anatomy yr 2 Flashcards
lateral fissure
separates the temporal lobe and frontal lobe
central sulcus
separates frontal lobe and parietal lobe
whats contained in the frontal lobe
- Prefrontal-area – planning complex movements and thinking
- Motor cortex – controlling muscles
o Speech production (Broca’s Motor speech area) – specialised area of motor area
whats contained in the parietal lobe
- Somato-sensory area – receiving sensory information from skin/joints etc
what’s contained in the temporal lobe
- Auditory
- Language, understanding, intelligence
- Behaviour, emotions, motivation (small bit is partly in the frontal lobe)
- wernickes speech area
what are brodmann’s areas
- Brodmann stained areas of the brain and looked at the distribution of neurones across brain tissues
- Gave each area of tissue a number
- These numbers predict the functional areas of the brain
- Practically overlap the functional areas of the brain…
association, commissural and projection fibres
Association Fibres (within same hemisphere)
Commissural Fibres (between hemispheres) eg corpus callosum
Projection Fibres (cortex to sub-cortical areas) eg internal capsule
diancephalon
Position - deep in middle of brain
- Below the corpus callosum and above the top of the brainstem
- Subconscious level
- Sub regions – all contain the name thalamus
areas of the diancephalon
o Epithalamus- contains the pineal gland (secretes/generates melatonin)
o Thalamus – one structure with 2 sides (L and R) looks like 2 birds egg
Sifting and sorting information
o Subthalamus – sits below thalamus, not seen clearly above
Motor control
o Hypothalamus – master regulator in partner with pituitary gland (intimate physical and vascular relationship)
Pituitary gland is not seen in dissected brains as its pulled away during dissection
parts of the brainstem
midbrain
pons
medulla
what divides the cerebellum medially
the vermis
what are the ridges of the cerebellum called
folia
what are the 3 white axon tracts linking the cerebellum to the brainstem
- Superior Peduncle (link it to midbrain)
- Middle Peduncle (link to pons)
- Inferior Peduncle (link to medulla)
what level does the brain become the spinal cord
the foramen magnum roughly
ventral grey horns vs dorsal grey horns
Ventral grey horns
- Motor activities (signal going out)
- Encased in white matter
- Don’t reach ventral edge of cord
Dorsal grey horns
- Sensory activities (signals coming in)
- Reach right up to the edge (dorsal surface) of cord
falx cerebri
fold of dura matter in the midline of skull between hemispheres, sits in great longitudinal fissure
tentorium cerebelli
partition between occipital lobes and cerebellum
where do the carotid arteries branch from
brachiocephalic trunk
where do the vertebral arteries branch from
subclavian artery
what arteries do the internal carotid arteries give rise to
middle and anterior cerebral artery
what are the 3 communicating arteries
left posterior
right posterior
anterior
what do the vertebral arteries give rise to
unite to form the midline basilar artery
this terminates as a pair of post. cerebral arteries
venous drainage
- no valves
- occurs through gravity
- drained through dura venous sinuses
since dura is double layered…
- 2 membranes come apart to form a space which is the sinuses that drain the brain
- via internal jugular veins
different dura venous sinuses
superior sagittal sinus
- runs along falx cerebri
transverse sinuses
- splits at back of the head
sigmoid sinuses
- arise from transverse sinuses and drains to jugular veins
ventricles of the brain
lateral ventricles
- left and right
- anterior, posterior, inferior horns
- chambers comes together in midline & intraventricular foramen (FORAMEN OF MUNRO) connects them to 3rd ventricle
3rd ventricle
- connects through CEREBRAL AQUEDUCT to 4th ventricle
4th ventricle
- sits between the pons of the brainstem in front and cerebellum of brainstem behind
what are the specialised cells called within the ventricles
ependymal cells
what structure secretes CSF
choroid plexus
