Anatomy Test 3

Abdominal Cavity

Rectus Abdominis Origin

Superior surface of pubis around pubic symphysis

Rectus Abdominis Insertion

Costal cartilages 5-7 + xiphoid process

Rectus Abdominis Action

Depress ribs; flex vertebral column; compress abdomen

Rectus Abdominis Innervation

Intercostal nerves

External Oblique Origin

ribs 5-12

External Oblique Insertion

external oblique aponeuroses extending to linea alba + iliac crest

External Oblique Action

Compress abdomen, depress ribs; flex, laterally flex + rotate vertebral column

External Oblique Innervation

Intercostal nerves, iliohypogastric nerve, ilioinguinal nerves

Internal Oblique Origin

Thoracolumbar fascia, inguinal ligament, iliac crest

Internal Oblique Insertion

Ribs 9-12, costal cartilages 8-10, linea alba, pubis

Internal Oblique Action

Compress abdomen, depress ribs; flex, laterally flex + rotate vertebral column

Internal Oblique Innervation

Intercostal nn., iliohypogastric n., ilioinguinal n.

Transverse Abdominis Origin

Costal cartilage 7-12, iliac crest, thoracolumbar fascia

Transverse Abdominis Insertion

Linea alba + pubis

Transverse Abdominis Action

Compress abdomen

Transverse Abdominis Innervation

Intercostal nn., iliohypogastric n., ilioinguinal n.

Peritoneum

Slippery transparent membrane in abdomen

Intraperitoneal organs

Inside peritoneal cavity/sac

covered on all sides by visceral peritoneum

• ex: stomach, liver, ileum

Retroperitoneal organs

behind peritoneal cavity

outside cavity/sac

covered by visceral peritoneum on the anterior/lateral sides

• ex: kidney, abdominal aorta, ureters

Mesentaries

Fused, double sheets of peritoneum

• provides route for blood vessels, nerves + lymphatics

• Stabilize relative position of attached organs + prevent entanglements of intestines during movement

Stomach

Intraperitoneal

• acts as reservoir

• chemical and mechanical digestion

Mesentaries of Stomach

Greater Omentum

Lesser Omentum

Greater Omentum of Stomach

• large pouch; hang like apron from greater curvature + loop back to the transverse colon

• posterior to anterior abdominal wall + anterior to abdominal viscera

• contains thick layer of adipose tissue

• contains lymph nodes

Lesser Omentum of Stomach

• Lesser curvature of stomach to liver

• Stabilize stomach position

• provide route for blood vessels + other structures entering/exiting the liver

Small Intestines

Duodenum

Jejunum

Ileum

Duodenum

retroperitoneal; pyloric sphincter to jejunum

• major duodenal papilla (opening in wall of small intestines)

Jejunum

Intraperitoneal; duodenum to ileum

Ileum

Intraperitoneal; Jejunum to large intestines

Cecum

Intraperitoneal; First portion of colon; ileocecal valve

Ascending Colon

Retroperitoneal; cecum to hepatic/right colic flexure

Transverse Colon

2/3 intraperitoneal, 1/3 retroperitoneal; splenic/left colic flexure

Descending Colon

retroperitoneal

Sigmoid Colon

Intraperitoneal; sigmoid flexure

Rectum

intraperitoneal; storage, expandable

Taenia Coli

• line on large intestines

• 3 longitudinal bands of smooth muscle

Haustra

• wall of colon forms a series of pouches

• permits distension/elongation

Mesenteries of Colon

Transverse mesocolon

Sigmoid mesocolon

Omental Appendices

tear-drop shaped sacs of fat

Liver

intraperitoneal

Gallbladder

inferior side of liver

• store + concentrate bile —> hollow pear-shape

Pancreas

exocrine and endocrine functions

Exocrine: pancreatic juice (breaks down proteins)

Endocrine: creates insulin (blood sugar)

Spleen

Intraperitoneal

Functions:

• immunoresponses

• remove + recycle old blood cells

• recycle iron

Kidney

retroperitoneal

perinephric fat: layer of fat that surrounds kidneys

Suprarenal (Adrenal) Glands

Retroperitoneal

endocrine

cortex secretes hormones that retain sodium and water

medulla secretes hormones for fight-or-flight response

Arterial supply from abdominal aorta

3 unpaired arteries from abdominal aorta

• celiac trunk

• Superior mesentery artery

• Inferior mesentery artery

Celiac Trunk

Common Hepatic a. - liver, gallbladder, stomach, duodenal area

Left Gastric a. - stomach, inferior esophagus

Splenic a. - spleen, pancreas, stomach

Superior Mesenteric Artery

Intestinal aa. - jejunum + ileum

Ileocolic a. - ileum, cecum, ascending colon

Right colic a. - ascending colon

Middle colic a. - transverse colon

Inferior Mesenteric Artery

Left colic a. - descending colon

Sigmoid a. - sigmoid colon, descending colon

Rectal aa. - rectum

Abdominal Aorta

5 paired arteries:

• inferior phrenic aa

• suprarenal aa

• renal aa

• gonadal aa

• lumbar aa

Inferior Phrenic aa.

supply blood to inferior diaphram + inferior/distal esophagus

Gonadal aa.

