Innervation and blood supply Flashcards
(180 cards)
1
Q
What is the blood supply to the skin?
A
- 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
2
Q
What are the nerve endings in the skin and their locations?
A
- 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
3
Q
What innervation does brown adipose tissue receive?
A
Sympathetic
4
Q
Where are the blood vessels found within bone?
A
In compact bone, blood vesseks and nerves are found running within Haversian canals.
5
Q
Which ganglia supplies the foregut and what nerve feeds into it?
A
Coeliac ganglia (prevertebral, sympathetic), supplied by the greater splanchnic nerve.
6
Q
Which ganglia supplies the midgut and what nerve feeds into it?
A
Superior mesenteric ganglia (prevertebral, sympathetic), supplied by the lesser splanchnic nerve.
7
Q
Which ganglia supplies the hindgut/pelvic organs and what nerve feeds into it?
A
The inferior mesenteric ganglia (prevertebral, sympathetic), supplied by the least splanchnic nerve.
8
Q
What nerve fibres modulate the enteric system?
A
- Pre-ganglionic parasympathetic:
- Vagus nerve
- Sacral fibres
- Post-ganglionic sympathetic:
- From prevertebral ganglia
9
Q
What are the four cranial nerves we need to know for first year (and their numbers)?
A
- III - Oculomotor
- VII - Facial
- IX - Glossopharyngeal
- X - Vagus
10
Q
Which cranial nerve is the oculomotor and what does it supply?
A
- III
- Supplies the iris of the eye (via the ciliary ganglion)
11
Q
Which cranial nerve is the facial nerve and what does it supply?
A
- VII
- Supplies the lacrimal glands and nasal mucosa (via the pterygopalatine ganglion)
- Supplies the salviary glands (via the submandibular ganglion)
12
Q
Which cranial nerve is the glossopharyngeal nerve and what does it supply?
A
- IX
- Supplies the parotid salivary gland (via the otic ganglion)
13
Q
Which cranial nerve is the vagus and what does it supply?
A
- X
- Supplies the organs of the thorax and abdomen
14
Q
Which nerve innervates the adrenal gland?
A
Greater splanchnic
15
Q
What do the paravertebral ganglia supply? (Sympathetic chain)
A
- 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)
16
Q
What do the sacral parasympathetic fibres supply?
A
- Meissner’s plexus (submucosal)
- Auerbach’s plexus (myenteric)
- Lower gut
- Urogenital tract
17
Q
What provides blood supply to the humeral head?
A
- Anterior circumflex humeral artery
- Posterior circumflex humeral artery
18
Q
What do posterior and anterior rami innervate/supply?
A
- Posterior: Spinal extensors and overlying skin
- Anterior: Limbs and ventral trunk
19
Q
What are the nerves that supply the flexor and extensor compartments of the upper limb? Include their nerve roots.
A
- Flexor: Musculocutaneous (C5-C7)
- Extensor: Radial (C5-T1)
20
Q
What are the nerves that supply the flexor and extensor compartments of the lower limb? Include nerve roots.
A
- Flexor: Sciatic (L4-S3)
- Extensor: Femoral (L2-L4)
21
Q
Which nerve passes posteriorly to the medial epicondyle of the humerus?
A
Ulnar nerve - very superficial, therefore easily knocked which stimulates a tingling sensation
22
Q
What is innervated by the axillary nerve?
A
Deltoid and teres minor (amongst others)
23
Q
What nerve innervates each of the rotator cuff muscles?
A
- Teres minor - axillary nerve
- Subscapularis - subscapular nerve
- Supraspinatus - suprascapular nerve
- Infraspinatus - suprascapular nerve
24
Q
What nerve roots control shoulder abduction and adduction?
A
- Abduction: C5
- Adduction: C6, C7, C8
25
What nerve roots control shoulder flexion and extension?
* Flexion: C5
* Extension: C6, C7 ,C8
26
What nerve roots control elbow flexion and extension?
* Flexion: C5, C6
* Extension: C6, C7, C8
27
What nerve roots control forearm pronation and supination?
* Pronation: C7, C8
* Supination: C6
28
What nerve roots control wrist flexion and extension?
* Flexion:C6, C7
* Extension: C6, C7
29
What nerve roots control finger flexion, extension, abduction and adduction?
* Flexion: C7, C8
* Extension: C7, C8
* Abduction: T1
* Adduction: T1
30
What nerve roots control hip flexion and extension?
* Flexion:L2, L3
* Extension: L4, L5
31
What nerve roots control hip abduction and adduction?
* Abduction: L5, S1
* Adduction: L2, L3
32
What nerve roots control medial and lateral hip rotation?
* Medial: L2, L3
* Lateral: L5, S1
33
What nerve roots control knee flexion and extension?
* Flexion: L5, S1
* Extension: L3, L4
34
What nerve roots control plantarflexion and dorsiflexion?
* Plantarflexion: S1, S2
* Dorsiflexion: L4, L5
35
What nerve root controls foot inversion and eversion?
* Inversion: L4, L5
* Eversion: L5, S1
36
What nerve roots make up the brachial plexus?
C5-T1
37
What nerve roots make up the lumbosacral plexus?
L1-S3
38
Draw the sensory territories for the nerves of the upper limb.
39
Draw a diagram to show what the musculocutaneous nerve innervates.
40
Draw a diagram to show what the median nerve innervates.
41
Draw a diagram to show what the ulnar nerve innervates.
42
Draw a diagram to show what the radial nerve innvervates.
43
Draw a diagram to show what the femoral and obturator nerves innervate.
44
Draw a diagram to show what the sciatic nerve innervates.
45
Draw a diagram to show what the tibial nerve innervates.
46
Draw a diagram to show what the fibular nerves innervate.
47
Draw the sensory territories for the lower limb.
48
49
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.
50
What supplies blood to the heart?
Coronary arteries
51
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.
52
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.
53
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.
54
Describe the arterial supply to the upper limb.
55
Describe the arterial supply to the lower limb.
56
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.
57
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.
58
What vessel supplies oxygenated blood to the dorsal surface of the foot?
Dorsalis pedis
59
What vessels supply oxygenated blood to the walls of large veins and arteries?
Vasa vasorum ('vessels of vessels')
60
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).
61
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).
62
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).
63
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).
64
What major vessel supplies the foregut?
Coeliac artery (T12)
65
What major vessel supplies the midgut?
Superior mesenteric artery (L1)
66
What major vessel supplies the hindgut?
Inferior mesenteric artery (L3)
67
Which artery supplies the gonads?
Gonadal arteries (paired, L2)
68
Which artery supplies the kidneys?
Renal arteries (L1)
69
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).
70
What artery supplies most of the thigh with oxygenated blood?
Deep femoral artery (profunda femoris)
71
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.**
72
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)
73
What arteries supply the nasal mucosa?
Originating from the internal and external carotid supply:
* Maxillary artery
* Facial artery
* Branches of the ophthalmic artery
74
Describe the nerves that innervate the nasal passage.
* Olfactory Nerve (I) -\> Smell
* Trigeminal Nerve (V) -\> General sensory
* Facial Nerve (VII) -\> Parasympathetic supply (of mucosa)
75
What nerve innervates the trachea?
Pulmonary plexus:
* Recurrent laryngeal nerves (branches of the vagus) -\> Parasympathetic supply
* Sympathetic trunks -\> Sympathetic supply
76
What nerves innervate the larynx?
Branches of the vagus nerve:
* Recurrent laryngeal nerve -\> Sensory innervation of the infraglottis, and motor innervation to all the internal muscles of larynx (except the cricothyroid).
* Superior laryngeal nerve -\> Internal branch provides sensory innervation to the supraglottis, and external branch provides motor innervation to the cricothyroid muscle.
77
What are the pharyngeal constrictor muscles innervated by?
**Pharyngeal plexus.**
Sensory: Mainly the glossopharyngeal nerve, but the anterior and superior aspect of the nasopharynx is innervated by the maxillary nerve, and the inferior region of the laryngopharynx is innervated by a branch of the vagus nerve.
Motor: All muscles of the larynx are innervated by the vagus nerve, except for the stylopharyngeus muscle which is instead innervated by the glossopharyngeal nerve.
78
Describe the motor and sensory innervation of the tongue.
