Transcript Opening Assignment

Opening Assignment
1. What number is the
A. Diaphysis ______
B. Medullary cavity ________
C. Proximal epiphyses _____
D. Distal epiphyses ______
2. What are the
concentric circles
around a central canal
called?
3. What is the name of the blue
facial bone?
4. What suture connects the
frontal with the parietal bones?
5. What type of joint is this suture?
Intro to the Muscular System
 What
are the three types of muscle tissue?
 Pushing
the Limit: Strength
http://www.bing.com/videos/search?q=pushing+t
he+limit+strength&view=detail&mid=02088691688E
9D0BC79F02088691688E9D0BC79F&FORM=VIRE1
Opening Assignment

What are 2 things you learned while watching the
video Wednesday (Pushing the Limit: Strength)

List the three types of muscle tissue and give an
example of where it is found in the human body.
Anatomy and
Physiology
Honors
Chapter 8 The
Muscular System
BY MRS. SHAW
Learning Goals
Students will be able to

Describe how connective tissue is part of the skeletal muscles.

Name the major parts of the skeletal muscle fiber and describe their
function.

Explain the events that occur with skeletal muscle fiber contraction.

Explain how the muscular system functions to help maintain
homeostasis within our bodies.

Identify the superficial muscles of the anterior and posterior human
body.
Did you know that ?
-
more than 50% of body weight is muscle!
-
And muscle is made up of proteins and water
8.1 Introduction

Muscles are responsible for all types of
movements in our body both voluntary
and involuntary.

3 types of connective muscle tissue that
enable this movement are
 Smooth muscle tissue: found in the GI
tract
 Cardiac muscle tissue: found in the
heart
 Skeletal muscle tissue: found attached
to skeletal bones
Three types of muscle
Skeletal and
smooth muscle
cells are
elongated
(muscle cell =
muscle fiber)
All muscles share some
terminology
Prefixes myo and mys
refer to “muscle”
Prefix sarco refers to
“flesh”
Skeletal
Cardiac
Smooth
8.2 Structure of a Skeletal Muscle

A skeletal muscle is an organ of
the muscular system composed
of skeletal muscle tissue, nervous
tissue, blood tissue, and other
connective tissues.
Connective Tissue Coverings

Layers of fibrous connective tissue
called fascia separate and
individual skeletal muscle from
adjacent muscles and hold it in
position.

Tendons are cordlike projections of
this fascia that intertwine with a
bones periosteum to attach to it.
Connective Tissue Coverings

The layer of connective tissue that
surrounds the skeletal muscle is called
epimysium.

Perimysium extend inward from the
epimysium and separate the muscle tissue
into small compartments.

Fascicles are bundles of skeletal muscle
fibers.

Each muscle fiber within a fascicle has a
thin covering called the endomysium.
Skeletal Muscle Fibers

A skeletal Muscle fiber is a single cell that contracts in
response to stimulation and then relaxes when the
stimulation ends.

Each muscle fiber is a thin, elongated cylinder with
rounded end.

Beneath the cell membrane (or sarcolemma) is the
cytoplasm (or sarcoplasm) where many nuclei and
mitochondria are located.

Why would skeletal muscles have multiple
mitochondria?
Muscle Structure
Muscle
Fascicles
Muscle Fibers (cells)
Myofibrils
Thick and Thin Filaments
Myofibrils and Muscle Contraction

Myofibrils are composed of
two main types of protein
filaments:
 Myosin
 Actin
– thick fibers
– thin fibers
The organization of these
filaments give the striations
their light and dark
appearance.
How a Muscle Contraction is Signaled.

The sarcoplasmic reticulum is similar to the
endoplasmic reticulum and functions to store
and release calcium ions.

The transverse tubules opens the calcium
release channels within the sarcoplasmic
reticulum so that it can be used to initiate
muscle contraction.

https://www.youtube.com/watch?v=CepeYFvq
mk4
Sarcomeres

Sarcomeres are structural units within a
myofibril of striated skeletal muscle.

The two main parts of the sarcomere are
the

Light sections called l bands consisting of
thin actin filaments attached to structures
called Z lines.

The dark sections are called A bands
and consist of thick myosin filaments
overlapping thin actin filaments.
Crash Course - Muscles
Worksheet time

Complete worksheet #1 due on Monday.

Monday we will go over these first few slides
again and then move into the anatomy of a
Neuromuscular junction and the physiology of a
muscle contraction.
Opening Assignment – turn in worksheet #1
1.
What is a tendon? A ligament?
2.
What is the difference between tendonitis and
tenosynovitis?
3.
Put the following terms in order from largest to smallest
Muscle fiber
fascicle
Myosin filaments
myofibril
actin filaments
muscle
Neuromuscular Junction

Motor neuron – each skeletal
muscle fiber (cell) connects to
an axon from a nerve cell
called a motor neuron.

This axon extends outward
from the brain or spinal cord
and this muscle fiber only
contracts when the motor
neuron stimulates it to do so.
Neuromuscular Junction

Neuromuscular junction: the
area where the motor neuron
connects with the muscle fiber.

Motor end plate: the area of the
muscle fiber membrane that is
specialized with abundant
nuclei and mitochondria to
enable the connection with the
motor neuron.
Neuromuscular Junction

The end of the motor neuron branches out and
projects into the recesses of the muscle fiber
membrane. The cytoplasm at the distal ends of
these motor axons is rich in mitochondria and
contain tiny vesicles that store chemicals called
neurotransmitters.

