The Abdomen

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The Abdomen

• Human Anatomy
• BIOL 1010

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Some Landmarks

• UMBILICUS
• - Belly Button
• COSTAL MARGIN
• - Midaxillary at rib 10
• ILIAC CREST
• - ½ of the dimple formed inferior to the
  costal margin. This forms the top of the pelvic
  girdle

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• ILIAC TUBERCLE
• - level of the 5th lumber vertebra.
  Inferior to the iliac crest.
• ANTERIOR SUPERIOR ILIAC SPINE
• - ASIS
• PUBIC TUBERCLE
• - lateral to the pubic symphysis

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• RECTUS ABDOMINIS MUSCLE
• - 4 segments on each side
• - obvious during sit-ups (lateral margin)
• - segments separated by tendinous
  intersections
• a. Level at umbilicus
• b. Inferior to the xiphoid
• c. Midway between a and b

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• McBERNEYS POINT
• - on the right side
• - 1/3 the distance moving in a
  superior-medial direction from the ASIS to the
  umbilicus. This is where incisions are made to
  remove the appendix.
• LINEA ALBA
• - straight down the midline.
• - color white and is connective tissue.

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• INGUINAL LIGAMENT
• - passes from the ASIS to the pubic tubercle
  and its inferior border is actually formed by
  folding under itself.

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• The rectus abdominis muscle lies within the
  aponeurosis of the abdominal muscles.
• The linea alba is the union of all the
  aponeuroses.
• There are three layers of abdominal musculature
• a. External oblique
• b. Internal oblique
• c. Tranversus abdominis

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• The fibers of the external and internal oblique
  muscles are perpendicular to each other.
• External oblique muscle fibers run superolateral
  from their tendinous insertion.
• The internal oblique muscle fibers run
  inferolateral.

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• Deep to these muscles lie the transverse
  abdominis muscle. In the human, these fibers are
  transverse.
• The rectus abdominis muscle run superior to
  inferior. It attaches in some places to the
  aponeurosis of the internal oblique.

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• External Oblique
• origin lower 8 ribs
• inserts xiphoid process, linea alba, pubic
  symphysis, pubic tubercle, and iliac crest
• Internal Oblique
• origin lumbar fascia, iliac crest,
  inguinal ligament
• inserts lower 3 ribs and costal cartilage,
  xiphoid, linea alba, pubic symphysis

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• Transverse Abdominis
• origin 6 lower costal cartilages, lumbar
  fascia, iliac crest.
• inserts xiphoid, linea alba, pubic
  symphysis
• ALL OF THESE MUSCLES COMPRESS THE ABDOMINAL
  CONTENTS, SUPPORT VISCERA, and ROTATE THE TRUNK.

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• On the dorsal wall of the abdomen, we find the
  PSOAS MAJOR and PSOAS MINOR muscles.
• These originate on the transverse process of
  T12-L5 and insert on the lesser trochanter of the
  femur.
• They flex the thigh and the trunk

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• The QUADRATUS LUMBORUM originates on the iliac
  crest and transverse processes of L5.
• It inserts on rib 12 and L1-4.
• Its action is to depress the rib cage and act as
  a lateral flexor.

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• The ILIACUS MUSCLE originates on the iliac fossa
  and inserts on the lesser trochanter of the
  femur.
• It forms a muscle sheet with the psoas. This is
  commonly called the iliopsoas.
• It flexes the thigh and the trunk.
• Filet Mignon is the psoas major.

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Muscles of the Anterior Abdominal Wall
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The Inguinal Region

• The inguinal ligament is formed by the
  aponeurosis of the abdominal muscles. This is
  attached at the ASIS and pubic tubercle.
• Anything going from the abdominal cavity to the
  testes must go through this ligament.
• The area of the ligament that allows these
  structures to pass through is called the INGUINAL
  CANAL.

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• The inguinal canal is composed of an internal and
  external INGUINAL RING.
• The internal inguinal ring is displaced laterally
  from the external ring.
• An empty space connects these rings and forms the
  INGUINAL CANAL. Blood vessels, nerves,
  lymphatics, and the vas deferens to the testes
  fill this canal.
• Part of the viscera can pass through the canal
  and become a HERNIA. If the herniated organ
  becomes stuck or strangled, blood supply is
  compromised and death to the tissue can result.

