves breaking down of ___________, _______________, and ______________- into smaller components

carbohydrates, lipids, and proteins

aerobic metabolism end products

ATP, water, and carbon dioxide

Where does glycolysis occur?

cytoplasm

What are the products of glycolysis?

2 pyruvate, 2 ATP, 2 NADH

NADH is an _______________which carries electrons from glycolysis to ETC(electron transport chain)

electron shuttle

ETC occurs in the

inner mitochondrial membrane

energy from electrons is used by ETC to create ________________

H+ gradient

The H+ gradient refers to __________________distribution of H+ across across inner mitochondrial membrane

equal

The H+ gradient is used by enyme ________________--to make ATP from ADP and phosphate

ATP synthase

each NADH leads to the production of how many ATP by chemiosmosis

2.5

What is the second stage of aerobic respiration

pyruvate oxidation

Where does pyruvate oxidation occur?

mitochondrial matrix(outside cytoplasm)

pyruvate uses 2 molecules of pyruvate to produce

2 acetyle Co-A, 2 NADH, and 2 CO2

Like pyruvate oxidation, the krebs cycle occurs in_____________

mitochondrial matrix

Krebs cycle uses 2 molecules of acetyl Co-A to produce(TWICE)

6 NADH, 2 FADH2, 4CO2, 2ATP

Aside from NADH, which of the following is an electron shuttle

FADH2

FADH2 delivers electrons to___________which creates H+ gradient

ETC

each FADH2 leads to the production of _________( how many )ATP by ___________

1.5; chemiosmosis

oxidative phosphorylation includes

ETC and chemiosmosis

Where does oxidative phosphorylation occur?

inner mitochondrial membrane

inner mitochondrial membrane seperates mitochondrial matrix from___________

intermembrane space

How many molecules of ATP does oxidative phosphorylation produce

28

overall ____ atp are produced
____atp from glycolysis, _____atp from krebs cycle, __________from oxidative phosphoraltion

30, 2, 2, 28

The 30 ATP are used to transport ___(how many) glycolytic NADH (produced during glycolysis) from the cytoplasm to mitochondrion

2

In the presence of oxygen (aerobic) the cell produces _____molecules of atp by using _________ molecule of glucose

30; 1

it is also true to say that ___molecules of pyruvate lead to the production of 30 molecucles of ATP

2

at rest skeletal muscle cells rely on ______________to make atp

aerobic metabolism

Triglycerides are broken down into

fatty acids and glycerol

what enzymes catalyze the break down of fats to fatty acids and glycerol

lipases

skeletal muscles cell use fatty acids to produce _____________, _______________ , and____________in the ____________during a process called fatty acid(beta) oxidaton

acetyl CoA, NADH, FADH2;
mitochondrial matrix

acetyl CoA is needed for _________ to happen;
NADH and FADH2 are needed for ________ to work

krebs cycle;
ETC

the generated atp is used by skeletal muscle cells to convert excess glucose into ______________

glycogen

conversion of glucose to glycogen in the presence of ATP

anabolism

at moderate activity, the demand for ___increases.
the rate of _____________use also increases

atp;
oxygen

at moderate activity glycogen is broken down into ______________ in a catabolic process

glucose

during moderate activity the atp produced is used to power ___________--

contration

only when ________is present can skeletal muscle make 30 atp/ glucose

oxygen

when does peak activity occur

during severe or extended periods of exercise

at peak activity, skeletal muscles run out of __________and rely on _________to produce only ___molecules of ATP

oxygen;
glycolysis; 2

During glycolysis, glucose is broken down into

2 molecules of pyruvate;

Glycolysis produces how many ATP?

2 ATP

2 molecules of pyruvate are used by skeletal muscle cells to produce TWO molecules of

lactate(aka lactic acid)

lactic acid fermentation

The conversion of pyruvate to lactate with no oxygen.

Where does lactic acid fermentation occur?

cytoplasm of skeletal muscle cells

in the presence of oxygen hydrogen ions are___________ by mitochondria
In the absence of oxygen hydrogen ions _____________with lactic acid

absorbed;
accumulate

what happens to the pH of our muscles when hydrogen ions accumulate with lactic acid

decreases!!

as a result of pH decreasing, what happens to muscles?

muscle FATIGUE;
metabolic(lactic) acidosis

Where is the majority of ATP produced during PEAK activity?

glycolysis(w/ acetate and H+ as biproducts)

During muscle fatigue, the muscle will no longer perform at required level EVEN if _____________

stimulated

why does muscle fatigue affect sprinters more quickly

they rapidly build uo lactic acid

how does muscle fatigue affect the muscles of marathon runners?

after using stores of glycoge and lipids(depletion of energy reserves)

What is the recovery period?

time required after exertion for muscles to return to normal

How is the recovery period carried out

restoring oxygen levels, removing lactic acid, replacing intracellular energy reserves, Losing heat produced during contraction

how is the removal of lactic acid after exercise(recovery period) carried out?

releasd into blood, sent to liver, converted to glucose in liver (energy source)

liver uses extra glucose to make _________

glycogen

AT rest our muscles have more ____________than ATP

CP(creatine phosphate)

At rest, the rate of heat loss________

increases(blood flow increases and sweat gland secretions increase)

How is muscle performance measured?

force and endurance

what is force

max amt of tension produced by muscle or muscle group

what is endurance

the amount of time an activity can be sustained

What two factors determine performance

1. Types of fibers in muscle (fast-twitch and slow-twitch)
2. Physical conditioning or training

Wat is the most common type of fibers in our muscles

fast twitch fibers

why are they called fast(fast twitch) fibers

they reach peak tension very quickly

fast(fast twitch) fibers have a large _________ and ______________

diameter, glycogen reserves

Why do fast(fast twitch) fibers rely on glycolysis

bc they have few mitochondria