where and what are the arachnoid granulations
in the superior sagittal sinus
- they suck up CSF
what’s the small inferior part of the cerebellum called
the flocculondular lobe
what divides the anterior and posterior lobe of the cerebellum
primary fissure
what are the 3 main divisions of the cerebellum evolutionary
central part – vestibulocerebellum (archicerebellum)
o fastigal nucleus
2 way connections with vestibular nucleus
Connected to where one is positioned in space, and movement in space
middle part – spinocerebellum (paleocerebellum)
o interposed nucleus
spino-cerebellar connections with the spinal cord
deals with posture and gait
outer part – pontocerebellum (neocerebellum)
o dentate nucleus
connected with pons and neocortex
uniquely large in humans
deals with fine motor control eg hand movements
what are the 3 cellular layers of the cerebellum
outer - molecular layer
- stellate cells, basket cells
middle - piriform layer
- purkinje cells
inner - granular layer
- granule cells, golgi cells
what fibres are associated with what layers of the cerebellum (input)
- Granular layer through mossy fibres
- Molecular layer through climbing fibres
spinal cord tracts that send info to the cerebellum
a. Posterior spino-cerebellar
b. Cuneocerebellar
c. Anterior spinocerebellar
d. Rostral spinocerebellar
head, neck and brainstem tracts that send info to the cerebellum
a. Oliviocerebellar
b. Tectocerebellar
c. Pontocerebellar
d. Reticulocerebellar
e. Trigeminal nerve
where does the cerebellum send info (efferents)
- vestibular nuclei
- reticular formation
- red nucleus
- ventrolateral thalamus
symptoms of ataxic syndrome (cerebellar problem)
- Ataxia of upper and lower limbs
o Clumsiness of motor movement - Truncal ataxia
o In-coordination of postural sense – unsteadiness and falls - Gait ataxia
o In-coordination of walking - Dysarthria – speech coordination
- Nystagmus – eye incoordination
lenticulo-striate arteries
Supply deep brain nuclei ie basal ganglia and thalamic nuclei
lipohyalinosis
- Degeneration process initiated by fibrinoid necrosis
- Segmental arteriole disorganisation
arteriosclerosis
- Concentric hyaline wall thickening of small arteries and arterioles
- Deeply seated intracerebral haematoma associated with ht
- Common sites
o Basal gangla
o Brain stem
o Cerebellum
lobar haematoma
commonest cause - beta-amyloid immunohistochemistry
- alzheimers disease predisposes
venous infarction
- Sagittal sinus thrombosis o Oral contraceptives o Dehydration o Meningitis - Cortical vein thrombosis o meningitis
what are the 2 divisions of the dorsal column
fasciculus gracilis
- lower body/ limbs
fasciculus cuneatous
- upper body/ limbs
what is a key feature of being in the caudal medulla
internal arcuate fibres
- these are dorsal column fibres that are decussating in the medulla
- pass into a white-matter tract known as the medial lemniscus pathway
what happens to medial lemniscus pathway in the thalamus
in diacephalon…
- 3rd order neurone cell bodies are found in the VPL (ventral posterolateral nucleus of the thalamus)
- then info proceeds to the primary somatosensory cortex
what part of the internal capsule do the dorsal column/ medial lemniscus axons pass through
posterior limb
where do the 1st order neurones synapse onto 2nd order cell bodies in the spinothalamic pathway
- immediately in the spinal cord
- substantia gelatinosa and
- nucleus proprius
what is the white matter bridge the spinothalamic fibres use to decussate
ventral white commisure
therefore the sensory info in the spinal cord is organised into…
o Ipsilateral info about discrimitive touch and proprioception
o Contralateral info about pain, non-discrimitive touch, and temperature
what pathway do spinothalamic fibres pass through in the midbrain
spinal lemniscus
how many orders are there in the spinocerebellar pathway
2
dorsal spinocerebellar pathway
- enters at dorsal part of spinal cord via dorsal rootlets
- enter spinal cord at dorsal horn of spinal cord
- 2nd order neurone in middle region of grey matter of spinal cord (between ventral and dorsal horns)