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Abdominal Quadrants

• The abdominal cavity can be divided into 9 areas
  called quadrants.
• The quadrants are separated by imaginary lines.
• The lines are
• a. Subcostal plane drawn transversely
  at the level of L3 vertebra.
• b. Transpyloric Line (TPL)
• c. Intertubercular Line drawn through
  the iliac tubercle.

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The Nine Abdominal Quadrants/Regions
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• d. 2 vertical lines from a point on the
  superior margin of the diaphragm at the level of
  midclavicular to the inguinal ligament.
• The boundaries of the abdomen
• superior diaphragm
• inferior pelvic inlet (beginning of pelvic
  cavity
• anterior abdominal muscles
• posterior lumbar vertebrae, diaphragm, rib
  12
• lateral some ribs, muscles, diaphragm,
  iliac fossa

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The Transpyloric Line

• At the level of rib 9 at the lateral margin of
  the rectus abdominis muscle.
• It crosses the S1 vertebra.
• It lies superior to the subcostal line and passes
  through the right and left hypochondral and
  epigastric spaces.
• The duodenal-jejunal junction, kidneys, liver,
  gallbladder, stomach, pancreas, spleen, and both
  colic flexures lie on or touch the TPL.

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The Peritoneum

• A serous membrane that produces fluid that
  reduces friction.
• It lines and covers the walls and organs of the
  abdomen.
• 2 layers
• parietal attached to the body wall
• visceral attached to the organs

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• Sometimes the peritoneum connects to organs. It
  is then called a ligament.
• The peritoneal cavity is a POTENTIAL SPACE.
• Most organs in the abdomen are in the peritoneal
  cavity. There are some structures which remain
  entirely outside the cavity. These are called
  RETROPERITONEAL as they are behind the peritoneum.

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• There are actually 2 peritoneal cavities. They
  communicate through the EPIPLOIC FORAMEN.
• It is found on the right side, superior to the
  duodenum and is adjacent to the common bile duct.
• The GREATER OMENTUM is made of two layers that
  form the bursa

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• The GREATER OMENTUM is made of two layers that
  form the mutual bursa in the lesser peritoneal
  cavity.
• It completely covers the small intestine.
• It is filled with fat and it helps lubricate the
  organs in the peritoneum.
• It produces MACROPHAGES which help keep the
  cavity clean of debris.

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• The MESENTERIC LIGAMENT (mesentery) is a double
  folded layer of connective tissue that holds the
  veins, arteries, nerves, and lymphatics of the
  peritoneum.
• It also prevents the intestine from forming knots
  within its folds.
• From the mesentery, two ligaments arise
• 1. mesocolic
• 2. mesovarian

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The Urinary System

• The KIDNEYS are found approximately 2 inches from
  the vertebral column (3 fingerbreadths lateral).
• The right kidney is LOWER than the left.
• The superior edge of the left kidney is at T12.
  The inferior edge of the right is at L3.
• They are moveable during breathing. They move
  approximately I inch in either direction.

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• The URETER enters the bladder from below. Which
  means that the bladder fills from the bottom.
• The URETHRA is central. It is approx. 1.5 inches
  long in females and 8 inches long in males. This
  fact is important because the length of a foley
  catheter differs in the sexes.

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• A coronal section (frontal section) of the kidney
  will reveal the junction of the ureter and kidney
  form a funnel.
• This area is called the RENAL PELVIS.
• The renal pelvis contains the COLLECTING
  TUBULES from the RENAL MEDULLA.

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• The outer portion of the kidney is the RENAL
  CORTEX. In humans, the renal cortex extends
  between the RENAL PYRAMIDS.
• Each pyramid branches into smaller funnels called
  CALYX. Each calyx receives part of the medulla.
  Each calyx has its own pyramid.

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The Right Kidney and Adrenal Gland
CAT ?
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Renal capsule
Minor calyx
Major calyx
Renal artery
Renal vein
Renal pelvis
ureter
Renal pyramid
Renal medulla
Renal cortex
Renal column
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• There are approximately 8-10 calyces and a
  pyramid for each one in each human kidney.
• The functional unit of the kidney is the NEPHRON.
  There are about 2.5 million nephrons in each
  kidney.
• The ADRENAL GLANDS (suprarenal glands) are
  endocrine glands found on the superior portion of
  each kidney. They secrete EPINEPHRINE and
  NOREPINEPHRINE.

