Exam 3 Flashcards
<p>Deltoid origin</p>
<p>acromial end of clavicle, the acromion, and the spine of the scapula</p>
<p>Deltoid insertion</p>
<p>deltoid tuberosity on lateral midregion of humerus</p>
<p>Deltoid action</p>
<p>anterior fibers flex and medially rotate arm; middle fibers prime mover of
arm abduction; posterior fibers extend and laterally rotate arm.
</p>
<p>Coracobrachialis action</p>
<p>works as a synergist to the pectoralis major in flexing and adducting the arm
(a) Action = adducts and flexes arm</p>
<p>Teres major</p>
<p>Latin for “round” and “greater”) works synergistically with the latissimus dorsi by extending, adducting, and medially rotating the arm.
(a) Action = same as latissimus dors</p>
<p>4 rotator cuff muscles</p>
<p>Subscapularis Supraspinatus Infraspinatus Teres minor </p>
<p>Subscapularis</p>
<p>located on the anterior surface of the scapula (between scapula
and ribs).
- Action = medially rotates arm, like when you wind up to pitch a baseball</p>
<p>Supraspinatus</p>
<p>located superior to the scapular spine.
- Action = abducts the arm as when you start to execute a pitch of a baseball, with your arm fully abducte</p>
<p>Infraspinatus</p>
<p>is located inferior to scapular spine.
- Action = adducts and laterally rotates the arm, like when you slow down your
arm after pitching a basebal</p>
<p>Teres minor</p>
<p>Latin for “round” and “lesser”) is located inferior to the infraspinatus.
- Action = same as infraspinatus (synergistic muscles)</p>
<p>2 compartments that move the elbow and forearm</p>
<p>Anterior (flexor) compartment, which contains primarily elbow flexors
- Posterior (extensor) compartment, which contains elbow extensors</p>
<p>Main flexors</p>
<p>Biceps brachii</p>
<p>Main extensor </p>
<p>Triceps brachii</p>
<p>Biceps brachii</p>
<p>Latin for “two heads” and “arm”) is a large, two-headed
muscle on the anterior surface of the humerus.</p>
<p>Biceps brachii origin </p>
<p>long head originates on the supraglenoid tubercle of scapula while the short
head originates on coracoid process of scapula</p>
<p>Biceps brachii insertion</p>
<p>radial tuberostiy and bicipital aponeurosis (</p>
<p>Biceps brachii action</p>
<p>flexes elbow joint and is powerful supinator of forearm. An example of this
supination movement occurs when you tighten a screw with your right hand. [The tendon of the long head of the biceps brachii crosses the shoulder joint, so this muscle helps flex the humerus as well, albeit weakly]</p>
<p>Triceps brachii</p>
<p>Latin for “three heads” and “arm”) is the large, three- headed muscle on the posterior surface of the arm. It is the prime extensor of the elbow joint, and so its action is antagonistic to that of the biceps brachii</p>
<p>Triceps brachii origin</p>
<p>long head originates at infraglenoid tubercle of scapula, the lateral head
originates on posterior humerus above radial groove, and the medial head originates
on posterior humerus below radial groove</p>
<p>Triceps brachii insertion</p>
<p>all three parts of this muscle merge to form a common insertion on the
olecranon of the ulna</p>
<p>Triceps brachii action</p>
<p>primary extensor of the elbow joint [only the long head of the triceps
brachii crosses the glenohumeral joint, where it helps extend the humerus]</p>
<p>Anterior compartment of the forearm</p>
<p>Most of the anterior compartment muscles originate on the medial epicondyle of
the humerus via a common flexor tendon. Muscles in the anterior compartment of the forearm tend to flex the wrist, the metacarpal joints, and/or the interphalangeal joints of the fingers.</p>
<p>Posterior muscles of the forearm</p>
<p>Most of the posterior compartment muscles originate on the lateral epicondyle of the humerus via a common extensor tendon. Muscles in the posterior compartment tend to extend the wrist, the metacarpal joints, and/or the interphalangeal joints.</p>
<p>What are the tendons surrounded by</p>
<p>The tendons of forearm muscles typically are surrounded by tendon (synovial)
sheaths and held adjacent to the skeletal elements by strong fascial structures.</p>
<p>Fibrous bands in the wrist</p>
<p>Retinacula</p>
<p>Retinacula</p>
<p>The retinacula help hold the tendons close to the bone and prevent the tendons from
“bowstringing” outward.</p>
<p>Flexor retinaculum</p>
<p>Flexor tendons of the digits and the “median nerve” pass through the tight space
between the bones and the flexor retinacula, which is called the “carpal tunnel”.</p>
<p>What are the posterior carpal bones covered in</p>
<p>Extensor retinaculum</p>
<p>Intrinsic muscles of the hand</p>
<p>The intrinsic muscles of the hand are small muscles that both originate and insert on the hand; they are housed entirely within the palm.
