Download muscular system

MUSCULAR SYSTEM
Topics for Oral Report:
• Muscular contraction (5 members)
• Fatigue (5 members)
• Diseases of muscles (5 members)
Functions:
• Body movement
• Maintenance of posture
• Respiration
• Production of body heat
• Communication
Characteristics of Muscle
Tissues:
• Irritability or Excitability – capacity to respond
to stimulus
• Extensibility – can be stretched after it contract
• Elasticity – ability to return to its original resting
length after the force has been
removed
• Contractility – ability of the muscle to shorten,
thicken or contract
General Classes of Vertebrate
Muscles:
1.
Involuntary muscles
2.
Voluntary muscles
Involuntary or smooth muscles

Walls of digestive tract and other viscera

Originate from the
transformation of
mesenchyme cells
of splanchnic
mesoderm
Voluntary or striated muscles
• Arise from the myotomes (muscle plates)
Two kinds:
a. parietal or somatic muscles – arise from
myotomes – cover most of the body
b. branchial muscles – arise from hypomere
– gill region and innervated by cranial
nerves
Types of vertebrate muscles:
1.
Skeletal muscle
2.
Smooth muscle
3.
Cardiac muscle
Connective tissue associated
with skeletal muscles
1. Epimysium (fascia) – tough connective that
covers the entire muscle
Strong, cordlike epimysia are called tendons.
Sheet-like epimysium is called aponeurosis.
2. Perimysium – wraps the bundle of fibers
called fascicle
3. Endomysium – encloses each muscle fiber
wraps the bundle of fibers
called fascicle
(fascia) – tough connective
tissue that covers
the entire muscle
encloses each
muscle fiber
Molecular Structure of a Muscle
Fiber
1. Sarcolemma – thin, elastic, tough sheath or
membrane covering of a muscle fiber
2. Sarcoplasm – semi-fluid ground substance
or matrix where myofibrils are suspended
Components of Sarcoplasm:
a.
Fluid containing large quantities of K, Mg, PO4,
protein enzymes, mitochondria
b.
Two sets of separate tubules that are functionally
related systems:
* Sarcoplasmic reticulum or ER of the muscle cell –
consists of longitudinal tubules that lie parallel to the
myofibrils
* T-tubule or transverse system – deep
invaginations or indentation of the sarcolemma into
the interior of the muscle fiber
Chemical Composition of Muscle
Tissue:
• 75% - water
• 20% - protein (actin and myosin)
• 5% - made up of:
* carbohydrates – glycogen and glucose
* non-nitrogenous substances –
ATP and posphocreatine
* inorganic salts
* lipids
Parts of Skeletal Muscle:
1. Origin – end of muscle is fixed to the
immovable or less movablebone
2. Insertion – the end part is attached to a
freely movable bone
3. Belly - portion of the muscle between
the origin and the insertion
How Skeletal Muscles Are Named
1. Location: some are named for the bone with
which they are associated
- between the ribs – intercostal muscles
- region of the arm – brachi
- behind the tibia – tibialis posterior
- in the chest – pectoralis or pectus
2. Action:
- lifter – flexor
- extensor
- abductor – move away
- adductor – move towards the body
- elevator
3. Division (no. of heads):
2 heads – biceps (arm)
3 heads – triceps (back of arm)
4 heads - quadriceps
4. Point of attachment:
- coccygio-sacralis
- sterno-radialis
- zygomaticus (smiling muscle)
- temporalis
- nasalis
5. Direction of muscle fibers (orientation of
fibers):
- straight/parallel to the body or limb rectus
- across – transversus
- oblique (slant)
- lateral - lateralis
• Oblique
• Lateralis - lateral
6. Shape:
- trapezoid – trapezius
- triangular – deltoid
- rhomboid – rhomboideus
(connects scapula
to the spinal column)
7. Size:
- large – maximus, magnus, major (Gluteus
maximus – buttock)
- smaller – minimus
- long – longus
- longest - longissimus
Size
- short – brevis (muscle of the hand)
- slender – gracilis
(medial side of the thigh)
- widest - latissimus
8. Relative position:
- lateral
- medial
- internal
- external
Major types of muscles based on
fiber arrangement (Muscle Architecture)
1. Parallel – long excursions, straplike muscles
* contract over a great distance and good
endurance
* not esp. strong
- sartorius (thigh)
- rectus abdominis
2. Convergent – fan-shaped muscles
* fibers covers at the insertion point
to maximize contraction
- deltoid
- pectoralis major
3. Pennate - many fibers per area
* broad origin and insertion
* provide dexterity
* allow better stabilization and force
production but less flexilibilty
* very strong muscles
*generally tire quickly
Kinds of pennate muscles:
a. Unipennate
(extensor digitorum)
c. Multipennate
b. Bipennate
(rectus femoris)
c. Multipennate
– deltoid muscle
(arm abduction)
- gastrocnemius
- latissimus dorsi
( swimming, punching)
- pectoralis (sternal head)
4. Sphincter – muscles that surround a
body opening, or orifice
* closes the opening
- orbicularis oculi
- orbicularis oris (kissing muscle)
- anus
Muscle actions - antagonistic