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Suprarenal glands
Renal vessels
urachus
ureter
Trigone of bladder
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What is in Urine?
Urea derived from the breakdown of amino acids
(building blocks of proteins). Uric Acid
results from the turnover of nucleic
acids. Creatinine formed by the breakdown of
creatine phosphate (found in muscle)
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The Digestive System

• Function physically and chemically breakdown
  food products so that they can be absorbed and
  transported to cells.
• CARBOHYDRATES are the major source of biochemical
  energy. They include sugars and starches. These
  are eventually broken down into MONOSACCHARIDES
  (simple sugars)

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• PROTEINS are broken down to amino acids. AMINO
  ACIDS are the chemical building blocks of
  proteins. Proteins are necessary parts of cell
  membranes and nucleic acids (DNA and RNA).
• LIPIDS are broken down to fatty acids and
  glycerol. Lipids are very large molecules and
  cannot be directly absorbed. They are broken down
  by ENZYMES which are organic CATALYSTS. They are
  very specific for each chemical reaction and the
  function to speed up the reaction.

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• The name of an enzyme usually end in -ase and
  can give a clue as to its function.
• For example, Lipase is an enzyme that catalyzes
  the breakdown of lipids (fats and oils)

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Chewing (Mastication)

• Helps the digestive process by
• a. Mixes food with digestive enzymes in
  saliva.
• b. Increases surfaces area of food
• c. Makes moving the food easier

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Saliva

• Contains PTYALIN or SALIVARY AMYLASE. These are
  enzymes that break down starches. These enzymes
  are only active under certain pH conditions.
• The pH of the mouth is about 7.2 (slightly
  alkaline as 7 directly in the middle of the scale)

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• When the swallowed food reaches the stomach, the
  pH drops to 3 (very acidic). The ptyalin is no
  longer active at that pH.
• Once food is swallowed, smooth muscle in the
  esophagus carries the bolus by PERISTALSIS.

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Histology of the Digestive System

• All alimentary canal organs have the same 4
  layers.
• Mucosa (innermost layer)
• Submucosa (CT containing neurovascular bundles)
• Muscularis Externa (2 layers of smooth muscle)
• Serosa (outermost layer, visceral peritoneum)

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• Once food enters the esophagus, peristalsis is
  automatic. In fact, food can successfully reach
  the stomach while standing on your hands.
• The bolus enters the stomach by passing through
  the GASTROESOPHAGEAL SPHINCTER. It is held shut
  by contraction of muscle.

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esophagus
Gastroesophageal sphincter
Fundus
Pylorus
Body
Pyloric shpincter
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• The LESSER CURVATURE of the stomach is anchored
  to the liver with the LESSER OMENTUM. It cannot
  move.
• The esophagus and duodenal ends are anchored. As
  food fills the stomach, it can sag on the left
  side.

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• The walls of the stomach have 3 muscle layers
• These muscles do not contract together-they
  contract out of sync. This enables the muscles
  to mix and churn the food in the body of the
  stomach.
• The mixing is with water, hydrochloric acid
  (produced in the stomach), and pepsin. This
  mixture is known as CHYME.

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• The release of the chyme is regulated by the
  pyloric sphincter.
• The stomach also has longitudinal folds within
  the lumen. These folds, called RUGAE, increase
  the surface area of the stomach.

Endoscopy showing ruguae
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Small Intestine

• 3 parts
• 1. Duodenum
• - 10 inches long
• 2. Jejunum
• - 8 feet long
• 3. Ileum
• - 11 feet long

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• The small intestine produces 7 enzymes. There
  are a total of 17 enzymes that are dumped into
  the duodenum for digestion.
• The small intestine is the area where most
  digestion occurs.
• It is also the place where 74 of the absorption
  of nutrients occur.

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• The absorptive area is increased by
• 1. circular folds called PLICAE
  CIRCULARIS.
• 2. Microscopic VILLI
• 3. MICROVILLI
• These structures increase the surface area of the
  small intestine by 600x

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• Within the plicae circularis are arteries,
  capillaries, and veins. The veins drain into the
  HEPATIC PORTAL SYSTEM which ultimately drain into
  the liver and INFERIOR VENA CAVA.
• There is also lymphatic drainage via LACTEALS
  which drain into the CISTERNA CHYLI. These drain
  into the THORACIC DUCT.

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• SEGMENTAL PERISTLASIS occurs in the small
  intestine. This segmenting results in a sausage
  appearing structure.

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• The ileocecal valve (sphincter) regulates flow
  into to large intestine. It also prevents
  backflow from the large intestine into the small
  intestine.