1) As was stated earlier, there are no muscles in the fingers (digits).</p>
<p>Anterior compartment of leg</p>
<p>extend the knee or flex the thigh</p>
<p>Lateral,compartment of leg</p>
<p>abducts the thigh</p>
<p>Posterior compartment of leg</p>
<p>flexors of the knee and extensors of the thigh.</p>
<p>Medial compartment of thigh</p>
<p>adductors of the thigh</p>
<p>Where do the majority of the thigh muscles originate from</p>
<p>Os coxae</p>
<p>Sartorius</p>
<p>Latin for “tailor” crosses over the
anterior thigh. It is the longest muscle in the body and it enables one to assume a cross-legged sitting position (hence the designation as the ‘tailor’s muscle”</p>
<p>Sartorius origin</p>
<p>anterior superior iliac spine</p>
<p>Sartorius insertion</p>
<p>tibial tuberosity, medial side</p>
<p>Sartorius action</p>
<p>flexes thigh and rotates thigh laterally; flexes leg and rotates leg medially</p>
<p>Gracilis action</p>
<p>adducts and flexes thigh; flexes leg</p>
<p>Tensor fasciae latae</p>
<p>t attaches to a lateral thickening of the fascia lata, called the “iliotibial tract” (iliotibial band, IT band), which extends from the iliac crest to the lateral condyle of the tibia</p>
<p>Tensor fasciae latae origin</p>
<p>iliac crest and lateral surface of anterior superior iliac spine</p>
<p>Tensor fasciae latae insertion</p>
<p>iliotibial tract (iliotibial band, IT band)</p>
<p>Tensor fasciae latae action</p>
<p>abducts the thigh; medially rotates thigh</p>
<p>Deltoid</p>
<p>The “deltoid” (Greek for “shaped like the letter delta, Δ”) is a thick, powerful
muscle that functions as the prime abductor of the arm and forms the rounded contour of the shoulder. It is also a good location for administering intramuscular (I.M.) injections.</p>
<p>Gluteus Maximus</p>
<p> (Latin for “buttock” and “largest”) is the largest and
heaviest of the three gluteal muscles. It is the chief extensor of the thigh. It is also a common site for intramuscular (I.M.) injections.</p>
<p>Gluteus Maximus origin</p>
<p>iliac crest, sacrum, and coccyx</p>
<p>Gluteus Maximus insertion</p>
<p>iliotibial tract (iliotibial tract, IT band) of fascia lata, linea aspera of
femur, and gluteal tuberosity of femur.</p>
<p>Gluteus Maximus action</p>
<p>extends and rotates thigh laterally</p>
<p>Piriformis</p>
<p>can cause pressure
on a major nerve that runs down the back of the thigh. In some persons the sciatic nerve even passes through the belly of the piriformis muscle</p>
Biceps femoris
Latin for ‘two heads” and” femur”) is a two-headed muscle that inserts on the lateral side of the leg. Its tendon of insertion is easily seen and palpated at the lateral margin of the popliteal fossa when the knee is flexed.
