Innervation and blood supply Flashcards
What is the blood supply to the skin?
- Subpapillary plexus - upper epidermis, supplies upper appendages (e.g. erector pili muscles)
- Cutaneous plexus - on the hypodermis/dermis junction
- Arteriovenous shunts - blood vessel connections controlled by glomus bodies that are used to divert the blood away from the surface when it is cold
What are the nerve endings in the skin and their locations?
- Merkel cells -> Epidermal basal layer -> Touch
- Free nerve endings -> Dermis -> Pain, itch and temperature
- Meissner’s corpuscles -> Dermis -> Light touch
- Pacinian corpusclees -> Deep in dermis -> Coarse touch, vibration and tension
What innervation does brown adipose tissue receive?
Sympathetic
Where are the blood vessels found within bone?
In compact bone, blood vesseks and nerves are found running within Haversian canals.
Which ganglia supplies the foregut and what nerve feeds into it?
Coeliac ganglia (prevertebral, sympathetic), supplied by the greater splanchnic nerve.
Which ganglia supplies the midgut and what nerve feeds into it?
Superior mesenteric ganglia (prevertebral, sympathetic), supplied by the lesser splanchnic nerve.
Which ganglia supplies the hindgut/pelvic organs and what nerve feeds into it?
The inferior mesenteric ganglia (prevertebral, sympathetic), supplied by the least splanchnic nerve.
What nerve fibres modulate the enteric system?
- Pre-ganglionic parasympathetic:
- Vagus nerve
- Sacral fibres
- Post-ganglionic sympathetic:
- From prevertebral ganglia
What are the four cranial nerves we need to know for first year (and their numbers)?
- III - Oculomotor
- VII - Facial
- IX - Glossopharyngeal
- X - Vagus
Which cranial nerve is the oculomotor and what does it supply?
- III
- Supplies the iris of the eye (via the ciliary ganglion)
Which cranial nerve is the facial nerve and what does it supply?
- VII
- Supplies the lacrimal glands and nasal mucosa (via the pterygopalatine ganglion)
- Supplies the salviary glands (via the submandibular ganglion)
Which cranial nerve is the glossopharyngeal nerve and what does it supply?
- IX
- Supplies the parotid salivary gland (via the otic ganglion)
Which cranial nerve is the vagus and what does it supply?
- X
- Supplies the organs of the thorax and abdomen
Which nerve innervates the adrenal gland?
Greater splanchnic
What do the paravertebral ganglia supply? (Sympathetic chain)
- Two paravertebral ganglia run either side of the spine
- These supply multiple organs
- Cervical ganglia lie at the top of the paravertebral chains
- These supply the head (superior cervical ganglion) and thorax (heart + lungs, middle cervical and stellate ganglia)
What do the sacral parasympathetic fibres supply?
- Meissner’s plexus (submucosal)
- Auerbach’s plexus (myenteric)
- Lower gut
- Urogenital tract
What provides blood supply to the humeral head?
- Anterior circumflex humeral artery
- Posterior circumflex humeral artery
What do posterior and anterior rami innervate/supply?
- Posterior: Spinal extensors and overlying skin
- Anterior: Limbs and ventral trunk
What are the nerves that supply the flexor and extensor compartments of the upper limb? Include their nerve roots.
- Flexor: Musculocutaneous (C5-C7)
- Extensor: Radial (C5-T1)
What are the nerves that supply the flexor and extensor compartments of the lower limb? Include nerve roots.
- Flexor: Sciatic (L4-S3)
- Extensor: Femoral (L2-L4)
Which nerve passes posteriorly to the medial epicondyle of the humerus?
Ulnar nerve - very superficial, therefore easily knocked which stimulates a tingling sensation
What is innervated by the axillary nerve?
Deltoid and teres minor (amongst others)
What nerve innervates each of the rotator cuff muscles?
- Teres minor - axillary nerve
- Subscapularis - subscapular nerve
- Supraspinatus - suprascapular nerve
- Infraspinatus - suprascapular nerve
What nerve roots control shoulder abduction and adduction?
- Abduction: C5
- Adduction: C6, C7, C8
What nerve roots control shoulder flexion and extension?
