Anatomy Flashcards
What nerve does the inguinal canal contain?
-ilioinguinal nerve
Where does the inguinal canal extend from and too?
-It extends from the deep inguinal ring to the superficial inguinal ring
What marks the start of the spermatic cord?
-Once leaving the superficial ring thee are 3 layers of fascia = start of the spermatic cord.
What does the spermatic cord contain?
-Vas deferens, testicular artery, panpiniform plexus of veins, nerves and lymphatics of the testis and the processes vaginalis
Cause of an inguinal hernia?
Passage of part of the intestine or peritoneum into the inguinal canal- in males these hernias may pass into the spermatic cord
What hormone do the testes produce?
Testosterone
What sac partially surrounds the testes?
-Tunica vaginalis
What tube lays along the posterior border of each testis?
Epididymis
Fibres of what muscle are found under the scrotal skin?
Dartos muscle
What does the scrotum contain?
-Testes, epididymis and lower part of the spermatic cord
What makes up the body of the penis?
- 3 cylinders of erectile tissue
- 2 corpus cavernous and 1 corpus spongiosus
Once you reach the anterior superior iliac spine, which way do the anterior oblique muscle fibres run in?
Horizontally
Where do the lowermost fibres of the internal oblique muscle take their origin from and where do the fibres insert?
-They take their origin from the lateral 2/3rds of the inguinal ligament and insert on to the pubic tubercle
What acts to protect against hernias?
The lower fibres of the internal oblique arch over inguinal canal, contraction of these fibres closes the canal = protection from hernias
Where does the transverse muscle layer take its origin from?
Lateral 1/3rd of the inguinal ligament
How many layers of tissue cover the core contents of the inguinal canal?
-A single transversalis fascia layer
What are the 3 layers of fascia covering the inguinal canal called?
- Inner thin and loose transversalis fascia layer
- Middle cremesteric muscle layer: comes from internal oblique
- External spermatic fascia: comes from external oblique aponeurosis (only covered by 3 layers as they pass out of the superficial inguinal ring)
Why is having the testes in the scrotum and surrounded by the panpiniform plexus of veins beneficial?
-The veins dissipate heat and SA of scrotum helps to lower the temp of the testis. Spermatogenesis is optimal at a temp lower than body temp
What is the vas deferens and how is it distinguished?
- Duct which carries sperm from epididymis to the urethra
- It is a thick, larger and harder tube
What does the ilioinguinal nerve supply?
-Supplies skin over the base of the penis and the anterior third of the scrotum
What does the cremesteric muscle layer enable the testis to do?
Retract
What is the sac of peritoneum surrounding the testis called?
Tunica vaginalis
What is the connection from the tunica vaginalis to the abdomen called?
Processus vaginalis
How is a congenital indirect inguinal hernia formed?
The processus vaginalis does not obliterate forming a tube extending from the abdomen to the scrotum. When the baby cries, bowel is pushed into the tube
What are the 3 arteries and 3 veins of the spermatic cord
Arteries: testicular
artery of vas deferens
Cremesteric
Veins: testicular (panpiniform plexus)
Veins from vas deferens
Cremesteric veinWhat are the 3 nerves of the spermatic cord?
- Nerve to the cremaster (genital branch of genitofemoral)
- Inguinal branch of ilioinguinal nerve (supplies sensation to anterior 3rd of scrotum)
- Sympathetic nerves to vas and testes
What makes up the anterior and the posterior surface of the testicle?
- Anterior surface: the testicle itself
- Posterior: epididymis
What makes up the centre of the testis?
-Multiple microscopic seminiferous tubules
Why does the urethra need to be wide bore?
-This enables it to sustain a high urine flow rate with a low driving pressure from the bladder
What 3 cylinders of erectile tissue form the penis?
- 2 corpus cavernous a
- 2 corpus spongiosus
What is the corpus cavernous attached too and where does this tissue arise and end?
-It is attached to the pelvis and ends at the glans.
What forms the glans?
-Corpus spongiosum
What is the navicular fossa?
-A dilation within the urethra where the urethra is at it’s widest
What is the thick fascia covering the whole of the penis and what is it’s role?
-Bucks fascia: limits the amount of blood flowing to the penis during an erection
What supports the urethra during ejaculation?
-Upper part supported by prostate, lower by perineal membrane.
Where do the public rami extend as far as?
-ischial tuberositys
What creates the perineum?
- It is a triangle between the two inferior pubic rami
- one corner: pubic symphysis
- Two corners: ischial tuberositys
What creates the ano-rectal triangle?
