Organs of abdomen

organs of abdomen

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How to Calculate Your Grade
You have completed 500 out of 700 total points
Add together:
Lecture exam 1
Lecture exam 2
Lab exam 1
Lab exam 2
Average of your 7 best quizzes (drop lowest)
Divide by 500
REMEMBER:
You must have at least a “C” = 68 in both lab and
lecture separately to pass course

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How to Calculate the Number of
points you need to pass
You need a total of 476 out of 700 points to get a C
Take the total number of points you just calculated
(the sum of 4 exams and quiz average) and subtract
it from 476
The number you have is the total number of points
you need
If you divide that number by 2, you will see the
approximate grade you’ll need on lab exam 3 and
lecture exam 3.
REMEMBER: the rules from previous page apply
Have to have at least C in lecture and lab separately

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Organs of the Abdomen
Systems: Urinary and Digestive

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Urinary System
Kidneys
Purify blood
Ureters
Drain urine from kidney
to bladder
Urinary Bladder
Store urine
Urethra
Drain urine from
bladder to outside body
pg 5

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Kidneys: major excretory organs
Remove toxins, metabolic waste, excess
H
2
O, ions
Urea, uric acid, creatinin
Regulates volume + makeup of blood
Maintains balance between
Salts and water
Acids and bases

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Kidneys: Gross Anatomy
Located superior
lumbar region
Posterior abdominal
wall (T12-L3)
Retroperitoneal
Hilus
Adrenal Gland:
superomedial to kidney
Renal Artery + Vein
Innervation: branches of
renal plexus
pg 648

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Kidneys: Gross Anatomy
Renal Capsule
Layer of tough CT
Maintains shape
Prevents spread of
infection
Adipose Capsule
External to renal cap
Perirenal fat
Surrounded by fascia
Keeps in place, cushions
Pararenal Fat
External to adipose cap
Keeps in place, cushions
pg 649

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Kidney: Internal Anatomy
Cortex
Superficial
Light, granular
Part of functional unit
Medulla
Deep layer
Darker
Pyramid-cone shape
Contain collecting
tubule collect urine
Pg 650

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Kidney: Internal Anatomy
Medullary Pyramid
Base: against cortex
Apex: inward
Papilla = tip
Drips urine into minor calyx
Minor Calyx (calices)
Cup-shaped divisions of
major calices
Surround papilla of pyramid
Major Calyx (calices)
Larger cup-shaped
branches of renal pelvis
Renal Pelvis
Flat expansion of ureter
Collects urine
Pg 650

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Kidney: Microscopic Anatomy
Functional Unit
Uriniferous Tubule
Nephron
Collecting tubule
Waste is filtered out
Waste products formed
Located in lobes of
kidneys
pg 652

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Ureters
Slender tubes transport
urine
Run from kidneys to
bladder
Retroperitoneal
Continuation of renal
pelvis
Enters bladder at oblique
angle to prevent backflow
Increased pressure in
bladder closes distal end
of ureter
pg 648

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Ureters: 3 Layers
External: Adventitia
CT
Middle: Muscularis
Smooth Muscle
Inner Longitudinal
Outer Circular
External longitudinal (on
distal third)
Peristalsis
Inner: Mucosa
Transitional epithelium

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Bladder
Muscular sac store and
expel urine
Location
On pelvic floor
Posterior
 Pubic symphysis
Anterior
Males = rectum
Females = vagina, uterus
Collapses + Expands
Full  into abdominal cav
Emptystays in pelvic cav
Supplied by branches of
internal iliac arteries +
veins
Innervated = branches of
hypogastric plexus
pg 648

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Bladder: Internal Anatomy
3 Layers
Mucosa = transitional epithelium & lamina propria
Detrusor Muscle: smooth muscle
Inner/Outer longitudinal, Middle circular
Fibrous Adventitia = CT
Parietal peritoneum on superior surface instead
trigone
pg 662

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Urethra
Drains urine from bladder to outside
Female = short tube
Males = long tube
Prostatic, Membranous, Spongy (penile) portions
Also carries semen
Internal Urethral Sphincter
Between bladder + urethra
Thickening of detrusor (smooth muscle)
External Urethral Sphincter
Within urogenital diaphragm
Skeletal muscle = voluntary control urination
External Urethral Orifice
Males = end of penile urethra
Females = anterior to vaginal opening, posterior to clitoris

