Muscles
What you Need to Know
•
Look briefly at the Structure of:
1) Skeletal, 2) Smooth & 3) Cardiac Muscle
• Naming, Identification, Functions
You are only responsible for the identification of
ALL muscles which are on your Lab Packet
In general:
Generates force to move your bones
Propel body fluids & ingested food
Generate and distribute heat
Muscle
Specialized for contraction  movement of skeleton
or internal organs
c) smooth
a) skeletal
b) cardiac
Skeletal Muscle
-generally attaches to bone causes
movement of skeleton
Characteristics:
-long & unbranched, tightly packed, parallel cells
-multinucleated
-striated (striped)
-voluntary (conscious control)
Cardiac Muscle
-muscle of the heart
Characteristics:
-1 nucleus per cell
-branched cells with mild striations
-involuntary (not consciously controlled)
Smooth Muscle
-movement within internal organs
other than the heart (e.g. digestive
tract, bladder, arteries, etc.)
Characteristics:
-tapered cells
-single nucleus/cell
-no striations
-involuntary
Observe muscle slides!
Use these pictures to
quiz yourself!
Dense Regular Connective Tissue
-forms tendons (attach muscle to bone)
and ligaments (attach bone to bone)
-fibroblasts in collagen matrix
Collagen
fibers
Fibroblasts
Facial Muscles
Frontalis: raises
eyebrows; wrinkles
forehead
Orbicularis oculi:
closes eye
Buccinator:
compresses cheek
Masseter: elevates
mandible (closes jaw)
p. 84
Temporalis:
elevates
mandible
Orbicularis
oris: closes and
purses lips
Facial Muscles
Temporalis:
elevates
mandible
Frontalis: raises
eyebrows; wrinkles
forehead
Orbicularis oculi:
closes eye
Buccinator:
compresses cheek
Masseter: elevates
mandible (closes jaw)
No equivalent
picture in lab
manual
Orbicularis
oris: closes and
purses lips
Sternocleidomastoid
-If both contracted flexion of head when both (nod down)
-If one contracted rotates head to opposite shoulder
Muscles
Many muscles form antagonistic muscle pairs
Agonist: muscle that’s causing movement
Antagonist: muscle that opposes the agonist
An example…
During arm flexion:
Agonist: Biceps brachii
Antagonist: Triceps brachii
During arm extension:
Agonist: Triceps brachii
Antagonist: Biceps brachii
Muscles that Move Shoulder
Trapezius: elevates (i.e. raises
shoulders) & retracts scapula (i.e.
pulls shoulders back)
Elevates scapula
Retracts scapula
Muscles that Move Shoulder
No pic in lab
manual
Pectoralis minor: draws scapula forward & downward
(i.e. pulls shoulders down and forward)
Draws scapula
forward
Draws scapula
downward
p. 82, 85
Muscles that Move Shoulder
Serratus anterior: draws scapula forward (i.e.
pulls shoulder forward)
Serratus
anterior
Draws scapula
forward
Muscles that Move the Upper Arm
Pectoralis major: flexes (moves arm
up and forward) & adducts upper
arm (moves arm toward the body)
Flexes upper arm
Adducts upper arm
Muscles that Move the Upper Arm
Latissimus dorsi: extends (i.e. moves
arm down to the rear) & adducts arm
(moves arm toward body)
Extends upper arm
Adducts upper arm
Muscles that Move Upper Arm
Deltoid: abducts arm (raises
arm up away from the side)
Abducts
arm
Deltoid
Biceps brachii:
flexes forearm
Brachialis:
flexes
forearm
Biceps
brachii
Brachialis
Moving the Forearm
Biceps
brachii
Brachialis
Flexion of forearm
Muscles that Move the Forearm
p. 83, 85
Triceps brachii:
extends the forearm
extension
Flexors & Extensors of Hand
Hand flexor group: flex the hand
p. 82. 84,
85
Hand extensor group:
extend the hand
p. 83. 85
p. 82
Muscles of Abdominal Wall –
Movement of Spine
Rectus abdominus:
flexes vertebral column
Muscles of Abdominal –Moving the spine
Lateral flexion
External oblique:
compresses
abdomen; rotates
trunk; lateral flexion
Trunk
Rotation
Internal oblique:
compresses abdomen;
trunk rotation; lateral
flexion No pic
Transversus abdominis:
compresses abdomen
No pic
Compressing
abdomen
Muscles of Chest Wall –Movement of Ribs
Internal intercostals:
depresses rib cage
during forced expiration
External intercostals: elevates
rib cage during inspiration
No pics
Diaphragm: prime mover
during inspiration; increases
vertical dimension of thorax
Muscles of Chest Wall –Movement of Ribs
Internal
intercostal
External
intercostal
Muscles that Move the Thigh
Gluteus maximus:
extends thigh
p. 83, 86
Muscles that Move the Thigh
iliopsoas: flexion of thigh
Flexion of thigh
Muscles that Move the Thigh
Flexion of thigh
Abducts of thigh
Tensor fascia latae:
flexes & abducts thigh
Muscles that Move the Thigh
Adducts of thigh
Flexion of thigh
Adductor group:
adducts and flexes
thigh
Muscles that Move the Thigh
Lateral rotation &
flexion of thigh
sartorius:
flexes & laterally
rotates thigh;
helps you sit
cross-legged
Muscles that Move the Thigh
Knee extension
Quadriceps
femoris group:
extends knee
Flexion of thigh
Rectus femoris:
extends knees and
flexes thigh
Muscles that Move the Lower Leg
Extension of thigh
Hamstring group:
extends thigh &
flexes knee
Knee flexion
Muscles that Move the Foot
Tibialis anterior:
dorisflexes foot
Gastrocnemius:
plantar flexes foot,
flexes knee
Soleus: plantar
flexes foot
Today’s Activities
Muscles: Tissue & Histology
Examine the following slides using the microscope:
1) Skeletal muscle
3) Cardiac muscle
4) Dense regular connective tissue
2) Smooth muscle
Muscles: Gross Anatomy
Use the models and diagrams in you textbook & lab manual to
study locations & actions of the muscles listed on pp. 76-79
Diagrams in textbook = right side; most models = left side
Don’t worry about extra muscles described in textbook
Don’t worry about extra actions described in textbook
Answer questions, fill out diagrams on pp. 80-86
If you get done early, you can go back to the bones, etc.
DO NOT leave until you have been excused, or you will be
marked absent!!!
Medial View
Radial view
Medial View-Deep flexors
Lateral View
Lateral View-Deep extensors
Lateral View-Deep shoulder
extensors
Anterior View
Lateral View
Medial View
Posterior View
Plantar
surface
Search “MuscleandMotion” on YouTube