-The two ischial tuberositys and the coccyx
What membrane almost fills the perineum?
-Perineal membrane
What muscle is below the perineal membrane and what does it form?
- Deep perineal pouch
- Forms from sphincters fro the vagina and the urethra in females
- Forms from just the urethra in males
What is ischio-cavernous so?
-It is a layer of skeletal muscle covering the cura cavernosa (groove between the perineal membrane and the inferior pubic rami where the corpus cavernosa arises)
What muscle covers the cure spongiosus?
-Bulbiospongiosus
Where is the orifice for the urethra and the vagina?
-Between the two labia minora
What supplies the distal part of the anal canal?
-S5: sacral spinal nerve
What is the peudendal nerve a branch of and what does it supply?
- Branch of the sacral roots 2,3 and 5
- Supplies the perineum: posterior 2/3 thirds of the external genitalia and the area of skin off the central buttocks and anal canal
What is the difference between a direct and indirect hernia?
- Direct: passes through the transverse fascia, directly through internal oblique layer and the directly through external ring.
- Indirect: occurs when the hernia passes along the length of the canal passing through the 3 layers of abdominal wall in a different position.
Where is lymph node metastasis located?
-Around the aorta in the upper abdomen
What nerve roots supply the kidney and gonads?
- T10-T12
- As these nerve roots extend from the midline at the back immediately posterior to the kidney, down to the groin and into the scrotum. Kidney pain can be felt in the scotum and gonadal pain in the loin.
What is hydrocoele
-disease occurs the testis of scrotum that cause fluid to collect in the tunica vaginalis = creates a swelling.
Where does the epididymis attach to the testis and where is it at it’s largest?
-Ductii efferentes- this is the head of the epididymis and it is at it’s largest here.
Where do the kidneys lie in relation to the peritoneum?
- Extra-peritoneal (outside)
- Retro-peritoneal (behind)
What kind of fat is each kidney embedded in and what fascia is it covered with?
- Perinephric fat
- Renal fascia
What border of the kidney is the renal hilum found at and what leaves the kidney here?
- Medial border
- Renal artery, renal vein, ureter, lymphatics and sympathetic nerves.
What is the perinephric fat of the kidney related to posteriorly?
-Muscles of the posterior abdominal wall; diaphragm; psoas major; quadratus lumborum and transversus abdominis.
What is the right and left kidney related to anteriorly?
- Right: liver, duodenum and coil of intestines
- Left: stomach, spleen, pancreas and coil of intestines
Where are the suprarenal glands found?
-Upper pole of each kidney deep in the Perinephric fat
What are the shapes of the two suprarenal glands and where do they lie?
- Right: tetrahedral and lies behind the liver and IVC
- Left: crescent shaped and lies behind the stomach and pancreas
What does the posterior abdominal wall consist of?
-Lumbar spine, psoas muscle and quadratus lumborum muscles
What structures rung along the posterior abdominal wall?
-IVC, aorta and associated autonomic plexus and lymph nodes
How do renal, adrenal and gonadal veins of the retro peritoneum on either side drain into the IVC.
- Right side: adrenal, renal and gonadal veins all drain into IVC separately.
- Left side: adrenal, renal and gonadal vein all join the renal vein which passes over the aorta to drain into the right side of the IVC.
What is a varicocoel and what can it be caused by?
- Swelling of the veins around the testis
- When tumours of the kidney compress the testicular vein.
What are the 3 arteries of the suprarenal glands and how many veins do they have?
Arteries: one from the renal artery; one from the aorta and the artery to the diaphragm
-A single vein
Name the structures anteriorly to posteriorly of the hilum
- Renal vein
- Renal artery almost immediately behind
- Ureter almost posteriorly
What is ‘water under the bridge in terms of the ureter and gonadal vessel?
-The ureter runs down towards the bladder and UNDER the gonadal vessel.
What fat is the kidney encased in?
-Perinephric
Where do tumours of the kidney tend to grow alongside?
-The renal vein
What could cause unilateral swelling of the scrotum?
-Tumour on the left side of the kidney within the renal vein that blocks the gonadal vein
Where does the gonadal artery arise from and where does the gonadal vein drain into?
- Arises from the aorta
- Gonadal vein drains into the IVC
What creates the granulated appearance inside the kidney?
-Blood vessels supplying the glomeruli
What is found at the tip of the medullary pyramids and what empties into this space?
- Minor calyx
- Collecting ducts
What do 2 or 3 minor calyx fuse to form?
