innervation and blood supply (for transfer)

Question 1

What is the ductus arteriosus?

Answer 1

• 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.

Question 2

What supplies blood to the heart?

Answer 2

Coronary arteries

Question 3

What are the different coronary arteries?

Answer 3

• 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.

Question 4

What is the venous drainage for the heart?

Answer 4

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.

Question 5

What is the arterial blood supply of the head?

Answer 5

• 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.

Question 6

What is the venous supply of the head?

Answer 6

• 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.

Question 7

Describe the arterial supply to the upper limb.

Answer 7

Question 8

Describe the arterial supply to the lower limb.

Answer 8

Question 9

What vessel supplies oxygenated blood to the dorsal surface of the foot?

Answer 9

Dorsalis pedis

Question 10

Describe the venous drainage of the lower limb.

Answer 10

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.

Question 11

What vessels supply oxygenated blood to the walls of large veins and arteries?

Answer 11

Vasa vasorum (‘vessels of vessels’)

Question 12

What is the organisation of the major vessels in the thorax?

Answer 12

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).

Question 13

What is the organisation of the major vessels in the abdomen?

Answer 13

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).

Question 14

What major vessel supplies the head?

Answer 14

Common carotid, which bifurcates into the external and internal carotid arteries. (On the RHS, this originates from the brachiocephalic artery).

Question 15

What major vessel supplies the upper limb and part of the thorax and neck?

Answer 15

The subclavian artery. (On the RHS, this originates from the brachiocephalic artery).

Question 16

What major vessel supplies the foregut?

Answer 16

Coeliac artery (T12)

Question 17

What major vessel supplies the midgut?

Answer 17

Superior mesenteric artery (L1)

Question 18

What major vessel supplies the hindgut?

Answer 18

Inferior mesenteric artery (L3)

Question 19

Which artery supplies the gonads?

Answer 19

Gonadal arteries (paired, L2)

Question 20

Which artery supplies the kidneys?

Answer 20

Renal arteries (L1)

Question 21

What major vessel supplies the lower limb and pelvis?

Answer 21

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).

Question 22

What artery supplies most of the thigh with oxygenated blood?

Answer 22

Deep femoral artery (profunda femoris)

Question 23

Describe the aortic supply of the thoracic cage.

Answer 23

• 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.

Question 24

What arteries supply the lungs?

Answer 24

• Pulmonary arteries -> Supply exchange parts of the lungs
• Bronchial arteries -> Supply non-exchange parts of the lungs (e.g. bronchi)

Question 25

What arteries supply the nasal mucosa?

Answer 25

Originating from the internal and external carotid supply: * Maxillary artery * Facial artery * Branches of the ophthalmic artery

Question 26

Describe the nerves that innervate the nasal passage.

Answer 26

* Olfactory Nerve (I) -\> Smell * Trigeminal Nerve (V) -\> General sensory * Facial Nerve (VII) -\> Parasympathetic supply (of mucosa)

Question 27

What nerve innervates the trachea?

Answer 27

Pulmonary plexus: * Recurrent laryngeal nerves (branches of the vagus) -\> Parasympathetic supply * Sympathetic trunks -\> Sympathetic supply

Question 28

What nerves innervate the larynx?

Answer 28

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.

Question 29

What are the pharyngeal constrictor muscles innervated by?

Answer 29

**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.

Question 30

Describe the motor and sensory innervation of the tongue.

Answer 30

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

Question 31

What are the muscles of mastication innervated by?

Answer 31

Mandibular branch of the trigeminal nerve (V)

Question 32

What nerve innervates the upper and lower jaw?

Answer 32

Trigeminal nerve (V)

Question 33

What nerve are the lips innervated by?

Answer 33

Trigeminal nerve (V)

Question 34

Describe the nerves that innervate the nasal passage.

Answer 34

* Olfactory Nerve (I) -\> Smell * Trigeminal Nerve (V) -\> General sensory * Facial Nerve (VII) -\> Parasympathetic supply (of mucosa)

Question 35

What nerve roots innervate the diaphragm?

