Pig Lab

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Pig I; external anatomy, skeleton, digestion

Anatomy of a pig

Pig digestive system

Tongue
For taste
Pushing food into the esophagus

Papillae
Rough edges of that tongue that contain the taste buds

Hard and soft palate
Separate the nasopharynx from the mouth

Parotid gland
Secretes saliva (amylase enzyme) which breaks down starches into sugar

Stomach
Stores food
Begins digestion of tissues and proteins by secretion of gastric juices. These juices are very acidic (pH 1-2). The semi-digested stomach contents are called chyme

Esophagus
Transports food from the mouth to the stomach. Waves of involuntary muscle contraction (peristalsis) push food down the esophagus
Pylorus
A muscle that regulates the flow of chyme into the small intestine

Duodenum
The section of the small intestine immediately below the stomach. Digestive juices from the gallbladder, liver, pancreas and gland cells in the intestinal wall mix here with chyme to continue with digestion

Pancreas
As a digestive organ, the pancreas secretes hydrolytic enzymes and a buffer into the duodenum. The pancreas also acts as an endocrine gland

Liver
Regulating blood sugar levels
Converting lactic acid to glycogen
Lipid regulation
Deamination of amino acids
Detoxifying / storing toxins
Manufacturing plasma proteins
Manufacturing plasma lipid cholesterol
Storing vitamins and iron
Forming red blood cells in embryos
Destroying old red blood cells
Excreting bile pigments and salt

Small intestine
The primary site of hydrolysis of food and absorption of nutrients

Large intestine
Collects the waste from the small intestine and reabsorbs water

Caecum
Analogous to the human appendix
In herbivores it contains microorganisms capable of digesting cellulose

Colon
The end of the large intestine which ducts the waste out of the body

Anus
Where solid waste from the digestive system exits the body

Fetal pig video

External anatomy and directional terms

Dorsal

AnteriorPosterior

Ventral

Other important term
Proximal (closer to body) and distal (farther away)
Medial (toward midline of body) and lateral (towards the side)

External anatomy
Nares (nose)
Nictitating membrane (3rd eyelid)
Pinna (outer ear)
Tail
Umbilical cord
Skin
Periderm (flaky outer layer of skin)

Why dissect fetal pigs?
Pig anatomy and physiology is very similar to human anatomy and physiology •Organ transplants from pigs to humans may be possible

The endoskeletal system

Purpose
Attachment for muscles

Comparative structure
Bipeds vs quadrupeds
Aquatic vs terrestrial
Endo- vs exo- skeleton
Male or female?

Male Female

Digestive system structure and function

Structures:
Mandible – jaw bone
Tongue for ingestion; digestion (chewing, enzymes) begins •Papillae; bumps on tongue

Epiglottis; blocks glottis and trachea as food enters esophagus via the pharynx •Glottis; opening of trachea
Hard plate; front roof of mouth
Soft plate; behind hard plate. Blocks sinuses
Pharynx; space between mouth and esophagus
Tongue forms bolus as teeth chew. Bolus triggers sensory nerves in back of mouth to initiate swallowing

Masseter muscle; on jaw for chewing
Parotid gland; salivary gland
Submaxillary gland; salivary gland
Thymus glands; immune system
Thyroid gland; endocrine system
Trachea; respiratory system
Esophagus

Salivary glands secrete saliva loaded with amylase (initiates breakdown of starch). Peristalsis continues to carry food down esophagus toward stomach. Thyroid gland regulates metabolism. Thymus develops immune system

Thoracic cavity
- heart
-...
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