- this area known as CLARKES COLUMN
- 2nd order neurone passes axon into dorsal spinocerebellar tract into the medulla
through INFERIOR PEDUNCLE
ventral spinocerebellar pathway
- enters through dorsal rootlets
- synapses immediately with 2nd order neurone in clarke’s column
- 2nd order neurone decussates in the ventral white commisure
- entering ventral part of spinocerebellar tract and ascending to the pons
- crosses back over behind the brainstem at this point into the original side
- goes through SUPERIOR CEREBELLAR PEDUNCLE
what are the subregions of the trigeminal nerve nucleus
Mesencephalic nucleus
Chief sensory nucleus
Nucleus of the spinal tract of the trigeminal
what’s the pathway of the second neurone of the trigeminal nerve
- decussates in brainstem then heads up to the thalamus
- in the internal capsule the 3rd order nucleus is in the VPM NUCLEUS (ventral posteromedial nucleus)
important dermatome levels
C3 and C4
o Area around the neck
o Expect the collar of a shirt
C6
o Skin of thumb
C7
o Middle finger
C8
o Skin of little finger
T4
o Nipples in male
T10
o Umbilicus – belly button
L4
o Front of Knee
whats the difference between cranial nerves I & II vs cranial nerves III-XII
olFactory and optic nerves (I & II)
o Direct outgrowths of the brains
o Same structure as CNS – same myelin
Other cranial nerves (III – XII)
o Similar to PNS
o When they leave the CNS have a peripheral nerve type structure
what does damage to the oculomotor nerve (III) result in
o Result in ipsilateral eye being deviated downward and laterally
o Ptosis
o Fixed dilated pupil
o May be damaged due to raised intracranial pressure with tentorial herniation, or disorders involving the cavernous sinus
what eye muscles does the oculomotor nerve supply
- superior rectus
- inferior rectus
- medial rectus
- inferior oblique
what does the trochlear nerve (IV) supply
superior oblique
- if damaged = diplopia (double vision) looking downwards and medially
what does the abducens nerve (VI) supply
- supplies the lateral rectus muscle
- when damaged results in diplopia (double vision) looking laterally
what are the 3 branches of the trigeminal nerve
o Ophthalmic
o Maxillary
o Mandibular
Also contains efferent motor fibres that supply muscles of mascication
what are the 3 sensory nuclei of the trigeminal nerve
o Mesencephalic; proprioception form jaw
o Chief sensory nucleus and spinal nucleus; 2nd order neurones from spinothalamic pathway
- These fibres decussate and pass to thalamus
cavernous sinus
- Brings together III, IV, V, VI cranial nerves
- Dural venous sinus
- Lies in middle of cranial fossa
cavernous sinus syndrome
o Give rise to variable ocular palsies and upper trigeminal sensory loss
o Caused by trauma, neoplasia, thrombosis, inflammatory conditions
facial nerve (VII) afferent/ efferent supply
- muscles of facial expression
- sensory info from external ear (geniculate nucleus)
- 2/3rds of tongue
UMN vs LMN lesion effects on facial nerve
UMN
- upper facial muscles relatively well preserved due to bilateral innervation of the facial nucleus
- lower facial muscles paralysed
LMN
- paralysis of both upper and lower facial muscles
where are cell bodies of lower motor neurones
ventral grey horn
where are there enlarged ventral grey horns and why
- cervical enlargement
- lumbar-sacral enlargement
extra no.s of LMN cell bodies to supply upper and lower limbs
what are the 2 types of motor neurone axons and whats the difference
alpha and gamma
gamma
- small group of MN that supply muscle spindle
alpha
- fastest conduction velocity
- largest diameter
- always myelinated
- don’t want to delay of getting info from CNS to muscles
NMJ
one per muscle fibre
- but indiv. motor neurone can innervate multiple muscle fibre (motor unit)
- fine control = small motor unit
- power = big motor unit
almost always cholinergic fibres - Ach
only needs one action potential to activate (not summative)
where is the primary motor cortex
- in the prefrontal gyrus
- has 6 layers of neurones (lamina)
