AN120: Lesson 2 Flashcards
Fascia envelops and supports…
various structures of the body, including:
1. nerves
2. joints
3. muscles
4. tendons
5. ligaments
T/F: fascia is a network of CT as subcutaneous tissue
True, fascia is subcutaneous tissue.
What roles does fascia serve?
- protecting and suporting internal structures of the body
- heavily reduces friction between tissue
- transmits & distributes mechanical stress produced by external force or m.s contraction
What are the 2 types of fascia?
- Superificial
- Deep
What are the components of superficial fascia?
- loose areolar CT
- adipose tissue
What is the main component of superficial fascia?
Loose areolar tissue with spaces being made of fatty tissue and tissue fluid.
What does the superficial fascia contain?
the cutaneous/superficial branches of the skin’s…
- nerves
- veins
- arteries
- lymphatics
where is superficial fascia the thickest and why?
thickest in:
- scalp
- back of neck
- palms of hands
- soles of feet
because they have numerous bundles of collagen fibres that hold firmly to the deeper structures
where is superficial fascia thinnest & why?
- eyelids
- auricle of the ear
- penis
- scrotum
- clitoris
thinnest because they are devoid of adipose (fat) tissue
what is deep fascia?
a membraneous layer of CT
- invests muscles and other deep structures.
regions deep fascia is found in:
- Neck
- Limbs
- Abdomen & Thorax
- Joints
in the neck, deep fascia is…
- well-defined layers that may play an important role in determining path of infection.
how does deep fascia help in infection?
knowledge of the arrangement of deep fascia can explain path taken by infection when it spreads from its primary site.
an example of deep fascia & infection is…
in the neck
fascial planes explain how infection can extend from: floor of mouth to: laynx
in limbs deep fascia…
- definite sheath around muscle & other structures
- holds muscle and other structures in place
- fibrous septa extend from deep surface of membrane to divide interior of limbs into compartments
in abdomen & thorax, deep fascia is…
- thin film
- areolar tissue
- covers muscles & aponeuroses
serous describes…
a watery-like fluid
in region of joints, deep fascia is…
- thickened bands
- called retinacula
- holds underlying tendons in place (position)
- prevents friction
the serous cavity’s layers are…
a serous cavity lined by a serous membrane
why is it considered a cavity?
it is a hollow sac of air whose membrane is made of serous fluid.
what is the function of the serous cavity?
- allows for organs to invaginate it and move around.
- lubricate
- reduce friction between organs during motion
the serous cavity of the lungs:
pleural cavity
the serous cavity of the heart:
pericardium
the serous cavity of the intestines:
peritoneum
the peritoneum allows intestines to…
move freely during digestive processes
the parts of the serous membrane are:
inner and outer membranes
where is the inner membrane?
associated with the surface of the visceral organ
where is the outer membrane of the serous cavity?
outer wall of cavity
what are the 3 types of ms?
- skeletal
- smooth
- cardiac
define skeletal ms
- voluntary muscle
- produce movement of the skeleton
- made up of stiped m.s. fibres
what is the origin?
attachement that moves the least
what is the insertion?
attachment that moves the most
what is the fleshy part of the muscle called?
belly
how many attachments can skeletal muscle have?
2 or more
what are muscle attached to and by what?
attached to:
- ligaments
- bones
- cartilage
by:
- tendons
- aponeurosis
- raphe
what are tendons?
cords of fibrous tissue that attach muscle to other structures.
- found in the ends of all muscles
define aponeurosis:
a thin but strong sheet of fibrous tissue that attaches to certain flat muscles
define raphe
an interdigitation of the tendinous ends of fibres of flat muscle.
what is the internal structure of muscle?
- muscle fibre
- endomysium
- fascicles
- perimysium
- muscle (bundle of fasciculi)
- epimysium
endo to peri to epi
define endomysium
connective tissue that encloses the muscle fibres
which is stronger; the endo or perimysium?
the perimysium is stronger
define perimysium
a sheath of CT that encloses individual fasciculi.
what are muscle fibres bounded by?
they are bound together with areolar tissue.
what happens to the areolar tissue between muscle fibres?
they condense on the surface to form a fibrous envelope called the epimysium.
how can individual muscle fibres be arranged?
parallel or obliquely to the long axis of the muscle.
what happens to muscle when it contracts?
it shortens by a third to one half (1/3 to 1/2) of its resting length
muscle whose fibres are parallel to the line of pull will…
bring about a greater degree of movement (wider range of motion)
examples of parallel fibre arrangements:
- sternocleidomastoid
- rectus abdominus
The range of motion is determined by…
direction muscle fibres run relative to the long axis of muscle/ line of pull.
which type of muscle has fibres that run obliquely to the line of pull?
pennate muscle
so the line of pull is…
the long axis of the muscle
what do pennate muscles resemble?
they resemble a feather
types of pennate muscles are:
- unipennate
- bipennate
- multipennate
what are unipennate muscles?
with example
- muscle where tendons lies along one side of the muscle
- muscle fibres pass obliquely to tendon
- ex: extensor digitorum longus
what is bipennate muscle?
w ex
- tendon lies in centre of muscle with muscle fibres passing BOTH sides
- ex. rectus femoris
what is multipennate muscle?
w ex.
has two forms:
1. where muscle is arranged as a series of bipennate muscles lying alongside each other [ex: acromial fibres of deltoid]
2. can be a tendon lying within the centre, with muscle fibres passing from all sides and converging as they go [ex: tibialis anterior]
for a volume of muscle substance, pennate muscle…
have many more fibres compared to parallel fibre-arranged muscle and therefore more powerful.
pennate muscle have a larger… causing…
larger cross section, causing for a larger force.
examples of parallel muscles:
- sternocleidomastoid
- rectus abdominis
examples of oblique/ pennate muscle:
- extensor digitorum longus
- rectus femoris
- deltoid (acromial fibres)
- tibialis anterior
what are fusiform muscle?
w ex.