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Urethra: Female vs. Male
pg 662

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Micturition = Urination
Emptying bladder
Stretch receptors in bladder respond when bladder
full
Parasympathetic signals detrusor muscle to
contract and internal urinary sphincter to open (also
inhibits sympathetic pathways that would prevent
urination)
Other brain receptors can inhibit urination by
relaxing detrusor, and keep external urinary
sphincter closed
Voluntary contraction of abdominal wall muscles
increases abdominal pressure
Voluntary relaxation of external urethral sphincter
See pg 663

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Digestion System
Alimentary Canal
Mouth
Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine
Accessory Organs
Teeth, Tongue
Salivary Glands
Gallbladder
Liver
Pancreaspg 5

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Food Processing Activities
Ingestion: taking food into mouth
Propulsion: food moves through gut
Swallowing + Peristalsis
Mechanical Digestion: breakdown of food
Chewing, Churning, Segmentation
Chemical Digestion: chemical breakdown
Enzymes
Absorption: Digestive end products into
blood
Defecation: Removal of waste products

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Alimentary Canal Wall
Internal = Mucosa + Submucosa
Epithelium
Lamina propria:
contains MALT: mucosa-associated lymphoid tissue
Muscularis mucosae
Submucosa = CT w/elastic fibers, nerves, vessels
Middle = Muscularis Externa
Inner circular layer
Outer longitudinal layer
Creates sphincters
Outer = Serosa or Adventitia

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Innervation of Alimentary Canal
2 Plexuses: Myenteric & Submucosal
Parasympathetic, Sympathetic, Visceral
Sensory fibers
Enteric Nervous System
100 million neurons in walls of alimentary
canal = internal system
Within above plexuses
Independent reflex arcs
Controls glandular secretion, peristalsis,
segmentation
Autonomic Nervous System speeds up or
slows activity controlled by enteric system

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Stomach
“J” shape
Cardiac Region
Junction esophagus
Cardiac sphincter
(Gastroesophageal)
 Fundus (“dome”)
Under diaphragm
Body
Large, middle part
Pylorus
Distal portion
Pyloric sphincter
Greater Curvature
Lesser Curvature
Pg 624

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Internal Anatomy of Stomach
Mucosa
Rugae: mucosal folds
allow expansion
Many intrinsic glands
Goblet cells
Gastric glands
Typical Submucosa
Muscularis externa
Oblique layer
Circular layer
Pyloric sphincter
Longitudinal layer
Serosa
pg 624

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Function of Stomach
Temporary storage of chyme
Breakdown begins
Churn, segmentation
Pepsin proteins
Absorption
H
2
O, electrolytes
Alcohol, other drugs
Stays about 4 hours
Hold from1.5-4 liters

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Small Intestine: Parts + Functions
Parts
Duodenum = proximal (5%)
Jejunum = middle (~40%)
Ileum = distal (~55%)
Majority of enzymatic digestion
Bile: emulsifier (gallbladder, liver)
Enzymes (pancreas)
Almost all nutrient absorption
Segmentation
Moves chyme around to increase contact with
intestine walls
Food takes about 3-6 hours to move through
2.7- 6 meters

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Small Intestine: Internal Features
Intestinal flora: produce vitamin K
Simple columnar epithelium w/many
modifications for absorption
Lymph tissue in submucosa
Muscularis externa has 2 layers
Some parasympathetic innervation from
vagus
Arterial supply:
Superior mesenteric
 Rt (cranial) pancreaticoduodenal

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Small Intestine: Modifications of
epithelium for absorption
Length
 Increase surface area
Plicae circularis
Transverse ridges of mucosa
Increase surface area
Slow movement of chyme
Villi
Move chyme, increase contact
Contain lacteals: remove fat
Microvilli:
 Increase surface area
Modifications decrease distally
pg 629

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Small Intestine
Duodenum:
short, straight
Mostly retroperitoneal
Jejunum & Ileum:
 highly coiled
Fewer modifications
Hang by mesentery in
peritoneal cavity
Mesentery Arcades
Arteries + veins
Nerves
Store fat
Pg 614

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Large Intestine
Cecum
Vermiform appendix
Colon
Ascending
Transverse
Descending
Sigmoid
Rectum
Anal Canal
pg 631