what do the corticospinal UMN travel through from the PMC to internal capsule
corona radiata (looks like rays of sun)
whats are the parts of the internal capsule
anterior limb
genu
posterior limb
what part of the internal capsule do the corticospinal tracts cross through
posterior limb
- beside ascending sensory axons
arranged so head and neck fibres are up towards the genu and lower limb fibres are at the bottom in the RETRO LENTICULAR PART
what are the white matter tracts the corticospinal fibres travel down in the midbrain
crus cerebri
- /basis pedunculi
what are the corticospinal fibres called once they enter the pons
transverse pontine fibres which criss-cross side to side
thereby separating up UMN and segregating them into sub-tracts
- called PONTINE SPINAL TRACTS
what are the corticospinal tracts called in the medulla
the pyramids
- 75-90% of fibres cross here
- usually at caudal (lower) end of medulla
what different fibres are int he ventral and lateral corticospinal tracts
ventral
- those that remain ipsilateral
lateral
- those that decussate
rubrospinal tract
contralateral
- from red nucleus in midbrain
- alternative route for higher centre LMN control
vestibulospinal tract
ipsilateral
- from vestibular nuclei in pons and medulla
- 2 bundles (medial and ventrolateral)
- receive info from vestibular apparatus in inner ear
- rapid feedback on pos. and movement of head
tectospinal tract
contralateral
- from superior colliculus in midbrain
- relay centre on visual pathways
reticulospinal tract
ipsilateral and bilateral
- from reticular nuclei in brainstem
- 3 potential tracts (lateral, medial, ventral)
- volume control on motor activity
- complex
clinical affects of UMN loss
- no profound muscle atrophy
- spasticity
- pos. “babinksi” reflex (big toe dorsiflexion)
LMN still intact which is why muscle not paralysed and doesn’t waste away bc LMN still sends signals to muscle
clinical affects of LMN loss
- connectivity between NS and muscle lost
- weak or paralysed
- profound muscle atrophy
- tendon reflexes are weak or absent
- fibrillation potentials (muscles firing random AP)
- fasciculations (muscle twitching)
basal ganglia
- interconnected group of grey matter structures in the brain
- scattered throughout sub-cortical and brainstem regions
- check motor activities
basal ganglia function
- filters out background activity in motor control
- so stops unwanted, jerky movements
1) takes info from cerebrum and checks it
2) amplifies or pos. reinforces movement
input areas of basal ganglia
- caudate nucleus
- lentiform nucleus (outside of putamen)
known together at the STRIATUM
cranial nerve I
olfactory nerves
- picks up smell
- contributes to sense of taste
cranial nerve II
optic nerve
- perception of vision
- receives impulses from photoreceptors in the eye
- goes through optic canal into cranial cavity
- lateral geniculate nucleus
- optic chiasm is where the 2 optic nerves join
cranial nerve III
oculomotor nerve
- somatic and visceral motor axons
- cavernous sinus
- superior and inferior branches
supply muscles of the eye…
- levator palpebrae superioris muscle
- superior rectus muscle
- inferior rectus muscle
- medial rectus muscle
- inferior oblique muscle
autonomic functions
- control pupil and lens
- ciliary muscles alter curvature of lens (vision focus)
cranial nerve IV
trochlear nerve
- innervates
- superior oblique muscle
- movements of eyeball - abduction, depression, internal rotation
cranial nerve V
trigeminal nerve
- senspry innervation to face, facial muscles, sinuses, mucosa
- muscles of musculation (chewing)
emerges from pons in motor and sensory routes
- both routes come together at trigeminal ganglion
- > has an extension of the dura called Meckel’s cave
what are the 3 main branches of the CNV
opthalmic
maxillary
mandibular
cranial nerve VII
facial nerve
- muscles of facial expresion
- taste sensation
- autonomic innervation of
- salivary and lacrimal glands
2 routes
- motor route (motor neurones)
- intermediate nerve (sensory and autonomic)
geniculate ganglion
cranial nerve VIII
