1. Surface Anatomy, Vessels, Muscles, and Peritoneum
The Abdomen
Surface Anatomy, Vessels, Muscles, and Peritoneum

2. Abdominopelvic Cavity
Ventral body cavity
Thoracic
Abdominopelvic
Abdominal
Liver
Stomach
Kidneys
Pelvic cavity
Bladder
Some reproductive organs
Rectum

3. Abdominopelvic Cavity
Surrounded by the abdominal walls and pelvic girdle
The two cavities are continuous
Most organs surrounded by a peritoneal cavity
Visceral peritoneum
Parietal peritoneum
Peritoneal cavity
pg 254

4. Abdominal Quadrants 9 regions 4 quadrants Draw “line” through navel
Right upper quadrant
Left upper quadrant
Left lower quadrant
Right lower quadrant
pg 268

5. Surface Anatomy
Anterior abdominal wall extends from costal margin to inferior boundaries:
Iliac crest
Anterior superior iliac spine
Inguinal ligament
Pubic crest
Superior boundary
Diaphragm
Central landmark
Umbilicus
Linea alba (white line)
Tendinous line
Extends from xiphoid process to pubic symphysis
pg 383

6. Muscles Function: Abdominal wall Help contain abdominal organs
Move trunk
Forced breathing
Increase intra-abdominal pressure
Abdominal wall
Anterior (4)
Innervated by intercostal nerves
Continuous with layers of intercostal muscles
Fibers of layers run in different directions for strength
Ends in aponeurosis which contains rectus abdominis muscle
Posterior (3)
pg 276

7. Anterior Abdominal Wall Muscles
External oblique
Origin
Lower 8 ribs
Insertion
Aponeurosis to linea alba, pubic and iliac crest
Function
Flex trunk, compress abdominal wall (together), Rotate trunk (separate sides)
Internal oblique
Lumbar fascia, iliac crest, inguinal ligament
Linea alba, pubic crest, last 3-4 ribs, costal margin
Same for external obliques
pg 276, 277

8. Anterior Abdominal Wall
pg 276
pg 275
Transversus Abdominis
Origin
Inguinal ligament, lumbar fascia, cartilage of last 6 ribs, iliac crest
Insertion
Linea alba, pubic crest
Function
Compress abdominal contents
Rectus Abdominis
Pubic crest, symphysis
Xiphoid process, costal cartilages of ribs 5-7
Flex, rotate trunk, fix and depress ribs, stabilize pelvis, compress abdomen

9. Posterior Abdominal Wall
Iliopsoas
Psoas major
Origin
Lumbar vertebrae, T12
Insertion
Lesser trochanter of femur via iliopsoas tendon
Function
Thigh flexion, trunk flexion, lateral flexion
Innervation
Ventral rami L1-L3
Iliacus
Iliac fossa, ala of sacrum
Thigh flexion, trunk flexion
Femoral nerve (L2 and L3)
Psoas minor – variable (40-60% do not have)
pg 350

10. Posterior Abdominal Wall
Quadratus lumborum
Origin
Iliac crest and lumbar fascia
Insertion
Transverse process of upper lumbar vertebrae, lower margin of rib 12
Function
Flex vertebral column, maintains upright posture, assists in inspiration
Innervation:
T12 and upper lumbar spinal nerves (ventral rami)
pg 350

11. Peritoneum Mesenteries Function: Ventral mesenteries:
Double layer of peritoneum (2 serous membranes fused together)
Extend to the digestive organs from the body wall
Function:
Hold organs in place
Sites of fat storage
Provide a route for vessels and nerves
Ventral mesenteries:
Lesser omentum and Falciform ligament
Dorsal mesenteries:
Greater omentum, Transverse mesocolon, Mesentery proper, and Sigmoid mesocolon
pg 296
pg 324
pg 295, 297

12. Peritoneum Intraperitoneal Retroperitoneal
Organs remain surrounded by peritoneal cavity
Liver, stomach, ileum and jejunum, transverse colon
Retroperitoneal
Some organs lay behind/outside peritoneum
Primarily retroperitoneal
Organs NEVER within the cavity
Kidneys, bladder, ureter
Secondarily retroperitoneal
Organs once suspended within the abdominal cavity by mesentery
Migrate posterior to the peritoneum during the course of embryogenesis to become retroperitoneal
Lack mesenteries
Duodenum, ascending and descending colon, rectum, pancreas

