Session 3 - major blood vessels and lymphatics Flashcards
which vein drains the head
internal jugular
which vein drains the neck
external jugular
what arteries branch of the subclavian artery at the base of the neck
vertebral, internal thoracic, and thyrocervical
what are the branches of the thyrocervical trunk and what do they supply
ascending cervical and transverse cervical supply the neck
suprascapular supplies the shoulder
inferior thyroid supplies the lower pole of the thyroid gland
which arteries supply the brain
vertebral arteries
internal craotid
what is the path of the vertebral arteries
the arise from the subclavian arteries and ascend in the neck through the foramina in cervical vertebrae 6-1 and pass through the foramen magnum
through which structure does the internal carotid artery enter the skull
the carotid canal
what is the location at which the common carotid artery bifurcates
C4
at about the level of the superior border of the thyroid cartilage
what is a common site for atheroma formation and why
what does this lead to
the bifurcation of thee carotid artery
this is because of turbulence at the bifurcation
if the clot ruptures it can cause an embolus to travel to the brain causing a TIA or stroke
what is the location of the baroreceptors
carotid sinus - at the bifurcation
what is the location of the chemoreceptors and what do they detect
carotid body
detect arterial oxygen
where can you feel the carotid pulse
in the carotid triangle just below the bifurcation
when would you give a patient a carotid sinus message
given to someone with a supraventricular tachycardia
as this will make the barorecptors stretch and emulate high BP so vagus imput will increase to try to decrease the heart rate
what is the route of the internal carotid artery
enters the skull through the carotid canal in the petrous part of the temporal bone
turns medially and horizontally
enters the cranial cavity then makes S shaped bend
courses through the cavernous sinus
what are the contents of the cavernous sinus
plexus of extremely thin walled veins on the upper surface of the sphenoid
internal carotid artery
CNIII oculomotor
CNIV trochlear
CNVI abducent
2 branches of trigeminal- CNV1 opthalmic and CNV2 maxillary
name three branches of the opthalmic artery
supratrochlear
supraorbital
central retinal
what artery does the opthalmic artery branch from
internal carotid artery
what are the six branches of the external carotid artery
and the two terminal branches
superior thyroid lingual facial ascending pharyngeal occipital posterior auricular
superficial temporal
maxillary
what is the blood supply to the scalp
from the internal carotid- supra orbital artery and supra trochlear arterty
from the external carotid artery- superficial temporal, posterior auricular and occipital artery
rich blood supply with many anastamoses
what are the layers of the SCALP
Skin Connective tissue dense Aponeurosis Loose connective tissue Periosteum
in which layer do the vessels of the scalp lie
they lie in the subcutaneous dense connective tissue layer
why can you get profuse bleeding of the scalp
the walls of the arteries are closely attached to connective tissue, this limits the ability of the vessels to constrict
and deep laceration involving the aponeurosis can cause profuse bleeding because of the opposing pull of occipitofrontalis
why is the blood supply to the skull not compromised in scalp injury
the blood supply to the skull is mostly via the middle meningeal artery- so loos of the scalp does not lead to bone necrosis
what are the superficial arteries supplying the face
supra orbital supratrochlear transverse facial angular lateral nasal maxillary superior and inferior labial facial
where can you feel the facial artery pulse
inferior border of the mandible, anterior to the masseter muscle
what is the blood supply to the nasal septum
septal branch sphenopalatine artery (branch of the maxillary)
anterior ethmoidal arteries- (branch of opthalmic artery)
anastamoses of arteries in the kiesselbach area
what is a common site of epistaxis
kiesselbach area
what is the blood supply to the dura and the skull
middle meningeal artery
what structure of the skull does the middle meningeal artery travel through
foramen spinosum
what type of haemorrhage do you get if you fracture the skull at the pterion
and which artery ruptures
extradural haemorrhage
middle meningeal artery ruptures
what is a craniotomy
when a flap of bone and scalp is reflected inferiorly to preserve blood supply
craniotomy gives access to cranial cavity
what is the venous drainage of the scalp
superficial veins- superficial temporal, occipital, posterior auricular, posterior auricular veins
supraorbital and supratrochlear veins unite at medial angle of eye to form angular vein which drains into the facial vein
how are the veins in scalp connected to the veins in the skull
veins of the scalp connect to diploic veins of skull through several emissary veins and thus to dural venous sinuses
why does infection from the scalp spread easily to the cranial cavity and affect meinges
the emissary veins connecting the scalp and skull are valveless
which veins drain the face
supraorbital supratrochlear angular superior and inferior labial veins facial common facial external jugular internal jugular
why can infection spread from facial vein to dural venous sinuses
the facial vein communicates with the superior opthalmic vein at the medial angle of eye
they both drain into the cavernous sinus
deep facial veins drain into pterygoid venous plexus- and infection can spread from facial vein to dural venous sinuses
the veins of the face are valveless
