Bell Ringer 1. What is the best way to build muscle WITHOUT using - PowerPoint Presentation

Slide1

Bell Ringer

1. What is the best way to build muscle WITHOUT using

perfomance

enhancing drugs?

2. Would

you consider supplements such as

Creatine

to be a performance enhancing drug? Why or why not?Slide2

The Muscular System

A&P Fall 2016Slide3

I. Overview of Muscle Tissues

Muscle Types

Skeletal Muscle

Muscle fibers are packaged together to form whole muscles

Muscles are striated (have stripes)

Controlled voluntarilySlide4

2. Smooth Muscle

a. Found in walls of hollow organs

i. Ex. Stomach, bladder, etc b. Has no striations c. Involuntary controlSlide5

3. Cardiac Muscle

a. Found only in the heart

b. Has striations

c. Involuntary controlSlide6

B. Skeletal Muscle Functions

1. Producing Movement

a. mobility of the body as a whole

2. Maintaining posture and body position a. continual tiny adjustments to maintain standing or sitting postureSlide7

3. Stabilizing Joints

a. muscle tendons reinforce joints where bones don’t fit together well

i. Ex. Shoulder joint 4. Generating Heat a. energy used for muscle activity creates heat 5. Protection

a. covers internal organsSlide8

II. Microscopic Anatomy of Skeletal Muscle

Myofibrils

Ribbon-like organellesSlide9

2. Made of chains of

sacromeres

Myofilaments

are substructures that produce light and dark banding patterns

i

. Thick filaments made of myosin proteinii. Thin filaments made of actin

proteinSlide10

3. Broken into many parts

Z disc

i

. Where

sacromeres

join togetherLight I bandSpace where no myosin protein is present

Dark A band

Space where myosin protein is presentSlide11

d. H zone

Space where

mysoin

IS present, but

Actin

is absente. M lineLocated within the H zoneProtein rods that hold adjacent myosin filaments togetherSlide12
Slide13

B. Muscle Fibers (Cells)

Have many

ocal

nuclei

Contain special organelles

Myofibrils Many in each cell

Take up most of the space in the cytoplasm

Sarcoplasmic

reticulum

Special ER that surrounds every myofibrilSlide14

3. Plasma membrane is called the

sarcolemma

Means “Muscle Husk”

4. Each cell enclosed in

Endomysium

a. A delicate connective tissue sheathSlide15

C. Fascicle

Formed by many muscle fibers bundled together

Surrounded by the

Perimysium

Another fibrous membrane

Coarser and stronger than the EndomysiumSlide16

D. Muscle Organ

Formed by many Fascicles bundled together

Surrounded by the

Epimysium

Toughest membrane of all

Also form tendons at the end of musclesSlide17
Slide18

III. Skeletal Muscle Activity

Stimulation & Contraction of a Single Muscle Cell

The Nerve Stimulus and the Action Potential

Motor Unit

Made of one neuron and multiple muscle cells

The nerve fiber branches into multiple axon terminalsSlide19
Slide20

b. Structure of Neuromuscular Junctions

Space between a neuron and muscle cell

Filled with vesicles that contain acetylcholine (

ACh

)

Acetylcholine is a neurotransmitterSlide21
Slide22

c. Action of neuromuscular junctions

Slide23
Slide24

2. The Sliding Filament Theory

a. Action potential within the

sarcolemma

causes calcium ions to be released into the cytoplasm

i. Ca2+ comes from the sarcoplasmic reticulum

b. Release of Ca2+ triggers the binding of myosin to

actin

Slide25

c. Myosin heads “

walk

” along

actin

filaments, causing

actin proteins to slide closer together i. Neither filaments actually shorten, they just slide past one anotherSlide26

B. Contraction of Skeletal Muscle as a whole

1. Graded Responses

a. The “all-or-none” rule applies to fibers

i

. means a fiber will always contract to its fullest extent when stimulated ii. Does NOT apply to the whole muscleSlide27
Slide28

b. Whole muscle can react with different degrees of shortening in 2 ways

i

. change the frequency of muscle stimulation

ii. Change the number of fibers being stimulated at one timeSlide29

2. Muscle Response to rapid stimulation

a. Complete Tetanus

i

. muscle contractions are completely smooth and sustained

ii. No evidence of relaxation Slide30

3. Muscle Fatigue and Oxygen Deficit

a. Muscle fatigue occurs when muscles are exercised strenuously

i

. Muscles are still being stimulated but are unable to contract

Slide31

b. Oxygen deficit most likely cause

i

. body is unable to take oxygen in fast enough

ii. Muscles do not get the amount needed to contract

iii. Lactic acid builds up as a resultSlide32

4. Types of Muscle Contraction

a. Isotonic

i

. the muscle shortens during contraction

ii. Ex. Bending your knee b. Isometric i. the muscle does NOT shorten ii. Ex. Straining to lift a heavy objectSlide33
Slide34

5. Muscle Tone

a. Some muscle fibers are still contracting at all times

i

. allows muscle to remain firm and healthy

ii. Exercise can increase muscle tone Slide35

b. Endurance exercises

i

. results in stronger, more flexible muscles that resist fatigue

ii. Ex. Jogging or biking

c. Resistance exercises i. increases muscle strength and size ii. Ex. Forcing a muscle to contract