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84 Tasks for the Veterinary Assistant

The liver’s main function is to filter toxins from the Posterior aorta
blood, metabolize drugs, and produce bile which is and vena cava
stored in the gallbladder. The bile is used in the diges- Adrenal gland
tion of fats. The pancreas produces digestive enzymes
which are excreted into the duodenum. It also secrets
insulin which breaks down sugars. Renal Kidney
Diseases that affect the gastrointestinal system often pelvis
cause vomiting and/or diarrhea. There are many rea-
sons for vomiting and diarrhea including stress, dietary Renal artery
indiscretion, bacterial toxins, or foreign bodies blocking Ureter and vein
part or all the digestive tract. Gastric dilation volvulus
(GDV), also known as bloat, is the dilation or expansion
and twisting of the stomach. The stomach fills with gas or Bladder
too much food which causes it to expand and then twist,
or flip over. This twisting blocks the passage of food cuts
off the blood supply causing necrosis and, if not caught Urethra
and treated early, death. Gastritis means an inflamma-
tion of the stomach and is usually brought on by eating FIGURE 5.18 Urinary system. Source: Wikimedia Commons. Used
inappropriate food. Ileus is the paralysis or cessation of under CC BY‐SA 3.0, https://commons.wikimedia.org/wiki/
normal intestinal movement. Irritable bowel disease File:Bladder_stone_ruler.jpg.
(IBD) is a condition where the intestines are overly
sensitive to food and/or stress. Pancreatitis is inflamma-
tion of pancreas brought on by ingesting rich or highly
salty food like ham. Parasites can cause diarrhea and
vomiting if the adult worm load is high. Parvovirus will
also cause extremely watery and bloody diarrhea.
Fecal samples are tested for parasites in order to
find the causative agent. Radiographs of the abdomen
may be ordered to check for a blockage. This will
often involve giving the animal a contrast medium to
make items visible. Endoscopy can also be utilized to
directly visualize the interior of the gastrointestinal
tract. Ultrasound can be used to indirectly visualize
structures in the abdominal cavity such as the liver and
gallbladder.

FIGURE 5.19 Urolith.
Urinary System
from toxic overload or poisoning. The bladder can also
The job of the urinary system is to filter the blood of become diseased. Incontinence is the failure to hold
waste products and maintain the balance of water in the urine. This can be caused by hormonal changes, often
blood. The main organs are two kidneys, one on each seen in older unspayed female dogs, structure, or muscle
side of the spinal column on the cranial end of the weakness. Feline lower urinary tract disease (FLUTD)
abdominal cavity (Figure 5.18). The kidney is made up symptoms include frequent trips to the litter box with or
of millions of nephrons which filter the blood as it flows without urine being expelled, straining to urinate, or
through the kidney producing urine. Urine flows out of bloody urine. It can be caused by several factors: block-
the kidney through a tube called a ureter which ends at age of the urethra with crystals, bacterial infections, ana-
the bladder. The bladder is a hollow organ that can tomic defects, tumors, or idiopathic cystitis. FLUTD can
expand to accommodate the urine. The bladder has a lead to blockage of the urethra and is considered a med-
sphincter that controls when it releases the urine to the ical emergency. The urine continues to be produced by
outside through the urethra. This is called urinating or the kidney and can eventually backup into the kidney
micturition. causing the animal to become toxic because the kidneys
Diseases that effect the kidney are seen more often as cannot work properly. Urinary tract infections (UTIs)
the animal ages. Chronic renal failure is when the kidney are usually caused by a bacterial infection and can hap-
can no longer filter properly or regulate the amount of pen to both cats and dogs. Uroliths or bladder stones
fluids in the blood. Acute renal failure is a sudden onset can form and cause bloody urine, straining to urinate,