-Major calyces
What do all major calyces fuse to form?
-Renal pelvis
What does the renal pelvis drain out through?
-Ureter
What forms the posterior limit in the upper part of the abdominal cavity?
-Diaphragm
What muscle runs between the 12th rib and the iliac crest?
-Quadratus lumborum muscle
What is termed the lateral and medial arcuate lines?
-where the diaphragm attaches to the fascia over the quadratus lumborum and psoas muscle
What is the median arcuate line?
-Where the diaphragm passes in front of the aorta
What muscle lies directly on the iliac bone and what nerve runs directly over this muscle?
- Iliacus muscle
- Lateral cutaneous nerve of the thigh
What does the lateral cutaneous nerve of the thigh supply?
-The skin of the lateral thigh
What does the femoral nerve supply and where does it run?
- Skin of the anterior thigh
- Runs in the groove between the iliacus and the psoas muscle
Where does the gentifemoral and obturator nerve run?
- Genitofemoral: anterior surface of psoas
- Obturator: medial surface of psoas
What is the origin of the psoas muscle and where does it attach?
- Origin: fascia on the sides of the lumbar vertebrae and intervertebral discs
- Attaches: lesser trochanter of the femur
What 3 nerves form a plexus in the psoas muscle?
- L2, 3 and 4
- Femoral nerve
- Obturator nerve
- Lateral femoral cutaneous nerve
Where does the aorta bifurcate?
-L4, level of the umbilicus
What does the aorta bifurcate into
Following this what and where is the second bifurcation?
- 2 common iliac arteries
- Internal and external iliac arteries and occurs at the sacroiliac joint
What does the external iliac artery become and what artery does it give off?
- External iliac artery gives off a number of arteries including the inferior epigastric
- As it passes under the inguinal ligament it becomes the femoral artery
What does the internal iliac artery split into and what does it have an anastomoses with?
- Anterior: supplies bladder, uterus and placenta
- posterior: forms the superior and inferior gluteal arteries in the buttock. Has an anastomoses with the profundo-femoral artery.
Where does the rectum receive it’s blood supply from?
-Inferior mesenteric artery
What does the obturator nerve supply?
-Supplies sensation to the medial part of the thigh down to the knee and motor supply to the medial compartment of the thigh
What three bones make up the innominate bone?
- Ileum
- Ischium
- Pubis
How are the two hemipelvis connected at the front and back?
- They are connected at the midline with a secondary cartilaginous joint at the front.
- They are connected posteriorly at the sacrum by the sacro-iliac joint
What does the pubic bone consist of?
- Superior pubic rami
- Pubic tubercle
- Body of the pubis
- First third of the inferior pubic Ramus
What is the anterior superior iliac spine the attachment for?
inguinal ligament
What plane is between the two tuberositys and what does this separate?
- Intertubercular plane
- The middle third from the lower third of the abdomen
What plane is between the two highest points on the posterior pelvis?
- Intercristal plane
What spineous processes does the intercristal plane pass through?
-L4 and L5
What kind of joint is the sacro-iliac joint?
-Mixed: has fibrocartilage between the bones but has some synovial and a synovial cavity
Where does the sciatic nerve pass in to the buttock and what ligaments create this foramina?
- Greater sciatic notch
- Ischiasacral ligament
- Spinosacral ligament
What ligament stretches from the ischial tuberosity to the sacrum?
-Ischiosacral ligament
Explain the difference in the angel between the inferior pubic rami in a male and a female
- Male: ‘V’ shaped- it needs to be as straight as possible to prevent damage to penis and it’s attachments during intercourse
- Female: more open shallow angle. This is because it needs to be as wide as possible for the delivery of a child
What anatomy of the pelvis in a male allows for support of upper body mass?
-The spine of the ischium points straight towards the sacrum and there is a smaller distance. Allows a greater amount of weight to pass through the ligaments
What anatomy of the pelvis in a female allows for passage of a baby?
-In females the distance between the ischium and the sacrum is greater to give a wider outlet to the pelvis for the passage of the baby.
What sheet of muscle prevents prolapse of the bowel?
-Levator Ani
What does the levator ani muscle attach too?
-Back of the pubic, fascia of the obturator internus, spine of the ischium and to the sacrum and coccyx.
What midline do the fibres of the levator and muscle attach too?
-Midline raphe
What is the action of the contraction of the levator ani muscle?
-Raises the anal canal
What are the 4 surfaces of the bladder?