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Sources of Intestinal Secretions
Esophagus
Stomach
Cystic Duct Hepatic Ducts
Spleen
Common Bile Duct
Gall Bladder
pancreas
Jejunum
villi
Duodenum
microvilli
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The Large Intestine

• 5 feet long
• The CECUM extends as a 2.5 inch blind sac
  caudally from the sphincter.
• Off the cecum is the APPENDIX. There is
  currently no purpose for the appendix. Some
  research is pointing toward an immune function.

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• From the cecum is the ASCENDING COLON (5 inches).
  It is retroperitoneal.
• The RIGHT COLIC FLEXURE leads to the TRANSVERSE
  COLON (15 inches).
• The LEFT COLIC FLEXURE leads to the DESCENDING
  COLON (10 inches) and it is also retroperitoneal.

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• The descending colon leads to the SIGMOID COLON.
  The name change occurs at the SIGMOID FLEXURE.
• The RECTUM (5 inches) leads to the ANAL CANAL (7
  inches).
• The final sphincter in the tract is the SPHINCTER
  ANI.
• The sigmoid and rectum are also retroperitoneal.

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• The transverse colon hands on a piece of the
  MESOCOLIC LIGAMENT.
• It hangs into the umbilical region.
• The longitudinal bands of muscle in the colon are
  three bands that do not completely surround the
  structure.
• The only part of the large intestine that have
  complete muscle coverage is the rectum.

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Parotid Gland
Liver
esophagus
Gastroesophageal sphincter
Fundus of Stomach
pancreas
Gall bladder
Pylorus of stomach
cecum
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• The muscles act like a drawstring that contract
  the colon into little pouches. These pouches are
  called HAUSTRA.
• The material that reaches the colon is undigested
  and/or undigestable.
• Bacteria live in the colon. These are important
  for the synthesis of Vit. B12 and K. Other
  bacteria are responsible for destroying the bad
  bacteria.
• E. coli is an example

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• The sphincter ani is an involuntary smooth
  muscle.
• The DEFECATION REFLEX which is kept in control by
  the sigmoid flexure and peristaltic activity.
• When peristalsis occurs the sphincter ani
  relaxes. An EXTERNAL SPHINCTER (skeletal muscle)
  can oppose the sphincter ani. This allows you to
  hold it in until you find a bathroom!
• The first part and part of the second third of
  the esophagus are also made of skeletal muscle.
  The rest of the GI tract is smooth muscle.

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Transverse Colon
Tenia coli
Haustra
Descending Colon
Terminal Ileum
Ascending colon
Sigmoid colon
cecum
rectum
appendix
Anal Canal
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Types of Hernia
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A for TRUE B for FALSE

• Haustra are found on the small intestine.
• The pH of the mouth is 7.2 which is slightly
  acidic.
• The epigastric region of the abdomen is located
  directly superior to the umbilical region.
• The transverse colon is retroperitoneal.
• McBerneys point is located on the left side
  where the appendix is usually removed.

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• A full bladder is approximately 300 cc of urine.
• The minor calyx drains into the renal pelvis.
• The common bile duct is made only of the hepatic
  and cystic ducts.
• The rectus abdominis is found on the posterior
  abdominal wall.
• The left kidney is lower than the right.

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Ricks Lab Work Results
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Ricks Upper GI CAT Scan
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Ricks Chest CAT Scan
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CHEST X-RAY
NORMAL CHEST X-RAY
RICKS CHEST X-RAY
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Some Definitions

• Secretion
• - discharge of materials synthesized by
  cells.
• Excretion
• - discharge of metabolic waste products
  from our cells. Occurs at skin, sweat glands,
  lungs, feces, and kidneys.

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Liver

• 5 functions
• Detoxification of blood
• Carbohydrate metabolism
• Lipid metabolism
• Protein synthesis
• Secretion of bile

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• Bile contains bile salts, water, pigments,
  cholesterol, and lecithin (a phospholipid)
• Bile salts act like detergents and EMULSIFY fats.
  Makes fat form into small droplets that are more
  soluble. Greater surface area makes it more
  digestible.

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• Bile is stored in the GALL BLADDER where it is
  concentrated. When fat is detected in the
  duodenum, the gall bladder contracts and bile is
  discharged into it.
• The COMMON BILE DUCT comes into the first inch of
  the duodenum. Its opening is called the AMPULLA
  OF VATER. This opening is controlled by the
  SPHINCTER OF ODDI. This sphincter relaxes when
  the gall bladder contracts.