where can a thrombophlebitis of the facial vein end up
intracranial venous system
so a infected clot can travel this way
what structure do the internal jugular veins exit through
jugular foramina
what vessel can be used to measure jugular venous pressure
right internal jugular vein is the best indicator of pressure in the right atrium but the external jugular vein is much easier to see as the internal jugular vein is behind the SCM
describe the formation of tissue fluid
net filtration of fluid is not equal to the net reabsorbtion of fluid
not all the fluid that was filtered out of the capillaries at the arteriole end is reabsorbed by the capillaries and the venule end
this is because some of the small proteins that move out of the capillary bed and into the interstital fluid do not get reabsorbed
this means some water remains with these proteins due to the oncotic pressure exerted by the small proteins in the intestitial fluid
describe the formation of lymph fluid
lymphatic capillary walls are much more porous so it is easier for small proteins and hence water to move into the lymphatic vessels at the venous end
this is eventually returned back into venous circulation
what are the contents of lymph fluid
tissue fluid small proteins damaged cells bacteria lipids cancer cells
how much lymph does the body produce a day
3-4L
what is the purpose of lymphatic vessels
to continuously remove the remaining tissue fluid in the extracelluar space via series of lymph nodes back into the circulation
what are the main features of the lymph system
uni directional flow
low pressure system
no central pump
why is the lymphatic system under low pressure
there are multiple entry points but only one exit point so this will slow the lymph down
this gives time for the lymph nodes to clean the lymph
needs to be under low pressure so the lymphatics can can move into the low pressure venous system
pressure of lymphatic system only need to be slightly higher than that of the venous system
describe the drainage of lymph from the tissue fluid to the venous system
tissue fluid - lymphatic capillary - lymphatic vessels - lymph node - lymphatic vessels - lymph node - lymphatic vessels - lymphatic trunks (right and left) - drain into the right lymphatic duct and left thoracic trunk
what aids in the flow of lymph
passive constriction -the run in line with blood vessels so the pulsation from the vessels will help move the blood along
intrinsic constriction- the lymphatic vessels automatically constrict when they start to feel themselves fill up
why does lymph only go in one direction
valves which prevent lymph going in wrong direction
which vein does the thoracic duct drain into
left subclavian vein
which vein does the right lymphatic duct drain into
right subclavian vein
which duct drains most of the body
thoracic duct
what parts of the body does the right lymphatic duct drain
half of the head and thorax and the right upper limB
what is lymphodema
it is the collection of protein rich fluid causing tissue swelling due to compromised lymphatic swelling
why does lymphodema occur
removal or enlargement of lymph nodes
infections (parasites)- elephantitis
damage to lymphatic system e.g. in cancer treatment
lack of limp movement ( movement of lymph fluid not aided by muscle contraction)
congenital e.g. Milory’s syndrome
describe the structure of a lymph node
tough fibrous outer capsule
reticular connective tissue inside
contains B and T lymphocytes and macrophages
who do lymph nodes swell and cause pain in infection
when infection is present the number of B cells increases so the lymph nodes swell
can only stretch so much because of the tough fibrous outer capsule
as it cannot stretch past this we get pain
how do lymph nodes defend against infection
physical filter
phagocytic filter
full of lymphocytes which activate and proliferate in response to antigens
how can you tell the difference between an infected lymph mode and a malignancy
infected lymph nodes are tender and mobile
in malignancy they are hard, matted and non-tender
what is the difference between a regional and terminal node
a regional node drains a specific area and them drains into a terminal node
a terminal node receives drainage from multiple regional nodes
regional nodes are superficial
terminal nodes are deep
where in the body are collection of lymph nodes most palpable
in the neck and armpit
what separates superficial regional and deep terminal lymph nodes
separated by investing layer of deep cervical fascia in the neck
what is waldeyer’s ring
it is an annular collection of lumphatic tissue (nodules) that surround the entrance to the aerodigestive tracts
completely encircle the upper pharynx
what does waldeyer’s ring consist of
pharyngeal tonsil (adenoids)
tubal tonsils
palatine tonsils
lingual tonsils
where do lymphatics from tonsils draining the upper pharynx drain into
retro-pharyngeal lymph nodes
what could enlarged supraclavicular nodes be a sign of
and why
Abdominal malignancy
supraclavicular lymph nodes oversee the transport of lymph from thoracic cavity to abdomen
left node - abdomen and thorax
right node- mid section chest, oesophagus and lungs
which lymph nodes are most commonly enlarged in viral conjunctivitis
pre-auricular
which lymph nodes are most commonly enlarged in an ulcer of the lip
submental
which lymph nodes are most commonly enlarged in tonsillitis
jugulo-digastiric
which lymph nodes are most commonly enlarged in tongue cancer
submandibular and deep cervical
what are deep cervical lymph nodes found in close relation to
and what muscle do they run deep to
the IJV within the carotid sheath
they run deep to SCM