vestibulocochlear nerve
- made up of vestibular(posterior trunk) and cochlear nerve (anterior trunk)
- purely sensory
vestibular
- from semicircular canals, utircle and saccule
- posture and balance
cochlear
- spirals
- from hair-like cells in cochlea
- hearing and isolation of sound
cranial nerve IX
glossopharyngeal
- sensory, motor, parasympathetic
sensory to…
- oropharynx, middle ear cavity, auditory tube, carotid body and sinus, post 1/3rd of tongue (and taste)
parasymp to…
- carotid gland
motor to
- stylopharyngeus muscle
swallowing and speech
jugular foramen
cranial nerve X
vagus nerve
- from medulla oblingata of brainstem to medullary olive
- jugular foramen
branches
- meningeal
- auricular
- pharyngeal
- superior laryngeal
recurrent laryngeal nerve
supplies
- diffuse innervation to thorax and abdomen
- parasymp. innew
- autonomic to heart through deep cardiac plexus and superficial cardiac plexus
what are the main nerves of the brachial plexus
- musculocutaneous
- median
- radial
- ulnar
what are the 3 main nerves of the lumbosacral plexus
- femoral
- obturator
- sciatic
what cranial nerves have parasympathetic innervation
3, 7, 9, 10
oculomotor, facial, glossopharyngeal, vagus
what are neurones called when they go in and out the sympathetic chain without synapsing
splanchnic nerves
how do sympathetic neurones get into the sympathetic chain
- pass into mixed spinal nerve
- go through white rami communicans (myelinated)
- synapse with post ganglionic neurone in symp. chain
- axon travels back through grey rami communicans (non-myelinated)
layers of the abdominal wall
- skin
- subcutaneous layer
- muscle layer (3 layers)
- neurovascular plane
- transversalis fascia
- extraperitoneal fat
- parietal peritoneum
what are the 3 muscle layers of the abdomen
- external oblique
- internal oblique
- transverse abdomins
these 3 layers fuse together into single longitudinal muscles on each side that insert into rectus sheath
external oblique
- from lower thoracic cage then pass downwards and medially to the rectus sheath
- free lower margin known at the inguinal ligament
what are the sheet like fibrous tendons in the abdomen called
aponeurosis
internal oblique
- fibre direction is upward and medially
- from rectus sheath to the thoracolumbar fascia
transverse abdominis
- fibres pass transversely
- insert via the rectus sheath to the thoracolumbar fascia
- intercostal nerves run in the neurovascular plane of this muscle
rectus abdominis
- arise from pubic bone
- insert into the thoracic cage
- fibres interrupted by tendinous intersections
what is the distribution of abdominal aponeurosis’s above and below the arcuate line
below arcuate line
- aponeurosis (tendons of the abdominal muscles) all pass anteriorly
- no posterior rectus sheath so no transverse abdominus fibres and the internal oblique fibres all pass anteriorly
above arcuate line
- posterior rectus present
- in ternal oblique splits into anterior and posterior layers and passes 50/50 infront an dbehind the radius bdominis
what spinal levels supply the neurovascular plane of the abdomin
T7-L1
`what are the longitudinal arteries of the abdomin
- superior epigastric artery (arising from the internal thoracic artery)
- inferior epigastric artery (arises from the external iliac artery)
functions of the abdominal wall
- moving the trunk
- protecting major body organs
- assists bodily functions
- assists breathing
whats the inguinal canal
- found in the medial part of the inguinal region which conveys the spermatic cord(male) and the round ligament of the uterus (females)
how does the inguinal canal form
- testis starts its life in abdominal wall
- it pushes through the abdominal wall creating a well
- as testis pulled out of the wall so is a part of the peritoneal cavity
- called PROCESSUS VAGINALIS
- so now testis is surrounded by a mini peritoneal cavity which is connected to the main peritoneal cavity by the processus
whats an indirect inguinal hernia
normally processus closes
- in some cases it persists or recanalizes