13. Urinary System Kidney (2) Ureter (2) Urinary Bladder Urethra
Purify blood
Ureter (2)
Drains urine from kidney to bladder
Urinary Bladder
Stores urine
Urethra
Drains urine from bladder to outside body
pg 341

14. Kidneys Filter waste from blood Excretion of waste Homeostasis
Water, toxins, urea, uric acid, creatinine, metabolic waste, ions
Excretion of waste
Homeostasis
Acid-base balance
Blood pressure
Plasma volume

15. Kidneys: Gross Anatomy
Lie in retroperitoneal, superior lumbar region
Extend from T11 or T12 to L3
Laterally convex, medially concave
Hilum
Where blood vessels, ureters, and nerves enter and leave kidney
Adrenal gland
On superior portion
Endocrine
Cortisol
Aldosterone
Adrenaline
pg 360

16. Kidney: Gross Anatomy Supportive tissue Renal capsule Adipose capsule
Internal
Supportive tissue
Renal capsule
DCT
Adheres directly to kidney surface
Maintains shape and forms barrier
Adipose capsule
Perirenal fat
Cushions kidney
Keeps kidney in place
Renal fascia
Pararenal fat
pg 357
External

17. Kidney: Internal Gross Anatomy
Cortex
Superficial
Lighter zone
Functional portion
Medulla
Deep
Darker zone
Pyramid shaped
Contains collecting tubules
pg 358

18. Kidney: Gross Anatomy Separated into lobes Blood supply Innervation
Medulla pyramid & associated cortex
Blood supply
Renal artery and vein
Innervation
Branches of renal plexus
pg 358

19. Kidney: Internal Gross Anatomy
Medullary pyramid
Makes up the medulla
Base: against cortex
Apex: inward
Papilla = tip
Drips urine into minor calyx
Calices
Collect urine draining from papillae and empty into renal pelvis
Minor calices
Collect urine from papilla
Surround papilla of pyramids
Empty into major calices
Major calices
Receive urine from several minor calices
Empty into renal pelvis
Renal pelvis
Funnel-shaped
Empties urine into ureter
pg 358

20. Kidney: Microscopic Anatomy
Uriniferous tubules
Produces urine through filtration, reabsorption, and secretion
2 major part:
Nephron
Collecting duct

21. Ureters Carry urine from the kidneys to the bladder
Carry urine from the kidneys to the bladder
Begins superiorly at L2 as a continuation of renal pelvis
Opens into the bladder
Retroperitoneal
Enters the bladder at an oblique angle
This prevents backflow into the ureters
Increased pressure in bladder lead to the distal end of ureter closing
Not only gravity at work here!!
pg 360

22. Ureters: Microscopic Anatomy
Another tubular organ!!
Mucosa
Lamina epithelialis
Transitional epithelium
Stretches when ureters are full
Lamina propria
Muscularis
Inner longitudinal
Outer circular
External longitudinal layer (inferior third)
Function in peristalsis
Adventitia CT
faculty.une.edu

23. Urinary Bladder Stores and expels urine
Posterolateral angle receives the ureter
Inferior angle drains into the urethra
Located:
Inferior to peritoneal cavity
On pelvic floor
Posterior to pubic symphysis
Male:
Anterior to rectum
Female:
Anterior to vagina and uterus
pg 442

24. Urinary Bladder Full bladder expands into abdominal cavity
Empty bladder lies within pelvic cavity
Vasculature:
Internal iliac branches of arteries and veins
Innervation:
Branches of the hypogastric plexus
pg 441

25. Urinary Bladder: Internal Anatomy
Tubular organ!!!!!
Trigone area
3 layers:
Mucosa
Transitional epithelium
Lamina propria
Muscular layer
Detrusor muscle (smooth);
Inner and outer longitudinal, middle circular
Adventitia
Fibrous CT
Parietal peritoneum on superior surface
pg 442

26. Urethra Drains urine from bladder to outside of body
Opens at the external urethral orifice
Female:
Short tube
Male
3 regions
Prostatic urethra
Membranous urethra
Spongy/penile urethra
Also carries ejaculating semen
pg 442