Neurotransmitters are chemical messages from
the brain that signal a reaction in your body. For
example there are neurotransmitters that tell your
heart to beat and your lungs to breathe. They
also can change your mood like with Serotonin.
Neuromuscular Junction

When a nerve impulse comes
down it signals the release of these
vesicles with neurotransmitters into
the synaptic cleft between the
neuron and the motor end plate.
This action stimulates the muscle
contraction.
Motor Unit
A Motor Unit is the
combination of a motor
neuron and all the muscle
fibers that it controls.
Neuromuscular Junction
Label this Neuromuscular Junction
1. _Motor neuron_____________________
2. _Axon branches___________________
3. __Muscle fiber nucleus_____________
4. ___Motor end plate________________
5. ___Myofibril of muscle fiber_________
6. ___Mitochondria___________________
7. __Synaptic vesicles________________
8. __Acetylcholine__(neurotransmitter)
9. ___Folded Sarcolemma____________
10. __Synaptic cleft____________________
Neuromuscular Junction Video
Check for Understanding
1.
The area where the motor neuron and the muscle fiber meet to communicate is the
___________________________________________.
2.
The specialized region of the muscle fiber that has folded sarcolemma and many
mitochondria is the ________________________________.
3.
A chemical that is released from the vesicles within the motor neuron when an
action potential stimulates it is a ______________________________.
4.
The area where these chemicals are released into is the ________________________.
Homework

Read section 8.3 and take notes on pages 173 – 176 up to
Oxygen supply and Cellular respiration.

On Wednesday we will review this section and add to your notes
if needed. I will also give you another worksheet to review 8.3
again.

Friday will be an open notes quiz on sections 8.1- 8.3
Opening Assignment

Copy these and put these steps in order from what happens first to what happens last.
Steps of Stimulation for Muscle Fiber Contraction
_________An elevation of Calcium levels within the axon branches stimulates synaptic vesicles to
release the neurotransmitter acetylcholine into the synaptic cleft.
_________The brain or spinal cord sends an action potential down the motor neuron to the axon
branches.
_________The action potential stimulates calcium to enter the axon branches of the motor neuron.
_________The increase in acetylcholine into the synaptic cleft causes chemical changes that
stimulate a muscle contraction within the myofibril.
Neuromuscular Junction
Label this Neuromuscular Junction
1. __________________________________
2. __________________________________
3. __________________________________
4. ___Motor end plate________________
5. ___________________________________
6. ____________________________________
7. ____________________________________
8. __Acetylcholine__(neurotransmitter)
9. ___________________________________
10. __Synaptic cleft____________________
8.3 Skeletal Muscle Contraction

A muscle contraction

complex mechanism that involves the
movements of myosin and actin within a
myofibril

These microfilaments slide past each other
causing the muscle fiber to shorten in length
(contract).

The effect causes pulling on the tendons they
are attached to and eventually movement
of the skeletal bones.
Skeletal Muscle Contraction

Myosin is composed of two twisted
protein strands with globular parts
called cross bridges projecting
outward.

Actin is composed of a globular
structure with a binding site in a
double helix configuration.

Troponin and tropomyosin are the
protein protectors of actin. They move
aside when a muscle impulse occurs.
Cross
bridge
Skeletal Muscle Contraction

Remember that the transfer of an action potential
down a motor neuron will cause acetylcholine to be
released into the synaptic cleft.

This release causes the transfer of that nerve impulse
into the muscle fiber becoming a muscle impulse.

This impulse passes all along the muscle fiber causing
calcium ions located within the sarcoplasmic reticulum
to be released and travel through the transvere tubules.

When this calcium gets to the sarcomere it causes the
troponin and tropomyosin to move aside and expose
the actin binding sites.
Simplified Muscle Contraction Steps
Simplified Steps of a Muscle Contraction:
1. Myosin cross bridge attaches to the
actin binding site.
2. Working stroke – the myosin head
pivots and pulls the actin filament
toward the M line.
3. ATP attaches to the myosin head to
cause the cross bridge to detach.
4. ATP will split into ADP(stored energy)
and Phosphate which will cause the
myosin head to cock again.
What it looks like at the Sarcomere level
Energy for Contraction

ATP molecules supply the energy for a muscle fiber
contraction.

A muscle fiber only has enough ATP for a short contraction so
it must constantly be regenerating it from ADP and
phosphate.

Creatine phosphate makes this regeneration possible as it
contains high energy phosphate bonds and is 4-6x more
abundant in muscle fibers than ATP.
Crash Course – Muscle Contraction

https://www.youtube.com/watch?v=KtvCaOt6UQ
Fridays Open Notes Quiz will cover
1.
3 types of muscles and examples
2.
Structure of a muscle – levels from Muscle to actin filaments
3.
Steps for stimulation of muscle fiber
4.
Sarcomere anatomy
5.
Steps for contraction of a muscle
6.
Energy for a contraction
**You can bring both worksheets and all notes – this quiz is meant
to help you, not hurt your grade.
Opening Assignment
1.
What role does Calcium play in a muscle contraction?
2.
Label the sarcomeres below with the sarcomere length, Z
lines, myosin, actin, and then say which one shows a
muscle contraction and which one shows a relaxation.
Muscle Song Video Requirements

Your video must include a least 15 of the Superficial
muscles located on pages 184-185.

You must have a music background.

You can create your own lyrics or use some from the
internet.
Opening Assignment

Today we will watch your muscle music videos so make sure you have sent me the link! Best
video wins doughnuts!
1.
What organelle is responsible for making the ATP necessary for a muscle contraction?
2.
Let’s review again! Label the sarcomeres below with the sarcomere length, Z lines, myosin,
actin, and then say which one shows a muscle contraction and which one shows a relaxation.
Your videos!

Team Macarena! https://www.youtube.com/watch?v=2D_Q-598k

Team Bieber! https://www.youtube.com/watch?v=jdaULgoQyaQ&feature=youtu.be

Team Shorty: https://www.youtube.com/watch?v=DbtHRRPU6Y0&feature=youtu.be

Pumped Up: