fetal pig anatomy

diaphragm

• thin muscular sheet that divides the thoracic and abdominal cavities

• aids in respiration or breathing

liver

• large brown lobed structure located at the anterior end of the abdominal cavity

• it metabolizes many drugs (including alcohol) and makes a substance similar to detergent for fat digestion called bile

gall bladder

• small sac-like structure located underneath the right part of the liver

• it collects bile, which is sent to the initial portion of the small intestine (duodenum) via the cystic and common bile ducts

stomach

• a pouch shaped organ that rests just underneath the liver in the upper left quadrant

• it is responsible for storing food and prepares it for digestion

spleen

• thin flat organ in the pig that lies along the left lateral margin of the stomach towards the extreme left side

• looks like a flat worm or leech

• this organ is involved with maturation and processing of immune cells that protect the body

duodenum

• the initial segment of the small intestine, which is located immediately after the stomach (straight part)

• this organ is the major location for food digestion

esophagus

• located at top of the stomach near diaphragm

• functions in swallowing

pancreas

• bumpy yellowish-brown gland located along bottom of the stomach and extending to the duodenum

• looks like “creamed corn”

• this organ makes digestive enzymes, which are carried by the pancreatic duct to the duodenum

• this organ also makes the hormone insulin, which promotes sugar uptake from blood

mesentery

• thin sheets of tissue that holds the internal organs in place and provide them with a blood supply and nervous input

illeum

• longest and most distal region of the three parts of the small intestine (curly part)

• further digestion occurs and nutrients are absorbed here

cecum

• a blind sac or “dead end” branch off of the large intestine

• it looks somewhat like a crooked finger

• it is found just below the juncture of the distal end of the ileum and the proximal end of the large intestine

appendix

• in humans this is located directly off the cecum

• pigs do not have this

large intestine or spiral colon

• this is a tightly wound coil of this organ

• this organ reabsorbs water from digested food

rectum

• this lies toward the lower back region of the pig and is firmly attached to the dorsal walls of the cavity

• indigestible materials are processed here by coliform bacteria and the remaining water is reabsorbed and the result is feces

• this organ opens to the outside via the anus

kidneys

• two bean shaped organs present on either side of the spine

• this organ are covered by the peritoneal membrane and are thus located retroperitoneal

• this organ also excretes harmful substances from the blood and form urine

adrenal glands

• these small glands are located at the anterior and medial surface of the kidneys

• these organs also have two separate parts that 1) regulate your metabolism and 2) produce the “adrenalin rush” you feel when frightened or angry

umbilical arteries

• in addition to the umbilical veins that connected the umbilical cord to the liver there are two arterial vessels that connect to the lower part of the abdominal cavity

• these vessels carry blood to the placenta where it picks up nutrients and oxygen

urinary bladder

• a large flattened sac that lies between the two umbilical arteries

• this organ stores urine

ureters

• two thin retroperitoneal tubes that connect the kidneys to the urinary bladder and enables urine flow

urethra

• the large tube that exits off the bottom of the urinary bladder

• the bladder must be pulled up and the urethra can be separated from the surrounding tissue

• this organ enables urine to flow from the urinary bladder to the urogenital opening

scrotal sac

• external pouch located at the posterior end of the male pig

• functions to keep sperm cooler during spermatogenesis

cremasteric pouch

• this is a thin walled elongated sac extending across the ventral surface of the thighs

• found within the scrotal sac and inguinal canals, it contains the testes and epididymis

testes

• open the distal end of the cremasteric pouch

• this is a small smooth structure inside

• produces sperm cells

epididymis

• coiled structure attached to each testis

• sperm cells produced in the testes pass through the epididymis and into the ductus deferens or vas deferens

penis

• located in the flap with the umbilical cord

• cut away the skin to reveal it

ovaries

• two small lentil shaped organs located near the midline in the most posterior region of the abdominopelvic cavity

uterine horns

• the pig uterus has two long horns that are designed to accommodate many neonates simultaneously, and its uterus is classified as “bicornate”

• the human uterus is designed for a single neonate and its relatively small or “simplex”

• because of the exaggerated length of the porcine uterus the fallopian tubes, which carry eggs from the ovaries to the uterus, are relatively small.

• the two stringy (ramen noodle like) structures that connect the ovaries to the central structure is this body part

uterus

• central structure where the pig’s uterine horns unite

vagina

• muscular tube that connects the uterus to the urogenital sinus

urogenital sinus

• the vagina and urethra open into a common tube that serves both reproductive and urinary functions in female pigs

• this is different from human females where the vagina and urethra exit the body via separate openings

thymus gland

• located on the anterior surface of the heart slightly to the left of midline

• this also extends forward into both sides of the neck

• all fetuses have this enormous gland but gradually shrinks throughout life

• like the spleen, this gland contains immune cells which function to protect the body

pericardium

• thin serous membrane beneath the thymus and covering the heart

heart

• this organ pumps blood to the body through the aorta, which is the muscular tube visible at the anterior end of the heart

• this also pumps blood to the lungs via the pulmonary arteries

lung

• lobed spongy structures located on either side of the heart

• functions in respiration by enabling gas exchange between the atmosphere and body

• amount of lobes on the left: 3

• amount of lobes on the right: 4

bronchial tubes

• y-shaped tubes that connect the two lungs to the trachea and to each other

trachea

• relatively easy to identify in the neck and thoracic cavity due to the presence of cartilage rings that give it a segmented appearance (looks worm or centipede like)

• these rings keep the thyroid from collapsing as it carries air

thyroid gland

• small brown-purple gland located in the neck region between the lobes of the thymus and superficial to the trachea

• this gland is important in regulating metabolism

larynx

• located at the anterior end of the trachea

• known as the “voice box”

esophagus

• this organ helps with swallowing

urogenital opening

• females: this opening is located near the anus

• males: the opening is located near the umbilical cord.

genital papilla

• female: this is present near the genital opening

• males: do not have this