Answer 35

C3, C4, C5 keep the diaphragm alive.

Question 36

What nerves innervate the diaphragm?

Answer 36

* Motor and sensory -\> Phrenic nerve * Sensory -\> Intercostal nerves

Question 37

Briefly describe the innervation of the heart.

Answer 37

* 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.

Question 38

What nerves innervate arterioles?

Answer 38

Sympathetic nerves

Question 39

Briefly describe the innervation of the circulatory system.

Answer 39

* 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.

Question 40

Describe the organisation of major veins in the thorax and abdomen.

Answer 40

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

Question 41

Describe the structure of the vena cava and what it drains.

Answer 41

* 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

Question 42

Describe the structure of the common iliac arteries and veinsand what is flows to/from.

Answer 42

* 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

Question 43

What is the thoracic duct and what does it drain into?

Answer 43

* The largest lymph duct in the body, originating from about the T12 level. * Drains into the left subclavian vein.

Question 44

Describe the organisation of the lymphatic system.

Answer 44

* 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)

Question 45

Which are the deep and which are the superficial veins in the upper limb?

Answer 45

Deep: * Brachial * Ulnar * Radial Superficial: * Basilic * Cephalic * Median cubital

Question 46

Describe the venous drainage of the thoracic cage.

Answer 46

* 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

Question 47

Describe the venous drainage of the lungs and bronchi.

Answer 47

* 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.

Question 48

Describe the lymphatic drainage of the lungs and bronchi.

Answer 48

* Lymphatic drainage from lungs follows the tracheobronchial tree * Majority of lymphatic drainage is to right lymphatic duct / subclavian vein except left upper lobe

Question 49

Describe the blood supply and innervation of the foregut.

Answer 49

* Blood: Coeliac artery * Innervation: T5-T9

Question 50

Describe the blood supply and innervation of the midgut.

Answer 50

* Blood: Superior mesenteric artery * Innervation: T10-T11

Question 51

Describe the blood supply and innervation of the hindgut.

Answer 51

* Blood: Inferior mesenteric artery * Innervation: T12-L1

Question 52

Describe the blood supply to the duodenum.

Answer 52

Question 53

Describe the blood supply to the liver and gall bladder.

Answer 53

Question 54

Describe the blood supply to the pancreas.

Answer 54

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)

Question 55

Describe the blood supply to the rectum.

Answer 55

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

Question 56

Describe the innervation of the anterior and anterolateral abdominal walls.

Answer 56

Ilioinguinal and iliohypogastric nerves innervate the lower parts of the abdomen.

Question 57

What nerve provides parasympathetic innervation to the oesophagus?

Answer 57

Vagus

Question 58

What nerve root innervates the appendix?

Answer 58

T10

Question 59

Compare the muscles and innervation of the two anal sphincters.

Answer 59

Internal anal sphincter: * Smooth muscle * Autonomic control External anal sphincter: * Striated muscle * Pudendal nerve (s2-S4) control

Question 60

What stimulates pepsinogen release from Chief (zymogenic) cells?

Answer 60

Vagus nerve stimulation

Question 61

What are the two nerve plexuses in the gut?

Answer 61

* 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

Question 62

Are Meissner's and Auerbach's plexuses sympathetic or parasympathetic?

Answer 62

* Meissner's -\> Parasympathetic * Auerbach's -\> Sympathetic and parasympathetic

Question 63

What artery supplies the appendix of the large intestine?

Answer 63

Appendicular artery (originating from the superior mesenteric artery)

Question 64

Describe what the coeliac artery supplies (and via what arteries it does this).

Answer 64

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

Question 65

Describe the drainage of the GI tract.

Answer 65

* 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

Question 66

What are the branches of the superior mesenteric artery?

Answer 66

Question 67

What are the branches of the inferior mesenteric artery?

Answer 67

Question 68

Describe the blood supply to the kidneys.

Answer 68

* 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!

Question 69

Describe the blood supply to the bladder.

Answer 69

From the internal iliac supply via the vesicular arteries.

Question 70

Which major artery supplies the pelvis?

