Lab #7: Axial Muscles & Muscle History Flashcards
Muscle is subdivided into 3 types
smooth muscle, cardiac muscle, skeletal muscle
All muscle tissue functions through the interaction of two proteins
actin & myosin
Function of actin & myosin
accomplish the main goal of muscle; to contract and consequently force generation (ex. movement of limbs (skeletal), pumping blood (cardiac), and squeezing hollow organs (smooth)
General function of muscle
Movement Posture Stability Communication Control Thermoregulation
Mary Played Solitare Carefully at the Card Tournament
- Movement of body parts and organ contents, which allow for important forms of communication
(ex. speech, writing, expressions, mannerisms) - Maintaining posture and preventing unwanted movement (ex. stability)
- Controlling openings and passageways/hollow organs
- Thermoregulation (heat production)
which muscle is striated and which is non-striated?
- Skeletal and cardiac muscle = striated
- Smooth muscle = non-striated
Striations in muscle are created by…
the arrangement and overlap of actin and myosin proteins
Cells from muscle tissues are also called…
fibers
Different physical descriptions of the muscles
- skeletal muscle cells are long and fibrous
- smooth muscle fibers are spindle-shaped
- cardiac muscle fibers are shorter than skeletal muscle cells but vary in shape and size
Smooth muscle cells are often found in….
sheets or individual cells that encircle hollow organs
What do smooth muscle cells look like in longitudinal sections?
elongaged and pointed at the ends and fatter in the middle
What do smooth muscle cells look like in cross/transverse sections?
thin and wavy in appearance
What connects each smooth muscle fiber to its neighbor?
gap junctions
Gap junctions allow for….
communication between cells
How are smooth muscle cells normally grouped?
they are normally grouped in thick bands that are orientated in different directions around an organ (such as intenstines or stomach)
Longitudinal cardiac muscle fibers resemble…
the shape and arrangement of smooth muscle cell at low magnification
Key identifying structures of cardiac muscle cells?
intercalated disc, and within those, the adhering junctions and desosomes
Intercalated disc
constitutes border of each cell, communicates between cells using gap junctions
Cross section cardiac muscle cells look similar to….
skeletal muscle, except cardiac muscle sections have thicker connective tissue regions between muscle fiber than skeletal muscle
Where is the nuclei found in cardiac muscle and what does it look like?
It’s found in different locations each time and they appear dark because of a hematocylin stain
Cross section skeletal muscle cells appear as…
groups of circular cells of generally the same size
fascicles
bundles of skeletal circular muscle cells
Perimysium
thicker connective tissue regions that Fascicles are distinguished by
Endoymsium
found in between the fibers
How do skeletal muscle cells differ from other cells?
- enormous in both length and volume
- contain more than one nucleus
Sarcmere
the smallest contractile/functional unit of a skeletal muscle, can only be observed through an electron microscope
Where are blood vessels in skeletal muscle often found?
within the thicker connective tissue regions of the perimysium
What are muscle spindles? What is their significance?
four small muscle fibers grouped togther. they’re important for helping to communicate to the nervous system the position and length of the muscle as a whole
Skeletal muscles comprise ____ of total body mass
30-40%, women leaning towards the 30s and men towards the 40s
Skeltal muscles vary in both shape and size, but can be categorized based on the _______
orientation of a muscle’s fibers relative to its tendon to which they attach
Skeletal muscle functions to _____
shorten the distance between two points of the body
Most common skeletal muscle arrangements
Circular, Convergent/radiate, Parallel/fusiform, Pennate (uni-, bi-, and multi-pennate)
Circular muscle arrangement
Fibers are arranged in concentric rings (ex. sphincters)
Convergent/radiate muscle arrangement
Fibers are arranged in a broad, or flared, pattern from the origin to its insertion as a single tendon (ex. Pectoralis major)
Parallell/fusiform muscle arrangement
Fibers run parallel with the long axis of the muscle (ex. Biceps brachii, sartorius, soleus)
Pennate muscle arrangement
