internal anatomy

dorsal cavity

houses the nervous system

meninges

membrane that lines the dorsal cavity

parts of dorsal cavity

• cranial dorsal cavity

• spinal dorsal cavity (dorsal caudal)

cranial dorsal cavity

• in the head

• houses the brain

spinal dorsal cavity (dorsal caudal)

• houses the spinal cord

ventral cavity (front)

houses thoracic and abdominal cavities

thoracic cavity

• heart

• esophagus

• lungs

• trachea+bronchus

• thymus

thoracic cavity membrane

pleura

pericardium

membrane that lines the heart

mediastinum

• “space”

• houses organs, blood vessels, nerves, etc

what sits in between the thoracic and abdominal cavities

diaphragm

abdominal cavity

• GI tract

• stomach —> descending colon

• liver

• gallbladder

• pancreas

• spleen

abdominal cavity membrane

peritoneum

what is behind the abdominal cavity

retroperitoneal position

organs in the retroperitoneal position

• kidneys

• segmoid

• rectum

what is under the abdominal cavity

pelvic cavity

pelvic cavity organs

• bladder

• reproductive organs

which organ is in most species except horses and rats

gallbladder

gallbladder function

holds bile necessary for fat digestion

which organs vary with size in different species

• spleen

• thymus

• thyroid gland

• respiratory system

spleen function

• check and recycle old blood cells that dont work

• also works for immunity similar to lymph nodes

thymus function

• help develop t-cells

• shrinks with age

left thymus

cervical (neck) thymus

right thymus

heart thymus

thyroid gland function

produce hormone thyroxine, and has a lot of blood supply

isthmus

bridge between two thyroid lobes

• not all species have one of these

visceral layer

inner layer that surrounds the organ touching it directly

parietal layer

• outer wall-lining that touches muscle

• wraps around all organs in viscera

lesser omentum

double layer of peritoneum that connects stomach to liver

coronary ligament

double layer peritoneum that suspends the liver onto diaphragm, preventing liver from moving into pelvis

greater omentum

offers protection and stores a lot of fat (protects the GI tract like how ribcage protects heart/lungs)

mesentary

holds loops of GI tract and small/large intestine

intraperitoneal

organs are surrounded by peritoneum and suspended by mesentary

difference between retroperitoneal vs. intraperitoneal

retroperitoneal is covered partially in peritoneum, which intraperitoneal is covered completely

volvulus

• bloating

• caused by when mesentery system isnt where its supposed to be and the stomach flips onto itself

  • when this happens blood flow will stop and stomach will necros

pericardial effusion

• excess fluid accumulation within pericardium

  • will cause pressure and heart wont have normal rhythm and less circulation

• tx is to drain fluid manually (pericardiumcentesis)

serosal membranes

lines the body cavity but also enrobe each and every organ to prevent friction

• membrane is made up of continuous double layer of ceels called mesothelium which surround a thin layer liquid called serous fluid