Testicular aa. - testes + scrotum

Ovarian aa. - ovaries + uterine tubes + uterus

Lumbar aa.

supply vertebrae, spinal cord, abdominal wall

Lumbar vv.

drains lumbar portion of abdomen

Gonadal vv.

drain ovaries + testes

Right gonadal —> Inferior Vena Cava

Left gonadal —> left renal vein —> Inferior Vena Cava

Hepatic vv.

Drain from liver to Inferior Vena Cava

Renal vv.

Drain kidneys (right side is shorter than left side)

inferior phrenic vv

Drain inferior diaphragm

Right: inferior vena cava

Left: left renal vein → Inferior Vena Cava

Veins that contribute to the Hepatic Portal Vein

1. Splenic v.

2. Superior mesenteric v.

3. Inferior mesenteric v. (goes to splenic v)

Splenic v.

drain stomach, spleen, and pancreas

Superior mesenteric v.

Drain stomach, small intestines, and colon

Inferior mesenteric v.

Drain inferior/distal portion of large intestine

Scrotum

Pouch of skin, suspended inferior to perineum, anterior to anus

Functions: internally divided into 2 compartments

• 1 for each testis

Corpus Cavernosum (paired)

Anterior surface

Hemotumescent

Corpus Spongiosum

Surrounds spongy urethra

Hemotumescent

Distal end: expanded → glans penis

Mons Pubis

Fat over pubic symphysis

Pelvic Viscera

All organs (except uterus) are considered retroperitoneal

Bladder

Stores urine - pear-shaped —> expands as urine increases

Spermatic Cord

Ductus (vas) Deferens

Testicular a.

(heat transfer to cool testis = countercurrent sink system)

Testicular v.

• pampiniform plexus → leads back to the testicular vein

Testes

Seminiferous Tubules

• produce sperm

• produce testosterone

Epididymis

• Moniter/adjust fluid composition that sperm lives in

• stores sperm

• facilitates maturation

• recycle damaged/unused sperm

Seminal vesicles

• dumps into ejaculatory duct w/ductus deferens

• contributes to production of semen

Ovaries

• Small, paired organs - flatten oval

• located near lateral walls of pelvis

• responsible for producing ova and secreting hormones

Uterine tubes

Path for ovum to reach uterus

3 walls of Uterus

1. Endometrium

2. Myometrium

3. Perimetrium

Endometrium

inner mucous coat

• thickness varies throughout cycle

• implantation of the blastocyst or layer is shed

Myometrium

Middle layer (smooth muscle)

• greatly thins during pregnancy

• contractions of this muscle layer help to deliver fetus/infant

Perimetrium

outer layer (peritoneum)

• serous layer

Vagina

• muscular canal 3.5-4’’ long (birth canal)

• located posterior to bladder

Rectum

• Retroperitoneal

• last 15 cm of gastro tract

• last portion is anal canal

Anal Canal

• End of the anus

• Circular muscle layer in this region forms internal anal sphincter (involuntary)

• External anal sphincter encircles distal portion of the anal canal (voluntary)

Trigon of the Bladder

smooth transitional epithelium

Is a landmark in the bladder with triangular shape

Path for the ovum to reach the uterus:

Ovary → Fimbriae → Infundibulum → ampulla → Isthmus → uterine part

Connects Gallbladder to Duodenum

Major Duodenal Papilla

The Common Bile Duct and Pancreatic Duct combine to form what?

Hepatopancreatic Ampulla

If the superior mesenteric artery was compromised, what organs would potentially lose arterial blood flow?

Jejunum, ileum, cecum, ascending colon, and Transverse colon. This is because the superior mesenteric artery is related to the intestinal aa., ileocolic a., right colic a., and middle colic a.

What duct would need to be ligated in order to perform a gallbladder removal?

Cystic Duct

If the left renal vein was damaged, what structures (not veins) would not be able to return blood to the inferior vena cava?

The left inferior phrenic v. and left gonadal v. contribute to the left renal vein which means, the left kidney, left ovary/testis, and left diaphragm would not be able to return blood.

What structures are most likely to be affected if someone has an abdominal infection that spread retroperitoneally?

Suprarenal (adrenal) Glands
Aorta (inferior vena cava)
Duodenum

Pancreas

Ureters
Colon (ascending and descending)
Kidneys
Esophagus
Rectum

As filtrate leaves the renal pyramids, describe the path the urine would use to leave the kidney.

renal pyramid → minor calyx → major calyx → renal pelvis → ureters → urinary bladder

What structure helps to stabilize the relative position of the stomach by connecting to the liver?

Lesser Omentum

What structure helps keep the coils of the jejunum and ileum in relative order?

Mesentery Proper

Why might an enlarged prostate lead to a weak or interrupted flow of urine?

The prostate would swell inwards and impinge the prostatic urethra

What structure is in danger if the inguinal canal is injured?

Female: round ligament of the uterus

Male: spermatic cord

Why might a pregnant person have to urinate more frequently as the pregnancy progresses?

The uterus sits posterior and superior to the bladder, so as the uterus expands to support the fetus, the bladder is pushed on, making it less able to expand/hold urine.