- creates a connection with the peritoneal cavity > sac of an indirect hernia
what forms the anterior and posterior walls of the inguinal canal
anterior wall
- formed by aponeurosis of external oblique and partly by internal oblique
- strong laterally but weak medially where it’s deficient at the superficial inguinal ring
posterior wall
- weak laterally where it’s deficient at the deep inguinal ring
- but strong medially where it’s formed by the conjoint tendon
inguinal shutter
if the internal oblique and transversus abdominus contract the inguinal canal will shut to reduce risk of herniation of abdominal contents along the inguinal canal
direct inguinal hernias
- the protrusion of a peritoneal sac through a weakened area of the abdominal wall ( with or without abdominal contents)
layers of the GI tract
mucosa
- epithelium
- lamina propria
- muscularis mucosae
submucosa
muscularis externa
adventitia/ serosa
mucosa
epithelium
- where most variation takes place
- S.I > vili
- L.I > stratified squamous
- glands
lamina propria
- connective tissue and vessels and nerves
muscularis mucosae
- inner circular layer and outer longitudinal layer
submucosa
- loose connective tissue
- contains blood vessels, nerves, lymphatic channels
- submucousal glands secrete mucous
- meissner plexus (nerve cells supplying muscularis mucosa and secretatory glands)
muscularis externa (propria)
smooth muscle
- inner - circular
- outer - longitudinal
coordination activity results in peristalsis
innervated parasympathetically mostly but also autonomically
adventitia and serosa
- outer layer of connective tissue - adventitia
- in some areas of GI tract there’s a second layer - serosa
- blood and lymph vessels
- serosa (covers inter-peritoneal organs, secretes serous fluid to lubricate)
what layer are lymphatics in the GI tract
submucosa
oesophagus histological features
mucosa
- stratified squamous epithelium
- proliferated basal layer (thats highly turned over)
submucosa
- large qualities of elastin fibres for expansion
- production of a mucus layer
muscularis externa
- upper 3rd - striated muscle
- mid - striated and smooth
- lower - smooth
adventitia
- serosa (simple squamous epithelium) forms outermost layer
stomach histology
mucosa
- simple columnar epithelium (really tall, one layer)
- gastric glands project into lamina propria (spaces between these projections = gastric pits)
- surface mucousal cells (thick protective later ontop of epithelium to prevent digestion of gastric wall)
lamina propria
- cell rich (fibroblasts, macrophages etc)
muscularis mucosa
- contracts to expel contents of the gastric pits into the lumen of the stomach
submucosa
- large blood vessels, nerve and lymphatic channels
- elastin for distention and movement
muscularis externa
- 3 muscular layers (innermost oblique, middle circular, external longitudinal)
adventitia
- visceral peritoneum
gastric glands cells
- stem cells in the neck
- neck mucus cells
- parietal cells
- peptic/ chief cells
- neuroendocrine cells
what are the 3 types of projections in the small intestines
- plicae circulares (folds of the mucosa)
- villi (project out of the plicae circulares)
- columnar epithelial cells (project out the villi)
all to inc. SA of s. intestine
histology of the small intestines (mucosa)
- projections^
- goblet cells
- simple columnar epithelium
- lacteals and capillaries
- crypts of lieberkuhn
- > between villi
- > open into the lumen at the base of the villi
- > contain stem cells, absorptive cells, etc
- lymphatic deposits
- > connected to lacteal networks
- > monitor intestinal bacteria (prevent overgrowth of pathogens)
histology of the small intestines (submucosa, muscularis externa, serosa)
submucosa - many vessels and lymphoid aggregations - main blood supply to the mucosa - Brunner's glands - duodenum -> produces alkaline secretions to neutralise stomach chyme Peyer's patches - ileum -> large congregation of lymphoid tissue -> monitor intestinal bacteria
muscularis externa
- 2 layers of smooth muscle
- peristalsis
serosa