Answer 70

Interior iliac artery

Question 71

Describe how the internal iliac artery supplies different pelvic structures in males.

Answer 71

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

Question 72

Describe how the internal iliac artery supplies different pelvic structures in females.

Answer 72

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.

Question 73

What is the glomerulus supplied and drained by?

Answer 73

* Supplied by afferent arteriole * Drained by efferent arteriole

Question 74

What nerves innervate the pelvic floor?

Answer 74

S3 and S4 (keep your shit off the floor)

Question 75

Describe the location and difference between the internal and external sphincters of the bladder. [IMPORTANT]

Answer 75

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

Question 76

What are the autonomic nerves that innervate the bladder sphincters?

Answer 76

* Sympathetic: Presacral nerves (L1 and L2) * Parasympathetic: Pelvic parasympathetic nerves (S2, S3 and S4) These innervate the internal sphincter.

Question 77

What are the somatic nerves that innervate the bladder sphincters?

Answer 77

Pudendal nerve innervates the external sphincter.

Question 78

Describe the blood supply and drainage of the testis and epididymis. [IMPORTANT]

Answer 78

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

Question 79

Describe the blood supply of the ductus (vas) deferens, bladder and prostate.

Answer 79

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

Question 80

Describe the arterial blood supply and drainage of the penis.

Answer 80

Pudendal artery branches into: * Dorsal artery -\> Supplies dorsal surface of penis * Deep artery -\> Supplies corpus cavernosum Superficial and deep dorsal veins drain the penis.

Question 81

What are the 3 main arteries supplying the female reproductive system? What do these branch from?

Answer 81

* Uterine artery -\> From abdominal aorta * Ovarian artery -\> From internal iliac artery * Vaginal artery -\> From internal iliac artery or ovarian artery

Question 82

Describe the blood supply and drainage of the ovaries. [IMPORTANT]

Answer 82

Supply: * Ovarian artery -\> From the abdominal aorta Drainage: * Drains to the IVC

Question 83

Describe the blood supply and drainage of the uterus. [IMPORTANT]

Answer 83

Supply: * Uterine artery from the internal iliac artery Drainage: * Internal iliac vein

Question 84

Describe the blood supply to the vagina.

Answer 84

Vaginal artery, which is a branch of the internal iliac artery or uterine artery.

Question 85

Draw a diagram showing the blood supply to the female reproductive system.

Answer 85

Question 86

What does the internal pudendal artery supply and what is its path?

Answer 86

* 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

Question 87

Describe the blood supply to the penis and scrotum.

Answer 87

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

Question 88

Describe the blood supply and drainage of the ovaries.

Answer 88

Each ovary receives an ovarian artery from the aorta and drains into a pampiniform plexus of veins.

Question 89

Describe the blood supply to an ovarian follicle.

Answer 89

The blood supply to the developing follicle is restricted to the thecal layer.

Question 90

What arteries supply the endometrium?

Answer 90

Spiral arteries

Question 91

Describe the lymphatic drainage of the testis.

Answer 91

Lymphatic vessels run alongside the arteries and drain into para-aortic lymph nodes.

Question 92

What is the innervation of the cremaster muscle?

Answer 92

Innervated by the genital branch of the genitofemoral nerve (L1/L2).

Question 93

What type of nerve fibres is the dartos muscle innervated by?

Answer 93

Sympathetic

Question 94

Describe the innervation of the muscles that assist the functioning of the penis (bulbospongiosus and ischiocavernosus).

Answer 94

Pudendal nerve (S2-S4)

Question 95

Which nervous system is responsible for erection?

Answer 95

Parasympathetic

Question 96

Which nervous system is responsible for emission of semen (not ejaculation!)?

Answer 96

Sympathetic

Question 97

Which nervous system is responsible for ejaculation of semen?

Answer 97

Somatic

Question 98

Describe how erection occurs.

Answer 98

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

Question 99

What are the seminal vesicles innervated by?

Answer 99

Sympathetic nerves

Question 100

What is the prostate gland innervated by?

Answer 100

Sympathetic nerves

Question 101

Which nerve and muscles control ejaculation?

