ANAPHY 100 MT LEC- Muscular System

Muscles

responsible for all types of body movement

Skeletal, Cardiac, Smooth

Enumerate the three basic muscle types:

Produce movement; Maintain posture; Stabilizing joints; Generating heat

Enumerate the functions of muscles

Attached to bones, or to skin (for facial muscles)

state the body location of skeletal muscles

walls of the heart

state the body location of cardiac muscles

in walls of hollow visceral organs

state the body location of smooth muscles

single, long, cylindrical, peripheral multinucleate cells with striations

state the cell shape and appearance of skeletal muscles

branching chains of cell, uninucleate, striations, with intercalated discs

state the cell shape and appearance of cardiac muscles

single, fusiform, uninucleate, no striations

state the cell shape and appearance of smooth muscles

Epimysium, perimysium, and endomysium

enumerate the connective tissue components of a skeletal muscle

endomysium attached to fibrous skeleton of heart

enumerate the connective tissue components of a cardiac muscle

endomysium

enumerate the connective tissue components of a smooth muscle

voluntary, via controls of nervous system; slow to fast; no

state the regulation, speed, and rhythmic contraction for a skeletal muscle

involuntary, with pacemaker, nervous system controls, hormones; slow; Yes

state the regulation, speed, and rhythmic contraction for a cardiac muscle

involuntary, nervous system controls, hormones, stretch; very slow; yes in some

state the regulation, speed, and rhythmic contraction for a smooth muscle

Skeletal Muscle

• Attached to bones by tendons • Multinucleated, striated, voluntary • Long cylindrical cells = muscle fibers • Contracts rapidly but tires easily

Smooth Muscle

• Found in walls of hollow organs (e.g. Stomach, intestines, blood vessels) • Non-striated, involuntary • Spindle-shaped cells, single central nucleus • Slow sustained contractions

Cardiac Muscle

• Found only in the heart • Striated, single nucleus, branched, involuntary • Cells connected by intercalated discs for coordinated contraction • Auto-rhythmic due to pacemaker cells

Muscle Functions

• Movement: locomotion, manipulation of environment • Posture maintenance • Joint stabilization • Heat generation (via ATP use in contractions)

Tendon

rope-like connective tissue connecting muscle to bone

Aponeurosis

sheet-like connective tissue

Endomysium

connective tissue that surrounds individual muscle fiber

Perimysium

connective tissue that surrounds a fasicle

Fasicle

a bundle of fibers

Epimysium

connective tissue that surrounds a whole muscle

Fascia

outer layer separating muscles from skin or other muscles

Muscle fiber:

long, cylindrical cell with multiple peripheral nuclei, containing myofibrils

myofibrils

composed of repeating units called sarcomeres

Sarcolemma

plasma membrane of the muscle fiber

Sarcoplasm

cytoplasm with myoglobin and mitochondria

Sarcoplasmic reticulum

stores calcium ions needed for contraction

Transverse (T) tubules

conduct impulses deep into the muscle fiber

Myofilaments

are protein filaments which make up myofibrils

Actin (thin)

anchored to Z discs, contain binding sites for myosin

Myosin (thick)

have heads that form cross-bridges with actin during contraction

Sacromere

the functional unit of contraction in a muscle

Z lines; I band; A band; H zone; M line

enumerate the main features of a sacromere

Z lines

boundaries of sarcomeres

I band

light band with actin filaments

A band

dark band with overlapping actin and myosin

H zone

lighter region in the middle of the A band

M Line

center of the H zone, holds myosin filaments together

Neuromuscular Junction

Site where a motor neuron communicates with a muscle fiber

Acetylcholine (Ach)

the neurotransmitter released into the synaptic cleft

Binding of Ach to receptors on the sarcolemma

Action potential is initiated through the:

1. Action potential reaches axon terminal of the motor neuron
2. Calcium channels open, allowing calcium into the axon terminal
3. calcium entry causes the synaptic vesicles to release acetylcholien through exocytosis
4. acetylcholine diffuses the synaptic cleft and binds to receptors in the sarcolemma
5. ACh binds and channels open, allowing sodium in the muscle fiber, potassium out the muscle fiber. causing a change in electrical condition (depolarization)
6. enzyme Acetylcholinesterase breaks down the Ach

state the process of neuromuscular junction

SPACE FOR SLIDING FILAMENT THEORY

SPACE FOR SLIDING FILAMENT THEORY

SPACE FOR ROLE OF CALCIUM

SPACE FOR ROLE OF CALCIUM

Isotonic Contractions (Concentric and Eccentric), Isometric Contractions

Enumerate the types of muscle contraction

Isotonic contractions

Muscle changes length to produce movement

Concentric Contraction

A type of contraction wherein the muscle shortens

Eccentric

A type of contraction wherein the muscle lengthens while contracting

Muscle Tone

Slight, continuous contraction even at rest

Twitch

Single brief contractions that are not normally seen in full muscles

Tetanus

Rapid stimulation causing sustained contractions

Stored ATP, Creatine Phosphate, Anaerobic Glycolysis, Aerobic Respiration

Enumerate the sources of ATP

Stored ATP

Creatine Phosphate

Anaerobic Glycolysis

Aerobic Respiration

Muscle Tone

a slight, continuous contraction of the muscle even at rest

Twitch

a single brief contraction that is not fully seen in muscle

Tetanus

a rapid stimulation of the muscle, resulting in continuous contraction

Stored ATP, Creatine Phosphate, Anaerobic Glycolysis, Aerobic Glycolysis

Enumerate the different sources of ATP

Stored ATP

a limited supply of atp

Creatine Phosphate

Regenerates ATP quickly, but is short term

Anaerobic Glycolysis

Glucose turns into lactic acid, quick but inefficient

Aerobic Respiration

Most efficient, requeires oxygen, occurs in the mitochondria

Direct Phosphorylation, Anaerobic Pathway, Aerobic Pathway

Enumerate the ways of regenerating ATP during Muscle Activity

Direct Phosphorylation

A coupled reaction of creatine phosphate (CP) and ADP

Direct Phosphorylation: Creatine Phosphate (CP) None 1 ATP per CP, creatine 15 seconds

enumerate the Direct Phosphorylation Enery Source: Oxygen Used: Products: Duration of enery provision:

Anaerobic Pathway

Glycolysis and Lactic Acid Formation

Anaerobic Pathway: Glucose None 2 ATP per Glucose, Latic Acid 40 seconds +

enumerate the Anaerobic Pathway Enery Source: Oxygen Used: Products: Duration of enery provision:

Aerobic Pathway

Aerobic cellular respiration

Aerobic Pathway: Glucose, Pyruvic Acid, Fatty free acids, amino acids Required 32 ATP per glucose, CO2, H20 Hours

enumerate the Aerobic Pathway Enery Source: Oxygen Used: Products: Duration of enery provision:

Muscle Fatigue

This is caused by depletion of ATP, Accumulation of Lactic acid, and Ionic Imbalances

Aerobic (Endurance) Excercise

• Increases capillaries, mitochondria, myoglobin
• improves stamina and heart health

Resistance (Anaerobic) Excercise

• causes hypertophy (increased muscle fiber size)
• improves strength and power

Aerobic (Endurance) Excercise Resistance (Anaerobic) Excercise

Enumerate the types of excercises

Muscle Dystrophy, Myasthenia Gravis

Enumerate the types of Muscle Disorders

Muscle Dystrophy

• Genetic, Progressive muscle degeneration
• duchenne muscular dystophy (DMD) is most common in males

Myasthenia Gravis

• Autoimmune Disease: Antibodies block Ach receptors
• leads to muscle weakness, especially facial and respiratory muscles

Flexion, Extension, Hypertension, Rotation, Abduction, Adduction, Circumduction, Dorsiflexion, Inversion, Supination, Opposition

Enumerate the types of Body Movements

Flexion

generally in the sagittal plane, decreases the angle of the joint and bring two bones closer together

Extension

Movement that increases the angle, or the distance between two bones

Hyperextension

extension that is greater than 180 degrees

Rotation

Movement of a bone around its longitudinal axis

Abduction

Moving limbs away from the midline

Abduction

Fanning movement of the fingers or toes when they spread apart

Adduction

Movement of limb toward the body midline

Circumduction

combination of flexion, extension, abduction, and adduction

Dorsiflexion

standing on your heels

Plantar Flexion

pointing the toes

dorsiflexion and plantar flexion

up and down movements of the foot at the ankle

Inversion

turning the sole medially

Eversion

turning the sole laterally

Supination

turning backwards

Pronation

turning forward

supination and pronation

refer to movements of the radius around the ulna

Opposition

in the palm of the hand, the saddle joint between metacarpal 1 and carpals allows the opposition of the thumb