Biceps femoris origin
long head on ischial tuberosity (the part of the pelvis you sit on) while the
short head originates on linea aspera of femur
Biceps femoris insertion
head of fibula
Biceps femoris action
extends thigh (long head only), flexes leg (both long and short heads), and
laterally rotates leg
Semimembranosus
Latin for “half membrane”) is deep to the
semitendinosus and inserts on the medial side of the leg. Its tendon of insertion, along with that of the more superficial semitendinosus, is easily seen and palpated at the medial margin of the popliteal fossa when the knee is flexed
Semibranosus origin
ischial tuberosity
Semimembranosus insertion
posterior surface of medial condyle of tibia
Semimembranosus action
extends thigh and flexes leg; medially rotates leg
Coxal (hip) joint
Acetabulofemoral joint
Actions of the hip joint
(a) Flexion
(b) Extension
(c) Abduction/Adduction (d) Rotation
(e) Circumduction
Fibrocartilage that runs along the rim of the acetabulum
Acetabular labrum
What is the vocal joint secured by
1) A strong fibrous joint (articular) capsule 2) Several ligaments
3) A number of powerful muscles
Ligamentum teres
This ligament does not provide much strength to the joint but it does typically
contain a small artery that supplies some of the blood to the head of the femur
Knee joint
The knee joint is the largest and most complex diarthosis of the body. It is also one of the more commonly injured joints in the body.
1) It is primarily a hinge joint, but when the knee is flexed, it is also capable of slight
rotation and lateral gliding movements
Two articulations of the knee joint
1) The “tibiofemoral joint” is between the condyles of the femur and the condyles of the tibia.
2) The “patellofemoral joint” is between the patella and the patellar surface of the anterior distal femur.
Articular capsule of knee joint
The knee joint has an articular capsule that encloses on the medial, lateral, and posterior regions of the knee joint.
1) The joint capsule does not cover the anterior surface of the knee joint; rather, the
quadriceps femoris muscle tendon passes over the anterior surface.
2) The patella, which we learned earlier is a sesamoid bone, is embedded within this
tendon, and the “patellar ligament” extends inferiorly to the patella and attaches
on the anterior surface of the tibia (at tibial tuberosity).
3) Thus, there is no single unified capsule in the knee, nor is there a common
synovial cavity.
Lcl
The “lateral (fibular) collateral ligament” (LCL) reinforces the lateral surface of the
knee joint.
- This ligament runs from the femur to the fibula and prevents the lower leg from
moving too far medially relative to the thigh.
- Your authors refer to the lateral collateral ligament as preventing
“hyperadduction” of the lower leg relative to the thigh.
- An alternate term to hyperadduction of the lower leg is “varus deviation”, which
means the part distal to the joint is abnormally angulated towards the midline of
the body.
MCL
The “medial (tibial) collateral ligament” (MCL) reinforces the medial surface of the
knee joint.
- This ligament runs from the femur to the tibia and prevents the lower leg from
moving to far laterally relative to the thigh.
- Your authors refer to the medial collateral ligament as preventing
“hyperabduction” of the lower leg relative to the thigh.
- An alternative term to hyperabduction of the lower leg is “valgus deviation”,
which means the part distal to the joint is abnormally angulated away from the
midline of the body.
- The medial collateral ligament is attached to the medial meniscus (see discussion
below) of the knee joint as well, so an injury to the medial collateral ligament
usually affects the medial meniscus
C-shaped Fibrocartilage pads
2) Deep to the articular capsule and within the joint itself is a pair of C-shaped
fibrocartilage pads located on the condyles of the tibia which are called the “medial meniscus” and the “lateral meniscus”.
(a) These fibrocartilage pads help stabilize the joint medially and laterally and act as
cushions between the articular surfaces.
Cruciate ligaments
(a) These ligaments cross each other in the form of an “X”, hence the name cruciate.
