Muscular System

What are the prefixes used to describe muscles?

Myo-

Mys-

Sarco-

Describe a muscle cell

• composed of elongated cells called muscle fibers

• Control movement by contracting and relaxing

where do we find smooth muscle cells?

lines hallow organs (visceral)

what is the main function of smooth muscle cells?

propel substances through internal body cannels (peristalsis)

are smooth muscles voluntary or involuntary?

involuntary

where do we find cardiac muscle cells?

form in the walls of the heart

what is the main function of cardiac muscle cells?

pump blood through body

are cardiac muscle cells voluntary or involuntary?

involuntary

where do we find skeletal muscle cells?

attached to bone

are they voluntary or involuntary

voluntary

what are the four functions of skeletal muscles

• Produce movement

• Maintain posture

• Stabilize joints

• Generate heat (body temp of 98.6)

• Maintain healthy metabolism

Which have situations and which don’t between smooth muscles, cardiac muscles, and skeletal muscles

Smooth: no

Cardiac: yes

Skeletal: yes

where do we find visceral smooth muscle?

The walls of hallow organs

what is peristalsis?

rhythmic waves of muscular contraction in the walls of certain tubular organs

what is an intercalated disc and what is the importance to a cardiac muscle cells?

• Connection between cardiac muscle cells

• Allow impulses so they travel rapidly from cell to curl, triggering contraction

Two characteristics of cardiac muscle cells are self-excited and rhythmic, cardiac muscle has the ability to…

cause the rhythmic contractions of the heart.

according to table 8.3, which muscle cell types are voluntarily controlled and involuntarily controlled?

involuntarly: smooth and cardiac

Voluntarily: skeletal

what is the difference between the origin and insertion point of skeletal muscles?

less movable end: origin

More movable end: insertion

describe the movement of the biceps

1. Two heads: one short and one long

2. Insertion: both heads merge and attach to radius bone

   1. Action: when these heads contract, they pull on the radius, causing forearm rotation and flexion at the elbow

how many nucleus do skeletal muscle cells have?

more than one

what is the major structural and functional component (macromolecule) of a muscle cell

• thin actin filaments

• Thin myosin filaments

That is the structure of a myofibril

• Actinmyosin

Bundles of proteins that overlap each other

One single muscle twitch consists of?

1. Stimulus (actin potential from nervous system)

2. Single contraction - each sarcomere contains filaments that slide

3. Single relaxation

What is a muscle contraction?

the sum of all the sarcomeres contracting at once

what is a neuromuscular junction

• junction of motor neuron and a muscle cell types

• Motor neuron and the muscle it activates is called a motor unit

• neuron passes electric impulses (called action potential) to muscle fiber causing the fiber to change shape

What is the sliding filament theory

• Explains how muscles contract

• Muscles shorten when actin slide past myosin

• Filaments do not shorten, they slide

• Myosin heads attach to actin and pull it inward

• ATP (energy) is required for the process

• Sliding causes the muscle to contract and create movement

What is the All or None principle and how is it different than a graded response?

All or none: applies to only muscle cells

Graded response: different degreees of shortening of whole muscle

• Produced:

• 1. Change frequency of stimulation (higher = stronger)

• 2. Change number of cells being stimulated (more = stronger)

what is the difference between an isotonic and isometric contraction

isotonic: shortens when contracted

Isometric: contracts without shortening

What is muscle tone?

always contracting happening

“Use it or lose it”

Explain aerobic

• endurance

• Blood supply to muscle increases

• More mitochondria produced

• Stronger more flexible muscles more resistance to fatigue

• Muscle wont increase in size

Explain Anearobic

• resistance or isometric

• Individual muscle cells enlarge

• Amount of CT increases (tendons / ligaments)

• Results in increased muscle size and strength

• Does not increase endurance

What is a muscle fiber

A single cell that contracts in response to stimulation and relaxes when stimulation is done

what are the two proteins that make up a myofibril

actin and myosin

the organization of the two proteins gives skeletal muscle its characteristic situations. These repeating pairs are called…

sarcomeres

what is another name for the endoplasmic reticulum used in muscle cells?

sarcoplasmic reticulum

what is a neuromuscular junction

synapse (connection) between a motor neuron and a skeletal muscle fiber

what is the sliding filament model of muscle contraction

includes all of these actin-myosin interactions and is named for how the sarcomers shorten

what is the role of ATP in muscle contraction

they supply the energy for it

what is rigor mortis

skeletal muscles partially contracting and becoming rigid several hours after death

what is the neurotransmitter responsible for stimulation of muscle contraction

acetylcholine

according to table 8.1 what are two major events of muscle contraction?

1. Contraction

2. Relaxation

What is some information of aerobic fitness?

What is “aerobic capacity”

• an activity you do that requires oxygen

• Dancing, bicycling, running

• how well you use oxygen

What is some information about muscular fitness?

What ensures overall muscular fitness?

• strength and endurance of your muscles

• Free weights, weight machines, resistance bands

• training that includes multiple training options

What is some information about flexibility?

What happens anatomically to your muscles when you increase flexibility?

• ability to move your joints throught their full range of motion

• yoga, tai chi, stretching

• lengthen muscles

What is some information about stability and balance?

What muscles are involved in stability and balance?

• activity associated with your bodys core muscles

• Core exercises

• lower back, hips, and pelvis

what are the three major benefits to weight training

1. Tone muscles

2. Improve appearance

3. Fight age-related muscle loss