27. Urethra Landmarks Internal urethral sphincter
At bladder/urethral junction
Thickening of detrusor muscle
Involuntary; keeps urethra closed when urine is not being passed
Prevents dribbling!
External urethral sphincter
Surrounds urethra within the urogenital diaphragm
Inhibits voluntary urination until ready
External urethral orifice
Males:
End of the penile urethra
Females:
Anterior to vaginal opening and posterior to clitoris
pg 445

28. Micturition = Urination
Contraction of the detrusor muscle to raise intra-abdominal pressure
Controlled by the brain
Urine accumulation leads to distention of the bladder
Activates stretch receptors
Send sensory impulses to micturition center (MC) in the pons
MC sends signals to parasympathetic neurons
Stimulate detrusor muscle to contract (involuntary)
Internal urinary sphincter opens (also inhibits sympathetic pathways that would prevent urination)

29. Micturition = Urination
Other brain receptors (pons, cerebral cortex) can inhibit urination
Relaxing of the detrusor, keeping external urinary sphincter closed
Voluntary contraction of abdominal wall muscles increases abdominal pressure
Voluntary relaxation of external urethral sphincter

30. Digestive System Alimentary Canal Accessory Organs Mouth Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine
Accessory Organs
Teeth, Tongue
Salivary Glands
Gallbladder
Liver
Pancreas
pg 248

31. Digestive Processes – 6 Steps
Ingestion
Taking food into the mouth
Mechanical digestion
Prepares food for chemical digestion
Chewing, churning, segmentation
Propulsion
Movement of food through GI tract
Swallowing and peristalsis
Chemical digestion
Enzymes break down complex food molecules
Absorption
Digested end products from lumen to blood
Defecation
Elimination of indigestible substances

32. Alimentary Canal Wall ANOTHER tubular organ! Layers: Mucosa Submucosa
Epithelium
Lamina propria (MALT)
Lamina muscularis mucosa
Submucosa
CT with elastic fibers, nerves, vessels
Muscularis
Inner circular
Outer longitudinal
Creates sphincters
Serosa / Adventitia
pg 347

33. Peristalsis vs Segmentation
Propulsion
Adjacent segments of the alimentary canal contract and relax
Moves food distally along the canal
Segmentation
Part of mechanical breakdown
Food-mixing process
Nonadjacent segments of the intestine alternatively contract and relax
Moves food on and back
Mixes rather than propels

34. Innervation Nerve plexuses Occur within wall of alimentary canal
Parasympathetic, Sympathetic, Visceral Sensory fibers
2 types:
Myenteric nerve plexus
Between 2 muscle layers of the tunica muscularis
Controls segmentation and peristalsis
Submucosal nerve plexus
Between submucosa and muscularis mucosa
Signals glands to secrete and LMM to contract

35. Innervation Enteric Nervous System (ENS)
Internal neurons in wall of canal (100 million!!)
Within the above plexuses
Form independent arcs of sensory, intrinsic, and motor neurons
Controls glandular secretion, peristalsis, segmentation
Autonomic Nervous System speeds up or slows activity controlled by enteric system
Allows the CNS to influence it
pg 313

36. Stomach J-shaped, Temporary storage tank Intraperitoneal Regions:
Cardiac
Cardiac orifice
Junction of esophagus
Fundus
Under diaphragm
Body
Large midportion
Pyloric
Ends at the stomach
Pyloric sphincter
Greater curvature
Lesser curvature
pg 299

37. Stomach – Internal Anatomy
Mucosa
Epithelium
Simple columnar
Rugae
Folds that allow for volume changes
Intrinsic glands
Goblet cells
Gastric glands
Parietal cells
Enteroendocrine cells
Chief cells
Submucosa
Muscularis
Oblique layer
Circular layer
Pyloric sphincter
Longitudinal layer
Serosa

38. Stomach Function Storage of chyme Breakdown of food proteins
Food paste
Breakdown of food proteins
Done by pepsin
Protein-digestion under acidic conditions
Absorption of nutrients
H2O, electrolytes
Alcohol, other drugs
Food remains for about 4 hours
Holds from 1.5 to 4 liters

39. Small Intestine Longest portion of GI tract
Site of most enzymatic digestion and absorption of nutrients
Bile: emulsifier (gallbladder, liver)
Enzymes (pancreas)
Undergoes segmentation
Allows for an increase contact with intestinal walls
Peristalsis propels chyme through in about 3 to 6 hours
2.6 to 6 meters long!!