- spindle-shaped muscle
- has a thick round belly (or bellies)
- tapered ends
ex: bicep brachii
define convergent muscle:
w example
- arise from a broad area but converge to form a single tendon
ex: pectoralis major
define circular muscle:
w example
- surround a body opening/ orifice
- when contract they constrict
ex. obicularis oculi (closes the eyelid)
the external oblique muscle is an example of:
flat parallel muscle with aponeurosis
naming of skeletal muscle is according to…
- position
- action
- attachment
- shape
- size
- number of heads/ bellies
- depth
shape of muscle naming is divided into:
- deltoid [triangular]
- rectus [straight]
- teres [round]
- quaderatus [square]
naming based on size of muscle:
- major [large]
- minor [small]
- latissimus [broadest]
- longissimus [longest]
naming of ms based on number of heads/ bellies:
- biceps [2 heads]
- triceps [3 heads]
- quadriceps [4 heads]
- digastric [2 bellies]
naming based position of m.s.
- pectoralis [of chest]
- supraspinatus [above spine of scapula]
- brachii [of the arm]
naming based on attachment of muscle:
- sternocleidomastoid [from sternum to clavicle to mastoid process]
- coracobrachialis [from coracoid process to arm]
naming of ms via depth:
- profundus [deep]
- superficialis [superficial]
- externus [external]
naming of ms via action
- extensor [extend]
- flexor [flex]
- adductor pollicis [adduct]
classification of skeletal muscle according to action:
- prime mover
- antagonist
- fixator
- synergist
define prime mover
- chief muscle/ member of chief muscle group
- responsible for a particular movement
quadricep femoris is the prime mover in…
knee joint extension
the primary mover in knee joint extension is…
quadricep femoris
define antagonist
- muscle that opposes the action of the prime mover
what opposes the quadricep femoris during knee extension?
bicep femoris is the antagonist during knee extension
what is a prerequisite for prime mover contraction?
the antagonist muscle MUST be equally relaxed.
define fixator
- contracts isometrically so it…
- stabilizes the origin of prime mover so that it can act efficiently
example of fixator action:
muscles of shoulder girdle that attack to the trunk contract as fixators to allow deltoid to act on shoulder joint.
define synergist and their function
prevents unwanted movements in intermediate joints that the prime mover muscle may pass through to reach target joint for action.
the mechanism of synergists:
a group of muscles (synergists) will contract and stabilize intermediate joints
example of synergist action:
the flexor & extensor muscle of carpus contracting to fix the wrist joint to allow long flexor & extensor muscle of fingers to work efficiently.
when are the terms for skeletal muscle classification based on action used?
during particular movement; muscles can act as any of them; it all depends on the movement that is to be accomplished.
define muscle tone
- continuous & passive partial contraction
- resistance to passive stretch of resting state
function of muscle tone:
helps maintain posture & declines during REM sleep.
what is muscle tone regulated by?
the activity of motor neurons
what can muscle tone be affected by?
- age
- nerve damage
- disease
what is important in clinical examination and why?
tone of muscle because if flaccid, then either the afferent or efferent (or both) beurons have been interrupted, and they are both involved in the reflex arc.
what is needed to produce muscle tone?
reflex arc
why is knowledge of muscle attachment so important?
- to understand normal/ abnormal actions of individual muscles or muscle groups
without this knowledge, you cannot analyze the abnormal gait of a patient.
what is smooth muscle?
- long, spindle-shaped fibres
- fibres are closely arranged in bundles/ sheets
- provides propelling power in tubes of the body through lumen.
what does the smooth muscle do in digestive system?
causes ingested food to be thoroughly mixed with digestive juices
how does smooth muscle help in digestive system?
a wave of contraction of the circularly-arranged fibres that pass along the tube, milking contents onward
which fibres pull the wall of the tube proximally over the contents? (name of action)
longitudinal fibres, they complete peristalsis
where are fibres irregularly arranged & interlaced & why?
in storage organs: in the uterus & urinary bladder
- makes contraction slow and sustained to bring about expulsion of contents of the organ
how are blood vessel fibres arranged and why?
- circularly
- to modify caliber of lumen
what are ways smooth muscle can contract?
via:
1. local stretching of fibres
2. nerve impulses from autonomic nerves
3. hormonal stimulation
cardia muscle forms the…
myocardium of heart
cardiac muscle fibres are:
striated fibres that branches & unite with each other
- arranged in spirals
cardiac muscle contraction is…
spontaneous & rhythmic
what do special cardiac muscle fibres do?
conducting system of the heart
what supplies the cardiac muscle and where?
the autonomic nerve fibres that terminate in nodes of the conducting system & in the myocardium
how does necrosis of cardiac muscle occur?
when one of the large coronary arteries (arteries that supply blood to the heart) gets suddenly blocked, often leading to the patient’s death.