(b) The “anterior cruciate ligament” (ACL) runs from the posterior femur to the anterior side of the tibia.
- When the knee is extended, the ACL is pulled tight (taut) and prevents hyperextension.
- The ACL prevents the tibia from moving too far anteriorly of the femur.
(c) The “posterior cruciate ligament” (PCL) runs from the anterioinferior femur to the
posterior side of the tibia.
- The PCL becomes taut on flexion, and so it prevents hyperflexion of the knee
joint.
- The PCL also prevents the tibia from moving too far posteriorly of the femur.
Locking the knee
1) Humans are bipedal animals, meaning that they walk on two feet.
2) An important aspect of bipedal locomotion is the ability to “lock” the knees in the
extended position and stand erect without tiring the leg muscles.
3) At full extension, the tibia rotates laterally so as to tighten the ACL and squeeze
the meniscus between the tibia and femur.
Talocrural joint
highly modified hinge joint that permits dorsiflexion and plantar flexion, and includes two articulations within one joint capsule.
1) One of these articulations is between the distal end of the tibia and the talus.
2) The other articulation is between the distal end of the fibula and the lateral
articular facets of the talus
Deltoid ligament
On the medial side, the strong “deltoid ligament” extends from the medial malleolus of the tibia to the talus, calcaneus, and another tarsal bone.
(a) This ligament prevents overeversion of the foot
3 lateral ligaments
Anterior talofibular ligament
Posterior talofibular ligament
Calcaneofibular ligament
Anthroscope
Disease of the joints can be diagnosed with a specialized flexible endoscope,
Muscle fibers characteristics
a. Excitability, which means it responds to electrical stimuli.
b. Contractility, which means it contracts to move bones or propel materials inside the
body.
c. Elasticity, which means the muscle cell will recoil to its resting length when the
applied tension is removed.
d. Extensibility, which means a muscle cell is capable of extending in length in response
to the contraction of opposing muscle cells (i.e.- the triceps brachii muscle on the back of your arm extends when the biceps brachii muscle on the front of your arm contracts).
Hypertrophy
Increase in muscle fiber size
What type of ,uncles are skeletal muscles
Voluntary muscles
bundles of muscle fibers
fascicles
circular muscles
fibers concentrically arranged around an opening or recess, also called a sphincter
parallel muscles
fascicles that run parallel to its long axis
have a “belly”
convergent muscles
widespread muscle fibers the converge on a common attachment site example is the pectoralis major
pennate
feather muscles, one or more tendons extending through their body and the fascicles are arranged at an oblique angle to the tendon
unipennate muscle
muscle fibers are on the same side
bipennate muscles
muscle fibers are on both sides, these are the most common
multipennate
tendon branches within the muscle example is the deltoid muscle
lever
elongated, rigid object that rotates around a fixed point called the fulcrum
long bone
acts as a lever that moves the resistance
a joint serves as
the fulcrum
a muscle serves as
the effort
the effort is not where the body of the muscle is located but rather…
where the muscle attaches to the bone
first class lever system
EFR
seesaw
ex. atlanto-occipital joint of the neck, muscles in the post side pull inferioirly on the nuchal lines of the occipital bone and oppose the head to tip
ex. triceps brachi
second class levers
FRE
lifting the handles of a wheelbarrow
ex. contracting the calf muscle to elevate the body onto the ball of the foot
third class levers
REF
drawbridge
most common type
ex. flexion of the elbow and elevation of the mandible to bite off a piece of food
3 muscle types
agonist
antagonist
synergist
agonist
prime mover, muscle that contracts to produce a particular movement
ex. triceps brachii
antagonist
muscle whose actions oppose those of the agonist
ex. biceps brachii causing flexion of the forearm
synergist
muscle that assists the prime mover (agonist) in performing its action
ex. teres major assisting the lattissimus dorsi in moving the arm
fibrosis
elasticity of muscle decreases as persons age, usually due to increasing amounts of dense regular connective tissue
What separates the two bellies of the occipitofrontalis
galea aponeurotica
action of the frontal belly of occipitofrontalis
moves the scalp, wrinkles forehead, elevates eyebrows
occipital belly of occipitofrontalis action