Answer 101

* Bulbospongiosus muscle and anal sphincter * Controlled by the pudendal nerve (somatic)

Question 102

Describe and explain the innervation of the female reproductive tract.

Answer 102

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

Question 103

What is a good way to remember pelvic innervation?

Answer 103

* 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

Question 104

What nerves innervate above the pelvic pain line?

Answer 104

Sympathetic + Visceral afferents (T12-L2)

Question 105

What nerves innervate below the pelvic pain line?

Answer 105

* Pelvic splanchnics S2-S4 (parasympathetic) provide most of the innervation * Pudendal nerves S2-S4 (parasympathetic) provide the innervation to the distal vagina and perineum

Question 106

What are two important erectile muscles in females? Where are they found? What is the innervation of these?

Answer 106

* Bulbospongiosus * Ischiocavernosus They are found in the superficial perineal pouch, just inferior to the perineal membrane. They are innervated by S2-S4 pudendal nerve.

Question 107

Describe the vasculature of the hypothalamus and pituitary.

Answer 107

* 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.

Question 108

Describe the blood supply to the thyroid.

Answer 108

* 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).

Question 109

Describe the blood supply and drainage of the adrenal glands. [IMPORTANT]

Answer 109

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).

Question 110

What innervation stimulates insulin secretion? What inhibits it?

Answer 110

Stim: Parasympathetic Inhib: Sympathetic

Question 111

What innervation stimulates glucagon secretion?

Answer 111

Sympathetic innervation

Question 112

Describe the innervation of the adrenal glands.

Answer 112

* 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.

Question 113

What are the 3 main pairs of arteries draining the early embryo? What do they drain into?

Answer 113

* Vitelline veins * Cardinal veins * Umbilical veins They all drain into the sinus venosus of the early heart.

Question 114

What do the vitelline veins drain in the early embryo?

Answer 114

Yolk sac

Question 115

What do the cardinal veins drain in the early embryo?

Answer 115

Body

Question 116

What do the umbilical veins drain in the early embryo?

Answer 116

Placenta

Question 117

Which spinal nerve roots grow into the upper and lower limbs?

Answer 117

* Upper limb = C5-T1/2 * Lower limb = L2-S2

Question 118

Describe the blood supply to the different pharyngeal arches.

Answer 118

Each pharyngeal arch is supplied by a different aortic arch.

Question 119

For the 1st pharyngeal arch, state the derived: * Nerves * Muscles * Skeletal elements

Answer 119

* Nerves -\> Trigeminal nerve * Muscles -\> Muscles of mastication * Skeletal elements -\> Maxilla and mandible, Malleus and incus

Question 120

For the 2nd pharyngeal arch, state the derived: * Nerves * Muscles * Skeletal elements

Answer 120

* Nerves -\> Facial * Muscles -\> Muscles of facial expression * Skeletal elements -\> Styloid process + Stapes

Question 121

For the 3rd pharyngeal arch, state the derived: * Nerves * Muscles * Skeletal element

Answer 121

* Nerves -\> Glossopharyngeal nerve * Muscles -\> Stylopharyngeal muscle * Skeletal element -\> Hyoid bone

Question 122

For the 4th (and some of 6th) pharyngeal arch, state the derived: * Nerves * Muscles * Skeletal elements

Answer 122

* Nerves -\> Vagus (6th also said to include accessory nerve) * Muscles -\> Pharyngeal and laryngeal muscles * Skeletal elements -\> Laryngeal cartilages

Question 123

What is the nerve of the 1st pharyngeal arch and what does it innervate?

Answer 123

Trigeminal nerve: * Motor -\> Muscle of mastication * Sensory -\> Skin of face, Oral and nasal mucosa, Anterior 2/3rd of tongue

Question 124

What is the nerve of the 2nd pharyngeal arch and what does it innervate?

Answer 124

Facial nerve: * Motor -\> Muscles of facial expression * Sensory -\> Anterior 2/3rd of tongue (taste)

Question 125

What are the nerves of the 3rd, 4th and 6th pharyngeal arch and what do they innervate?

Answer 125