Extensors –extend one part

Flexors - bend one part of the skeleton
more than the other

Adductors – draw an appendage toward
the midline of the body

Abductors – move the appendage away
from the midline of the body

Elevators – elevate a part

Depressors – lower a part

Rotators – move one part over another
* rotation of the head
* common movement of the ball and
socket joints
• Constrictors and Dilators or Sphincters
– circular muscles that close and
open circular orifices
Supinator – movement of the palm from a
posterior to an anterior anatomical position
(palm is facing upward)
* the radius and ulna are parallel
Pronator – the palm of the hand is in posterior
position or facing downward
Five Golden Rules of Skeletal
Muscle Activity:

1. All muscles cross at least one joint.

2. Typically, the bulk of the muscle lies proximal to
the joint crossed.

3. All muscles must have at least two attachments:
the origin and insertion.

4. Muscles can only pull, they never push.

5. During contraction, the muscle insertion moves
Oral Reports
Muscular contraction (5 members)
Fatigue (5 members)
Diseases of muscles (5 members)
Kinds of Muscle Contraction:
1. Single twitch – when a muscle is
given a single stimulus
Three phases of contraction:
A.
Latent period – lasting about 0.01 second
- interval between the application of the stimulus and
the beginning of the visible shortening of the muscle
B. Period of contraction – about 0.04 second in duration
- a period during which the muscle shortens and does
work
C. Period of relaxation – lasting about 0.05 second
- period during which the muscle returns to its original
shape
2. Tetanus

The normal contractions of the muscles do
not occur as a single twitch but as a
sustained contractions evoked by a
volley of separate stimuli.

The nerve impulse is called tetanus, and
while it prevails, the stimuli occur as
rapidly that relaxation cannot occur
between successive contractions.
3. Tonus or “tone”

The state of sustained partial contractions
present in all normal skeletal muscle as long as
the nerves to the muscles are intact.

Cardiac and smooth muscles exhibit tonus even
after their nerves are cut.

