Chapter 1: Overview and Basic Concepts TB Flashcards
Regional Anatomy
-organization of the body into parts and then further subdivided into divisions
-emphasis on relationships of structures in these regions
-surface anatomy is important * -> palpable, visible, physical exam
Systemic Anatomy
-organized by organ system that work together to carry out function
-integumentary
-skeletal
-articular- joints/ligaments
-muscular
-nervous
-circulatory -> cardiovascular & lymphatic
-digestive/alimentary
-respiratory
-urinary
-genital
-endocrine
clinical (applied) anatomy
-emphasizes aspects of the structure and function of the body important to clinical practice
-regional and systemic approach
-clinical application
-case studies
gender vs sex
-sex is assigned chromosomally
-gender is an individuals intrinsic sense of their own gender
-46 chromosomes
-female- xx
-male- xy
-klinefelter syndrome- 47 chromosomes (xxy)
-jacob syndrome- 47 chromosomes (xyy)
Median / Sagittal plane
-only 1 median plane
-infinite sagittal planes
-vertical plane passing longitudinally
oblique planes
-sections that do not align with preceding planes
intermediate
-between a superficial and deep structure
-bicep is intermediate between the skin and the humerus
palmar vs dorsal
-palmar surface- anterior
-dorsal surface- dorsum- posterior
plantar vs dorsal
-plantar surface- inferior foot (sole)
-dorsal surface- dorsum- superior
pronation vs supination
-pronation- return to anatomical
-supination flipping hand over from anatomical
dorsiflexion
-toes up
plantarflexion
-tip toes
eversion
-outside part of foot up
inversion
-inside part of the foot up
lateral flexion
-lateral bending
-sway side to side
opposition vs resposition
-opposition- thumb + pinky
-reposition- thumb moves away from pinky
retrusion vs protrusion
-retrusion- jaw in
-protrusion- jaw out
abduction, adduction, extension, flexion of the thumb
-abduction- thumb moves anteriorly
-adduction- thumb moves posterior back into anatomical
-extension- thumb separates
-flexion- thumb bends towards pinky
protraction vs retraction
-protraction- shoulder forward
-retraction- shoulder backward
integumentary system
-best indicator of general health
-protection
-containment of tissues, organs, vital substances, prevents dehydration
-heat regulation- sweat glands, blood vessels, fat deposits
-sensation- superficial nerves
-synthesis and storage of vitamin D
-epidermis- superficial cellular layer, protects
-dermis- basal (deep) regenerative and pigmented connective tissue layer
-hair, nails, mammary glands, enamel of teeth
epidermis
-keratinized- tough outer surface composed of keratin
-stratified
-outer layer sheds off and is replaced by basal layer- renews 25-45 days
-avascular- nourished by underlying dermis
-supplied by afferent nerve endings that are sensitive to touch, pain, and temperature
-most nerve terminal are in dermis but some penetrate epidermis
dermis
-dense layer of interlacing collagen and elastic fibers
-fibers -> skin tone and strength of skin
-primary direction of collagen fibers -> tension lines (cleavage lines) and wrinkle lines
-deep layer of dermis- hair follicles + smooth arrector muscles + sebaceous glands
-contraction of arrector muscles -> erects hairs -> compresses sebaceous glands -> secrete oil
subcutaneous tissue
-superficial fascia
-loose connective tissue and fat
-between dermis and underlying deep fascia
-contains the deepest parts of the sweat glands, blood lymphatic vessels, and cutaneous nerves
-fat storage- thickness depends on person
-skin ligaments- consist of numerous small fibrous bands and extend through subQ tissue and attack the deep surface of the dermis to underlying deep fascia -> length determines movement of skin over deep structures
deep fascia
-dense
-organized connective tissue
-devoid of fat
-envelops most of internal body
-investing fascia- individual muscles and neurovascular bundles
-intermuscular septa- divide muscles into groups or compartments
-subserous fascia- lie between the musculoskeletal walls and serous membranes lining body cavities
deep fascia forms:
-retinacula- holds tendons in place during joint movements
-bursae- (closed sacs containing fluid)- prevent friction and enable structure to move freely over one another
facial planes
-interfascial and intrafascial
-potential spaces between adjacent fascias or fascia lined structures
axial skeleton
-head (cranium or skull), neck (cervical vertebrae), trunk (ribs, sternum, vertebrae, sacrum)
appendicular skeleton
-bones of limbs
-include pectoral (shoulder) and pelvic girdle
cartilage
-resilient
-semirigid
-avascular
-connective tissue
-cells obtain oxygen and nutrients by diffusion