Motor:
* Hypoglossal nerve (XII) -\> All muscles (except palatoglossus, which is innverated by the vagus (X) nerve)
Sensory:
* Trigeminal nerve (V) -\> General sensation of anterior 2/3rds of tongue
* Facial nerve (VII) -\> Taste sensation of anterior 2/3rds of tongue
* Glossopharyngeal nerve (IX) -\> Both general and taste sensation of posterior 1/3rd
79
What are the muscles of mastication innervated by?
Mandibular branch of the trigeminal nerve (V)
80
What nerve innervates the upper and lower jaw?
Trigeminal nerve (V)
81
What nerve are the lips innervated by?
Trigeminal nerve (V)
82
Describe the nerves that innervate the nasal passage.
* Olfactory Nerve (I) -\> Smell
* Trigeminal Nerve (V) -\> General sensory
* Facial Nerve (VII) -\> Parasympathetic supply (of mucosa)
83
What nerve roots innervate the diaphragm?
C3, C4, C5 keep the diaphragm alive.
84
What nerves innervate the diaphragm?
* Motor and sensory -\> Phrenic nerve
* Sensory -\> Intercostal nerves
85
Briefly describe the innervation of the heart.
* A cardiac plexus which receives nerves from both the sympathetic and parasympathetic (vagus) systems is located beneath the arch of the aorta
* Sympathetic fibres innervate both the SAN and AVN, and also the cardiac muscle. Sympathetic activation causes an increase in heart rate and force of contraction.
* (Parasympathetic) Vagal fibres end primarily on the SAN and cause slowing of the heart.
86
What nerves innervate arterioles?
Sympathetic nerves
87
Briefly describe the innervation of the circulatory system.
* Arteries -\> Post-ganglionic sympathetic fibres control arterial flow and pressure, especially through the diameter of arterioles and alpha receptors
* Veins -\> Constriction increases venous return to the heart (and therefore pre-load). The large veins are also innervated by postganglionic sympathetic nerves, which control their capacity.
88
Describe the organisation of major veins in the thorax and abdomen.
Superior vena cava: Confluence of right and left brachiocephalic veins, which are confluences of:
* Internal jugular veins (drain head) and subclavian veins (drain external jugular veins and upper limb)
* Drain the azygos vein just before the SVC enters the right atrium
* Intercostal veins drain into the azygos vein on the right and the hemi-azygos veins on the left side of the thorax. The hemi-azygous veins drain into the azygous vein.
* Coronary sinus drains heart
Inferior vena cava:
* Drains the hepatic portal vein, which drains liver and alimentary tract (indirectly, via the hepatic portal veins)
* Drains the adrenals, kidneys, gonads, pelvic organs (corresponding veins to arteries)
* Drains the common iliac veins
89
Describe the structure of the vena cava and what it drains.
* Superior vena cava drains the head and upper limbs
* Drains the right brachiocephalic and left brachiocephalic veins, which each drain their corresponding internal jugular and subclavian veins
* Inferior vena cava drains the abdomen, pelvis and lower limbs
* Drains multiple tributaries, including the common iliac veins
90
Describe the structure of the common iliac arteries and veinsand what is flows to/from.
* Bifurcation of the aorta and inferior vena cava, respectively
* External arteries/veins go to lower limb
* Internal arteries/veins go to pelvis, buttock and perineum
91
What is the thoracic duct and what does it drain into?
* The largest lymph duct in the body, originating from about the T12 level.
* Drains into the left subclavian vein.
92
Describe the organisation of the lymphatic system.
* Lymph returns to blood vascular system at the junction of the subclavian and jugular veins (differences on R and L sides)
* Lymphatics that drain directly into the venous confluence:
* Head (jugular lymph trunks)
* Upper limb (subclavian lymph trunks)
* Bronchi & mediastinum (broncho-mediastinal lymph trunks) join venous confluence.
* Lymphatics that drain into the cisterna chyli, which is emptied into the confluence of the left internal jugular and subclavian veins by the thoracic duct:
* Lower limb & pelvis (external and internal iliac lymph trunks)
* Posterior abdominal wall (via para-aortic nodes to cisterna chyli)
* G-I tract (via midline pre-aortic nodes to cistern)
93
Which are the deep and which are the superficial veins in the upper limb?