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Pancreas

• Produces approx. 10 enzymes which are responsible
  for digestion.
• The PANCREATIC DUCT carries these enzymes
  directly into the common bile duct. Sometimes it
  empties directly into the duodenum (anatomic
  variance).
• Also secretes BICARBONATE which neutralizes the
  duodenal contents.
• The ISLETS OF LANGERHANS produce INSULIN and
  GLUCAGON.

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Spleen

• Stores blood
• Produces WBC
• Part of lymphatic system
• Found midaxillary, deep to ribs 9-11 and superior
  to the TPL.

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Abdominal Blood Vessels

• During your dissection, you should lift the
  spleen to notice the peritoneum going to it.
  This is the SPLENIC LIGAMENT. You will notice an
  artery in the dorsal direction this is the
  SPLENIC ARTERY. It is a branch off the CELIAC
  ARTERY.

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• The celiac artery is a branch off the aorta.
• The celiac artery also divides to give rise to
  the HEPATIC ARTERY (liver) and the LEFT GASTRIC
  ARTERY (stomach).
• The CRANIAL MESENTERIC ARTERY is another branch
  of the aorta which further divides into the
  CAUDAL PANCREATICODUODENAL, MIDDLE COLLIC,
  ILEOCOLIC, and branches to the intestines.

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• The CELIAC, CRANIAL MESENTERIC, and CAUDAL
  MESENTERIC serve blood supply to the entire
  gastrointestinal tract.
• The first branch of the celiac artery is the
  HEPATIC ARTERY. This serves the liver as well as
  giving rise to a few branches.

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• One branch of the hepatic artery serves the gall
  bladder. This is the CYSTIC ARTERY.
• Caudal to the cystic artery, is the
  GASTRODUODENAL ARTERY. This gives rise to the
  RIGHT GASTRIC ARTERY.
• The right gastric artery anastomoses with the
  LEFT GASTRIC ARTERY to give collateral
  circulation around the stomach.

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• Dorsal to the duodenum, the gastroduodenal artery
  branches. The CRANIAL PANCREATICODUODENAL ARTERY
  serves the pancreas and the duodenum. It is
  found between them. The other branch is the
  RIGHT GASTROEPIPLOIC .
• The last branch of the celiac artery is the
  SPLENIC ARTERY which gives rise to the LEFT
  GASTROEPIPLOIC ARTERY. The right and left
  gastroepiploic arteries form an anastomosis for
  collateral circulation.

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• The CAUDAL and CRANIAL MESENTERIC ARTERIES branch
  from the aorta.
• The cranial mesenteric artery branches are the
  CAUDAL PANCREATICODUODENAL ARTERY (anastomosis
  with the cranial), MIDDLE COLIC (middle colon) ,
  ILEOCOLIC (junction of ileum and colon), and
  INTESTINAL BRANCHES.

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• The caudal mesenteric artery branches
• 1. cranial rectal (hemorrhoidal artery)
• - rectum
• 2. left colic artery
• -anastomosis with the middle colic
  artery already mentioned.

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• The lateral branches of the aorta include the
• 1. Adrenolumbar artery
• -adrenal glands and muscles of the
  lower back.

Phrenic artery
Caudal phrenic
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• Renal artery
• - go to kidneys
• Gonadal artery
• - males testicular artery
• - females ovarian artery
• 4. Deep circumflex iliac artery

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• The terminal branches of the abdominal aorta are
  the EXTERNAL ILIAC ARTERIES which become the
  FEMORAL ARTERIES in the thigh.
• The aorta will become a short COMMON ILIAC ARTERY
  to end the INTERNAL ILIAC ARTERIES.
• The internal iliac goes inside the pelvis where
  the external iliac stays outside the pelvis.

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The Pelvis and Perineum

• Pelvic wall is formed by
• a. Pelvic girdle
• b. Sacrum
• c. Os coxae (ilium, ischium, and pubis)

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• The three os coxae bones (innominate bones) come
  together to form the ACETABULUM (hip socket).
• The PELVIC BRIM is a line that separates the
  FALSE PELVIS (superior to the brim) and the TRUE
  PELVIS (inferior to the brim).

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• The pelvic inlet is also formed by the PROMONTORY
  of the sacrum and a line drawn to the pubic
  symphysis.
• The PELVIC OUTLET is formed by a line from the
  inferior edge of the pubic symphysis to the tip
  of the coccyx and the plane extends laterally to
  the two ISCHIAL TUBEROSITIES.

