week 4/2 > upper limb nerves #2 Flashcards
two groups of nerves
cranial and spinal cord
cranial nerves
- 12 pairs attached to the brain (mainly brainstem) cranial nerves
spinal cord nerve
- 32 pairs attached to the spinal cord
what does it give rise to - spinal cord nerves
to many structures but; plexuses give rise to PERIPHERAL NERVES
FUNCTIONAL COMPONENTS OF THE PNS
- enteric nervous system
- visceral sensory system
- visceral motor system
- special sensory system
- somatic sensory system
- somatic motor system
enteric nervous system
- located in the gut
influenced by ANS but functions indep.
VISCERAL SENSORY SYSTEM
- Innervates viscera, some of the fibers travel with ANS in splanchnic nerves then transfer to join the somatic sensory fibres
- some travel in cranial nerves like vagus nerve
VISCERAL MOTOR SYSTEM
- ANS
motor < mediates the internal millieu, involved in homeostasis
two divisions
parasympathetic and sympathetic
- innervate smooth and cardiac muscles and the glands
where do they distribute - parasympathetic and sympathetic
peripherally in peripheral nerves, splanchnic nerves and along blood vessels
where do the sympathetic fibers arise from
spinal cord segments T1 - L2and form the sympathetic trunk via the spinal nerves
- some of the sphlanchnic nerves arise from the sympathetic trunk
where do parasympathetic fibers arise from
from brainstem,, CN 37910 and spinal cord segments S234
SPECIAL SENSORY SYSTEM
helping to form some of the cranial nerves
- OLFACTION
VISION
HEARING
TASTE
sense the external environment
SOMATIC SENSORY SYSTEM
mediates between the external environment and CNS
where are the fibers derived from
CN 5,7,9,10 and all spinal cord derived nerves
what parts of the body does it innervate - somatic sensory system
sensory to skin, muscles, tendons, joints, connective tissues and some mucosa
- sensory modalities > pain, temperature, coarse and fine touch, proprioception
SOMATIC MOTOR SYSTEM
- motor to skeletal muscle, alpha motor neurons to the extrafusal muscle fibers, gamma motor neurons to the intrafusal muscle fibres
main role of somatic motor system
associated with activities that are conscious or voluntary
where does it process information from
external environment (hearing, sight, touch) signals to and from CNS
sensory neurons
afferent neurons > sends information to the CNS from internal glands such as glands, muscles and skin
motor neurons
efferent neurons > transmits signals from the CNS to skeletal and muscle to either directly or indirectly control muscle movement
VISCERAL MOTOR SYSTEM
responsible for coordinating involuntary behaviours such as heart rate, breathing, and digestion
DESTINATION OF THE PERIPHERAL NERVES
- muscular to muscle
- cutaneous to skin
motor/sensory, efferent/afferent
what do nerves to muscles contain
somatic motor and somatic sensory fibres
what do cutaneous nerve contain
- somatic sensory fibres > both contain sympathetic fibres to sweat glands and erector pilli muscles
what do most large peripheral nerves contain
they are called mixed nerves and contain fibres which supply both muscles and skin
what do joints receive
- their sensory innervation from nerves to nearby muscles
difference between motor and sensory
- motor > efferent fibres
- sensory > afferent fibres
SPINAL CORD SEGMENTS
- Dorsal root
- rootlets
- ventral roots
- dorsal root ganglion
- spinal nerve
- anterior primary ramus
- posterior primary ramus
- plexus
- peripheral nerve
- vertebral canal
- intervertebral foramen
do posterior rami form plexuses
no
BRACHIAL PLEXUS
where is the brachial plexus located
- in the neck and axilla
- forms from the anterior primary rami of spinal nerves C5 to C1
name the roots of brachial plexus
primary anterior rami
list the trunks of brachial plexus
upper, middle and lower
list the divisions of brachial plexus
- 3 anterior
- 3 posterior
list the cords of brachial plexus
medial, lateral and posterior
what are the larger branches named
- axillary
- radial
- musculocutaneous
- median
- ulna
list the smaller nerves of the upper limb
- long thoracic
- dorsal scapular
- nerve to subclavius
- suprascapular
- lateral pectoral
- upper subscapular
- thoracodorsal
- lower subscapular
- medial pectoral
- medial cutaneous nerve of arm
- medial cutaneous nerve of forearm
what do most of the smaller nerves innervate
the shoulder region
where do the fibres originate from
spinal cord segments (spinal nerves)
destination
- muscular
- cutaneous
mixed