40. Small Intestine Location: Regions:
Location:
From pyloric sphincter to first part of the large intestine
Regions:
Duodenum (5%)
Proximal
Jejunum (almost 40%)
Middle
Ileum (almost 55%)
Distal
pg 300

41. Small Intestine Duodenum Jejunum and ileum Duodenal glands:
C – shaped , short, straight
Mostly retroperitoneal
Receives:
Digestive enzymes from pancreas via main pancreatic duct
Bile from liver via the bile duct
Duodenal glands:
Neutralize acid from stomach
Jejunum and ileum
Highly coiled
Intraperitoneal
Fewer modifications
Hang by mesentery in peritoneal cavity
Mesentery Arcades
Arteries + veins
Nerves
Store fat

42. Small Intestine Internal Anatomy
Intestinal flora
produces vitamin K
Epithelium:
Simple columnar epithelium with many modifications for absorption
Goblet cells
Enteroendocrine cells
Lymph tissue in submucosa
Muscularis externa has 2 layers
Innervation:
Some parasympathetic innervation from vagus
Arterial supply:
Superior mesenteric
Rt (cranial) pancreaticoduodenal
pg 311

43. SI Absorption Modifications
Length
More length, more area for absorption!
Plicae Circulares
Transverse ridges of mucosa
Increase surface area
Force chyme to slow down
Villi
Evagination of plicae circulares
Move chyme and increase contact
Contain lacteals
Remove fat
Microvilli
Further increasing of the surface area
Modifications decrease distally

44. Large Intestine Regions: Cecum Vermiform appendix Colon Rectum
Ascending
Transverse
Descending
Sigmoid
Rectum
Anal Canal
pg 311

45. Large Intestine Overall Functions: Absorbs remaining nutrients
Most material largely digested
Absorbs water and electrolytes
Forms, stores and expels feces from body
Propulsion is slow and weak through LI except for mass peristaltic movements
pg 283

46. LI: Internal Features Intestinal flora
No intestinal villi or modifications for absorption
Many goblet cells
Simple columnar epithelium except lower half of anal canal
Significant lymph tissue in mucosa and submucosa
Muscularis mucosae has 2 layers
Some parasympathetic innervation from vagus

47. Cecum and Vermiform Appendix
Sac-like pouch (blind pouch)
Intraperitoneal
Ileocecal valve
2 raised edges of the mucosa
Prevents reflux of feces from cecum to ileum
Vermiform Appendix
Tubular pouch
Opens into cecum
Contains large masses of lymphoid tissue
assets.aarp.org
pg 302

48. Colon Special Features
Teniae coli
3 Longitudinal strips
Thickenings of longitudinal muscle layer
Maintain muscle tone
Cause LI to pucker into sacs…….
Haustra
Saclike divisions
Epiploic appendages
Fat-filled pouches of visceral peritoneum
Hang from the intestine
pg 279

49. Colon Segments Ascending Transverse Descending Sigmoid Retroperitoneal
Right side of posterior abdominal wall
Makes right angle turn
Right colic / hepatic flexure
Transverse
Intraperitoneal
Extends left across the peritoneal cavity
Bends downward at the spleen
Left colic / splenic flexure
Descending
Left side
Sigmoid
S-shaped
“False pelvis”
pg 311

50. Colon Functions Absorb H2O and electrolytes Some digestion by bacteria
Mass Peristaltic Movements (2-3x day)
Moves through in hours
1.5 meters

51. Rectum Joins with the sigmoid colon Descends into the pelvis
Retroperitoneal
Complete and well-developed longitudinal muscle layer
Rectal valves
3 transverse folds
Prevent feces from being passed along with gas
pg 312

52. Anal Canal Begins where rectum passes through the levator ani muscle
Releases mucus to lubricate feces
Internal anal sphincter
Made of smooth muscle
Involuntary
External anal sphincter
Made of skeletal muscle
Voluntary
Toilet training!!!
Stratified squamous epithelium at lower half
pg 440