Fibers run at an angle relative to the tendons of that muscle (ex. Unipennate: extensor digitorum longus, Bipennate: rectis femoris, Multipennate: deltoid)
List all muscle arrangements
- Fusiform
- Unipennate
- Circular
- Convergent
- Bipennate
- Parallel
- Multipennate
Facial Muscles
-Galea aponeurotica (epicranial aponeurosis or aponeurosis epicraialis)
→ Frontalis
→ Occipitalis
-Orbicularis oculi
-Nasalis
-Masseter
-Buccinator
-Modiolus
-Orbicularis oris
-Platysma
-SternocleidomastoidGalea aponeurotica and its containing muscles
dense fibrous connective tissue covering top of cranium connecting frontalis and occipitalis muscles
Frontalis
raises eyebrows, wrinkles forehead
Frontalis
raises eyebrows, wrinkles forehead
Occipitalis
pulls scalp posteriorly
Temporalis
closes jaw (elevates and retracts mandible)
Orbicularis oculi
closes eyelids
Nasalis
flares nostrils; compresses nasal cartilage
Masseter
principal muscle for jaw movement; closes jaw
Buccinator
compresses cheeks; aids in food position for chewing
Modiolus
intersection of facial muscles; provides stability for mouth movement and facial expression
Orbicularis oris
closes mouth; puckers lips
Platysma
creates downward sag of mouth; tenses skin of neck
Sternocleidomastoid
flexes and laterally rotates head
Muscles for Chewing and Swallowing
- Suprahyoid group
- Infrahyoid group
Suprahyoid group
forms floor of oral cavity; provides an anchor for tongue; elevates hyoid bone; moves larynx superiorly during swallowing
Infrahyoid group
depresses hyoid bone; depresses larynx during swallowing and speaking
Mucles in the Suprahyoid group
- Digastric (anterior belly, posterior belly)
- stylohyoid
- mylohyoid
Muscles in the Infrahyoid group
- sternohyoid
- thyrohoid
- sternothyroid
- Omohyoid (which has the superior and inferior belly)
Muscles for Breathing
- External intercostals
- Internal intercostals
- Diaphram
External intercostals
elevates ribcage; external = inspiration
Internal intercostals
depresses ribcage; internal = expiration
Diaphram
principle muscle for inspiration, muscle shortening flattens this muscle to increase lung volume
Breathing
the physical process of moving air in and out of the lungs
Respiration
the chemical process or utilization of gases used and created for metabolic systems, such as producing ATP
Chest and Abdominal Muscles
- Pectoralis major
- Pectoralis minor (deep
- Serratus anterior
- Rectus abdominis
- External oblique
- Internal oblique (deep)
- Transverse abdominal (deep)
Pectoralis major
adducts and medially rotates arn
Pectoralis minor (deep):
moves scapula forward and downward
Serratus anterior
rotates scapula laterally and upward
Serratus anterior
rotates scapula laterally and upward
Rectus abdominis
Flexes and rotates lumbar region of vertebral column; stabilizes pelvic region during walking
External oblique
flexes vertebral column when contracting simultaneously; helps to rotate trunk and lateral flexion when contracting individually
Internal oblique (deep)
same as external oblique
Internal oblique (deep)
same as external oblique
Transverse abdominal (deep)
compresses abdominal cavity and ribs; aids in stabilizing thoracic and abdominopelvic regions
Back Muscles
-Trapezius
-Rhomboideus major and minor (deep)
-Latissimus dorsi
-Deltoid
-Rotator cuff
→ Subcapularis
→ Supraspinatus
→ Infraspinatus
→ Teres minor
-Teres major (deep)
-Erector spinae
→ iliocostalis
→ longissimus
→ spinalis
-Semispinalis
-Multifidus
Trapezius
elevates, rotates, and stabilizes scapula; shrugging shoulders
Rhomboideus major and minor (deep)
Stabilizes scapula; works in conjunction with trapezius muscle
Latissimus dorsi
extends and adducts arm; medially rotates arm at shoulder
Deltoid
principal muscle for abduction of arm
Rotator cuff
four deep muscles that collectively stabilize the glenohumeral joint
→ Subcapularis: rotates arm medially
→ Supraspinatus: initiates abduction of arm
→ Infraspinatus: rotates arm laterally
→ Teres minor: rotates arm laterally
Teres major (deep)
extends and adducts arm; rotates arm medially
Teres major (deep)
extends and adducts arm; rotates arm medially
Erector spinae
principal muscle group for extending back, consists of 3 columns
→ iliocostalis
→ longissimus
→ spinalis
Semispinalis
extends and rotates head and vertebral column
Semispinalis
extends and rotates head and vertebral column
Multifidus
stabilizes lowe thoracic and lumbar region of vertebral column