moves the scalp slightly posteriorly
orbicularis oris action
closes lips, puckers up the lips
platysma action
pulls lower lip inferiorly, tenses skin of neck, contributes to depression of the mandible
buccinator action
compresses cheek, holds food between teeth while chewing, aids in sucking and blowing
tmeporalis origin
superior and inferior portions of the temporal bone
temporalis insertion
coronoid process of mandible
temporalis action
elevates and retracts mandible
masseter origin
zygomatic arch
masseter insertion
lateral surface of coronoid process, lateral surface and angle of mandible
masseter action
elevates and protracts mandible, prime mover of jaw closure
medial and lateral pterygoid
located near TMJ, help to maximize the efficiency of the teeth while chewing or grinding foods
medial and lateral pterygoid action
elevate and protract the mandible and move it from side to side during chewing
anaerobic bacteria
cannot grow in the presence of oxygen, found in soil or feces and can produce deadly toxins that can alter the function of human muscles (excessive contraction or paralysis)
example of anaerobic bacteria
tetanus, follows a dirty puncture wound, results involuntary contraction, lockjaw
sternocleidomastoid origin
manubrium and sternal ends of clavicles
sternocleidomastoid insertion
mastoid processes of temporal bones
sternoclidomastoid action
when both contract, the head is pulled forward and down, when one contracts, it turns the head in the opposite direction of the contracting muscle
splenius capitus action
both contract, head is pulled back and extends and hyperextends the cervical vertebra
when one contracts, turns the head sideways in the same direction as the contracting muscle
semispinalis capitus action
same as splenius capitus
Why are the muscles of the vertebral column stronger than the flexor muscles of the abdominal wall?
they keep us upright against the forces of gravity
2 groupings of muscles associated with the vertebral column
erector spinae
transversospinalis
erector spinae
maintain posture, help us stand erect, along entire vertebral column
when muscles contract together the extend vertebral column
if muscles contract on one side the column flexes laterally toward that same side
inhalation
muscles contract to increase the dimensions of the thoracic cavity creating negative pressure (partial vacuum) to pull air into lungs
exhalation
respiratory muscles relax allowing the elastic recoil of the lung tissues to pull the chest wall inwards and diaphragm upwards, decreasing the dimensions of the thoracic cavity, creating positive pressure to force air out of the lungs
external intercostals
used for restful breathing and extend inferomedially from superior rib to adjacent inferior rib
external intercostals action
elevates ribs by causing them to move up and out (bucket handle) during inhalation to increse the dimensino of the thoracic cavity due to elastic recoil of lung tissue the ribs return passively to their positions
internal intercostals
used during forceful exhalation, located at right angles to the more superficial external intercostals
internal intercostals action
depresses the ribs during forced exhalation
diaphragm
most important muscle with breathing
diaphragm origin
inferior internal surface of lower ribs, xiphoid process of sternum, costal cartilages of inferior ribs, and lumbar vertebrae
diaphragm insertion
central tendon
diaphragm action
contraction during inhalation causes flattening of the diaphragm, expands thoracic cavity, compresses the abdominopelvic cavity
four pairs of muscles in abdomen wall
compress and hold organs in place, assist in defecation, aid in forceful exhalation
what three muscle pairs form the rectus sheath
external and internal obliques, transverse abdominis
six pack is formed by what
rectus abdominis
external oblique action
both contract, compress the abdomen and flex vertebral column, one contracts, causes lateral flexion of the vertebral column
internal oblique action
compress abdomen and flex vertebral column
transverse abdominis
compress the abdomen
rectus abdominis
strap like muscle
rectus abdominis origin
superior surface of pubis near symphysis
rectus abdominis insertion
xiphoid process of sternum and inferior surfaces of middle ribs
rectus abdominis action
flexes vertebral column and compresses the abdominal wall
pelvic diaphragm
3 layers of muscles and associated fasciae
extends from ischium and pubis of the ossa coxae
bony landmarks of the perineum
(diamond shaped)
- ant. pubic symphysis
- coccyx post.