Skeletal muscles – eliminate tonus immediately
when nerves are cut
Oral Reports (Circulatory
System)
Topics:
1. Cardiac cycle – 5 members
2.
Blood pressure – 5 members
3.
Blood Clotting – 5 members
4.
Cardiovascular diseases – 5 members
The End
Muscles of the Cat
Neck Muscles
1. Digastric
3. Geniohyoid
2. Mylohyoid
4. Sternohyoid
5. Sternomastoid
7. External jugular vein
6. Clavotrapezius
Trunk and Shoulder – Thoracic
(Superficial)
1. Pentoantebrachialis
5. Linea alba
3. Pectoralis minor
2. Pectoralis major
4. Xiphihumeralis
6. Epitrochlearis
10. Serratus
ventralis
11. Latissimus
dorsi
7. Triceps
8. Teres major
9. Subscapularis
Trunk & Shoulder Muscles- Thoracic
(Deep)
1. Rectus thoracis
3a. Scalenus
anterior
b. Scalenus
medius
c. Scalenus
posterior
2. Rectus
abdominis
4. Serratus
ventralis
5. Subscapularis
7. Coracobrachialis
8. Latissimus
dorsi
6. Teres major
Shoulder & Upper Back ( Superficial)
1. Latissiumus dorsi
2. Spinotrapezius
3. Acromiotrapezius
4. Clavotrapezius
5. Levator scapulae
ventralis
7. Acromiodeltoid
8. Clavodeltoid
6. Spinodeltoid
10. Triceps long head
9. Triceps lateral
head
Shoulder & Upper back ( Deep )
1. Clavotrapezius
9. Rhomboideus
capitis
8. Clavodeltoid
10. Splenius
capitis
7. Acromiodeltoid
6. TricepsLateral head
5. Triceps –
long head
2. Acromiotrapezius
3. Supraspinatus
11. Rhomboideus minor
13. Spinotrapezius
4. Infrasspinatus
12. Rhomboideus
major
15. Longissimus
14. Latissimus dorsi
Upper arm - Lateral
1. Acromiotrapezius
2. Levator scapulae ventralis
4. Triceps – lateral head
(reflected
8. Clavodeltoid
3. Teres major
7. Brachialis
5. Triceps – long head
6. Triceps – medial head
9. Aconeus
Upper Arm - Medial
1. Clavodeltoid
2. Biceps brachii
3. Triceps-medial
head
4. Epitrochlearis
5. Triceps-long
head
Forearm – Lateral Aspect
2. Triceps-lateral
head
3. Bracialis
4. Brachioradialis
5. Extensor carpi radialis longus
6. Extensor carpi radialis brevis
1.Triceps-long
head
10. Flexor carpi
ulnaris
11. Anconeus
7. Extensor digitorum
communis
8. Extensor digitorum lateralis
9. Extensor carpi ulnaris
Forearm – Medial Aspect
1. Brachioradialis
3. Extensor carpi radialis brevis
5. Flexor carpi radialis
7. Flexor carpi ulnaris
10. pitrochlearis
12. Medial head of triceps
2. Extensor carpi radialis longus
4. Pronator teres
6. Palmaris longus
8. Clavodeltoid
9. Biceps brachii
11. Long head of triceps
13. Flexor digitorum superficialis
Abdominal Muscles
1. Aponeurosis
2. Rectus abdominis
3. Transverse abdominis
4. External oblique
5. Internal oblique
Lower Back Muscles
1. Multifidus
2. Erector spinae
3. External oblique
4. Latissimus dorsi
5. Spinotrapezius
6. Thoracolumbar
fascia
Upper Leg – Lateral & Superficial Aspects
1. Semitendinosus 4. Gluteus maximus
2. Biceps femoris 5. Gluteus medius
3. Caudofemoris
6. Tensor fascia lata
7. Sartorius
Upper Leg (Lateral & Deep Aspects)
1. Biceps femoris (reflected) 2. Caudo femoralis (reflected)
3. Gluteus maximus (reflected) 4. Gluteus medius 5. Tensor fascia lata
6. Semitendinosus 7. Semimembranosus 8. Adductor femoris 9. Sciatic nerve
10. Vastus lateralis 11. Sartorius 12. Tibialis anterior
13. Extensor digitorum longus 14. Peroneus 15. Soleus 16. Gastrocnemius
17. Slippy’s tail
Upper leg (Medial & Superficial)
1. Sartorius
4. Semitendinosus
6. Plantarius
2. Gracilis
3. Skippy’s tail
5. Gastrocnemius
7. Soleus
Upper Leg (Medial & Deep)
1. Sartorius
4. Vastus medialis
7. Adductor longus
9. Semimembranosus
11. Gastrocnemius
2. Vastus lateralis
3. Rectus femoris
5. Iliopsoas
6. Pectineus
8. Adductor femoris (2 heads)
10. Semitendinosus
Lower Leg (Lateral Aspect)
1. Tibialis anterior
2. Extensor digitorum longus
3. Peroneus longus
4. Peroneus brevis
5. Peroneus tertius
6. Soleus
7. Gastrocnemius
8. Biceps femoris
9. Semitendinosus
10. Semimembranosus
11. Adductor femoris
12. Vastus lateralis
Lower Leg (Medial Aspect)
1. Gastrocnemius
2. Plantaris
3. Soleus
4. Flexor digitorum longus
5. Tibia (bone)
6. Tibialis anterior
7. Calcaneus tendon (Tendon of Achilles)
8. Lucky Kitty’s foot