53. Defecation Stretching of rectal wall initiates defecation reflex
Mediated by the spinal cord
Parasympathetic reflex signals walls of sigmoid colon and rectum to contract and anal sphincter to relax
Involuntary
If not ready, reflective contraction ends and rectum relaxes
Reflex initiated again until you actually defecate
Contraction of diaphragm, levator ani and abdominal muscles assist
Voluntary

54. Liver Largest gland in the body! Highly vascular Location:
Weighs about 3 pounds
Highly vascular
Location:
Inferior to diaphragm
In right superior part of abdominal cavity
Mostly under rib cage
Functions: (Over 500!)
Produce bile
Pick up glucose
Detoxify poison, drugs
Produce blood proteins
pg 268

55. Liver Gross Anatomy 2 surfaces: Lobes: Diaphragmatic Visceral
pg 317
2 surfaces:
Diaphragmatic
Visceral
Lobes:
Right lobe
Left lobe
Divided by:
Falciform ligament on diaphragmatic surface
Fissure on the visceral surface
Quadrate lobe
Caudate lobe
pg 318

56. Liver – Visceral Surface
Hepatic Vein (into inferior vena cava)
Porta Hepatis
Common Hepatic Artery (from celiac trunk)
Hepatic Portal Vein
Carries nutrient-rich blood from stomach and intestines to liver
Hepatic portal system = 2 capillary beds!
Hepatic Ducts (carry bile)
pg 318

57. Gallbladder Muscular sac Rests in depression of right liver lobe
pg 317
Muscular sac
Rests in depression of right liver lobe
Has many ducts associated with it
Stores and concentrates bile
Emulsification
Produced in liver
Stored in gallbladder
Released into the duodenum
pg 319

58. Gallbladder Mucosa Smooth muscle layer Thick connective tissue
Simple columnar epithelium
Lamina propria
Expandable mucosal folds
Smooth muscle layer
Thick connective tissue
Covered by serosa in places
pg 319

59. Bile Ducts Hepatic duct Cystic duct Common Bile duct
pg 321
pg 323
Hepatic duct
Carries bile from liver
Cystic duct
Joins hepatic duct from liver to form the bile duct
Carries bile from gallbladder
Common Bile duct
Empties into the duodenum

60. Movement of Bile Bile secreted by liver continuously
pg 321
Bile secreted by liver continuously
Hepatopancreatic (Vater) ampulla
common bile + main pancreatic duct meet and enter duodenum
Sphincter of Oddi around it
closed when bile not needed for digestion
Bile then backs up into gallbladder via cystic duct
When needed gallbladder contracts, sphincters open

61. Pancreas Both exocrine and endocrine gland Exocrine Endocrine
pg 320
Both exocrine and endocrine gland
Exocrine
Produce enzymes that digest food
Endocrine
Produce hormones that regulate blood sugar (insulin and glucagon)
Secondarily retroperitoneal (mostly)
Location:
Curve of duodenum
Extends to spleen

62. Pancreatic Ducts Main pancreatic duct Accessory pancreatic duct
Extends length of pancreas
Joins bile duct to form the hepatopancreatic ampulla
Empties into duodenum
Accessory pancreatic duct
Lies in head of pancreas
Drains into the main duct & enters duodenum
pg 321

63. Spleen Largest lymphoid organ Location: Highly vascular Function:
Left superior quadrant of abdominal cavity
Posterior to stomach
Highly vascular
Function:
Removes blood-borne antigens
Removes and destructs aged blood cells
Site of hematopoiesis in fetus
Stores blood platelets
pg 331

64. Arterial Blood Supply to Abdominal Viscera
All branches of Abdominal Aorta
Anastomoses
Left + Middle colic
Left + Right gastric
Left + Right gastroepiploic
Cranial + Caudal pancreaticoduodenal
Remember your zoological roots: YOU MUST KNOW WHAT SUPPLIES WHAT!!

65. Names give hints! Hepato = liver Pancreatico = pancreas
Cystic = gallbladder
Gastro = stomach
Splenic = spleen
Adreno = adrenal gl
Lumbar = lumbar region
Epiploic = membrane-covered
Mesenteric = mesentery
Duodenal = duodenum
Ileo = ileum
Colic = colon
Rectal = rectum