-younger people have greater contribution of cartilage
articular cartilage
-cap articulating surfaces of bones participating in a synovial joint
-provides smooth, low friction gliding surfaces
bone
-living tissue
-highly specialized
-hard form of connective tissue
-chief supporting tissue of body
-protection for vital structures
-support for the body and its vital cavities
-mechanical basis for movement
-storage for salts (calcium)
-continuous supply of new blood cells
compact vs spongy (trabecular or cancellous) bone
-2 types of bone
-differences between the 2 depend on the relative amount of solid matter and the # and size of the space they contain
-bones have superficial thin layer of compact bone around central mass of spongy bone (except where the latter is replaced by a medullary (marrow) cavity
-architecture of spongy and compact bone vary upon function
medullary (marrow) cavity
-in adult bones blood cells and platelets are formed here
-also between the spicules of spongy bone
compact bone
-provides strength for weight bearing
-greatest near the middle shaft of the bone where it is liable to buckle in long bones
periosteum
-fibrous connective tissue covering that surrounds bones
-nourish tissue
-capable of laying down more cartilage or bone (healing)
-provide interface for attachment of tendons and ligaments
perichondrium
-tissue surrounding cartilage elements excluding articular cartilage
-nourish tissue
-capable of laying down more cartilage or bone (healing)
-provide interface for attachment of tendons and ligaments
long bones
-tubular structures
-humerus
-phalanges
short bones
-cuboidal
-found only in the ankle (tarsus) and wrist (carpus)
flat bones
-serve protective functions
-cranium
irregular bones
-in the face
-various shapes other than long, short, flat
sesamoid bones
-patella, kneecap
-develop in certain tendons
-protect the tendons from excessive wear and often change the angle of the tendons as they pass to their attachments
bone markings
appear wherever tendons, ligaments, and fascia are attached or where arteries lie adjacent to or enter bones
condyle
-rounded articular area
-condyles of the femur
crest
-ridge of bone
epicondyle
eminence superior to a condyle
-epicondyles of the humerus
facet
-smooth, flat area
-usually covered with cartilage
-where a bone articulates with another bone
-articular facets of a vetebrae
foramen
-passage through a bone
-obturator foramen
fossa
-hollow or depressed area
-infraspinous fossa of the scapula
line (linea)
-linear elevation
-soleal line of the tibia
malleolus
-rounded prominence
-lateral malleolus of the fibula
process
-projecting spine like part
-spinous process of a vertebrae
notch
indentation at the edge of a bone
-greater sciatic notch in the posterior border of the hip bone
protuberance
-projection of bone
-external occipital protuberance of the cranium
spine
thorn like process
-spine of the scapula
trochanter
-large, blunt elevation
-greater trochanter of the femur
tubercle
-small, raised eminence
-greater tubercle of the humerus
tuberosity
-large, rounded elevated
-ischial tuberosity of the hip bone
mesenchym
-all bones are derived from mesenchyme
-embryonic connective tissue
-intramembranous ossification- bone formation directly from mesenchyme
-endochondral ossification- bone formation from cartilage derived from mesenchyme
intramembranous ossification
-membranous bone formation
-directly from mesenchyme
-mesenchymal models of bone form during the embryonic period
-begins in fetal period
endochondral ossification
-cartilaginous bone formation
-cartilage models of bones form from mesenchyme during fetal period, and bone replaces most of the cartilage
-mesenchymal cells condense and differentiate into chondroblasts -> dividing cells in growing cartilage tissue -> cartilaginous bone model
-cartilage calcifies and periosteal capillaries grow into the calcified cartilage of the bone model and supply its interior
-blood vessels, with associated osteogenic (bone-forming) cells form 0> periosteal bud
primary ossification center
-bone tissue it forms replaces most of the cartilage in the shaft of the bone model
-shaft of bone ossified -> diaphysis
secondary ossification centers
-appear in other parts of the developing bone after birth
-parts ossified from here -> epiphyses
-epiphysial arteries grow into developing cavities with associated osteogenic cells
metaphysis
-flared part of diaphysis nearest to epiphysis
Continual growth
-bone formed in primary center in diaphysis does not fuse with bone formed from secondary centers until bone reaches adult size
-cartilaginous epiphyseal plates intervene between diaphysis and epiphyses
-growth plates are eventually replaced by bone : diaphysial and epiphysial
-diaphysis fuses with epiphyses -> bone growth ceases
-seam formed during synostosis is dense and appears in radiographs -> epiphysial line`
nutrient arteries
-1 or more per bone
-arise outside periosteum, pass through shaft via nutrient foramina and split in the medullary cavity into longitudinal branches
-supply bone marrow, spongy bone, and deeper portions of the compact bone
periosteal arteries
-small branches from periosteal arteries supply most of compact bone
-if periosteum is removed bone will die
metaphysial and epiphysial arteries
-supply the ends of bones
-arise mainly from arteries that supply joints
bone nerves
-periosteum richly supplied with sensory nerves
-periosteal nerves- carry pain fibers
-periosteum is sensitive to tearing or tension -> acute pain from fracture
-vasomotor nerves cause constriction or dilation of blood vessels -> regulates blood flow through bone marrow
3 joints
-fibrous
-cartilaginous
-synovial
fibrous joints
-united by fibrous tissue
-movement depends on length of fibers uniting articulating bones
-syndesmosis- unties bones with sheet of fibrous tissue, either a ligament or fibrous membrane -> movable
-gomphosis- type of fibrous joint found in teeth
cartilaginous joints
-united by hyaline cartilage (primary) or fibrocartilage (secondary)
-synchondroses- permit growth of length of bone and allow slight bending until epiphyseal plate converts to bone
-symphyses- strong slightly mobile joints
synovial joints
-cavity
-contains a small amount of synovial fluid
-nourishing articular cartilage and lubricating joint surfaces
-most common
-reinforced by accessory ligaments that either separate (extrinsic) or are thickened part of the joint capsule (Intrinsic)
-some have fibrocartilaginous articular discs or menisci present when the articulating surfaces of the bones are incongruous
-6 types classified by shape of the articulating surface and/or type of movement they permit
6 types of synovial joints
-pivot- uniaxial, rounded process fits into bony ligamentous socket -> rotation- ex. median atlantoaxial joint
-ball and socket- multiaxial, rounded head fits into concavity- ex. hip joint
-condyloid- biaxial, permit flexion, extension, abduction, adduction, circumduction- ex. metacarpophalangeal joint
-saddle- biaxial- ex. carpometacarpal joint
-hinge- uniaxial, permit flexion and extension- ex. elbow
-plane- usually uniaxial, gliding or sliding- ex. acromioclavicular joint
vasculature of joints
-receive blood from articular arteries that arise from vessels around joint
-anastomose (communicate) to form networks to ensure continuous blood supply throughout its range of movement
-articular veins located in joint capsules mostly synovial membrane
-rich nerve supply
-in distal parts of limbs, articular nerves are branches of cutaneous nerves supplying overlying skin
-nerves that supply muscles supply and move joints
-many pain fibers in fibrous layer of joint capsule
-joints transmit proprioception
hilton law
-nerves supplying a joint also supply the muscles moving the joint and the skin covering their attachments
muscle fibers
-muscle cells
-long narrow
-contractile
-1. skeletal striated muscle
-2. cardiac striated muscle
-3. smooth muscle
skeletal muscle
-contractile portion-skeletal striated muscle (heads or bellies)
-noncontractile portion- collagen bundles: tendons and aponeuroses
-most are attached directly or indirectly through tendons and aponeuroses to bones, cartilages, ligaments, or fascia
-some are attached directly to organ- eye, skin (face), mucous membranes (tongue)
-provide static support, give form to body, provide heat
pennate muscles
-feather like in arrangemnt of their fascicles
-unipennate, bipennate, multipennate
fusiform muscles
-spindle shaped
-round, thick belly, tapered ends
parallel muscles
-fascicles lie parallel to the long axis of the muscle
-flat muscles with parallel fibers often have aponeuroses
convergent muscles
-have broad attachment from which the fascicles converge to a single tendon
circular muscles
-surround body opening or orifice
-constricting it when constracted
digastric muscles
-feature two bellies in series, sharing a common intermediate tendon
contraction of muscles
-shorten 70% of resting length
-long, parallel fascicle shorten the most -> high ROM, low strength
-short, wide pennate muscles- shorten less, more powerful
-attachments of muscles are usually described as the origin (proximal) and insertion (distal- moveable)
-some muscles can act in both directions
reflexive contraction
-automatic, nonvoluntary
-respiratory movement of diaphragm
tonic contraction
-slight contraction
-does not produce movement or active resistance
-gives muscle firmness
-assists in stability of joints and maintenance of posture
phasic contraction
-isometric contraction- muscle length remains the same (no movement), tension increased above tonic levels (holding abduction)
-isotonic contractions- muscles changes length to produce movement -> concentric and eccentric contractions
-concentric- movement occurs due to muscle shortening (abduction)
-eccentric- progressive lengthening of contracted muscle (adducted)
components of muscle
-structural unit of a muscle - muscle fiber
-endomysium- connective tissue covering individual muscle fibers
-perimysium- covers a group of fiber bundles
-epimysium- covers entire muscle
-motor unit- motor neuron + muscle fibers it controls
-motor units with more fibers -> less precise
prime mover or agonist
-main muscle responsible for producing a specific movement of the body
-concentric contraction
fixators
-steady the proximal parts of a limb while movements are occurring in distal parts
synergist
-complements the action of prime movers
-by preventing movement of the intervening joint when a prime mover passes over more than one joint
antagonist
-muscle that opposes the action of a prime mover
-as prime mover contracts -> antagonist progressively relaxes
-produces a smooth movement
cardiac striated muscle
-myocardium
-some is in the aorta, pulmonary vein, superior vena cava
-nonvoluntary
-rhythmic contractions generated intrinsically by pacemaker nodes
-rate is influenced by autonomic nervous system
-propagated myogenically (muscle fiber to muscle fiber) rather than direct nerve stimulation
smooth muscle
-absence of microscopic striations
-middle coat or layer of walls of most blood vessels and muscular part of the wall of digestive tract and ducts
-skin- arrector muscles
-eyeball- pupil size
-innervated by ANS
-involuntary
-regulates size of lumen and tubular structures
-peristaltic waves
capillary beds
-minute but numerous thin walled capillaries form a capillary bed
-interchange of oxygen, nutrients, waste products, substances with extracellular fluid
layers of vessels
-tunica intima- thin endothelial lining
-tunica media- middle smooth layer
-tunica adventitia- outer connective tissue coat
large elastic arteries
-conducting arteries
-many elastic layers
-aorta and its branches
-elasticity in these arteries maintains blood pressure
-allows to expand when heart contracts and return to normal between contractions
medium muscular arteries
-distributing arteries
-walls are mainly smooth muscle circularly arranged
-femoral artery
-decrease their diameter (vasoconstrict) -> regulates flow of blood to different parts of body as required
small arteries/arterioles
-narrow lumina
-thick muscular walls
-degree of arterial pressure is mainly regulated by degree of tonus (firmness) in smooth muscle of arteriolar walls
-if tonus in arteriolar wall is above normal -> hypertension
venous plexus
-venules unite to form larger veins
-dorsal venous arch
large veins
-SVC
-IVC
-wide bundles of longitudinal smooth muscle
-well developed tunica adventitia
-veins in general more frequently anastomoses
venous blood return to heart
-vascular sheath- accompanying veins (to arteries) surround arteries in a branching network
-veins are stretched and flattened as the artery expands during contractions of heart -> Assists in venous blood return
-Musculovenous pump- skeletal muscles compress deep veins -> milking blood superiorly towards heart
-multiple perforating veins penetrate deep fascia to shunt blood to deep veins and assist in venous return
arteriovenous anastomoses (AV shunts)
-capillaries are endothelial tubes
- the small arteries and veins connect directly proximal to capillary beds (ex. fingers)
-permit blood to pass directly from arterial to venous side
-numerous
-important role in conserving body heat
lymphatic plexuses
-networks of small lymphatic vessels
-lymphatic capillaries that originate in the extracellular spaces of most tissues
lymphatic vessels (lymphatics)
-nearly body wide network of thin walled vessels with abundant valves
-originate from lymphatic plexuses along where lymph nodes are located
-occur almost everywhere blood capillaries are found (except teeth, bone, bone marrow, CNS)
lymph nodes
-small masses of lymphatic tissue through which lymph is filtered on its way to the venous system
lymphocytes
-circulating cells of the immune system that react against foreign materials
lymphoid organs
-sites that produce lymphocytes
-walls of the digestive tract, spleen, thymus, lymph nodes, myeloid tissue in red bone marrow
lymph traveling
-after traversing 1 or more lymph nodes….
-lymph enters lymphatic trunks -> trunks unite to form right lymphatic duct or thoracic duct
right lymphatic duct
-drain lymph from bodys right upper quad (right head, neck, thorax, right upper limbs)
-duct ends in angular junction of the right subclavian and internal jugular veins called right venous angle
thoracic duct
-drains lymph from remainder of body
-begins in abdomen as a dilatation, the cisterna chyli, and ascends through the thorax and enters the junction of the left internal jugular and left subclavian veins called the left venous angle
superficial lymphatic vessels
-in the skin and subcutaneous tissue -> drain into deep lymphatic vessel
lymphatic system additional purposes
-absorption and transport of dietary fat- lymphatic capillaries (lacteals) receive all absorbed fat (chyle) from the intestine and convey it through thoracic duct to venous system
-formation of a defense mechanism for the body- foreign protein drains from infected area - > antibodies formed by lymphocytes and dispatched to infected area
nervous system divisions
-CNS- brain + spinal cord
-PNS- nerve fibers + cell bodies outside CNS
-sensory (afferent)- carries info to CNS
-motor (efferent)- carries stimulatory impulses from CNS to effector organs (muscles or glands)
-sensory and motor have visceral and somatic (voluntary) components
-somatic motor- supplies skeletal
-visceral motor- (ANS) supplies smooth muscle, glands, and conducting system of heart
-somatic sensory- carries sensation like touch and pain from skin, muscles, joints
-visceral sensory- carries sensation (pain and reflex) from viscera of body cavities
nervous tissue
-neurons (Nerve cells)
-neuroglia (glial cells)
neurons
-structural and functional units of NS
-cell body, dendrites, axon
-communicate at synapses
-communicate by means of neurotransmitters- chemical agents released or secreted by one neuron -> Excites or inhibits another neuron
myelin
-layers of lipid and protein substances
-forms myelin sheath around some axons
-greatly increases velocity of impulse conduction
neuroglia
-glial cells or glia
-approx 5 times as abundant as neurons
-nonneuronal
-nonexcitable
-form major component (scaffolding) of nervous tissue
-support, insulate, nourish neurons
CNS
-brain + spinal cord
-integrate and coordinate incoming and outgoing neural signal
-carry out thinking and learning
nucleus
-collection of nerve cell bodies in the CNS
tract
-bundle of nerve fibers (axons) connecting neighboring or distant nuclei of the CNS
gray vs white matter
-nerve cell bodies are in and constitute gray matter
-interconnecting fiber tract systems from white matter
-gray matter is H shaped embedded in matrix of white matter
-struts of H are the horns -> posterior (dorsal) and anterior (ventral) gray horns
meninges
-meninges and CSF surround and protect CNS
-brain and spinal cord are covered by delicate, transparent pia mater
-CSF in the subarachnoid space between pia and arachnoid mater
-dura mater- thick, close to internal aspect of bone
-dura of the spinal cord is separate from vertebral column by fat filled space -> epidural space
PNS
-nerve fibers and nerve cell bodies outside CNS that connect CNS with peripheral structures
-peripheral nerves consist of bundles or nerve fibers, their connective tissue coverings, and blood vessels -> vasa nervorum
-nerve fibers- axon, single process of a neuron, neurolemma, cell membranes of schwann cells, endoneurium (connective tissue sheath)
-peripheral nerves are strong and resilient bc they are supported and protected by 3 coverings: endoneurium, perineurium, epineurium
myelinated nerve fibers
-neurolemma has a myelin sheath
-consists of continuous series of schwann cells enwrapping an individual axon
unmyelinated nerve fibers
-neurolemma consists of multiple axons separately embedded within the cytoplasm of each schwann cell
-schwann cells do not produce myelin
-most fibers in cutaneous nerves (skin) are unmyelinated
endoneurium
-delicate connective tissue sheath that surrounds the neurolemma cells and axons
perineurium
-layer of dense connective tissue that encloses a fascicle (bundle) of peripheral nerve fibers
-provides an effective barrier against penetration of the nerve fibers by foreign substances
epineurium
-thick connective tissue sheath that surrounds and encloses a bundle of fascicles
-forms the outermost covering of the nerve
-includes fatty tissues, blood vessels, and lymphatics
ganglion
-collection of nerve cell bodies outside the CNS
-motor (autonomic) and sensory ganglia
cranial nerves
-peripheral nerves are either cranial or spinal
-12 pairs
-11 pairs of cranial nerves arise from brain
-1 pair (11) from superior part of the spinal cord
-exit the cranial cavity through foramina in the cranium
spinal nerves
-31 pairs
-8 cervical
-12 thoracic
-5 lumbar
-5 sacral
-1 coccygeal
-arise from spinal cord and exit through intervertebral foramina in the vertebral column
somatic nervous system
-somatic parts of CNS and PNS
-provides general sensory and motor innervation to all of body (except viscera, smooth muscle, glands)
-somatic sensory fibers transmit sensations of touch, pain, temperature, and position
-somatic motor fibers stimulate skeletal (voluntary) muscle only -> voluntary and reflexing movements
spinal nerve
-somatic sensory and motor fibers, visceral motor fibers, connective tissue coverings, vasa nervorum
-arise from spinal cord by nerve rootlets which converge to form 2 nerve roots
-anterior (ventral) root- consists of motor (efferent) fibers passing from nerve cell bodies in the anterior and lateral horns of spinal cord gray matter to effector organs located peripherally
-posterior (dorsal) root- consists of sensory (afferent) fibers that convey neural impulses to CNS from sensory receptors in various parts of the body (skin)
-posterior root carries general sensory fibers to the posterior horn of the spinal cord
-anterior and posterior root unite at the intervertebral foramen to form a spinal nerve -> divides into 2 rami (branches) -> posterior ramus and anterior ramus
-branches of mixed spinal nerve - anterior and posterior rami carry both motor and sensory nerves
posterior rami
-supply nerve fibers to synovial joints of the vertebral column, deep muscles of the back, and overyling skin
anterior rami
-supply nerve fibers to the much larger remaining area, consisting of anterior and lateral regions of the trunk and the upper and lower limbs arising from them
spinal nerve: somatic sensory fibers
-sensory fibers transmit sensations from body to CNS
-exteroceptive sensations- pain temperature, touch, pressure from skin
-proprioceptive sensations- subconscious sensations regarding body in space from muscles, tensons, joints
-dermatomes
dermatome
-unilateral area of skin innervated by the general sensory fibers of single spinal nerve
spinal nerve: somatic motor fibers
-transmit impulses to skeletal (voluntary) muscles
-unilateral muscle mass receiving innervation from somatic motor fibers conveyed by a spinal nerve
-myotomes
-each skeletal muscle innervated by somatic motor fibers of several spinal nerves -> myotome has several segments
myotome
-unilateral muscle mass receiving innervation from somatic motor fibers conveyed by a spinal nerve
-unilateral portion of skeletal muscle
-grouped by joint movement to facilitate clinical testing
spinal nerve: visceral motor fibers
-sympathetic part of ANS are conveyed by all branches of spinal nerves to the smooth muscle of blood vessels and to sweat glands and arrector pili
-visceral motor fibers of the PNS part of ANS and visceral afferent fiber have very limits association with spinal nerves
vasa nervorum
-spinal nerve
-blood vessels supplying the nerves
ANS
-aka visceral motor system
-visceral efferent (motor) fibers stimulate smooth muscle in walls of blood vessels, organs, cardiac, and glands
-accompanied by visceral afferent (sensory) fibers to regulate visceral functions
visceral motor innervation
-efferent nerve fibers and ganglia of the ANS are organized into 2 divisions:
-1. sympathetic (thoracolumbar) division
-2. parasympathetic (craniosacral) division
-divisions innervate same structures with opposite effect
-impulses from CNS involve 2 neurons in both sympathetic and parasympathetic