- produces serous fluid to allow intestines to move over each other
large intestine histology (mucosa)
- smooth thick mucosa
- deep crypts
- no villi
epithelium
- columnar mucous absorptive cells
- goblet cells
- basal cells (turnover quickly - 6days)
lamina propria
- collagen dense
- regulates water and electrolyte balance (from absorptive cells into blood circulation)
large intestine histology (submucosa, muscularis externa, serosa)
submucosa
- similar to s. intestine
- large aggregates of lymphoid tissue
muscularis externa
- inner circular layer of smooth muscle
- outer longitudinal is condensed into 3 bands (taeniae coli)
- myenteric plexus between muscle layers
adventitia
- outer serosal layer - intraperitoneal
- serosa doesn’t go all the way arounf the tube of the L.I
- this part of the LI that doesn’t have a serosa layer is where it’s continous with the abdominal wall/ mesentery (only adventitia here)
what is peritoneum and what are the types
peritoneum is mesothelium tissue, it’s a supportive layer of connective tissue
parietal peritoneum - lines abdominal wall
visceral peritoneum - covers abdominal/ pelvic organs
what are the folds of the peritoneum called
mesentery
intraperitoneal organs
- organs invested in the peritoneum
- 1st part of duodenum, spleen, liver, jejunum, ileum, transverse colon, sigmoid colon, superior rectum
retroperitoneal organs
- organs behind peritoneal cavity
- covered by parietal peritoneum anteriorly
- end of duodenum, kidneys, ureters, ascending and descending colon
- viscera not actually in the peritoneum they are pushed in like pushing your finger into a balloon
omentum
- another form of peritoneum
- double layered fold of peritoneum
- sim. to mesentery
2 parts
- greater and lesser omentum
mesentery
connects jejunum and ileum to posterior abdominal wall
- allows movement for digestion, breathing etc
greater omentum
- 4 layers
- “policeman of the abdomen”
- move to areas that are inflamed and wrap around structure to protect from inflammation
- attached to greater curvature of stomach and first part of duodenum -> transverse colon
- moves via peristalsis
- made up of fat, connective tissue, lymphatics
- also bad bc allows for spread of cancer due to lymphatics in it
lesser omentum
- 2 layers
- lesser curvature of stomach and 1st part of duodenum -> inferior surface of liver
peritoneal cavity
the potential area between the parietal and visceral peritoneum
has a thin layer of peritoneal fluid
- enables viscera to move against each other during resp and digestion
- fluid formed form water, electrolytes and other
- contains leukocytes and antibodies that resist infection
what are the 2 sacs in the peritoneum
greater sac
- largest part
- diaphragm -> pelvic cavity
lesser sac/ omental bursa
- post. to liver and stomach
- omental/ epiploic foramen
- bounded anteriorly by lesser omentum
- cont. with greater sac via epiploic foramen/ omental foramen
epiploic foramen
- communication between greater and lesser sacs
- opening located posteriorly to free edge of the lesser omentum
how to locate the epiploic foramen
- locate gall bladder
- run finger along the gall bladder to find free edge of lesser omentum
- foramen usually 2 fingers in width
- behind portal triad
what ligament connects the liver to the anterior abdominal wall
faliciform ligament
what ligament connects the liver to the stomach
hepatogastric ligament
- membranous portion of the lesser omentum
- continous with lesser omentum
what ligament connects the liver to the duodenum
hepatoduodenal ligament
- free edge of lesser omentum
- contains the portal triad
- continous with part of lesser omentum
what ligaments connect the stomach…
gastrophrenic ligament
- connects stomach to inferior surface of diaphragm
gastrosplenic ligament
- connects stomach to spleen
gastrocolic ligament
- connects stomach to the transverse colon
- part of the greater omentum
peritoneal spaces
=potential spaces within the peritoneal cavity
supracolic compartment
- stomach, liver, spleen
infracolic compartment