- both ischial tuberosities
urogenital triangle
contains the external genitalia and urethra
anal triangle
contains the anus
levator ani
supports the pelvic viscera, functions as a sphincter at the annorectal juntion, urethra, and vagina
pubococcygeus
help control urinary incontinence and to compress the vagina to aid in sexual enjoyment
pectoralis minor action
protracts and depresses the scapula (shoulders are hunched forward)
serratus anterior action
prime mover in scapular protraction
rhomboid major and minor antagonist
serratus ant. and pectoralis min
rhomboid major action
retracts (adducts) and elevates scapula and inferiorly rotates scapula
rhomboid minor action
same as rhomboid major
trapezius origin
occipital bone, ligamentum nuchae, spinous processes C7-T12
trapezius insertion
clavicle, acromion process, spine of scapula
trapezius action
elevates and retracts (adducts) the scapula, draws head back
latissimus dorsi
prime arm extensor
latissimus dorsi origin
sppinous processes T7-T12, lower ribs, iliac crest, thoracolumbar fascia
latissimus dorsi insertion
intertubercular groove of proximal humerus
latissimus dorsi action
arm extensor, draws the arm downward and backward while it rotates medially
pectoralis major origin
medial clavicle, costal cartilages of upper ribs, body of sternum
pectoralis major insertion
lateral part of intertubercular groove of proximal humerus
pectoralis major action
prime mover of arm flexion, adducts and medially rotates arm
deltoid origin
acromial end of clavicle, the acromion, spine of scapula
deltoid insertion
deltoid tuberosity on lateral midregion of humerus
deltoid action
prime abductor of arm, ant fibers flex and medially rotate arm, middle fibers arm abduction, post fibers extend and laterally rotate arm
coracobrachialis action
synergist to the pectoralis major in flexing and adducting the arm
teres major action
synergistically with latissimus dorsi extending, adducting and medially rotating the arm
rectus femoris origin
ant. inf. iliac spine
rectus femoris insertion
quadriceps tendon-> patella-> patellar ligament-> tibial tuberosity
rectus fermoris action
extends leg, flexes thigh
vastus lateralis origin
greater trochanter and linea aspera of femur
vastus lateralis insertion
quadriceps tendon-> patella-> patellar ligament-> tibial tuberosity
vastus lateralis action
extends leg
vastus medialis origin
intertrochanteric line and linea aspera of femur
vastus medialis insertion
quadriceps tendon-> patella-> patellar ligament-> tibial tuberosity
vastus medialis action
extends leg
vastus intermedius origin
anteriolateral surface of femur
vastus intermedius insertion
quadriceps tendon-> patella-> patellar ligament-> tibial tuberosity
vastus intermedius action
extends the leg
biceps femoris origin
long head on ischial tuberosity while the short head originates on linea aspera of femur
biceps femoris insertion
post. surface of medial condyle of tibia
biceps femoris action
extends thigh and flexes leg, medially rotates leg
semitendinosus origin
ischial tuberosity
semitendinosus insertion
proximal medial surface of tibia
semitendinosus action
extends thigh and flexes leg, medially rotates leg
crural muscles
muscles that move the ankle, foot and toes (some help flex the leg)
tibalis anterior action
dorsiflexes foot and inverts foot
peroneus longus action
everts foot and is a weak plantar flexor
gastrocnemius origin
sup. post. non-articular surfaces of lateral and medial condyles of femur
gastrocnemius insertion
calcaneus via the calcaneal tendon
gastrocnemius action
flexes leg and plantar flexes foot
gastrocnemius
2 thick bellies, spans both knee and ankle joints
soleus action
plantar flexes the foot
plantar aponeurosis
formed from the deep fascia of the foot
extends between the phalanges of the toes and the calcaneus
also encloses the plantar muscles of the foot
structural organization
central and peripheral nervous systems
central nervous system
CNS, brain and spinal cord, protected by the skull and the vertebral canal
peripheral nervous system
PNS, cranial nerves, spinal nerves, ganglia