Deep:
* Brachial
* Ulnar
* Radial
Superficial:
* Basilic
* Cephalic
* Median cubital
94
Describe the venous drainage of the thoracic cage.
* Posterior intercostal veins drain into the azygos, hemiazygos and accessory hemiazygos veins
* The hemiazygos and accessory hemiazygos veins drain into the azygos veins
* The azygos vein drains into the superior vena cava
95
Describe the blood supply to the duodenum.
96
Describe the blood supply to the liver and gall bladder.
97
Describe the blood supply to the pancreas.
It forms at the junction between the foregut and midgut, so it is supplied by both the coeliac and superior mesenteric arteries:
* Splenic artery (from coeliac artery)
* Anterior superior pancreaticoduodenal artery (from coeliac artery)
* Anterior inferior pancreaticoduodenal artery (from superior mesenteric artery)
98
Describe the blood supply to the rectum.
Superior part of the rectum:
* Superior rectal artery, which is a branch of the inferior mesenteric artery
Middle part of the rectum:
* Middle rectal artery, which is a branch of the internal iliac artery
Inferior part of the rectum
* Inferior rectal artery, which is a branch of the pudendal artery, which is a branch of the internal iliac artery
99
Describe the innervation of the anterior and anterolateral abdominal walls.
Ilioinguinal and iliohypogastric nerves innervate the lower parts of the abdomen.
100
Describe the venous drainage of the lungs and bronchi.
* Pulmonary veins drain the lungs -\> Drain into the left atrium of the heart.
* Bronchial veins drain the larger bronchi and structures at the roots of the lungs -\> The right side drains into the azygos vein, while the left side drains into the left superior intercostal vein or the accessory hemiazygos vein.
101
Describe the lymphatic drainage of the lungs and bronchi.
* Lymphatic drainage from lungs follows the tracheobronchial tree
* Majority of lymphatic drainage is to right lymphatic duct / subclavian vein except left upper lobe
102
Describe the blood supply and innervation of the foregut.
* Blood: Coeliac artery
* Innervation: T5-T9
103
Describe the blood supply and innervation of the midgut.
* Blood: Superior mesenteric artery
* Innervation: T10-T11
104
Describe the blood supply and innervation of the hindgut.
* Blood: Inferior mesenteric artery
* Innervation: T12-L1
105
What are the branches of the superior mesenteric artery?
106
What are the branches of the inferior mesenteric artery?
107
What nerve provides parasympathetic innervation to the oesophagus?
Vagus
108
What nerve root innervates the appendix?
T10
109
Compare the muscles and innervation of the two anal sphincters.
Internal anal sphincter:
* Smooth muscle
* Autonomic control
External anal sphincter:
* Striated muscle
* Pudendal nerve (s2-S4) control
110
What stimulates pepsinogen release from Chief (zymogenic) cells?
Vagus nerve stimulation
111
What are the two nerve plexuses in the gut?
* Meissner's/submucosal plexus -\> lies in the submucosal layer, mediates:
* Secretory function
* Mucosal movement
* Localised blood flow
* Auerbach's/myenteric plexus -\> lies in the muscularis layer, mediates:
* Outer muscularis muscle layer -\> Responsible for peristaltic activity
112
Are Meissner's and Auerbach's plexuses sympathetic or parasympathetic?
* Meissner's -\> Parasympathetic
* Auerbach's -\> Sympathetic and parasympathetic
113
What artery supplies the appendix of the large intestine?
Appendicular artery (originating from the superior mesenteric artery)
114
Describe what the coeliac artery supplies (and via what arteries it does this).
It has 3 main branches:
* Left gastric artery
* Lower part of oesophagus
* Stomach (anterior + posterior)
* Splenic artery
* Spleen
* Pancreas
* Stomach
* Common hepatic artery
* Stomach
* Duodenum
* Liver
115
Describe the drainage of the GI tract.
* All of the blood ultimately drains into the liver via the hepatic portal vein
* The hepatic portal vein is formed by the confluence of the splenic vein and the superior mesenteric vein
* The inferior mesenteric vein drains into the splenic vein before the confluence
* The organs drained by each are similar to those supplied by the corresponding arteries
116
Describe the blood supply to the kidneys.
* The renal arteries branch as they enter the kidney into anterior and posterior branches.