- Flexion: C5
- Extension: C6, C7 ,C8
What nerve roots control elbow flexion and extension?
- Flexion: C5, C6
- Extension: C6, C7, C8
What nerve roots control forearm pronation and supination?
- Pronation: C7, C8
- Supination: C6
What nerve roots control wrist flexion and extension?
- Flexion:C6, C7
- Extension: C6, C7
What nerve roots control finger flexion, extension, abduction and adduction?
- Flexion: C7, C8
- Extension: C7, C8
- Abduction: T1
- Adduction: T1
What nerve roots control hip flexion and extension?
- Flexion:L2, L3
- Extension: L4, L5
What nerve roots control hip abduction and adduction?
- Abduction: L5, S1
- Adduction: L2, L3
What nerve roots control medial and lateral hip rotation?
- Medial: L2, L3
- Lateral: L5, S1
What nerve roots control knee flexion and extension?
- Flexion: L5, S1
- Extension: L3, L4
What nerve roots control plantarflexion and dorsiflexion?
- Plantarflexion: S1, S2
- Dorsiflexion: L4, L5
What nerve root controls foot inversion and eversion?
- Inversion: L4, L5
- Eversion: L5, S1
What nerve roots make up the brachial plexus?
C5-T1
What nerve roots make up the lumbosacral plexus?
L1-S3
Draw the sensory territories for the nerves of the upper limb.
Draw a diagram to show what the musculocutaneous nerve innervates.
Draw a diagram to show what the median nerve innervates.
Draw a diagram to show what the ulnar nerve innervates.
Draw a diagram to show what the radial nerve innvervates.
Draw a diagram to show what the femoral and obturator nerves innervate.
Draw a diagram to show what the sciatic nerve innervates.
Draw a diagram to show what the tibial nerve innervates.
Draw a diagram to show what the fibular nerves innervate.
Draw the sensory territories for the lower limb.
What is the ductus arteriosus?
- Blood vessel in developing foetus that connects the aorta to the left ventricle.
- Allows the blood to bypass the developing lungs which are still full of fluid.
- Closure occurs after birth, resulting in the formation of the ligamentum arteriosum.
What supplies blood to the heart?
Coronary arteries
What are the different coronary arteries?
- Right coronary artery and left coronary artery form a ring around the atrioventricular groove, forming an incomplete arterial ring. Branches from this reach down to the apex.
- Left coronary artery
- Left anterior descending artery -> lies between the ventricles on the anterior side.
- Left circumflex artery and left marginal artery -> supply the left side of the heart.
- Posterior descending artery -> variable anatomy, usually supplied by the right coronary artery.
- Right coronary artery
- Right marginal artery -> supplies the right side of the heart.
- Posterior descending artery -> variable anatomy, but this is the more common variation.
What is the arterial blood supply of the head?
- Each common carotid artery splits (at the coronary sinus) into:
- Internal carotid artery -> supplies brain, eyes and forehead through the carotid canal of the skull.
- External carotid artery -> supplies areas of head and neck that are exterior to the cranium.
- Gives off 6 branches: superior thyroid, linguinal, facial, ascending pharyngeal, occipital and posterior auricular arteries.
- Each subclavian artery gives off a vertebral artery that converge and supply the brain.
What is the venous drainage for the heart?
Coronary sinus (drains back into the right atrium).
Some venae cordis minimae (smallest cardiac veins) drain directly into the right atrium rather than entering the chamber through the coronary sinus.
Describe the arterial supply to the upper limb.
Describe the arterial supply to the lower limb.
Describe the venous drainage of the lower limb.
Superficial veins:
- Great saphenous vein
- Drains blood from the dorsal arch of the foot, running along the medial side of the leg.
- Passes anterior to the medial malleolus but posterior to the medial condyle at the knee.
- Drains into the femoral vein just inferior to the inguinal ligament.
- Small saphenous vein
- Drains blood from the dorsal arch of the foot and from the dorsal vein of the little toe.
- Runs along the posterior side of the leg, passing posterior to the lateral malleolus and along the calcaneal tendon, passing between the two heads of gastrocnemius.
- Empties into the popliteal vein at the popliteal fossa.