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Sacral Promontory
Iliac Fossa
Pelvic Brim
Pubis
Pubic Symphysis
Acetabulum
Ischium
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• The pelvic inlet in females is wider than deep.
• The male pelvic inlet is heart shaped.
• The outlet of the female is round while on the
  male it is deeper than it is wide.
• In the female, the wide outlet leads to a wide
  PUBIC ARCH.

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Gender Differences in the Pelvis
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• There is no barrier that separates the abdominal
  and pelvic cavities. Therefore, intestines can
  drop into the pelvis and the bladder and uterus
  (females) can ascend into the abdomen.
• In males RECTOVESICULAR POUCH
• In females RECTOUTERINE POUCH

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• These pouches are sacs within the posterior
  portions of the pelvic cavities. Debris can
  accumulate in these cavities and be a source of
  infection.
• The peritoneal fluids circulate within these
  pouches.
• The bladder and uterus are outside the peritoneum
  (retroperitoneal)

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• The PELVIC DIAPHRAGM
• -muscular barrier across the pelvic outlet.
• -prevents pelvic contents from falling out.
• -LEVATOR ANI muscle (anterior)-raises the
  anus
• -COCCYGEUS muscle is posterior and smaller

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• The EXTERNAL SPHINCTER ANI is voluntary
• The INTERNAL SPHINCTER ANI is involuntary and
  part of the rectum.
• There is an opening in the levator ani
  (urogential diaphragm) for the UROGENITAL
  TRIANGLE and ARCH. This is where the urogenital
  organs pass.

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Reproduction

• A species goal is to reproduce.
• 2 types
• 1. ASEXUAL (without sex)
• a. 1 partner
• b. Parent and children are identical
• 2. SEXUAL
• a. 2 cells combine (fertilization)
• b. Children are similar but not
  identical to parents.

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• Sex cells (sperm and egg) are made by MEIOSIS.
  This form of cellular reproduction reduces the
  number of chromosomes by half.
• 23 chromosomes per egg
• 23 chromosomes per sperm
• 46 chromosomes per zygote (fertilized egg)

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• Humans are SEXUALLY DIMORPHIC. There are two
  distinct forms.
• The primary sex organs are the TESTES (male) and
  OVARIES (female). They produce sex cells called
  gametes. They are also MIXED GLANDS.
• In females, all meiosis is complete before
  birth-therefore, all the eggs that will be
  present are there at birth. They are dormant.
• In males, meiosis begins at puberty. Therefore,
  spermatozoa will be produced throughout the males
  life from puberty to death.

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• The gonads (testes and ovaries) produce hormones.
  They are endocrine glands.
• 1. Testosterone in males
• 2. Estrogen and Progesterone in females

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• Sexual Accessory Organs help get the gametes to
  where they have to go
• Males tubules, penis
• Females vagina, uterus, cervix, oviducts

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Secondary Sex Characteristics

• Due to hormones.
• Have nothing to do with reproduction.
• They include
• Facial and body hair
• Voice changes
• Mammary glands capable of milk production
• Increased musculature
• Shoulders, range of motion increase
• Increase in adipose tissue (fat) in female hip
  and buttocks
• Aggression increases
• Sex drive increases

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THE MALE

• Urine and semen both travel through the same tube
  (urethra)
• There is a cord from the inguinal ligament to the
  scrotum. This the SPERMATIC CORD which contains
  blood vessels, nerves, and vas deferens.

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• The URETERS from the kidneys lead to the caudal
  end of the bladder. The URETHRA passes caudally
  from the bladder.
• A short distance down the urethra you will find
  the PROSTATE GLAND. Inferior to this gland is
  the ROOT of the penis.

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• SPERMATIC FASCIA is the covering for the
  spermatic cord. The spermatic cord ends in a sac
  that contains the testes.
• The testes are oval shaped. Which contain the
  SEMINIFEROUS TUBULES.
• Remember, the testes begin in the abdominal
  cavity and descend into the scrotum.
• As they descend, the inguinal ligament evaginates
  and the spermatic fascia is formed form the
  aponeuroses of the inguinal ligament.

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• The peritoneum lining the fascial sac is the
  TUNICA VAGINALIS.
• Within the spermatic cord are muscle fibers from
  the internal oblique muscle. This forms the
  CREMASTER MUSCLE. When it contracts, this muscle
  lifts the testicle. This is important in
  maintaining an adequate temperature for sperm
  production.

