Lecture 10 - Revision Flashcards
What are the 2 main nerves to know in the thorax?
- Vagus nerve
- Phrenic nerve
What are the features of the vagus nerve?
- Also known as CNX (Cranial Nerve)
- Paired - arise from the brainstem
Where is the Vagus nerve distributed?
Extensively distributed in the body
- descend through the neck and enter thorax via the Superior thoracic aperture
- descend in the thorax posterior to the root of the lung on the surface of the oesophagus forming VAGAL TRUNKS
What is the innervation from the Vagus nerve?
Innervation to the thoracic viscera (heart, lungs), before penetrating the diaphragm with the oeseophagus to supply the abdominal viscera (liver/gallbladder, spleen, kidneys/suprarenals, pancreas, GI tract to splenic flexure)
What are features of the phrenic nerve?
Paired, arise at the neck from C3-C5
Descend through the neck and enter thorax via the superior thoracic aperture (lateral to vagus)
What is the pathway of the right phrenic nerve?
Right phrenic nerve –> over brachiocephalic artery, descends, anterior root of lung over right atrium
- end at the diaphragm
What is the pathway of the left phrenic nerve?
Left phrenic nerve –> over the pericardium of the left ventricle, anterior to the roof of the lung
- end at the diaphragm
What is innervated by the phrenic nerve?
- pericardium & diaphragm
Describe foetal circulation
- In foetus, nonfunctional lungs are bypassed
- blood from placenta –> right atrium –> left atrium through
-blood continues to left ventricle –> aortic value –> ascending aorta –> arch of the aorta –> descending aorta –> thorax - At the descending aorta, DUCTUS ARTERIOSUS connects with pulmonary trunk to supply lungs (not to oxygenate, just to perfuse the pulmonary).
What are the 2 main coronary arteries?
- Left coronary artery
- Right coronary arteru
Where do the left and right and right coronary arteries arise from?
Arise from the ascending aorta, just above the aortic valve
What does the right coronary artery split into?
- right marginal artery
- posterior descending artery
What does the left coronary artery split into?
- left circumflex artery
- left anterior descending artery
Describe dominance into which coronary artery makes up the posterior descending (intraventricular) artery
Right dominance - 70-80%
Left dominance - 5-10%
Co-dominance - 20%
What is the systemic venous system?
returns blood to the right atrium of the heart
What is the portal venous system?
transports venous blood to the liver for processing (eliminating toxins and metabolites, such as ammonia) BEFORE going back into the systemic venous system.
- carries oxygen-poor/nutrient-rich blood
What drains into the portal venous system?
GI tract (lower esophagus to upper anal canal)
SMV (superior mesenteric vein) - drains blood from the small intestine and part of the large intestine
IMV (inferior mesenteric vein) - drains blood from the distal colon and rectum
- same arrangement and areas as arteries
Other abdominal organs (spleen, pancreas) via splenic and pancreatic veins
What are the 3 vessels that enter/leave the liver via the Porta Hepatis (inferior surface of liver)?
- Common hepatic bile duct (leaving)
- Proper hepatic artery (entering)
- Hepatic PORTAL vein (entering)
Where does the hepatic vein travel into?
IVC (inferior vena cava)
What is the anterior blood supply of the abdomen?
- Coeliac trunk @T1 - foregut
- Superior mesenteric artery (SMA) @L1 - midgut
- Inferior mesenteric artery (IMA) @L3 - hindgut
What are the branches of the Coelic trunk?
Left gastric artery –> oesophagus and superior lesser curvature stomach
Splenic artery (Short gastric + left gastroepiploic) –> neck, body and tail of pancreas, spleen
- short gastric arteries –> fundus stomach
- left gastroepiploic artery –> superior greater curvature of the stomach
Common hepatic artery (proper hepatic (right gastric) + gastroduodenal artery (right gastroepiploic + superior pancreaticoduodenal)
- proper hepatic artery –> liver & gallbladder
- right gastric –> inferior lesser curvature stomach
- right gastroepiploic artery –> inferior greater curvature of the stomach
- superior pancreaticoduodenal artery –> superior part of duodenum and head of pancreas
What are the branches of the SMA (superior mesenteric artery)?
- inferior pancreaticoduodenal artery –> pancreas and last past of duodenum
- jejunal and ileal arteries –> jejunum and ileum
- ileocolic artery –> ileocecal junction
- right colic artery –> ascending colon
- middle colic artery –> ascending colon and 2/3 of transverse colon
What are branches of the IMA (inferior mesenteric artery)?
- Left colic artery –> last 1/3 transverse colon and descending colon
- Sigmoid (or sigmoidal) arteries) –> last part of descending colon and sigmoid colon
- Superior rectal artery –> upper rectum
What is the rectum suppled by?
superior rectum - inferior mesenteric artery
middle rectum - internal iliac artery
inferior rectum - internal pudendal artery
What are other branches to the abdomen?
Renal artery - (L1/2) –> kidneys
Gonadal arteries (L2)
- ovarian artery –> travels within suspensory ligament of ovary –> ovary and part of the uterus
- testicular artery –> travels within spermatic cord –> testis
Bifurcation into L/R common iliac arteries (L4)
- internal iliac artery (stays in and supplies pelvis (vagina & uterus)
- (internal pudendal artery –> penis, vulva, clitoris)
- external iliac artery –> passes under inguinal ligament and becomes femoral artery (for lower limb)
Describe the contents of the inguinal canal
- Short oblique passageway from abdominal cavity to anterior abdomen
- Formed from muscles and their aponeuroses
- Follows the inguinal ligaments (from anterior superior iliac spine - ASIS - to pubic tubercle)
What is the entrance/exit of the inguinal canal?
Entrance - deep inguinal ring
Exit - superficial inguinal ring
Describe the inguinal canal in females?
Ilioinguinal nerve (innervates skin covering the mons pubis and labia majora + motor innervation of the transversus abdominis and obliques muscles)
Round ligament of the uterus (attaches uterus to labia majora)
Genital branch of the genitofemoral nerve (innervates skin covering the mons pubis and labia majora)
Describe the inguinal canal in males?
Ilioinguinal nerve (innervates skin over the root of the penis and upper part of the scrotum + motor innervation of the transversus abdominis and obliques muscles
- Spermatic cord
What are the structures in inguinal canal to and form testis?
Contents:
- Vas deferens
- Testicular artery
- Testicular veins (pampiniform plexus)
- Genital branch of the genitofemoral nerve (innervates cremaster and dartos muscle)
- lymphatics
- autonomic nerves
