Human phisology Exam III

What are the muscle types

Smooth, Cardiac, Skeletal

What is the shape of smooth muscle fibers

Cylinders with pointed ends; Uninucleated; Parallel lines, forming sheets

Where are smooth muscle located

walls of hollow internal organs and blood vessels

What are the Involuntary muscles

Skeletal, Smooth, Cardiac

What are the Voluntary muscles

Skeletal

What muscle is under control of autonomic nervous system

Smooth Muscle

Cardiac Muscles are

Uninucleated, striated, and tubular; Branched, interlock at intercalated disks

How do cardiac muscles avoid fatigue

They relax completely between contractions which, prevents fatigue

What is contraction

Rhythmic, involuntary tensing of the cardiac muscle without nervous stimulation

What is the shape of skeletal muscles

Tubular, multinucleated, and striated; long; run the muscle length

What is the structural order of the skeletal muscle: Periosteum covering bone → Tendon → Fascia →

Skeletal Muscle → Epimysium → Perimysium → Muscle Fascicle → Endomysium

What is the Muscle fascicle divided into

Endomysium→ Nuclei & Striations → Sarcolemma → Sarcoplasm → Myofibrils → Myofilaments

What is a Sarcolemma

Plasma membrane

What is a Sarcoplasm

Cytoplasm

What is a Sarcoplasmic reticulum

Endoplasmic reticulum

I Bands

Light Bands

A Bands

Dark bands

H Bands

Central band of A band

Z-lines (Discs)

Dark lines in the middle of the I bands

1

Z disks

2

H band

3

Thick Filaments

4

Thin filament

5

I band

6

A Band

7

Sarcomere

What contains all the thick filaments

A bands

What only contains thin filaments

I bands

What are the center of the A band

H bands

What are found in the center of each I band

Z discs

What is a sarcomere

Basic subuint of striated muscle contractions

Area from z disc to z disc

3 dimensional hexagon

Sliding Filament Theory

When a muscle contracts, sarcomeres shortens

Sliding Filament Theory

A bands

Dont shorten; move closer together

Sliding Filament Theory

I Bands

Shorten; thin filaments do not

Sliding Filament Theory

H bands

Thin filaments slide over; Disappears

Thin Filament Protein

Actin; proteins called Tropomyosin & Troponin that prevent myosin binding at rest

Thick Filament protein

Myosin; Has two globular heads with actin-binding sites and ATP binding sites

What causes the shortening of the myofibrils

Shortening of the sarcomeres- Distance between z lines are reduced

How is the sarcomeres shortening accomplished

by sliding of myofilaments- length remains untouched

What produces the sliding

asychronous power strokes

What happens to the A band

same length, but pulled towards origin of muscle; pulled together as I bands shorten

Cross bridges

Linking of thick and thin filaments

300-400 globular -___ subunits arranged in a double row and twisted to form a helix

Actin

What physically blocks cross bridges

Tropomyosin