exam 4 study!

Endomysium definition:

connective tissue around muscle cell

Perimysium definition:

connective tissue around muscle fascicle

Epimysium definition:

connective tissue surrounding entire muscle

Tendons do what?

attach between muscle and bone matrix

What are all the components of muscle tissue?

periosteum covering the bone, tendon, fascia, skeletal muscle, epimysium, perimysium, fasciculus, endomysium, muscle fiber

(the muscle fiber portion) Sarcolemma definition:

plasma membrane of a muscle fiber

(the muscle fiber portion) Sarcoplasm definition:

cytoplasm of a muscle fiber

(the muscle fiber portion) Myofibrils definition:

long protein cords occupying most of the sarcoplasm

(the muscle fiber portion) Sarcomere definition:

a functional contractile unit

(the muscle fiber portion) Multiple nuclei definition:

flattened nuclei pressed against the inside of the sarcolemma

(the muscle fiber portion) Mitochondria definition:

packed into spaces between myofibrils

(the muscle fiber portion) Sarcoplasmic reticulum (SR) definition:

smooth ER that forms a network around each myofibril

(the muscle fiber portion) Terminal Cisterns definition:

dilated end-sacs of SR which cross the muscle fiber from one side to the other

(the muscle fiber portion) Sarcoplasmic reticulum acts as a what?

calcium reservoir, releases calcium through channels to activate contraction

(the muscle fiber portion) T tubules definition:

tubular unfoldings of the sarcolemma that penetrate through the cell and emerge on the other side

(the muscle fiber portion) Triad definition:

a T tubule and two terminal cisterns associated with it

Calcium is strength to what?

muscle contraction

Sarcomere definition:

segment from Z disc to Z disc, functional contractile unit of muscle fiber

Muscles cells shorten because their ________________

individual sarcomeres shorten

Z disc (Z lines) are pulled closer together as ______________

thick and thin filaments slide past each other

Neither thick or thin filaments change length during _______________

shortening, only the amount of overlap changes

Thin filaments ----> _________

Actin

Thick filament -----> __________

myosin

Sarcomere shortening -----> ____________

muscle shortening

For contraction of the muscle, the electrical pulse travels down the _________, causing the release of CA2+ (___________) from the SR

T-tubule, calcium ions

Nothing can happen for contraction until what is released?

Calcium

How does a skeletal muscle (Sarcomere) shorten?

Cross bridge cycle

What is the cross bridge cycle?

myosin head forms a crossbridge with actin

Actin is ________

myosin connection

Tropomyosin and troponin work together to do what?

block the myosin binding sites on actin

When a calcium ion binds to troponin, the tropomyosin complex moves, which ____________

exposes myosin binding sites

Nerve cells whose cell bodies are in the brainstem and spinal cord that serve skeletal muscles

Somatic motor neurons

their axons that lead to the skeletal muscle. Each nerve fiber branches out to a number of muscle fibers. Each muscle fiber is supplied by only one motor neuron.

Somatic motor fibers

Motor neurons and motor units definition:

a motor unit is a motor neuron and all the muscle fibers it activates

(neuromuscular junction) Synapse definition:

point where a nerve fiber meets its target cell

(neuromuscular junction) Each terminal branch of the nerve fiber within NMJ forms a separate synapse with the muscle fiber consisting of:

Axon terminal, Synaptic vesicles with Acetylcholine, synaptic cleft

Synaptic cleft definition:

gap between axon terminal and sarcolemma

Involves the release of neurotransmitters from presynaptic neurons and its detection by specific ligand-gated ion channels at the surface membrane of postsynaptic neurons, (this binds ion channels to allow potassium into the bone cell):

Synaptic transmission

Acetylcholinesterase (AChE) definition:

breaks down ACh, allows relaxation of muscles

Binding of _________ to its receptor make membrane more permeable to ______

AChE, Na+

How do motor neurons control the strength of muscle contraction?

Strength of contraction depend on initial length, stimulation rate of motor neuron and number of motor neuron stimulated.

Strength of muscle contraction depends on:

initial length=actin/myosin overlap, number of motor units=whole or partial contraction, rate of motor neuron firing=impacts intercellular CA++

Motor neurons generally stimulate the muscle ______ ________ during a single contraction.

many times

Effort between the resistance and the fulcrum (REF), most joints of the body, the effort of a biceps curl is applied to the forearm between the elbow joint (fulcrum) and the weight in the hand (resistance):

Third-class lever

(LEVERS) Force 1 x Distance 1= __________

Force 2 x Distance 2

Twitch contraction definition:

a single stimulus is delivered; the muscle contracts and relaxes

Wave summation definition:

stimuli are delivered more frequently, so that muscle does not have adequate time to relax completely and contraction force increases

unfused (incomplete) tetanus definition:

more complete twitch fusion occurs as stimuli are delivered more rapidly

fused (complete) tetanus definition:

a smooth continues contraction without any evidence of relaxation

Types of contractions:

isotonic contraction, concentric contraction, eccentric contraction

Isotonic contraction definition:

tension rises until muscle length changes, then remains constant. Same force.