- Superior surface covered with peritoneum
- 2 lateral surfaces lying against the side of the pelvis
- A base which lies posteriorly against the rectum or vagina
What word is used to describe most of the internal lining of the bladder and what does this lining allow the bladder to do?
- Rugose
- Allows the bladder to distend with urine
What is the name of the smooth walled triangle in the bladder between the orifices for the 2 ureters.
-The trigone
Where is the thyroid gland located?
- Anterior neck
- Between C5 and T1 vertebrae
- Straddles trachea
- Lies behind sternohyoid and sternothyroid muscles
- Wraps around cricoid cartilage & superior tracheal rings
- Lies inferior to thyroid cartilage of the larynx
What divides the 2 lobes of the thyroid ?
Isthmus
Why is the thyroid highly vascularised?
It secrets hormones directly into the blood
Explain the arteries of the thyroid
- Superior thyroid artery : branch of external carotid artery & supplies anterior and superior portion
- Inferior thyroid artery : Aries from the thyrocervical trunk which is a branch of subclavian artery. It supplies posterior and inferior aspect
What is the innervation of the thyroid
Branches from sympathetic trunk
What controls the release of hormones from the thyroid?
Pituitary gland
Where is the pituitary gland located?
- Pituitary fossa, inferior of optic chiasm
- Pocket sphenoid bone at the base of the brain
What connects pituitary gland to hypothalamus?
Infundibulum
Why the the two lobes of the Pituitary?
Anterior pituitary glad : adenohypophysis
Posterior pituitary gland : neurohypophysis
What tissue is the anterior pituitary derived from?
A protrusion of ectoderm from the mouth : rathke’s pouch
What tissue is the posterior pituitary derived from?
Neural extension from the neural components of the hypothalamus
What is the hypothalamus stimulated to release by other parts of the CNS.
Hypophysiotropic hormones
What are the hypophysiotropic hormones released by hypothalamus?
- Gonadotropin releasing hormone (GnRH)
- Corticotropin releasing hormone (CRH)
- Thyrotropin releasing hormone (TRH)
- Growth hormone-releasing hormone (GHRH)
Describe the position of the pancreas
- Retroperitoneal
- Posterior to the greater curvature of the stomach
12-15cm long, head lies near the C-portion of the duodenum
Explain the formation of the pancreas in the foetus
At the junction of the foregut and midgut the dorsal and ventral pancreatic ducts are generated and fuse to form the pancreas
Explain the difference between endocrine and exocrine functions of the pancreas
- Exocrine: secrete products into the pancreatic duct, these secretions enter the small intestine. This function begins after birth (e.g. secretion of bile salts, amylase and trypsin
- Endocrine (hormone) functions from 10-15 weeks
Explain the 3 collagenous compartments of the penis
- Two corpus cavernousum
- One corpus spongiousum
What is the scrotum covered by anteriorly ?
Tunica vaginalis
What does the septa of the testis divide into compartments containing seminiferous tubules ?
Tunica albuginea
Where is sperm produced?
Seminiferous tubules
In what month of pregnancy does the testis descend into the scrotum ?
7th
Where is mature spermatozoa found in the seminiferous tubules?
In the centre, in a fluid filled lumen
What does the tubular wall of the seminiferous tubules consist of?
Developing germ cells and supporting Sertoli cells
Where are leydig cells found?
-Small connective tissue spaces between tubules
What do converging seminiferous tubules form?
Rete testis
What epithelium lines the rete testis?
Simple cuboidal epithelium
What epithelium lines the efferent ductles, epididymis, vas deferens, seminal vesicles and bulbourethral glands?
- Pseudostratified columnar epithelium
- The epididymis and vas deferens have stereocilia
What joins the 2 vas deferens to form the ejaculatory duct?
Seminal vesicle
What muscle lines the vas deferens
Smooth muscle
What does the myometrium of uterus consist of?
Thick layer of bundles of smooth muscle in various direction
What epithelium lines the ovary ?
Simple cuboidal epithelium
What does the ovary consist of?
Primordial germ cells surrounded by fibroblast-like stromal cells in the cortex
When do Fallopian tubes open in to?
Abdominal cavity close to the ovaries
What surrounds the opening of each Fallopian rube?
Fimbriae lined with Ciliated epithelium
What epithelium lines the uterus ?
Simple columnar Ciliated epithelium
What epithelium lines the cervix?
Simple columnar epithelium
What epithelium lines the vagina?
Moist stratified squamous epithelium (keratinised at bulbs end)