functional divisions of nervous system
sensory
motor
sensory division
receives sensory info
divided in to 2 components
afferent
inflowing, or towards the center of activity
somatic sensory
somatic senses, such as, touch, pain, pressure, vibration, etc. considered voluntary we have control over them
visceral sensory
transmit nerve impulses from blood vessels and viscera to the CNS, temperature and stretch, involuntary because we are not conscious (sometimes we are aware such as bloating of stomach after eating too much)
motor division
transmits motor impulses from CNS to muscles or glands, efferent, contains both CNS and PNS, 2 components somatic and autonomic
efferent
conductive outward, away from the center of activity, nerve impulses are transmitted from CNS
somatic motor
conducts nerve impulses from the CNS to the skeletal muscles, causing them to contract, voluntary control
autonomic motor
innervates internal organs and regulates smooth muscle, cardiac muscle and glands, typically not under conscious control
cell types from nervous tissue
neurons
glial cells
neurons
excitable cells that initiate and transmit nerve impulses
glial celss
nonexcitable cells that support and protect the neurons
neurons
high metabolic rate, continuous supply of oxygen and nutrients
longevity, survive from womb to old age
after fetal development mitosis is lost
cell body of neuron
serves as the neurons control center and is responsible fro receiving, integrating, and sending nerve impulses (contains nucleus and nerve impulses)
dendrites
branch off the cell body and conduct nerve impulses towards the cell body
axon
transmits nerve impulses away from the cell body, all neurons have one axon
sensory neurons
afferent, transmit nerve impulses from sensory receptors to the CNS, cell bodies are located outside the CNS and housed in the ganglia
motor neurons
efferent, transmit nerve impulses from the CNS to muscles or glands, lie in the spinal cord
interneurons
association neurons, lie entirely in CNS and facilitate communication between sensory and motor neurons, 99% of neurons are interneurons
glial cells
neuroglia, in CNS and PNS, small, capable of mitosis, half the volume of the nervous system
4 types of glial cells
astrocytes, ependymal, microglial, oligodendrocytes
astrocytes
starlike shape due to cytoplasmic projections, wrap around capillaries, protects the delicate brain from toxins, but allows for nutrients to pass, sometimes prevents certain medicine from passing
ependymal cells
line internal cavities (ventricles) of brain and canal of spinal cord, form choroid plexus
what do choroid plexus produce
cerebrospinal fluid
microglial cells
wandering phagocytic cells and remove cellular debris throughout the CNS
oligodendrocytes
large cells with slender cytoplasmic processes that ensheathe portions of axons by repeatedly wrapping around an axon, produces myelin sheath
types of glial cells
satellite and schwann cells
satellite cells
flattened cells arranged around neuronal cell bodies in ganglia and help regulate the movement of nutrients and waste products between neurons and their environment
schwann cells
neurolemmocytes, responsible for myelinating PNS axons
sensory nerves
convey sensory information to the central nervous system and all the axons are conducting impulses in the same direction
motor nerves
convey motor impulses from the central nervous system to the muscles and glands and all the axons are conducting impulses in the same direction
mixed nerves
carry both types of info and some axons are transmitting impulses in one direction, while other axons are transmitting impulses in the opposite direction
when does nervous tissure development begin
third week of development
neural groove
appears in developing tissue and by the end of the third week the sides of this groove come together and fuse along the midline to form a neural tube
neural tube defect
when the neural tube does not close
developing beural tube forms the central nervous system
cranial part forms the brain
caudal part forms the spinal cord