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• The scrotum is the outer skin and muscle covering
  the testicles. The muscle within the scrotum is
  the DARTOS MUSCLE.
• This muscle is responsible for wrinkling the skin
  of the scrotum also helping in keeping a stable,
  cooler temperature.

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• The EPIDIDYMIS is attached to the testis. It has
  a head, body, and tail which empties into the vas
  deferens.
• The testicle is covered by a visceral layer
  called the TUNICA ALBUGINEA.

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• Internally, the testis has a network of
  SEMINIFEROUS TUBULES which combine to form a
  layer of ducts called the RETE TESTIS. The VAS
  EFFERENS are another layer that leads to the
  epididymis.
• Sperm is stored in the epididymis

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• Sperm finishes its development in the
  epididymis-gains a tail and its shape is
  streamlined.
• The head of the sperm contain enzymes that
  dissolve the COROLLA of the ovum.
• The vas deferens connects to the SEMINAL
  VESSICLES via the SEMINAL DUCT. After this the
  vas deferens is called the EJACULATORY DUCT.

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CAT
HUMAN
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• The urethra pass through the prostate gland and
  has many fenestrations. The prostate dumps
  materials into the semen through these holes.
  The ejaculatory duct empties into the PROSTATIC
  URETHRA.
• The prostatic urethra is connected to the
  BULBOURETHRAL GLANDS or COWPERS GLAND. Here
  lubricants are added to the semen. After this
  gland, the semen enters the PENILE URETHRA from
  which it leaves the body.
• The root of the penis is anchored to the body.
  The root has a bulb in the enter and two wings
  (crura) on either side.

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• The penis itself is made of three cylinders of
  spongy tissue.
• 1. 2 corpus cavernosum
• 2. 1 corpus spongisoum
• The spongiosum contains the penile urethra.
• The spongy tissue in all three cylinders contain
  spaces which become engorged with blood during
  sexual arousal erection.

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• These three cylinders compose the BODY of the
  penis.
• The body ends in the GLANS.
• Erection is an PARASYMPATHETIC response.
• Ejaculation is a SYMPATHETIC response.

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For Your Information..

• There are collagen fibers that run on the outside
  surface of the erectile tissue. This collagen
  lies at right angles to the circular fibers in
  the shaft. This design is to prevent the erect
  penis from buckling or kinking during intercourse.

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Identify the Following
Penis bladder Testicle
rectum Epididymis sacrum Vas
deferens prostate gland Ureter
bulbourethral gland Urethra
seminal vessicle Corpus spongiosum seminal
duct Corpus cavernosum crus of
penis Glans Scrotum Pubic symphysis
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THE FEMALE

• In the female cat, cut through the pubic
  symphysis. You will see a VESTIBULE. The
  urethra empties into the vagina through the
  UROGENITAL SINUS.
• In humans, the urethra empties into the vestibule
  with the vagina.
• At the end of the vagina, you will see the
  opening into the uterus. This is the CERVIX.

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• The UTERUS is a pear-shaped, muscular organ.
  This is where a fertilized egg implants for
  development. The inferior end of the uterus is
  called the INTERNAL OS, which communicates with
  the cervix. The EXTERNAL OS is the vaginal
  communication.
• Superior to the uterus are the openings for the
  OVIDUCTS. These tubes connect the uterus to the
  OVARIES.
• The end of the oviduct forms a funnel, or
  INFUNDIBULUM. There is a space between the ovary
  and infundibulum.

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• The cervix protrudes into the vaginal cavity.
  Here it is called the FORNIX. It has an
  anterior, posterior, and lateral section.
• The peritoneal cavity of the female is open as
  the vagina ultimately leads to the infundibulum.
  The peritoneal cavity of males is closed. There
  is no entrance into the abdomen from any male
  pelvic organ.

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HUMAN
CAT
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• The GREATER VESTIBULAR GLANDS (Bartholins
  Glands) are along the lateral margin of the bulb
  of the vestibule. They secrete a mucus substance
  for lubrication during sexual intercourse.

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GRAVID UTERINE HORN
WHAT IS THIS?
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Identify the Following
Pubic symphysis Sacrum Clitoris
Labia Linea
alba Uterus Rectum Anus Vagina Ovary Oviduct Infun
dibulum
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• After sperm is deposited into the vagina, they
  must swim toward the cervix. After entering the
  cervix, sperm must then find their way to one of
  the oviduct. Fertilization usually occurs in the
  distal 1/3 of the oviduct. The ZYGOTE (result of
  fertilization) then travels back to the uterus
  for implantation.

