KRS 354 exam 1

What is the Basement Membrane? (Function, location, etc)

What is the Basement Membrane? (Function, location, etc)

- Mechanical function

- Superficial to the muscle fiber

- Attaches the muscle fiber to the endomysium (structural component)

- Stops signaling of Action potential by releasing Acetylcholinesterase which breaks down ACH by hydrolysis

What is the Plasmalemma? a. (Function, location, etc)

- Gate keeper (true cell membrane), allows what goes in and out of the cell

- Located deep in the muscle fiber

- Fuses with the tendon

- Transmits Action potential down the cell

Where are satellite cells located?

outside of the sarcolemma under muscle basement membrane

What are satellite cells?

They are undifferentiated cells that can turn into nuclei or muscle fibers to help with muscle growth (hypertrophy)

what is syncytia?

When a muscle cell or fiber contains more than one nuclei in order to support the large muscle fiber and helps with muscle development

what is the purpose of the sarcoplasm?

- regulates the concentration of calcium

- determines whether muscle contraction occurs

- It is a gelatin like substance that stores glycogen, myoglobin, other proteins, minerals, fats and organelles

What is the purpose of T tubules?

- conduct impulses from cell surface

- calcium release for SR

- Gets rid of waste products

what are 3 protein molecules that connected to actin called?

troponin, tropomyosin, and nebulin

Troponin

calcium binds

tropomyosin

covers myosin head binding site

nebulin

anchoring protein, keeps actin together

What is a sarcomere?

basic contractile unit comprised of thin actin and thick myosin filaments; contractile repeating unit of a striated muscle fiber of myofibril, between two z-lines

what is a motor unit?

A motor unit is an alpha-motor neuron and all the muscle fibers it directly innervates

I band

The light area around the Z-line consisting thin actin filaments not overlapped by thick myosin filaments

A band

The dark area which spans the length of the thick myosin and I always constant

H zone

The zone in the center of the A-band where myosin are not overlapped by the actin

Z line

It forms the periphery of the sarcomere where the thin actin filaments attach; ends of sarcomere

M line

attachment site for thick filaments, center of A band (middle of sarcomere)

Summation

- the effect of several electrical impulses on a junction

- Ex. When something is heavier than it seems and you do a slight pause to gain more force

Tetanus

- a muscle contraction when a motor nerve emits action potentials, it is continuous, the muscle is not relaxed

- Ex. isometric holds

sarcomere during concentric contraction

muscles shorten and the myosin heads draw actin towards each other making the sarcomere shorten

sarcomere during eccentric contraction

myosin cross-bridges attach and the actin move away from each other lengthening the sarcomere

ion concentrations inside cell

potassium- 150 mM

sodium- 15 mM

ion concentrations outside cell

potassium- 5 mM

sodium- 150 mM

characteristics of type 1 fibers

-

Characteristics of type 2 fibers

- >=300 muscle fibers

- fast twitch fibers

- low oxidative capacity

- high glycolytic capacity

- More developed SR = more Ca2+ released

- Second to develop

larger sized neurons

Lower resistance to fatigue

is the hydrolysis of ATP an exergonic or endergonic reaction?

exergonic reaction because energy is being released

is phosphorylation of ATP an exergonic or endergonic reaction?

endergonic reaction because energy is absorbed

first law of thermodynamics

energy neither can be created nor destroyed, it can be converted from one form to another

second law of thermodynamics

entropy always increases in an isolated system

what is the purpose of enzymes?

speed up the rate of chemical reactions and aid in digestion and metabolism

what is LDH?

an enzyme that catalyzes lactate to pyruvate, has an important role in the body's energy/damages tissues.

what is the composition of air?

- 79% Nitrogen (N2)

- 20.93% Oxygen (O2)

- 0.03% Carbon Dioxide (CO2)

what is the Haldane transformation?

- determine volume of air ventilated, measures resting and maximum oxygen consumption

What are the three components to determine VO2?

- Volume air expired

- O2% in expired air

- CO2% in expired air

what is RER?

respiratory exchange rate

- tells us what substrate is used during activity

- VCO2 expired/VO2 consued

L O2 ---> kcal

1L O2= 5 kcal

Protein calorie value

4 kcal

carbohydrates (CHO) calorie value

4 kcal

fat calorie value

9 kcal

Resting Metabolic Rate (RMR) conversion (mL/kg/min)

- 3.5 ml/kg/min= 1 MET

- Energy required to maintain resting functions

ventilatory threshold (VT)

- the point at which H+ production increases and the body is not able to buffer against acidosis which increases VE and CO12

- measure used to characterize endurance atheletes and predict performance

What causes fatigue?

- substrate depletion

accumulation of byproduct (Pi and H+)

- failure of sarcomere

- CNS/gov theory

layers of muscle

a. Muscle belly-->Fascicle-->Muscle fiber

b. Epimysium--> Perimysium-->Endomysium

type 2b fibers

fastest twitch fibers

what are the rate limiting enzymes for glycolysis?

- phosphofructokinase (PFK)

- Phosphorylase

- hexokinase

time of exercise for phosphagen system

high intensity exercise lasting

time of exercise for glycolysis

exercise lasting 2-3 minutes

time of exercise for aerobic

prolonged exercise lasting 90-180 minutes

DOMS

delayed onset muscle soreness, 24-48 hours after

muscle spindle

a receptor parallel to the muscle that responds to a stretch

automatic nervous system

controls involuntary actions

somatic

voluntary

Parasympathetic

- rest and digest

sympathetic

- fight or flight

premotor cortex

The region controlling learned motor skills.

primary motor cortex

the section of the frontal lobe responsible for voluntary movement

What are the rate limiting enzymes in the Krebs cycle?