-location of the presynaptic cell bodies and which nerves conduct the presynaptic fibers from the CNS -> distinguish symp from para
sympathetic (thoracolumbar) division
-ANS division
-catabolic
-fight or flight
-neurotransmitter- norephinephrine (except for sweat glands)
-reaches almost all parts of body - not avascular -> cartilage and nails
-presynaptic fibers are shorts and post are longer (extend to all parts)
-main function is to regulate blood vessels- dilate, constrict
parasympathetic (craniosacral) division
-anabolic
-conserving energy
-ANS division
-neurotransmitter- acetylcholine
presynaptic (preganglionic) neuron
-in the gray matter
-axon synapses on cell body of postsynaptic (postganglionic) neuron
postsynaptic (postganglionic) neuron
-located outside the CNS in autonomic ganglia
-postsynaptic fibers terminating on the effector organ (smooth muscle, cardiac, glands)
sympathetic visceral motor innervation
-presynaptic neurons are in the intermediolateral cell columns (IMLs) or nuclei of the spinal cord- lateral horns
-paired IMLs are part of gray matter between T1-L2+L3
-postsynaptic cell bodies occur in 2 places: paravertebral and prevertebral ganglia
-axons of presynaptic neurons leave spinal cord through anterior roots and enter anterior rami of spinal nerves T1-L2+L3
-after entering rami presynaptic sympathetic fibers leave anterior rami and pass to sympathetic trunks through white rami communicates
paravertebral ganglia
-form right and left sympathetic trunks (chains) on each side of vertebral column that extends the length of the column
-superior cervical ganglion- superior paravertebral ganglion lies at the base of cranium
-ganglion impar- forms inferiorly where 2 trunks unite at level of coccyx
prevertebral ganglia
-in the plexuses that surround origins of main branches of abdominal aorta
course of presynaptic fibers within sympathetic trunks
-1 of 4 possible courses after entering sympathetic trunks
-1. ascend
-2. descend in sympathetic trunk to synapse with postsynaptic neuron of higher or lower paravertebral ganglion
-3. enter and synapse immediately with postsynaptic neuron of paravertebral ganglion at that level
-4. pass through sympathetic trunk without synapsing continuing on within abdominopelvic splanchnic nerve to reach prevertebral ganglia
presynaptic sympathetic fibers
-provide autonomic innervation within head, neck, body wall, limbs, and thoracic cavity
-follow 1 of 3 courses after entering sympathetic trunks:
-1. ascend
-2. descend in sympathetic trunk to synapse with postsynaptic neuron of higher or lower paravertebral ganglion
-3. enter and synapse immediately with postsynaptic neuron of paravertebral ganglion at that level
-> synapses within paravertebral ganglia
-presynaptic sympathetic fibers innervating viscera within abdominopelvic cavity follow 4th (-4. pass through sympathetic trunk without synapsing continuing on within abdominopelvic splanchnic nerve to reach prevertebral ganglia)
postsynaptic sympathetic fibers
-outnumber presynaptic fibers
-those in neck, body wall, limbs, pass from paravertebral ganglia of sympathetic trunks to adjacent anterior rami of spinal nerves through gray rami communicantes
-enter all branches of each of the 31 pairs of spinal nerves including posterior rami to stimulate contraction of blood vessels and arrector muscles
-Postsynaptic sympathetic fibers that perform these functions in the head have their cell bodies in the superior cervical ganglion at the superior end of the sympathetic trunk -> pass from ganglion by means of a cephalic arterial branch -> form periarterial plexuses of nerves -> follows branches of the carotid arteries or pass to CNs to reach their destination in the head
-components of all branches of all spinal nerves -> innervate all bodys blood vessels, sweat glands, arrector, visceral structure
splanchnic nerves
-convey visceral efferent (autonomic) and afferent fiber to and from viscera of body cavities
-postsynaptic sympathetic fibers for viscera and thoracic cavity pass through cardiopulmonary splanchnic nerves to enter cardiac, pulmonary, and esophageal plexuses