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• It takes 5 days for the zygote to reach the
  uterus. By the time it reaches its place of
  implantation, it is multicellular.
• At 6 weeks, you cannot distinguish between a male
  and female zygote.
• DIFFERENTIATION-cells change to form specific
  structures.

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cleavage
fertilization
morula
fundus
ovum
blastocyst
ovary
Ovarian ligament
body
fimbria
follicle
cervix
vagina
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• If the fetus is a male, the gonads will descend
  along the GUBERNACULUM, through the INGUINAL
  CANAL and the WOLFFIAN DUCT. The MULLERIAN DUCT
  in a male becomes associated with the kidney. If
  it is a female, the MULLERIAN DUCT becomes the
  female tube system. The gubernaculum becomes the
  round ligments of the ovary and uterus (female)

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The Perineum

• From the pelvic diaphragm to the skin is the
  perineum. It has the same superior boundary as
  the pelvic outlet.
• In reality, the perineum is the space between the
  rectum and genitals.
• It is divided into two triangles
• a. Posterior anal triangle
• b. Anterior urogential triangle

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• The perineum includes skin, fat, fascia,
  arteries, veins, lymphatics, and nerves.

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• There are small cilia attached to the
  infundibulum and within the oviduct.
• These cilia push the egg (ovum) along the length
  of the tube. The OVUM is the largest cell in the
  body.

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• The peritoneum that extends to the ovary is
  called the MESOVARIAN LIGAMENT.
• The mesentery to the uterus is the BROAD
  LIGAMENT.
• The ROUND LIGAMENT of the ovary and the ROUND
  LIGAMENT of the uterus both pass through the
  broad ligament.
• The two round ligaments are remnants of the
  GUBERNACULUM, an anchor for the ovary-uterus and
  uterus-inguinal ligament.

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So, what happens to the embryonic structures?
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• The following structures are HOMOLOGS (structures
  that have same origin but different functions in
  the two sexes)
• Testes ovaries
• Oviduct male urinary tract
• Vas deferens female urinary tract

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The Perineum

• Location from the pelvic diaphragm to the skin.
• In reality everything from the external
  genitals to the anus. This includes skin,
  arteries, fat, veins, capillaries, nerves, and
  lymphatics.
• It is divided into two triangles
• a. Anterior urogenital triangle
• b. Posterior anal triangle

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• If we were make a coronal section we would see
• The urogenital diaphragm
• - supports the urogenital structures
• Superior to the UGD is the DEEP PERINEUM.
  Inferior to the UGD is the SUPERFICIAL PERINEUM.

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• If we expose the inferior surface of the anterior
  urogenital triangle, we cannot see the levator
  ani because it is covered by the UGD.
• The bulb of the penis is anchored to the UGD by
  the BULBOSPONGIOSUS MUSCLE.

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• The crura (wings) of the penis are anchored to
  the ischium by the ISCHIOCAVERNOSUS MUSCLE.
• These muscles help to expel semen during
  ejaculation.
• In the female, the perineum is diamond shaped (as
  in the male)

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• The PERINEAL BODY extends and attaches to the
  anal opening.
• An EPISIOTOMY is an incision into the perineal
  body to prevent tearing during childbirth. An
  incision is much easier healed than a tear.
• In the female, the bulb and crura
  (bulbocavernosus and ischiocavernosus) come
  together to form the body of the CLITORIS.
• The penis and clitoris are homologs.

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A for TRUE B for FALSE

• The first branch of the aorta is the abdomen is
  the superior mesenteric.
• The acetabulum is made from the ilium, pubis, and
  sacrum.
• The levator ani is located posterior to the
  coccygeus.
• Gametes are haploid (have 23 chromosomes).
• Meiosis is the process that produces the sex
  cells.

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• The first gland that sperm pass through after
  leaving the testis is the seminal vesicles.
• The dartos muscle is responsible for lifting the
  testis in response to changes in temperature.
• Sperm is made in the epididymis.
• The seminiferous tubules are found in the
  prostate gland.
• Females have only estrogen and progesterone as
  their sex hormones.

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• 11. The true pelvis is located superior to the
  pelvic brim.
• The inguinal ligament is located between the ASIS
  and the public tubercle.
• The pelvic outlet is wider in the female than the
  male.
• The hepatic artery is a branch of the celiac
  artery.
• The urogenital diaphragm is the boundary between
  the pelvis and the abdomen.