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Large Intestine
Functions:
Absorb water and electrolytes
Form, store and expel feces from body
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 & submucosa
Muscularis mucosae has 2 layers
Some parasympathetic innervation from vagus

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Colon: External Features
Taeniae coli
3 longitudinal strips
thickening of
longitudinal muscle
maintain muscle tone
create haustra
Haustra
saclike divisions
Epiploic Appendages
fat-filled pouches
significance unknown
pg 631

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Cecum + Vermiform Appendix
Cecum
sac-like, blind pouch
Ileocecal valve
raised edges of mucosa
prevents feces going
back into ileum
Vermiform Appendix
same layers
blind tube opens into
cecum
masses of lymph tissue
pg 631

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Colon Ascending colon
Right side
Hepatic flexure
(= right colic
flexure)
Transverse colon
Across cavity
Descending colon
Left side
Splenic flexure
(= left colic flexure
)
Sigmoid colon
Enters pelvis
“S” shape
pg 631

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Colon: Function
Absorb H
2O and electrolytes
Some digestion by bacteria
Mass Peristaltic Movements (2-3x day)
Moves through in 12-24 hours
1.5 meters

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Rectum +
Anal Canal
Rectum
descends into pelvis
no teniae coli
longitudinal muscle layer
complete
rectal valves
Anal Canal
passes through levator ani
muscle
releases mucus to lubricate
feces
Internal anal sphincter
involuntary, smooth m.
External anal sphincter
voluntary, skeletal m.
Stratified squamosal
epithelium at lower half
pg 632

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Defecation Reflex
Stretching of rectum wall initiates reflex
Spinal cord - parasympathetic signals
sigmoid colon + rectum to contract +
anal sphincter to relax (involuntary)
If not ready-reflex ends- rectum relaxes
Reflex initiated again until you go!
Contraction of abdominal muscles,
levator ani + diaphragm assists
defecation (voluntary)

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Liver Largest gland (3 lbs)
Location
Upper Right Quadrant
Mostly under ribcage
Highly vascular
Some functions
produce bile
pick up glucose
detoxify poison, drugs
make blood proteins
many others
pg 610
pg 635

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Liver: External Features
pg 635
Diaphragmatic surface
Right lobe (larger)
Left lobe
Falciform ligament
Fissure between
Visceral surface
Quadrate lobe
Caudate lobe
Both part of left lobe

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Liver:
Visceral
Surface
Hepatic Vein (into inferior vena cava)
Porta Hepatis
Hepatic Artery (from abdominal aorta )
Hepatic Portal Vein
Carries nutrient-rich blood from stomach + intestines to
liver
Portal system = 2 capillary beds!
Hepatic Ducts (carry bile)
pg 636

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Gallbladder
Muscular sac
Between right +
quadrate liver lobes
Bile is stored +
concentrated
Bile: breaks down fats
= emulsification
Bile
Produced by liver
Stored in gallbladder
pg 610

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Gallbladder continued
Mucosa & lamina propria
Simple columnar epithelium
Expandable mucosal folds
Smooth muscle layer
Thick connective tissue
Covered by serosa in places

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Bile Ducts
Cystic duct
carries bile from gallbladder
Hepatic duct
carries bile from liver
Common Bile duct
joins cystic and hepatic
carries bile into duodenum pg 628

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Movement
of Bile
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
pg 628

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Pancreas Retroperitoneal
Gland
Exocrine
digestive enzymes
Endocrine
hormone insulin
hormone glucagon
Location
curve of duodenum
extends to spleen
pg 639

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Ducts of Pancreas
Main Pancreatic duct
joins common bile
duct
enters duodenum
Hepatopancreatic
(Vater) ampulla
Accessory
Pancreatic duct
enters duodenum in
other location
pg 628

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Spleen
Largest lymph organ
Highly vascular
Function
remove blood-borne
antigens (immune)
remove and destroy
old/damaged blood
cells
stores blood platelets
In fetus: site of
hematopoiesis
pg 639

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Arterial Blood Supply to
Abdominal Viscera
All branches of Abdominal Aorta
Anastomoses
Left + Middle colic
Left + Right gastric
Left + Right gastroepiploic
Cranial + Caudal pancreaticoduodenal
Deep Iliac Circumflex + Adrenolumbar
STUDY HAND OUT! MUST KNOW
WHAT SUPPLIES WHAT!!

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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