-presynaptic sympathetic fibers innervation abdominopelvic cavity pass to prevertebral ganglia through abdominopelvic splanchnic nerves -> synapse in prevertebral ganglia
-some that some synapse here terminate directly on cells in medella of suprarenal gland
-postsynaptic fibers form prevertebral ganglia form periarterial plexuses -> follow branches of abdominal aorta to reach destination
suprarenal gland
-suprarenal medullary cells function as special type of postsynaptic neuron that release neurotransmitters into bloodstream to circulate throughout body producing widespread sympathetic response
-(rather than release onto the cells of specific effector organ)
parasympathetic visceral motor innervation
-presynaptic are located in 2 sites: cranial and sacral site
-cranial site- from the gray matter of brainstem, fibers exit CNS within CN 3, 7, 9, 10 -> cranial parasympathetic outflow
-sacral site- from gray matter of sacral segments of the spinal cord (S2-S4), the fibers exit CNS through anterior roots of spinal nerves S2-S4 and the pelvic splanchnic nerves that arise from anterior rami -> sacral parasympathetic outflow
-weaker than sympathetic -> only head, visceral cavities of trunk, and erectile tissues of genitalia
cranial outflow
-parasympathetic innervation of head
-through vagus nerve (10) -> innervation of thoracic and abdominal viscera
-GI
-sacral outflow supplies descending and sigmoid colon and rectum from GI
parasympathetic synapse
-4 discrete pairs of ganglia in the head
-elsewhere, pre and post synapse in or on wall of target organ
-pre are long- extend from CNS to effector organ
-post is short running from ganglion located near or in effector organ
enteric nervous system
-postsynaptic parasympathetic motor neurons of the GI tract
-ENS
-autonomous without connection to CNS
-2 interconnected plexuses within the walls of GI tract: myenteric plexus of wall musculature and submucosal plexus, deep to and serving the gut lining mucosa
-plexus include intrinsic primary afferent neurons that receive local input and stimulate motor neurons -> local reflex -> integrate exocrine and endocrine secretion, vasomotion, micromotility, and immune activity of gut
-modulated by input from extrinsic parasympathetic and sympathetic sibers
visceral afferent sensation
-info is integrated in CNS -> trigger visceral or somatic reflexes
-visceral reflexes regulate BP and chemistry by altering heart and respiratory rate and vascular resistance
-visceral sensation that reaches conscious level is poorly localized pain- hunger, nausea -> strong ones- > spams, contractions, distention
conventional radiography (X-ray)
-highly penetrating beam
-transilluminates
-shows tissue of differing density of mass
-dense- absorbs more -> transparent area -> radiopaque
-less dense- radiolucent
-posterior to anterior (PA projection)
-anterior to posterior (AP projection)
-lateral radiographs- radiopaque letters (R or L) are used to indicate the side
computerized tomography (CT)
-transverse
-beam of x-rays passed through body
-amount of radiation absorbed by diff types of tissue varies with fat, bone, and water
ultrasonography
-visualization of superficial or deep structure in body
-records pulses of ultrasonic waves reflecting off tissues
-can be viewed in real time
-standard method from embryo and fetus bc no radiation
magnetic resonance imaging (MRI)
-better for tissue differentiation
-reconstruct the tissue in ANY PLANE (diff from CT)
-magnetic field
-body pulsed with radio waves
-signal emitted from pts tissues are stored in computer
-can vary by controlling how radiofrequency pulses are sent and received
-scanners can be gated or paced to see blood in real time
-MR angiography and venography use MRI and dyes to image blood vessels
-MR spectroscopy- investigate metabolic changes in brain after stroke, tumor, etc.
positron emission tomography (PET)
-uses cyclotron produced isotopes of extremely short half life that emit positrons
-evaluate physiological functions of organs
-areas of increased brain activity will show selective uptake of injected isotope