Isocitrate dehydrogenase

Depolarization graph

depolarization (absolute refractory period), overshoot, repolarization, hyperpolarization (relative refractory period)

What is the Relative Refactory Phase and the voltage

another action potential can be sent; -50--55

infrafusal muscle fibers

serve as specialized sensory organs that detect the amount and rate of change in length of a muscle

extrafusal muscle fibers

surrounding muscle fibers supplied by alpha motor neurons

Cholinergic deficit (? lbs deficit -> ? kcals)

1 lbs deficit -> 3500 kcal

What is the body's preferred source of energy?

carbohydrates

Pyruvate

end product of glycolysis

What determines the type of muscle fiber?

The fiber is determined by the type of myosin ATPase

Which athlete has more type II muscle fibers?

Athletes who do exercises that do exercises/actions less than 30 sec. (Gymnast, powerlifters)

Which athlete has more type I muscle fibers?

Athletes who do exercises longer than 30 sec and need more endurance (Long distance runners)

What are the rate limiting enzymes in the phosphagen system?

1. Creatine Kinase (CK)

2. Adeylate Kinase (AK)

What are the rate limiting enzymes in the ETC?

Cytochrome C Oxidase

How many ATP are produced from the complete metabolism of glucose?

- Glucose = 32 ATP

- Glycogen = 33 ATP

Which reactions cost an ATP in the 1st phase of glycolysis?

- Glucose = -2 ATP

- Glycogen = -1 ATP

How many NADH and FADH are produced the complete metabolism of glucose? Glycogen?

Glucose and Glycogen produces 10 NADH and 2 FADH

How many ATP are derived from NADH and FADH via the ETC?

NADH produces 2.5 ATP and FADH produces 1.5 ATP

What is the end product of the last step of anaerobic glycolysis? What is its fate?

The end product is pyruvate. If there is too much pyruvate, then lactic acid will occur making the body more fatigue. If the body has more time and has O2, it will enter the krebs cycle

Where does glycolysis occur?

Cytoplasm

Where does the Krebs cycle and the ETC occur?

mitochondria

When is each metabolic system used? ie: phosphagen, glycolysis, aerobic

- Phosphagen system:

When does Cori cycle occur?

when you exceed the amount of pyruvate

What is the function of the dendrites?

Receive the impulses from another

What is the function of the axon?

Sends the impulse away from the cell body

What is the function of the myelin sheath?

Helps AP move faster

What is the function of the axon terminals?

Contains numerous vesicle that contain neurotransmitters and when a stimulus has reached, they will release the neurotransmitters to communicate to the next neuron or muscle fiber

What is the resting membrane potential of a neuron?

- Overall: -70 mV

- Na+ inside: 15 mM

- Na+ outside: 150 mM

- K+ inside: 150 mM

- K+ outside: 5 mM

- at rest: Na+/K+ pump- 3 Na+ out and 2 K+ in

What is the all or nothing principle?

If the neuron does not reach the threshold or required voltage, action potential will not occur.

What is the absolute refractory period?

When a neuron is unable to respond to another stimulus

What is the relative refractory period?

- When Na+ gates are closed and K+ gates are open

- The segment of the axon can potentially respond to a new stimulus but the stimulus must be have a greater magnitude to create the AP

What is the differences between efferent vs. afferent nerves?

- Afferent nerves are nerves that will send signals to the brain and or sensory nerves.

- Efferent are motor nerves that activate after the CNS sends a signal.

What is the order of an AP? (6 steps)

RMP--> Depolarization--> Overshoot--> Repolarization--> Hyperpolarization--> Returns to RMP

What happens during depolarization?

Voltage gated ion channels are opened by an electrical stimulus

What happens during repolarization?

- Na+ channels close and limits the amount entering the cell making the cell negative

- K+ channels open and K+ move out of the cell

What happens in hyperpolarization?

When the membrane potential is more negative the RMP

What is VO2max?

The best measurement of Maximal exercise capacity and cardiorespiratory endurance or aerobic fitness. Maximal Oxygen uptake

What is the length-tension relationship?

The baseline length correlating to the amount of force. Too short or too stretched out sarcomere will reduce the force production

Can AMP be used for energy?What is the role?

- AMP cannot be used as energy because of how strong the bond is

- helps with phosphorylase and PFK

What is Beta-oxidation?

the process of Converting fatty acids to Acetyl-CoA (Fat metabolism in Krebs cycle)

Which step represent the convergence of glycolysis and glycogenolysis?

Glucose-6-phosphate

What is the function of the axon hillock?

Determines if AP should occur

when is an action potential fired? How does this occur?

- Threshold at -50mV to -55mV

- dendrites are receiving stimulus

Compare/contrast the function of muscle spindles and GTO.

- Muscle spindles: Located in muscle belly (intramural fibers: are not contractile, extrafusal fibers: contractile); responds to stretch; stimulatory mechanism: enhances force; always working

- GTO(Golgi tendon organ): Located in the tendon; Responds to tension or strain; inhibitory (failing PR-> looks like throwing weight on ground): IPSP to agonist, EPSP to antagonist; lifting weights