- s. intestine, asc. and desc. colon, behind greater omentum, r. and l. infracolic spaces
paracolic gutters
- depressions between ascending and descending colon and posterolateral abdominal wall
- passage between supracolic and infracolic compartments
why are paracolic gutters clinically important
- allow for communication between supra and infra colic compartments
- passageway for infections/ cancer to spread
hepatorenal recess
- between liver and R. kidney and suprarenal gland
- also known as morrisons pouch
- continuous witht he right subphrenic recess anteriorly
peritoneal spaces in the pelvic cavity
rectouterine pouch
- pouch of douglas
- only in females
- peritoneum fold between the rectum and the uterus
vesico-uterine pouch
- between bladder and uterus
rectovesical pouch
- between bladder and rectum
- males only
functions of peritoneal spaces
- contains peritoneal fluid to lubricate adjacent peritoneal membrane
- create more room for viscera
- reducing congestion of structures
- sites for catheter insertion
subphrenic recess
- subphrenic abscesses may form in here
- accumulation of pus in L or R subphrenic space
most common in right due to…
- appendicitis
- ruptured duodenal ulcer
- pus from appendix to subphrenic recess via R paracolic gutter
what are the oesophageal constrictions
- boundary between pharynx and oesophagus (C6)
- aorta
- left main bronchi
- diaphragm
what are the 4 regions of the stomach
- cardia
- fundus
- body
- pyloric part (antrum, canal)
curvatures of the stomach
lesser curvature
- attached to lesser omentum
gretaer curvature
- attached to greater omentum and gastrosplenic ligament
what are the longitudinal folds that allow the stomach to expand called
gastric rugae
duodenum
4 parts
- superior
- descending
- inferior
- ascending
what are the duodenal papilla
minor
- for accessory pancreatic duct
major
- for main ducts for pancreas and bile ducts emptying into duodenum for digestion
jejenum
- thicker and larger in diameter than ileum
- longer vasa recta
- numerous folds of inner lining PLICAE CIRCULARES
variation of arterial arcades throughout the intestines
- in proximal s. intestine longer and fewer
- in distal s. intestine numerous and shorter
ileum
- mostly in the lower r. quadrant
- thiner walls and less prominent plicae circulares
- shorter vasa recta
- more mesenteric fat
- contents move faster
cecum
- located in the right iliac fossa (lower right quadrant) - inferior to ileocecal opening - continous with ascending colon - attached to posteromedial wall of cecum
appendix
- narrow, hollow, blind ended tube attached to base of cecum
- aggregation of lymphoid tissue in walls
- base is continous with end of taeniae coli
- pos. of rest of appendix if=s highly variable
how to locate the appendix
- McBurney’s Point
- found between umbilicus and anterior-superior iliac spine
- divide into 3
- > in middle third and lateral third = base of appendix
hows the colon different form the small intestine
- larger in diameter
- omental appendices (fat tags)
- taeniae coli
- sacculation’s (haustra of the colon)
ascending colon
- retroperitoneal
- connects cecum to transverse colon
- ascends as high as right lobe of the liver before rotating 90 degreed (right colic flexure)
transverse colon
- links left and right colic flexures
- midgut-hingut boundary = 2/3rds of the way along transverse colon
- suspended in transverse mesocolon
descending colon
- retroperitoneal
- connects left colic flexure to sigmoid colon
sigmoid colon
- s-shaped
- suspended by sigmoid mesocolon
- located in left lower quadrant
- runs from above pelvic inlet to S3
- continuous with rectum
rectum
- starts at rectosigmoid junction
- lacks features of typical l. intestine
retroperitoneal - 3 lateral flexures (superior, middle, inferior)
- ampulla accomodates contents just before they’re expelled
what level is the coeliac trunk
T12
the liver coverings
- intraperitoneal
- covered by visceral peritoneum
- except bare area, gallbladder fossa and porta hepatis
what are the 4 lobes of the liver
- right
- left
- caudate
- quadrate