* These then branch into interlobar arteries, which are “end arteries” that supply a segment of the kidneys.
* Each interlobar artery gives rise to arcuate arteries, which in turn form interlobular arteries (and give off the vasa recta), which supply the nephrons.
Note the difference between interlobar and interlobular!
117
Describe the blood supply to the bladder.
From the internal iliac supply via the vesicular arteries.
118
Which major artery supplies the pelvis?
Interior iliac artery
119
Describe how the internal iliac artery supplies different pelvic structures in males.
Internal iliac artery divides into an anterior and posterior divisions
It is only the anterior that we are interested in for now
It gives off:
* Umbilical artery -\> To bladder (via superior vesical artery)
* Obturator artery -\> To medial compartment of thigh
* Inferior vesical artery -\> To bladder, prostate and seminal vesicles
* Internal pudendal artery -\> To perineal structures (e.g. to external genitalia)
* Middle rectal artery -\> To rectum
* Inferior gluteal artery -\> To gluteal region
120
Describe how the internal iliac artery supplies different pelvic structures in females.
Internal iliac artery divides into an anterior and posterior divisions
It is only the anterior that we are interested in for now
It gives off:
* Umbilical artery -\> To bladder (via superior vesical artery)
* Obturator artery -\> To medial compartment of thigh
* Uterine artery -\> To uterus
* Vaginal artery (sometimes comes off uterine artery) -\> To vagina
* Internal pudendal artery -\> To perineal structures (e.g. to external genitalia)
* Middle rectal artery -\> To rectum
* Inferior gluteal artery -\> To gluteal region
Note: Some of the arteries are quoted as coming off the posterior rather than anterior division, but this is disputable so I have listed everything as coming off the anterior branch.
121
Draw a diagram showing the blood supply to the female reproductive system.
122
What is the glomerulus supplied and drained by?
* Supplied by afferent arteriole
* Drained by efferent arteriole
123
What nerves innervate the pelvic floor?
S3 and S4 (keep your shit off the floor)
124
Describe the location and difference between the internal and external sphincters of the bladder. [IMPORTANT]
Internal
* Involuntary
* Innervated by autonomic nerves
* Found superior to the prostate, just near the exit of the bladder
External
* Voluntary
* Innervated by somatic nerves
* Found inferior to the prostate, just next to the levator ani muscles
125
What are the autonomic nerves that innervate the bladder sphincters?
* Sympathetic: Presacral nerves (L1 and L2)
* Parasympathetic: Pelvic parasympathetic nerves (S2, S3 and S4)
These innervate the internal sphincter.
126
What are the somatic nerves that innervate the bladder sphincters?
Pudendal nerve innervates the external sphincter.
127
Describe the blood supply and drainage of the testis and epididymis. [IMPORTANT]
Blood supply:
* Each testis and epididmyis is supplied by a testicular artery, which is a branch of the aorta
Blood drainage:
* Each testis is drained by vesicular veins are arranged in a pampiniform venous plexus
* These pass through the inguinal canal that unite to form a single vein
* Left testicular vein -\> Drains into left renal vein
* Right testicular vein -\> Drains directly into IVC
128
Describe the blood supply of the ductus (vas) deferens, bladder and prostate.
Arterial supply (all derived from internal iliac artery):
* Ductus deferens -\> Umbilical artery
* Bladder and prostate -\> Superior and inferior vesicular arteries
Venous drainage:
* Prostate -\> Drains back to vertebral venous plexus
129
Describe the arterial blood supply and drainage of the penis.
Pudendal artery branches into:
* Dorsal artery -\> Supplies dorsal surface of penis
* Deep artery -\> Supplies corpus cavernosum
Superficial and deep dorsal veins drain the penis.
130
What are the 3 main arteries supplying the female reproductive system? What do these branch from?
* Uterine artery -\> From abdominal aorta
* Ovarian artery -\> From internal iliac artery
* Vaginal artery -\> From internal iliac artery or ovarian artery
131
Describe the blood supply and drainage of the ovaries. [IMPORTANT]
Supply:
* Ovarian artery -\> From the abdominal aorta
Drainage:
* Drains to the IVC
132
Describe the blood supply and drainage of the uterus. [IMPORTANT]
Supply:
* Uterine artery from the internal iliac artery
Drainage:
* Internal iliac vein
133
Describe the blood supply to the vagina.