Example of Isotonic contraction:

lifting an object, running, walking

Concentric contraction definition:

muscle tension overcomes load and muscle shortens, speed of contraction inversely related to load. Shortens.

Eccentric contraction definition:

when load is more than peak tension produced, muscle lengthens. Rate of elongation varies with difference in load and tension. Muscle elongates.

Isometric contraction definition:

Muscle length does not change and tension never exceeds load. No change in muscle.

Origin definition:

attachment point remains stable, doesn't move much when muscle contracts. Relative to insertion.

Insertion definition:

attachment point that moves when the muscle contracts. Usually further from origin. Insertion is attached to bone by tendons, has less muscle mass than origin.

Synergist definition:

assists the primary mover (agonist) muscle

Antagonist definition:

opposes the agonist muscle

Sternocleidomastoid, scalene, pectoralis, serratus, diaphragm, external intercostal muscles, internal intercostal muscles, transversus thoracis muscle, external oblique muscle, rectus abdominis, internal oblique muscles:

muscles of respiration

orbicularis, buccinator, temporalis, masseter:

muscles of head and neck

Serratus Anterior function:

provides stability for shoulder joint

Insertion of serratus anterior:

Scapula

Origin of serratus anterior:

ribs

Action of serratus anterior:

scapula abduction and outward rotation

Favorable place to listen to breath sounds because it has relatively few and thin muscular layers:

triangle of auscultation

Sternocleidomastoid, deltoid, pectoralis major, sternum, biceps brachii, subclavius, clavicle, subscapularis, pectoralis minor, coracobrachialis, serratus anterior, humerus:

shoulder muscles

Tricep Brachii origin:

scapula and humerus

Triceps Brachii action:

elbow extension, shoulder extension

Rectus femoris origin:

anterior inferior iliac spine

rectus femoris insertion:

base of patella to form central portion of quadriceps femoris tendon

rectus femoris action:

extends the knee and flexes the hip

rectus femoris innervation:

femoral nerve

Nerve cells use glucose as what?

primary energy source

Different __________ are absorbed from digestive tract: fructose, galactose, and ______

monosaccharides, glucose

Glucose is broken down into CO2, H20, and _______ when needed

energy

Excess glucose is converted into _________ by ________ and stored in the ______ and muscle cells

glycogen by glycogenesis and stored in the liver

Lipids definition:

organic compounds that include fats, oils, phospholipids, and cholesterol

mainly supply energy for cellular processes, contains more than twice as much chemical energy per gram as carbohydrates or proteins, glycerol and fatty acids can be used to synthesize storage fats in adipose tissue, excess glucose or amino acids can also be converted into fat molecules

lipids functions

Triglycerides definition:

glycerol and 3 fatty acids

Triglycerides function:

dietary lipids, also called fats

Protein sources FOOD:

meat, fish, poultry, cheese, nuts, milk, eggs

Legumes (beans and peas) contain more or less protein?

Less

The body needs how many of what to synthesize proteins?

20 types of amino acids

(20 types of amino acids) ___ can be synthesized by the body; called non-essential amino acids. But, ___ cannot be synthesized called ______ amino acids, essential amino acids are not stored in the body.

12 can, 8 cannot, essential amino acids

Complete proteins:

high-quality proteins have good amount of essential amino acids for good health found in meat, milk and eggs

Incomplete proteins:

low quality proteins, do not contain adequate amounts of essential amino acids, found in many plant proteins

Certain combination of plant proteins like _______ and rice can provide adequate diversity of dietary amino acids

beans

8 essential amino acids cannot be synthesized by _______ cells and must be provided in the ______

human cells and must be provided in the diet

Energy values of foods:

calorie, kilocalories, caloric content

Calorie:

amount of potential energy a food contains, calories are units of heat

One _______ (1 kcal or 1000 calories) is the amount of heat ( ______ ) needed to raise the temperature of ______ kg of water by ______ degree Celsius

kilocalorie, energy, one kg, one degree

Calorie content:

foods can be measured by a bomb calorimeter

Caloric content of various types of nutrients:

carbohydrates, proteins, lipids

(caloric content) Carbohydrates:

4.1 calories/gram

(caloric content) Proteins:

4.1 calories/gram

(caloric content) Lipids:

9.5 calories/gram

Energy balance:

exists when caloric intake from food equals caloric output from BMR and muscular activities, body weight remains constant

Positive energy balance:

caloric intake exceeds output, tissues store excess nutrients, leads to weight gain

Negative energy balance:

caloric expenditure exceeds intake, tissues are broken down for energy, leads to weight loss