Deep veins - RUN ALONG ARTERIES
- Posterior tibial and fibial vein -> these arise from the lateral and medial plantar veins.
- Popliteal vein
- Anterior tibial vein
- Femoral vein
- Profunda femoris
- External iliac vein
Communicating veins drain via the superficial into the deep veins.
What is the venous supply of the head?
- Internal jugular veins -> drain the brain and parts of the face, drain INTO the subclavian veins to form the brachiocephalic veins.
- External jugular veins -> drain the superficial tissues of the skull and the posterior and deep parts of the face, draining into the subclavian veins before they join with the internal jugulars.
- Anterior jugular veins -> drain the neck, draining into the external jugular veins just before they drain into the subclavian.
What vessel supplies oxygenated blood to the dorsal surface of the foot?
Dorsalis pedis
What vessels supply oxygenated blood to the walls of large veins and arteries?
Vasa vasorum (‘vessels of vessels’)
What is the organisation of the major vessels in the thorax?
Thoracic aorta:
- Ascending aorta gives off the right and left coronary arteries which go to the heart.
- Aortic arch gives off:
- The brachiocephalic artery, which in turn gives rise to the right subclavian (supplies the upper limb, neck and thorax) and right common carotid arteries.
- Left common carotid artery
- Left subclavian artery
- Subclavian arteries each give off a thoracic artery that gives off anterior inctercostal arteries. They also give off the vertebral arteries, the major arteries of the neck.
- Descending aorta gives off:
- Bronchial arteries
- Oesophageal arteries
- Posterior intercostal arteries (go to body wall, where they anastamose with the anterior intercostal arteries).
What is the organisation of the major vessels in the abdomen?
Abdominal aorta gives rise to: (in descending order)
- Inferior phrenic arteries (paired, may arise directly above the coeliac artery or even from it), supply the diaphragm.
- Coeliac artery (midline, unpaired), arises at ~T12 and supplies the foregut (oesophagus to mid-duodenum)
- Adrenal/suprarenal arteries (paired), supply the adrenal glands.
- Superior mesenteric artery (midline, unpaired), arises at ~L1 and supplies the midgut (mid-duodenum to the colon splenic flexure).
- Renal arteries (paired), arise at ~L1, supply the kidneys.
- Paired lumbar arteries (series), supplying the posterior abdominal wall.
- Gonadal arteries (paired), arise at ~L2, supply the gonads.
- Inferior mesenteric artery (midline, unpaired), arises at ~L3, supplies the hindgut (splenic flexure to the recto-anal junction).
At the level of L4, the aorta bifurcates into the common iliac arteries, which then give rise to:
- External iliac arteries (supply lower limbs via the femoral artery).
- Internal iliac arteries (supply the pelvic organs and gluteal region).
What major vessel supplies the head?
Common carotid, which bifurcates into the external and internal carotid arteries. (On the RHS, this originates from the brachiocephalic artery).
What major vessel supplies the upper limb and part of the thorax and neck?
The subclavian artery. (On the RHS, this originates from the brachiocephalic artery).
What major vessel supplies the foregut?
Coeliac artery (T12)
What major vessel supplies the midgut?
Superior mesenteric artery (L1)
What major vessel supplies the hindgut?
Inferior mesenteric artery (L3)
Which artery supplies the gonads?
Gonadal arteries (paired, L2)
Which artery supplies the kidneys?
Renal arteries (L1)
What major vessel supplies the lower limb and pelvis?
Common iliac arteries (bifurcates to form the internal and external iliac arteries which supply the pelvic organs and lower limb (via the femoral artery) respectively).
What artery supplies most of the thigh with oxygenated blood?
Deep femoral artery (profunda femoris)
Describe the aortic supply of the thoracic cage.
- Each subclavian artery gives off internal thoracic arteries that run down the anterior side of the thorax.
- The internal thoracic arteries give off the anterior intercostal arteries.
- The descending aorta gives off the posterior intercostal arteries.
What arteries supply the lungs?
- Pulmonary arteries -> Supply exchange parts of the lungs
- Bronchial arteries -> Supply non-exchange parts of the lungs (e.g. bronchi)