Vaginal artery, which is a branch of the internal iliac artery or uterine artery.
134
What does the internal pudendal artery supply and what is its path?
* It supplies the perineum and external genitalia
* It is a branch of the internal iliac artery
* Exits the pelvis via the greater sciatic foramen and enters the perineum via the lesser sciatic foramen, passing through the pudendal canal
135
Describe the blood supply to the penis and scrotum.
The supply to the penis comes from the internal pudendal artery (a branch of the internal iliac artery):
* Artery of bulb -\> Supplies the bulb of the penis
* Deep artery of penis -\> Supplies corpus cavernosum
* Dorsal artery of penis -\> Supplies distal corpus spongiosum and facial skin of penis
* (The internal pudendal artery also gives rise to the posterior scrotal artery that supplies some of the scrotum)
The supply to the scrotum comes from the external pudendal artery (a branch of the femoral artery):
* Anterior scrotal artery -\> Supplies most of the scrotum
136
Describe the blood supply and drainage of the ovaries.
Each ovary receives an ovarian artery from the aorta and drains into a pampiniform plexus of veins.
137
Describe the blood supply to an ovarian follicle.
The blood supply to the developing follicle is restricted to the thecal layer.
138
What arteries supply the endometrium?
Spiral arteries
139
Describe the lymphatic drainage of the testis.
Lymphatic vessels run alongside the arteries and drain into para-aortic lymph nodes.
140
What is the innervation of the cremaster muscle?
Innervated by the genital branch of the genitofemoral nerve (L1/L2).
141
What type of nerve fibres is the dartos muscle innervated by?
Sympathetic
142
Describe the innervation of the muscles that assist the functioning of the penis (bulbospongiosus and ischiocavernosus).
Pudendal nerve (S2-S4)
143
Which nervous system is responsible for erection?
Parasympathetic
144
Which nervous system is responsible for emission of semen (not ejaculation!)?
Sympathetic
145
Which nervous system is responsible for ejaculation of semen?
Somatic
146
Describe how erection occurs.
Normally, the helicine arteries of the corpora are contracted, so that little blood flows into the penis
Parasympathetic contribution to erection:
* When achieving erection, the helicine arteries of corpora relax
* Cavernous nerves (S2-S4)
Somatic contribution to erection:
* Contraction of bulbospongiosus and ischiocavernosus impedes venous return
* Pudendal nerve
147
What are the seminal vesicles innervated by?
Sympathetic nerves
148
What is the prostate gland innervated by?
Sympathetic nerves
149
Which nerve and muscles control ejaculation?
* Bulbospongiosus muscle and anal sphincter
* Controlled by the pudendal nerve (somatic)
150
Describe and explain the innervation of the female reproductive tract.
The pelvic pain line divides the female reproductive tract, passing just above the cervix
Above this line:
* All the structures (uterus, Fallopian tubes and ovaries) are covered by parietal peritoneum (they are intraperitoneal)
* Innervated by sympathetic and visceral afferent nerves (T12-L2)
Below this line:
* All of the structures (cervix and vagina) are subperitoneal (not covered by the parietal peritoneum)
* Pelvic splanchnics S2-S4 (parasympathetic) provide most of the innervation
* Pudendal nerves S2-S4 (parasympathetic) provide the innervation to the distal vagina and perineum
151
What is a good way to remember pelvic innervation?
* If something is innervated by parasympathetic fibres, it is very likely to be innervated by the S2-S4 level, especially the pudendal nerve
* If something is innervated by sympathetic fibres, it is likely to be from the thoracic and lumbar regions, since this is where sympathetic fibres come from
152
What nerves innervate above the pelvic pain line?
Sympathetic + Visceral afferents (T12-L2)
153
What nerves innervate below the pelvic pain line?
* Pelvic splanchnics S2-S4 (parasympathetic) provide most of the innervation
* Pudendal nerves S2-S4 (parasympathetic) provide the innervation to the distal vagina and perineum
154
What are two important erectile muscles in females? Where are they found? What is the innervation of these?
* Bulbospongiosus
* Ischiocavernosus
They are found in the superficial perineal pouch, just inferior to the perineal membrane. They are innervated by S2-S4 pudendal nerve.
155
Describe the vasculature of the hypothalamus and pituitary.
* Posterior pituitary receives blood supply direct from internal carotid artery
* Hypothalamus receives branches direct from internal carotid artery -\> These form a capillary plexus in the base of the hypothalamus that forms portal veins which supply the anterior pituitary.
* Anterior pituitary receives blood from hypothalamo-hypophysial portal veins.
156
Describe the blood supply to the thyroid.
* Superior thyroid artery -\> First branch of the external carotid artery.
* Inferior thyroid artery -\> Arises from the thyrocervical trunk (which in turn is a branch of the subclavian artery).
157
Describe the blood supply and drainage of the adrenal glands. [IMPORTANT]
Arterial supply:
* Branches of the inferior phrenic artery, the renal arteries and the aorta.
* These small arteries form an arterial plexus beneath the capsule surrounding the adrenal and then enter a sinusoidal system that penetrates the cortex and the medulla draining into a single central adrenal vein in each gland.
Venous drainage:
* The veins drain to the inferior vena cava (R) and renal vein (L).
158
What innervation stimulates insulin secretion? What inhibits it?
Stim: Parasympathetic
Inhib: Sympathetic
159
What innervation stimulates glucagon secretion?
Sympathetic innervation
160
What are the nerves of the 3rd, 4th and 6th pharyngeal arch and what do they innervate?
161
Describe the innervation of the adrenal glands.
* Principally to the medulla.
* Innervated by thoracic preganglionic sympathetic nerves which release ACh, acts at nicotinic receptors -\> NOTE that this is unusual because there are no post-ganglionic nerves.
162
What are the 3 main pairs of arteries draining the early embryo? What do they drain into?
* Vitelline veins
* Cardinal veins
* Umbilical veins
They all drain into the sinus venosus of the early heart.
163
Summarise the innervation of the pelvis, perineum and lower limbs.
* Sympathetic and parasympathetic (S2-S4) supply to the pelvic organs
* Sacral nerve somatic nerve supply to the perineum and lower limb
164
What do the vitelline veins drain in the early embryo?
Yolk sac
165
What do the cardinal veins drain in the early embryo?
Body
166
What do the umbilical veins drain in the early embryo?
Placenta
167
Which spinal nerve roots grow into the upper and lower limbs?
* Upper limb = C5-T1/2
* Lower limb = L2-S2
168
Describe the blood supply to the different pharyngeal arches.
Each pharyngeal arch is supplied by a different aortic arch.
169
For the 1st pharyngeal arch, state the derived:
* Nerves
* Muscles
* Skeletal elements
* Nerves -\> Trigeminal nerve
* Muscles -\> Muscles of mastication
* Skeletal elements -\> Maxilla and mandible, Malleus and incus
170
For the 2nd pharyngeal arch, state the derived:
* Nerves
* Muscles
* Skeletal elements
* Nerves -\> Facial
* Muscles -\> Muscles of facial expression
* Skeletal elements -\> Styloid process + Stapes
171
For the 3rd pharyngeal arch, state the derived:
* Nerves
* Muscles
* Skeletal element
* Nerves -\> Glossopharyngeal nerve
* Muscles -\> Stylopharyngeal muscle
* Skeletal element -\> Hyoid bone
172
For the 4th (and some of 6th) pharyngeal arch, state the derived:
* Nerves
* Muscles
* Skeletal elements
* Nerves -\> Vagus (6th also said to include accessory nerve)
* Muscles -\> Pharyngeal and laryngeal muscles
* Skeletal elements -\> Laryngeal cartilages
173
What is the nerve of the 1st pharyngeal arch and what does it innervate?
Trigeminal nerve:
* Motor -\> Muscle of mastication
* Sensory -\> Skin of face, Oral and nasal mucosa, Anterior 2/3rd of tongue
174
What is the nerve of the 2nd pharyngeal arch and what does it innervate?
Facial nerve:
* Motor -\> Muscles of facial expression
* Sensory -\> Anterior 2/3rd of tongue (taste)
175
Describe the innervation of the bronchi.
Pulmonary branches of the vagus nerve (X).
176
Summarise the sympathetic and parasympathetic innervation of the gut.
177
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